Cyclin E and the retinoblastoma protein (Rb) are both important regulators of the G(1) phase in the cell cycle. Overexpression of cyclin E and lost expression of Rb has previously been observed in breast tumours at frequencies of 10-50% and 20-30%, respectively. We explored the prognostic role of cyclin E and Rb in breast cancer patients randomised for tamoxifen (TAM), CMF (cyclophosphamide, metotrexate, 5-fluorouracil) chemotherapy and radiotherapy (RT) and how their expression affects the patients response to treatment. Protein expression was assessed with immunohistochemistry. We found overexpression of cyclin E in 32.1% (71/221) of the tumours and loss of Rb expression in 25.0% (59/236). Increased expression of cyclin E correlated to dysfunctional p53 (P=0.003) while loss of Rb correlated to normal p53 status (P=0.001). Our results suggest that patients with high cyclin E tumours have less benefit from tamoxifen (ER+, TAM vs. no TAM; RR=0.97; 95% CI, 0.36-2.60) than patients whose tumours show low expression (ER+, TAM vs. no TAM; RR =0.41; 95% CI, 0.24-0.72). Cyclin E also tended to predict the benefit from radiotherapy with a local recurrence rate of 0.31 (RT vs. CMF; 95% CI, 0.12-0.93) for patients with low expression and 0.68 (RT vs. CMF; 95% CI, 0.2-2.32) for patients with high expression of cyclin E. When the p53 status was taken in consideration the results showed that patients with both normal p53 and normal Rb expression had considerably lower locoregional recurrence rate when treated with radiotherapy instead of CMF (RR=0.17; 95% CI, 0.052-0.58) as compared to patients with either altered Rb or p53 or both (RR=0.70; 95% CI, 0.28-1.73).
Several studies indicate that chemokines play important roles in colorectal mucosal immunity by recruiting leukocytes into and out of the lamina propria adjacent to the epithelium. The chemokine CXCL5 which is expressed by epithelial cells within colorectal mucosa is a chemoattractant for neutrophils and has been implicated in Crohns disease and ulcerative colitis. In addition, CXCL5 is one chemokine which promote angiogenesis related to cancer. The objective of this study was to determine by ELISA assay whether CXCL5 protein level is altered in colorectal cancer (CRC) tissues (n=80) compared with paired normal mucosa. Furthermore, the plasma CXCL5 levels from CRC patients (n=62) compared with controls (n=71) were also examined. Using a TaqMan system we screened for -156G -greater than C and +398G -greater than A CXCL5 gene variants in CRC patients (n=228) and a control group (n=231) to assess the role of CXCL5 genotype in CRC. The analyses showed that CXCL5 protein level in colorectal tumours was significantly (P less than 0.0001) higher than in normal tissue and was lower in plasma in CRC patients compared with controls (P=0.026). Immunohistochemistry revealed CXCL5 immunoreactivity mainly in epithelial cells of the colorectal carcinoma and in normal epithelial cells. Furthermore, patients who were -156C carriers had higher CXCL5 protein concentration compared with -156G carriers in normal tissue (P=0.027) and CXCL5 protein levels in cancerous tissue tended to be higher for the patient -156C carriers (P=0.059). To our knowledge this is the first report on the influence of CXCL5 gene variants and their relation to expression of CXCL5 protein in human CRC.
Accumulating evidence points out that chemokines play important roles in colorectal mucosal immunity by recruiting leukocytes into and out of the lamina propria adjacent to the epithelium. The chemokine, CCL28, which is expressed by epithelial cells within colorectal mucosa is thought to have dual roles as a chemoattractant for leukocytes expressing CCR10 and/or CCR3 and a mediator of antimicrobial activity. To date, there is little known about the presence of CCL28 in colorectal cancer. The objective of this study was to determine whether the CCL28 protein level is altered in colorectal tumours (n=76) compared with paired normal mucosa. Further, the plasma CCL28 levels from patients with colon and rectal cancer were also examined. Immunohistochemistry revealed heterogeneous CCL28 protein expression in tumour and normal epithelial cells. Analyses by ELISA showed that the CCL28 protein level in colon tumours was significantly (P less than 0.001) lower than in normal tissue and that the difference in CCL28 protein level between rectal tumour and normal tissue was not significant. Patients with a tumour localized in the colon had significantly (P less than 0.05) higher plasma CCL28 protein levels than patients with a tumour localized in the rectum. These discrepancies may suggest that there are different mechanisms and signalling pathways involved in the pathogenesis of cancer in the colon and rectum and thereby differentially promote the expression and secretion of CCL28 protein. Further studies on CCL28 protein in colorectal cancer with an extended number of patients are necessary to conclude whether tissue levels and plasma concentrations carry significant clinical relevance.
Human colon cancer cells were injected sub-cutaneously into 30 nude mice. After 8 days, the animals were divided into 3 equal groups. The first and second groups received an i.p. injection with 5-fluorouracil/leukovorin (5-FU/LV) for 5 days (20 mg and 10 mg/kg body weight respectively). On the first day of 5-FU/LV treatment, the first group received an i.p. injection of irinotecan (2.5 mg/kg body weight), and the second group received an i.p. injection with oxaliplatin (1 mg/kg body weight). The third group were injected i.p. with 100 microl saline solution containing octreotide, galanin and serotonin. Injections were given 3 times daily for 5 days with a total dose of 150 microg/kg body weight/day. Three days after the treatment, the animals were sacrificed. Whereas the animals treated with triple therapy held a stable body weight, animals treated with 5-FU/LV-irinotecan and 5-FU/LV-oxaliplatin had gradual weight loss, which amounted to approximately 25% of their body weight at the end of the experiment. Moreover, 2 mice in the group treated with 5-FU/LV-irinotecan died, most probably due to side effects. There was no statistically significant difference between the 3 groups regarding tumour proliferation, apoptosis, blood vessel density, EGF- and VEGF-expression. Treatment with triple therapy using octreotide, galanin and serotonin appear to be comparable to 5-FU/LV in combination with irinotecan and oxaliplatin. However, triple therapy seems to have a better safety profile.
Colorectal cancer is a disease that is associated with default in the balance of apoptotic regulation. In the present study apoptosis was examined in 158 colorectal adenocarcinomas using the terminal deoxynucleotidyl transferase mediated digoxigenin nick end labeling (TUNEL) method. The median apoptotic index (AI) was 0.95% (range 0-6. 68%). Eighty-two tumours exhibited AI 0.95%. We revealed a positive correlation between apoptosis and proliferation determined as the expression of proliferating cell nuclear antigen (PCNA, p=0.002). The frequency of apoptosis increased from Dukes' stage A, B, C to D (p=0.01). No correlations were found between apoptosis and the patients' sex, age, tumour location, growth pattern, differentiation, prognosis, bcl-2, p53 or K-ras. Our findings suggest that we should further investigate the relationship between apoptosis and cellular proliferative activity in colorectal cancer to evaluate whether this might provide additional information in the selection of patients for effective adjuvant therapy.
The human epidermal growth factor receptor (HER) 4 is a relative of HER2 and has been associated to endocrine breast cancer and prediction of tamoxifen response. In addition to PI3K/Akt and MAPK pathway activation, ligand binding to HER4 triggers proteolytic cleavage and release of an intracellular receptor domain (4ICD) with signaling properties. The aim of the present study was to analyze HER4 protein expression and intracellular localization in breast cancer tissue from patients randomized to treatment with or without adjuvant tamoxifen. To investigate HER4 expression and localization in response to estradiol (E2) and 4-hydroxytamoxifen (4-OHT) exposure, we also performed in vitro studies. Cytoplasmic, nuclear and membrane expression of HER4 protein was evaluated by immunohistochemical staining in tumor tissue from 912 breast cancer patients. Three different breast epithelia cancer cell lines were exposed to E2 and 4-OHT and mRNA expression was analyzed using qPCR. Further, nuclear and cytoplasmic proteins were separated and analyzed with western blotting. We found an association between nuclear HER4 protein expression and ER-positivity (P=0.004). Furthermore, significant association was found between cytoplasmic HER4 and ER-negativity (Pless than0.0005), PgR-negativity (Pless than0.0005), tumor size greater than20 mm (P=0.001) and HER2-negativity (P=0.008). However, no overall significance of HER4 on recurrence-free survival was found. After E2 exposure, HER4 mRNA and protein expression had decreased in two cell lines in vitro yet no changes in nuclear or cytoplasmic protein fractions were seen. In conclusion, nuclear HER4 seem to be co-located with ER, however, we did not find support for overall HER4 expression in independently predicting response of tamoxifen treatment. The possible influence of separate isoforms was not tested and future studies may further evaluate HER4 significance.
Most solid tumors display extracellular acidosis, which only partially overlaps with hypoxia and induces distinct adaptive changes leading to aggressive phenotype. Although acidosis is mainly attributable to excessive production of lactic acid, it also involves carbonic anhydrase (CA) IX-mediated conversion of CO(2) to an extracellular proton and a bicarbonate ion transported to cytoplasm. CA IX is pre-dominantly expressed in tumors with poor prognosis and its transcription and activity are induced by hypoxia. Here we investigated whether low extracellular pH in absence of hypoxia can influence CA IX expression in cell lines derived from glioblastoma, a tumor type particularly linked with acidosis. Our data show that extracellular acidosis increased the level of CA IX protein, mRNA and the activity of minimal CA9 promoter that contains binding sites for HIF-1 and SP-1 transcription factors. Mutation within each of these two biding sites reduced the promoter activity, but did not eliminate the increase by acidosis. Transfection of HIF-1alpha cDNA produced additive inducing effect with acidosis. Normoxic acidosis was accompanied by HIF-1alpha protein accumulation and transiently increased phosphorylation of ERK1/2. Expression of a dominant-negative mutant of ERK2 reduced the CA9 promoter activity in both standard and acidic conditions. Similar result was obtained by inhibitors of MAPK and PI3K pathways, whose combination completely suppressed CA IX expression and abolished induction by acidosis. Altogether, our results suggest that acidosis increases the CA IX expression via a hypoxia-independent mechanism that operates through modulation of the basic CA9 transcriptional machinery.
We examined biological and clinicopathological significance of individual and combined hMLH1, hMSH2, hMSH3 and hMSH6 expression with immunohistochemistry in 301 unselected colorectal cancers. Weak hMLH1 expression was correlated to microsatellite instability (P=0.04), negative p53 expression (P=0.005) and mucinous carcinomas (P=0.02). Weak hMSH2 expression was related to negative ras (P<0.001) and p53 expression (P=0.005), and better survival (P=0.03). hMSH2, hMSH3 and hMSH6, as well as hMLH1, hMSH2, hMSH3 and hMSH6, were combined into a 'functional' and a 'less-functional' group, respectively. Both 'less-functional' groups were/tended to be associated with microsatellite instability, negative ras and p53 expression, and better survival. In summary, hMLH1 and hMSH2 were more important when investigated individually, and the combined groups were more related to the mutator pathway, suggesting that combined deficiencies of the proteins are more efficiently involved in the mutator pathway. Our result from weak versus strong staining may suggest that the intensity of staining should be considered in future studies on mismatch repair proteins.
The MYCN gene is frequently amplified in unfavorable neuroblastoma tumors. Therefore, this study aimed at characterizing the novel junctions connecting the amplified DNA segments (amplicons) and obtaining tumor-specific PCR fragments for use in detecting minimal residual disease (MRD). High-density SNP arrays were used to map the end-points of the MYCN amplicons in a subset of neuroblastoma tumors. Primers were designed to give rise to a tumor-specific PCR product and were examined for MRD in the blood and bone marrow using quantitative PCR. Tumor-specific junction fragments were detected in all cases, confirming a head-to-tail tandem orientation of the amplicons and revealing microhomology at the amplicon junctions, thus suggesting a rolling circle caused by microhomology-mediated break-induced replication (MMBIR) as a possible mechanism initiating the MYCN amplification. We also evaluated the use of these junctions as tumor-specific targets for detecting MRD and observed that tumor DNA could be readily detected and quantified in either blood or bone marrow at a sensitivity of 1/10(6) tumor/control DNA. This study provides new information on the mechanisms of oncogene amplification and envisages means of rapidly obtaining highly sensitive PCR-based tools for tumor/patient-specific monitoring of treatment response and the early detection of relapse in patients with neuroblastoma.
The tyrosine kinase receptor EphB4 and its ligand ephrin-B2 interact through cell-to-cell contacts. Upon interaction, EphB4 transmits bidirectional signals. A forward signal inside EphB4-expressing cells is believed to suppress tumor growth, while inside the ephrin-expressing cells, an oncogenic reverse signal arises. In breast cancer cells with a high EphB4 receptor expression the forward signal is low, in part due to the low expression of the ligand ephrin-B2. Therefore, we hypothesized that by re-introducing the ligand in EphB4-positive cells, tumor suppression could be induced by the stimulation of the forward signal. This question was addressed in vitro by the stable lentiviral infection of breast cancer cells with either wild-type EFNB2 or with a mutant EFNB2-5F, unable to transmit reverse signaling. Furthermore, we investigated ephrin-B and EphB4 protein expression in 216 paraffin-embedded tumors using immunohistochemistry. The in vitro results indicated that ephrin-B2 expression was associated with a lower cell proliferation, migration and motility compared with the control cells. These effects were more pronounced when the cells lacked the ability to transmit the reverse signal (B2-5F). In clinical material, ephrin-B protein expression was associated with a positive estrogen receptor (ER) status, a low HER-2 expression and was negatively associated with Nottingham histologic grade (NHG) III. Ephrin-B expression indicated a good prognosis, whereas EphB4 expression was associated with a shorter metastasis-free survival in univariate and multivariate analysis. Furthermore, the prognostic value of EFNB2 and EPHB4 was confirmed at the gene expression level in public datasets. Thus, on the whole, the findings of this study suggest that ephrin-B2 expression is associated with less proliferation and lower motility of breast cancer cells and with a longer patient survival in breast cancer.
MAC30 is highly expressed in several types of tumors including colorectal cancers, however, its clinicopathological and biological significance in colorectal cancers is currently not known. The aim of our study was to investigate MAC30 expression in distant normal mucosa, adjacent normal mucosa, primary tumors and metastases of colorectal cancer, and to determine the relationship between MAC30 expression and clinicopathological and biological variables. MAC30 expression was immunohistochemically examined in distant normal mucosa (n = 54), adjacent normal mucosa (n = 123), primary tumors (n = 217) and lymph node metastases (n = 56) from colorectal cancer patients. MAC30 cytoplasmic expression was increased from distant normal mucosa to primary tumor and to metastasis (p < 0.0001-0.04). Furthermore, 40% primary and 37% metastatic tumors showed stronger cytoplasmic expression of MAC30 at the tumor invasive margins compared to inner tumor areas. Strong cytoplasmic expression of MAC30 in the metastasis was related to a poor prognosis (p = 0.04). MAC30 cytoplasmic expression was positively related to expression of proliferating cell nuclear antigen (p = 0.04), p53 (p = 0.04), nucleoporin 88 (p = 0.001), legumain (p = 0.004) and particularly interesting new cysteine-histidine rich protein (p = 0.004). However, MAC30 expression in the nucleus and stroma did not have any clinicopathological and biological significance (p > 0.05). In conclusion, MAC30 protein may play a role in development of colorectal cancer, and can be considered as a prognostic factor.
We quantitated the methylated fraction of CpG sites in the promoter regions of O-6-MGMT, p14(ARF), p16(INK4a), RASSF1A and APC1A in tumor tissue from patients with colorectal cancer (CRC) in order to determine if promoter hypermethylation of any of these genes predicts survival. DNA was isolated from 111 primary CRC and 46 matched normal colorectal mucosa samples from the same patients, obtained at primary surgery and DNA methylation was examined by Pyrosequencing (R). Follow-up time was up to 20 years. Patients showed partial promoter methylation in the following frequencies: O-6-MGMT, 34%; p14(ARF), 29%; p16(INK4a), 28%; RASSF1A, 14%; and APC1A, 27%. Normal mucosa was always unmethylated. CRC patients with methylated p14(ARF). gene promoter had significantly worse prognosis (p=0.036), whereas those with methylated O-6-MGMT had significantly better prognosis through the first 60 months post-treatment (RR 0.36; p=0.023). Methylation of one or more of the genes from the set p14(ARF), RASSF1A and APC1A, was significantly (p=0.021) associated with worse prognosis even adjusting for tumor stage and differentiation (RR 2.2, p=0.037). Thus, DNA methylation of the p14(ARF), RASSF1A and APC1A genes, diagnosed by Pyrosequencing, defines a poor prognosis subset of CRC patients independently of both tumor stage and differentiation. O-6-MGMT methylation may play a protective role.
P21WAF1/Cip1 (p21) translocates to the cytoplasm inducing cell cycle progression and survival upon Akt/PKB activation. We studied whether heregulin beta1 (HRGbeta1), that activates the PI3K/Akt and MAPK pathways, also misallocates p21. We also explored whether HRGbeta1 interferes with the effects of tamoxifen. The clinical material studied helped us to clarify whether p21 was associated with phosphorylated Akt, recurrence-free survival and response to tamoxifen. MCF-7 cells treated with HRGbeta1 -/+ E2 were analyzed by flow cytometry to observe how the different compounds affected tamoxifen-induced cell cycle arrest and apoptosis. Total cell lysate and nuclear and cytoplasmic fractions were used to detect p21, phospho-Akt and other proteins by Western blotting. Immunofluorescence was used to visualize p21+ cells upon HRGbeta1 and E2 stimulation. The localization of p21 in breast cancer was studied by immunohistochemistry in frozen tumor sections from 280 patients. In MCF-7 we found that HRGbeta1 counteracted the inhibition of p21 expression by tamoxifen and caused p21 cytoplasmic accumulation. HRGbeta1 partially counteracted the cytostatic effect of tamoxifen but abrogated its cytotoxic effect. The clinical material revealed that nuclear p21 (P=0.022) and cytoplasmic p21 (P=0.00001) were associated with phospho-Akt. Based on p21 cell location, we identified 3 subgroups of ER+ patients: the p21N+/C- group for whom tamoxifen was needed otherwise the survival was poor (P=0.0082), the p21N+/C+ or p21N-/C- group, that responded to tamoxifen (P=0.034), and the p21C+/N- group, that might not benefit from this treatment (P=0.7). In conclusion, HRGbeta1 inhibits tamoxifen-induced apoptosis, contributes to p21 cytoplasmic expression while the cellular localization of p21 interacts with the benefit from tamoxifen treatment.
A group of 133 primary oral squamous cell carcinomas were studied concerning a relationship between exposure factors and tumour biological parameters with a focus on the TP53 gene and p53 protein status. Tumours were evaluated using immunohistochemistry (IHC) for expression of p53, PCNA, Ki-67 and bcl-2 proteins. The TP53 gene was studied for mutations using PCR amplification of exons 5-9 and single strand conformation polymorphism (SSCP) analysis. The collected data were correlated to the exposure factors smoking, oral snuff, liquor, oral infections, dental factors, dental X-ray and iron deficiency. When compared with matched controls only oral infections, and reported HSV-infections in particular, gave statistically significant ORs (odds ratio) for all tumours (OR 8.0) as well as for the group of IHC p53 positive tumours (OR 12). No association between smoking and p53 positivity was found (OR 1.0).
In a retrospective analysis of a complete geographic series of cervical carcinomas treated by Wertheim-Meigs radical surgery, a number of important prognostic factors were evaluated and long-term survival data are presented. In all, 367 women with FIGO stage I-II tumors were included. The main histopathologic types were squamous cell carcinoma in 84% and adenocarcinoma in 12%. The mean age of the patients was 42.5 (range 19-68) years. In 125 women (34%), adjuvant radiotherapy was administered pre- or postoperatively. The median period of follow-up was 12 (range 2-27) years. In 88% of the specimens surgery (93% in stage I and 66% in stage II) was classified as radical with regard to the excision margins. This was an important and highly significant prognostic factor. If the margins were wide and free of tumor, the 10-year survival rate was 93%, but if margins were infiltrated by the tumor, the survival rate was 14%. Pelvic lymph node involvement was recorded in 52 cases (14%). The frequency of lymph node spread was associated with tumor stage (IA O%, IB 14%, IIA 32%). The probability of survival of the complete series was 93% at 5 years and 84% at 10 years. In cases of lymph node involvement, the 10-year survival rate was 57%. The preoperative tumor stage had a highly significant influence on long-term tumor-specific survival. Tumor grade was also a significant prognostic factor, but not the histologic type (squamous, adenosquamous, or adenocarcinoma). Age and parity were also insignificant prognostic factors. The tumor recurred in 59 cases (16%). The mean time to relapse was 28 months. The 10-year survival was 29% for this group of patients. Peroperative complications were recorded in 50 patients (14%). Excessive bleeding (11%) and urinary tract injuries (3%) were most frequent. Postoperatively, 101 patients (28%) had some kind of complication associated with the surgical procedure. Surgical complications were more frequent among women over 50 years of age. Bladder dysfunction (11%) and obstruction of the ureter (8%) were recorded most frequently. In 19 cases (5.2%), urinary tract or intestinal fistulas were diagnosed during the period of follow-up. With increasing experience of the surgeons and fewer stage II tumors, the frequency of fistulas associated with the surgical procedure decreased to 2.4% during the latter part (1975-90) of the period. Adjunctive postoperative radiotherapy increased the risk of late complications. In 8 cases (6.4%), serious complications associated with the combination of surgery and radiotherapy were reported.
The purpose of this study was to assess the response rate, toxicity, progression-free survival (PFS) and overall survival (OS) in a series of advanced stage ovarian carcinoma patients treated with a first-line weekly docetaxel and three weekly carboplatin regimens. All eligible patients were treated with intravenous docetaxel (30 mg/m(2)) on Days 1, 8 and 15, and carboplatin (area under the curve, 5) on Day 1; Q21 days for at least 6 cycles. Neurological tests, questionnaires, and the EORTC QLQ-C30 and OV28 were used for quality-of-life assessments. One hundred and six patients received at least one cycle of primary chemotherapy (median 6.0; range, 1-9) and they were evaluable for toxicity assessment. Eighty-five patients had evaluable disease and received at least 3 courses of chemotherapy and were evaluable for clinical response rate. The overall response rate was 78.8% (95% CI 70.1-87.5%) and the biochemical response was 92.8% (95% CI 87.2-98.4%). The median PFS was 12.0 months and the median OS was 35.3 months. Thirty-six patients (34.0%) experienced grades 3 and 4 neutropenia, which resulted in the removal of 3 patients. Six patients (5.7%) experienced grades 3 or 4 thrombocytopenia. No patients experienced grade 3-4 sensory neuropathy. Epiphora, nail changes and fatigue were frequently recorded non-hematological side effects. The tolerable hematological toxicity (no need for colony-stimulating factors) and the low rate of severe neurotoxicity (only grade 1-2) and response rates in line with the standard 3-week paclitaxel-carboplatin regimen for advanced primary ovarian carcinoma after suboptimal cytoreductive surgery make this regimen an interesting alternative in selected patients.
The prognostic significance of Bcl-2 expression in colorectal cancer has been intensively studied, however, the results were controversial in the whole group of colorectal cancer patients. We proposed that one of the main reasons for such controversial results may be that Bcl-2 played variable roles in the subgroup of patients. We, therefore, investigated the prognostic importance of Bcl-2 expression by using immunohistochemistry in the various subgroups of 147 patients with colorectal cancer. Among these tumours, 85 (58%) expressed Bcl-2 protein and 62 (42%) were negative. Bcl-2 expression was positively related to DCC expression (p=0.0002). Survival analyses in the subgroups of the patients showed that lack of Bcl-2 expression was related to a worse prognosis in the male patients (p=0.02) but not in female patients (p=0.53), in the patients with DNA diploid tumours (p=0.005) not in the patients with non-diploid tumours (p=0.46), and in the patients with ras negative tumours (p=0.01) not in the patients with ras positive tumours (p=0.25). Bcl-2 expression was not related to prognosis in the total group of the patients (p=0.20). In conclusion, Bcl-2 protein may play variable prognostic roles in the subgroups of the patients with colorectal cancer. Analysis of Bcl-2 expression in the tumour may be of value in predicting prognosis and therapeutic response.
Radiotherapy is widely used in the treatment of breast cancer and reduces the risk of loco-regional recurrence. Overexpression of the erbB2 receptor occurs in 20-30% of all breast cancers, and seems to be involved in chemotherapeutic resistance of breast cancer cells and radioresistance of lung cancer cells. The hypothesis of this study was that erbB2 confers resistance to radiation-induced apoptosis in breast cancer cells through the phosphatidylinositol 3-kinase (PI3-K)/Akt signalling pathway. Two human breast cancer cell lines were used, BT-474 and MCF-7. BT-474 cells overexpress erbB2 and have mutated p53, while MCF-7 have normal expression of erbB2 and functional p53. The cells were treated with the PI3-K inhibitor wortmannin or the erbB receptor ligand heregulin-ß1, which is expressed by both malignant and stromal cells in vivo. After pharmacological treatment, the cells were irradiated with 10 Gy gamma-radiation. Consistent with the p53 status in the cell lines, gamma-radiation caused G1 arrest in MCF-7 cells, but not in BT-474 cells. 10 Gy gamma-radiation increased apoptosis by on an average 76% (95% CI, 44-109%) in MCF-7. Treatment of MCF-7 with heregulin-ß1 decreased apoptosis by 66% (95% CI, 48-84%) compared to the untreated controls. In BT-474 cells, wortmannin in combination with radiation resulted in 119% (95% CI, 76-161%) more apoptosis compared to wortmannin alone, whereas radiation alone resulted in 45% (95% CI, 15-75%) increased apoptosis. This radiosensitising effect was not seen in MCF-7. Furthermore, transfection of MCF-7 cells with constitutively active Akt made the cells more resistant against apoptosis. Taken together, our results support the hypothesis that the erbB2/PI3-K/Akt signalling pathway is involved in resistance to radiation-induced apoptosis in breast cancer cells in which this signalling pathway is overstimulated.
Human colon cancer cells were injected subcutaneous in nude mice. After 8 days the animals were divided in two groups, the first group received triple therapy with octreotide, galanin and serotonin (40 microg/kg body weight/day) through an ALZET osmotic pump implanted intraperitoneally (i.p.) for 14 days, followed by 5 days of subcutaneous injections (200 microg/kg body weight/ day). The second group was injected i.p. for 5 days with 5-fluorouracil/leukovorin (5-FU/LV) at concentrations of 4 mg and 2 mg/kg body weight, respectively. After 9 days without any treatment, the mice received i.p. injection with 5-FU/LV (20 mg and 10 mg/kg body weight/day, respectively) for another 5 days. The volume and weight of the tumours were measured at the end of the experiment. Apoptosis, proliferation, blood vessels, epidermal growth factor (EGF) and vascular endothelial cell growth factor (VEGF) were detected with immunocytochemistry. Apoptosis was also detected using the TUNEL-method. Quantification was performed using computed image analysis. There was no statistical significance between tumours treated with 5-FU/LV or triple therapy regarding the volume and weights of the tumours, apoptotic, proliferation, VEGF indces and the density of tumour blood vessels. The EGF labelling index was, however significantly lower in the tumours treated with triple therapy than those treated with 5-FU/LV. In conclusion, treatment with triple therapy using octreotide, galanin and serotonin appear to be comparable with 5-FU/LV that is the standard chemotherapeutic agent for colorectal cancer.
Fibroblast activation protein-alpha (FAP-alpha) promotes tumor growth and cell invasiveness through extracellular matrix degradation. How ultraviolet radiation (UVR), the major risk factor for malignant melanoma, influences the expression of FAP-alpha is unknown. We examined the effect of UVR on FAP-alpha expression in melanocytes, keratinocytes and fibroblasts from the skin and in melanoma cells. UVR induces upregulation of FAP-alpha in fibroblasts, melanocytes and primary melanoma cells (PM) whereas keratinocytes and metastatic melanoma cells remained FAP-alpha negative. UVA and UVB stimulated FAP-alpha-driven migration and invasion in fibroblasts, melanocytes and PM. In co-culture systems UVR of melanocytes, PM and cells from regional metastases upregulated FAP-alpha in fibroblasts but only supernatants from non-irradiated PM were able to induce FAP-alpha in fibroblasts. Further, UV-radiated melanocytes and PM significantly increased FAP-alpha expression in fibroblasts through secretory crosstalk via Wnt5a, PDGF-BB and TGF-beta 1. Moreover, UV radiated melanocytes and PM increased collagen I invasion and migration of fibroblasts. The FAP-alpha/DPPIV inhibitor Gly-ProP(OPh)(2) significantly decreased this response implicating FAP-alpha/DPPIV as an important protein complex in cell migration and invasion. These experiments suggest a functional association between UVR and FAP-alpha expression in fibroblasts, melanocytes and melanoma cells implicating that UVR of malignant melanoma converts fibroblasts into FAP-alpha expressing and ECM degrading fibroblasts thus facilitating invasion and migration. The secretory crosstalk between melanoma and tumor surrounding fibroblasts is mediated via PDGF-BB, TGF-beta 1 and Wnt5a and these factors should be evaluated as targets to reduce FAP-alpha activity and prevent early melanoma dissemination.
Whether bcl-xL and bcl-2 play an essential role in melanoma progression and UVB-induced apoptosis is not completely understood. We investigated the expression of bcl-xL and bcl-2 in matched primary and metastatic melanoma tumors and melanoma cell lines from the same melanoma patients to clarify the importance of bcl-xL and bcl-2 in melanoma progression and in UVB-induced apoptosis. The expression of bcl-xL and bcl-2 proteins was examined by immunohisto(cyto)chemistry and Western blot in melanoma tumors and melanoma cells. Cellular viability and apoptosis were estimated after the melanoma cells were exposed to 30, 60 and 180 mJ/cm2 UVB. Both primary melanoma tumors and melanoma cells showed lower expression of bcl-xL and bcl-2 proteins estimated as frequency of positive cells than their matched metastatic tumors and cells in vitro. After exposure to UVB, the cell viability decreased and the number of apoptotic cells increased in both primary and metastatic melanoma cell lines. These changes were more pronounced in the primary melanoma cells than in the matched metastatic cells. After UVB exposure, the expression of bcl-xL protein decreased in primary melanoma cells in a dose- and time-dependent manner, but the expression of bcl-2 was not influenced. The expression of bcl-xL and bcl-2 proteins was increased during melanoma progression from primary to metastatic melanoma. Reduction of bcl-xL, but not bcl-2 expression was involved in UVB-induced apoptosis in primary melanoma cells.
p16INK4a gene mapped at chromosome 9p21 region encodes a tumor suppressor protein p16 which is frequently inactivated in human cancers, including skin melanoma. In order to clarify the importance of p16 alterations in melanoma, we examined the deletions of p16INK4a and expression of p16 protein in eight unselected primary and metastatic melanoma cell lines from human skin melanomas. Normal skin melanocytes were used as controls. Deletions of entire exons in the p16INK4a gene were detected by PCR technique and expression of the p16 protein was examined by Western blotting and immunocytochemistry. Results showed that the fragments from exons 2A, 2C and 3 in p16INK4a gene were totally deleted in the metastatic melanoma cell line, FM28.7 and the fragment from exon 3 was deleted in the metastatic melanoma cell line, FM55M2. P16 protein was strongly expressed in two of the primary melanomas cell lines (FM55P and RaH3). The p16 protein was weakly expressed in one of the metastatic melanoma cell lines (FM55M1) and negative in the other metastasis (FM55M2) as compared to their matched primary melanoma cells (FM55P). The p16 protein was strongly expressed in normal skin melanocytes. Immunocytochemistry showed that p16 protein was mainly localized in the nuclei of the melanoma cells and normal melanocytes, if it was expressed. Deletions of p16INK4a gene was uncommon and loss of p16 protein expression was common event in melanoma, especially in the later stages of melanoma.
Several genetic alterations have been implicated in the development of malignant melanoma, but the expression of oncogenes, tumour suppressor, mismatch repair and apoptosis-related genes and their interactions in melanoma have not been completely clarified. We simultaneously examined the expression of p73, c-erbB-2, ras, p53, Mdm2, p27, DCC, hMLH-1, hMSH-2, bcl-2, Bax and NF-kappaB, by immunocytochemistry, in both primary and metastatic melanoma cell lines derived from melanoma patients. p73 was expressed in 7/8 cell lines, but stronger expressed in the metastatic cells than in the primary melanoma cells. c-erbB-2 was detected in all 8 cell lines and ras in 2/5 metastases. p53 was found in all the cell lines and Mdm2 in 1/8 of the cell lines. In the same patient, the intensity of p27 expression was decreased from the primary to the metastatic tumours. bcl-2 was expressed in all the cell lines. Bax was absent in 5/8 cell lines. In the same patient, Bax was weakly expressed in the primary tumour but lacking in the metastases. The data demonstrate that overexpression of p73, c-erbB-2, p53 and bcl-2, and loss of Mdm2 and Bax may interact and play important roles in the development and aggressiveness of human melanoma.
We investigated whether p27 and mitogen-activated protein kinase (MAPK) proteins were involved in all-trans retinoic acid (atRA)-induced apoptosis and cell cycle arrest. Matched primary and metastatic melanoma cells were exposed to atRA. Apoptosis and cell cycle were detected by flow cytometry. Expression of p27, Ras, B-raf, Mek and Erk proteins was examined. Results showed that atRA induced apoptosis and cell cycle arrest in both primary and metastatic melanoma cells. The primary melanoma cells were more vulnerable than their matched metastatic cells. Expression of p27 was increased, while MAPK proteins were decreased, this response was dose- and time-dependent. Alterations of these proteins were more pronounced in primary melanoma cells than in the matched metastases. These data indicate that up-regulation of p27 and down-regulation of MAPK proteins were involved in atRA-induced apoptosis and cell cycle arrest in melanoma.
We have previously shown that all-trans-retinoic acid (atRA) induces apoptosis in melanoma cells and primary melanoma cells are more sensitive to the exposure of atRA than the matched metastases. However, mechanisms behind the atRA-induced apoptosis have not been studied. In this study, we used a similar cell culture model system of matched primary and metastatic melanoma cells from the same patient to investigate whether p53 and bcl-2 family proteins were involved in atRA-induced apoptosis. The primary and metastatic melanoma cells were exposed to 0.1 and 10 micro M atRA in serum-free RPMI 1640 cell culture medium in the dark for up to 96 h. The protein expression of p53, p21, bax and bcl-2 were examined by Western blotting and immunocytochemistry. Expression of p53, p21 and bax was increased, and bcl-2 was decreased in melanoma cells after exposure to atRA at different concentrations for various periods of time. The changes of p53, p21, bax, and bcl-2 protein levels were dose- and time-dependent. The primary melanoma cells were more sensitive to the atRA treatments than cells from matched metastatic melanoma. These data indicate that p53, p21, bax and bcl-2 proteins were involved in atRA-induced apoptosis in melanoma cells. Modification of these protein levels in the tumour cells might be beneficial for early treatment of melanoma.
Cutaneous melanoma is a tumor with high metastatic potential, but the mechanisms leading to progression are still not fully understood. In this study, we examined whether p16, p27, p53, p73 and Nup88 proteins were involved in the progression from primary to metastatic melanomas by immunocytochemistry and Western blotting in eleven melanoma cell lines from five matched primary and metastatic melanomas. We demonstrated that the primary and metastatic melanomas expressed differently p16, p27, p73 and Nup88 proteins. When expressed in the primary melanoma cells p16 and p27 were lost or reduced in almost all the metastatic melanoma cell lines. In contrast, p73 and Nup88 were expressed in most of the tested melanoma cell lines and were increased in the metastatic melanomas. p53 was expressed at the same level in both the primary and metastatic melanoma cells. These data suggest that a reduced expression of p16 and p27 and an enhanced expression of p73 and Nup88 might play an important role in the progression of melanoma from primary tumor to metastasis.
p27 is a cyclin-dependent kinase inhibitor which regulates progression of cells from G1 into S phase in a cell cycle. Loss of the negative regulator may contribute to oncogenesis and tumor progression. The aim of this study was to examine p27 expression in normal mucosa, primary and metastatic tumors from patients with colorectal adenocarcinomas and to analyze association of p27 with patient survival and clinicopathological variables. p27 expression was estimated by immunohistochemistry in 178 primary colorectal cancers, 34 lymph node metastases and 48 normal mucosa samples from patients with colorectal adenocarcinoma. Associations of p27 with patient survival, clinicopathological characteristics and expression of p53, p73 and DCC were analyzed. Loss of p27 was found in 51% of primary tumors, 68% of metastases and 56% of normal samples. The intensity of p27 staining was similar in the matched primary tumor, metastasis and normal mucosa. In patients with Dukes' B or with proximal tumors, the loss of p27 predicted poorer prognosis (p = 0.03 and p = 0.05, respectively). However, there were no significant differences in the patients with other individual Dukes' stage or distal tumors. No relationships were found between p27 and patients' gender, age, tumor location, growth pattern and expression of p53, p73 and DCC (p > 0.05). The data suggest that loss of p27 was associated with poor prognosis in patients with Dukes' B tumor or those with proximal tumor. p27 might be a useful marker to identify the more progressive tumors in these groups.