Enhancement of effects of irradiation by gemcitabine in a glioblastoma cell line and cell line spheroids

Background and purpose To determine the cytotoxicity of, and radioenhancement by, gemcitabine on a glioma cell line grown as a monolayer and as spheroid cultures.Material and methods We used a human glioma cell line, Gli-6, which originated from a biopsy specimen of a patient with a glioblastoma multiforme. Spheroids of Gli-6 were prepared by seeding a single cell suspension on agarose-coated Petri dishes. Clonogenic and growth delay assays were used to determine radio-chemosensitivity of monolayer cultures. The growth delay assay was used to determine that of Gli-6 spheroid cultures.Results Spheroid cultures were found to be more resistant to irradiation with/or without gemcitabine than monolayer cultures. Whereas gemcitabine significantly enhances the radiation effect of exponentially growing Gli-6 monolayer cultures at minimal cytotoxic concentrations (10 nM, 24 h), no enhancement was seen in confluent monolayer cultures and in large spheroids at the same concentration. In small spheroids no enhancement was observed at a low-dose gemcitabine (10 nM for 24 h), but an enhancement was observed at higher concentrations (100 nM for 24 h).Conclusion Gemcitabine can lead to enhancement of the effects of X-irradiation in both monolayer as spheroid glioblastoma cultures. The lack of enhancement in confluent monolayer cultures supports the view that cell cycle distribution of cells is important in radiosensitisation by gemcitabine     

Gefitinib enhances the effects of combined radiotherapy and 5-fluorouracil in a colorectal cancer cell line

Purpose

In a phase I/II trial, patients with locally advanced rectal cancer received preoperative radiotherapy (RT) and concurrent with 5-fluorouracil (5-FU) and gefitinib. Results were promising. To elucidate the molecular and biological effects, we replicated the schedule in the LoVo human colorectal adenocarcinoma cell line.

Methods

RT (2 Gy daily for 3 days), 5-FU (0.3, 0.6, 1.25, 2.5, 5, 10 μM) and gefitinib (0.2, 0.4, 0.8 μM) were administered alone, in double combinations and all together. We assessed viable cells, cell cycle, cyclin, p53 and p21 expression, signalling pathways by means of phosphorylated epidermal growth factor receptor (p-EGFR), p-AKT and p-ERK 1-2 and clonogenic capacity.

Results

RT and 5-FU were cytotoxic. Gefitinib was cytostatic. RT reduced clonogenic capacity more than 5-FU. 5-FU induced more cell death than RT, but surviving cells were proliferative (cyclins and p-EGFR increased). 5-FU?+?RT had a synergistic effect. Gefitinib, enhancing G1 accumulation, reduced proliferation of cells surviving 5-FU and 5-FU?+?RT. It slightly increased the cytotoxicity of RT and 5-FU.

Conclusions

As gefitinib limited the proliferation rate of cells surviving 5-FU and 5-FU?+?RT in the LoVo cell line, it may be a useful addition to chemotherapy and RT in rectal cancer patients.     

Relationship between VEGF and p53 expression and tumor cell proliferation in human gastrointestinal carcinomas

Purpose The vascular endothelial growth factor (VEGF) and p53 play important roles in the growth of tumor. However, the relationship between the expression of VEGF and p53 and tumor cell proliferation in human gastrointestinal cancer remains unknown. In the present study, therefore, we have examined the relationship between VEGF and p53 expression and tumor cell proliferation in gastrointestinal carcinoma (GITC), as well as the association between these biomarkers and clinicopathological factors. Methods Surgical specimens from 30 patients with GITC were examined for VEGF, p53, and proliferating cell nuclear antigen (PCNA) expression by immunohistochemical staining. Results We found a predominant VEGF expression of moderate intensity in 16(54.84%) of 30 GITC cases, while p53 expression was mainly high in 13(45.16%) of 30 GITC cases. PCNA expression was high in 20(64.52%) of 30 GITC cases. Tumor size, infiltration, vascular invasion, and gastritis were significantly correlated with VEGF, p53, and PCNA expression. There was a significant correlation between VEGF and p53 expression (P = 0.0001), VEGF and PCNA expression (P = 0.00004), and between p53 expression and PCNA expression (P = 0.0016). When the VEGF and p53 expression, and PCNA expression were considered together, both VEGF and p53 expression were not significantly associated with PCNA. A significant correlation between the PCNA expression and the mitotic index (P = 0.0016) was also found. Conclusion These results demonstrate that VEGF and p53 expression are significantly correlated as independent prognostic factors with tumor cell proliferation, and might be associated with relevant events involved in gastrointestinal tumor biology.     

曲古抑菌素A对甲状腺鳞癌SW579细胞株p53和p21表达的影响

目的观察曲古抑菌素A(TSA)对甲状腺鳞癌SW579细胞株生长增殖及p53和p21表达的影响,进而探讨TSA抗甲状腺癌的作用机制。方法体外培养SW579细胞,实验分为DMSO组、TSA组(终浓度为50、100、200、400 nmol/L),采用MTT比色法测定细胞增殖活性;用RT-PCR方法检测SW579细胞p53及p21的mRNA表达;用Western blot方法检测SW579细胞p53及p21的蛋白表达。结果 MTT结果显示,TSA可明显抑制SW579的增殖,并呈剂量依赖性。RT-PCR与Western blot检测结果表明,与未加TSA组比较,TSA组随着浓度的逐渐加大,p21 mRNA和蛋白表达水平明显升高;p53 mRNA表达不变,而p53蛋白表达水平上调。结论 TSA在一定浓度范围内对甲状腺鳞癌细胞株SW579有剂量依赖性地增殖抑制作用,其机制可能与TSA提高SW579细胞p53的表达,进而再上调p21的表达有关。     

Proliferation of tumor spheroids after shock-wave treatment

Multicellular tumor spheroids (MCTS) grown from the bladder cancer cell line RT112 and from the prostate cancer cell line PCA were exposed to 200 or 800 electromagnetically generated focused ultrasound shock waves. RT112 cells showed a distinct but transient decrease in proliferation whereas the effect of PCA cells was less pronounced. Flow-cytometric measurements of DNA content and Ki67 expression revealed no significant changes in the cell cycle distribution. The capacity of RT112 cells exposed to 800 shock waves to re-grow as MCTS was markedly decreased, indicating an alteration of intercellular adhesion.Abbreviation MCTS multicellular tumor spheroids     

The intrinsic radioresistance of glioblastoma-derived cell lines is associated with a failure of p53 to induce p21BAX expression

Radiation is the primary modality of therapy for all commonly occurring malignant brain tumors, including medulloblastoma and glioblastoma. These two brain tumors, however, have a distinctly different response to radiation therapy. Medulloblastoma is very sensitive to radiation therapy, whereas glioblastoma is highly resistant, and the long-term survival of medulloblastoma patients exceeds 50%, while there are few long-term survivors among glioblastoma patients. p53-mediated apoptosis is thought to be an important mechanism mediating the cytotoxic response of tumors to radiotherapy. In this study, we compared the response to radiation of five cell lines that have wild-type p53: three derived from glioblastoma and two derived from medulloblastoma. We found that the medulloblastoma-derived cell lines underwent extensive radiation-induced apoptotic cell death, while those from glioblastomas did not exhibit significant radiation-induced apoptosis. p53-mediated induction of p21^BAX is thought to be a key component of the pathway mediating apoptosis after the exposure of cells to cytotoxins, and the expression of mRNA encoding p21^BAX was correlated with these cell lines undergoing radiation-induced apoptosis. The failure of p53 to induce p21^BAX expression in glioblastoma-derived cell lines is likely to be of biologic significance, since inhibition of p21^BAX induction in medulloblastoma resulted in a loss of radiation-induced apoptosis, while forced expression of p21^BAX in glioblastoma was sufficient to induce apoptosis. The failure of p53 to induce p21^BAX in glioblastoma-derived cell lines suggests a distinct mechanism of radioresistance and may represent a critical factor in determining therapeutic responsiveness to radiation in glioblastomas.     

抑制干扰素诱导蛋白p204表达促进大鼠血管外膜成纤维细胞生长与迁移

目的观察干扰素诱导蛋白p204表达抑制后对大鼠血管外膜成纤维细胞(VAF)凋亡、增殖与迁移的影响及其部分机制。方法应用Ifi204小干扰RNA(si RNA)转染VAF使Ifi204基因沉默(Ifi204-si RNA组),以非特异性si RNA转染作为其转染阴性对照组(Con-si RNA组)和未经处理的VAF作为未干预阴性对照组(Neg组)。用MTT法检测VAF细胞增殖,流式细胞仪检测细胞凋亡,细胞划痕法和Transwell法测定细胞迁移情况,应用实时荧光q RT-PCR和Western blot分别检测p204、p53及p21的m RNA和蛋白表达。结果与Con-si RNA组和(或)Neg组相比,Ifi204-si RNA组的p204、p53及p21的m RNA和蛋白表达减少(P0.05),细胞凋亡率下降(P0.05),细胞增殖及迁移速度提高(P0.05)。结论抑制p204表达可减少大鼠VAF细胞凋亡,促进其增殖与迁移,其机制可能部分与抑制p53及p21表达有关。     

槲芪癥消汤对人肝癌细胞株HepG2.2.15增殖和凋亡的影响

目的:研究槲芪癥消汤对体外培养的人肝癌细胞株HepG2.2.15的增殖、凋亡、迁移能力、细胞内p53基因及蛋白表达量的影响,揭示该方可能的抗肿瘤机制。方法:应用不同浓度的槲芪癥消汤处理细胞,MTT法测定细胞增殖抑制率,Transwell检测细胞侵袭能力、流式细胞术检测细胞凋亡情况、rt-qPCR及Western blot检测细胞内p53的RNA及蛋白的表达变化。结果:槲芪癥消汤对HepG2.2.15细胞增殖有明显的抑制作用,使细胞的侵袭能力明显下降,并可促进细胞凋亡,同时细胞内p53的RNA及蛋白表达量明显增加,与对照组比较,差异均有统计学意义(均P<0.05)。结论:槲芪癥消汤能抑制肝癌HepG2.2.15细胞的增殖、侵袭,促进其凋亡,可能与促进细胞内的p53基因表达有关。     

Suppression of the proliferation and migration of oncogenicras-dependent cell lines,cultured in a three-dimensional collagen matrix,by flavonoid-structured molecules

The effects of 7-hydroxycoumarin, genistein and quercetin on tworas-oncogene-driven tumour cells (rat breast adenocarcinoma and human bladder carcinoma) were investigated using cellular (proliferation and migration) and molecular targets (p21 ^ras GTPase activity and intracellular amount of p21 ^ras protein). All three compounds inhibited the growth of both cell lines. Genistein was the most effective substance. Further-more, 7-hydroxycoumarin and genistein affected the motile machinery of both cell lines because major fractions of the cells were slowed down or stopped locomotion. The phorbol ester, phorbol 12-myristate 13-acetate (PMA), a well-known tumour promoter, increased the locomotion behaviour of the cells; the time of migration, the velocity and the distance of migration increased under the control of PMA. 7-Hydroxycoumarin decreased the relative amount of intracellular p21 ^ras , and concomitantly a PMA-induced decrease of p21 ^ras , GTPase activity could be partially antagonized by 7-hydroxycoumarin. Because of the low toxicity and the mode of action evaluated, it is likely that the best role for these substances may be adjuvant therapy of some malignancies following surgery. Profiles directed to migration and proliferation inhibition make these drugs exceptional candidates for chemopreventive strategies in tumours diagnosed as having increasedras oncogene levels.Abbreviations PMA phorbol 12-myristate 13-acetate - PMS phenazine methosulphate - RBA rat breast adenocarcinoma - XTT 2,3-bis(2-methoxy-4-nitro-5-sulphophenyl)-2H-tetrazolium-5-carboxanilide inner salt, sodium salt     

依托咪酯通过调控LncRNA CDKN2B-AS1/miR-199a-5p表达抑制胶质瘤细胞增殖、迁移和侵袭

目的 探讨依托咪酯对胶质瘤细胞的增殖、迁移和侵袭的影响及其作用机制.方法 用不同浓度的依托咪酯处理胶质瘤细胞U251,采用四甲基偶氮唑蓝(MTT)检测依托咪酯对U251细胞增殖能力的影响;Transwell实验检测依托咪酯对U251细胞迁移及侵袭的影响;实时荧光定量-聚合酶链反应(qRT-PCR)检测胶质瘤组织中长链非...     

Tranilast inhibits the proliferation of human coronary smooth muscle cell through the activation of p21waf1

Restenosis after percutaneous transluminal coronary angioplasty (PTCA) occurs due to vascular smooth muscle cell proliferation and migration. Recently, tranilast, an anti-allergic drug, has been used for the prevention of restenosis after PTCA. To determine the molecular mechanism involved, the effect of tranilast on the proliferation of human coronary smooth muscle cells (SMCs) was investigated. Tranilast arrested the proliferation of human coronary SMCs at the G0/G1 phase of the cell cycle. In association with this inhibitory effect, tranilast increased p21waf1 and p53 tumor suppressor factor, and decreased cyclin-dependent kinase 2 (CDK2) activity. These results suggest that tranilast inhibits the proliferation of human coronary SMCs during restenosis after PTCA via an induction of p21waf1 and p53. Tranilast may thus allow us to prevent restenosis after PTCA by interfering with this mechanism.     

Newly developed transarterial chemoembolization material: CDDP-lipiodol suspension

Cis-Diamminedichloroplatinum (CDDP)-lipiodol suspension (CLS) was developed as a transarterial chemoembolization (TACE) material. The CLS was injected into the proper hepatic artery or distal branches of patients with hepatocellular carcinoma. Strong anticancer effects were observed. Plasma concentrations of total and filtrable CDDP following TACE were much lower than those following intravenous administration of CDDP solution. No major adverse complications were noted, presumably due to low CDDP concentrations in circulating plasma. The CLS appears to be an excellent TACE material.     

Markers of cell proliferation, apoptosis, and angiogenesis in thyroid adenomas: a comparative immunohistochemical and genetic investigation of functioning and nonfunctioning nodules.

OBJECTIVE: To perform (i) an immunohistochemical investigation of cell proliferation, apoptosis, angiogenesis, and malignancy markers in 15 functioning and 15 nonfunctioning thyroid adenomas, and in normal adjacent tissue, and (ii) a genetic analysis of thyroid-stimulating hormone receptor (TSH-r), Gsalpha, and RAS mutations in the same group of adenomas, in order to describe their expression within tissues and to correlate them with the hormonal functioning. DESIGN: Thirty patients who underwent surgery for a solitary thyroid nodule were included in the study. Adenomas and normal adjacent tissues were evaluated by immunohistochemistry using the following antibodies: MIB-1 for proliferative activity, bcl-2 and mutant p53 for apoptosis control, vascular endothelial growth factor-A (VEGF-A) for angiogenic activity, and galectin-3 as a marker for malignancy. To calculate microvascular density, "hot spots" were selected and defined by cells positive for CD34 staining. Genetic analysis for TSH-r, Gsalpha, and H-, K-, and N-RAS mutations was performed on adenoma specimens. MAIN OUTCOMES: Our results evidenced that a proportion of both functioning and nonfunctioning adenomas showed immunohistochemical phenotypes similar to normal adjacent tissue. No differences were found between functioning and nonfunctioning thyroid adenomas with regard to the expression of markers associated to angiogenesis (VEGF-A, microvascular density) and apoptosis control (mutant p53, bcl-2). All adenomas resulted negative for galectin-3 immunostaining. MIB-1 was the only marker showing a substantial difference of expression between the two groups of adenomas. TSH-r mutations were found in 12 out of 15 functioning adenomas, whereas the absence of Gsalpha and H-, K-, and N-RAS mutations was demonstrated in all adenomas. CONCLUSIONS: Our data suggest that the differences between functioning and nonfunctioning thyroid adenomas are restricted to the genetic mutations of the TSH-r, to the hormonal status of tumors, and to the proliferative activity, not involving markers of apoptosis control and angiogenesis.     

初步探索DIM-C-pPhOH（ NR4A1拮抗剂）对胶质瘤细胞增殖、迁移及侵袭的抑制作用及作用机制

目的探索DIM-C-pPhOH（NR4A1拮抗剂）对胶质瘤细胞增殖、迁移、侵袭的抑制作用及其作用机制，以及对于胶质瘤小鼠模型生存期及肿瘤生长的影响。 方法不同浓度DIM-C-pPhOH处理胶质瘤细胞系（GL261、U251、U118）48 h后，用CellTiter法检测细胞活性及IC₅₀；采用划痕实验和3D-invasion实验检测DIM-C-pPhOH对U251细胞系侵袭迁移作用的影响；通过腹腔注射该化合物治疗小鼠胶质瘤模型，观察DIM-C-pPhOH对于小鼠胶质瘤生长以及生存期的影响。 结果U251、GL261和U118胶质瘤细胞系经DIM-C-pPhOH处理48 h后，细胞活性随药物浓度增加显著降低，IC₅₀分别为5.76、6.87、9.93 μmol/L；U251细胞系经10 μmol/L DIM-C-pPhOH处理后其迁移和侵袭能力显著下降；同时DIM-C-pPhOH可以抑制由TGF-β诱导的NR4A1出核表达；小鼠胶质瘤模型中DIM-C-pPhOH治疗组生存期延长，肿瘤生长受到抑制。蛋白免疫印迹显示DIM-C-pPhOH可以明显抑制Akt、P70S6K蛋白表达，通过抑制PI3K/Akt/mTOR/p70s6k信号通路，诱导细胞自噬发生。 结论DIM-C-pPhOH可以抑制胶质瘤的迁移及侵袭能力，延长小鼠胶质瘤模型的生存期并抑制肿瘤生长，作用机制可能与DIM-C-pPhOH诱导细胞发生自噬有关。     

Hepatocyte senescence in end-stage chronic liver disease: a study of cyclin-dependent kinase inhibitor p21 in liver biopsies as a marker for progression to hepatocellular carcinoma.

BACKGROUND: Histologic markers to predict hepatocellular carcinoma (HCC) include small cell change and dysplastic nodules. Hepatocyte senescence is noted in chronic liver disease and may or may not be important in progression to HCC. AIM: The study was undertaken to compare standard histologic features of chronic liver disease as well as markers of senescence and proliferation in two groups of biopsies from patients followed for at least a year. Methods: Standard histologic evaluation of necroinflammatory activity, fibrosis, steatosis, and iron, internationally accepted criteria of dysplasia, and immunohistochemical markers for proliferation and hepatocyte senescence were compared in 47 liver biopsies from noncholestatic chronic liver disease patients who subsequently either underwent transplant (the Control group, n=19) or had biopsy-proven (HCC group, n=28) over a similar time period of 34.9 months (mean) and 42.5 months (mean) respectively. RESULTS: Both groups were predominantly men; the MELD score was higher, and mean age was less in the Control group (46.9 vs 53.8 years, P=0.01). Small cell change was not significantly different in the biopsies between the two groups; neither were grade, stage (Ishak scores), nor presence or location of iron. Steatosis was more common in the group that subsequently developed HCC (P=0.04). The MIB-1 proliferation index was greater in the biopsies from the Control group. The senescence marker p21, and the ratio of p21:MIB-1 were not statistically different between the two groups. However, a Spearman's rank correlation showed a linear correlation of p21/MIB-1 with a greater amount of dyplasia in the explant livers of Controls. CONCLUSIONS: These findings suggested the Control groups' livers maintained effective removal of cells from the cell cycle by overexpression of p21 and, while not 'protected' from significant involvement by dysplasia, may have been precluded from development of HCC.     

A peptide derived from the non-receptor-binding region of urokinase plasminogen activator inhibits glioblastoma growth and angiogenesis in vivo in combination with cisplatin

The urokinase plasminogen activator system is involved in angiogenesis and tumor growth of malignant gliomas, which are highly neovascularized and so may be amenable to antiangiogenic therapy. In this paper, we describe the activity of A6, an octamer capped peptide derived from the non-receptor-binding region of urokinase plasminogen activator. A6 inhibited human microvascular endothelial cell migration but had no effect on the proliferation of human microvascular endothelial cells or U87MG glioma cells in vitro. In contrast, A6 or cisplatin (CDDP) alone suppressed subcutaneous tumor growth in vivo by 48% and 53%, respectively, and, more strikingly, the combination of A6 plus CDDP inhibited tumor growth by 92%. Such combination treatment also greatly reduced the volume of intracranial tumor xenografts and increased survival of tumor-bearing animals when compared with CDDP or A6 alone. Tumors from the combination treatment group had significantly reduced neovascularization, suggesting a mechanism involving A6-mediated inhibition of endothelial cell motility, thereby eliciting vascular sensitivity to CDDP-mediated toxicity. These data suggest that the combination of an angiogenesis inhibitor that targets endothelial cells with a cytotoxic agent may be a useful therapeutic approach.     

Growth suppression induced by wild-type p53 protein is accompanied by selective down-regulation of proliferating-cell nuclear antigen expression.

The p53 gene is a frequent target of mutation in a wide variety of human cancers. Previously, it was reported that conditional expression of wild-type p53 protein in a cell line (GM47.23) derived from a human glioblastoma multiform tumor had a negative effect on cell proliferation. We have now investigated the effect that induction of wild-type p53 protein in this cell line has on the expression of the proliferating-cell nuclear antigen gene. The proliferating-cell nuclear antigen gene encodes a nuclear protein that is an auxiliary factor of DNA polymerase delta and part of the DNA replication machinery of the cell. We show that inhibition of cell cycle progression into S-phase after induction of wild-type p53 protein is accompanied by selective down-regulation of proliferating-cell nuclear antigen mRNA and protein expression.     

Prognostic value of cell cycle regulatory proteins in muscle-infiltrating bladder cancer

Purpose The aims of this study were to investigate the expression levels of proteins involved in cell cycle regulation in specimens of bladder cancer and to correlate them with the clinicopathological characteristics, proliferative activity and survival.Methods Eighty-two specimens obtained from patients affected by muscle-invasive bladder cancer were evaluated immunohistochemically for p53, p21 and cyclin D1 expression, as well as for the tumour proliferation index, Ki-67. The statistical analysis included Kaplan–Meier curves with log-rank test and Cox proportional hazards models.Results In univariate analyses, low Ki-67 proliferation index (P = 0.045) and negative p21 immunoreactivity (P = 0.04) were associated to patient’s overall survival (OS), but in multivariate models p21 did not reach statistical significance. When the combinations of the variables were assessed in two separate multivariate models that included tumour stage, grading, lymph node status, vascular invasion and perineural invasion, the combined variables p21/Ki-67 or p21/cyclin D1 expression were independent predictors for OS; in particular, patients with positive p21/high Ki-67 (P = 0.015) or positive p21/negative cyclin D1 (P = 0.04) showed the worst survival outcome.Conclusions Important alterations in the cell cycle regulatory pathways occur in muscle-invasive bladder cancer and the combined use of cell cycle regulators appears to provide significant prognostic information that could be used to select the patients most suitable for multimodal therapeutic approaches.     

Radiation sensitivities in various anticancer-drug-resistant human lung cancer cell lines and mechanism of radiation cross-resistance in a cisplatin-resistant cell line

Summary To determine whether there exists cross-resistance between anticancer drugs and radiation, six drug-resistant human lung cancer cell lines and their parental cell lines were examined for radiosensitivity using a growth-inhibition assay. Only one cisplatin-resistant cell line, PC-9/CDDP, showed cross-resistance to radiation. The other three cisplatin-resistant cell lines (PC-7/CDDP, PC-4/CDDP, and H69/CDDP), an etoposide-resistant cell line (H69/VP) and a camptothecin-resistant cell line (PC-7/CPT) did not show cross-resistance to radiation. To analyze the mechanism of radiation resistance in PC-9/CDDP cells, the formation and repair of radiation-induced DNA single-strand breaks (ssb) and double-strand breaks (dsb) were examined by alkaline elution and neutral elution respectively. Although the formation of DNA ssb and repair of both DNA ssb and DNA dsb were the same for both cell lines, the formation of DNA dsb in PC-9/CDDP cells was significantly less than those in PC-9 cells. Measurement of intracellular glutathione content in all of the cell lines revealed that only PC-9/CDDP cells had a significant increase of glutathione content compared to the parental cells. Buthionine sulfoximine treatment of PC-9/CDDP cells caused an increase of DNA dsb to the same levels as in PC-9 cells after irradiation and caused a complete radiosensitization. These results indicate that cross-resistance to radiation in drug-resistant cells in a rare phenomenon, and increased glutathione content may play a crucial role in the emergence of cross-resistance to radiation in the drug-resistant cells.Abbreviations Cisplatin cis-diamminedichloroplatinum(II) - VP-16 etoposide - GSH glutathione - FBS fetal bovine serum - BSO L-buthionine (S, R)-sulfoximine - ssb single-strand breaks - dsb doublestrand breaks     

Epithelial cell turnover, p53 and bcl-2 protein expression during oncogenesis of early and advanced gastric cancer in a Western population

OBJECTIVES: To investigate epithelial cell turnover alterations, and p53, bcl-2 protein expression during development of early and advanced gastric cancer in a Western population. METHODS: We investigated cell apoptosis and proliferation rates, p53 and bcl-2 protein expression in 17 early and 34 advanced gastric carcinomas and in the adjacent non-dysplastic mucosa. Cell proliferation, p53 and bcl-2 expression were detected immunohistochemically using MIB-1, anti-p53 and anti-bcl-2 monoclonal antibodies. Apoptosis was measured by TUNEL. The rate of the positive stained cells (labelling index) was count using image analysis technique. RESULTS: No difference was observed of either apoptotic (10 vs. 11) or proliferation (35 vs. 25) index between early and advanced cancers. However, the apoptotic index was significantly higher in intestinal type advanced tumors. While both apoptotic and proliferation indices were significantly higher in tumors than in the adjacent mucosa, no difference was observed of either apoptotic (2 vs. 2) or proliferation (8 vs. 13) index between the tissues adjacent to early and advanced tumors. p53 protein expression was significantly higher in advanced cancers (7 vs. 5, p=0.001) and in the non-dysplastic tissue adjacent to advanced tumors (3.5 vs. 2, p=0.001). bcl-2 labelling index was significantly higher in the mucosa adjacent to advanced carcinomas (15 vs. 5, p=0.016) but this difference did not reach significance in the tumors (20 vs. 15, p=0.37). CONCLUSIONS: Our data indicate similar cell turnover during tumorigenesis of early and advanced cancer. p53 and bcl-2 protein accumulation is more intense in gastric mucosa adjacent to advanced tumors and p53 immunoreactivity peaks in advanced carcinomas.