甲基莲心碱逆转人胃癌细胞株多药耐药性

目的:研究新的钙阻断剂甲基莲心碱(Nef)对耐长春新碱(VCR)人胃癌细胞多药耐药性(MDR)的逆转作用及其机制。方法:采用MTT比色法测定药物的细胞毒作用,SP法免疫细胞化学及流式细胞术检测Nef对人胃癌细胞多药耐药性相关蛋白(MRP)表达的影响。结果:①在10μmol/L的浓度下,Nef对SGC7901及SGC7901/VCR无显著细胞毒作用;②2.5、5、10μmol/LNef能使VCR对SGC7901/VCR细胞的IC50从2.32μg/ml依次下降至0.340、0.128、0.053μg/ml,逆转倍数分别为6.8、18.1、43.8。在浓度为10μmol/L时,逆转活性较VRP为高(P<0.01);③SGC7901/VCR细胞较SGC7901细胞高表达MRP,经Nef处理后,SGC7901/VCR细胞MRP表达明显下降。表明Nef能下调SGC7901/VCR细胞MRP的表达。结论:甲基莲心碱在体外能逆转耐长春新碱人胃癌细胞(SGC7901/VCR)的多药耐药性。其机制可能与下调MRP的表达有关。     

三氧化二砷逆转人胃癌细胞SGC7901/ADR耐药性的作用机制

Objective: To investigate the reversal effect of arsenic trioxide (As2O3) on the multidrug resistance of human gastric tumor SGC7901/ADR cell line to adriamycin (ADM) and its reversal mechanisms. Methods: The non-cytotoxic concentration of As2O3 and the sensitivity of SGC7901/ADR cells to ADM were detected by MTT assay. The drug concentration and P-gp function of SGC7901/ADR cells were measured with flow cytometry (FCM), and the impacts of As2O3 on the GST-π and TopoⅡ expressions of SGC7901/ADR cells were analyzed by immunohistochemical method. Results: As2O3 at 0.4 to 0.8 μmol/Lconcentrations were not significantly cytotoxic to SGC7901/ADR cells. As2O3 at 0.8 μmol/L could improve the sensitivity of SGC7901/ADR cells to ADM via inhibiting P-gp function, down-regulating GST-π expression and increasing the intracellular accumulation of ADM in SGC7901/ADR cells. Conclusion: As2O3 can reverse partly the drug-resistance of SGC7901/ADR cells to ADM, which may be related with inhibiting the P-gp function and down-regulating GST-π expression.     

Silibinin reverses drug resistance in human small-cell lung carcinoma cells

Small-cell lung carcinoma (SCLC) has a dismal prognosis in part because of multidrug resistance (MDR). Silibinin is a flavonolignan extracted from milk thistle (Silybum marianum), extracts of which are used in traditional medicine. We tested the effects of silibinin on drug-sensitive (H69) and multi-drug resistant (VPA17) SCLC cells. VPA17 cells did not show resistance to silibinin (IC₅₀ = 60 μM for H69 and VPA17). Flow cytometry analysis after incubation in 30 μM silibinin showed no changes in cell cycle phases in VPA17 or H69 cells compared with untreated cells. Silibinin (30 μM) incubation was pro-apoptotic in VPA17 cells after >3 days, as measured by ELISA of BUdR labeled DNA fragments. Apoptosis was also indicated by an increase in caspase-3 specific activity and decrease in survivin in VPA17 MDR cells. VPA17 cells had increased Pgp-mediated efflux of calcein acetoxymethyl ester (calcein AM); however, this was inhibited in cells pre-incubated in silibinin for 5 days. Pre-incubation of VPA17 cells in 30 μM silibinin for 5 days also reversed resistance to etoposide (IC₅₀ = 5.50 to 0.65 μM) and doxorubicin (IC₅₀ = 0.625 to 0.035 μM). The possible synergistic relationship between silibinin and chemotherapy drugs was determined by exposure of VPA17 cells to 1:1 ratios of their respective IC₅₀ values, with serial dilutions at 0.25 to 2.0 × IC₅₀ and calculation of the combination index (CI). Silibinin and etoposide showed synergism (CI = 0.46 at ED50), as did silibinin and doxorubicin (CI = 0.24 at ED50). These data indicate that in SCLC, silibinin is pro-apoptotic, reverses MDR and acts synergistically with chemotherapy drugs. Silibinin, a non-toxic natural product may be useful in the treatment of drug-resistant SCLC.     

宫颈癌侧群细胞化疗耐受性的体外研究

目的：观察化疗药物干预对人宫颈癌细胞系Hela侧群细胞和非侧群细胞中ABCG2、ABCC2基因表达变化的影响,探讨两群细胞化疗耐受性的差异。方法：Hoechst 33342免疫荧光染色与流式细胞术（ FACS）相结合分选宫颈癌细胞系Hela中的侧群细胞和非侧群细胞。给予顺铂干预,利用RT-PCR观察两群细胞化疗前后ABCG2、ABCC2基因的表达差异,以及细胞凋亡情况。结果：与非侧群细胞相比,侧群细胞 ABCG2、ABCC2基因表达更高,但差异不明显;顺铂干预后,两组细胞ABCG2、ABCC2基因表达均有升高,组间比较侧群细胞中ABCG2、ABCC2明显高于非侧群细胞,差异有统计学意义;侧群细胞对于IC50附近两个顺铂浓度0.95μg/ml和1.9μg/ml的耐受能力较好,细胞没有因药物的加入而大量凋亡,细胞凋亡率反而略有下降。非侧群细胞对于IC50附近0.95μg/ml和1.9μg/ml顺铂浓度的耐受能力较差,细胞大量凋亡。结论：来源于宫颈癌Hela细胞中的侧群细胞相对于非侧群细胞顺铂化疗耐受性更强,这种化疗耐受可能与侧群细胞 ABCG2、ABCC2的高表达抑制细胞凋亡有关。     

ABCG2基因在胃癌组织中的表达(英文)

Objective:The aim of this study was to investigate the expression of ABCG2 in human gastric carcinoma and its clinical significance.Methods:Expression of ABCG2 was examined with immunohistochemical technique in the specimens from 45 gastric carcinoma tissues and 30 surrounding normal tissues.The mRNA expression of ABCG2 was measured by RT-PCR and real-time quantitative PCR in 30 cases of gastric carcinoma and normal gastric mucosa, respectively.Results:ABCG2 expression was observed in 28 of 45(62.2%) cases ...     

长链非编码RNA 与胃癌诊断预后及耐药性研究进展*

长链非编码RNA（longnon-codingRNA ,lncRNA）是一组长度超过200bp的非编码RNA。其缺少完整蛋白编码功能,具有调控基因表达作用。近年来研究发现,lncRNA 与胃癌的诊断、预后及耐药性密切相关。本文结合国内外最新报道,对ln ?cRNA 在胃癌的诊断,预后及耐药性方面的研究进展做一综述。      

Novel plant triterpenoid drug amooranin overcomes multidrug resistance in human leukemia and colon carcinoma cell lines

Amooranin (AMR), a plant terpenoid, isolated from Amoora rohituka, was investigated for its ability to overcome multidrug resistance in human leukemia and colon carcinoma cell lines. AMR IC(50) values of multidrug-resistant leukemia (CEM/VLB) and colon carcinoma (SW620/Ad-300) cell lines were higher (1.9- and 6-fold) than parental sensitive cell lines (CEM and SW620). AMR induced G(2)+M phase-arrest during cell cycle traverse in leukemia and colon carcinoma cell lines and the percentage of cells in G(2)+M phase increased in a dose-dependent manner. Coincubation of tumor cells with both DOX and AMR reversed DOX resistance in 104-fold DOX-resistant CEM/VLB and 111-fold DOX-resistant SW620/Ad-300 cell lines with a dose modification factor of 50.9 and 99.6, respectively. Flow cytometric assay showed that AMR causes enhanced cellular DOX accumulation in a dose-dependent manner. AMR inhibits photolabeling of P-glycoprotein (P-gp) with [(3)H]-azidopine and the blocking effect enhanced with increasing concentrations of AMR. Our results show that AMR competitively inhibits P-gp-mediated DOX efflux, suggestive of a mechanism underlying the enhanced DOX accumulation and reversal of multidrug resistance by AMR.     

Transfection of interleukin-8 increases angiogenesis and tumorigenesis of human gastric carcinoma cells in nude mice

The growth and spread of tumour cells depends on adequate vasculature. We have previously reported that the expression of interleukin-8 (IL-8) directly correlates with the vascularity of human gastric carcinomas. To provide evidence for a causal role of IL-8 in angiogenesis and tumorigenicity of human gastric cancer, we used the lipofectin method to stably transfect the human TMK-1 gastric carcinoma cells (low endogenous IL-8) with an IL-8 expression vector or control vector. Transfection with IL-8 did not affect the proliferation of cultured cells, yet the culture supernatants of the transfected (but not control) cells stimulated proliferation of human umbilical vein endothelial cells. The IL-8-transfected and control cells were injected into the gastric wall of nude mice. IL-8-transfected cells produced rapidly growing, highly vascular neoplasms as compared to control cells. These results provide direct evidence for the role of IL-8 in the angiogenesis and tumorigenicity of human gastric carcinomas.     

胃癌、食管癌肿瘤耐药标志物P-gP、HSP表达的研究

目的　通过检测胃、食管肿瘤耐药标志物P gP、HSP ,进一步了解胃、食管恶性肿瘤细胞耐药机制。方法　对 1997年初至 1999年底 6 6例胃、食管癌手术切除标本 ,采用S P免疫组化方法检测肿瘤耐药标志物P gP、HSP的阳性表达率。结果　P gP、HSP在胃、食管癌组织中均有阳性表达 ,总阳性率分别为 39.39%和 5 3.30 %,且高分化组阳性表达率明显高于低分化组 (P <0 .0 5 )。结论　P gP、HSP两种耐药标志物在胃癌、食管癌组织中高表达与肿瘤耐药有关 ,临床医生应重视检测P gP、HSP ,以便指导化疗方案的选择。     

人yrdc基因表达促进了胃癌细胞的增殖

Objective  

The aim of the research was to study the function of human yrdC gene in the gastric carcinoma cells.     

Identification of genes associated with platinum drug sensitivity and resistance in human ovarian cancer cells

Platinum-based chemotherapeutic regimens are ultimately unsuccessful due to intrinsic or acquired drug resistance. Understanding the molecular basis for platinum drug sensitivity/resistance is necessary for the development of new drugs and therapeutic regimens. In an effort to identify such determinants, we evaluated the expression of approximately 4000 genes using cDNA microarray screening in a panel of 14 unrelated human ovarian cancer cell lines derived from patients who were either untreated or treated with platinum-based chemotherapy. These data were analysed relative to the sensitivities of the cells to four platinum drugs (cis-diamminedichloroplatinum (cisplatin), carboplatin, DACH-(oxalato)platinum (II) (oxaliplatin) and cis-diamminedichloro (2-methylpyridine) platinum (II) (AMD473)) as well as the proliferation rate of the cells. Correlation analysis of the microarray data with respect to drug sensitivity and resistance revealed a significant association of Stat1 expression with decreased sensitivity to cisplatin (r=0.65) and AMD473 (r=0.76). These results were confirmed by quantitative RT-PCR and Western blot analyses. To study the functional significance of these findings, the full-length Stat1 cDNA was transfected into drug-sensitive A2780 human ovarian cancer cells. The resulting clones that exhibited increased Stat1 expression were three- to five-fold resistant to cisplatin and AMD473 as compared to the parental cells. The effect of inhibiting Jak/Stat signalling on platinum drug sensitivity was investigated using the Janus kinase inhibitor, AG490. Pretreatment of platinum-resistant cells with AG490 resulted in significant increased sensitivity to AMD473, but not to cisplatin or oxaliplatin. Overall, the results indicate that cDNA microarray analysis may be used successfully to identify determinants of drug sensitivity/resistance and future functional studies of other candidate genes from this database may lead to an increased understanding of the drug resistance phenotype.     

胃癌中神经内分泌细胞的临床病理学意义

 本文应用铬粒素A（CgA）、胃泌素（GAS）、生长抑素（SS）及5-羟色胺（5-HT）对120例普通型胃癌用免疫组化SP法标记其神经内分泌细胞。结果表明：四种激素抗体检测，以CgA最敏感、阳性率最高为31.7%;高分化腺癌CgA阳性率显着高于低分化和未分化癌（P<0.05）,但高分化腺癌CgA阳性病例以（+）为主，未分化癌以（++）为主；而SS.5HT的阳性率，高、低分化腺癌均高于未分化癌（P>0.05）.CgA及5-HT阳性病例淋巴结转移率高于阴性病例（P<0.05）,CgA（++）病例术后生存期明显短于CgA（+）及CgA（-）者（P<0.05）,GAS、5-HT及SS阳性与阴性病例术后生存期无显着差异。     

MicroRNA let - 7f 对胃癌细胞株 SGC7901 / ADR 耐药性的影响

目的：通过检测胃癌细胞株SGC7901及其阿霉素耐药细胞株SGC7901/ADR中microRNA let-7f的表达差异,探讨let-7f表达与胃癌细胞对ADR耐药的关系.方法：通过实时荧光定量PCR比较SGC7901/ADR与SGC7901两种细胞中 let-7f表达水平的差异;MTT法检测SGC7901,SGC7901/ADR及转染let-7f mimic后SGC7901/ADR的药物敏感性;流式细胞仪检测细胞凋亡;Western Blot检测凋亡相关分子Bcl-2和Caspase-3蛋白表达情况.结果：qRT-PCR结果显示,let-7f在SGC7901/ADR细胞中的表达较在SGC7901中的表达显著降低（ P＜0.05）.MTT法结果显示SGC7901与SGC7901/ADR两种细胞阿霉素的半数抑制浓度（IC50）分别为（0.95 ±0.08）g/L和（5.40 ±0.28）g/L.SGC7901/ADR细胞转染let-7f mimic后,let-7f表达显著上调,并且对阿霉素的IC50明显降低（ P＜0.05）.凋亡检测结果显示,转染let-7f mimic后,SGC7901/ADR细胞凋亡率明显增加（ P＜0.05）.Western Blot结果表明相较于转染let-7f negative control（NC）组,转染let-7f mimic组cleaved-Caspase-3表达显著降低（P＜0.05）,而两组中的Bcl-2表达水平无差异.结论：let-7f在胃癌阿霉素耐药细胞株SGC7901/ADR中的表达显著降低,逆转let-7f表达可增加其对阿霉素敏感性,并诱导其凋亡.     

Anti-stromal therapy with imatinib inhibits growth and metastasis of gastric carcinoma in an orthotopic nude mouse model

Recent studies have revealed that platelet-derived growth factor (PDGF) plays a role in promoting progressive tumor growth in several organs; however, whether PDGF plays such a role in gastric carcinoma is undetermined. We examined whether inhibition of PDGF receptor (PDGF-R) tyrosine kinase signaling by imatinib affects tumor growth and metastasis in an orthotopic nude mouse model of human gastric carcinoma. TMK-1 human gastric carcinoma cells were injected into the gastric wall of nude mice. Groups of mice (n = 10 each) received sterile water (control), low-dose imatinib (50 mg/kg/day), high-dose imatinib (200 mg/kg/day), cancer chemotherapeutic agent irinotecan (5 mg/kg/week), or imatinib (50 mg/kg/day or 200 mg/kg/day) and irinotecan (5 mg/kg/week) in combination for 28 days. Tumor growth and metastasis were assessed. Resected tumors were analyzed immunohistochemically. Carcinoma-associated fibroblasts, pericytes and lymphatic endothelial cells in stroma expressed high levels of PDGF-R; carcinoma cells did not. Treatment with imatinib alone did not inhibit tumor growth and metastasis; however, treatment with irinotecan alone or combined with imatinib significantly inhibited tumor growth. Only treatment with high-dose imatinib and irinotecan in combination inhibited lymph node and peritoneal metastases. Immunohistochemically, only imatinib alone or in combination with irinotecan was shown to significantly decrease the stromal reaction, microvessel area and pericyte coverage of tumor microvessels. These effects were marked with high-dose imatinib. In conclusion, administration of PDGF-R tyrosine kinase inhibitor in combination with irinotecan appears to impair the progressive growth of gastric carcinoma by blockade of PDGF-R signaling pathways in stromal cells.     

E-cadherin expression in early gastric carcinoma and correlation with lymph node metastasis

OBJECTIVE: Abnormal expression of E-cadherin plays an important role in the differentiation and progression of gastric carcinoma. However, the relationship between molecular changes in E-cadherin and metastasis in early gastric carcinoma (EGC) is poorly understood. MATERIALS AND METHODS: Sixty cases of EGC with or without lymph node metastasis (30 node-positive cases and 30 node-negative cases) were investigated to evaluate hypermethylation status using bisulfate-MSP and immunohistochemistry using antibody against E-cadherin. RESULTS: Twenty-seven (45.0%) of 60 primary EGCs exhibited methylation in the CpG island of E-cadherin. Abnormal expression of E-cadherin was significantly correlated with patient age, tumor size, Lauren classification, differentiation, and lymph node metastasis. Using multiple logistic regression analysis, two factors were independent, statistically significant parameters associated with lymph node metastasis: abnormal expression of E-cadherin (risk ratio, 2.62; 95% confidence interval, 0.917-7.457; P < 0.05) and lymphatic invasion (risk ratio, 8.11; 95% confidence interval, 1.612-40.766; P < 0.05). CONCLUSION: Our results suggest that methylation of E-cadherin is a frequent, early event in gastric carcinoma progression, and is correlated significantly with downregulated E-cadherin expression. Inactivation of E-cadherin might be involved in metastasis in EGC and play an important role in microscopic differentiation.