Radioenhancement by cisplatin with accelerated fractionated radiotherapy in a human tumour xenograft

The aim of the present study was to investigate whether cisplatin would enhance the radioresponse of a human tumour xenograft when given in different schedules combined with accelerated fractionated radiation therapy. A human squamous carcinoma of the hypopharynx, FaDu, was grown in the thigh of athymic nude mice. Tumours were exposed to twice-daily 2-Gy fractions, applied 6 h apart over 2 weeks, 5 days a week, alone or combined with cisplatin given at maximally tolerated doses in three different schedules: (1) i.p. as a single bolus (SB) or (2) i.p. as a daily bolus at 30 min before the first daily radiation fraction or (3) s.c. as a continuous infusion through a mini-osmotic pump over 13 days, commencing 24 h prior to the first daily radiation fraction. The end point for the study was tumour growth delay (TGD), calculated as the difference between the delay in regrowth to 200% of the initial tumour size in treated versus control mice. SB cisplatin plus radiation showed only an additive effect on TGD, whereas daily-bolus and continuous-infusion cisplatin demonstrated a greater than additive effect when combined with accelerated fractionated radiation in this human tumour model. Cisplatin appears to be especially beneficial as a radiation enhancer when given throughout the course of radiation. Received: 15 December 1996 / Accepted: 25 March 1997     

人胚食管异种移植和诱癌研究

［目的］探讨人胚食管在裸鼠体内的异种移植及苯并在诱癌。［方法］人胚食管移植至探鼠，移植的人胚食管用苯并芘诱癌，观察移植物1－4个月并取材进行光镜、电镜和免疫级化检查。［结果］人胚食管在裸鼠皮下可存活4个月以上。移植的人胚食管用苯并芘诱癌，2个月可出现浸润性鳞状上皮癌。其病变有粘膜上皮坏死脱落、再生、增生、乳头状瘤样增生、不典型增生、原位癌及浸润癌。［结论］苯并芘能诱发人食管上皮癌。实验结果将有助于食管癌病因和发病机理研究。     

Response of a multidrug-resistant human small-cell lung cancer xenograft to chemotherapy

Small-cell lung carcinomas (SCLC) are highly responsive to various chemotherapies. However only a minority of patients benefit from long survival. SCLC patients treated at the Institut Gustave Roussy received a combined chemotherapy (CCAV) including cisplatin, cyclophosphamide (Cpa), Adriamycin (doxorubicin; Adm) and vepeside (VP16). We report here the intrinsic sensitivity of a small-cell lung carcinoma, designated SCLC-6, grafted in nude mice. This xenografted tumour was derived from an untreated patient. The CCAV regimen given to the patient donor of the tumour sample resulted in a complete response followed by recurrence and death, 8 months after the initial cure. The expression of P-glycoprotein encoded by theMDR1 gene was detected with the C219 antibody on the membrane of SCLC-6 tumour cells. When given to SCLC-6-tumour-bearing nude mice, CCAV induced a strong inhibition of tumour growth (84% of growth inhibition, 20 days after start of the treatment), but no cure. Intensification of CCAV doses did not improve the response. The efficacy of individual agents of the CCAV, given at maximal tolerated doses was analysed. Only cisplatin (10 mg/kg) and Cpa (3×50 mg/kg) inhibited SCLC-6 growth (79% and 100% inhibition respectively), VP16 (3×24 mg/kg) was poorly efficient (42%) and Adm (10 mg/kg) not at all. Two-drug combinations such as cisplatin plus VP16 or cisplatin plus Cpa inhibited tumour growth (81% and 70%, respectively). Curiously, the efficacy of Cpa, given in combination with cisplatin was less than that of Cpa alone. Repeated treatments with CCAV administered to mice at each in vivo passage of the tumour induced a loss of chemosensitivity, which was observed until the ninth passage. An improvement of the therapeutic response was obtained by adding a headline reverser of multidrug resistance, verapamil (25 mg/kg), to CCAV (81% versus 63% inhibition). MDR1-related resistance appeared to play a role in the failure of SCLC-6 chemotherapy; frequent recurrences after treatment with cisplatin and Cpa, two drugs that are not recognized by the P-glycoprotein, indicated that other modes of resistance were simultaneously active.Abbreviations SCLC small-cell lung cancer - CCAV cyclophosphamiede (CPA)/cisplatin/Adriamycin (Adm)/vepeside (V)16)     

Adenovirus expressing p27kip1 suppresses growth of established esophageal carcinoma xenograffs

AIM: To investigate the growth suppression of adenovirus expressing p27kip1 on established esophageal tumors in nude mice.METHODS: Esophageal carcinoma xenografts in nude mice were established by tumor tissue mass transplantation. The successfully constructed recombinant adenoviral vectors carrying p27kip1 gene (Adp27kip1) were directly injected into the esophageal tumors in nude mice. Compared to control group, the growth curve of tumor was drawn and the growth inhibition rate of tumor was calculated. The histology of tumors was examined by hematoxylin and eosin (H&E) staining. The expression of p27kip1 and survivin was detected in tumors by immunohistochemical technique.RESULTS: The growth of tumors in gene therapy group with Ad-p27kip1 was obviously suppressed compared to control group (0.42±0.08 g vs 1.17±0.30 g, t=6.39,P＜0.01), the inhibition rate of tumor growth reached 64.1%. Pathological detection showed that the tumors in nude mice were poorly differentiated esophageal squamous carcinoma. In addition, the expression of p27kip1 was increased, while the expression of survivin was decreased in tumors after being transfected with Ad-p27kip1.CONCLUSION: p27kip1 gene therapy mediated by adenovirus vector has a significant inhibitory effect on esophageal carcinoma in vivo. Up-regulated p27kip1expression and down-regulated survivin expression may be its important mechanisms.     

双向调控Cox-2表达对人食管癌EC9706细胞裸鼠移植瘤放射敏感性的影响

目的 探讨上调和下调Cox-2基因表达对食管癌EC9706细胞裸鼠移植瘤放射敏感性的影响。方法 构建针对Cox-2基因的siRNA载体及Cox-2基因真核表达载体,通过脂质体转染技术将其转入食管癌EC9706细胞,G418筛选得到稳定转染细胞系。荧光定量RT-PCR和Western blot分别检测细胞中Cox-2 mRNA和Cox-2蛋白表达水平;裸鼠移植瘤实验检测上调和下调Cox-2表达联合X射线照射对食管癌的生长抑制作用。结果 Cox-2下调组食管癌EC9706细胞内Cox-2基因表达明显降低,Cox-2上调组明显升高。Cox-2下调组裸鼠移植瘤平均体积明显小于对照组(F=34.26,P<0.05);Cox-2上调组的瘤体平均体积大于对照组(F=26.38,P<0.05)。20 Gy γ射线照射后Cox-2下调组瘤体平均体积较照射前明显减小(F=16.35,P<0.05);而上调组裸鼠皮下种植瘤平均体积较照射前无明显变化。结论 下调Cox-2表达能抑制人食管癌EC9706细胞裸鼠移植瘤的生长,增强瘤体的放射敏感性,上调Cox-2表达则使肿瘤辐射抗拒。     

肝癌细胞不同制悬方法建立裸鼠移植瘤模型的比较

目的比较肝癌细胞不同制悬方法建立裸鼠皮下瘤及原位瘤模型,优选建模方法。方法将肝癌细胞分别采用PBS缓冲液(PBS组)、无血清DMEM溶液(DMEM组)和含10%血清的DMEM溶液(血清DMEM组)3种液体制悬后注入裸鼠皮下建立肝癌裸鼠皮下瘤模型,比较皮下瘤的体积、瘤重及成瘤率;将肝癌细胞分别采用PBS缓冲液(PBS组)、无血清DMEM溶液(DMEM组)和含10%血清的DMEM溶液(血清DMEM组)3种液体制悬后注入裸鼠肝脏建立肝癌裸鼠原位瘤模型,比较原位瘤的成瘤率。结果3组裸鼠皮下瘤模型的皮下瘤体积及瘤重相比,差异无统计学意义(P0.05),但是PBS组及DMEM组的成瘤率(90%和100%)明显高于血清DMEM组(40%),差异有统计学意义(P0.05);裸鼠原位瘤模型中PBS组的成瘤率(90%)明显高于DMEM组(40%)及血清DMEM组(20%),差异有统计学意义(P0.05)。结论采用PBS缓冲液或无血清DMEM溶液对肝癌细胞稀释制悬可以有效建立裸鼠皮下瘤模型,采用PBS缓冲液对肝癌细胞稀释制悬可以有效建立裸鼠原位瘤模型。     

Molecular determinants of susceptibility to oncolytic vesicular stomatitis virus in pancreatic adenocarcinoma

Background

M protein mutant vesicular stomatitis virus (M51R-VSV) has oncolytic properties against many cancers. However, some cancer cells are resistant to M51R-VSV. Herein, we evaluate the molecular determinants of vesicular stomatitis virus (VSV) resistance in pancreatic adenocarcinoma cells.

Methods

Cell viability and the effect of β-interferon (IFN) were analyzed using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay. Gene expression was evaluated via microarray analysis. Cell infectability was measured by flow cytometry. Xenografts were established in athymic nude mice and treated with intratumoral M51R-VSV.

Results

Four of five pancreatic cancer cell lines were sensitive to M51R-VSV, whereas Panc 03.27 cells remained resistant (81 ± 3% viability 72 h after single-cycle infection). Comparing sensitive MiaPaCa2 cells with resistant Panc 03.27 cells, significant differences in gene expression were found relating to IFN signaling (P = 2 × 10⁻⁵), viral entry (P = 3 × 10⁻⁴), and endocytosis (P = 7 × 10⁻⁴). MiaPaCa2 cells permitted high levels of VSV infection, whereas Panc 03.27 cells were capable of resisting VSV cell entry even at high multiplicities of infection. Extrinsic β-IFN overcame apparent defects in IFN-mediated pathways in MiaPaCa2 cells conferring VSV resistance. In contrast, β-IFN decreased cell viability in Panc 3.27 cells, suggesting intact antiviral mechanisms. VSV-treated xenografts exhibited reduced tumor growth relative to controls in both MiaPaCa2 (1423 ± 345% versus 164 ± 136%; P < 0.001) and Panc 3.27 (979 ± 153% versus 50 ± 56%; P = 0.002) tumors. Significant lymphocytic infiltration was seen in M51R-VSV–treated Panc 03.27 xenografts.

Conclusions

Inhibition of VSV endocytosis and intact IFN-mediated defenses are responsible for M51R-VSV resistance in pancreatic adenocarcinoma cells. M51R-VSV treatment appears to induce antitumor cellular immunity in vivo, which may expand its clinical efficacy.     

靶向性自杀基因治疗系统联合放射线治疗前列腺癌移植瘤的实验研究

目的初步判断针对整合素αv的靶向性自杀基因治疗系统(RGD4C AAVP HSV-TK/ GCV)是否能提高前列腺癌细胞株DU145移植瘤的放射效应。方法建立移植性前列腺癌细胞株DU145的裸鼠肿瘤模型48只。当位于每只裸鼠右大腿的肿瘤直径达6.0mm(5.8～6.3 mm)时,开始实验。实验共分成6组(每组8只),分别为对照组、单纯放射组、单纯RGD-4C AAVP HSV-TK/GCV组(RGD-4C组)、单纯AAVP HSV-TK/GCV组(无RGD-4C组)、RGD-4C AAVP HSV-TK/GCV联合放射组(XRT RGD4C组)和AAVP HSV-TK/GCV联合放射组(XRT 无RGD-4C组)。观察指标为肿瘤生长延迟时问(肿瘤从6.0 mm生长至12.0 mm所需时间)和肿瘤治愈情况。结果除5只在实验过程中死亡外,单纯放射组、RGD-4C组、无RGD-4C组各有1只和XRT RGD-4C组3只肿瘤被治愈。统计分析余下37只肿瘤生长情况发现,RGD-4C组、无RGD-4C组和单纯放射组的绝对延迟时间分别为(24.4±9.0)、(22.6±11.3)和(28.3±5.5)d;当RGD4C AAVP HSV-TK/GCV和AAVP HSV-TK/ GCV分别联合放射时,其绝对延迟时间分别为(64.7±23.8)和(35.4±9.6)d,而标准化的延迟时间则分别为(40.3±23.8)和(12.8±9.6)d,它们对放射的增益因子分别为1.42和0.45。结论针对整合素αv的靶向性自杀基因治疗系统RGD-4C AAVP HSV-TK/GCV能显著提高前列腺癌细胞株DU145移植瘤的放射效应,值得进一步研究。