Expression of Proapoptotic Genes for Cancer Therapy

描述（由申请人提供）： 毒性作用是大多数抗癌疗法的主要缺点，也是患者最担心的问题。因此，我们的目标是开发基于生物作用机制的癌症治疗技术，广泛适用，但毒性最小，使治疗更有效，毒性更小。这些研究的目的是评估人类Bax和人类肿瘤坏死因子相关凋亡诱导配体（TRAIL）基因在人类端粒酶逆转录酶（hTERT）启动子驱动下表达时的治疗和毒性作用，并制定更好的策略以获得最佳治疗效果。待测试的假设是Bax和/或TRAIL基因的高肿瘤特异性表达将消除肿瘤细胞，但使正常细胞免于其毒性作用。我们证明了直接转移TRAIL或Bax基因在p53敏感和p53耐药肿瘤细胞系中产生抗肿瘤作用，并且hTERT启动子能够防止Bax或TRAIL基因的毒性作用而不损害其抗肿瘤活性。此外，还构建了从hTERT启动子表达Bax或TRAIL基因的单双顺反子腺病毒载体，并对其功能进行了表征。正在进行的研究的初步数据表明，这些载体在治疗癌症方面可能有效，而且毒性最低。然而，目前尚不清楚的是（1）。对腺病毒载体介导的促凋亡基因治疗产生耐药性，如果是这样，可能的机制是什么，耐药性可以被克服; 2）.将膜凋亡基因（如Bax）与膜凋亡基因（如TRAIL）组合改善了治疗效果，特别是在对常规疗法有抗性的癌症中;和3）。hTERT-TRAIL和hTERTBax载体可用于治疗已建立的转移性肿瘤，这些肿瘤在体内对化疗具有抗性，并且如果有治疗相关的毒性作用，则治疗相关的毒性作用是什么。这项建议旨在解决这些未知数。这些研究的成功将为难治性转移性疾病带来新的治疗方法。它也将提供深入了解机制的抵抗细胞凋亡诱导的癌细胞。

DESCRIPTION (provided by applicant): Toxic effects are the major drawback of most anticancer therapeutics and are in the top list of patients' worries. Therefore, our goal is to develop technology for cancer treatment that is based on biological mechanisms of action, broadly applicable, and yet minimally toxic so that the treatment will be more effective and less toxic. The goals of the proposed studies are to evaluate the therapeutic and toxic effects of human Bax and human tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) genes when their expression is driven by the human telomerase reverse transcriptase (hTERT) promoter and to develop better strategies for optimal therapeutic effects. The hypothesis to be tested is that the high tumor-specific expression of the Bax and/or TRAIL genes will eliminate tumor cells but spare normal cells their toxic effects. We demonstrated that direct transfer of the TRAIL or Bax gene resulted in antitumor effects in both p53-sensitive and p53-resistant tumor lines and that hTERT promoter was able to prevent toxic effects of the Bax or TRAIL gene without compromising their antitumor activities. Moreover, single, bicistronic adenoviral vectors expressing the Bax or TRAIL gene from the hTERT promoter were also constructed and their functionality characterized. Preliminary data from studies in progress have shown that these vectors are potentially effective in the treatment of cancers and that they are minimally toxic. Yet, what remains unknown is whether 1). resistance develops to adenovector-mediated proapoptotic gene therapy and, if so, what the possible mechanisms are and the resistance can be overcome the resistance; 2). combining mitochondrion apoptotic genes (such as Bax) with membrane-apoptotic genes (such as TRAIL) improves therapeutic effects, especially in cancers that are resistant to conventional therapy; and 3). hTERT-TRAIL and hTERTBax vectors can be used to treat established metastatic tumors that are resistant to chemotherapy in vivo and what the treatment-related toxic effects are, if any. This proposal is designed to address these unknowns. Success of the proposed studies will lead to new therapeutics for refractory metastatic disease. It will also provide insight into mechanisms of resistance to apoptosis induction in cancer cells.