OPTIMIZING CANCER CHEMOTHERAPY

尽管最近出现了令人兴奋的新型有效抗癌治疗药物（如脂质体药物、基因疗法、放射性标记抗体和毒素），但选择性地将足够浓度的这些新药物输送到构成大于1 - 2厘米的原发性和转移性癌症的肿瘤细胞中仍然是一个问题。我们建议全身热疗（WBH）可用于增加药物对肿瘤的递送和细胞毒性，同时保留正常组织。白冲天可以(i)增加肿瘤微血管的通透性，（ii）增加药物穿过肿瘤细胞膜的通道，（iii）刺激脂质体释放药物，（iv）通过增加药物与亚细胞靶点（如DNA）的相互作用增加直接细胞毒性，(v)抑制药物诱导的细胞损伤修复，（vi）破坏肿瘤微血管，从而限制肿瘤生长和转移。本建议侧重于（一）、（三）和（六）方面。具体目的是：A)利用白藜藜醇通过增加肿瘤微血管通透性来增加脂质体对肿瘤的递送；B)一旦脂质体在肿瘤中积累，就使用WBH来刺激并同步药物从脂质体中释放；C)将脂质体药物与两种旨在靶向微血管渗透性的热组分结合起来，并同步药物从脂质体释放，以平衡肿瘤控制的方式，通过直接内皮细胞毒性和微血管破坏来实现，与正常组织毒性。我们建议通过将精心设计的WBH和Doxil（多柔比星包裹在聚乙二醇的，空间稳定的脂质体中）的组合给予患有原位接种的MTLn3乳腺腺癌的Fischer大鼠来实现这一目标，这些肿瘤会自发转移到淋巴结。WBH将分为LL-WBH[长时间（6小时），低温（发烧样）39.5-40.0℃)whbh]和SH-WBH[短时间（1小时），高温（41.5℃）whbh]。为了确定这些治疗的疗效，我们将量化a)原发性和转移性肿瘤反应，b)正常组织反应，c)血浆药物浓度和肿瘤和正常组织中的药物积累随时间的变化（药代动力学），d)微血管通透性随时间的变化（VPF/VEGF和Flk-1/KDR水平），e)肿瘤微血管密度的时间过程。最终目标是开发一种治疗方法，该方法使用多种热组分，以及脂质体封装剂，针对肿瘤新生血管的两个不同方面，以增强肿瘤毒性。本提案中探讨的策略与许多创新的新治疗剂的交付直接相关。通过这种高温介导的多管齐下的治疗，我们希望能显著提高常见癌症患者的生存率和生活质量。

Despite the recent appearance of an exciting new arsenal of effective anti-cancer therapeutic agents (e.g. liposomal drugs, gene therapies, radiolabeled antibodies, and toxins), selectively delivering adequate concentrations of these new agents to tumor cells making up primary and metastatic cancers larger than 1 - 2 cm remains a problem. We propose that whoel body hyperthermia (WBH), can be used to increase both the delivery and cytotoxicity of drugs to tumors, while sparing normal tissue. WBH can (i) increase the permeability of tumor microvasculature, (ii) increase drug passage across the tumor cell membrane, (iii) stimulate release of drugs from liposomes, (iv) increase direct cytotoxicity by increasing the interaction of drugs with sub-cellular targets such as DNA (v) inhibit the repair of drug-induced cellular damage, and (vi) destroy tumor microvasculature, thereby limiting tumor growth and metastasis. This proposal focuses on aspects (i), (iii), and (vi). The specific aims are A) to use WBH to increase liposome delivery to tumor by increasing tumor microvascular permeability; B) to use WBH once liposomes have accumulated in the tumor to stimulate and synchronize release of drug from the liposome; C) to combine liposomal drug with two heat fractions designed to target microvessel permeability and synchronize drug release from the liposomes in a way which balances tumor control, achieved through direct endothelial cytotoxicity and microvessel destruction, with normal tissue toxicity. We propose to achieve this by administering carefully designed combinations of WBH and Doxil (doxorubicin encapsulated in a pegylated, sterically stabilized liposome) to Fischer rats bearing orthotopically inoculated MTLn3 mammary adenocarcinomas which spontaneously metastasize to lymph nodes. WBH will be administered as LL-WBH [long-duration (6h), low-temperature (fever-like) 39.5-40.0 C) WHB) and SH-WBH [short-duration (1 h), high temperature (41.5 C) WBH]. In order to determine the efficacy of these treatments, we will quantify a) primary and metastatic tumor response, b) normal tissue response, c) plasma drug concentration and drug accumulation in tumor and normal tissues as a function of time (pharmacokinetics), d) microvessel permeability as indicated by VPF/VEGF and Flk-1/KDR levels as a function of time, and e) the time course of tumor microvascular density. The ultimate goal is to develop a treatment, which uses multiple heat fractions, together with liposome-encapsulated agents, to target two different aspects of tumor neovasculature to enhance tumor toxicity. The strategy explored in this proposal has direct relevance to the delivery of many of the innovative, new therapeutic agents. Through such a hyperthermia-mediated multi- pronged attack, we hope to significantly increase the survival and quality of life of patients with common cancers.