Targeted tumoricidal bacteria

描述(申请人提供)：我们开发了一种有效的细菌癌症治疗策略，通过使用我们产生的鼠伤寒沙门氏菌营养缺陷性沙门氏菌来靶向存活的肿瘤组织，这些营养缺陷性细胞生长在肿瘤的存活和坏死区。然而，营养缺乏症严重限制了这些细菌在正常组织中的生长，使它们能够用于癌症治疗。本实验室培育的鼠伤寒沙门氏菌A1-R突变体对亮氨酸-精氨酸具有营养缺陷性，具有较强的抗肿瘤毒力。在体外，A1-R感染肿瘤细胞并导致核破坏。A1-R最初用于治疗已原位移植到裸鼠体内的转移性人类前列腺癌和乳腺癌。40%的治疗小鼠完全治愈，存活时间与未携带肿瘤的小鼠一样长。A1-R静脉注射。对原发骨肉瘤和肺转移的裸鼠有很高的疗效，尤其是对转移的抑制作用更强。A1-R还分别靶向于人胰腺癌和纤维肉瘤的腋窝淋巴结转移和裸小鼠纤维肉瘤的肺转移。细菌通过淋巴通道输送，以靶向淋巴结转移，并系统地通过尾静脉输送，以靶向肺转移。转移瘤在不需要化疗或任何其他治疗的情况下治愈。将A1-R应用于裸鼠的人胰腺癌原位移植瘤内。原发胰腺癌在没有额外化疗或任何其他治疗的情况下消退。当A1-R在裸鼠脾内给药时，也能有效地对抗胰腺癌肝转移。A1-R也被证明对原位小鼠模型的脊髓胶质瘤有效。这里描述的方法，其中细菌单一疗法有效地治疗原发和转移性肿瘤，与以前需要结合毒性化疗的细菌肿瘤治疗策略相比，是一个重大改进。目前的应用将开发使用鼠伤寒沙门氏菌A1-R在具有免疫能力的小鼠身上进行癌症的细菌治疗，作为通往临床的桥梁。本申请的具体目的是(1)确定鼠伤寒沙门氏菌A1-R在荷瘤C57免疫小鼠中的最大耐受量(MTD)。(2)确定鼠伤寒沙门氏菌A1-R在荷瘤小鼠体内的最佳给药剂量、给药途径和给药方案。沙门氏菌杀瘤能力的开发为肿瘤治疗的新范式提供了巨大潜力。 公共卫生相关性：我们已经开发了一种使用鼠伤寒沙门氏菌变种的细菌癌症治疗策略。这些细菌杀死癌细胞，但不能在正常组织中生长。我们的鼠伤寒沙门氏菌A1-R突变体在裸鼠模型中对许多癌细胞株具有抗肿瘤毒力。在体外，A1-R可以感染肿瘤细胞，并能引起迅速的核碎裂和细胞凋亡。在临床相关的小鼠模型中，A1-R被发现对转移性的人前列腺、乳腺和胰腺癌细胞系以及骨肉瘤、纤维肉瘤和胶质瘤细胞系有效。经治疗的小鼠通常完全治愈，存活时间与未携带肿瘤的小鼠一样长。这里描述的方法，其中细菌单一疗法有效地治疗原发和转移性肿瘤，与以前需要结合毒性化疗的细菌肿瘤治疗策略相比，是一个重大改进。目前的应用将在免疫活性小鼠模型中开发癌症的细菌疗法，作为进入临床试验的桥梁。沙门氏菌杀瘤能力的开发为肿瘤治疗的新范式提供了巨大潜力。

DESCRIPTION (provided by applicant): We have developed an effective bacterial cancer therapy strategy by targeting viable tumor tissue by using Salmonella typhimurium auxotrophs that we have generated which grow in viable as well as necrotic areas of tumors. However, the auxotrophy severely restricts growth of these bacteria in normal tissue enabling them to be used for cancer treatment. The S. typhimurium A1-R mutant, which is auxotrophic for leu-arg and has high antitumor virulence was developed in our laboratory. In vitro, A1-R infects tumor cells and causes nuclear destruction. A1-R was initially used to treat metastatic human prostate and breast tumors that had been orthotopically implanted in nude mice. Forty percent of treated mice were cured completely and survived as long as non-tumor-bearing mice. A1-R administered i.v. to the nude mice with primary osteosarcoma and lung metastasis was highly effective, especially against metastasis. A1-R was also targeted to both axillary lymph and popliteal lymph node metastasis of human pancreatic cancer and fibrosarcoma, respectively, as well as lung metastasis of the fibrosarcoma in nude mice. The bacteria were delivered via a lymphatic channel to target the lymph-node metastases and systemically via the tail vein to target the lung metastasis. The metastases were cured without the need of chemotherapy or any other treatment. A1-R was administered intratumorally to nude mice with an orthotopically-transplanted human pancreatic tumor. The primary pancreatic cancer regressed without additional chemotherapy or any other treatment. A1-R also was effective against pancreatic cancer liver metastasis when administered intrasplenically to nude mice. A1-R has also shown to be effective for spinal glioma in orthotopic mouse models. The approach described here, where bacterial monotherapy effectively treats primary and metastatic tumors, is a significant improvement over previous bacterial tumor-therapy strategies that require combination with toxic chemotherapy. The present application will develop bacterial therapy of cancer with S. typhimurium A1-R in immunocompetent mice as a bridge to the clinic. The specific aims of the present application are (1) Determine the maximum tolerated dose (MTD) of S. typhimurium A1-R in tumor-bearing C57 immunocompetent mice. (2) Determine the optimal dose, route and schedule of S. typhimurium A1-R in tumor-bearing immunocompetent mice. Exploitation of the tumor-killing capability of Salmonella has great potential for a new paradigm of cancer therapy. PUBLIC HEALTH RELEVANCE: We have developed a bacterial cancer therapy strategy using Salmonella typhimurium variants. These bacteria kill cancer cells but do not grow in normal tissue. Our S. typhimurium A1-R mutant has antitumor virulence against a number of cancer cell lines in nude mouse models. In vitro, A1-R infects tumor cells and can cause rapid nuclear fragmentation and apoptosis. A1-R was found to be effective against metastatic human prostate, breast, and pancreatic cancer cell lines as well as osteosarcoma, fibrosarcoma and glioma cell lines in clinically-relevant mouse models. Treated mice were often cured completely and survived as long as non- tumor-bearing mice. The approach described here, where bacterial monotherapy effectively treats primary and metastatic tumors, is a significant improvement over previous bacterial tumor-therapy strategies that require combination with toxic chemotherapy. The present application will develop bacterial therapy of cancer in immunocompetent mouse models as a bridge to clinical trials. Exploitation of the tumor-killing capability of Salmonella has great potential for a new paradigm of cancer therapy.