Targeted tumoricidal bacteria

描述（由申请人提供）：我们已经开发了一种有效的细菌癌症治疗策略，其通过使用我们已经产生的鼠伤寒沙门氏菌营养缺陷型来靶向活的肿瘤组织，所述缺陷型在肿瘤的活的以及坏死的区域中生长。然而，营养缺陷型严重限制了这些细菌在正常组织中的生长，使其能够用于癌症治疗。色葡萄本实验室研制了一株leu-arg营养缺陷型、抗肿瘤毒力强的鼠伤寒A1-R突变株。在体外，A1-R感染肿瘤细胞并导致核破坏。A1-R最初用于治疗原位植入裸鼠体内的转移性人前列腺和乳腺肿瘤。40%的治疗小鼠完全治愈，存活时间与非荷瘤小鼠相同。A1-R对裸鼠原发性骨肉瘤和肺转移瘤有很好的治疗作用，尤其是抗转移作用。A1-R还分别靶向人胰腺癌和纤维肉瘤的腋窝淋巴结和腘淋巴结转移，以及裸鼠中纤维肉瘤的肺转移。细菌通过淋巴通道递送以靶向淋巴结转移，并通过尾静脉全身递送以靶向肺转移。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瘤内给予具有原位移植的人胰腺肿瘤的裸鼠。原发性胰腺癌在没有额外化疗或任何其他治疗的情况下消退。A1-R对裸鼠脾内给药也有效对抗胰腺癌肝转移。A1-R还显示对原位小鼠模型中的脊髓胶质瘤有效。这里描述的方法，其中细菌单一疗法有效地治疗原发性和转移性肿瘤，是对以前的细菌肿瘤治疗策略的显着改进，需要与毒性化疗相结合。本申请将开发用S.鼠伤寒A1-R在免疫功能正常的小鼠作为一个桥梁，以临床。本申请的具体目的是（1）确定S的最大耐受剂量（MTD）。鼠伤寒沙门氏菌A1-R在荷瘤C57免疫活性小鼠。(2)确定S.鼠伤寒沙门氏菌A1-R在荷瘤免疫活性小鼠。沙门氏菌的肿瘤杀伤能力的开发具有巨大的潜力，为癌症治疗的新范式。 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体的细菌癌症治疗策略。这些细菌杀死癌细胞，但不会在正常组织中生长。我们的S。鼠伤寒A1-R突变体在裸鼠模型中对许多癌细胞系具有抗肿瘤毒力。在体外，A1-R感染肿瘤细胞，可引起快速的核碎裂和凋亡。在临床相关小鼠模型中，发现A1-R对转移性人前列腺癌、乳腺癌和胰腺癌细胞系以及骨肉瘤、纤维肉瘤和神经胶质瘤细胞系有效。经治疗的小鼠通常完全治愈，并且存活时间与非荷瘤小鼠一样长。这里描述的方法，其中细菌单一疗法有效地治疗原发性和转移性肿瘤，是对以前的细菌肿瘤治疗策略的显着改进，需要与毒性化疗相结合。本申请将在免疫活性小鼠模型中开发癌症的细菌疗法作为临床试验的桥梁。沙门氏菌的肿瘤杀伤能力的开发具有巨大的潜力，为癌症治疗的新范式。

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.