A stem cell strategy to induce tumor stasis and inhibit metastasis of breast canc

描述（由申请人提供）：乳腺癌细胞的恶性表型可以通过胚胎环境逆转为正常细胞表型，这突出了一种可能的新型细胞转化策略来治疗恶性乳腺癌，而不是杀死癌细胞。诱导多能干细胞（iPSC）技术可以将恶性癌细胞重编程为胚胎干细胞（ESC）样细胞，提供活胚胎环境。然而，目前iPSC技术的低转化率限制了其在癌症研究和治疗中的广泛应用。我们开发了一种蛋白质诱导的PSC （piPSC）技术，该技术使用Sox2/Oct4/Nanog （SON）蛋白将异质恶性乳腺癌细胞（malBCCs）重编程为piPSC，转化率为90¿4%。将4T1-piPSCs植入小鼠乳腺后，可使肿瘤停滞、转移抑制并向正常乳腺细胞分化。4T1细胞与4T1- pipscs共培养表明存在旁观者效应，使少量4T1- pipscs能够逆转周围大量4T1细胞的恶性表型。在4T1荷瘤小鼠瘤内直接注射SON蛋白可抑制肿瘤停滞和转移，提示原位细胞转化癌症治疗。通过尾静脉注射q - son蛋白，将这些蛋白靶向进入乳腺癌肿瘤细胞核。我们的中心假设是：“注射SON蛋白将malbcc原位转化为piPSCs，通过piPSCs的旁观者效应将周围malbcc的恶性表型逆转为正常细胞”。我们将首先优化从乳腺上皮细胞和malbcc生成piPSC。malbcc将与pipsc共培养，以研究是否可以在体外降低共培养的malbcc的致癌特性（目的1）。为了在体内研究旁观者效应，我们将采用不同的方法

DESCRIPTION (provided by applicant): Malignant phenotypes of breast cancer cells can be reversed into normal cell phenotypes by embryonic environments, highlighting a possible novel cell-converting strategy to treat malignant breast cancers instead of killing cancerous cells. The induced Pluripotent Stem Cell (iPSC) technique can reprogram malignant cancer cells into Embryonic Stem Cell (ESC)-like cells, providing living embryonic environments. However, the low conversion of the current iPSC technique limits its broad applications in cancer research and treatment. We developed a protein-induced PSC (piPSC) technique that reprogrammed heterogeneous malignant Breast Cancer Cells (malBCCs) into piPSCs using the Sox2/Oct4/Nanog (SON) proteins with 90¿4% conversion. Implantations of the 4T1-piPSCs into mouse mammary glands resulted in tumor stasis, metastasis inhibition and differentiation into normal mammary cells. Co-cultures of 4T1 cells with 4T1-piPSCs suggest a bystander effect that enables a small number of 4T1-piPSCs to reverse malignant phenotype of large numbers of surrounding 4T1 cells. Direct intra-tumor injections of the "SON" proteins in the 4T1 tumor bearing mice resulted in tumor stasis and metastasis inhibition, suggesting an in situ cell-converting cancer therapy. Tail vein injections of QQ-SON proteins targeted these proteins into the nuclei of tumor cells of breast cancer. Our central hypothesis is: "Injections of the "SON" proteins convert malBCCs into piPSCs in situ that reverse malignant phenotype of the surrounding malBCCs into normal cells via a bystander effect of piPSCs". We will first optimize piPSC generation from mammary epithelial cells and malBCCs. Co-cultures of malBCCs with piPSCs will be performed to study if oncogenic properties of the co-cultured malBCCs can be reduced in vitro (Aim 1). To investigate the bystander effect in vivo, we will administer different doses of (small numbers) piPSCs into the tumor (large numbers) of the tumor-bearing mice at different time points to study if these piPSCs can induce tumor stasis and inhibit metastasis in vivo (Aim 2). To mimic the clinical setting of breast cancer treatment, we will directly inject the "SON" proteins either via tail vein or via intra-tumor into the breast cancer-bearing mice at different time points to investigate if the in situ cell conversion can induce tumor stasis and inhibit metastasis, therefore delaying breast cancer recurrence and prolonging survival (Aim 3). Different from the current molecular-based cell-killing therapies, we will generate tissue-specific piPSCs in situ as living embryonic environments to reverse malignant phenotype of breast cancer cells into normal cells. This will be achieved by injections of the SON proteins via tail vein and via intra-tumor into breast cancer metastatic mouse models. Although this proposal focuses on a proof-of-principle verification, a protein-induced in situ cell-conversion strategy wil be easily translatable to human clinical applications. The success of this proposal may set a stage for future human clinical trials of this proposed cell converting breast cancer therapy by significantly delaying cancer recurrence, prolonging survival and improving outcomes of breast cancer patients.