Dietary intervention of non-classical Wnt signaling

 描述（由申请人提供）：由于相关的治疗耐药性、疾病复发和死亡率，乳腺癌的侵袭性和转移性带来了巨大的挑战。癌细胞的行为取决于它们与周围组织的相互作用。骨桥蛋白（OPN）是乳腺基质的重要组成部分。OPN在70%以上的恶性乳腺肿瘤中过表达，其过表达提示预后不良。骨桥蛋白增强细胞的恶性性质，特别是通过促进其生长，侵袭和转移的能力。Wnt信号在乳腺癌中失调。我们发现Wnt稳态的错误调节导致EMT激活和恶性进展。我们还证明，DNA JB 6，一个HSP 40家族的分子伴侣，干扰Wnt/β-catenin信号传导，事实上，作为EMT的看门人，导致转移减少。在乳腺癌的侵袭性进展中，DNAJB 6蛋白表达受损。DNAJB 6表达的缺失是促进肿瘤细胞分泌OPN的关键因素之一。该提议的中心假设是OPN激活Wnt-配体非依赖性、非经典β-连环蛋白信号传导，导致乳腺癌的恶性进展。β-连环蛋白活性的这种非经典激活具有深远的意义， 在肿瘤进展、多药耐药性方面，重要的是在临床上测试的Wnt抑制剂方面。基于关于其抵消Wnt信号传导和恢复DNAJB 6表达的能力的令人信服的观察，我们建议测试膳食类黄酮，非瑟酮用于逆转或预防EMT和对药物治疗的抗性。非瑟酮大量存在于芒果、草莓等中，因此是一种负担得起的膳食补充剂。我们的目标是（i）表征β-catenin信号传导的非经典激活的机制和作用，以及（ii）确定非瑟酮是否作为有效的功能性食物来逆转EMT和预防转移。我们还将测试非瑟酮对提高乳腺癌细胞对细胞毒性化疗的敏感性的影响。结果将允许使用非瑟酮作为饮食干预来阻断肿瘤微环境中由于OPN引起的非经典β-连环蛋白信号传导。这项工作还将测试干预乳腺癌转移扩散的预防策略。影响：考虑到正在进行的临床试验对抑制Wnt信号传导的重视，拟议的工作将对正在进行的临床试验产生直接影响。这项研究有可能补充昂贵和衰弱的化疗方案。

 DESCRIPTION (provided by applicant): The invasive and metastatic nature of breast cancer poses a formidable challenge due to the associated therapeutic resistance, disease relapse and mortality. The behavior of cancer cells is dictated by their interaction with their surrounding tissue. Osteopontin (OPN) is a critical component of breast stroma. OPN is overexpressed in over 70% cases of malignant breast neoplasms and its overexpression is indicative of poor prognosis. OPN potentiates malignant properties of cells, specifically by promoting their ability to grow, invade, and metastasize. Wnt signaling is dysregulated in breast cancer. We showed that mis-regulation of Wnt homeostasis results in EMT activation and malignant progression. We also demonstrated that DNAJB6, a member of HSP40 family of chaperones, interferes with Wnt/β-catenin signaling and in fact, acts as a gatekeeper of EMT resulting in reduced metastasis. In invasive progression of breast cancer, DNAJB6 protein expression is compromised. Loss of DNAJB6 expression is one of the key factors that promote secretion of OPN by the tumor cells. The central hypothesis of this proposal is that OPN activates Wnt-ligand independent, non-classical β- catenin signaling, leading to malignant progression of breast cancer. This non-classical activation of β- catenin activity has profound implications with respect to tumor progression, multi-drug resistance and importantly to Wnt inhibitors being tested in the clinic. Based on compelling observations regarding its ability to counteract Wnt signaling, and restore DNAJB6 expression, we propose to test the dietary flavonoid, fisetin for reversing or preventing EMT and resistance to drug treatment. Fisetin is abundantly present in mangos, strawberries etc. and thus are an affordable means of dietary supplementation. Our objectives are (i) To characterize the mechanisms and effects of non-classical activation of β-catenin signaling and (ii) To determine if fisetin serves as an effective functional food to revere EMT and prevent metastasis. We will also test fisetin's impact on improving sensitivity of breast cancer cells to cytotoxic chemotherapy. The outcome will allow use of fisetin as a dietary intervention to block non-classical β-catenin signaling due to OPN in the tumor microenvironment. The work will also test prevention strategies to intervene in metastatic dissemination of breast cancer. Impact: Considering the emphasis of ongoing clinical trials on inhibition of Wnt signaling, the proposed work will have immediate impact on the course of ongoing clinical trials. This research has the potential to complement costly and debilitating chemotherapy regimens.