Activating Cell Death Pathways in Breast Cancer Cells

癌细胞通过多种遗传和表观遗传机制避免凋亡。TNF 家族死亡受体（例如，TNFR、Fas、DR 3、TRAIL受体1和TRAIL受体2）诱导 在细胞凋亡中通过募集和激活半胱天冬酶， 配体（例如，TNF、Fas配体和TRAIL）。我们正在研究表达和功能 TRAIL死亡受体（TNFR家族的成员）及其配体（例如，TRAIL和 激动性抗体），以选择性地触发乳腺癌细胞中的细胞凋亡。 癌细胞在我们的早期工作中，我们发现大多数乳腺癌细胞系对 TRAIL诱导细胞凋亡。我们已经证明了一部分乳腺癌 细胞，那些具有三阴性/基底样特征的细胞对TRAIL诱导的细胞非常敏感。 凋亡，而其他乳腺癌亚型对TRAIL诱导的凋亡相对耐受。 凋亡这种乳腺癌的子集特别具有侵袭性，最需要 靶向治疗。此外，我们发现，TRAIL受体2，而不是TRAIL受体1， 在敏感的乳腺癌细胞中TRAIL诱导凋亡所需的。后一项发现 将有助于选择TRAIL激动剂用于乳腺癌的最终临床试验 患者此外，我们发现对TRAIL诱导的细胞凋亡的抗性可以是 通过将细胞与化疗剂、靶向剂如 曲妥珠单抗和EGFR抑制剂。最近，我们已经证明，抑制或损失 G2/M检查点酪氨酸激酶Wee 1增强TRAIL介导的基底细胞样凋亡 乳腺癌细胞这些研究一起开始提供明确的临床前 单独或与其他药物联合应用于患者的研究原理 患有乳腺癌正在进行的工作是：1）利用功能基因组学来识别和表征 乳腺癌中调控TRAIL受体激动剂诱导的细胞凋亡的基因和蛋白 癌细胞2)表征乳腺癌细胞中的新型TRAIL受体激动剂，3） 评价对乳腺癌细胞免疫原性的影响。在一个衍生项目中， 表征ClpP激动剂的作用机制。后一种药物被描述为 通过TRAIL途径。然而，我们的数据表明它的工作独立于TRAIL 杀死乳腺癌和其他癌细胞的途径。我们正在进行的工作包括：1） 表征ClpP激动剂对乳腺癌细胞诱导的死亡机制; 2）在乳腺癌细胞中， 与NCATS合作，我们进行了筛选，以确定与ClpP协同作用的药物 乳腺癌细胞中的激动剂，并正在验证该筛选的结果， 将与ClpP激动剂一起使用的组合疗法。3)调查的影响 ClpP激动剂对乳腺癌肿瘤起始细胞的作用。

Cancer cells avoid apoptosis by a variety of genetic and epigenetic mechanisms. TNF family death receptors (e.g., TNFR, Fas, DR3, TRAIL Receptor 1, and TRAIL Receptor 2) induce apoptosis in cells by recruiting and activating caspases upon activation by their respective ligands (e.g., TNF, Fas Ligand, and TRAIL). We are investigating the expression and function of TRAIL death receptors (members of the TNFR family) and their ligands (e.g., TRAIL and agonistic antibodies) in breast cancer cells in order to selectively trigger apoptosis in the cancer cells. In our early work, we found that most breast cancer cell lines are resistant to the induction of apoptosis by TRAIL. We have demonstrated that a subset of breast cancer cells, those with triple-negative/basal-like features are very sensitive to TRAIL-induced apoptosis while other breast cancer subtypes are relatively resistant to TRAIL-induced apoptosis. This subset of breast cancers is particularly aggressive and most in need of targeted therapies. Further, we found that TRAIL Receptor 2, and not TRAIL Receptor 1, is required for TRAIL induced apoptosis in the sensitive breast cancer cells. This latter finding will help in the selection of TRAIL agonists for eventual clinical trials in breast cancer patients. In addition, we have found that resistance to TRAIL-induced apoptosis can be overcome by co-incubation of the cells with chemotherapeutic agents, targeted agents such as trastuzumab, and EGFR inhibitors. More recently, we have demonstrated that inhibition or loss of the G2/M checkpoint tyrosine kinase Wee1 enhances TRAIL-mediated apoptosis in basal-like breast cancer cells. Together these studies are beginning to provide clear preclinical rationales for studies of TRAIL ligands alone or in combination with other drugs in patients with breast cancer. Ongoing work is: 1) using functional genomics to identify and characterize the genes and proteins that regulate apoptosis induced by TRAIL receptor agonists in breast cancer cells. 2) characterizing novel TRAIL receptor agonists in breast cancer cells, 3) evaluating the effects on the immunogenecity of breast cancer cells. In a spin off projject we are characterizing the mechanism of action of ClpP agonists. The latter drug was described to work via the TRAIL pathway. However, our data suggest that it works independent of the TRAIL pathway to kill breast cancer and other cancer cells. Our ongoing work includes 1) characterizing the mchanism of death induced by ClpP agonists on breast cancer cells; 2) in collaboration with NCATS we conducted a screen to identify drugs that synergize with ClpP agonists in breast cancer cells and are validating hits from that screen to credential combination therapies that will be useful with ClpP agonists. 3) investigating the effects of ClpP agonists on breast cancer tumor initiating cells.