Targeting MARK2-HDAC signaling to overcome paclitaxel resistance in pancreatic cancer

摘要文本 许多抗微管蛋白药物，如紫杉醇，已被广泛用于几种类型的治疗 癌症，包括乳腺癌、卵巢癌、肺癌和胰腺癌。尽管它们在癌症治疗中被广泛使用， 然而，患者的反应是高度可变的，耐药性仍然是一个主要的临床问题。因此，它是 必须确定预后标记物，以预测患者的反应并提高药物敏感性。 通过生物化学和基于细胞的全基因组筛选，我们鉴定了Mark2(微管亲和力- 调节激酶2)作为紫杉醇对胰腺导管化疗敏感性的关键调节因子 腺癌)细胞。我们发现Mark2在抗微管蛋白化疗药物作用下被磷酸化。 我们进一步鉴定了相应的激酶并绘制了磷酸化位点图。Mark2确定紫杉醇 正常情况下对PDAC细胞的细胞毒作用而不影响生长。从机制上讲，我们的发现还 提示Mark2通过调节IIa类HDAC(组蛋白脱乙酰酶)来控制紫杉醇的化疗敏感性。 在紫杉醇处理后，Mark2直接使HDAC4磷酸化。Mark2-磷酸化HDAC4呈阳性 特异性地调节YAP(YES相关蛋白)活性并控制YAP靶基因的表达 紫杉醇诱导。体外和体外抑制HDAC使PDAC细胞对紫杉醇的敏感性 具有免疫能力的动物。我们的假设是Mark2-HDACs轴作为一个治疗靶点发挥作用 用于克服PDAC患者的紫杉醇耐药。我们将通过三个具体目标来检验我们的中心假设。 目的1：确定Mark2在抗微管蛋白化疗药物反应中的作用和调节；目的2： 阐明MARK2对紫杉醇化疗药物的下游效应和机制；目的 3：靶向HDAC和丝氨酸代谢以克服PDAC对紫杉醇的耐药性。新产品的识别 由抗微管蛋白药物触发的调节器和/或信号通路将有助于阐明这些机制 潜在的化疗耐药性。我们的研究表明，将HDAC抑制剂与抗微管蛋白药物(例如 紫杉醇)在治疗耐药和/或复发的PDAC患者方面将具有更高的疗效。

Abstract Text Many antitubulin agents, such as paclitaxel (Taxol), have been used extensively for treatment of several types of cancer, including breast, ovarian, lung, and pancreatic cancers. Despite their wide use in cancer treatment, however, patient response is highly variable and drug resistance remains a major clinical issue. It is therefore essential to identify prognostic markers to predict the patient response and to enhance drug sensitivity. Through biochemical and cell-based kinome-wide screens, we identified MARK2 (microtubule affinity- regulating kinase 2) as a critical regulator for Taxol chemosensitivity in PDAC (pancreatic ductal adenocarcinoma) cells. We show that MARK2 is phosphorylated in response to antitubulin chemotherapeutics. We further identified the corresponding kinase and mapped phosphorylation sites. MARK2 determines Taxol cytotoxicity in PDAC cells without affecting growth under normal conditions. Mechanistically, our findings also suggest that MARK2 controls Taxol chemosensitivity by regulating class IIa HDACs (histone deacetylase). MARK2 directly phosphorylates HDAC4 upon Taxol treatment. MARK2-phosphorylated HDAC4 positively regulates YAP (yes-associated protein) activity and controls expression of YAP target genes specifically induced by Taxol. Inhibition of HDACs sensitizes PDAC cells to Taxol treatment in vitro and in immunocompetent animals. Our hypothesis is that the MARK2-HDACs axis functions as a therapeutic target for overcoming Taxol resistance in PDAC patients. We will test our central hypothesis by three specific aims. Aim 1: Determine the role and regulation of MARK2 in response to antitubulin chemotherapeutics; Aim 2: Elucidate the downstream effectors and mechanisms of MARK2 in response to Taxol chemotherapeutics; Aim 3: Targeting HDACs and serine metabolism to overcome Taxol resistance in PDAC. The identification of new regulators and/or signaling pathways triggered by antitubulin drugs will shed light on the mechanisms underlying chemoresistance. Our study suggests that combining HDAC inhibitors with antitubulin agents (e.g. Taxol) will have enhanced efficacy in treatment of drug-resistant and/or recurrent PDAC patients.