PIK3CA signaling and pancreatic cancer

该方案的目的是探索如何靶向PIK3CA信号转导治疗胰管疾病。 腺癌(PDAC)。这种致命的癌症对目前的治疗方案高度耐药，包括 使用检查点抑制剂的免疫疗法。超过90%的PDAC在KRAS中存在癌基因突变，并且 PIK3CA是KRAS的直接效应因子。我们小组首次报道了胰腺中PIK3CA的基因消融 完全保护小鼠免受致癌的KRAS诱导的肿瘤形成，随后报道 PIK3CA通过保护胰腺肿瘤免受免疫系统的攻击，在维持胰腺肿瘤的过程中发挥了关键作用。 免疫活性KrasG12D、Trp53R172H、Pdx1-Cre(KPC)胰腺肿瘤细胞的原位移植 小鼠100%致死，而植入PIK3CA-/-KPC(PIK3CA-KO)KPC细胞的小鼠表现出 肿瘤消退，动物存活率100%。一种全基因组的基因缺失屏幕，以搜索 可以逆转免疫系统识别的PCCB对PIK3CA-KO细胞的消除，从而催化 丙酰辅酶A的羧化反应生成甲基丙二酰辅酶A。PCCB阴性的PIK3CA-KO KPC细胞 当移植到小鼠体内时，这些肿瘤不会被宿主免疫系统清除。二 假设将被检验：1)PIK3CA的致癌KRAS激活调节PCCB调节的代谢 有利于胰腺癌从免疫消除中逃脱的环境；以及2)Alpelisib抑制 PIK3CA增强抗PD1+抗PCSK9治疗胰腺肿瘤的活性。目标1 研究PIK3CA的KRAS激活调节PCCB调节的代谢的机制 有利于胰腺癌免疫逃逸的环境，包括上调免疫检查点 和T细胞衰竭。将肿瘤浸润性T细胞分离出来，并用单细胞RNA和T细胞进行分析 受体(TCR)V(D)J测序、流式细胞术和IHC。采用T细胞转移实验将是 以确定先前暴露于PCCB阴性的PIK3CA-KO肿瘤的T细胞是否会消除PIK3CA-KO- 将KO瘤移植到SCID小鼠体内。PCCB缺失的PIK3CA-KO与PIK3CA-KO的细胞代谢和免疫学特性 将测量PIK3CA-KO和亲本KPC细胞系，以更好地了解代谢变化 由PIK3CA和PCCB控制，以及这些变化如何导致免疫抑制。目标2是一个 一项测试PIK3CA抑制剂alpelisib与中和联合治疗效果的治疗研究 抗PD-1和PCSK9抗体原位植入KPC治疗胰腺癌 老鼠模型。肿瘤浸润性T细胞也将被分离并通过单细胞测序进行分析。在……里面 综上所述，本提案将研究PIK3CA信号如何调节代谢和免疫学 胰腺癌的侧写。Alpelisib、抗PD1抗体和抗PCSK9抗体都是FDA批准的用于 临床应用。成功完成我们的研究可能会导致这些批准的药物进行临床试验 胰腺癌的治疗。

The goal of this proposal is to explore how to target PIK3CA signaling for treatment of pancreatic ductal adenocarcinoma (PDAC). This deadly cancer is highly resistant to current treatment regimens, including immunotherapy with checkpoint inhibitors. More than 90% of PDAC have oncogenic mutations in KRAS, and PIK3CA is a direct effector of KRAS. Our group first reported that genetic ablation of PIK3CA in the pancreas completely protected mice against oncogenic KRAS-induced tumor formation, and subsequently reported that PIK3CA plays a critical role in sustaining pancreatic tumors by shielding them from the immune system. Orthotopic implantation of KrasG12D;Trp53R172H;Pdx1-Cre (KPC) pancreatic tumor cells in immunocompetent mice caused 100% lethality, whereas mice implanted with Pik3ca-/- KPC (PIK3CA-KO) KPC cells exhibited tumor regression with 100% animal survival. A genome-wide gene deletion screen to search for molecules that can reverse the elimination of PIK3CA-KO cells by the immune system identified PCCB, which catalyzes the carboxylation of propionyl-CoA to produce methylmalonyl-CoA. PCCB-null PIK3CA-KO KPC cells were generated, and when implanted in mice, these tumors were not cleared by the host immune system. Two hypotheses will be tested: 1) Oncogenic KRAS activation of PIK3CA modulates a PCCB-regulated metabolic environment that favors evasion of pancreatic cancer from immune elimination; and 2) Alpelisib inhibition of PIK3CA enhances the activity of anti-PD1 plus anti-PCSK9 therapy against pancreatic tumors. Aim 1 investigates mechanisms by which KRAS activation of PIK3CA modulates a PCCB-regulated metabolic environment that favors immune evasion of pancreatic cancer, including upregulation of immune checkpoints and T cell exhaustion. Tumor infiltrating T cells will be isolated and analyzed by single-cell RNA and T cell receptor (TCR) V(D)J sequencing, flow cytometry and IHC. Adoptive T cell transfer experiments will be performed to determine if T cells previously exposed to PCCB-null PIK3CA-KO tumors will eliminate PIK3CA- KO tumors implanted in SCID mice. Cell metabolism and immunological profile of PCCB-null PIK3CA-KO vs. PIK3CA-KO and parental KPC cell lines will be measured to better understand the metabolic alterations controlled by PIK3CA and PCCB and how these changes may lead to immune suppression. Aim 2 is a therapeutic study that tests the efficacy of alpelisib, a PIK3CA inhibitor, in combination with neutralizing antibodies against PD-1 and PCSK9 for treatment of pancreatic cancer using the orthotopically implanted KPC mouse model. Tumor infiltrating T cells will also be isolated and analyzed by single-cell sequencing. In summary, this proposal will investigate how PIK3CA signaling regulates the metabolic and immunological profile of pancreatic cancer. Alpelisib, anti-PD1 antibodies and anti-PCSK9 antibodies are all FDA-approved for clinical use. Successful completion of our studies may lead to clinical trials with these approved drugs for treatment of pancreatic cancer.