Alterations in DNA Damage following Major Surgery and Hyperthermic Intraperitoneal Chemotherapy

摘要/总结 近10%的转移性结直肠癌（mCRC）患者的疾病进展涉及 转移癌扩散到腹膜腔。这些患者通常有最坏的结果 mCRC患者。最近的一项III期多中心临床试验表明，单药免疫检查点 抑制剂（ICI）比标准细胞毒性化疗方案具有更高的疗效和更好的安全性， mCRC患者。重要的是，接受ICI治疗的适应症取决于高血压的测量。 肿瘤突变负荷（TMB）、新抗原负荷和微卫星不稳定性（MSI）状态。这些直接和 基因组不稳定性的间接测量可以预测对ICI的临床反应，然而，只有5%的患者 目前有资格接受这些治疗。 伴有腹膜扩散的mCRC患者可能会接受大细胞减灭术（CRS）， 切除所有病变部位。CRS联合腹腔热化疗 （HIPEC）与丝裂霉素C在43°C下的组合物以根除微观疾病。我们假设大手术 来自CRS的炎症以及HIPEC的热和化疗共同增加了基因组不稳定性。 已知外科炎症激活热休克蛋白（Hsps），其可使其调节控制不稳定 过度错配修复（MMR）蛋白导致DNA修复缺陷。这种情况与DNA结合 丝裂霉素c和热的破坏作用可能导致高TMB，增加新抗原，并改变MSI， 隐匿性显微镜下mCRC细胞。我们的总体假设是，接受CRS/HIPEC的患者将 有资格接受并将受益于ICI治疗。 我们建议在CRS/HIPEC前后从mCRC患者中采集血液样本和手术组织。 将评估这些标本的TMB和新抗原（Aim 1）以及MMR/MSI（Aim 2）的变化。从 手术组织，我们还将创建成对的患者源性类器官（PDO），我们将从中研究 Hsps、MMR蛋白和MSI。我们之前使用CRS/HIPEC患者PDO的研究支持其用于 评估CRS/HIPEC前后对ICI治疗的敏感性。我们提出以下具体目标： 具体目标1。测量由于热和DNA损伤而导致的TMB和新抗原的变化 丝裂霉素C对接受CRS/HIPEC的mCRC患者的影响。 具体目标2。为了确定手术炎症是否与热和DNA损伤效应相结合， 来自CRS/HIPEC的丝裂霉素C破坏MMR蛋白的HSP稳定以增加MSI。

ABSTRACT/SUMMARY Nearly 10% of patients with metastatic colorectal cancer (mCRC) have progression of disease involving the spread of metastatic cancer to the peritoneal cavity. These patients generally have the worst outcomes for all patients with mCRC. A recent phase III multicenter clinical trial has shown that single-agent immune checkpoint inhibitor (ICI) has greater efficacy and better safety profile than standard cytotoxic chemotherapy regimens for patients with mCRC. Importantly, indications to receive ICI therapy are dependent on the measurement of high tumor mutation burden (TMB), neoantigen burden, and microsatellite instability (MSI) status. These direct and indirect measures of genomic instability predict clinical response to ICIs, however, only 5% of patients are currently eligible to receive these therapies. Patients with mCRC with peritoneal spread of disease may undergo major cytoreductive surgery (CRS), during which all gross sites of disease are resected. CRS is combined with heated intraperitoneal chemotherapy (HIPEC) with mitomycin C at 43°C to eradicate microscopic disease. We hypothesize that major surgical inflammation from CRS and the heat and chemotherapy of HIPEC altogether increase genomic instability. Surgical inflammation is known to activate heat shock proteins (Hsps) which may destabilize its regulatory control over mismatch repair (MMR) proteins leading to deficient DNA repair. This condition combined with the DNA damaging effects of mitomycin c and heat may lead to high TMB, increased neoantigens, and altered MSI in occult microscopic mCRC cells. Our overarching hypothesis is that patients undergoing CRS/HIPEC will be eligible to receive and will benefit from ICI therapy. We propose to obtain blood samples and surgical tissues before and after CRS/HIPEC from patients with mCRC. These specimens will be assessed for changes in TMB and neoantigens (Aim 1) and MMR/MSI (Aim 2). From the surgical tissues, we will also create paired patient-derived organoids (PDOs) from which we will investigate Hsps, MMR proteins, and MSI. Our prior studies using PDOs from CRS/HIPEC patients support their use to assess sensitivities to ICI therapies before and after CRS/HIPEC. We propose the following specific aims: Specific Aim 1. To measure alterations in TMB and neoantigens as a result of the heat and DNA damaging effects of mitomycin C in mCRC patients undergoing CRS/HIPEC. Specific Aim 2. To determine whether surgical inflammation combined with heat and DNA damaging effects of mitomycin C from CRS/HIPEC disrupt Hsp-stabilization of MMR proteins to increase MSI.