A novel hotspot and rare somatic mutation p.A138V, at TP53 is associated with poor survival of pancreatic ductal and periampullary adenocarcinoma patients
一个新的热点和罕见的体细胞突变 p.A138V，at TP53 与胰腺导管和壶腹周围腺癌患者的生存率差相关
- 作者列表："Saha, Gourab","Singh, Richa","Mandal, Argha","Das, Subrata","Chattopadhyay, Esita","Panja, Prasun","Roy, Paromita","DeSarkar, Navonil","Gulati, Sumit","Ghatak, Supriyo","Ghosh, Shibajyoti","Banerjee, Sudeep","Roy, Bidyut","Ghosh, Saurabh","Chaudhuri, Dipankar","Arora, Neeraj","Biswas, Nidhan K.","Sikdar, Nilabja
Background Pancreatic Ductal Adenocarcinoma (PDAC) is a cancer of the exocrine pancreas and 5-year survival rates remain constant at 7%. Along with PDAC, Periampullary Adenocarcinoma (PAC) accounts for 0.5–2% of all gastrointestinal malignancies. Genomic observations were well concluded for PDAC and PACs in western countries but no reports are available from India till now. Methods Targeted Next Generation Sequencing were performed in 8 (5 PDAC and 3 PAC) tumour normal pairs, using a panel of 412 cancer related genes. Primary findings were replicated in 85 tumour samples (31 PDAC and 54 PAC) using the Sanger sequencing. Mutations were also validated by ASPCR, RFLP, and Ion Torrent sequencing. IHC along with molecular dynamics and docking studies were performed for the p.A138V mutant of TP53 . Key polymorphisms at TP53 and its associated genes were genotyped by PCR-RFLP method and association with somatic mutations were evaluated. All survival analysis was done using the Kaplan-Meier survival method which revealed that the survival rates varied significantly depending on the somatic mutations the patients harboured. Results Among the total 114 detected somatic mutations, TP53 was the most frequently mutated (41%) gene, followed by KRAS , SMAD4 , CTNNB1 , and ERBB3. We identified a novel hotspot TP53 mutation ( p.A138V , in 17% of all patients). Low frequency of KRAS mutation (33%) was detected in these samples compared to patients from Western counties. Molecular Dynamics (MD) simulation and DNA-protein docking analysis predicted p.A138V to have oncogenic characteristics. Patients with p.A138V mutation showed poorer overall survival ( p = 0.01 ). So, our finding highlights elevated prevalence of the p53 p.A138V somatic mutation in PDAC and pancreatobiliary PAC patients. Conclusion Detection of p.A138V somatic variant in TP53 might serve as a prognostic marker to classify patients. It might also have a role in determining treatment regimes. In addition, low frequency of KRAS hotspot mutation mostly in Indian PDAC patient cohort indicates presence of other early drivers in malignant transformation.
背景胰腺导管腺癌 (PDAC) 是一种胰腺外分泌癌，5 年生存率保持在 7% 不变。与 PDAC 一样，壶腹周围腺癌 (PAC) 占所有胃肠道恶性肿瘤的 0.5-2%。西方国家 PDAC 和 PACs 的基因组观察结论良好，但印度至今没有报道。方法使用一组 412 个癌症相关基因，在 8 个 (5 个 PDAC 和 3 个 PAC) 肿瘤正常对中进行靶向下一代测序。使用 Sanger 测序在 85 个肿瘤样本 (31 个 PDAC 和 54 个 PAC) 中复制了主要结果。突变也通过 ASPCR 、 RFLP 和 Ion Torrent 测序进行了验证。对 TP53 的 p.A138V 突变体进行了 IHC 以及分子动力学和对接研究。通过 PCR-RFLP 方法对 TP53 及其相关基因的关键多态性进行基因分型，并评价与体细胞突变的相关性。使用 Kaplan-Meier 生存方法进行所有生存分析，发现生存率因患者携带的体细胞突变而显著变化。结果在总共 114 个检测到的体细胞突变中，TP53 是最常突变的 (41%) 基因，其次是 KRAS 、 SMAD4 、 CTNNB1 和 erbb3。我们发现了一个新的热点 TP53 突变 (p.A138V，在 17% 的所有患者中)。与来自西部县的患者相比，在这些样本中检测到低频率的 KRAS 突变 (33%)。分子动力学 (MD) 模拟和 DNA-蛋白对接分析预测 p.A138V 具有致癌特征。P.A138V 突变的患者总生存期较差 (p = 0.01)。因此，我们的发现强调了 p53 p.A138V 体细胞突变在 PDAC 和胰胆管 PAC 患者中的患病率升高。结论检测 TP53 中 p.A138V 体细胞变异可作为判断患者预后的指标。它也可能在确定治疗方案中发挥作用。此外，KRAS 热点突变频率低，主要发生在印度 PDAC 患者队列中，表明恶性转化中存在其他早期驱动因素。
METHODS::Pancreatic ductal adenocarcinoma (PDAC) is a disease of aging. The TP53 gene product regulates cell growth, aging, and cancer. To determine the important targets of TP53 in PDAC, we examined the expression of 440 proteins on a reverse phase protein array (RPPA) in PDAC-derived MIA-PaCa-2 cells which either had WT-TP53 or lacked WT-TP53. MIA-PaCa-2 cells have a TP53 mutation as well as mutant KRAS and represent a good in vitro model to study PDAC. RPPA analysis demonstrated expression of tumor promoting proteins in cells that lacked WT-TP53; and this feature could be reversed significantly when the cells were transfected with vector encoding WT-TP53 or treated with berberine or a modified berberine (BBR). Expression of miR-34a-associated signaling was elevated in cells expressing WT-TP53 compared to cells expressing mTP53. Results from in vivo studies using human PDAC specimens confirmed the in vitro results as the expression of miR-34a and associated signaling was significantly decreased in PDAC specimens compared to non-cancerous tissues. This study determined SERPINE1 as a miR-34a target with relevance to the biology of PDAC. Thus, we have identified a key target (SERPINE1) of the TP53/miR-34a axis that may serve as a potential biomarker for early detection of pancreatic cancer.
METHODS::Background: SLC6A14 (ATB0,+), a Na+/Cl-coupled transporter for neutral/cationic amino acids, is overexpressed in many cancers; It has been investigated as a target for improved liposomal drug delivery to treat liver cancer.Research design and methods: Here we explored the mechanism of ATB0,+-mediated entry of such liposomes. As ATB0,+ is highly-expressed in pancreatic cancer, we also examined the therapeutic utility of ATB0,+-targeted liposomal drug delivery to treat this cancer.Results: The uptake of lysine-conjugated liposomes (LYS-LPs) was greater in ATB0,+-positive MCF7 cells. The uptake process consisted of two steps: binding and internalization. The binding of LYS-LPs to MCF7 cells was higher than that of bare liposomes, and the process was dependent on Na+ and Cl-, and inhibitable by ATB0,+ substrates or blocker. In contrast, the internalization step was independent of lysine. The cellular entry of LYS-LPs facilitated by ATB0,+ occurred via endocytosis with transient endosomal degradation of ATB0,+ protein with subsequent recovery. Moreover, LYS-LPs also enhanced the uptake and cytotoxicity of gemcitabine in these cells in an ATB0,+-dependent manner.Conclusions: We conclude that ATB0,+ could be exploited for targeted drug delivery in the form of lysine-conjugated liposomes and that the approach represents a novel strategy for enhanced pancreatic cancer therapy.
METHODS:PURPOSE:Pre-operative prediction of histological response to neoadjuvant therapy aids decisions regarding surgical management of borderline resectable pancreatic cancer (BRPC). We elucidate correlation between pre-/post-treatment whole-tumor apparent diffusion coefficient (ADC) value and rate of tumor cell destruction. We newly verify whether post-treatment ADC value at the site of vascular contact predicts R0 resectability of BRPC. METHODS:We prospectively reviewed 28 patients with BRPC who underwent diffusion-weighted magnetic resonance imaging before neoadjuvant chemotherapy and surgery. Correlation between the percentage of tumor cell destruction and various parameters was analyzed. Strong parameters were assessed for their ability to predict therapeutic histological response and R0 resectability. RESULTS:Pre-/post-treatment whole-tumor ADC value correlated with tumor cell destruction rate by all parameters (R = 0.630/0.714, P 50% was determined at 1.40 × 10-3 mm2/s. It predicts histological response with 100% sensitivity, 81% specificity, and 89% accuracy. It predicts R0 with 88% sensitivity, 70% specificity, and 75% accuracy. CONCLUSIONS:Post-treatment whole-tumor ADC value may be a predictor of R0 resectability in patients with BRPC. Tumor cell destruction rate is indicated by the difference between pre-/post-treatment ADC values. This difference is strongly affected by the pre-treatment ADC value. The cutoff value of ADC at the site of vascular contact could not discriminate R0 resectability.