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129 result(s) for "Singhi, Aatur"
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Early detection of pancreatic cancer using DNA-based molecular approaches
Due to its poor prognosis and the late stage at which it is typically diagnosed, early detection of pancreatic cancer is a pressing clinical problem. Advances in genomic analysis of human pancreatic tissue and other biospecimens such as pancreatic cyst fluid, pancreatic juice and blood have opened the possibility of DNA-based molecular approaches for early detection of pancreatic cancer. In this Review, we discuss and focus on the pathological and molecular features of precancerous lesions of the pancreas, including pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm and mucinous cystic neoplasm, which are target lesions of early detection approaches. We also discuss the most prevalent genetic alterations in these precancerous lesions, including somatic mutations in the oncogenes KRAS and GNAS as well as tumour suppressor genes CDKN2A , TP53 and SMAD4 . We highlight the latest discoveries related to genetic heterogeneity and multifocal neoplasia in precancerous lesions. In addition, we review specific approaches, challenges and clinically available assays for early detection of pancreatic cancer using DNA-based molecular techniques. Although detection and risk stratification of precancerous pancreatic neoplasms are difficult problems, progress in this field highlights the promise of molecular approaches for improving survival of patients with this disease. Pancreatic cancer is typically diagnosed at a late stage and early detection is a priority. This Review focuses on precancerous lesions of the pancreas, describing their pathological and molecular features and highlighting different DNA-based molecular approaches for early detection and their clinical utility. Key points The target lesions for pancreatic cancer screening are high-grade precancerous lesions and early-stage invasive cancers. Precancerous lesions can be microscopic (pancreatic intraepithelial neoplasia (PanIN)) or macroscopic (intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm (MCN)), and these lesions are classified as low-grade or high-grade based on the morphological grade of dysplasia of their lining epithelium; although low-grade lesions share early oncogene mutations such as KRAS , mutations in other genes ( CDKN2A , TP53 and SMAD4 ) are limited to more advanced lesions. Studies have highlighted genetic heterogeneity in precancerous lesions and multifocal neoplasia in the pancreas, which should be considered when designing early detection approaches. The evolving understanding of the genetics of precancerous lesions has led to the development of clinically available assays for pancreatic cyst classification and detection of high-grade dysplasia and early-stage pancreatic cancers. Mutations in KRAS and/or GNAS are highly specific for mucinous cysts, such as IPMNs, while alterations in CDKN2A , TP53 and/or SMAD4 are almost exclusively seen in the setting of advanced lesions. The assessment of genetic alterations using a non-invasive method, such as from a patient’s blood specimen, holds promise not only for early detection of pancreatic cancer but also for the identification of precancerous lesions.
Preoperative next-generation sequencing of pancreatic cyst fluid is highly accurate in cyst classification and detection of advanced neoplasia
ObjectiveDNA-based testing of pancreatic cyst fluid (PCF) is a useful adjunct to the evaluation of pancreatic cysts (PCs). Mutations in KRAS/GNAS are highly specific for intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs), while TP53/PIK3CA/PTEN alterations are associated with advanced neoplasia. A prospective study was performed to evaluate preoperative PCF DNA testing.DesignOver 43-months, 626 PCF specimens from 595 patients were obtained by endoscopic ultrasound (EUS)-fine needle aspiration and assessed by targeted next-generation sequencing (NGS). Molecular results were correlated with EUS findings, ancillary studies and follow-up. A separate cohort of 159 PCF specimens was also evaluated for KRAS/GNAS mutations by Sanger sequencing.Results KRAS/GNAS mutations were identified in 308 (49%) PCs, while alterations in TP53/PIK3CA/PTEN were present in 35 (6%) cases. Based on 102 (17%) patients with surgical follow-up, KRAS/GNAS mutations were detected in 56 (100%) IPMNs and 3 (30%) MCNs, and associated with 89% sensitivity and 100% specificity for a mucinous PC. In comparison, KRAS/GNAS mutations by Sanger sequencing had a 65% sensitivity and 100% specificity. By NGS, the combination of KRAS/GNAS mutations and alterations in TP53/PIK3CA/PTEN had an 89% sensitivity and 100% specificity for advanced neoplasia. Ductal dilatation, a mural nodule and malignant cytopathology had lower sensitivities (42%, 32% and 32%, respectively) and specificities (74%, 94% and 98%, respectively).ConclusionsIn contrast to Sanger sequencing, preoperative NGS of PCF for KRAS/GNAS mutations is highly sensitive for IPMNs and specific for mucinous PCs. In addition, the combination of TP53/PIK3CA/PTEN alterations is a useful preoperative marker for advanced neoplasia.
Inhibition of endoplasmic-reticulum-stress-mediated autophagy enhances the effectiveness of chemotherapeutics on pancreatic cancer
Background Endoplasmic reticulum (ER) stress and its consequent unfolded protein response (UPR) are believed to be associated with progression, survival and chemoresistance of a variety of tumor cells through multiple cellular processes, including autophagy. Therefore, the ER stress-autophagy pathway presents a potential molecular target for therapeutic intervention. The objective of this study was to evaluate the therapeutic efficacy of ER stress and autophagy modulators in the context of pancreatic ductal adenocarcinoma (PDAC). Methods We first targeted IRE1α, an important regulator of the UPR, through STF-083010 treatment in PDAC cell lines in vitro. Chloroquine was then used to target autophagy and an optimal combination treatment was developed using chloroquine, sunitinib and gemcitabine. Apoptosis was analyzed using TUNEL assay, autophagy was estimated using lysotracker staining and electron microscopy, and UPR was analyzed using anti-GRP78 immunostaining and XBP1 splicing. Transplantation of PDAC derived KPCP1 and Panc02 cells in mouse pancreas were performed to study treatment efficacy in vivo. Results Suppression of the IRE1α by STF-083010 alone resulted in increased lysosomes and reduced viability of PDAC cells. Chloroquine treatment alone inhibited downstream autophagy but was insufficient in reducing PDAC cell growth. However, combining STF-083010 and chloroquine had additive anti-tumor efficacy when used with gemcitabine. Sunitinib alone caused abnormal maturation of the autolysosomes with increased intracellular multivesicular bodies and increased apoptosis evident in PDAC cells. Sunitinib showed a synergistic effect with chloroquine in reducing in vitro PDAC cell viability and significantly increased the efficacy of gemcitabine in human and murine PDAC cell lines. The anti-proliferative effect of gemcitabine was significantly increased when used in combination with sunitinib and/or chloroquine in both in vitro and in vivo PDAC models. The addition of sunitinib and/or chloroquine to gemcitabine, resulted in a significantly increased survival of the animals without noticeably increased toxicity. Sunitinib, gemcitabine and chloroquine treated mice showed a significant reduction of GRP78 expression, reduced cell proliferation and increased apoptosis in pancreas, compatible with a tumor response. Conclusions Sunitinib combined with chloroquine reduces tumor growth through suppression of autophagy and increased apoptosis. Co-administration of modulators of ER stress-mediated autophagy with chemotherapy presents a novel therapeutic approach in PDAC.
Myeloid FoxO1 depletion attenuates hepatic inflammation and prevents nonalcoholic steatohepatitis
Hepatic inflammation is culpable for the evolution of asymptomatic steatosis to nonalcoholic steatohepatitis (NASH). Hepatic inflammation results from abnormal macrophage activation. We found that FoxO1 links overnutrition to hepatic inflammation by regulating macrophage polarization and activation. FoxO1 was upregulated in hepatic macrophages, correlating with hepatic inflammation, steatosis and fibrosis in mice and patients with NASH. Myeloid cell-conditional FoxO1 knockout skewed macrophage polarization from pro-inflammatory M1 to anti-inflammatory M2 phenotypes, accompanied by the reduction of macrophage infiltration in liver. These effects mitigated overnutrition-induced hepatic inflammation and insulin resistance, contributing to improved hepatic metabolism and increased energy expenditure in myeloid cell FoxO1 knockout mice on HFD. When fed a NASH-inducing diet, myeloid cell FoxO1 knockout mice were protected from developing NASH, culminating in the reduction of hepatic inflammation, steatosis and fibrosis. Mechanistically, FoxO1 counteracts Stat6 to skew macrophage polarization from M2 toward M1 signatures to perpetuate hepatic inflammation in NASH. FoxO1 appears as a pivotal mediator of macrophage activation in response to overnutrition and a therapeutic target for ameliorating hepatic inflammation to stem the disease progression from benign steatosis to NASH.
The prognostic significance of BAP1, NF2, and CDKN2A in malignant peritoneal mesothelioma
Cytoreductive surgery and hyperthermic intraperitoneal chemoperfusion for patients with malignant peritoneal mesothelioma has resulted in improved disease control and increased survival. Despite these results, there are significant perioperative risks associated with this aggressive procedure that necessitate consideration of prognostic markers during patient selection. The molecular pathogenesis of peritoneal mesothelioma remains relatively unknown, but extrapolation of findings from their pleural counterpart would suggest frequent alterations in CDKN2A , NF2 , and BAP1 . Homozygous deletions in CDKN2A portend a worse overall survival in peritoneal mesothelioma. However, the prevalence and prognostic significance of NF2 and BAP1 abnormalities has not been studied. Dual-color fluorescence in situ hybridization using CDKN2A and NF2 locus-specific probes and BAP1 immunohistochemistry identified homozygous CDKN2A deletions ( n =25, 29%), hemizygous NF2 loss ( n =30, 35%), and/or loss of BAP1 protein expression ( n =49, 57%) in 68 of 86 (79%) peritoneal mesotheliomas. Homozygous CDKN2A deletions or hemizygous NF2 loss correlated with shorter progression-free survival ( P <0.02) and poor overall survival ( P <0.03). Moreover, the significance of these findings was cumulative. Patients harboring both homozygous CDKN2A deletions and hemizygous NF2 loss had a 2-year progression-free survival rate of 9% with a median of 6 months ( P <0.01) and overall survival rate of 18% with a median of 8 months ( P <0.01). By multivariate analysis, combined homozygous CDKN2A deletions and hemizygous NF2 loss was a negative prognostic factor for both progression-free survival and overall survival, independent of patient age, peritoneal cancer index, completeness of cytoreduction, and extent of invasion. In contrast, loss of BAP1 was not associated with clinical outcome. In summary, homozygous deletions in CDKN2A and hemizygous loss of NF2 as detected by fluorescence in situ hybridization would confer a poor clinical outcome and may guide future treatment decisions for patients with peritoneal mesothelioma.
CA19-9 Change During Neoadjuvant Therapy May Guide the Need for Additional Adjuvant Therapy Following Resected Pancreatic Cancer
BackgroundNeoadjuvant therapy (NAT) is increasingly utilized for pancreatic cancer, however the added benefit of adjuvant therapy (AT) in this setting is unknown. We hypothesized that the magnitude of CA19-9 response to NAT can guide the need for further AT in resected pancreatic cancer.MethodsCA19-9 secretors who received NAT for pancreatic cancer during 2008–2016 at a single institution were analyzed and CA19-9 response (difference between pre- and post-NAT values) was measured. Kaplan–Meier estimators and Cox proportional hazard ratio models were used to determine the optimal CA19-9 response at which AT ceases to confer any additional survival benefit after NAT.ResultsA total of 241 patients (mean age 65.4 years, 50% female) with complete CA19-9 data who underwent NAT followed by resection were analyzed. In a cohort of patients (n = 78) in whom CA19-9 normalized with a decrease > 50% after NAT (optimal responders), AT was not associated with additional survival benefit (40.6 vs. 39.0 months, p = 0.815). Conversely, in the cohort of patients (n = 163) in whom NAT was not associated with normalization and a decrease of ≤ 50% in CA19-9 (suboptimal responders), receipt of AT was associated with a survival benefit (34.5 vs. 19.1 months, p < 0.001) following NAT. A Cox proportional hazards model confirmed CA19-9 normalization and decrease > 50% during NAT to predict no additional survival benefit from AT.ConclusionsThe magnitude of CA19-9 response to NAT may predict the need for further AT in resected pancreatic cancer. Prospective studies are needed to elucidate the optimal interplay of NAT and AT in pancreatic cancer.
NKX3.1 Expression and Molecular Characterization of Secretory Myoepithelial Carcinoma (SMCA): Advancing the Case for a Salivary Mucous Acinar Phenotype
Background Secretory myoepithelial carcinomas (SMCA) are rare, mucinous, signet ring predominant tumors with primitive myoepithelial features. While many mucinous salivary gland tumors have now been molecularly characterized, key drivers in SMCA have yet to be elucidated. Recently, NKX3.1, a homeodomain transcription factor implicated in salivary mucous acinar development was also shown in a subset of salivary mucinous neoplasms, salivary intraductal papillary mucinous neoplasms (SG-IPMN). To date, NKX3.1 expression has not been characterized in other mucinous salivary lesions. Here, we report molecular and extended immunophenotypic findings in SMCA and NKX3.1 expression in the context of other head and neck lesions. Methods We retrieved 4 previously reported SMCA, performed additional immunohistochemical and targeted next-generation sequencing (NGS). We also investigated the use of NKX3.1 as a marker for SMCA in the context of its prevalence and extent (using H-score) in a mixed cohort of retrospectively and prospectively tested head and neck lesions ( n  = 223) and non-neoplastic tissues ( n  = 66). Results NKX3.1 positivity was confirmed in normal mucous acini as well as in mucous acinar class of lesions (5/6, mean H-score: 136.7), including mucinous adenocarcinomas (3/4), SG-IPMN (1/1), and microsecretory adenocarcinoma (MSA) (1/1). All SMCA were positive. Fluorescence in situ hybridization for SS18 rearrangements were negative in all successfully tested cases (0/3). NGS was successful in two cases (cases 3 and 4). Case 3 demonstrated a PTEN c.655C > T p.Q219* mutation and a SEC16A::NOTCH1 fusion while case 4 (clinically aggressive) showed a PTEN c.1026 + 1G > A p.K342 splice site variant, a TP53 c.524G > A p.R175H mutation and a higher tumor mutation burden (29 per Mb). PTEN immunohistochemical loss was confirmed in both cases and a subset of tumor cells showed strong (extreme) staining for P53 in Case 4. Conclusion Despite a partial myoepithelial phenotype, SMCA, along with mucinous adenocarcinomas/SG-IPMN and MSA, provisionally constitute a mucous acinar class of tumors based on morphology and NKX3.1 expression. Like salivary mucinous adenocarcinomas/SG-IPMN, SMCA also show alterations of the PTEN/PI3K/AKT pathway and may show progressive molecular alterations. We document the first extramammary tumor with a SEC16A::NOTCH1 fusion.
Reconstitution of human PDAC using primary cells reveals oncogenic transcriptomic features at tumor onset
Animal studies have demonstrated the ability of pancreatic acinar cells to transform into pancreatic ductal adenocarcinoma (PDAC). However, the tumorigenic potential of human pancreatic acinar cells remains under debate. To address this gap in knowledge, we expand sorted human acinar cells as 3D organoids and genetically modify them through introduction of common PDAC mutations. The acinar organoids undergo dramatic transcriptional alterations but maintain a recognizable DNA methylation signature. The transcriptomes of acinar organoids are similar to those of disease-specific cell populations. Oncogenic KRAS alone do not transform acinar organoids. However, acinar organoids can form PDAC in vivo after acquiring the four most common driver mutations of this disease. Similarly, sorted ductal cells carrying these genetic mutations can also form PDAC, thus experimentally proving that PDACs can originate from both human acinar and ductal cells. RNA-seq analysis reveal the transcriptional shift from normal acinar cells towards PDACs with enhanced proliferation, metabolic rewiring, down-regulation of MHC molecules, and alterations in the coagulation and complement cascade. By comparing PDAC-like cells with normal pancreas and PDAC samples, we identify a group of genes with elevated expression during early transformation which represent potential early diagnostic biomarkers. The cellular origin of human pancreatic ductal adenocarcinoma (PDAC) is still unclear. Here the authors used human primary acinar and ductal cells to successfully reconstitute PDAC tumorigenesis from both lineages and revealed transcriptional changes during early PDAC progression.
Enhanced Neutrophil Extracellular Trap Formation in Acute Pancreatitis Contributes to Disease Severity and Is Reduced by Chloroquine
Neutrophil extracellular traps (NETs) are generated when activated neutrophils, driven by PAD4, release their DNA, histones, HMGB1, and other intracellular granule components. NETs play a role in acute pancreatitis, worsening pancreatic inflammation, and promoting pancreatic duct obstruction. The autophagy inhibitor chloroquine (CQ) inhibits NET formation; therefore, we investigated the impact of CQ mediated NET inhibition in murine models of pancreatitis and human correlative studies. L-arginine and choline deficient ethionine supplemented (CDE) diet models of acute pancreatitis were studied in wild type and PAD4 mice, incapable of forming NETs. Isolated neutrophils were stimulated to induce NET formation and visualized with fluorescence microscopy. CQ treatment (0.5 mg/ml PO) was initiated after induction of pancreatitis. Biomarkers of NET formation, including cell-free DNA, citrullinated histone H3 (CitH3), and MPO-DNA conjugates were measured in murine serum and correlative human patient serum samples. We first confirmed the role of NETs in the pathophysiology of acute pancreatitis by demonstrating that PAD4 mice had decreased pancreatitis severity and improved survival compared to wild-type controls. Furthermore, patients with severe acute pancreatitis had elevated levels of cell-free DNA and MPO-DNA conjugates, consistent with NET formation. Neutrophils from mice with pancreatitis were more prone to NET formation and CQ decreased this propensity to form NETs. CQ significantly reduced serum cell-free DNA and citrullinated histone H3 in murine models of pancreatitis, increasing survival in both models. Inhibition of NETs with CQ decreases the severity of acute pancreatitis and improves survival. Translating these findings into clinical trials of acute pancreatitis is warranted.
Changes in beta-catenin expression and activation during progression of primary sclerosing cholangitis predict disease recurrence
Primary sclerosing cholangitis (PSC) is a rare, chronic, cholestatic liver disease characterized by progressive inflammation and fibrosis of the bile ducts. We have previously demonstrated the importance of Wnt/β-catenin signaling in mouse models of PSC. In this study, we wished to determine the clinical relevance of β-catenin localization in patient samples. In livers explanted from patients diagnosed with PSC, the majority (12/16; 75%) lacked β-catenin protein expression. Biopsies from patients post-transplant were classified as recurrent or non-recurrent based on pathology reports and then scored for β-catenin activation as a function of immunohistochemical localization. Despite lack of statistical significance, patients with recurrent primary disease (n = 11) had a greater percentage of samples with nuclear, transcriptionally active β-catenin (average 58.8%) than those with no recurrence (n = 10; 40.53%), while non-recurrence is correlated with β-catenin staining at the cell surface (average 52.63% for non-recurrent vs. 27.34% for recurrent), as determined by three different methods of analysis. β-catenin score and years-to-endpoint are both strongly associated with recurrence status ( p  = 0.017 and p  = 0.00063, respectively). Finally, there was significant association between higher β-catenin score and increased alkaline phosphatase, a marker of biliary injury and disease progression. Thus, β-catenin expression and activation changes during the progression of PSC, and its localization may be a useful prognostic tool for predicting recurrence of this disease.