Is Adjuvant Chemotherapy Necessary for Patients with Deficient Mismatch Repair Gastric Cancer?-Autophagy Inhibition Matches the Mismatched.

PURPOSE: The use of microsatellite instability (MSI) and mismatch repair (MMR) as predictive biomarkers for fluorouracil-based adjuvant chemotherapy in colorectal cancer has been a paradigm shift. However, whether this applies to gastric cancer is questionable. Furthermore, we herein investigated whether and how autophagy plays a role in MSI-relevant chemoresistance. MATERIALS AND METHODS: A total of 929 patients with deficient MMR (dMMR) and proficient MMR (pMMR) gastric cancers who underwent curative-intent gastrectomy were enrolled. We compared clinicopathological variables and survival among dMMR and pMMR cohorts and tested the responses of MSI-high and microsatellite stable (MSS) gastric cancer cell lines to 5-fluorouracil (5-FU) with or without chloroquine, an autophagy inhibitor. RESULTS: We identified an 8.9% prevalence of dMMR cases (83 out of 929) in our cohort. This was associated with old age, tumor site at the distal stomach, an intestinal phenotype, fewer nodal metastasis, and early pathological stages. MMR was an independent prognostic factor after multivariate adjustment. Overall survival (OS) of dMMR patients was better than that of the pMMR patients but was only applicable to stage III patients. There was no difference in OS between dMMR patients treated with or without adjuvant chemotherapy, although the latter showed more medical morbidities. The MSI-high gastric cancer cell lines, versus the MSS counterparts, displayed increased resistance to 5-FU and increased autophagy. Interestingly, autophagy inhibition abrogated the chemoresistance. CONCLUSION: Our data show that fluorouracil-based adjuvant chemotherapy does not work for dMMR cases, if not worse. Autophagy inhibition and/or immune checkpoint inhibition might be promising alternative strategies for gastric cancer treatment. IMPLICATIONS FOR PRACTICE: The use of microsatellite instability (MSI) and mismatch repair (MMR) as predictive biomarkers for adjuvant chemotherapy in colorectal cancer has caused a paradigm shift in cancer therapy, although its implications in gastric cancer are still questionable. The data obtained in the current study indicate that MSI-MMR is an independent prognostic factor for gastric cancer. Standard fluorouracil-based adjuvant chemotherapy did not work for deficient MMR cases, and was likely worse. Instead, strategies like autophagy inhibition and/or immune checkpoint inhibition should be taken into consideration in the future.

Regulation of autophagy in leukocytes through RNA N6-adenosine methylation in chronic kidney disease patients.

Patients with chronic kidney diseases have multiple cellular dysfunctions leading to increased atherosclerosis, impaired immunity, and disturbed metabolism. However, it is unclear what is the fundamental signaling served as a marker or as a mediator for the dysregulated function in their leukocytes or tissues. Here we hypothesized that the N6-Methyladenosine (m6A) modification of the RNA in the leukocytes is responsible for the cellular dysfunction in chronic kidney diseases. Patients with chronic kidney diseases had significantly less m6A abundances in leukocytes and elevated RNA demethylase FTO proteins. The uremic toxin, indoxyl sulfate, activated the autophagy flux through modulation of FTO and m6A modifications in RNA. Notably, knockdown of FTO or inhibit the m6A by 3-deazaadenosine blocks the effects of indoxyl sulfate on autophagy activation in cells. These findings provide new insights into the mechanisms underlying chronic kidney disease-associated cellular dysfunction. Targeting RNA m6A modification may be a novel strategy for the treatment of chronic kidney diseases and autophagy.

Serum asprosin levels and bariatric surgery outcomes in obese adults.

BACKGROUND/OBJECTIVES: Asprosin is a novel fasting-induced glucogenic and orexigenic protein hormone. The clinical function of asprosin in obesity is currently unknown. This study investigated the association between asprosin abundance and the outcome of bariatric surgery. SUBJECTS/METHODS: Patients with body mass index more than 35 kg/m2 were recruited for the Obesity and Clock for Elegant Aging Registry in 2011-2016. Body weight changes, blood sugar, and asprosin were assessed in 117 patients receiving bariatric surgery and 57 non-obese subjects as normal control. Primary outcomes of excess weight loss percentage at 6 months after bariatric surgery were determined at follow-up. RESULTS: Asprosin levels were significantly higher in obese patients than in non-obese subjects (2360 ± 5094 vs. 307 ± 832 ng/ml, p < 0.0001). Multivariate analyses showed a significant association of asprosin abundance with excess body weight loss percentage at 6 months after surgery (p < 0.0001). After adjusted for age, sex, smoking, HbA1c, cholesterol, and triglyceride, serum asprosin level was the only independent predictor of 6 months excess weight loss percentage after bariatric surgery. Asprosin levels decreased significantly 6 months after bariatric surgery (162.2 ± 169.1 ng/ml). Furthermore, there was no association between asprosin and serum glucose levels in our study. CONCLUSION: This study provides novel evidence that higher asprosin concentrations before bariatric surgery were associated with the weight reduction magnitude at 6 months after surgery. Further studies are warranted to investigate whether asprosin has direct functions to modulate body weight regulation in humans after bariatric surgery.

Serum microRNA panels predict bariatric surgery outcomes.

OBJECTIVE: The weight losses after bariatric surgery are modulated by multiple factors in people with obesity. MicroRNAs (miRNAs) have been reported to show significant regulatory roles in adipose tissue. However, a serum miRNA signature to serve as a biomarker of sustained weight losses following bariatric surgery has not yet been established. METHODS: MiRNA microarray was used to identify differentially expressed miRNAs in the serum of patients with an effective response after bariatric surgery compared with those without. Excess weight loss > 55% at 6 months after surgery was defined as an effective response. RESULTS: Three miRNAs were shown to have a significantly differential expression between patients with or without an effective response following bariatric surgery. The miR-31-5p was downregulated, whereas miR-328-3p and miR-181a-5p were upregulated in the patients with effective responses compared with those without effective responses. Panels of the serum ratios of miR-328-3p/miR-31-5p or miR-181a-5p/miR-31-5p and individual BMI value exhibited good performance in preoperative prediction of treatment effectiveness. Bioinformatic analysis depicted that predicted targets of these miRNAs were involved in the regulation of the AMP-activated protein kinase signaling pathway. CONCLUSIONS: A circulating miRNA signature with clinical variables (BMI) can be a clinical biomarker to predict effectiveness following bariatric surgery.

Autophagy in Chronic Kidney Diseases.

Autophagy is a cellular recycling process involving self-degradation and reconstruction of damaged organelles and proteins. Current evidence suggests that autophagy is critical in kidney physiology and homeostasis. In clinical studies, autophagy activations and inhibitions are linked to acute kidney injuries, chronic kidney diseases, diabetic nephropathies, and polycystic kidney diseases. Oxidative stress, inflammation, and mitochondrial dysfunction, which are implicated as important mechanisms underlying many kidney diseases, modulate the autophagy activation and inhibition and lead to cellular recycling dysfunction. Abnormal autophagy function can induce loss of podocytes, damage proximal tubular cells, and glomerulosclerosis. After acute kidney injuries, activated autophagy protects tubular cells from apoptosis and enhances cellular regeneration. Patients with chronic kidney diseases have impaired autophagy that cannot be reversed by hemodialysis. Multiple nephrotoxic medications also alter the autophagy signaling, by which the mechanistic insights of the drugs are revealed, thus providing the unique opportunity to manage the nephrotoxicity of these drugs. In this review, we summarize the current concepts of autophagy and its molecular aspects in different kidney cells pathophysiology. We also discuss the current evidence of autophagy in acute kidney injury, chronic kidney disease, toxic effects of drugs, and aging kidneys. In addition, we examine therapeutic possibilities targeting the autophagy system in kidney diseases.