Autophagy is a conserved process for self-degradation and provides cells with a rescue mechanism to respond to circumstances such as stress and starvation. The role of autophagy in cancer is extremely complex and often paradoxical. Most of the related published studies on tumors are always focused on cancer cells. However, present studies gradually noticed the significance of autophagy in the tumor microenvironment. These studies demonstrate that autophagy and immunity work synergistically to affect tumor progression, indicating that autophagy could become a potential target for cancer immunotherapy. Therefore, it is crucial to clarify the correlation between autophagy and various tumor-infiltrating immune cells in the tumor microenvironment. The context-dependent role of autophagy is critical in the design of therapeutic strategies for cancer.

Introduction: Severe obesity is often present with non-alcoholic fatty liver disease (NAFLD) and obstructive sleep apnea (OSA). Emerging researches suggest OSA plays an important role in NAFLD development and progression while the relationship between OSA and NAFLD is still conflicting. The interaction of OSA and NAFLD should be further evaluated as obesity surges. The purpose of this study was to assess the prevalence of OSA and NAFLD in patients with obesity undergoing bariatric surgery and evaluate the association between OSA and severity of NAFLD. Methods: 141 patients with severe obesity undergoing preoperative polysomnography and intraoperative liver biopsy during bariatric surgery were investigated. Clinical, anthropometric variables, liver enzymes, fasting blood glucose, fasting serum insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) were measured. The severity of NAFLD was assessed by degree of steatosis, ballooning, intralobular inflammation, and NAFLD activity score. The diagnosis and severity assessment of OSA was based on an apnea/hypopnea index (AHI). Results: OSA was diagnosed in 127 (90.07%), NAFLD in 124 (87.94%), and non-alcoholic steatohepatitis in 72 (51.06%) patients. There was a statistical difference in BMI, waist circumstance, neck circumstance, high-density lipoprotein cholesterol, fasting insulin, and HOMA-IR among the three groups divided by the severity of AHI. In addition, the distribution of hepatic steatosis grades among the three groups was statistically different (p = 0.025). AHI was significantly associated with HOMA-IR and hepatic steatosis when assessing the association between OSA parameters and liver histology in NAFLD (p < 0.05). Patients with steatosis of grades 1–3 had significantly elevated aspartate aminotransferase, alanine aminotransferase, gamma glutamyl transferase, triglycerides, fasting insulin, fasting glucose, HOMA-IR, and AHI compared with the patients with steatosis of grade 0. In a multivariable logistic analysis, the positive association between AHI and hepatic steatosis attenuated after adjusting for HOMA-IR. Conclusion: Prevalence of OSA and NAFLD was high in patients with obesity eligible for bariatric procedures. HOMA-IR, but not AHI, was an independent risk factor for hepatic steatosis in this population.

Pancreatic ductal adenocarcinoma (PDAC) represents one of the deadliest malignancies. Elevated regulatory T cell (Treg) infiltration has a potent immunosuppressive function in tumor biology, which contributes to low survival in PDAC. Nonetheless, the crosstalk between malignant cells and tumor-infiltrating Tregs in PDAC is not well understood. Here, clinical data demonstrates that the insulin-like growth factor binding protein 2 (IGFBP2) is associated with Treg accumulation in the microenvironment of PDAC in humans. Additionally, IGFBP2 increases Treg infiltration in the tumor microenvironment and promotes disease progression in mouse PDAC. Bioinformatic analysis and mechanistic assessment reveals IGFBP2 upregulated indoleamine 2, 3-dioxygenase (IDO) by activating signal transducer and activator of transcription 3 (STAT3) signaling in PDAC cells, thus inducing Treg differentiation and an immunosuppressive tumor microenvironment. These findings provide mechanistic insights into an important molecular pathway that promotes an immunosuppressive microenvironment, which suggests the IGFBP2 axis as a potential target for improved immune response in PDAC.

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant cancer with a poor prognosis, and effective treatments for PDAC are lacking. In this study, we hypothesized that miR-506 promotes antitumor immune response in PDAC by reprogramming tumor-associated macrophages toward an M1 phenotype to reverse its immunosuppressive tumor microenvironment (TME). First, the relationship between TME and the expression of miR-506 was assessed using clinical samples. Our results provided evidence that lower expression of miR-506 was associated with poor prognosis and immunosuppressive TME in PDAC patients. In addition, miR-506 inhibit the PDAC progression and reversed its immunosuppressive microenvironment in a macrophage-dependent manner. Next, we established a PDAC mouse model by orthotopic injection to further explore the role of miR-506 in vivo. Mechanistic investigations demonstrated that miR-506 could reprogram the polarization of M2-like macrophages toward an M1-like phenotype through targeting STAT3. Meanwhile, miR-506 could also sensitize PDAC to anti-PD-1 immunotherapy, because the tumor microenvironment remodeling effects of miR-506 could reprogram macrophage polarization and subsequently promote cytotoxic T lymphocyte (CTL) infiltration. These findings suggest a relationship between miR-506 and TME, especially M2-like macrophages, thus providing novel insights into mechanisms of tumor progression and potential immunotherapeutic targets for further clinical treatment.

The relationship between mitochondrial architecture and energy homeostasis in adipose tissues is not well understood. In this study, we utilized GCN5L1-knockout mice in white (AKO) and brown (BKO) adipose tissues to examine mitochondrial homeostasis in adipose tissues. GCN5L1, a regulator of mitochondrial metabolism and dynamics, influences resistance to high-fat-diet-induced obesity in AKO but not BKO mice. This resistance is mediated by an increase in mitochondrial cristae that stabilizes oxidative phosphorylation (OXPHOS) complexes and enhances energy expenditure. Our protein-interactome analysis reveals that GCN5L1 is associated with the mitochondrial crista complex MICOS (MIC13) and the protease YME1L, facilitating the degradation of MICOS and disassembly of cristae during obesity. This interaction results in decreased OXPHOS levels and subsequent adipocyte expansion. Accumulation of GCN5L1 in the mitochondrial intermembrane space is triggered by a high-fat diet. Our findings highlight a regulatory pathway involving YME1L/GCN5L1/MIC13 that remodels mitochondrial cristae in WAT in response to overnutrition-induced obesity.