Research Progress of Endoplasmic Reticulum Stress PERK-eIF2α-AFT4-CHOP Signaling Pathway in Hematological Malignancies / 肿瘤防治研究

The biosynthesis and maturation of proteins are primarily regulated by the endoplasmic reticulum in its physiological state. Thus, the disruption of physiological homeostasis initiates the buildup of unfolded and misfolded proteins in the endoplasmic reticulum, resulting in endoplasmic reticulum stress (ERS) and unfolded protein response (UPR). One of the important pathways by which UPR maintains intracellular homeostasis under ERS is activating protein kinase R-like endoplasmic reticulum kinase (PERK). The activation of the PERK pathway stimulates eukaryotic translation initiation factor 2 subunit-α (eIF2α) phosphorylation and the selective translation of active transcription factor 4 (ATF4), and PERK induces cell apoptosis by directly binding to the promoter of pro-apoptotic transcription factor C/EBP homologous protein (CHOP). This signaling pathway is also one of the important mechanisms by which UPR participates in the regulation of hematological malignancies and immune cells in a tumor microenvironment. This article provides an overview of advancements in research into the PERK-eIF2α-ATF4-CHOP signaling pathway in hematological malignancies and the potential therapeutic benefits of targeting this signaling pathway.

ORP8 acts as a lipophagy receptor to mediate lipid droplet turnover

Lipophagy, the selective engulfment of lipid droplets (LDs) by autophagosomes for lysosomal degradation, is critical to lipid and energy homeostasis. Here we show that the lipid transfer protein ORP8 is located on LDs and mediates the encapsulation of LDs by autophagosomal membranes. This function of ORP8 is independent of its lipid transporter activity and is achieved through direct interaction with phagophore-anchored LC3/GABARAPs. Upon lipophagy induction, ORP8 has increased localization on LDs and is phosphorylated by AMPK, thereby enhancing its affinity for LC3/GABARAPs. Deletion of ORP8 or interruption of ORP8-LC3/GABARAP interaction results in accumulation of LDs and increased intracellular triglyceride. Overexpression of ORP8 alleviates LD and triglyceride deposition in the liver of ob/ob mice, and Osbpl8-/- mice exhibit liver lipid clearance defects. Our results suggest that ORP8 is a lipophagy receptor that plays a key role in cellular lipid metabolism.

Research Advances on CD47 Molecules in Tumor Microenvironment of Diffuse Large B-cell Lymphoma / 肿瘤防治研究

Diffuse large B-cell lymphoma (DLBCL) is a common, highly aggressive and heterogeneous hematologic malignancy in adults. Patients with DLBCL have substantially differences in molecular biological characteristics, clinical manifestations, and prognosis. Increasing evidence shows that the tumor microenvironment plays an important role in the occurrence and development of DLBCL. CD47, an integrin related protein, is overexpressed in DLBCL cells and plays a key role in immune escape of lymphoma. This work reviews the research progress of CD47 in DLBCL TME in terms of CD47-related signal pathway, CD47 role in DLBCL TME, and therapeutic strategies targeting CD47 in DLBCL TME.