Autophagy in Hematological Malignancies: Molecular Aspects in Leukemia and Lymphoma

Single-cell sequencing and spatial transcriptomics reveal FAS+ T cell and autophagy-related signatures predicting chemoimmunotherapy response in diffuse large B-cell lymphoma patients

Current subtyping methods of diffuse large B-cell lymphoma (DLBCL) could not satisfy the clinical demands for risk assessment and prognostic prediction. We aimed to investigate the prognostic effect of autophagy-related genes (ARGs) in DLBCL. Transcriptomic data of 1,409 DLBCL patients, 531 healthy controls (HCs), and single-cell sequencing data of 4 DLBCL were included. Validation involved spatial transcriptomics from 10 DLBCL patients and 110 DLBCL proteomic data from a local cohort. We identified 153 differentially expressed ARGs between DLBCL patients (n=48) and HCs (n=531), classifying 414 DLBCL patients into two subtypes based on autophagy heterogeneity. Subtype I, characterized by upregulated T regulatory (Treg) cells (P<0.0001) and T follicular helper (Tfh) cells (P=0.0012), showed a superior prognosis (P=0.035). Eight prognostic ARGs were selected to construct an autophagy-related model, dividing patients into low- and high-risk groups. Kaplan-Meier survival analysis revealed significantly better outcomes for the low-risk group in both the discovery (P<0.0001) and validation cohorts (P=0.0041). High-risk patients exhibited elevated IDO1 (P=0.042) and LAG3 (P<0.001) levels. Among the eight signature proteins, higher FAS was further verified to indicate a better prognosis in the local cohort (n=110) using antibody array (P=0.0083). FAS was primarily expressed in T cells such as Treg and Tfh cells and was elevated in non-progressive disease patients. FAS-positive T cells showed increased interferon-gamma (normalized enrichment score (NES)=2.196, FDR<0.0001) and alpha (NES=1.836, FDR<0.01) response activities. We constructed an autophagy-related model and identified FAS as a prognostic biomarker. FAS+ Treg and Tfh cell-enriched TME indicated a favorable prognosis.

Hypoxia-initiated Cysteine-rich protein 61 secretion promotes chemoresistance of acute B lymphoblastic leukemia cells

The drug resistance is a major obstacle in acute B-lymphoblastic leukemia (B-ALL) treatment. Our previous study has indicated that increased levels of Cysteine-rich protein 61 (Cyr61) in the bone marrow can mitigate the chemosensitivity of B-ALL cells, though the specific source of Cyr61 in the bone marrow remains unknown. In this study, we aimed to investigate whether hypoxia can induce Cyr61 production in B-ALL cells, delineates the underlying mechanisms, and evaluates the effect of Cyr61 on the chemosensitivity of B-ALL cells under hypoxia conditions. The results indicate that hypoxia promotes Cyr61 production in B-ALL cells by activating the NF-κB pathway. Increased Cyr61 expression appears to reduce the chemosensitivity of B-ALL cell to vincristine (VCR) and daunorubicin (DNR) through autophagy under hypoxia. Notably, inhibition of Cyr61 restores the chemosensitivity of B-ALL cells to both chemotherapeutic agents. This study is the first time to report that hypoxia decreases the chemosensitivity of B-ALL cells by inducing Cyr61 production, suggesting that targeting Cyr61 or its associated pathways could potentially improve the clinical response of B-ALL patients.

Lysosomes in Stem Cell Quiescence: A Potential Therapeutic Target in Acute Myeloid Leukemia

Lysosomes are cellular organelles that regulate essential biological processes such as cellular homeostasis, development, and aging. They are primarily connected to the degradation/recycling of cellular macromolecules and participate in cellular trafficking, nutritional signaling, energy metabolism, and immune regulation. Therefore, lysosomes connect cellular metabolism and signaling pathways. Lysosome's involvement in the critical biological processes has rekindled clinical interest towards this organelle for treating various diseases, including cancer. Recent research advancements have demonstrated that lysosomes also regulate the maintenance and hemostasis of hematopoietic stem cells (HSCs), which play a critical role in the progression of acute myeloid leukemia (AML) and other types of cancer. Lysosomes regulate both HSCs' metabolic networks and identity transition. AML is a lethal type of blood cancer with a poor prognosis that is particularly associated with aging. Although the genetic landscape of AML has been extensively described, only a few targeted therapies have been produced, warranting the need for further research. This review summarizes the functions and importance of targeting lysosomes in AML, while highlighting the significance of lysosomes in HSCs maintenance.