Inhibition of CARM1 suppresses proliferation of multiple myeloma cells through activation of p53 signaling pathway

Mitochondria-associated programmed cell death: elucidating prognostic biomarkers, immune checkpoints, and therapeutic avenues in multiple myeloma

Background

Multiple myeloma (MM) is a hematological malignancy characterized by the abnormal proliferation of plasma cells. Mitochondrial dysfunction and dysregulated programmed cell death (PCD) pathways have been implicated in MM pathogenesis. However, the precise roles of mitochondria-related genes (MRGs) and PCD-related genes (PCDRGs) in MM prognosis remain unclear.

Methods

Transcriptomic data from MM patients and healthy controls were analyzed to identify differentially expressed genes (DEGs). Candidate genes were selected by intersecting DEGs with curated lists of MRGs and PCDRGs. Univariate Cox, least absolute shrinkage and selection operator (LASSO), multivariate Cox, and stepwise regression analyses identified prognostic genes among the candidates. A risk model was constructed from these genes, and patients were stratified into high- and low-risk groups for survival analysis. Independent prognostic factors were incorporated into a nomogram to predict MM patient outcomes. Model performance was evaluated using calibration curves, receiver operating characteristic (ROC) analysis, and decision curve analysis (DCA). Finally, associations between prognostic genes and immune cell infiltration/drug responses were explored.

Results

2,192 DEGs were detected between MM and control samples. 30 candidate genes were identified at the intersection of DEGs, 1,136 MRGs, and 1,548 PCDRGs. TRIAP1, TOMM7, PINK1, CHCHD10, PPIF, BCL2L1, and NDUFA13 were selected as prognostic genes. The risk model stratified patients into high- and low-risk groups with significantly different survival probabilities. Age, gender, ISS stage, and risk score were independent prognostic factors. The nomogram displayed good calibration and discriminative ability (AUC) in predicting survival, with clinical utility demonstrated by DCA. 9 immune cell types showed differential infiltration between MM and controls, with significant associations to risk scores and specific prognostic genes. 57 drugs, including nelarabine and vorinostat, were predicted to interact with the prognostic genes. Ultimately, qPCR in clinical samples from MM patients and healthy donors validated the expression levels of the seven key prognostic genes, corroborating the bioinformatic findings.

Conclusion

Seven genes (TRIAP1, TOMM7, PINK1, CHCHD10, PPIF, BCL2L1, NDUFA13) involved in mitochondrial function and PCD pathways were identified as prognostic markers in MM. These findings provide insights into MM biology and prognosis, highlighting potential therapeutic targets.

Interference with PLA2G16 promotes cell cycle arrest and apoptosis and inhibits the reprogramming of glucose metabolism in multiple myeloma cells by modulating the Hippo/YAP signaling pathway

Multiple myeloma, which is a clonal plasma cell tumor, derives from a postmitotic lymphoid B-cell lineage and remains untreatable. Group XVI phospholipase A2 (PLA2G16) can either be a tumor suppressor or an oncogene in different types of cancer. This study was intended to explore the role of PLA2G16 in multiple myeloma and to reveal the reaction mechanism. The mRNA and protein expressions of PLA2G16 in human bone marrow stromal cell line HS-5 and multiple myeloma cells were assessed using reverse transcription-quantitative PCR and western blot. The transfection efficacy of sh-PLA2G16 and oe-YAP was examined using reverse transcription-quantitative PCR and western blot. Through cell counting kit-8 assay and 5-ethynyl-2'- deoxyuridine staining, multiple myeloma cell viability and proliferation were detected. Flow cytometry was used to measure cell apoptosis and cell cycle distribution. Oxygen consumption rate, the activities of mitochondrial respiratory chain complexes I-V, and the activity of caspase-3 were estimated with Seahorse XF24 analyzer, oxidative phosphorylation activity assay kit, and caspase-3 assay kit, respectively. Lactate production and glucose consumption were evaluated usingcorresponding assay kits. Western blot was employed to meaure proteins associated with cell cycle, glycolysis, pentose phosphate pathway as well as Hippo/YAP signaling pathway. In this study, PLA2G16 expression was greatly increased in multiple myeloma cells and PLA2G16 silence inhibited cell proliferation, promoted cell apoptosis, facilitated cell cycle arrest, and suppressed the reprogramming of glucose metabolism in multiple myeloma. It was also identified that PLA2G16 depletion inhibited the Hippo/YAP signaling pathway. Further experiments revealed that the overexpression of YAP partially reversed the inhibitory effects of PLA2G16 silence on multiple myeloma cell malignant development and the reprogramming of glucose metabolism. Collectively, PLA2G16 silence impeded multiple myeloma progression and inhibited glucose metabolism reprogramming by blocking the Hippo/YAP signaling pathway.

Targeting hematological malignancies with isoxazole derivatives

Compounds with a heterocyclic isoxazole ring are well known for their diverse biologic activities encompassing antimicrobial, antipsychotic, immunosuppressive, antidiabetic and anticancer effects. Recent studies on hematological malignancies have also shown that some of the isoxazole-derived compounds feature encouraging cancer selectivity, low toxicity to normal cells and ability to overcome cancer drug resistance of conventional treatments. These characteristics are particularly promising because patients with hematological malignancies face poor clinical outcomes caused by cancer drug resistance or relapse of the disease. This review summarizes the knowledge on isoxazole-derived compounds toward hematological malignancies and provides clues on their mechanism(s) of action (apoptosis, cell cycle arrest, ROS production) and putative pharmacological targets (c-Myc, BET, ATR, FLT3, HSP90, CARM1, tubulin, PD-1/PD-L1, HDACs) wherever known.

Protein arginine methyltransferases (PRMTs): Orchestrators of cancer pathogenesis, immunotherapy dynamics, and drug resistance

Protein Arginine Methyltransferases (PRMTs) are a family of enzymes regulating protein arginine methylation, which is a post-translational modification crucial for various cellular processes. Recent studies have highlighted the mechanistic role of PRMTs in cancer pathogenesis, immunotherapy, and drug resistance. PRMTs are involved in diverse oncogenic processes, including cell proliferation, apoptosis, and metastasis. They exert their effects by methylation of histones, transcription factors, and other regulatory proteins, resulting in altered gene expression patterns. PRMT-mediated histone methylation can lead to aberrant chromatin remodeling and epigenetic changes that drive oncogenesis. Additionally, PRMTs can directly interact with key signaling pathways involved in cancer progression, such as the PI3K/Akt and MAPK pathways, thereby modulating cell survival and proliferation. In the context of cancer immunotherapy, PRMTs have emerged as critical regulators of immune responses. They modulate immune checkpoint molecules, including programmed cell death protein 1 (PD-1), through arginine methylation. Drug resistance is a significant challenge in cancer treatment, and PRMTs have been implicated in this phenomenon. PRMTs can contribute to drug resistance through multiple mechanisms, including the epigenetic regulation of drug efflux pumps, altered DNA damage repair, and modulation of cell survival pathways. In conclusion, PRMTs play critical roles in cancer pathogenesis, immunotherapy, and drug resistance. In this overview, we have endeavored to illuminate the mechanistic intricacies of PRMT-mediated processes. Shedding light on these aspects will offer valuable insights into the fundamental biology of cancer and establish PRMTs as promising therapeutic targets.