NCX1/Ca2+ promotes autophagy and decreases bortezomib activity in multiple myeloma through non-canonical NFκB signaling pathway.

Although bortezomib (BTZ) is the cornerstone of anti-multiple myeloma (MM) therapy, the inevitable primary and secondary drug resistance still seriously affects the prognosis of patients. New treatment strategies are in need. Sodium-calcium exchanger 1 (NCX1) is a calcium-permeable ion transporter on the membrane, and our previous studies showed that low NCX1 confers inferior viability in MM cells and suppressed osteoclast differentiation. However, the effect of NCX1 on BTZ sensitivity of MM and its possible mechanism remain unclear. In this study, we investigated the effect of NCX1 on BTZ sensitivity in MM, focusing on cellular processes of autophagy and cell viability. Our results provide evidence that NCX1 expression correlates with MM disease progression and low NCX1 expression increases BTZ sensitivity. NCX1/Ca2+ triggered autophagic flux through non-canonical NFκB pathway in MM cells, leading to attenuated the sensitivity of BTZ. Knockdown or inhibition of NCX1 could potentiate the anti-MM activity of BTZ in vitro and vivo, and inhibition of autophagy sensitized NCX1-overexpressing MM cells to BTZ. In general, this work implicates NCX1 as a potential therapeutic target in MM with BTZ resistance and provides novel mechanistic insights into its vital role in combating BTZ resistance.

Causal relationship between genetically predicted type 2 diabetes mellitus and male infertility.

Background: Diabetes mellitus (DM) stands as the most prevalent endocrine abnormality affecting the physiological systems and organs and impairing the male reproductive functions. Type 2 Diabetes Mellitus (T2DM), accounting for about 90-95% of DM, is closely associated with male infertility. However, the magnitude of the causal relationships between T2DM and male infertility remains unclear. The current investigation was to explore the causal relationship between T2DM and male infertility utilizing the Mendelian Randomization (MR) analysis. Methods: A two-sample MR (2SMR) analysis was conducted to investigate the causal relationship between T2DM and male infertility in the European population from the genome-wide association study (GWAS) summary data that was publicly accessible. GWAS for T2DM and male infertility were extracted from the IEU Open GWAS Project database, with the resulting data encompassing 680 cases and 72,799 controls as the outcome data. Five MR methods were employed for the 2SMR analyses, namely the MR-Egger, weighted median estimation (WME), weighted mode (WM), inverse-variance weighted (IVW), and simple mode. The primary analytical technique utilized in this study was the IVW method, and a multivariate MR analysis was executed to examine the potential mediating influences of T2DM on male infertility. Results: Following were the odds ratios (ORs) and associated 95% CIs derived from IVW (fixed effects), MR-Egger, WM, WME, and simple mode approaches: 0.824 (95% CI 0.703-0.966), 0.726 (95% CI 0.527-1.001), 0.827 (95% CI 0.596-1.150), 0.841 (95% CI 0.654-1.082), and 0.875 (95% CI 0.544-1.405), respectively. The outcomes of the heterogeneity tests were P=0.378 and P=0.384, respectively, implying no heterogeneity. Egger-intercept outcomes were P=0.374, highlighting the absence of pleiotropy. The stability of the results was affirmed through the leave-one-out analysis. Notably, all F-values surpassed 10, indicating the absence of weak bias attributed to instrument variables(IVs). Conclusions: This research furnishes evidence supporting a causal association between T2DM and male infertility. These insights offer a foundation for future investigations aiming to establish the association between genetically predicted T2DM and male infertility. These outcomes suggest the significance of active monitoring and proactive measures for preventing infertility in male individuals with T2DM. Furthermore, careful consideration is required for individuals of reproductive age to prevent and treat T2DM.

SSBP1 is a novel prognostic marker and promotes disease progression via p38MAPK signaling pathway in multiple myeloma.

Multiple myeloma (MM) remains an incurable disease. Identification of meaningful co-expressed gene clusters or representative biomarkers of MM may help to identify new pathological mechanisms and promote the development of new therapies. Here, we performed weighted sgene co-expression network analysis and a series of bioinformatics analysis to identify single stranded DNA binding protein 1 (SSBP1) as novel hub gene associated with MM development and prognosis. In vitro, CRISPR/cas9 mediated knockdown of SSBP1 can significantly inhibit the proliferation of MM cells through inducing apoptosis and cell cycle arrest in G0/G1 phase. We also found that decreased SSBP1 expression significantly increased mitochondrial reactive oxygen species (mtROS) generation and the level of phosphorylated p38MAPK. Furthermore, it was further verified that disruption of SSBP1 expression could inhibit the tumor growth via p38MAPK pathway in a human myeloma xenograft model. In summary, our study is the first to demonstrate that SSBP1 promotes MM development by regulating the p38MAPK pathway.

[Correlation between Serum Interleukin-33, ß2-Microglobulin Levels and DS Stage in Patients with Multiple Myeloma].

OBJECTIVE: To investigate the correlation between serum interleukin-33 (IL-33), ß2microglobulin (ß2-MG) levels and Durie-Salmon (DS) stage in patients with multiple myeloma (MM). METHODS: 100 MM patients admitted to the First Affiliated Hospital of Fujian Medical University from March 2019 to January 2021 were selected and divided into stage I, stage II and stage III groups according to the DS staging system. A baseline data questionnaire of patients was designed, then the relevant baseline data and laboratory test results of patients were recorded. The levels of serum IL-33 and ß2-MG of all patients were detected, and the correlation between serum IL-33, ß2-MG levels and DS stage of MM patients was analyzed. RESULTS: Among the 100 patients with MM, there were 32 cases in stage I, 39 cases in stage II and 29 cases in stage III. The levels of serum CRP and ß2-MG of patients in stage III were significantly higher than those of patients in stage I and II, and the levels of serum CRP and ß2-MG of patients in stage II were significantly higher than those of patients in stage I, the differences were statistically significant (P <0.05). The level of serum IL-33 of patients in stage III was significantly lower than that of patients in stage I and II, and the level of serum IL-33 of patients in stage II was significantly lower than that of patients in stage I, the differences were statistically significant (P <0.05). There was no statistical significant difference in other data between groups (P >0.05). Kendall's tau-b correlation analysis showed that the levels of serum CRP and ß2-MG were positively correlated with DS stage in MM patients (r =0.534, 0.776), the level of serum IL-33 was negatively correlated with DS stage in MM patients (r =-0.759). Ordered logistic regression analysis and forest plot showed that the low level of serum IL-33 and the high level of ß2-MG were the influencing factors of high DS stage in MM patients (P <0.05 ). CONCLUSION: DS stage of MM patients is closely related to the levels of serum IL-33 and ß2-MG, that is, the lower the serum IL-33 level and the higher the ß2-MG level, and the higher the DS stage of MM patients.

NCX1 disturbs calcium homeostasis and promotes RANKL-induced osteoclast differentiation by regulating JNK/c-Fos/NFATc1 signaling pathway in multiple myeloma.

Although several types of calcium channels abnormalities have been shown to promote myeloma bone disease (MBD), the relationship between Na+/Ca2+ exchanger 1 (NCX1) and MBD remains unexplored. Here, we examined the role of NCX1 in the development of multiple myeloma (MM), with a special focus on the underlying effects involved osteoclast differentiation. Firstly, we detected NCX1 protein highly expressed in BM tissues of MM patients, and its expression was positively correlated with serum calcium and the percentage of BM CD138+ cells. In vitro, NCX1 suppression with the inhibitor KB-R7943 reduced cell viability of MM cells and caused apoptosis. Extracellular high Ca2+ environment increased the level of intracellular Ca2+ in MM cells through gating the calcium influx, with subsequently promoting the expression of NCX1 and osteoclastogenesis-related genes (receptor activator of nuclear factor-κB (RANKL), nuclear factor of activated T cell cytoplasmic 1 (NFATc1), and proto-oncogene Fos (c-Fos). This phenomenon could be reversed by KB-R7943 or calcium chelation. Furthermore, NCX1 overexpression in MM cells accelerated osteoclastogenesis, while NCX1 knockdown or suppression resulted in the opposite effect. Mechanistically, we further investigated the related mechanisms of NCX1 regulating osteoclast differentiation using RNA sequencing, western blotting and Enzyme linked immunosorbent assay, and found that NCX1 modulated osteoclast differentiation in MM though JNK/c-Fos/NFATc1 signaling pathway. In conclusion, the Ca2+/NCX1-mediated signaling participates in the osteoclasts-myeloma cell interactions, which represents a promising target for future therapeutic intervention in MBD.

Regulatory role of DEPTOR­mediated cellular autophagy and mitochondrial reactive oxygen species in angiogenesis in multiple myeloma.

DEPTOR, an inhibitor of mammalian target of rapamycin (mTOR), is essential for the survival of multiple myeloma (MM) cells. The expression level of DEPTOR is closely related to the prognosis of patients with MM treated with the antiangiogenic agent thalidomide; however, its role in the regulation of angiogenesis has not yet been elucidated. In the present study, the expression levels of DEPTOR and vascular endothelial growth factor (VEGF), and the microvessel density (MVD) of bone marrow (BM) from patients with MM assessed. DEPTORoverexpression plasmid or CRISPR­associated protein 9 (Cas9) and single guided RNAs (sgRNAs) were used to modulate DEPTOR expression. The DEPTOR­mediated angiogenic effects were assessed using a tube formation assay of human umbilical vein endothelial cells (HUVECs) cultured in the collected conditioned medium from MM cell lines with different expression levels of DEPTOR. It was found that the expression level of DEPTOR negatively correlated with the VEGF level and BM MVD in MM. Autophagic activity was regulated by DEPTOR expression, but was not related to thalidomide­binding protein CRBN, which is required for thalidomide to play an anti­tumor and antiangiogenic role in MM cells. The disruption of DEPTOR protein decreased cellular autophagy, increased VEGF expression in MM cells, and inhibited the tube formation of HUVECs, while a high expression of DEPTOR exerted the opposite effect. Moreover, targeting DEPTOR also resulted in the production of mitochondrial reactive oxygen species (mtROS), the phosphorylation of nuclear factor­κB (NF­κB) and an increase in interleukin 6 (IL­6) secretion. Of note, these effects are fully abrogated by treatment with autophagy activator (SMER28) or mitochondrial­specific antioxidant (Mito­TEMPO). Taken together, the present study demonstrates the role of DEPTOR in the regulation of autophagy/mtROS and subsequent angiogenesis. The results provide a novel mechanism for the further understanding of the therapeutic effects of thalidomide on MM.

Vγ9Vδ2 T cells inhibit immature dendritic cell transdifferentiation into osteoclasts through downregulation of RANK, c­Fos and ATP6V0D2.

Osteoimmunological studies have revealed that T cells exert a powerful impact on the formation and activity of osteoclasts and bone remodeling. Evidence demonstrates that immature dendritic cells (iDCs) are more efficient transdifferentiating into osteoclasts (OCs) than monocytes. However, whether Vγ9Vδ2 T (γδ T) cells stimulate or inhibit iDC transdifferentiation into OCs has never been reported. The aim of the present study was to investigate the effects of γδ T cells on this transdifferentiation process. γδ T cells and iDCs were isolated from the peripheral blood of healthy volunteers separately and were co­cultured with Transwelll inserts, with γδ T cells in the upper chamber and iDCs in the lower chamber. IDCs were treated with macrophage­colony stimulating factor and receptor activator of nuclear factor­κB (RANK) ligand. Tartrate resistant acid phosphatase (TRAP) assay and dentine resorption assay were performed to detect OC formation and their resorption capacity, respectively. The mRNA expression of OCs was examined using a microarray and real time­quantitative polymerase chain reaction to trace the changes during iDC transdifferentiation into OCs. The results demonstrated that γδ T cells significantly inhibited the generation of the TRAP­positive OCs from iDCs and their resorption capacity. The microarray analysis identified decreased expression level of Fos proto­oncogene AP­1 transcription factor subunit (c­Fos), ATPase H+ transporting V0 subunit d (ATP6V0D2) and cathepsin K when iDCs were co­cultured with γδ T cells. These genes are associated with OC differentiation, indicating that γδ T cells suppressed iDCs osteoclastogenesis by downregulation of the RANK/c­Fos/ATP6V0D2 signaling pathway. The present findings provide novel insights into the interactions between human γδ T cells and iDCs, and demonstrate that γδ T cells are capable of inhibiting OC formation and their activity via downregulation of genes associated with OC differentiation.

[Effects of Autophagy Regulating Drugs on Proliferation, Apoptosis and Autophagy of Multiple Myeloma Cells].

OBJECTIVE: To investigate the effects of autophagy activator (rapamycin, RAPA) and autophagy inhibitor (hydroxychloroquine, HCQ and 3-methyl adenine, 3-MA) on the proliferation, apoptosis and autophagy of multiple myeloma cell line of RPMI8226. METHODS: RPMI8226 cells were treated with autophagy regulating drugs of different concentrations. The proliferation and apoptosis of cells were determined by CCK-8 and flow cytometry, respectively. The expressions of apoptosis-related proteins BCL-2, caspase-3 and PARP protein were assessed by Western blot. Autophagy was detected by monodansylcadaverine staining. Autophagic protein (LC-3b) and apoptosis-related proteins (caspase-3, PARP and BCL-2) were analyzed by Western blot. RESULTS: RAPA and HCQ inhibited the proliferation of RPMI8226 in a concentration- and time-dependent manner, and increased the apoptosis. However, 3-MA did not show significantly inhibitory effect on the proliferation and apoptosis of RPMI8226. MDC staining showed that the more autophagic vacuoles could be detected in the higher concentration of RAPA, but the less autophagic vacuoles in the higher concentration of HCQ and 3-MA. Western blot showed that RAPA increased the expression of LC3-II/LC3-I, caspase-3 and PARP, but inhibited the expression of BCL-2. HCQ inhibited the expression of LC3-II/LC3-I and BCL-2, but increased the expression of caspase-3 and PARP. 3-MA inhibited the expression of LC3-II/LC3-I, but had no effect on the expression of caspase-3, PARP or BCL-2. CONCLUSION: Rapamycin can inhibit the proliferation, induce apoptosis and autophagy of RPMI 8226, the hydroxychloroquine can inhibit autophagy and proliferation of RPMI 8226, and induce apoptosis, the 3-MA can inhibit autophagy of RPMI 8226, but hardly has any effects on proliferation and apoptosis of RPMI 8226 cells.