scholarly journals Mitochondrial Functions, Energy Metabolism and Protein Glycosylation are Interconnected Processes Mediating Resistance to Bortezomib in Multiple Myeloma Cells

Biomolecules ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 696 ◽  
Author(s):  
Daniele Tibullo ◽  
Cesarina Giallongo ◽  
Alessandra Romano ◽  
Nunzio Vicario ◽  
Alessandro Barbato ◽  
...  

The proteasome inhibitor bortezomib (BTZ) has emerged as an effective drug for the treatment of multiple myeloma even though many patients relapse from BTZ therapy. The present study investigated the metabolic pathways underlying the acquisition of bortezomib resistance in multiple myeloma. We used two different clones of multiple myeloma cell lines exhibiting different sensitivities to BTZ (U266 and U266-R) and compared them in terms of metabolic profile, mitochondrial fitness and redox balance homeostasis capacity. Our results showed that the BTZ-resistant clone (U266-R) presented increased glycosylated UDP-derivatives when compared to BTZ-sensitive cells (U266), thus also suggesting higher activities of the hexosamine biosynthetic pathway (HBP), regulating not only protein O- and N-glycosylation but also mitochondrial functions. Notably, U266-R displayed increased mitochondrial biogenesis and mitochondrial dynamics associated with stronger antioxidant defenses. Furthermore, U266-R maintained a significantly higher concentration of substrates for protein glycosylation when compared to U266, particularly for UDP-GlcNac, thus further suggesting the importance of glycosylation in the BTZ pharmacological response. Moreover, BTZ-treated U266-R showed significantly higher ATP/ADP ratios and levels of ECP and also exhibited increased mitochondrial fitness and antioxidant response. In conclusions, our findings suggest that the HBP may play a major role in mitochondrial fitness, driving BTZ resistance in multiple myeloma and thus representing a possible target for new drug development for BTZ-resistant patients.

Blood ◽  
2012 ◽  
Vol 119 (3) ◽  
pp. 810-816 ◽  
Author(s):  
Li Yin ◽  
Michio Kosugi ◽  
Donald Kufe

Abstract The MUC1-C oncoprotein is aberrantly expressed in most multiple myeloma cells. However, the functional significance of MUC1-C expression in multiple myeloma is not known. The present studies demonstrate that treatment of multiple myeloma cells with a MUC1-C inhibitor is associated with increases in reactive oxygen species (ROS), oxidation of mitochondrial cardiolipin, and loss of the mitochondrial transmembrane potential. The MUC1-C inhibitor-induced increases in ROS were also associated with down-regulation of the p53-inducible regulator of glycolysis and apoptosis (TIGAR). In concert with the decrease in TIGAR expression, which regulates the pentose phosphate pathway, treatment with the MUC1-C inhibitor reduced production of NADPH, and in turn glutathione (GSH) levels. TIGAR protects against oxidative stress-induced apoptosis. The suppression of TIGAR and NADPH levels thus contributed to ROS-mediated late apoptosis/necrosis of multiple myeloma cells. These findings indicate that multiple myeloma cells are dependent on MUC1-C and TIGAR for maintenance of redox balance and that targeting MUC1-C activates a cascade involving TIGAR suppression that contributes to multiple myeloma cell death.


2000 ◽  
Vol 111 (4) ◽  
pp. 1118-1121 ◽  
Author(s):  
A. Bellahcene ◽  
I. Van Riet ◽  
C. de Greef ◽  
N. Antoine ◽  
M. F. Young ◽  
...  

2020 ◽  
Vol 18 (3) ◽  
pp. 241-246
Author(s):  
Yu Dan ◽  
Wan Sheng ◽  
Hu Lili

This study aimed to investigate the mechanism of betulinic acid on multiple myeloma cell resistance to bortezomib. To this end, the bortezomib-resistant RPMI-8226-R cells were generated by prolonged treatment of RPMI-8226 cells with increasing concentrations of bortezomib. Based on the measurements of cell viability and colony number, RPMI-8226-R cells exhibited enhanced resistance to bortezomib than RPMI-8226 cells. Treatment with betulinic acid resulted in increased sensitivity of RPMI-8226-R to bortezomib. When RPMI-8226-R cells were co-treated with bortezomib and betulinic acid, there was an increase in apoptosis rate, cleaved caspase-3, cleaved caspase-9 expression and the decrease in p-AKT/AKT and p-mTOR/mTOR levels. These results suggest that betulinic acid enhances the sensitivity of RPMI-8226-R cells to bortezomib by inhibiting the activation of the AKT/mTOR pathway in bortezomib-resistant multiple myeloma cells.


2020 ◽  
Vol 20 (18) ◽  
pp. 2316-2323 ◽  
Author(s):  
Alican Kusoglu ◽  
Bakiye G. Bagca ◽  
Neslihan P.O. Ay ◽  
Guray Saydam ◽  
Cigir B. Avci

Background: Ruxolitinib is a selective JAK1/2 inhibitor approved by the FDA for myelofibrosis in 2014 and nowadays, comprehensive investigations on the potential of the agent as a targeted therapy for haematological malignancies are on the rise. In multiple myeloma which is a cancer of plasma cells, the Interleukin- 6/JAK/STAT pathway is emerging as a therapeutic target since the overactivation of the pathway is associated with poor prognosis. Objective: In this study, our purpose was to discover the potential anticancer effects of ruxolitinib in ARH-77 multiple myeloma cell line compared to NCI-BL 2171 human healthy B lymphocyte cell line. Methods: Cytotoxic effects of ruxolitinib in ARH-77 and NCI-BL 2171 cells were determined via WST-1 assay. The autophagy mechanism induced by ruxolitinib measured by detecting autophagosome formation was investigated. Apoptotic effects of ruxolitinib were analyzed with Annexin V-FITC Detection Kit and flow cytometry. We performed RT-qPCR to demonstrate the expression changes of the genes in the IL-6/JAK/STAT pathway in ARH-77 and NCI-BL 2171 cells treated with ruxolitinib. Results: We identified the IC50 values of ruxolitinib for ARH-77 and NCI-BL 2171 as 20.03 and 33.9μM at the 72nd hour, respectively. We showed that ruxolitinib induced autophagosome accumulation by 3.45 and 1.70 folds in ARH-77 and NCI-BL 2171 cells compared to the control group, respectively. Treatment with ruxolitinib decreased the expressions of IL-6, IL-18, JAK2, TYK2, and AKT genes, which play significant roles in MM pathogenesis. Conclusion: All in all, ruxolitinib is a promising agent for the regulation of the IL-6/JAK/STAT pathway and interferes with the autophagy mechanism in MM.


2008 ◽  
Vol 49 (7) ◽  
pp. 1374-1383 ◽  
Author(s):  
Antonino Neri ◽  
Sandra Marmiroli ◽  
Pierfrancesco Tassone ◽  
Luigia Lombardi ◽  
Lucia Nobili ◽  
...  

2002 ◽  
Vol 30 (3) ◽  
pp. 212-220 ◽  
Author(s):  
Yu-Tzu Tai ◽  
Klaus Podar ◽  
Stine-Kathrein Kraeft ◽  
Fengfei Wang ◽  
Gloria Young ◽  
...  

2004 ◽  
Vol 52 (5) ◽  
pp. 335-344 ◽  
Author(s):  
Naomi Gronich ◽  
Liat Drucker ◽  
Hava Shapiro ◽  
Judith Radnay ◽  
Shai Yarkoni ◽  
...  

BackgroundAccumulating reports indicate that statins widely prescribed for hypercholesteromia have antineoplastic activity. We hypothesized that because statins inhibit farnesylation of Ras that is often mutated in multiple myeloma (MM), as well as the production of interleukin (IL)-6, a key cytokine in MM, they may have antiproliferative and/or proapoptotic effects in this malignancy.MethodsU266, RPMI 8226, and ARH77 were treated with simvastatin (0-30 μM) for 5 days. The following aspects were evaluated: viability (IC50), cell cycle, cell death, cytoplasmic calcium ion levels, supernatant IL-6 levels, and tyrosine kinase activity.ResultsExposure of all cell lines to simvastatin resulted in reduced viability with IC50s of 4.5 μM for ARH77, 8 μM for RPMI 8226, and 13 μM for U266. The decreased viability is attributed to cell-cycle arrest (U266, G1; RPMI 8226, G2M) and cell death. ARH77 underwent apoptosis, whereas U266 and RPMI 8226 displayed a more necrotic form of death. Cytoplasmic calcium levels decreased significantly in all treated cell lines. IL-6 secretion from U266 cells was abrogated on treatment with simvastatin, whereas total tyrosine phosphorylation was unaffected.ConclusionsSimvastatin displays significant antimyeloma activity in vitro. Further research is warranted for elucidation of the modulated molecular pathways and clinical relevance.


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