scholarly journals Knockdown of macrophage inhibitory cytokine-1 in RPMI-8226 human multiple myeloma cells inhibits osteoclastic differentiation through inhibiting the RANKL-Erk1/2 signaling pathway

2016 ◽  
Vol 14 (6) ◽  
pp. 5199-5204 ◽  
Author(s):  
Mingzhou Yuan ◽  
Junmin Chen ◽  
Zhiyong Zeng
Keyword(s):  
Multiple Myeloma ◽  
Signaling Pathway ◽  
Myeloma Cells ◽  
Human Multiple Myeloma ◽  
Osteoclastic Differentiation ◽  
Rpmi 8226

Reduced Response of IRE1α/Xbp-1 Signaling Pathway to Bortezomib Contributes to Drug Resistance in Multiple Myeloma Cells

2016 ◽  
Vol 103 (3) ◽  
pp. 261-267 ◽  
Author(s):  
Xiaoxuan Xu ◽  
Junru Liu ◽  
Beihui Huang ◽  
Meilan Chen ◽  
Shiwen Yuan ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Drug Resistance ◽  
Signaling Pathway ◽  
Cell Lines ◽  
Resistance Mechanism ◽  
Proteasome Inhibition ◽  
Myeloma Cells ◽  
Potential Marker ◽  
Rpmi 8226 ◽  
Basic Level

Purpose Proteasome inhibition with bortezomib eliminates multiple myeloma (MM) cells by partly disrupting unfolded protein response (UPR). However, the development of drug resistance limits its utility and resistance mechanism remains controversial. We aimed to investigate the role of IRE1α/Xbp-1 mediated branch of the UPR in bortezomib resistance. Methods The expression level of Xbp-1s was measured in 4 MM cell lines and correlated with sensitivity to bortezomib. LP1 and MY5 cells with different Xbp-1s level were treated with bortezomib; then pivotal UPR regulators were compared by immunoblotting. RPMI 8226 cells were transfected with plasmid pEX4-Xbp-1s and exposed to bortezomib; then apoptosis was determined by immunoblotting and flow cytometry. Bortezomib-resistant myeloma cells JJN3.BR were developed and the effect on UPR signaling pathway was determined. Results By analyzing 4 MM cell lines, we found little correlation between Xbp-1s basic level and bortezomib sensitivity. Bortezomib induced endoplasmic reticulum stress-initiated apoptosis via inhibiting IRE1α/Xbp-1 pathway regardless of Xbp-1s basic level. Exogenous Xbp-1s reduced cellular sensitivity to bortezomib, suggesting the change of Xbp-1s expression, not its basic level, is a potential marker of response to bortezomib in MM cells. Furthermore, sustained activation of IRE1α/Xbp-1 signaling pathway in JJN3.BR cells was identified. Conclusions Our data indicate that reduced response of IRE1α/Xbp-1 signaling pathway to bortezomib may contribute to drug resistance in myeloma cells.

scholarly journals Crispr Sgrnas Genome-Wide Screen Identifies the Proteasome Regulatory Subunit PSMC6 As a Bortezomib Resistance Gene in Human Multiple Myeloma Cells

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 450-450 ◽  
Author(s):  
Chang-Xin Shi ◽  
Klaus M Kortum ◽  
Yuan Xiao Zhu ◽  
Patrick Jedlowski ◽  
Esteban Braggio ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Next Generation Sequencing ◽  
Er Stress ◽  
Cell Line ◽  
Cell Lines ◽  
Myeloma Cells ◽  
Human Multiple Myeloma ◽  
Rpmi 8226 ◽  
Generation Sequencing ◽  
Specific Inhibitors

Abstract Background: The proteasome inhibitor Bortezomib (BTZ) is an efficient treatment option for both, newly diagnosed and relapsed/refractory multiple myeloma (MM). Despite the effectiveness, most patients eventually acquire drug resistance for reasons not fully understood Materials and methods: To better understand BTZ resistance mechanism we used a CRISPR library (GeCKO V2) targeting 19052 human genes, trying to identify genes responsible for BTZ resistance. CRISPR sgRNAs targeting the ERN1-XBP1 pathway were used as positive controls. We first infected RPMI 8226 myeloma cell line expressing Cas9 with the CRISPR library packaged into lenti-vectors and selected for resistance to BTZ. Surviving cells were subjected to next generation sequencing. Based on the initial screen results we constructed a second CRISPR sgRNA library including 31 genes, each gene targeted with four sgRNAs. After the second round screening and subsequent sequencing, we selected the top 20 genes for individual validation. Results: Proteasome regulatory gene PSMC6 was identified as the only reproducible gene conferring BTZ resistance. Interestingly, the same gene was independently found by a second group using a CRISPR approach (Sheffer M et al. ASH Abstract 273, 2014). Resistance was reproducible using a PSMC6 knockout by three individual CRISPR sgRNAs targeting exonic regions and one pair of SgRNA targeting intron region flanking exon for the deletion of exon one. PSMC6 knockout was verified by PCR and Sanger sequencing. Sensitivity to BTZ was rescued by over expression of PSMC6 cDNA in RPMI 8226 cells harboring a deletion of PSMC6 exon 1. MM cells lacking PSMC6 also developed resistance against Carfilzomib. Resistance was reproduced on a second MM cell line, KMS11. We did not see any significant difference of toxicity in PSMC6 deleted cells for other chemicals tested (tunicamycin, staurosporine, dexamethasone and melphalan). We demonstrated that the sensitivity of chymotrypsin-like activity of proteasome against BTZ was significantly reduced in cells lacking PSMC6. Consequently, MM cells without the PSMC6 gene were relatively resistant to apoptosis induced by BTZ, which was verified by Western blot for caspase 8 degradation and luminescent assay for caspase 3/7 activities. Clinically we could not correlate the PSMC6 expression level with the outcome of BTZ treatment in BTZ naive patients using publically available gene expression data. We initially used CRISPR sgRNAs targeting ER stress pathway (ERN1 and XBP1) as a positive control. However we could not derive any resistant cells from the experiment. We also could not identify any sgRNAs targeting the ERN1-XBP1 pathway from our whole exome screen and next generation sequencing. Since this contradicts published data, we decided to knockout ERN1 and XBP1 genes individually. Clones of cells with successful knockout of ERN1 in three cell lines (RPMI 8226, KMS11 and JJN3) and XBP1 in two cell lines (RPMI 8226 and KMS11) were tested for response to BTZ and Carfilzomib , however we did not find any drug response difference between the knockout and parent cells. We also found that the ERN1-XBP1 knockout cells did not show difference in response to ERN1 specific inhibitors (4u8C and STF-038010) and ER stress inducers (tunicamycin and thapsigargin) compared to parental cells. Conclusions: Human multiple myeloma cells lacking the PSMC6 gene develop significant resistance to apoptosis induced by BTZ. We have however not found a correlation of PSMC6 expression levels with outcome to BTZ treatment in BTZ naïve patients. We are therefore currently investigating the PSMC6 mutation rate in relapsed MM patients after proteasome treatment. In contrast to previous reports showing that progenitor MM cells lacing XBP-1 or ERN-1 invoked BTZ resistance, we were not able to demonstrate a change in sensitivity after full CRISPR knock out of either ERN1 or XBP1. It has long been believed that ERN1-XBP1 pathway plays an important role for MM treatment, leading to the development of ERN1 specific inhibitors. However, we demonstrated that the toxicity of two ERN1-specific inhibitors appears independent of the ERN1-XBP1 pathway. We also demonstrated that the toxicity of two important ER stress inducers, tunicamycin and thapsigargin, is independent of the ERN1-XBP1 pathway. Disclosures Stewart: Celgene: Consultancy; Oncospire Inc.: Equity Ownership; BMS: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy.

Decursin chemosensitizes human multiple myeloma cells through inhibition of STAT3 signaling pathway

2011 ◽  
Vol 301 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Hyun Jung Kim ◽  
Sung-Moo Kim ◽  
Kyung-Ran Park ◽  
Hyeung-Jin Jang ◽  
Young-Soon Na ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Signaling Pathway ◽  
Myeloma Cells ◽  
Stat3 Signaling ◽  
Stat3 Signaling Pathway ◽  
Human Multiple Myeloma

Promoting effects of MiR-135b on human multiple myeloma cells via regulation of the Wnt/β-catenin/Versican signaling pathway

Cytokine ◽  
2021 ◽  
Vol 142 ◽  
pp. 155495
Author(s):  
Hong Chen ◽  
Yuan Zhao ◽  
Jiajia Zhang ◽  
Yan Xie ◽  
Mulan Jin
Keyword(s):  
Multiple Myeloma ◽  
Signaling Pathway ◽  
Myeloma Cells ◽  
Human Multiple Myeloma

Betulinic Acid Enhances the Sensitivity of Multiple Myeloma Cells to Bortezomib by the Inactivation of the AKT/mTOR Pathway

2020 ◽  
Vol 18 (3) ◽  
pp. 241-246
Author(s):  
Yu Dan ◽  
Wan Sheng ◽  
Hu Lili
Keyword(s):  
Multiple Myeloma ◽  
Betulinic Acid ◽  
Myeloma Cell ◽  
Mtor Pathway ◽  
Prolonged Treatment ◽  
Myeloma Cells ◽  
Multiple Myeloma Cell ◽  
Increased Sensitivity ◽  
Colony Number ◽  
Rpmi 8226

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.

Phosphoproteomic analysis of primary human multiple myeloma cells

2010 ◽  
Vol 73 (7) ◽  
pp. 1381-1390 ◽  
Author(s):  
Feng Ge ◽  
Chuan-Le Xiao ◽  
Xing-Feng Yin ◽  
Chun-Hua Lu ◽  
Hui-Lan Zeng ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Myeloma Cells ◽  
Human Multiple Myeloma

β-lapachone, a novel plant product, overcomes drug resistance in human multiple myeloma cells

2002 ◽  
Vol 30 (7) ◽  
pp. 711-720 ◽  
Author(s):  
Deepak Gupta ◽  
Klaus Podar ◽  
Yu-Tzu Tai ◽  
Boris Lin ◽  
Teru Hideshima ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Drug Resistance ◽  
Myeloma Cells ◽  
Plant Product ◽  
Human Multiple Myeloma
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