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Anti-β₂-microglobulin monoclonal antibodies overcome bortezomib resistance in multiple myeloma by inhibiting autophagy.

Zhang M, He J, Liu Z, Lu Y, Zheng Y, Li H, Xu J, Liu H, Qian J, Orlowski RZ, Kwak LW, Yi Q, Yang J - Oncotarget (2015)

Bottom Line: Our results showed that anti-β2M mAbs enhanced BTZ-induced apoptosis of MM cell lines and primary MM cells.Combination treatment could also induce apoptosis of BTZ-resistant MM cells, and the enhanced effect depended on the surface expression of β2M on MM cells.BTZ treatment increased, whereas combination with anti-β2M mAbs reduced, NF-κB transcription activities in MM cells, and combination treatment inhibited NF-κB p65 binding to the beclin 1 promoter.

View Article: PubMed Central - PubMed

Affiliation: Department of Lymphoma/Myeloma, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.

ABSTRACT
Our previous studies showed that anti-β2M monoclonal antibodies (mAbs) have strong and direct apoptotic effects on multiple myeloma (MM) cells, suggesting that anti-β2M mAbs might be developed as a novel therapeutic agent. In this study, we investigated the anti-MM effects of combination treatment with anti-β2M mAbs and bortezomib (BTZ). Our results showed that anti-β2M mAbs enhanced BTZ-induced apoptosis of MM cell lines and primary MM cells. Combination treatment could also induce apoptosis of BTZ-resistant MM cells, and the enhanced effect depended on the surface expression of β2M on MM cells. BTZ up-regulated the expression of autophagy proteins, whereas combination with anti-β2M mAbs inhibited autophagy. Sequence analysis of the promoter region of beclin 1 identified 3 putative NF-κB-binding sites from -615 to -789 bp. BTZ treatment increased, whereas combination with anti-β2M mAbs reduced, NF-κB transcription activities in MM cells, and combination treatment inhibited NF-κB p65 binding to the beclin 1 promoter. Furthermore, anti-β2M mAbs and BTZ combination treatment had anti-MM activities in an established MM mouse model. Thus, our studies provide new insight and support for the clinical development of an anti-β2M mAb and BTZ combination treatment to overcome BTZ drug resistance and improve MM patient survival.

No MeSH data available.


Related in: MedlinePlus

Combination of anti-β2M mAbs and BTZ restores the sensitivity of BTZ-resistant MM cells to BTZ treatmentWild type (wt) or BTZ-resistant (BR) KAS-6 (A and B) and OPM-2 (C and D) cells were cultured in medium with the addition of BTZ or anti-β2M mAbs, singly or in combination, for 24 hours. MM cell apoptosis was monitored by annexin-V binding assay. The percentage of cells undergoing apoptosis increased in a dose-dependent manner in the BTZ-sensitive cells, with no change in the percentage undergoing apoptosis in BTZ-resistant KAS-6 cells (A) and OPM-2 cells (C), treated with various BTZ concentrations. Also shown is the increase in the percentage of cells undergoing apoptosis in either wild type or BTZ-resistant KAS-6 (B) and OPM-2 (D) cells, treated with the combination of BTZ (5 nM) and anti-β2M mAbs (10 μg/mL), compared with cells treated with BTZ only. Summarized data from three independent experiments are shown. **P < 0.01.
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Figure 2: Combination of anti-β2M mAbs and BTZ restores the sensitivity of BTZ-resistant MM cells to BTZ treatmentWild type (wt) or BTZ-resistant (BR) KAS-6 (A and B) and OPM-2 (C and D) cells were cultured in medium with the addition of BTZ or anti-β2M mAbs, singly or in combination, for 24 hours. MM cell apoptosis was monitored by annexin-V binding assay. The percentage of cells undergoing apoptosis increased in a dose-dependent manner in the BTZ-sensitive cells, with no change in the percentage undergoing apoptosis in BTZ-resistant KAS-6 cells (A) and OPM-2 cells (C), treated with various BTZ concentrations. Also shown is the increase in the percentage of cells undergoing apoptosis in either wild type or BTZ-resistant KAS-6 (B) and OPM-2 (D) cells, treated with the combination of BTZ (5 nM) and anti-β2M mAbs (10 μg/mL), compared with cells treated with BTZ only. Summarized data from three independent experiments are shown. **P < 0.01.

Mentions: To investigate whether combining anti-β2M mAbs and BTZ enhances the anti-MM effects of BTZ in BTZ-resistant MM cells, we used BTZ-sensitive (KAS-6.wt and OPM-2.wt) and BTZ-resistant (KAS-6.BR and OPM-2.BR) MM cells [31]. First, we confirmed cell sensitivity to BTZ treatment, observing that BTZ treatment induced apoptosis of BTZ-sensitive cells in a dose-dependent manner, but did not induce apoptosis of BTZ-resistant cells (Figure 2A and 2C; P < 0.01). Next, we analyzed apoptosis of BTZ-sensitive and BTZ-resistant MM cells treated with BTZ or anti-β2M mAbs, alone or in combination. After 24-hour treatment, BTZ was effective in BTZ-sensitive cells but not in BTZ-resistant cells, whereas combining BTZ with anti-β2M mAbs induced apoptosis in both BTZ-sensitive and BTZ-resistant cells, and was more efficacious than BTZ treatment alone (Figure 2B and 2D; P < 0.01). These results indicate that combining anti-β2M mAbs with BTZ overcomes BTZ resistance in MM.


Anti-β₂-microglobulin monoclonal antibodies overcome bortezomib resistance in multiple myeloma by inhibiting autophagy.

Zhang M, He J, Liu Z, Lu Y, Zheng Y, Li H, Xu J, Liu H, Qian J, Orlowski RZ, Kwak LW, Yi Q, Yang J - Oncotarget (2015)

Combination of anti-β2M mAbs and BTZ restores the sensitivity of BTZ-resistant MM cells to BTZ treatmentWild type (wt) or BTZ-resistant (BR) KAS-6 (A and B) and OPM-2 (C and D) cells were cultured in medium with the addition of BTZ or anti-β2M mAbs, singly or in combination, for 24 hours. MM cell apoptosis was monitored by annexin-V binding assay. The percentage of cells undergoing apoptosis increased in a dose-dependent manner in the BTZ-sensitive cells, with no change in the percentage undergoing apoptosis in BTZ-resistant KAS-6 cells (A) and OPM-2 cells (C), treated with various BTZ concentrations. Also shown is the increase in the percentage of cells undergoing apoptosis in either wild type or BTZ-resistant KAS-6 (B) and OPM-2 (D) cells, treated with the combination of BTZ (5 nM) and anti-β2M mAbs (10 μg/mL), compared with cells treated with BTZ only. Summarized data from three independent experiments are shown. **P < 0.01.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 2: Combination of anti-β2M mAbs and BTZ restores the sensitivity of BTZ-resistant MM cells to BTZ treatmentWild type (wt) or BTZ-resistant (BR) KAS-6 (A and B) and OPM-2 (C and D) cells were cultured in medium with the addition of BTZ or anti-β2M mAbs, singly or in combination, for 24 hours. MM cell apoptosis was monitored by annexin-V binding assay. The percentage of cells undergoing apoptosis increased in a dose-dependent manner in the BTZ-sensitive cells, with no change in the percentage undergoing apoptosis in BTZ-resistant KAS-6 cells (A) and OPM-2 cells (C), treated with various BTZ concentrations. Also shown is the increase in the percentage of cells undergoing apoptosis in either wild type or BTZ-resistant KAS-6 (B) and OPM-2 (D) cells, treated with the combination of BTZ (5 nM) and anti-β2M mAbs (10 μg/mL), compared with cells treated with BTZ only. Summarized data from three independent experiments are shown. **P < 0.01.
Mentions: To investigate whether combining anti-β2M mAbs and BTZ enhances the anti-MM effects of BTZ in BTZ-resistant MM cells, we used BTZ-sensitive (KAS-6.wt and OPM-2.wt) and BTZ-resistant (KAS-6.BR and OPM-2.BR) MM cells [31]. First, we confirmed cell sensitivity to BTZ treatment, observing that BTZ treatment induced apoptosis of BTZ-sensitive cells in a dose-dependent manner, but did not induce apoptosis of BTZ-resistant cells (Figure 2A and 2C; P < 0.01). Next, we analyzed apoptosis of BTZ-sensitive and BTZ-resistant MM cells treated with BTZ or anti-β2M mAbs, alone or in combination. After 24-hour treatment, BTZ was effective in BTZ-sensitive cells but not in BTZ-resistant cells, whereas combining BTZ with anti-β2M mAbs induced apoptosis in both BTZ-sensitive and BTZ-resistant cells, and was more efficacious than BTZ treatment alone (Figure 2B and 2D; P < 0.01). These results indicate that combining anti-β2M mAbs with BTZ overcomes BTZ resistance in MM.

Bottom Line: Our results showed that anti-β2M mAbs enhanced BTZ-induced apoptosis of MM cell lines and primary MM cells.Combination treatment could also induce apoptosis of BTZ-resistant MM cells, and the enhanced effect depended on the surface expression of β2M on MM cells.BTZ treatment increased, whereas combination with anti-β2M mAbs reduced, NF-κB transcription activities in MM cells, and combination treatment inhibited NF-κB p65 binding to the beclin 1 promoter.

View Article: PubMed Central - PubMed

Affiliation: Department of Lymphoma/Myeloma, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.

ABSTRACT
Our previous studies showed that anti-β2M monoclonal antibodies (mAbs) have strong and direct apoptotic effects on multiple myeloma (MM) cells, suggesting that anti-β2M mAbs might be developed as a novel therapeutic agent. In this study, we investigated the anti-MM effects of combination treatment with anti-β2M mAbs and bortezomib (BTZ). Our results showed that anti-β2M mAbs enhanced BTZ-induced apoptosis of MM cell lines and primary MM cells. Combination treatment could also induce apoptosis of BTZ-resistant MM cells, and the enhanced effect depended on the surface expression of β2M on MM cells. BTZ up-regulated the expression of autophagy proteins, whereas combination with anti-β2M mAbs inhibited autophagy. Sequence analysis of the promoter region of beclin 1 identified 3 putative NF-κB-binding sites from -615 to -789 bp. BTZ treatment increased, whereas combination with anti-β2M mAbs reduced, NF-κB transcription activities in MM cells, and combination treatment inhibited NF-κB p65 binding to the beclin 1 promoter. Furthermore, anti-β2M mAbs and BTZ combination treatment had anti-MM activities in an established MM mouse model. Thus, our studies provide new insight and support for the clinical development of an anti-β2M mAb and BTZ combination treatment to overcome BTZ drug resistance and improve MM patient survival.

No MeSH data available.


Related in: MedlinePlus