• BMB Reports
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• v.47 no.5
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• pp.274-279
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• 2014

Bortezomib has been known as the most promising anti-cancer drug for multiple myeloma (MM). However, recent studies reported that not all MM patients respond to bortezomib. To overcome such a stumbling-block, studies are needed to clarify the mechanisms of bortezomib resistance. In this study, we established a bortezomib-resistant cell line (U266/velR), and explored its biological characteristics. The U266/velR showed reduced sensitivity to bortezomib, and also showed cross-resistance to the chemically unrelated drug thalidomide. U266/velR cells had a higher proportion of CD138 negative subpopulation, known as stem-like feature, compared to parental U266 cells. U266/velR showed relatively less inhibitory effect of prosurvival NF-${\kappa}B$ signaling by bortezomib. Further analysis of RNA microarray identified genes related to ubiquitination that were differentially regulated in U266/velR. Moreover, the expression level of CD52 in U266 cells was associated with bortezomib response. Our findings provide the basis for developing therapeutic strategies in bortezomib-resistant relapsed and refractory MM patients.

• YAKHAK HOEJI
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• v.55 no.6
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• pp.466-472
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• 2011

NF-E2-related factor 2 (Nrf2), a master regulator of antioxidant genes in animals, has been associated with the resistance of cancer cells to several cytotoxic chemotherapeutics. Bortezomib, a reversible inhibitor of the 26S proteasome, is a novel class anti-cancer therapeutics approved for the treatment of refractory multiple myeloma. However, the molecular mechanism of drug-resistance remains elusive. In the present study, bortezomib sensitivity has been investigated in Nrf2 knockdown ovarian cancer cells. When Nrf2 expression is stably repressed using interfering RNA expression, bortezomib-induced apoptosis and cell death were significantly enhanced compared to nonspecific RNA control cells. Knockdown cells showed elevated expression in the catalytic subunit PSMB5, PSMB6, and PSMB7 compared to the control, and failed to induce heme oxygenase-1 expression following bortezomib treatment. These indicate that differential proteasome levels and altered expression of stress-response genes could be underlying mechanisms of bortezomib sensitization in Nrf2-inhibited ovarian cancer cells.

• Journal of the Korean Chemical Society
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• v.55 no.5
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• pp.765-775
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• 2011

Novel analogs of bortezomib were designed, synthesized and in vitro biological evaluation was carried out using human tumor cell lines A549 and PC3. Docking studies of these analogs of bortezomib was discussed. According to biological investigations, the inhibitors 4, 6, and 8 were found to be more potent than reference drug candidate bortezomib. A549 cell line showed significant sensitivity towards 4, 6, and 8 with $IC_{50}$ values 14.03, 18.5, and 12.4 nM, respectively, and PC3 cell line showed IC50 values 26.1, 37.0, and 21.2 nM, respectively. The $IC_{50}$ values of bortezomib in these cell lines are 27.3 nM and 42.0 nM.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6469-6473
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• 2013

The aim of this study was to detect the efficiency of arsenic trioxide (ATO) alone or together with bortezomib to inhibit proliferation and induce apoptosis in a multiple myeloma (MM) RPMI 8266 cells. Mechanisms of action were also investigated. RPMI 8266 cells were treated with ATO alone and in combination with bortezomib for 24 hours, and cell viability was assessed by modified MTT. Annexin V-F1TC and PI staining was used to detect the apoptosis rate and cell cycling was investigated by flow cytometry, along with expression of cell surface death receptor-4(DR4) and death receptor-5 (DR5). Western blotting was applied to detect the expression of bcl-2, caspase-3, caspase-8, and caspase-9. As a result, the ATO combined with bortezomib group showed more inhibition of RPMI 8266 cell viability than theATO group. Expression of DR4 and DR5 on the cell surfaces, and the apoptosis rate were increased after treatment by ATO alone or combined with bortezomib. The cells appeared to arrest in G2/M phase after treatment. Expression of bcl-2 was more significantly decreased in the combination group, and that of caspase-3, caspase-8 and caspase-9 was significantly increased as well. Therefore, bortezomib can enhance ATO actions to induce apoptosis in RPMI 8266 cells, with decrease in expression of bcl-2 and increase of caspase-3, caspase-8 and caspase-9 proteins.

• Korean Journal of Acupuncture
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• v.32 no.4
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• pp.208-212
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• 2015

Objectives : We present a successful administration of acupuncture in alleviating persistant peripheral neuropathy due to bortezomib, a potent therapeutic agent of mutlple myeloma. Methods : A patient, experiencing numbness, coldness, tingling and weakness in her feet and hands after bortezomib treatment, was administered acupuncture for 32 weeks, 3 times/week for first 4 weeks and 2 times/week the last 28 weeks, in bilateral acupuncture points, ST36, ST40, EX-LE10, LI11, TE5, and EX-UE9. Responses were assessed at the end of every 4 weeks with Eastern Cooperative Oncology Group(ECOG) grading system, National Cancer Institute - Common Toxicity Criteria(NCIC-CTC) v4.0, Numeric Rating Scale(NRS) 0-10, and Neuropathy Pain Scale (NPS). Results : ECOG was improved from 2 to 1, NCIC-CTC from 2 to 1, NRS from 8 to 1, and NPS from 41 to 5 through 32 weeks of acupuncture treatment. Conclusions : It is conceivable that acupuncture can be a help to relieve bortezomib induced peripheral neuropathy.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.27 no.1
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• pp.71-76
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• 2024

Recurrence of progressive familial intrahepatic cholestasis (PFIC) type II poses challenges during postoperative liver transplant care. Posttransplant patients with PFIC type II risk developing recurrent cholestasis with normal gamma-glutamyl transferase activity, which mimics the original bile salt export pump (BSEP) protein deficiency and is related to a form of immunoglobulin G antibody (anti-BSEP)-mediated rejection. Bortezomib effectively induces apoptosis of actively antibody-producing plasma cells that may have a role in antibodymediated rejection. In this case, we used bortezomib to treat PFIC type II recurrence after liver transplantation in a child.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.5
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• pp.2093-2098
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• 2015

In patients with multiple myeloma (MM), once-weekly intravenous injection or twice-weekly subcutaneous injection (SC) of bortezomib has been proven to offer non-inferior efficacy to standard twice-weekly intravenous administration, with an improved safety profile. However, whether once-weekly SC bortezomib can further reduce the incidence rate of peripheral neuropathy (PN) and not compromise the efficacy remains to be investigated. 25 patients of MM treated with once-weekly SC bortezomib were reviewed in this study. The median treatment cycles were 4 (range, 2-9 cycles). Complete response (CR) rate was 52%, ${\geq}$very good partial response (VGPR) rate was 72%, and ${\geq}$partial response (PR) rate was 84%. 1-year and 2-year PFS rate was 63.0% and 34.3%, respectively, and 2-year OS rate was 100%. Any grade of PN was reported in 9 patients (36.0%), with 7 patients (28.0%) had grade 1 PN, and 2 patients (8.0%) had grade 2 PN. No patients reported grade 3/4 PN in this cohort. In conclusion, once-weekly subcutaneous administration of bortezomib offers excellent efficacy with a further improved safety profile, especially with regard to PN. It needs to be validated in future prospective randomized trials.

• IMMUNE NETWORK
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• v.12 no.3
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• pp.126-128
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• 2012

We report on a case of severe hepatotoxicity in a 52-year-old male with multiple myeloma (MM) who had received bortezomib therapy. At patient presentation, liver enzymes were normal, but started to markedly increase 3 days after the patient's second dose of bortezomib was administered, when free kappa light chains were noticeably reduced in the serum. After discontinuation of bortezomib, liver enzymes recovered gradually to baseline. Then, the patient was started on a thalidomide-containing regimen, which he was able to tolerate well. The patient achieved complete remission prior to autologous stem cell transplantation (ASCT). The patient underwent ASCT without occurrence of further liver toxicity.

• Biomolecules & Therapeutics
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• v.32 no.1
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• pp.65-76
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• 2024

Bortezomib (BTZ) is a proteasome inhibitor used to treat multiple myeloma (MM). However, the induction of peripheral neuropathy is one of the major concerns in using BTZ to treat MM. In the current study, we have explored the effects of BTZ (0.01-5 nM) on rat neural stem cells (NSCs). BTZ (5 nM) induced cell death; however, the percentage of neurons was increased in the presence of mitogens. BTZ reduced the B-cell lymphoma 2 (Bcl-2)/Bcl-2 associated X protein ratio in proliferating NSCs and differentiated cells. Inhibition of βIII-tubulin (TUBB3) degradation was observed, but not inhibition of glial fibrillary acidic protein degradation, and a potential PEST sequence was solely found in TUBB3. In the presence of growth factors, BTZ increased cAMP response element-binding protein (CREB) phosphorylation, brain-derived neurotrophic factor (Bdnf) transcription, BDNF expression, and Tubb3 transcription in NSCs. However, in the neuroblastoma cell line, SH-SY5Y, BTZ (1-20 nM) only increased cell death without increasing CREB phosphorylation, Bdnf transcription, or TUBB3 induction. These results suggest that although BTZ induces cell death, it activates neurogenic signals and induces neurogenesis in NSCs.

• BMB Reports
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• v.48 no.10
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• pp.571-576
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• 2015

SB743921 is a potent inhibitor of the spindle protein kinesin and is being investigated in ongoing clinical trials for the treatment of myeloma. However, little is known about the molecular events underlying the induction of cell death in multiple myeloma (MM) by SB743921, alone or in combination treatment. Here, we report that SB743921 induces mitochondria-mediated cell death via inhibition of the $NF-{\kappa}B$ signaling pathway, but does not cause cell cycle arrest in KMS20 MM cells. SB743921-mediated inhibition of the $NF-{\kappa}B$ pathway results in reduced expression of SOD2 and Mcl-1, leading to mitochondrial dysfunction. We also found that combination treatment with SB743921 and bortezomib induces death in bortezomib-resistant KMS20 cells. Altogether, these data suggest that treatment with SB743921 alone or in combination with bortezomib offers excellent translational potential and promises to be a novel MM therapy.