Arsenic trioxide-mediated growth inhibition of myeloma cells is associated with an extrinsic or intrinsic signaling pathway through activation of TRAIL or TRAIL receptor 2

Abstract Abstract 4899 Arsenic trioxide (ATO) is a well-known inhibitor of cell proliferation in certain forms of malignancy and has been successfully used in the treatment of acute promyelocytic leukemia. Preclinical and clinical studies showed that ATO has anti-myeloma effects both as a single agent and in the combination therapy; however, the underlying molecular mechanism remains elusive. This study was performed to evaluate the molecular mechanism underlying its anti-myeloma activities. Cells from OPM2, U266, RPMI8226 myeloma cell lines and patients diagnosed with myeloma (n=6) were cultured with various concentrations of ATO for 4 days. Cell growth and viability were assayed by trypan blue dye exclusion. Cell cycle and apoptosis were analyzed by flow cytometry using CellQuest software and Vybrant Apoptosis Assay Kit. Alterations of the signaling pathways induced by ATO were tested by real-time PCR and western blot. ATO induced potent inhibition of myeloma cell growth compared with untreated control cells. Further investigation showed that ATO down-regulated c-Myc and phosphorylated (p)-Rb, while it up-regulated p53, p21Clip1, and p27Kip1 proteins, resulting in G2/M cell cycle arrest and cell growth inhibition. ATO treatment increased mRNA levels of interferon regulatory factor-1 (IRF-1) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), as well as protein levels of caspase 8 and cleaved caspase 3, indicating involvement of the extrinsic apoptotic pathway. No significant change was detected in the expression levels of Bax, Bcl-xL caspase 9 and Bcl-2, indicating that the intrinsic signaling pathway was not involved. A pan-caspase inhibitor abrogated ATO-induced apoptosis of myeloma cells. Our data suggest that ATO induces apoptosis in MM cells most likely through an extracellular signaling pathway. Disclosures No relevant conflicts of interest to declare.

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Combination of ATRA with a COX2 Inhibitor Induces Synergistic Effects On RARalpha2-Expressing Multiple Myeloma (MM) Cells.

Blood ◽

10.1182/blood.v114.22.2809.2809 ◽

2009 ◽

Vol 114 (22) ◽

pp. 2809-2809

Author(s):

Siqing Wang ◽

Lei Shi ◽

Hongwei Xu ◽

Chunjiao Xu ◽

Maurizio Zangari ◽

...

Keyword(s):

Colon Cancer ◽

Cell Death ◽

Growth Inhibition ◽

Wnt Signaling ◽

Signaling Pathway ◽

Wnt Signaling Pathway ◽

Erk Signaling ◽

Atra Treatment ◽

Myeloma Cells ◽

Cox 2

Abstract Abstract 2809 Poster Board II-785 We recently observed that ATRA treatment selectively kills RARalpha2-expressing, while sparing RARalpha2-deficient MM cells. Previous investigations in the colon cancer cells have shown that ATRA inhibits WNT signaling through down-regulation of COX-2. Therefore, we wanted to evaluate the role of WNT signaling in ATRA-induced cell death and growth inhibition of RARalpha2-expressing myeloma cells. To our surprise, we found that ATRA treatment activated but not inhibited WNT signaling in RARalpha2-expressing myeloma cells, based on increased β-catenin levels in ATRA-treated cells. ATRA exerted minimal effects on activation of WNT signaling pathway in RARalpha2-deficient MM cells, and forced expression of RARalpha2 in RARalpha2-deficient cells restored the stimulatory activities of ATRA on the WNT signaling pathway, demonstrating that RARalpha2 expression is required for the ATRA-induced stimulation of WNT signaling in MM cells. Lithium chloride (LiCl) treatment, which activates WNT signaling, partially abrogated ATRA-induced cell death and growth inhibition in RARalpha2-expressing cells, indicating that ATRA-induced activation of WNT signaling resulted in ATRA-resistance and decreased killing of MM cells, suggesting that a combination of targeting WNT signaling pathway and ATRA treatment is necessary for ATRA-based therapy of RARalpha2-expressing myeloma. COX-2 inhibition blocks WNT signaling in colon cancer. Similarly, we found that a COX-2 inhibitor CAY10404 also blocked WNT signaling in RARalpha2-expressing cells as well as in ATRA-treated cells. Interestingly, CAY10404 activated MEK/ERK signaling pathway, while ATRA abrogated CAY10404-induced activation of MEK/ERK signaling pathway. These results demonstrate that the combination of ATRA and COX-2 inhibitor exerts synergistic inhibitory effects on both WNT and MEK/ERK signaling pathways. A combination of ATRA and the COX-2 inhibitor resulted in synergistic cytotoxicity of RARalpha2-expressing MM cells in-vitro. More importantly, the combination of ATRA and CAY10404 also resulted in a synergistic growth inhibition of established MM tumors in SCID mice. Our study demonstrates the importance of targeting WNT signaling in ATRA-based therapy in RARalpha2-expressing myeloma and provides a rationale for the combinational use of ATRA and COX-2 inhibitors. Disclosures: No relevant conflicts of interest to declare.

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Growth Inhibition of Human Multiple Myeloma Cells by an Oncolytic Adenovirus Carrying the CD40 Ligand Transgene

Clinical Cancer Research ◽

10.1158/1078-0432.ccr-09-0451 ◽

2009 ◽

Vol 15 (15) ◽

pp. 4847-4856 ◽

Cited By ~ 21

Author(s):

Margret S. Fernandes ◽

Erica M. Gomes ◽

Lindsay D. Butcher ◽

Reuben Hernandez-Alcoceba ◽

Dongkun Chang ◽

...

Keyword(s):

Multiple Myeloma ◽

Growth Inhibition ◽

Cd40 Ligand ◽

Oncolytic Adenovirus ◽

Myeloma Cells ◽

Human Multiple Myeloma

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Sulforaphane synergistically enhances the cytotoxicity of arsenic trioxide in multiple myeloma cells via stress-mediated pathways

Oncology Reports ◽

10.3892/or.2012.1977 ◽

2012 ◽

Vol 28 (5) ◽

pp. 1851-1858 ◽

Cited By ~ 23

Author(s):

NICOLE A. DOUDICAN ◽

SHIH YA WEN ◽

AMITABHA MAZUMDER ◽

SETH J. ORLOW

Keyword(s):

Multiple Myeloma ◽

Arsenic Trioxide ◽

Myeloma Cells

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Akt Inhibition Enhanced the Growth Inhibition Effects of Low-Dose Heavy-Ion Radiation via the PI3K/Akt/p53 Signaling Pathway in C6 Glioblastoma Cells

Frontiers in Oncology ◽

10.3389/fonc.2021.649176 ◽

2021 ◽

Vol 11 ◽

Author(s):

Ke Huang ◽

Wei Zhao ◽

Xuqiao Wang ◽

Yingfei Qiu ◽

Zelin Liu ◽

...

Keyword(s):

Growth Inhibition ◽

Signaling Pathway ◽

Low Dose ◽

Ion Irradiation ◽

Heavy Ion ◽

C6 Cells ◽

Carbon Ion ◽

P53 Signaling ◽

Heavy Ion Radiation ◽

P53 Signaling Pathway

BackgroundGlioma has one of the highest mortality rates of all tumors of the nervous system and commonly used treatments almost always fail to achieve tumor control. Low-dose carbon-ion radiation can effectively target cancer and tumor cells, but the mechanisms of growth inhibition induced by heavy-ion radiation via the PI3K/Akt signaling pathway are unknown, and inhibition by heavy-ion radiation is minor in C6 cells.MethodsCarbon-ion radiation was used to investigate the effects of heavy-ion radiation on C6 cells, and suppression of Akt was performed using perifosine. MTT assays were used to investigate optimal perifosine treatment concentrations. Clone formation assays were used to investigate the growth inhibition effects of carbon-ion radiation and the effects of radiation with Akt inhibition. Lactate dehydrogenase release, superoxide dismutase activity, and malondialdehyde content were assessed to investigate oxidative stress levels. Expression levels of proteins in the PI3K/Akt/p53 signaling pathway were assessed via western blotting.ResultsThe 10% maximum inhibitory concentration of perifosine was 19.95 μM. In clone formation assays there was no significant inhibition of cell growth after treatment with heavy-ion irradiation, whereas perifosine enhanced inhibition. Heavy-ion radiation induced lactate dehydrogenase release, increased the level of malondialdehyde, and reduced superoxide dismutase activity. Akt inhibition promoted these processes. Heavy-ion radiation treatment downregulated Akt expression, and upregulated B-cell lymphoma-2 (Bcl-2) expression. p53 and Bcl-2 expression were significantly upregulated, and Bcl-2-associated X protein (Bax) expression was downregulated. The expression profiles of pAkt, Bcl-2, and Bax were reversed by perifosine treatment. Caspase 3 expression was upregulated in all radiation groups.ConclusionsThe growth inhibition effects of low-dose heavy-ion irradiation were not substantial in C6 cells, and Akt inhibition induced by perifosine enhanced the growth inhibition effects via proliferation inhibition, apoptosis, and oxidative stress. Akt inhibition enhanced the effects of heavy-ion radiation, and the PI3K/Akt/p53 signaling pathway may be a critical component involved in the process.

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Silybin suppresses cell proliferation and induces apoptosis of multiple myeloma cells via the PI3K/Akt/mTOR signaling pathway

Molecular Medicine Reports ◽

10.3892/mmr.2016.4887 ◽

2016 ◽

Vol 13 (4) ◽

pp. 3243-3248 ◽

Cited By ~ 20

Author(s):

NAN FENG ◽

JIANMIN LUO ◽

XIMIN GUO

Keyword(s):

Multiple Myeloma ◽

Cell Proliferation ◽

Signaling Pathway ◽

Mtor Signaling ◽

Mtor Signaling Pathway ◽

Myeloma Cells

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Enforced CD19 Expression Leads to Growth Inhibition and Reduced Tumorigenicity

Blood ◽

10.1182/blood.v94.10.3551.422k08_3551_3558 ◽

1999 ◽

Vol 94 (10) ◽

pp. 3551-3558 ◽

Cited By ~ 33

Author(s):

Maged S. Mahmoud ◽

Ryuichi Fujii ◽

Hideaki Ishikawa ◽

Michio M. Kawano

Keyword(s):

Growth Inhibition ◽

Cell Line ◽

Myeloma Cell ◽

Inhibitory Effect ◽

Myeloma Cell Line ◽

Growth Inhibitory Effect ◽

Myeloma Cells ◽

Growth Inhibitory ◽

Human Myeloma Cell Line

In multiple myeloma (MM), the cell surface protein, CD19, is specifically lost while it continues to be expressed on normal plasma cells. To examine the biological significance of loss of CD19 in human myeloma, we have generated CD19 transfectants of a tumorigenic human myeloma cell line (KMS-5). The CD19 transfectants showed slower growth rate in vitro than that of control transfectants. They also showed a lower capability for colony formation as evaluated by anchorage-independent growth in soft agar assay. The CD19 transfectants also had reduced tumorigenicity in vivo when subcutaneously implanted into severe combined immunodeficiency (SCID)-human interleukin-6 (hIL-6) transgenic mice. The growth-inhibitory effect was CD19-specific and probably due to CD19 signaling because this effect was not observed in cells transfected with a truncated form of CD19 that lacks the cytoplasmic signaling domain. The in vitro growth-inhibitory effect was confirmed in a nontumorigenic human myeloma cell line (U-266). However, introduction of the CD19 gene into a human erythroleukemia cell line (K-562) also induced growth inhibition, suggesting that this effect is CD19-specific, but not restricted to myeloma cells. These data suggest that the specific and generalized loss of CD19 in human myeloma cells could be an important factor contributing to the proliferation of the malignant plasma cell clones in this disease.

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

Tumori Journal ◽

10.5301/tj.5000554 ◽

2016 ◽

Vol 103 (3) ◽

pp. 261-267 ◽

Cited By ~ 4

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.

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