Clarifying the molecular mechanism of tomentosin‑induced antiproliferative and proapoptotic effects in human multiple myeloma via gene expression profile and genetic interaction network analysis

Abstract

Multiple myeloma (MM) is an aggressive B cell malignancy. Substantial progress has been made in the therapeutic context for patients with MM, however it still represents an incurable disease due to drug resistance and recurrence. development of more effective or synergistic therapeutic approaches undoubtedly represents an unmet clinical need. Tomentosin is a bioactive natural sesquiterpene lactone extracted by various plants with therapeutic properties, including anti-neoplastic effects. In the present study, the potential antitumor activity of tomentosin was evaluated on the human RPMI-8226 cell line, treated with increasing tomentosin concentration for cytotoxicity screening. The data suggested that both cell cycle arrest and cell apoptosis could explain the antiproliferative effects of tomentosin and may result in the inhibition of RPMI-8226 cell viability. To assess differentially expressed genes contributing to tomentosin activity and identify its mechanism of action, a microarray gene expression profile was performed, identifying 126 genes deregulated by tomentosin. To address the systems biology and identify how tomentosin deregulates gene expression in MM from a systems perspective, all deregulated genes were submitted to enrichment and molecular network analysis. The Protein-Protein Interaction (PPI) network analysis showed that tomentosin in human MM induced the downregulation of genes involved in several pathways known to lead immune-system processes, such as cytokine-cytokine receptor interaction, chemokine or NF-κB signaling pathway, as well as genes involved in pathways playing a central role in cellular neoplastic processes, such as growth, proliferation, migration, invasion and apoptosis. Tomentosin also induced endoplasmic reticulum stress via upregulation of cyclic AMP-dependent transcription factor ATF-4 and dNA damage-inducible transcript 3 protein genes, suggesting that in the presence of tomentosin the protective unfolded protein response signaling may induce cell apoptosis. The functional connections analysis executed using the connectivity Map tool, suggested that the effects of tomentosin on RPMI-8226 cells might be similar to those exerted by heat shock proteins inhibitors. Taken together, these data suggested that tomentosin may be a potential drug candidate for the treatment of MM.

Antineoplastic Properties by Proapoptotic Mechanisms Induction of Inula viscosa and Its Sesquiterpene Lactones Tomentosin and Inuviscolide

“…Recently, the antineoplastic activity of SLs has also been evaluated in hematologic tumors such as LB, multiple myeloma (MM), and leukemia cancer cell lines. Virdis et al demonstrated that tomentosin exerts strong antitumor activity on human BL (Raji cell line; [ 52 ]) and MM (RPMI 8226 cell line; [ 53 ]), mediated by inhibition of cell proliferation and induction of apoptosis. Apoptosis was induced by activating both the death receptor and mitochondrial pathways in Raji cells.…”

“…Furthermore, tomentosin causes endoplasmic reticulum stress via upregulation of the ATF4 and DDIT3 genes, suggesting that tomentosin treatment the activation of the protective unfolded protein response signaling might induce cell apoptosis. Functional connection analysis executed by the connectivity map tool indicated that tomentosin acts as the heat shock protein inhibitors on MM cells [ 53 ].…”