Genome-wide studies in multiple myeloma identify XPO1/CRM1 as a critical target validated using the selective nuclear export inhibitor KPT-276
LEUKEMIA
Authors: Schmidt, J.; Braggio, E.; Kortuem, K. M.; Egan, J. B.; Zhu, Y. X.; Xin, C. S.; Tiedemann, R. E.; Palmer, S. E.; Garbitt, V. M.; McCauley, D.; Kauffman, M.; Shacham, S.; Chesi, M.; Bergsagel, P. L.; Stewart, A. K.
Abstract
RNA interference screening identified XPO1 (exportin 1) among the 55 most vulnerable targets in multiple myeloma (MM). XPO1 encodes CRM1, a nuclear export protein. XPO1 expression increases with MM disease progression. Patients with MM have a higher expression of XPO1 compared with normal plasma cells (P<0.04) and to patients with monoclonal gammopathy of undetermined significance/smoldering MM (P<0.0001). The highest XPO1 level was found in human MM cell lines (HMCLs). A selective inhibitor of nuclear export compound KPT-276 specifically and irreversibly inhibits the nuclear export function of XPO1. The viability of 12 HMCLs treated with KTP-276 was significantly reduced. KPT-276 also actively induced apoptosis in primary MM patient samples. In gene expression analyses, two genes of probable relevance were dysregulated by KPT-276: cell division cycle 25 homolog A (CDC25A) and bromodomain-containing protein 4 (BRD4), both of which are associated with c-MYC pathway. Western blotting and reverse transcription-PCR confirm that c-MYC, CDC25A and BRD4 are all downregulated after treatment with KPT-276. KPT-276 reduced monoclonal spikes in the Vk*MYC transgenic MM mouse model, and inhibited tumor growth in a xenograft MM mouse model. A phase I clinical trial of an analog of KPT-276 is ongoing in hematological malignancies including MM.
Regulatory network analysis reveals the oncogenesis roles of feed-forward loops and therapeutic target in T-cell acute lymphoblastic leukemia
BMC MEDICAL GENOMICS
Authors: Xia, Mengxuan; Zhang, Qiong; Luo, Mei; Li, Pan; Wang, Yingxue; Lei, Qian; Guo, An-Yuan
Abstract
BackgroundT-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy. Aberrant expressed genes contribute to the development and progression of T-ALL. However, the regulation underlying their aberrant expression remains elusive. Dysregulated expression of transcription factors and miRNAs played important regulatory roles in the pathogenesis of T-ALL.MethodsIn this study, we analyzed the alteration of transcriptome profiling and regulatory networks between T-ALL sample and normal T cell samples at transcriptional and post-transcriptional levels.ResultsOur results demonstrated that genes related to cell cycle and cell proliferation processes were significantly upregulated in T-ALL comparing to normal samples. Meanwhile, regulatory network analyses revealed that FOXM1, MYB, SOX4 and miR-21/19b as core regulators played vital roles in the development of T-ALL. FOXM1-miR-21-5p-CDC25A and MYB/SOX4-miR-19b-3p-RBBP8 were identified as important feed-forward loops involved in the oncogenesis of T-ALL. Drug-specific analyses showed that GSK-J4 may be an effective drug, and CDC25A/CAPN2/MCM2 could serve as potential therapeutic targets for T-ALL.ConclusionsThis study may provide novel insights for the regulatory mechanisms underlying the development of T-ALL and potential therapeutic targets.