Dataset Information

The helicase HAGE prevents interferon-?-induced PML expression in ABCB5+ malignant melanoma-initiating cells by promoting the expression of SOCS1.

ABSTRACT: The tumour suppressor PML (promyelocytic leukaemia protein) regulates several cellular pathways involving cell growth, apoptosis, differentiation and senescence. PML also has an important role in the regulation of stem cell proliferation and differentiation. Here, we show the involvement of the helicase HAGE in the transcriptional repression of PML expression in ABCB5+ malignant melanoma-initiating cells (ABCB5+ MMICs), a population of cancer stem cells which are responsible for melanoma growth, progression and resistance to drug-based therapy. HAGE prevents PML gene expression by inhibiting the activation of the JAK-STAT (janus kinase-signal transducers and activators of transcription) pathway in a mechanism which implicates the suppressor of cytokine signalling 1 (SOCS1). Knockdown of HAGE led to a significant decrease in SOCS1 protein expression, activation of the JAK-STAT signalling cascade and a consequent increase of PML expression. To confirm that the reduction in SOCS1 expression was dependent on the HAGE helicase activity, we showed that SOCS1, effectively silenced by small interfering RNA, could be rescued by re-introduction of HAGE into cells lacking HAGE. Furthermore, we provide a mechanism by which HAGE promotes SOCS1 mRNA unwinding and protein expression in vitro. Finally, using a stem cell proliferation assay and tumour xenotransplantation assay in non-obese diabetic/severe combined immunodeficiency mice, we show that HAGE promotes MMICs-dependent tumour initiation and tumour growth by preventing the anti-proliferative effects of interferon-? (IFN?). Our results suggest that the helicase HAGE has a key role in the resistance of ABCB5+ MMICs to IFN? treatment and that cancer therapies targeting HAGE may have broad implications for the treatment of malignant melanoma.

SUBMITTER: Mathieu MG

PROVIDER: S-EPMC3944245 | biostudies-literature | 2014 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The helicase HAGE prevents interferon-α-induced PML expression in ABCB5+ malignant melanoma-initiating cells by promoting the expression of SOCS1.

Mathieu M G MG Miles A K AK Ahmad M M Buczek M E ME Pockley A G AG Rees R C RC Regad T T

Cell death & disease 20140213

The tumour suppressor PML (promyelocytic leukaemia protein) regulates several cellular pathways involving cell growth, apoptosis, differentiation and senescence. PML also has an important role in the regulation of stem cell proliferation and differentiation. Here, we show the involvement of the helicase HAGE in the transcriptional repression of PML expression in ABCB5+ malignant melanoma-initiating cells (ABCB5+ MMICs), a population of cancer stem cells which are responsible for melanoma growth, ...[more]

PMID: 24525737

Similar Datasets

Project description:Interferon-alpha (pegylated interferon and ribavirin) is used as standard-of-care therapeutic for chronic hepatitis C virus infection. Besides good cure in some patients other patients do not benefit from the treatment dependent on the virus type and host factors. One class of putative effector proteins is the family of Suppressors of cytokine signalling (SOCS). They act in a classical negative feedback-loop against the action of interferons and many other cytokines. It has been proven that some of them, in particular SOCS1 and SOCS3, inhibit the expression of interferon induced antiviral proteins. Their mode of action depends on the signal they are interfering with. In relation to the interferon-gamma pathway, they are thought to act on the interferon-alpha receptors by masking its recognition site for the Janus kinases (JAK), by blocking the kinase activity of the JAKs and coincidentally hindering STAT molecules from binding to the kinases. They are also thought to ubiquitinate the JAKs resulting in their proteosomal degradation. The function of SOCS proteins in suppressing the interferon-alpha pathway has not yet been characterized exhaustively. This study should unveil links to understand the resistance in interferon-alpha therapy. As results we got almost complete silencing of JAK-STAT signaling in SOCS1 over-expressing cells and tissue-dependent partially suppressed gene induction in SOCS3 over-expressing cell lines. Two human cancer cell lines (ME-15, HuH-7) were stably transfected with pcDNA3.1-SOCS plasmids in presence of geneticin and daughter cell lines were generated after singularization of cells. Next, original cell lines as well as SOCS1 and SOCS3 over-expressing cell lines were treated with 1000 U/ml interferon-alpha for 4 or 24 hours or in normal culture medium. Cells lines obtained from SOCS4 plasmid transfections were screened as additional control. Gene expression levels of cell cultured in control (0 for 4 hours, 2 for 24 hours) or interferon-alpha supplemented medium for 4 hours (1) or 24 hours (4) were analyzed. mRNA abundance was measured in triplicates using 12x8-sample commercial Illumina microarrays (HumanRef 8, version 3) and scanner system (iScan) as well as reagents recommend by Illumina (Illumina® TotalPrep Kit).

Dataset Information

The helicase HAGE prevents interferon-?-induced PML expression in ABCB5+ malignant melanoma-initiating cells by promoting the expression of SOCS1.

Publications

The helicase HAGE prevents interferon-α-induced PML expression in ABCB5+ malignant melanoma-initiating cells by promoting the expression of SOCS1.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets