Loss of function of DOCK4 in myelodysplastic syndromes stem cells is restored by inhibitors of DOCK4 signaling networks

Sriram Sundaravel, Wen Liang Kuo, Jong Jin Jeong, Gaurav S. Choudhary, Shanisha Gordon-Mitchell, Hui Liu, Tushar D. Bhagat, Kathy L. McGraw, Sandeep Gurbuxani, Alan F. List, Amit Verma, Amittha Wickrema

Research output: Contribution to journalArticle

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Abstract

Purpose: Myelodysplastic syndromes (MDS) with deletion of chromosome 7q/7 [-7/(del)7q MDS] is associated with worse outcomes and needs novel insights into pathogenesis. Reduced expression of signaling protein dedicator of cytokinesis 4 (DOCK4) in patients with -7/(del)7q MDS leads to a block in hematopoietic stem cell (HSC) differentiation. Identification of targetable signaling networks downstream of DOCK4 will provide means to restore hematopoietic differentiation in MDS. Experimental Design: We utilized phosphoproteomics approaches to identify signaling proteins perturbed as a result of reduced expression of DOCK4 in human HSCs and tested their functional significance in primary model systems. Results: We demonstrate that reduced levels of DOCK4 lead to increased global tyrosine phosphorylation of proteins in primary human HSCs. LYN kinase and phosphatases INPP5D (SHIP1) and PTPN6 (SHP1) displayed greatest levels of tyrosine phosphorylation when DOCK4 expression levels were reduced using DOCK4-specific siRNA. Our data also found that increased phosphorylation of SHIP1 and SHP1 phosphatases were due to LYN kinase targeting these phosphatases as substrates. Increased migration and impediment of HSC differentiation were consequences of these signaling alterations. Pharmacologic inhibition of SHP1 reversed these functional aberrations in HSCs expressing low DOCK4 levels. In addition, differentiation block seen in DOCK4 haplo-insufficient [-7/(del)7q] MDS was rescued by inhibition of SHP1 phosphatase. Conclusions: LYN kinase and phosphatases SHP1 and SHIP1 are perturbed when DOCK4 expression levels are low. Inhibition of SHP1 promotes erythroid differentiation in healthy HSCs and in -7/(del)7q MDS samples with low DOCK4 expression. Inhibitors of LYN, SHP1 and SHIP1 also abrogated increased migratory properties inHSCs expressing reduced levels of DOCK4.

Original languageEnglish (US)
Pages (from-to)5638-5649
Number of pages12
JournalClinical Cancer Research
Volume25
Issue number18
DOIs
StatePublished - Sep 15 2019

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Cytokinesis
Myelodysplastic Syndromes
Stem Cells
Non-Receptor Type 6 Protein Tyrosine Phosphatase
Phosphotransferases
Phosphorylation
Hematopoietic Stem Cells
Phosphoric Monoester Hydrolases
Tyrosine
Cell Differentiation
Proteins
Chromosomes, Human, Pair 7
Small Interfering RNA
Research Design

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

Cite this

Sundaravel, S., Kuo, W. L., Jeong, J. J., Choudhary, G. S., Gordon-Mitchell, S., Liu, H., ... Wickrema, A. (2019). Loss of function of DOCK4 in myelodysplastic syndromes stem cells is restored by inhibitors of DOCK4 signaling networks. Clinical Cancer Research, 25(18), 5638-5649. https://doi.org/10.1158/1078-0432.CCR-19-0924

Loss of function of DOCK4 in myelodysplastic syndromes stem cells is restored by inhibitors of DOCK4 signaling networks. / Sundaravel, Sriram; Kuo, Wen Liang; Jeong, Jong Jin; Choudhary, Gaurav S.; Gordon-Mitchell, Shanisha; Liu, Hui; Bhagat, Tushar D.; McGraw, Kathy L.; Gurbuxani, Sandeep; List, Alan F.; Verma, Amit; Wickrema, Amittha.

In: Clinical Cancer Research, Vol. 25, No. 18, 15.09.2019, p. 5638-5649.

Research output: Contribution to journalArticle

Sundaravel, S, Kuo, WL, Jeong, JJ, Choudhary, GS, Gordon-Mitchell, S, Liu, H, Bhagat, TD, McGraw, KL, Gurbuxani, S, List, AF, Verma, A & Wickrema, A 2019, 'Loss of function of DOCK4 in myelodysplastic syndromes stem cells is restored by inhibitors of DOCK4 signaling networks', Clinical Cancer Research, vol. 25, no. 18, pp. 5638-5649. https://doi.org/10.1158/1078-0432.CCR-19-0924
Sundaravel, Sriram ; Kuo, Wen Liang ; Jeong, Jong Jin ; Choudhary, Gaurav S. ; Gordon-Mitchell, Shanisha ; Liu, Hui ; Bhagat, Tushar D. ; McGraw, Kathy L. ; Gurbuxani, Sandeep ; List, Alan F. ; Verma, Amit ; Wickrema, Amittha. / Loss of function of DOCK4 in myelodysplastic syndromes stem cells is restored by inhibitors of DOCK4 signaling networks. In: Clinical Cancer Research. 2019 ; Vol. 25, No. 18. pp. 5638-5649.
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abstract = "Purpose: Myelodysplastic syndromes (MDS) with deletion of chromosome 7q/7 [-7/(del)7q MDS] is associated with worse outcomes and needs novel insights into pathogenesis. Reduced expression of signaling protein dedicator of cytokinesis 4 (DOCK4) in patients with -7/(del)7q MDS leads to a block in hematopoietic stem cell (HSC) differentiation. Identification of targetable signaling networks downstream of DOCK4 will provide means to restore hematopoietic differentiation in MDS. Experimental Design: We utilized phosphoproteomics approaches to identify signaling proteins perturbed as a result of reduced expression of DOCK4 in human HSCs and tested their functional significance in primary model systems. Results: We demonstrate that reduced levels of DOCK4 lead to increased global tyrosine phosphorylation of proteins in primary human HSCs. LYN kinase and phosphatases INPP5D (SHIP1) and PTPN6 (SHP1) displayed greatest levels of tyrosine phosphorylation when DOCK4 expression levels were reduced using DOCK4-specific siRNA. Our data also found that increased phosphorylation of SHIP1 and SHP1 phosphatases were due to LYN kinase targeting these phosphatases as substrates. Increased migration and impediment of HSC differentiation were consequences of these signaling alterations. Pharmacologic inhibition of SHP1 reversed these functional aberrations in HSCs expressing low DOCK4 levels. In addition, differentiation block seen in DOCK4 haplo-insufficient [-7/(del)7q] MDS was rescued by inhibition of SHP1 phosphatase. Conclusions: LYN kinase and phosphatases SHP1 and SHIP1 are perturbed when DOCK4 expression levels are low. Inhibition of SHP1 promotes erythroid differentiation in healthy HSCs and in -7/(del)7q MDS samples with low DOCK4 expression. Inhibitors of LYN, SHP1 and SHIP1 also abrogated increased migratory properties inHSCs expressing reduced levels of DOCK4.",
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T1 - Loss of function of DOCK4 in myelodysplastic syndromes stem cells is restored by inhibitors of DOCK4 signaling networks

AU - Sundaravel, Sriram

AU - Kuo, Wen Liang

AU - Jeong, Jong Jin

AU - Choudhary, Gaurav S.

AU - Gordon-Mitchell, Shanisha

AU - Liu, Hui

AU - Bhagat, Tushar D.

AU - McGraw, Kathy L.

AU - Gurbuxani, Sandeep

AU - List, Alan F.

AU - Verma, Amit

AU - Wickrema, Amittha

PY - 2019/9/15

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N2 - Purpose: Myelodysplastic syndromes (MDS) with deletion of chromosome 7q/7 [-7/(del)7q MDS] is associated with worse outcomes and needs novel insights into pathogenesis. Reduced expression of signaling protein dedicator of cytokinesis 4 (DOCK4) in patients with -7/(del)7q MDS leads to a block in hematopoietic stem cell (HSC) differentiation. Identification of targetable signaling networks downstream of DOCK4 will provide means to restore hematopoietic differentiation in MDS. Experimental Design: We utilized phosphoproteomics approaches to identify signaling proteins perturbed as a result of reduced expression of DOCK4 in human HSCs and tested their functional significance in primary model systems. Results: We demonstrate that reduced levels of DOCK4 lead to increased global tyrosine phosphorylation of proteins in primary human HSCs. LYN kinase and phosphatases INPP5D (SHIP1) and PTPN6 (SHP1) displayed greatest levels of tyrosine phosphorylation when DOCK4 expression levels were reduced using DOCK4-specific siRNA. Our data also found that increased phosphorylation of SHIP1 and SHP1 phosphatases were due to LYN kinase targeting these phosphatases as substrates. Increased migration and impediment of HSC differentiation were consequences of these signaling alterations. Pharmacologic inhibition of SHP1 reversed these functional aberrations in HSCs expressing low DOCK4 levels. In addition, differentiation block seen in DOCK4 haplo-insufficient [-7/(del)7q] MDS was rescued by inhibition of SHP1 phosphatase. Conclusions: LYN kinase and phosphatases SHP1 and SHIP1 are perturbed when DOCK4 expression levels are low. Inhibition of SHP1 promotes erythroid differentiation in healthy HSCs and in -7/(del)7q MDS samples with low DOCK4 expression. Inhibitors of LYN, SHP1 and SHIP1 also abrogated increased migratory properties inHSCs expressing reduced levels of DOCK4.

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