Katya Chumakova

Publications (2)12.3 Total impact

• Source

  Available from: spandidos-publications.com

  Article: Functional domains of CCN1 (Cyr61) regulate breast cancer progression.

  James O'Kelly, Alice Chung, Nathan Lemp, Katya Chumakova, Dong Yin, He-Jing Wang, Jonathan Said, Dorina Gui, Carl W Miller, Beth Y Karlan, H Phillip Koeffler
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  ABSTRACT: CCN1 plays diverse roles in cellular proliferation, survival, migration and angiogenesis. We determined the relationship between CCN1 protein expression and clinical factors that are important for the classification of breast cancer. CCN1 contains four functional domains; the contribution of each of the structural domains to the biological properties of CCN1 in breast cancer was investigated. We performed immunohistochemistry for CCN1 on a breast cancer tissue array, and conducted a detailed statistical analysis on the relationship between CCN1 protein expression and clinical factors that are important for the classification of breast cancer. The structure-function relationship was examined using four mutant constructs in which one of the modules (DM1-DM4) had been deleted. MCF-7 breast cancer cells were stably transfected with these constructs and their biological activity was tested in comparison to full-length CCN1. Staining of CCN1 in tumors was positively correlated with AJCC disease stage. A strong association also was found between lymph node involvement and high CCN1 expression in patients with invasive breast cancer; there was a significant increase in the breast cancer expression of CCN1 in patients with positive lymph nodes (P=0.004), and the levels of CCN1 correlated with the number of positive lymph nodes (P=0.0006). Deletion of module 4 rendered CCN1 unable to either bind heparin or associate with the extracellular matrix. Furthermore, MCF-7/DM4 cells demonstrated reduced cell spreading, migration and proliferation, indicating that module 4 of the protein is important for its ability to promote these activities. These findings indicate that CCN1 is involved throughout the clinical progression of breast cancer to an invasive phenotype. The multimodular structure of CCN1 enables it to fulfill multiple functions that may contribute to the different stages of cancer development, raising the prospect that specific regions of CCN1 could be targeted for therapeutic benefit to inhibit particular aspects of malignancy in breast cancer.
  International Journal of Oncology 08/2008; 33(1):59-67. · 2.40 Impact Factor
• Article: Adaptor protein Lnk negatively regulates the mutant MPL, MPLW515L associated with myeloproliferative disorders.

  Sigal Gery, Saskia Gueller, Katya Chumakova, Norihiko Kawamata, Liqin Liu, H Phillip Koeffler
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  ABSTRACT: Recently, activating myeloproliferative leukemia virus oncogene (MPL) mutations, MPLW515L/K, were described in myeloproliferative disorder (MPD) patients. MPLW515L leads to activation of downstream signaling pathways and cytokine-independent proliferation in hematopoietic cells. The adaptor protein Lnk is a negative regulator of several cytokine receptors, including MPL. We show that overexpression of Lnk in Ba/F3-MPLW515L cells inhibits cytokine-independent growth, while suppression of Lnk in UT7-MPLW515L cells enhances proliferation. Lnk blocks the activation of Jak2, Stat3, Erk, and Akt in these cells. Furthermore, MPLW515L-expressing cells are more susceptible to Lnk inhibitory functions than their MPL wild-type (MPLWT)-expressing counterparts. Lnk associates with activated MPLWT and MPLW515L and colocalizes with the receptors at the plasma membrane. The SH2 domain of Lnk is essential for its binding and for its down-regulation of MPLWT and MPLW515L. Lnk itself is tyrosine-phosphorylated following thrombopoietin stimulation. Further elucidating the cellular pathways that attenuate MPLW515L will provide insight into the pathogenesis of MPD and could help develop specific therapeutic approaches.
  Blood 12/2007; 110(9):3360-4. · 9.90 Impact Factor