Cancer
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12503/21648
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Browsing Cancer by Author "Chaudhary, Pankaj"
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Item Blocking LLT1-CD161 interaction enhances natural killer cell-mediated lysis of triple-negative breast cancer cells(2018-03-14) Mathew, Stephen O.; Chaudhary, Pankaj; Mathew, Porunelloor A.; Marrufo, Armando M.Purpose: Triple-negative breast cancer (TNBC) accounts for 20 percent of all breast cancer cases and is known to be the most invasive form of breast cancer. TNBC’s absence of estrogen, progesterone, and human epidermal growth factor-2 receptors makes utilizing hormonal treatments ineffective in suppressing tumor growth. TNBC is associated with poorer prognosis and higher incidences of relapse. Therefore, natural killer cell-mediated immunotherapy shows potential as a treatment option for TNBC. Natural killer cells (NK) are innate lymphoid cells that serves its role in the immune system to eradicate infected and tumor cells. NK cell function is regulated through its receptors interacting with activating and inhibitory ligands on target cells. Lectin-like Transcript-1 (LLT1, CLEC2D) is a counter-receptor that interacts with CD161 (NKRP1A) and inhibits NK cell activation. Our study demonstrated that by blocking TNBC’s LLT1 interaction with CD161 with antibodies increases lysis of TNBCs by NK cells. Methods: We have identified the expression and function of LLT1 on TNBC cell lines MDA-MB-231 and MDA-MB-436 by flow cytometry, western blot, immunofluorescent microscopy, and chromium-release assay. LLT1 expression at the cell surface was decreased through gene knockdown with small interference RNA (siRNA) transfection. Primary NK cells were isolated from peripheral blood mononuclear cells from healthy individuals and then were co-incubated with chromium-labeled TNBCs for quantification of specific lysis of TNBCs by NK cells. Results: Our results have demonstrated a higher expression of LLT1 on TNBCs than non-tumorigenic breast cell line MCF10A. We have shown that blocking LLT1 interaction with CD161 with antibodies on TNBCs have increased lysis of TNBCs by primary NK cells. We have also shown that gene knockdown of LLT1 decreases cell surface expression of LLT1 on TNBCs and increases lysis of TNBCs by NK cells. Conclusions: LLT1 expressed on TNBCs is a ligand that interacts with NK receptor CD161 and sends an inhibitory signal to the NK cell thus serving its role for TNBCs to evade immunosurveillance. Respectively, blocking LLT1 with antibodies on TNBCs and decreasing expression of LLT1 by gene knockdown increases susceptibility of TNBCs to NK cell-mediated lysis. Blocking interaction between LLT1 and CD161 with antibodies activates lysis by NK cells and will open a possible new immunotherapeutic strategy for patients diagnosed with TNBC.Item MIEN1 Regulates Breast Cancer Cell Migration and Invasion by Altering Cytoskeletal Dynamics Through Focal Adhesion Kinase and N-WASP Signaling(2018-03-14) Chaudhary, Pankaj; Kpetemey, Marilyne; Vishwanatha, Jamboor; Van Treuren, TimothyPurpose: Triple negative breast cancer (TNBC), accounts for approximately 15-20% of all breast cancer diagnoses. This is the most aggressive breast cancer subtype and is characterized by a lack of known receptors associated with, making prognosis and treatment difficult in patients with TNBC. TNBC has a propensity to metastasize to vital organs, including lung, brain and bone. This can occur early in the disease progression and usually leads to the elevated mortality rate in TNBC patients. Research efforts to identify molecular markers within TNBC for prognosis and therapy have not been fruitful. Migration and Invasion Enhancer 1 (MIEN1) has been implicated in the disease progression of many cancers, including TNBC. We determined to further understand the molecular mechanisms by which MIEN1 regulates cell motility and invasion in the context of TNBC. This knowledge will provide a basis to pursue MIEN1 as a potential marker for future treatment and evaluation of TNBC cases. Methods: Wild-type MIEN1 (MIEN1-WT) or Immunoreceptor tyrosine-based activation motif (ITAM)-mutant MIEN1 MIEN1-Y39/50F) was overexpressed in MDA-MB-231 cells to evaluate the role of ITAM signaling in MIEN1 mediated migration and invasion. Migration speed and persistence toward a chemoattractant was assessed using microfluidic chambers. Invasion was evaluated by embedding cell aggregates in a 3D collagen matrix and examining the spread of the cells. MIEN1 influence on migration was mediated by actin cytoskeletal dynamics. This mechanism was further delineated by looking at actin polymerization as well as focal adhesion adaptors and signaling molecules using western blotting as well as confocal microscopy. An in vitro kinase assay was also used to evaluate activators of MIEN1. Results: MIEN1-WT over-expression in MDA-MB-231 cells resulted increased migratory and invasive capabilities compared to wild-type cells. Additionally, over-expression of the MIEN1-Y39/50F ITAM mutant inhibited the cells’ ability to migrate towards a chemoattractant as well as invade through a collagen matrix. MIEN1 co-localized to the cell membrane with FAK (focal adhesion kinase) and facilitated signaling through N-WASP to alter cytoskeletal dynamics and increase filamentous actin accumulation. Conclusion: MIEN1 regulates migration and invasion of TNBC cells by altering cytoskeletal dynamics through activation of FAK and N-WASP, which results in increased actin polymerization and cell motility.