Browsing by Author "Espina, Virginia"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Cell Signaling Analysis of Metastatic Triple Negative Breast Cancer Following Dual PI3K/mTOR Inhibitor (PIKTOR)Nguyen, Tuong Vi V; Nguyen, Tuong Vi V; Espina, VirginiaTriple negative breast cancer (TNBC) is defined by deficient estrogen, progesterone and HER2 receptor expression, excluding TNBC patients from effective targeted therapies for breast cancer. Advancement in targeted therapy for pro-survival pathways like PI3K/AKT/mTOR (PAM) and mitogen activated protein kinase (MAPK), has shown to improve outcomes for select TNBC patients. However, targeted therapies have not produced complete responses in the majority of patients and there is high degree of systemic relapse following conventional neoadjuvant chemotherapy, resulting in overall low therapeutic response for TNBC patients. Here we aimed to identify patterns of expression in responders vs non-responders by examining the signaling profile of metastatic (met) TNBC patients following targeted therapy against the PAM pathway. Ten patients were given an investigational oral combination of TAK-117 and TAK-228 (PIKTOR), a selective PI3Kα inhibitor and a TORC1/2 inhibitor respectively, predicted to impair DNA damage repair (DDR) pathways, increasing genomic instability and tumor sensitivity to chemotherapy. The hypothesis was successful inhibition of the PAM pathway by PIKTOR could downregulate effectors/modulator proteins of NHEJ in HRD cells. Signaling profile of pre- and post-tumor biopsy samples following PIKTOR were mapped via RPPA. Overall analysis showed heterogeneity of disease and response to treatment. The proteomic profile indicated compensatory signaling in response to treatment via upregulation of partnering MAPK pathway or upstream RTKs. Heterogenous signaling in DDR signaling pathway suggest a nonspecific stress response by TNBC tumors, unlikely to correlate DDR deficiency to patient treatment response. Pathway expression analysis of metTNBC patients at baseline and post-PIKTOR therapy highlighted key nodes in the pathway which have the potential to contribute to disease relapse. Data generated from this study could elucidate common pathway of resistance accessible for future treatments and help guide future therapeutic discoveries for advanced, metTNBC.Item Killing Pre-invasive Breast Cancer by Targeting Autophagy: A New Vision for Chemoprevention(2013-08-15) Espina, Virginia; Espina, Virginia; Liotta, Lance A.Breast cancer progression is thought to be a multi-step process involving a continuum of changes from a normal phenotype through hyperplastic lesions, carcinoma in situ, invasive carcinoma, to metastatic disease. Previously it was assumed that the invasive phenotype acquired major genetic changes during the phenotypic transition from ductal carcinoma in situ (DCIS) to invasive carcinoma. In direct contradiction to this previous assumption, herein we demonstrate the pre-existence of genetically abnormal, tumorigenic carcinoma progenitor cells within human breast DCIS lesions. Human DCIS cells were cultivated "ex vivo" without "a priori" enzymatic treatment or sorting. The DCIS organoid cultures induced the emergence of neoplastic epithelial cells exhibiting the following characteristics: a) spontaneous generation of spheroids and duct-like 3-D structures in culture within 2-4 weeks, b) tumorigenicity in NOD SCID mice, and c) "in vitro" migration and invasion of autologous breast stroma. Proteomic characterization revealed that DCIS cells up-regulate signaling pathways directly, and indirectly, linked to cellular autophagy. Cells proliferate and accumulate within the non-vascular intraductal space under hypoxic and metabolic stress. Autophagy was found to be required for survival and anchorage independent growth, in the patient's original DCIS lesion and the mouse xenograft. Molecular karyotyping demonstrated DCIS cells to be cytogenetically abnormal (copy number loss or gain in chromosomes including 1, 5, 6, 8, 13, 17) compared to the normal karyotype of the non-neoplastic cells in the patient's breast tissue. To demonstrate the dependence of the cytogenetically abnormal DCIS cells on autophagy as a survival mechanism, primary human DCIS cell cultures were treated with chloroquine phosphate, a lysosomotropic inhibitor of autophagy. Chloroquine treatment completely suppressed generation of DCIS spheroids, suppressed "ex vivo" invasion of autologous stroma, induced apoptosis, suppressed autophagy associated proteins including Atg5, AKT/PI3K, and mTOR, eliminated cytogenetically abnormal spheroid forming cells, and abrogated xenograft tumor formation. A phase I/II clinical trial (PINC; Preventing Invasive breast Neoplasia with Chloroquine) was established for evaluating safety and efficacy of chloroquine phosphate to treat breast Ductal Carcinoma in Situ. Therapy that induces regression, or prevents progression, of pre-invasive lesions could comprise a new treatment strategy for pre-invasive cancers independent of hormone receptor status.Item Reverse-Phase Microarray Analysis Reveals Novel Targets in Lymph Nodes of Bacillus anthracis Spore-Challenged Mice(Public Library of Science, 2015-06-19) Popova, Taissia G.; Espina, Virginia; Liotta, Lance; Popov, Serguei G.Anthrax is a frequently fatal infection of many animal species and men. The causative agent Bacillus anthracis propagates through the lymphatic system of the infected host; however, the specific interactions of the host and microbe within the lymphatics are incompletely understood. We report the first description of the phosphoprotein signaling in the lymph nodes of DBA/2 mice using a novel technique combining the reverse-phase microarray with the laser capture microdissesction. Mice were challenged into foot pads with spores of toxinogenic, unencapsulated Sterne strain. The spores quickly migrated to the regional popliteal lymph nodes and spread to the bloodstream as early as 3 h post challenge. All mice died before 72 h post challenge from the systemic disease accompanied by a widespread LN tissue damage by bacteria, including the hemorrhagic necrotizing lymphadenitis, infiltration of CD11b+ and CD3+ cells, and massive proliferation of bacteria in lymph nodes. A macrophage scavenger receptor CD68/macrosialin was upregulated and found in association with vegetative bacteria likely as a marker of their prior interaction with macrophages. The major signaling findings among the 65 tested proteins included the reduced MAPK signaling, upregulation of STAT transcriptional factors, and altered abundance of a number of pro- and anti-apoptotic proteins with signaling properties opposing each other. Downregulation of ERK1/2 was associated with the response of CD11b+ macrophages/dendritic cells, while upregulation of the pro-apoptotic Puma indicated a targeting of CD3+ T-cells. A robust upregulation of the anti-apoptotic survivin was unexpected because generally it is not observed in adult tissues. Taken together with the activation of STATs it may reflect a new pathogenic mechanism aimed to delay the onset of apoptosis. Our data emphasize a notion that the net biological outcome of disease is determined by a cumulative impact of factors representing the microbial insult and the protective capacity of the host.