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Cancer stem cells (CSC) are rare, inherently chemoresistant cells, which have the capacity to differentiate and generate the numerous cancer cell types observed in a tumor. CSC are hypothesized to be the primary source of cancer recurrence and ultimately a patient's demise. The primary objective of my laboratory is to understand cellular interactions in the tumor vascular/cancer stem cell niche with the goal of developing novel therapeutics targeting CSC proliferation and differentiation. In order to characterize these interactions, we have performed an extensive characterization of ovarian CSC and have begun to define a differentiation hierarchy of the ovarian CSC. In addition, we have characterized several components of the ovarian CSC niche; we have extensively characterized the ovarian tumor vasculature, tumor vascular associated leukocytes, and cancer associated mesenchymal stem cells. We have developed novel in vitro microfluidics devices as a means to study symmetric versus asymmetric divisions of CSC, and novel human in vivo tumor models for the study of ovarian CSC growth and differentiation. Finally, we have developed tumor vascular niche targeted nanoparticle platform with which to assess the efficacy of CSC targeted therapies delivered specifically to CSC. We are now perfectly placed to significantly develop the field of cancer stem cell based differentiation targeted therapies.
Lung cancer is the leading cause of cancer death in the United States and worldwide. Recent advances in the treatment of non-small cell lung carcinoma (NSCLC) have come from recognition that NSCLC is not a single disease entity, but rather a collection of distinct molecularly driven neoplasms. This paradigm is typified by the recent progress made in the treatment of patients with EGFR-mutant and EML4-ALK translocation-driven adenocarcinomas of the lung with tyrosine kinase inhibitors targeting these oncogenes. Unfortunately, little progress has been made in the treatment of patients with the most frequently observed driver oncogene, mutant KRAS. KRAS is mutated in approximately 25% of all NSCLC, and patients with this mutation have an increased risk of recurrence in early stage disease and have a worse prognosis with metastatic disease. My research and clinical interests revolve around the development of targeted therapies for KRAS-mutant NSCLC as well as novel strategies to overcome resistance to targeted therapies for EGFR-mutant and MET-altered NSCLC. The first line of research in my laboratory focuses on the role of the epithelial'mesenchymal transition transcription factor TWIST1 in oncogene-driven NSCLC. We have demonstrated the TWIST1 is essential for lung tumorigenesis for several key oncogenic drivers including KRAS mutant, EGFR mutant and MET mutant/amplified NSCLC. Furthermore, we have demonstrated that TWIST1 overexpression leads to resistance to EGFR and MET targeted therapies. We are currently examining the mechanism(s) through which this occurs and developing therapeutic combinations to overcome this resistance. Furthermore, we are exploring whether targeting the HGF-MET-TWIST1 pathway can be an effective strategy for preventing or treating lung brain metastases. Importantly, we have developed a novel TWIST1 inhibitor which serves a tool compound for our therapeutic studies and serves as the basis for our current drug screening efforts in order to develop a TWIST1 inhibitor that we can translate to the clinic. The second line of research in my lab focuses on studying the mechanisms of resistance to the Hsp90 inhibitor, ganetespib in KRAS-mutant NSCLC so that we can use to develop a rationally designed Hsp90 inhibitor combination for the clinic which can prevent or overcome resistance. Of note, we have recently demonstrated that the ERK-p90RSK-CDC25C pathway plays a key role in resistance to Hsp90 inhibitors through bypass of a G2/M checkpoint. These data suggest that the combination of an ERK inhibitor with an Hsp90 inhibitor maybe effective in KRAS mutant NSCLC and we hope to test this combination in early phase trials soon.
Most cells can not divide indefinitely due to a process termed cellular senescence. Because cancer cells need to escape cellular senescence in order to proliferate and eventually form tumors, it is well accepted that cellular senescence is a powerful tumor suppressive mechanism. In addition, since several molecular changes that are observed in senescent cells occur in somatic cells during the aging process, investigating the molecular mechanisms underlying cellular senescence will also allow us to better understand the more complicated aging process. Thus, molecules that regulate cellular senescence represent potential therapeutic targets for the prevention and treatment of cancer as well as the fight against aging. Our work is directed at unraveling the role of caveolin-1 as a novel mediator of cellular senescence. Caveolin-1 is the structural protein component of caveolae, invaginations of the plasma membrane involved in signal transduction. Caveolin-1 acts as a scaffolding protein to concentrate, organize, and functionally modulate signaling molecules within caveolar membranes. Our laboratory was the first to demonstrate that caveolin-1 plays a pivotal role in oxidative stress-induced premature senescence. We found that oxidative stress upregulates caveolin-1 protein expression through the p38 MAPK/Sp1-mediated activation of the caveolin-1 gene promoter. We also demonstrated that upregulation of caveolin-1 protein expression promotes premature senescence through activation of the p53/p21Waf1/Cip1 pathway by acting as a regulator of Mdm2, PP2A-C, TrxR1 and Nrf2. Moreover, we found that caveolin-1-mediated premature senescence regulates cell transformation and contributes to cigarette smoke-induced pulmonary emphysema, directly linking caveolin-1's function to age-related diseases. Taken together, our findings indicate that caveolin-1 plays a central role in the signaling events that lead to cellular senescence. Our current main research interest is the identification, at the molecular level, of novel signaling pathways that link caveolin-1 to oxidative stress-induced premature senescence and the characterization of their relevance to aging and age-related diseases using both cellular and animal models. These investigations will provide novel insights into the cellular and molecular mechanisms underlying aging and cancerous cell transformation and will identify novel molecular targets that can be exploited for the development of alternative therapeutic options in the context of age-related diseases, including cancer.
The goal of the Lee laboratory is translational breast cancer research. The laboratory has two main areas of focus. The first involves targeting the insulin-like growth factor pathway in breast cancer. A major emphasis is upon the downstream signaling intermediates the insulin receptor substrates (IRSs) analyzing interactions with steroid hormone receptors (ER and PR), role in normal mouse mammary gland development, mechanisms of transformation of mammary epithelial cells in vitro and in mouse models, and roles in human breast cancer. The second area of research is studies on tumor heterogeneity and molecular changes during progression, with a particular focus on DNA and RNA structural rearrangements. The laboratory participated in the first comprehensive report of structural rearrangements in a breast cancer cell line (MCF7) and reported on a novel massively parallel fosmid-based mate-pair assay for determining structural rearrangements. This work focuses on different tumor areas, or tumors from different parts of the body (obtained via rapid autopsy) to identify novel changes that may offer therapeutic insight. In addition, the University of Pittsburgh is the largest contributor of tissue to The Cancer Genome Atlas (TCGA), and many results are validated in these index cases.
Dr. Monga's laboratory is focused on understanding the molecular mechanisms of liver growth and development in health and disease, especially in the context of regeneration and cancer. Several signaling pathways have been identified to direct such events, including the Wnt/beta-catenin, HGF/Met, and PDGFR pathways.
Liver development in mice is initiated at around E8-8.5 stages of gestational development. Once foregut endoderm gains competence hepatic signatures are initiated during the process of which undergo expansion and regulated differentiation into hepatocytes and biliary epithelial cells during the process of morphogenesis. One of the major focuses of the Monga laboratory is to identify the molecular basis of hepatic morphogenesis. More specificallyinduction. The primitive liver bud contains bipotential stem cells or progenitors how does the hepatic progenitor or the bipotential stem cell undergo self-renewal (symmetric division) lineage specification and differentiate further towards primitive bile duct cells or immature hepatocytes (asymmetric division) and then to fully differentiated cells? Using conditional null mice embryonic liver cultures and other modalities the lab is investigating the roles regulation and interactions of various pathways which will not only further our understanding of this fundamental biological process but might also provide insight into the molecular basis of disease that recapitulates development in adulthood hepatocellular cancer (HCC). HCC is the third leading cause of cancer death and remains a disease with poor treatment options. Targeting pathways that are normally upregulated during liver development at the time of peak proliferation and stem cell renewal represents a novel therapeutic measure for the treatment of HCC."
The main interest of Dr. Oesterreich's laboratory is to further our understanding of hormone action in women's cancers (including both breast and ovarian cancers), with the ultimate goal to use this knowledge for improved diagnosis and endocrine treatment. These studies include many aspects of translational breast cancer research utilizing basic biochemistry, molecular and cell biology, and cell lines, mouse models and clinical samples. Over the last few years, Dr. Oesterreich has developed a strong research interest in in situ and invasive lobular disease, the second most common yet understudied histological subtype of breast cancer. In her role as Director of Education at the Women's Cancer Research Center, Dr. Oesterreich is also very interested in providing outstanding training opportunities to the next generation of women's cancer researchers.
Dr. Prochownik is interested in cancers resulting from the de-regulated expression of the c-Myc oncoprotein. He is using animal models of pediatric and adult liver cancer (hepatoblastoma and hepatocellular carcinoma) to ascertain the molecular, biochemical and metabolic changes that accompany tumor progression, regression and recurrence. He is utilizing over-expression and knockout models to determine how genes that cooperate with or are affected by Myc such as ChREBP and pyruvate dehydrogenase specifically contribute to the metabolic and molecular landscapes of these tumors.
The goal of our laboratory is to develop an independent and multidisciplinary research program at the interface of biomaterials, controlled drug delivery, and tissue engineering. We use an interdisciplinary approach to build biomimetic microenvironments in vitro based on our expertise in the pharmaceutical sciences, materials sciences, cell biology and micro/nanotechnologies. Specifically, we aim to develop tissue-engineered tumor models that recreate the three-dimensional structure, cell-cell/cell-matrix interaction, stromal environments, and signalling cues present in vivo. These three-dimensional models will be used for understanding the pathophysiology of the disease as well as for preclinical evaluation of drug safety and efficacy.
One major focus of my research is to identify and characterize androgen-response genes in the prostate. One of the androgen response genes, U19/EAF2, plays an essential role in androgen action and prostate cancer progression. U19/EAF2 is directly regulated by androgens in prostate epithelial cells. U19/EAF2 downregulation and loss of heterozygosity were observed in more than 80% of advanced human prostate cancer specimens, indicating its essential role in prostate cancer progression. Overexpression of U19/EAF2 in all of the assayed prostate cancer cell lines induced apoptosis both in vitro and in vivo. Furthermore, we showed that U19/EAF2 gene knockout in mice resulted in lung adenocarcinoma, hepatocellular carcinoma, and B cell lymphoma, demonstrating that U19 is a tumor suppressor. Although no prostate cancer was detected in U19 knockout mice, prostate hyperplasia and high grade PIN (prostatic epithelial neoplasia) was observed in the prostate, demonstrating that U19/EAF2 plays a critical role in prostate cancer. Our current research focuses on the roles of U19-binding partners and U19-downstream genes.
Another area of research interest is androgen receptor (AR) intracellular trafficking in prostate cancer cells, especially in androgen-refractory prostate cancer cells. In androgen-sensitive prostate cancer cells, AR is localized to the cytoplasm in the absence of ligand. The presence of ligand induces nuclear translocation of AR and the nuclear localized, liganded-AR transactivates downstream genes. However, in androgen-refractory prostate cancer cells, AR is localized to the nucleus in the absence or presence of ligand. Ligand-independent AR activation is thought to play a critical role in the development of androgen-refractory prostate cancer. Ligand-independent AR nuclear localization is a prerequisite for AR to undergo ligand-independent activation. Elucidating the mechanism of AR ligand-independent nuclear localization may provide insights into the mechanism of androgen-refractory prostate cancer development, which may lead to new targets for the treatment of androgen-refractory prostate cancer.
We are also interested in translating our research findings into prostate cancer patient treatment. We plan to determine whether intermittent androgen ablation therapy (IAAT) of prostate cancer can be enhanced by 5 alpha-reductase inhibitor, which blocks testosterone conversion to dihydrotestosterone (DHT). We have generated preliminary data indicating that inhibition of the conversion of testosterone to DHT by 5 alpha-reductase inhibitor can enhance the expression of tumor suppressive androgen-response genes during the regrowth of a regressed normal or cancerous prostate. The enhanced expression of tumor-suppressive androgen-response genes should retard the tumor regrowth. Using an androgen-sensitive human prostate xenograft tumor as a model, we showed that 5 alpha-reductase inhibitor finasteride enhanced the efficacy of IAAT. We are establishing collaborations with medical oncologists, urologists, and pathologists to evaluate whether IAAT can be enhanced by 5 alpha-reductase inhibitors in a clinical trial.
In collaborations with Drs. Joel Nelson, Paul Johnston, and Peter Wipf, our lab is trying to identify and develop small molecular inhibitors of AR nuclear localization and function in prostate cancer cells, particularly in castration-resistant prostate cancer cells. Recent studies showed that these small molecules can inhibit prostate cancer cells resistant to the second generation anti-androgen MDV3100. Ongoing research will identify analogs of our lead compounds for pre-clinical and clinical studies.
In addition to specializing in pediatric and adult orthopaedic oncology, Dr. Weiss directs a basic science laboratory dedicated to the study of sarcomas ' cancerous tumors that arise in musculoskeletal tissues. As a bone cancer survivor himself, Dr. Weiss brings passion and enthusiasm to the laboratory, clinic, and operating room.