The program in this area specifically focuses on tumor progression, invasion and metastasis and UV carcinogenesis. Inflammatory Breast Cancer: Dr. Barsky’s laboratory goal is to understand the molecular basis of inflammatory breast cancer using a novel human xenograft model of inflammatory breast cancer and human cancer cell myoepithelial interactions. A number of new abstracts and manuscripts have been communicated. Chemokines and Metastasis: Dr Ganju’s laboratory is analyzing the role of the chemokine receptor CXCR4 in breast cancer metastasis and its inhibition by a novel Slit/Robo complex. It has recently been shown that the chemokine receptor CXCR4 and its ligand CXCL12 play a critical role in breast cancer metastasis. Dr. Ganju’s laboratory has elucidated novel signaling pathways mediated by CXCR4 that regulate the CXCL12-induced chemotaxis, chemoinvasion, and adhesion of breast cancer cells. In this context, they have shown that focal adhesion kinases, Cbl, and tyrosine phosphates play an important role in breast cancer cell chemotaxis/chemoinvasion. They are also developing innovative strategies to block the CXCR4-mediated metastasis of breast cancer cells. In this regard, they have shown that the Slit protein, which binds to the Robo receptor, blocks the CXCR4-induced chemotaxis, chemoinvasion, and adhesion of breast cancer cells. Further analysis of Slit-mediated anti-tumorigenic and metastatic mechanisms revealed that Slit down modulates the expression of psoriasin. Psoriasin is among the most highly expressed genes in breast cancer patients with pre-invasive ductal carcinoma in situ. Furthermore, a poor prognosis is associated with the persistent expression of psoriasin in invasive carcinoma. Dr. Ganju’s laboratory has shown that various growth factors regulate psoriasin expression and that psoriasin may regulate osteoclast formation as well as breast cancer metastasis to bone. They are further elucidating the signaling mechanism through which psoriasin may modulate the growth and metastasis of breast cancer. Dr Ganju’s laboratory is also identifying small molecular weight molecules that have potential to be used as drugs to block metastasis. In this regard they have shown that cannabinoids, which are small molecular weight molecules, inhibit the CXCR4-mediated functions of immune cells. In preliminary studies, they have further found that these compounds, which mediate their effects through the cannabinoid receptors CB1 and CB2, can block the growth and chemotaxis of lung cancer cell lines and breast cancer cell lines under in vitro and in-vivo conditions. They are further analyzing the cannabinoid-mediated molecular mechanism of inhibition of growth and metastasis. UV Carcinogenesis: Dr. Tatiana Oberyszyn’s laboratory has continued working on understanding the development of squamous cell carcinoma of the skin. Three separate projects examining the effects of UVB exposure on the skin are being pursued. Dr. Oberyszyn’s laboratory are studying the importance of gender in the development of UVB-induced skin cancer. They have found that while skin of male mice exposed to 1 minimal erythemic dose of UVB demonstrated a dampened inflammatory response compared to female skin, they ultimately developed a larger number of UVB-induced tumors and had more tumors of a higher grade than female mice. Furthermore, they have shown that the skin of male mice not only contained higher levels of the oxidative DNA adduct 8-oxodG, but also contained lower endogenous levels of total antioxidant activity. This data has been published in Cancer Research. In addition, studies suggest that male skin has lower levels of OGG1, the repair enzyme for 8-oxo-dG. Taken together, these data suggest that male skin may not only be less able to prevent UVB-induced DNA damage, but also less able to repair oxidative DNA damage. Dr. Oberyszyn’s laboratory is further pursuing the identification of the activity of various specific antioxidants in male vs. female skin. These studies are part of a RO1 application currently in review at NIH. Dr. Oberyszyn’s laboratory is also studying the role of therapeutic immunosuppression in the development of UVB induced skin cancer. Solid organ transplant recipients are between 65-250 times more likely to develop squamous cell carcinomas of the skin and exhibit an increased morbidity and mortality compared to the general population. The immunosuppressive therapy required to maintaining the integrity of the transplanted organs is believed to play a role in the increased SCC but how that is occurring is currently not clear. Dr. Oberyszyn’s laboratory uses the Shk-1 hairless murine model to attempt to understand this process. To mimic transplant patients who generally receive transplants in their 40-50’s following a lifetime of sunlight exposure, Skh-1 hairless mice were exposed to UVB for 15 weeks and then began treating with the therapeutically relevant drugs Cyclosporine (CsA) or Rapamycin (SRL) for 9 weeks following cessation of UVB treatment. Compared to vehicle, CsA treatment resulted in enhanced tumor size and progression. In contrast, mice treated with SRL had decreased tumor multiplicity, size, and progression compared to vehicle-treated mice. CsA, but not SRL, increased dermal mast cell number and TGFβ1 levels in the skin. These findings demonstrate that specific immunosuppressive agents differentially alter the cutaneous tumor microenvironment, which in turn may contribute to the enhanced development of UVB-induced skin cancer in transplant recipients. Furthermore, these results suggest that even without any additional UVB exposure, treatment with CsA can cause enhanced growth and progression of skin cancer in previously UVB exposed skin. Dr. Oberyszyn’s laboratory is also studying the effect of topical treatment with Black Raspberry extract (BRE) on UVB-induced inflammation and carcinogenesis. Dr. Oberyszyn’s laboratory, as well as others, has previously shown that in females, there is a link between UVB induced inflammation and ultimate cutaneous tumor development. BRE contains potent anthocyanins, which have been shown to have anti-inflammatory and anti-oxidant effects. There are two ongoing clinical trials being spearheaded by Dr. Gary Stoner, examining the efficacy of BRE in preventing oral cancers as well as recurrence of colon tumors. Our studies in the Skh-1 murine model have found that topical treatment with BRE following UVB exposure is a potent inhibitor of the acute inflammatory response. Furthermore, treatment with BRE in UVB carcinogenesis protocol significantly decreased the number of cutaneous tumors. We are currently in the middle of a carcinogenesis trial to see if topical BRE treatment will affect tumor development in CsA treated mice Dr. Oberyszyn’s laboratory is analyzing the importance of the EP1 receptor in the development of UVB-induced SCC. Dr. Oberyszyn’s laboratory has previously shown that topical treatment with the specific COX-2 inhibitor celecoxib decreases UVB induced inflammation and tumor development by about 50-60%. Since specific COX-2 inhibitors have been shown to have unanticipated cardiac side effects, her laboratory explored the effectiveness of blocking signaling of COX-2 generated PGE2 via on of it’s specific receptors EP1. They found that topical treatment with a specific EP1 antagonist decreased UV-induced tumor development similar to that seen following topical celecoxib treatment. They used immunohistochemical analysis to localize the expression of the four EP receptors in the skin and found that EP1 is expressed in the outermost layer of the epidermis while EP3 localized to the basal layer in non-UVB exposed epidermis. Exposure to UVB resulted in the relocalization of only the EP3 receptor to the entire epidermis. Interestingly while topical treatment with the EP1 antagonist had no effect on EP1 localization, it did prevent the relocalization of EP3. This data suggests an as of yet unreported interaction between the two receptors. We are currently pursuing studies designed to determine the importance of this interaction in skin tumor development. Cell Cycle and Cancer: Dr. Zou, who studies cancer cell cycle regeneration, recently joined the department. His laboratory is elucidating the role of Cyclin-dependent kinases Cdk4/6 in differentiation, senescence and cancer. Alterations in the Arf/p53 or Ink4a/Rb pathway are the most frequent genetic lesions in a variety of human tumors including breast cancer and the cancer with the genetic alterations are resistant to many anticancer agents and difficult to treat. It remains a considerable challenge to effectively prevent and treat human cancers with inactivation of p53 or Ink4a/Arf. Dr. Zou’s laboratory has discovered that Cdk4 gene disruption results in cell resistant to oncogenic transformation, leading to Arf/p53-independent senescence. These novel findings have very important implications and clues for treatment of human tumors with p53 /Arf deficiency. His laboratory is investigating the detailed mechanism of the senescence resulting from Cdk4/6 inhibition in vitro in human cancer cells and in vivo using various mouse model systems. They are also analyzing the role of CDC25A phosphatase in cell proliferation, apoptosis and cancer. More than 50% of breast cancers are shown to have an overexpression of Cdc25A, a protein that promotes cell division. Dr. Zou’s laboratory has shown that CdC25A overexpression suppresses stress-induced cell death by inhibiting apopotosis signal-regulating kinase 1(ASK1) and downstream JNK/p38 kinase cascades. These findings provide not only a novel clue to the interaction between the cell cycle machinery and stress-responsive mechanisms, but also a strong evidence that overexpression of CDC25A plays a critical role in transformation by the dual function of CDC25A on cell cycle progression and stress responses. It suggests that CDC25A could serve as a promising target for cancer therapeutic intervention. We will continue to investigate whether the reduced CDC25A expression represses or reduces tumorigenesis by mouse model. Immuneprevention and Immunotherapy of Cancer: Dr. Gao’s laboratory is developing novel strategies for immunoprevention and immunotherapy of cancer through the understanding of mechanisms underlying immuno editing effects on cancer development, especially on pCSC regression and progression. They are elucidating the significance of piwil2 in cancer development, and its application in early detection, prevention and treatment of cancer. They are establishing a series of pCSC and CSC lines from various types of human and animal cancers, and exploring common developmental pathways of various types of cancer through characterization of these unique cell lines. In addition, they are developing approaches for early detection, prevention and treatment of cancer. Their focus is on the biomarkers that are not only specific for cancer development, but also have the potential to be used for immunoprevention and immunotherapy of cancer. They are working on a novel model of cancer development, including a cellular process of tumor initiating cells (TICs) → precancerous stem cells (pCSCs) → cancer stem cells (CSCs) → cancer cells, which parallels to a histological process of cancer development: hyperplasia/metaplasia ie (TICs) → premalignant lesions (pCSCs) → malignant lesions (CSCs) → cancer. Glioblastoma Multiforme Pthogenesis: Dr. Van Brocklyn’s laboratory is delineating the role of sphingolipid signaling in glioblastoma multiforme (GBM). In particular, they have explored the regulation of GBM cell proliferation and invasiveness by sphingosine-1-phosphate (S1P) signaling through its G protein-coupled receptors. His laboratory has shown that S1P is mitogenic and that it enhances motility and invasiveness of some GBM cells. Furthermore, they have shown that elevated expression levels of the enzyme that forms S1P, sphingosine kinase (SphK), correlates with three fold reduced survival time of GBM patients. Recently they have also shown that S1P functions through upregulation of several genes known to be involved in GBM pathogenesis including urokinase plasminogen activator and its receptor as well as the pro-invasive and pro-angiogenic matricellular protein CCN1/Cyr61. In another project in progress, they have shown that SphK expression and activity are positively regulated by epidermal growth factor (EGF) signaling in GBM cells. As EGF receptor overexpression and mutation are common in GBM this is an intriguing find which they will continue to explore further. Dr. Van Brocklyn’s ultimate goal is to understand the roles that the SphK/S1P/S1P receptor signaling axis plays in GBM pathogenesis as well as to determine whether therapeutic approaches targeting this system are useful in GBM, particularly in the subgroup of GBMs expressing high levels of SphK.