Lung cancer is the leading cause of cancer related deaths in the United States, with an estimated 158, 040 deaths in 2015, accounting for 27% of all cancer deaths. Recent research has identified several important molecular driver oncogenes, including epidermal growth factor receptor (EGFR). EGFR is encoded by exons 18-21, each of which harbor specific mutations within the tyrosine kinase domain. These mutations can drive cell growth, proliferation, and survival, resulting in the formation of non-small cell lung cancer. The development of EGFR tyrosine kinase inhibitors, allows the targeting of these specific mutations without the toxicity normally associated with standard chemotherapy. Unfortunately, inevitably resistance to therapy manifests, requiring a change in therapy and adding complexity to treatment decision making for clinicians and patients alike. Through a comprehensive examination of current literature, this review will establish a standard for first line, targeted treatment for specific genetic mutations within the EGFR gene, as well as address treatment options once resistance to first-line therapy inevitably develops.

VIP is neurotransmitter with pleiotropic functions in mammals. It is expressed by a large number of tissues, including the CNS, PNS, innate and adaptive immune systems. VIP has two endogenous G-protein coupled receptors, termed VPAC 1 and VPAC2. VIP signaling through VPAC1 receptor has been documented to transactivate EGFR in healthy and cancerous cells leading to the activation of multiple downstream signaling pathways. EGFR signaling is a potent inducer of the master regulator EMT, called Snail1, which is a zinc-finger, transcription factor that is associated with downregulating epithelial markers like E-cadherin, while upregulating mesenchymal markers necessary for invasion and metastasis. We hypothesize that VIP upregulates Snail1expression in cancer cells. Our results showed that VIP treatment of epithelial cells increased Snail1 expression transiently at 1h and 4h then returned to basal levels at 24h. This research has implications in development of targeted therapies for cancer.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18848号 / 医博第3959号 / 新制||医||1007(附属図書館) / 31799 / 京都大学大学院医学研究科医学専攻 / (主査)教授 岩田 想, 教授 岩井 一宏, 教授 楠見 明弘 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Head and neck squamous cell carcinoma (HNSCC) develops in mucous membranes that line the mouth, throat and sinuses. It is the sixth most common cancer worldwide with more than 600,000 new cases diagnosed every year. The 5 year survival of HNSCC patients is less than 50% after initial diagnosis, while median survival after relapse or metastasis is less than one year. Unfortunately, the prognosis of HNSCC has not changed in the last two decades, mostly due to the poor understanding of the mechanism of this disease. New therapeutic targets and agents are in urgent need.

No description available.

No description available.

No description available.

Glioblastoma Multiforme (GBM) is the most common and malignant form of adult brain cancer, with 95% of patients succumbing to the disease within 5 years of diagnosis. An important contributing factor to this poor prognosis is upregulation of the transmembrane protein system xc- (SXC) found on GBM cells. Approximately 50% of GBM patients have tumors with upregulated levels of SXC, and these patients experience faster disease progression than patients with tumors expressing moderate levels of SXC. SXC is a sodium-independent antiporter and is comprised of a light chain catalytic subunit (xCT) bound to a heavy chain regulatory subunit (4f2hc/CD98) via a disulfide bond. The xCT subunit is responsible for the equimolar exchange of extracellular cystine for intracellular glutamate. Clinical studies have shown areas immediately surrounding the tumor, known as the peritumoral region, reach glutamate concentrations over 100 times that of the normal brain, creating an excitotoxic environment in which neurons cannot survive. In addition to neuronal excitotoxicity, excess glutamate release has also been shown to promote GBM cell invasion, as well as contributing to the clinical presentation of seizures in patients. Moreover, cystine is a component of the antioxidant glutathione, which confers protection to the cells from alkylating therapeutics such as temozolomide (TMZ). In an effort to identify novel targets that regulate SXC function, I investigated the relationship between SXC and two signaling molecules known to promote GBM progression: CD44 and the epidermal growth factor receptor (EGFR). I experimentally manipulated the CD44-hyaluronic acid (HA) interaction and EGFR to determine if these two signaling molecules were involved in regulating SXC expression and function in two patient-derived GBM cell lines. Experimental data led me to conclude that the tumorigenic potential conferred to GBM cells by CD44 is not related to an interaction with SXC. However, I found that knocking down EGFR led to a significant reduction in SXC expression. These findings are important to the field, as combinatorial therapies become more actively pursued in clinical trials. Inhibition of EGFR may provide quality of life benefits to patients who suffer from tumor-associated epilepsy through downregulating xCT-mediated glutamate release. / Doctor of Philosophy / Glioblastoma multiforme (GBM) is an advanced and aggressive form of brain cancer. Incidence of this disease in the United States of America is approximately 3.19 per 100,000 individuals, which translates to more than 13,000 expected annual diagnoses. These tumors arise from genetic mutations that instruct cells to replicate and migrate abnormally. Despite an aggressive medical armamentarium that includes maximal surgical resection, chemotherapy, and radiation, GBM patients have an expected survival period of 12-15 months after diagnosis. Previous studies have shown that approximately 50% of GBM patients have unusually high expression levels of the System xc- (SXC) protein. SXC is a protein transporter located at the membrane of GBM cells, and facilitates the exchange of the excitatory neurotransmitter glutamate for the amino acid dimer cystine. SXC exports glutamate out of the tumor cell, where it can then bind to glutamate receptors on surrounding neurons. In the brain, the concentration of extracellular glutamate must be tightly regulated to prevent hyperexcitability of neurons, which may lead to cell death and the induction of seizures. In patients whose tumors highly express SXC, studies have shown that glutamate levels can rise to concentrations over 100 times greater than the levels seen in normal brain tissue. Additionally, glutamate has been shown to stimulate GBM cells to migrate within the brain and establish secondary tumor sites. The medical and scientific community is justifiably interested in discovering novel methods for regulating or inhibiting SXC-mediated glutamate release. While SXC inhibitors have been identified, clinical studies have determined they are not appropriate for the clinical treatment of GBM. Thus the focus of this project was to identify novel molecular regulators of SXC. To that end, I explored two signaling molecules that are known to promote GBM pathogenesis: CD44 and the epidermal growth factor receptor (EGFR). I found no evidence to support a role for CD44 in regulating SXC in GBM. However, I was able to determine, through genetic and pharmacologic manipulation of patient-derived GBM cells, that EGFR regulates SXC expression and function. The results of these experiments confirmed EGFR as a key signaling protein involved in orchestrating SXC-mediated glutamate release, and may inform future clinical studies investigating combinatorial therapies for GBM patients.

Previous studies of human oligodendroglial neoplasms have demonstrated the diagnostic and prognostic values of histomorphologic features and immunocytochemical markers. Primary spontaneous canine intracranial tumors share many of the biologic behaviors and pathologic features of their human counterparts. The objectives of this study were to determine if associations existed between five histomorphologic features (mitoses, cellular atypia, necrosis, vascular hypertrophy, and vascular proliferation), and three immunocytochemical markers (GFAP, EGFR, and Ki-67 labeling index) and the degree of malignancy, as defined by WHO grading criteria, of 15 canine oligodendroglial tumors. Of the histomorphologic variables examined, mitoses and cellular atypia were significantly greater in Grade III oligodendrogliomas than in Grade II oligodendrogliomas (p = 0.002, and p = 0.004, respectively), but no differences were noted between these features and Grade II oligoastrocytomas and Grade II or Grade III oligodendrogliomas. No significant associations were found between GFAP or EGFR immunoreactivity and tumor type or grade. The median percentage of Ki-67 immunoreactivity was significantly different between all tumor types and grades (p < 0.05), and was significantly higher in Grade III oligodendrogliomas than in both oligoastrocytomas (p = 0.014) and Grade II oligodendrogliomas (p = 0.006). Results of this study indicate that although mitoses and cellular atypia are useful histomorphologic features for the differentiation of tumors with oligodendroglial phenotypes, none of the variables examined reliably distinguished mixed gliomas from oligodendrogliomas. The presence of GFAP immunoreactivity in all tumor types suggests that oligodendroglial tumors may arise from a common multipotential cellular lineage. Similar to what has been demonstrated in humans, the Ki-67 labeling index correlated well with the degree of malignancy in the tumors studied. / Master of Science

Les ultraviolets A (UVA) sont carcinogènes et produisent des espèces réactives de l'oxygène (ERO). Le récepteur à la mélanocortine de type 1 (MC1R) est un récepteur couplé aux protéines G (RCPG) qui est impliqué dans la mélanogénèse et dans l'inflammation cutanée. Certains variants du gène sont associés à un risque accru de mélanomes et de carcinomes cutanés. Le MC1R est exprimé surtout dans les mélanocytes mais son expression peut être induite par les UV in vitro dans les kératinocytes et in vivo dans la peau. Le récepteur MC1R est activé par l'α-MSH. L'objectif de ce travail de thèse a été d'étudier les effets du récepteur MC1R sur le stress oxydatif induit par les UVA dans des lignées kératinocytaires humaines HaCaT exprimant le récepteur MC1R ou son variant non fonctionnel Arg151Cys. Nous avons montré que la production d'ERO intracellulaire induite par les UVA est fortement inhibée dans les cellules HaCaT-MC1R et que cette inhibition est renforcée en présence d'α-MSH. L'inhibition du stress oxydatif induit par les UVA dans les cellules transfectées par le MC1R est en partie dépendante de la phosphorylation de la sous-unité activatrice, NoxA1 de la NADPH oxydase. Le traitement des cellules HaCaT-MC1R par un inhibiteur du récepteur au facteur de croissance épidermique (EGFR) restaure l'habilité de ces cellules à induire un stress oxydatif après irradiation UVA. Ces résultats montrent que l'activité constitutive du récepteur MC1R dans des kératinocytes pourrait inhiber le stress oxydatif induit par les UVA via des mécanismes dépendants de l'AMPc et de l'EGFR. / Ultraviolet A (UVA) radiations are responsible for deleterious effects, mainly due to reactive oxygen species (ROS) production. Alpha-melanocyte stimulating hormone (α-MSH) binds to Melanocortin-1 Receptor (MC1R) in melanocytes to stimulate pigmentation and modulate cutaneous inflammatory responses. MC1R may be induced in keratinocytes after UV exposure. To investigate the effect of MC1R signaling on UVA-induced ROS (UVA-ROS) production, we generated HaCaT cells that stably express human MC1R (HaCaT-MC1R) or the Arg151Cys (R151C) non- functional variant (HaCaT-R151C). We then assessed ROS production immediately after UVA exposure and found that: (1) UVA-ROS production was strongly reduced in HaCaT-MC1R but not in HaCaT-R151C cells compared to parental HaCaT cells; (2) this inhibitory effect was further amplified by α-MSH treatment of HaCaT-MC1R cells before UVA exposure; (3) after UVA irradiation, NoxA1 phosphorylation was increased i n HaCaT-MC1R compared to HaCaT and HaCaT-R151C cells. Inhibition of PKA in HaCaT-MC1R cells resulted in a marked increase of UVA-ROS production; (4) the ability of HaCaT-MC1R cells to produce UVA-ROS was restored by inhibiting epidermal growth factor receptor (EGFR) or extracellular signal-regulated kinases (ERK) activity before UVA exposure. Our findings suggest that constitutive activity of MC1R in keratinocytes may reduce UVA-induced oxidative stress via EGFR and cAMP-dependent mechanisms.