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Item A C-X-C Chemokine Receptor Type 2–Dominated Cross-talk between Tumor Cells and Macrophages Drives Gastric Cancer Metastasis(AACR, 2019-06) Zhou, Zhijun; Xia, Guanggai; Xiang, Zhen; Liu, Mingyang; Wei, Zhewei; Yan, Jie; Chen, Wei; Zhu, Jintao; Awasthi, Niranjan; Sun, Xiaotian; Fung, Kar-Ming; He, Yulong; Li, Min; Zhang, Changhua; Surgery, School of MedicinePurpose: C-X-C chemokine receptor type 2 (CXCR2) is a key regulator that drives immune suppression and inflammation in tumor microenvironment. CXCR2-targeted therapy has shown promising results in several solid tumors. However, the underlying mechanism of CXCR2-mediated cross-talk between gastric cancer cells and macrophages still remains unclear. Experimental Design: The expression of CXCR2 and its ligands in 155 human gastric cancer tissues was analyzed via immunohistochemistry, and the correlations with clinical characteristics were evaluated. A coculture system was established, and functional assays, including ELISA, transwell, cell viability assay, and qPCR, were performed to determine the role of the CXCR2 signaling axis in promoting gastric cancer growth and metastasis. A xenograft gastric cancer model and a lymph node metastasis model were established to study the function of CXCR2 in vivo. Results: CXCR2 expression is associated with the prognosis of patients with gastric cancer (P = 0.002). Of all the CXCR2 ligands, CXCL1 and CXCL5 can significantly promote migration of gastric cancer cells. Macrophages are the major sources of CXCL1 and CXCL5 in the gastric cancer microenvironment, and promote migration of gastric cancer cells through activating a CXCR2/STAT3 feed-forward loop. Gastric cancer cells secrete TNF-α to induce release of CXCL1 and CXCL5 from macrophages. Inhibiting CXCR2 pathway of gastric cancer cells can suppress migration and metastasis of gastric cancer in vitro and in vivo. Conclusions: Our study suggested a previously uncharacterized mechanism through which gastric cancer cells interact with macrophages to promote tumor growth and metastasis, suggesting that CXCR2 may serve as a promising therapeutic target to treat gastric cancer.Item A genome-wide analysis of gene–caffeine consumption interaction on basal cell carcinoma(Oxford University Press, 2016-12) Li, Xin; Cornelis, Marilyn C.; Liang, Liming; Song, Fengju; De Vivo, Immaculata; Giovannucci, Edward; Tang, Jean Y.; Han, Jiali; Epidemiology, School of Public Healthp53 plays an important role in silibinin-mediated inhibition of UVB-induced skin carcinogenesis and associated inflammatory response in SKH-1 hairless mouse. Silibinin-mediated repair of UVB-induced DNA damage is only partially dependent on p53., Animal models have suggested that oral or topical administration of caffeine could inhibit ultraviolet-induced carcinogenesis via the ataxia telangiectasia and rad3 (ATR)-related apoptosis. Previous epidemiological studies have demonstrated that increased caffeine consumption is associated with reduced risk of basal cell carcinoma (BCC). To identify common genetic markers that may modify this association, we tested gene–caffeine intake interaction on BCC risk in a genome-wide analysis. We included 3383 BCC cases and 8528 controls of European ancestry from the Nurses’ Health Study and Health Professionals Follow-up Study. Single nucleotide polymorphism (SNP) rs142310826 near the NEIL3 gene showed a genome-wide significant interaction with caffeine consumption (P = 1.78 × 10–8 for interaction) on BCC risk. There was no gender difference for this interaction (P = 0.64 for heterogeneity). NEIL3, a gene belonging to the base excision DNA repair pathway, encodes a DNA glycosylase that recognizes and removes lesions produced by oxidative stress. In addition, we identified several loci with P value for interaction <5 × 10–7 in gender-specific analyses (P for heterogeneity between genders < 0.001) including those mapping to the genes LRRTM4, ATF3 and DCLRE1C in women and POTEA in men. Finally, we tested the associations between caffeine consumption-related SNPs reported by previous genome-wide association studies and risk of BCC, both individually and jointly, but found no significant association. In sum, we identified a DNA repair gene that could be involved in caffeine-mediated skin tumor inhibition. Further studies are warranted to confirm these findings.Item Genome-Wide Interaction Analysis of Genetic Variants With Menopausal Hormone Therapy for Colorectal Cancer Risk(Oxford, 2022) Tian, Yu; Kim, Andre E.; Bien, Stephanie A.; Lin, Yi; Qu, Conghui; Harrison, Tabitha A.; Carreras-Torres, Robert; Díez-Obrero, Virginia; Dimou, Niki; Drew , David A.; Hidaka, Akihisa; Huyghe, Jeroen R.; Jordahl, Kristina M.; Morrison , John; Murphy, Neil; Obón-Santacana, Mireia; Ulrich, Cornelia M.; Ose, Jennifer; Peoples, Anita R.; Ruiz-Narvaez, Edward A.; Shcherbina, Anna; Stern , Mariana C.; Su, Yu-Ru; van Duijnhoven, Franzel J. B.; Arndt, Volker; Baurley, James W.; Berndt, Sonja I.; Bishop, D. Timothy; Brenner, Hermann; Buchanan, Daniel D.; Chan, Andrew T.; Figueiredo, Jane C.; Gallinger, Steven; Gruber, Stephen B.; Harlid, Sophia; Hoffmeister, Michael; Jenkins, Mark A.; Joshi, Amit D.; Keku, Temitope O.; Larsson, Susanna C.; Marchand, Loic Le; Li, Li; Giles, Graham G.; Milne, Roger L.; Nan, Hongmei; Nassir, Rami; Ogino, Shuji; Budiarto, Arif; Platz, Elizabeth A.; Potter, John D.; Prentice, Ross L.; Rennert, Gad; Sakoda, Lori C.; Schoen, Robert E.; Slattery, Martha L.; Thibodeau, Stephen N.; Van Guelpen, Bethany; Visvanathan, Kala; White, Emily; Wolk, Alicja; Woods, Michael O.; Wu, Anna H.; Campbell, Peter T.; Casey, Graham; Conti, David V.; Gunter, Marc J.; Kundaje, Anshul; Lewinger, Juan Pablo; Moreno, Victor; Newcomb, Polly A.; Pardamean, Bens; Thomas, Duncan C.; Tsilidis, Konstantinos K.; Peters, Ulrike; Gauderman, W. James; Hsu, Li; Chang-Claude, Jenny; Global Health, School of Public HealthBackground: The use of menopausal hormone therapy (MHT) may interact with genetic variants to influence colorectal cancer (CRC) risk. Methods: We conducted a genome-wide, gene-environment interaction between single nucleotide polymorphisms and the use of any MHT, estrogen only, and combined estrogen-progestogen therapy with CRC risk, among 28 486 postmenopausal women (11 519 CRC patients and 16 967 participants without CRC) from 38 studies, using logistic regression, 2-step method, and 2– or 3–degree-of-freedom joint test. A set-based score test was applied for rare genetic variants. Results: The use of any MHT, estrogen only and estrogen-progestogen were associated with a reduced CRC risk (odds ratio [OR] = 0.71, 95% confidence interval [CI] = 0.64 to 0.78; OR = 0.65, 95% CI = 0.53 to 0.79; and OR = 0.73, 95% CI = 0.59 to 0.90, respectively). The 2-step method identified a statistically significant interaction between a GRIN2B variant rs117868593 and MHT use, whereby MHT-associated CRC risk was statistically significantly reduced in women with the GG genotype (OR = 0.68, 95% CI = 0.64 to 0.72) but not within strata of GC or CC genotypes. A statistically significant interaction between a DCBLD1 intronic variant at 6q22.1 (rs10782186) and MHT use was identified by the 2–degree-of-freedom joint test. The MHT-associated CRC risk was reduced with increasing number of rs10782186-C alleles, showing odds ratios of 0.78 (95% CI = 0.70 to 0.87) for TT, 0.68 (95% CI = 0.63 to 0.73) for TC, and 0.66 (95% CI = 0.60 to 0.74) for CC genotypes. In addition, 5 genes in rare variant analysis showed suggestive interactions with MHT (2-sided P < 1.2 × 10−4). Conclusion: Genetic variants that modify the association between MHT and CRC risk were identified, offering new insights into pathways of CRC carcinogenesis and potential mechanisms involved.Item Mitochondrial DNA Copy Number, Insulinemic Potential of Lifestyle, and Colorectal Cancer(2020-03) Yang, Keming; Nan, Hongmei; Forman, Michele R.; Graham, Brett H.; Han, Jiali; Monahan, Patrick O.Because colorectal cancer (CRC) is the fourth most common cancer and the second leading cause of cancer death in the US, identifying biomarkers that might inform disease prevention and early diagnosis is of great public health importance. Mitochondria are key cytoplasmic organelles containing an independent genome, i.e., mitochondrial DNA (mtDNA). It has been increasingly recognized that mtDNA copy number (mtDNAcn) is a biomarker for mitochondrial function and cellular oxidative stress. To date, the few studies that have assessed associations between mtDNAcn and CRC outcomes have yielded inconsistent findings. Further, no epidemiologic study has examined the relationship between insulinemic potential of lifestyle and mtDNAcn. Therefore, in this dissertation, three studies were conducted using data from the Nurses’ Health Study and the Health Professionals Follow-Up Study. First, the association between pre-diagnostic leukocyte mtDNAcn and CRC risk was studied in a nested casecontrol study (324 cases/658 controls). Lower mtDNAcn was significantly associated with increased risk of CRC and proximal colon cancer. That inverse association remained significant among individuals with ≥ 8 years’ follow-up since blood collection, suggesting that mtDNAcn might serve as a long-term predictor of CRC risk. Second, possible associations of pre-diagnostic mtDNAcn with overall and CRC-specific survival were examined among 587 CRC patients. MtDNAcn was not significantly associated with survival overall or in subgroups by cancer location, grade, or stage. Among current smokers, there was an inverse association between one standard deviation (SD) decrease in mtDNAcn and increased overall death risk. Among patients diagnosed at or before 70.5 years of age and those with anti-inflammatory diets, reduced mtDNAcn was associated with lower CRC-specific death risk. Lastly, the cross-sectional association between empirical lifestyle index for hyperinsulinemia (ELIH) and mtDNAcn was investigated among 2,835 subjects without major chronic diseases (cancers, diabetes, and cardiovascular diseases). A significant inverse association was found: least-squares means ± SD of mtDNAcn z-score decreased dramatically across ELIH quintiles. Overall, the findings from this dissertation will contribute to the evaluation of mtDNAcn as a potential biomarker for CRC risk and prognosis, and inform future interventions designed to reduce the insulinemic potential of lifestyle factors to preserve mitochondrial function.