Burden and Risk Factors of Brain Metastases in Melanoma: A Systematic Literature Review.

Melanoma can frequently metastasize to the brain with severe consequences. However, variation of melanoma brain metastases (MBM) development among populations is not well studied, and underlying mechanisms and risk factors for MBM development are not consistently documented. We conducted a systematic literature review (SLR) including a total of 39 articles to evaluate the proportion of melanoma patients who are diagnosed with, or develop, brain metastases, and summarize the risk factors of MBM. The average proportion of MBM was calculated and weighted by the sample size of each study. Meta-analyses were conducted for the selected risk factors using a random-effects model. The proportion of MBM at diagnosis was 33% (975 with MBM out of 2948 patients) among patients with cutaneous melanoma (excluding acral) and 23% (651/2875) among patients with cutaneous mixed with other types of melanoma. The proportion at diagnosis was lower among populations with mucosal (9/96, 9%) or uveal (4/184, 2%) melanoma and among populations outside the United States and Europe. Meta-analysis demonstrated that male vs. female gender and left-sided tumors vs. right-sided were significantly associated with increased risk of melanoma brain metastases. These data may help clinicians to assess an individual patient's risk of developing melanoma brain metastases.

Systematic literature review and meta-analysis of clinical outcomes and prognostic factors for melanoma brain metastases.

Background: More than 60% of all stage IV melanoma patients develop brain metastases, while melanoma brain metastases (MBM) is historically difficult to treat with poor prognosis. Objectives: To summarize clinical outcomes and prognostic factors in MBM patients. Methods: A systematic review with meta-analysis was conducted, and a literature search for relevant studies was performed on November 1, 2020. Weighted average of median overall survival (OS) was calculated by treatments. The random-effects model in conducting meta-analyses was applied. Results: A total of 41 observational studies and 12 clinical trials with our clinical outcomes of interest, and 31 observational studies addressing prognostic factors were selected. The most common treatments for MBM were immunotherapy (IO), MAP kinase inhibitor (MAPKi), stereotactic radiosurgery (SRS), SRS+MAPKi, and SRS+IO, with median OS from treatment start of 7.2, 8.6, 7.3, 7.3, and 14.1 months, respectively. Improved OS was observed for IO and SRS with the addition of IO and/or MAPKi, compared to no IO and SRS alone, respectively. Several prognostic factors were found to be significantly associated with OS in MBM. Conclusion: This study summarizes pertinent information regarding clinical outcomes and the association between patient characteristics and MBM prognosis.

Current Treatment Approaches and Global Consensus Guidelines for Brain Metastases in Melanoma.

Background: Up to 60% of melanoma patients develop melanoma brain metastases (MBM), which traditionally have a poor diagnosis. Current treatment strategies include immunotherapies (IO), targeted therapies (TT), and stereotactic radiosurgery (SRS), but there is considerable heterogeneity across worldwide consensus guidelines. Objective: To summarize current treatments and compare worldwide guidelines for the treatment of MBM. Methods: Review of global consensus treatment guidelines for MBM patients. Results: Substantial evidence supported that concurrent IO or TT plus SRS improves progression-free survival (PFS) and overall survival (OS). Guidelines are inconsistent with regards to recommendations for surgical resection of MBM, since surgical resection of symptomatic lesions alleviates neurological symptoms but does not improve OS. Whole-brain radiation therapy is not recommended by all guidelines due to negative effects on neurocognition but can be offered in rare palliative scenarios. Conclusion: Worldwide consensus guidelines consistently recommend up-front combination IO or TT with or without SRS for the treatment of MBM.

Identifying Anticipated Events of Future Clinical Trials by Leveraging Data from the Placebo Arms of Completed Trials.

BACKGROUND: An important component of a systematic strategy for safety surveillance is prospective identification of anticipated serious adverse events (SAEs). Developing a structured approach to identify anticipated events and estimating their incidence can help align the safety strategy and the safety surveillance efforts. METHODS: We developed a novel approach to identify anticipated events for a hypothetical randomized, double-blind, controlled trial in subjects with bipolar disorder using the adverse events reported in the placebo arm of trials from the ClinicalTrials.gov database. We searched the ClinicalTrials.gov database for all trials on bipolar depression with similar inclusion/exclusion criteria and study duration as our hypothetical study. The frequencies of anticipated events in placebo arms were abstracted from each trial and 95% confidence intervals (CI) were calculated using the Clopper-Pearson method. Meta-analysis with a random effects model was performed to obtain a summary estimate and 95% CI for the events identified in more than one trial. RESULTS: A total of 129 clinical trials were initially identified, and 18 were ultimately selected as they met all the selection criteria. There were 69 unique anticipated SAEs identified, and 13 out of 69 were reported in at least 2 clinical trials. The top 5 anticipated SAEs for our study were: (1) hospitalization, psychiatric symptom (3.57%); (2) suicidal behavior, overdose (3.57%), (3) cholecystitis (2.86%); (4) fall (2.86%); (5) road traffic accident, injury (2.86%). CONCLUSION: We successfully identified the anticipated events from registered trials that included a population similar to our trial. This method for identifying anticipated events could be applied to other disease areas.

Individual and joint effects of metformin and statins on mortality among patients with high-risk prostate cancer.

BACKGROUND: Pre-clinical studies suggest that metformin and statins may delay prostate cancer (PCa) metastases; however, data in humans are limited. To the best of our knowledge, this is the first human study aimed to quantify the individual and joint effects of statin and metformin use among patients with high-risk PCa. METHODS: This population-based retrospective cohort study identified patients from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database. Exposure to metformin and statins was ascertained from Medicare Prescription Drug Event files. The association with all-cause and PCa mortality were evaluated using Cox proportional hazard model with competing causes of death, where propensity scores were used to adjusted imbalances in covariates across groups. RESULTS: Based on 12 700 patients with high-risk PCa, statin alone or in combination with metformin was significantly associated with reduced all-cause mortality (Hazard Ratio [HR]: 0.89; 95% Confidence Interval [CI]: 0.83, 0.96; and HR: 0.75; 95% CI, 0.67-0.83, respectively) and PCa mortality (HR, 0.80; 95% CI: 0.69, 0.92) and 0.64; 95% CI, d 0.51-0.81, respectively. The effects were more pronounced in post-diagnostic users: combination use of metformin/statins was associated with a 32% reduction in all-cause mortality (95% CI, 0.57-0.80), and 54% reduction in PCa mortality (95% CI, 0.30-0.69). No significant association of metformin alone was observed with either all-cause mortality or PCa mortality. CONCLUSIONS: Statin use alone or in combination with metformin was associated with lower all-cause and PCa mortality among high-risk patients, particularly in post-diagnostic settings; further studies are warranted.

Effect of Metformin and Statin Use on Survival in Pancreatic Cancer Patients: a Systematic Literature Review and Meta-analysis.

BACKGROUND AND OBJECTIVE: Current epidemiological studies report conflicting results for the effect of statin or metformin on pancreatic cancer overall survival. This literature review and meta-analysis summarize the studies reporting an association between statin or metformin use and overall survival of pancreatic cancer patients. METHODS: We systematically searched for studies about the association between statin or metformin use and pancreatic cancer overall survival in electronic databases (PubMed, ISI Web of Science, MEDLINE, Cochrane, Scopus, Google Scholar). A meta-analysis based on hazard ratios (HRs) and 95% confidence intervals (CIs) was performed using random effect models. Heterogeneity between the studies was examined using I2 statistics, and sensitivity analyses were conducted to assess the robustness of the findings. RESULTS: Of 116 statin-related articles identified, 6 retrospective cohort studies representing 12,057 patients were included. There was significant heterogeneity between studies. Statin use was associated with improved survival among pancreatic cancer patients (meta-HR = 0.75; 95% CI: 0.59, 0.90; P < 0.001). Of 311 metformin-related articles, 8 retrospective cohort studies and 2 randomized clinical trials, representing 3,042 patients were identified. Metformin use was associated with better overall survival among pancreatic cancer patients (meta-HR = 0.79; 95% CI: 0.70, 0.92, P < 0.001), and significant heterogeneity was observed between studies. CONCLUSION: Our findings suggest that the improved survival time of pancreatic cancer patients are associated with statin or metformin use. Due to the multiple sources of heterogeneity of the original studies, these findings should be considered cautiously, and confirmed with larger prospective individual-level studies.

Radiotherapy for Patients With Resected Tumor Deposit-Positive Colorectal Cancer: A Surveillance, Epidemiology, and End Results-Based Population Study.

CONTEXT: - According to the American Joint Committee on Cancer's Cancer Staging Manual, 7th edition, TNM classification, tumor deposit (TD)-positive colorectal cancers (CRCs) are classified as N1c. The effects of radiotherapy and the effects of the updated American Joint Committee on Cancer 7th edition TNM N1c classification for patients with TD-positive CRC are unclear. OBJECTIVE: - To investigate outcomes of radiotherapy in patients with resected TD-positive CRC. DESIGN: - Resected TD-positive CRCs diagnosed from 2010 to 2014 were identified in the Surveillance, Epidemiology, and End Results 18 database. Factors associated with overall survival (OS) and cancer-specific survival (CSS) were investigated using Kaplan-Meier and Cox proportional hazards models. RESULTS: - We included 2712 qualified CRC patients, who either underwent adjuvant radiotherapy (n = 187; 6.9%) or received no radiotherapy (n = 2525; 93.1%). Univariate Cox proportional models showed improved CSS among all CRC patients who underwent adjuvant radiotherapy (CSS hazard ratio, 0.73; 95% CI, 0.57-0.95) and among rectal cancer patients when separated by location (hazard ratio, 0.57; 95% CI, 0.40-0.83), although these associations were attenuated in multivariable-adjusted models. There was improved OS among rectal cancer patients (hazard ratio, 0.77; 95% CI, 0.59-0.99). In subgroup analyses, radiotherapy was not associated with OS or CSS in either metastatic or nonmetastatic CRC patients. Instead, N1c category (versus N0) was associated with a worse OS (hazard ratio, 1.43; 95% CI, 1.31-1.57) but was not associated with CSS. CONCLUSIONS: - Radiotherapy did not independently improve OS among TD-positive CRC patients. In this study, classifying TD positivity as N1c was associated with worse OS than classifying TD positivity as N0. The findings seem to challenge the benefits of radiotherapy and the new N1c classification of TD for TD-positive CRC patients.

Differential and Joint Effects of Metformin and Statins on Overall Survival of Elderly Patients with Pancreatic Adenocarcinoma: A Large Population-Based Study.

Background: Published evidence indicates that individual use of metformin and statin is associated with reduced cancer mortality. However, their differential and joint effects on pancreatic cancer survival are inconclusive.Methods: We identified a large population-based cohort of 12,572 patients ages 65 years or older with primary pancreatic ductal adenocarcinoma (PDAC) diagnosed between 2008 and 2011 from the Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked database. Exposure to metformin and statins was ascertained from Medicare Prescription Drug Event files. Cox proportional hazards models with time-varying covariates adjusted for propensity scores were used to assess the association while controlling for potential confounders.Results: Of 12,572 PDAC patients, 950 (7.56%) had used metformin alone, 4,506 (35.84%) had used statin alone, and 2,445 (19.45%) were dual users. Statin use was significantly associated with improved overall survival [HR, 0.94; 95% confidence interval (CI), 0.90-0.98], and survival was more pronounced in postdiagnosis statin users (HR, 0.69; 95% CI, 0.56-0.86). Metformin use was not significantly associated with overall survival (HR, 1.01; 95% CI, 0.94-1.09). No beneficial effect was observed for dual users (HR, 1.00; 95% CI, 0.95-1.05).Conclusions: Our findings suggest potential benefits of statins on improving survival among elderly PDAC patients; further prospective studies are warranted to corroborate the putative benefit of statin therapy in pancreatic cancer.Impact: Although more studies are needed to confirm our findings, our data add to the body of evidence on potential anticancer effects of statins. Cancer Epidemiol Biomarkers Prev; 26(8); 1225-32. ©2017 AACR.

Weakening Impact of Excessive Human Serum Albumin (eHSA) on Cisplatin and Etoposide Anticancer Effect in C57BL/6 Mice with Tumor and in Human NSCLC A549 Cells.

Excessive human serum albumin (eHSA) impact on anticancer effects is inconsistent. We explored the outcome of cisplatin (DDP)/etoposide (VP-16) plus eHSA in vivo and in vitro. C57BL/6 mice with tumor were used to compare the efficacy of DDP/VP-16 alone and DDP/VP-16+eHSA. Blood albumin was measured to confirm whether eHSA elevate its level. Western blotting assay were used to measure the expression of ERCC1/TOP2A in tumor tissues. Cell proliferation, mRNA, and protein expression of ERCC1/TOP2A were also assayed to compare two groups in A549 cells. Furthermore we evaluated eHSA impact on cell proliferation in RNAi targeting ERCC1/TOP2A in A549 cells, respectively. eHSA reduced the anticancer effect of DDP/VP-16 without altering albumin level, increased protein expression of ERCC1/TOP2A, respectively in mice. Similarly, eHSA increased mRNA and proteins expression of ERCC1/TOP2A in A549 cells. In RNAi A549 cells, however, eHSA no longer weakened but enhanced the anticancer effect of DDP, while no longer altered the effect of VP-16. Our findings suggested that eHSA weaken the anticancer effect of DDP/VP-16 via up-regulating ERCC1/TOP2A expression, respectively. Further molecular mechanism studies are warranted to investigate whether eHSA is not conducive to lung cancer chemotherapy.

In vitro comparative studies of resveratrol and triacetylresveratrol on cell proliferation, apoptosis, and STAT3 and NFκB signaling in pancreatic cancer cells.

Resveratrol (RES) has been studied extensively as an anticancer agent. However, the anticancer effects of triacetylresveratrol (TRES, an acetylated analog of RES) which has higher bioavailability have not been well established. We comparatively evaluated their effects on cell proliferation, apoptosis and the molecular changes in STAT3, NFκB and apoptotic signaling pathways in pancreatic cancer cells. Apoptosis was determined by flow cytometry. The nuclear translocation and interaction of STAT3 and NFκB were detected by Western blotting and immunoprecipitation, respectively. Both TRES and RES inhibited cell viability, and induced apoptosis of pancreatic cancer cells in a concentration and incubation time-dependent manner. TRES, similarly to RES, inhibited the phosphorylation of STAT3 and NFκB, down-regulated Mcl-1, and up-regulated Bim and Puma in pancreatic cancer cells. Remarkably, we, for the first time, observed that both TRES and RES suppressed the nuclear translocation, and interrupted the interaction of STAT3 and NFκB in PANC-1 cells. Comparative anticancer effects of TRES and RES on pancreatic cancer suggested that TRES with higher bioavailability may be a potential agent for pancreatic cancer prevention and treatment. Further in vivo experiments and functional studies are warranted to investigate whether TRES exhibits better beneficial effects than RES in mice and humans.

Targeting tumor-associated macrophages to combat pancreatic cancer.

The tumor microenvironment is replete with cells that evolve with and provide support to tumor cells during the transition to malignancy. The hijacking of the immune system in the pancreatic tumor microenvironment is suggested to contribute to the failure to date to produce significant improvements in pancreatic cancer survival by various chemotherapeutics. Regulatory T cells, myeloid derived suppressor cells, and fibroblasts, all of which constitute a complex ecology microenvironment, can suppress CD8+ T cells and NK cells, thus inhibiting effector immune responses. Tumor-associated macrophages (TAM) are versatile immune cells that can express different functional programs in response to stimuli in tumor microenvironment at different stages of pancreatic cancer development. TAM have been implicated in suppression of anti-tumorigenic immune responses, promotion of cancer cell proliferation, stimulation of tumor angiogenesis and extracellular matrix breakdown, and subsequent enhancement of tumor invasion and metastasis. Many emerging agents that have demonstrated efficacy in combating other types of tumors via modulation of macrophages in tumor microenvironments are, however, only marginally studied for pancreatic cancer prevention and treatment. A better understanding of the paradoxical roles of TAM in pancreatic cancer may pave the way to novel preventive and therapeutic approaches. Here we give an overview of the recruitment and differentiation of macrophages, TAM and pancreatic cancer progression and prognosis, as well as the potential preventive and therapeutic targets that interact with TAM for pancreatic cancer prevention and treatment.

Metformin pharmacogenomics: a genome-wide association study to identify genetic and epigenetic biomarkers involved in metformin anticancer response using human lymphoblastoid cell lines.

Metformin is currently considered as a promising anticancer agent in addition to its anti-diabetic effect. To better individualize metformin therapy and explore novel molecular mechanisms in cancer treatment, we conducted a pharmacogenomic study using 266 lymphoblastoid cell lines (LCLs). Metformin cytotoxicity assay was performed using the MTS assay. Genome-wide association (GWA) analyses were performed in LCLs using 1.3 million SNPs, 485k DNA methylation probes, 54k mRNA expression probe sets, and metformin cytotoxicity (IC50s). Top candidate genes were functionally validated using siRNA screening, followed by MTS assay in breast cancer cell lines. Further study of one top candidate, STUB1, was performed to elucidate the mechanisms by which STUB1 might contribute to metformin action. GWA analyses in LCLs identified 198 mRNA expression probe sets, 12 SNP loci, and 5 DNA methylation loci associated with metformin IC50 with P-values <10−4 or <10−5. Integrated SNP/methylation loci-expression-IC50 analyses found 3 SNP loci or 5 DNA methylation loci associated with metformin IC50 through trans-regulation of expression of 11 or 26 genes with P-value <10−4. Functional validation of top 61 candidate genes in 4 IPA networks indicated down regulation of 14 genes significantly altered metformin sensitivity in two breast cancer cell lines. Mechanistic studies revealed that the E3 ubiquitin ligase, STUB1, could influence metformin response by facilitating proteasome-mediated degradation of cyclin A. GWAS using a genomic data-enriched LCL model system, together with functional and mechanistic studies using cancer cell lines, help us to identify novel genetic and epigenetic biomarkers involved in metformin anticancer response.

Transcriptomic analysis of pancreatic cancer cells in response to metformin and aspirin: an implication of synergy.

Metformin and aspirin have been studied extensively as cancer preventative and therapeutic agents. However, the underlying molecular mechanisms for the inhibitory effects of pancreatic cancer development remain undefined. To gain further insight into their biological function in pancreatic cancer, we conducted a transcriptomic analysis using RNA sequencing to assess the differential gene expression induced by metformin (5 mM) and aspirin (2 mM), alone or in combination, after treatment of PANC-1 cells for 48 hours. Compared to an untreated control, metformin down-regulated 58 genes and up-regulated 91 genes, aspirin down-regulated 12 genes only, while metformin plus aspirin down-regulated 656 genes and up-regulated 449 genes (fold-change > 2, P < 10(-5)). Of the top 10 genes (fold-change > 10, P < 10(-10)) regulated by metformin plus aspirin, PCDH18, CCL2, RASL11A, FAM111B and BMP5 were down-regulated ≥ 20-fold, while NGFR, NPTX1, C7orf57, MRPL23AS1 and UNC5B were up-regulated ≥ 10-fold. Ingenuity Pathway Analysis (IPA) revealed that the pathways, "cholesterol biosynthesis", "cell cycle: G1/S checkpoint regulation", and "axonal guidance signaling" were the most statistically significant pathways modulated by metformin plus aspirin. Although the results need further functional validation, these data provide the first evidence for the synergistic action between metformin and aspirin in modulating the transcriptional profile of pancreatic cancer cells.

Gene-by-Environment Interactions in Pancreatic Cancer: Implications for Prevention.

Pancreatic cancer (PC) has been estimated to have higher incidence and correspondingly higher mortality rates in more developed regions worldwide. Overall, the age-adjusted incidence rate is 4.9/10(5) and age-adjusted mortality rate is at 4.8/10(5). We review here our current knowledge of modifiable risk factors (cigarette smoking, obesity, diet, and alcohol) for PC, genetic variants implicated by genome-wide association studies, possible genetic interactions with risk factors, and prevention strategies to provide future research directions that may further our understanding of this complex disease. Cigarette smoking is consistently associated with a two-fold increased PC risk. PC associations with dietary intake have been largely inconsistent, with the potential exception of certain unsaturated fatty acids decreasing risk and well-done red meat or meat mutagens increasing risk. There is strong evidence to support that obesity (and related measures) increase risk of PC. Only the heaviest alcohol drinkers seem to be at an increased risk of PC. Currently, key prevention strategies include avoiding tobacco and excessive alcohol consumption and adopting a healthy lifestyle. Screening technologies and PC chemoprevention are likely to become more sophisticated, but may only apply to those at high risk. Risk stratification may be improved by taking into account gene environment interactions. Research on these modifiable risk factors is key to reducing the incidence of PC and understanding who in the population can be considered high risk.

Metformin combined with aspirin significantly inhibit pancreatic cancer cell growth in vitro and in vivo by suppressing anti-apoptotic proteins Mcl-1 and Bcl-2.

Metformin and aspirin have been studied extensively as cancer preventive or therapeutic agents. However, the effects of their combination on pancreatic cancer cells have not been investigated. Herein, we evaluated the effects of metformin and aspirin, alone or in combination, on cell viability, migration, and apoptosis as well as the molecular changes in mTOR, STAT3 and apoptotic signaling pathways in PANC-1 and BxPC3 cells. Metformin and aspirin, at relatively low concentrations, demonstrated synergistically inhibitory effects on cell viability. Compared to the untreated control or individual drug, the combination of metformin and aspirin significantly inhibited cell migration and colony formation of both PANC-1 and BxPC-3 cells. Metformin combined with aspirin significantly inhibited the phosphorylation of mTOR and STAT3, and induced apoptosis as measured by caspase-3 and PARP cleavage. Remarkably, metformin combined with aspirin significantly downregulated the anti-apoptotic proteins Mcl-1 and Bcl-2, and upregulated the pro-apoptotic proteins Bim and Puma, as well as interrupted their interactions. The downregulation of Mcl-1 and Bcl-2 was independent of AMPK or STAT3 pathway but partially through mTOR signaling and proteasome degradation. In a PANC-1 xenograft mouse model, we demonstrated that the combination of metformin and aspirin significantly inhibited tumor growth and downregulated the protein expression of Mcl-1 and Bcl-2 in tumors. Taken together, the combination of metformin and aspirin significantly inhibited pancreatic cancer cell growth in vitro and in vivo by regulating the pro- and anti-apoptotic Bcl-2 family members, supporting the continued investigation of this two drug combination as chemopreventive or chemotherapeutic agents for pancreatic cancer.

Metformin suppresses pancreatic tumor growth with inhibition of NFκB/STAT3 inflammatory signaling.

OBJECTIVES: To further elucidate the anticancer mechanisms of metformin against pancreatic cancer, we evaluated the inhibitory effects of metformin on pancreatic tumorigenesis in a genetically engineered mouse model and investigated its possible anti-inflammatory and antiangiogenesis effects. METHODS: Six-week-old LSL-Kras;Trp53 mice (10 per group) were administered once daily intraperitoneally with saline (control) for 1 week or metformin (125 mg/kg) for 1 week (Met_1wk) or 3 weeks (Met_3wk) before tumor initiation. All mice continued with their respective injections for 6 weeks after tumor initiation. Molecular changes were evaluated through quantitative polymerase chain reaction, immunohistochemistry, and Western blotting. RESULTS: At euthanasia, pancreatic tumor volume in the Met_1wk (median, 181.8 mm) and Met_3wk (median, 137.9 mm) groups was significantly lower than those in the control group (median, 481.1 mm; P = 0.001 and 0.0009, respectively). No significant difference was observed between the Met_1wk and Met_3wk groups (P = 0.51). These results were further confirmed using tumor weight and tumor burden measurements. Furthermore, metformin treatment decreased the phosphorylation of nuclear factor κB and signal transducer and activator of transcription 3 as well as the expression of specificity protein 1 transcription factor and several nuclear factor κB-regulated genes. CONCLUSIONS: Metformin may inhibit pancreatic tumorigenesis by modulating multiple molecular targets in inflammatory pathways.

Repurposing of metformin and aspirin by targeting AMPK-mTOR and inflammation for pancreatic cancer prevention and treatment.

Pancreatic cancer, as the fourth leading cause of cancer-related deaths, carries a poor prognosis with a median survival of 6 months and a dismal 5-year survival rate of 3% to 5%. These statistics highlight an urgent need for novel chemopreventive and therapeutic strategies for this malignancy. Metformin and aspirin have been explored as two emerging cancer chemoprevention agents for different types of cancers, including pancreatic cancer. Here, we review the effects of both metformin and aspirin on pancreatic tumorigenesis and their potential actions in pancreatic cancer. Special attention is paid to their effects on the important signaling pathways of pancreatic cancer development as well as possible mechanisms for synergy between these two agents. For metformin, the most important mechanism may involve the inhibition of mTOR signaling via AMP-activated protein kinase (AMPK)-dependent and -independent pathways. For aspirin, the major mechanism is the anti-inflammatory action through the inhibition of COX-1/COX-2 and modulation of the NFκB or STAT3 pathway. In addition, aspirin may activate AMPK, and both agents may affect Notch, Wnt/ß-catenin, and other signaling pathways. The combination of metformin and aspirin will provide additive and possibly synergistic effects for the prevention and treatment of pancreatic cancer.

Integrative gene set analysis: application to platinum pharmacogenomics.

Integrative genomics has the potential to uncover relevant loci, as clinical outcome and response to chemotherapies are most likely not due to a single gene (or data type) but rather a complex relationship involving genetic variation, mRNA, DNA methylation, and copy number variation. In addition to this complexity, many complex phenotypes are thought to be controlled by the interplay of multiple genes within the same molecular pathway or gene set (GS). To address these two challenges, we propose an integrative gene set analysis approach and apply this strategy to a cisplatin (CDDP) pharmacogenomics study involving lymphoblastoid cell lines for which genome-wide SNP and mRNA expression data was collected. Application of the integrative GS analysis implicated the role of the RNA binding and cytoskeletal part GSs. The genes LMNB1 and CENPF, within the cytoskeletal part GS, were functionally validated with siRNA knockdown experiments, where the knockdown of LMNB1 and CENPF resulted in CDDP resistance in multiple cancer cell lines. This study demonstrates the utility of an integrative GS analysis strategy for detecting novel genes associated with response to cancer therapies, moving closer to tailored therapy decisions for cancer patients.

Polymorphisms in metabolism/antioxidant genes may mediate the effect of dietary intake on pancreatic cancer risk.

OBJECTIVES: A source of variation for inconsistent dietary-pancreatic cancer associations may be individuals carrying constitutional metabolism/antioxidant gene variants that differentially benefit compared to homozygous individuals. Seventy-six tag single-nucleotide polymorphisms were genotyped in 13 candidate genes to test differential associations with pancreatic adenocarcinoma. METHODS: A clinic-based case-control design was used to rapidly ascertain 251 cases and 970 frequency matched controls who provided blood samples and completed a 144-item food frequency questionnaire. Single-nucleotide polymorphisms were evaluated using a dominant genetic model and dietary categories split on controls' median intake. Logistic regression was used to calculate odds ratios and 95% confidence intervals, adjusted for potential confounders. RESULTS: Significant increased associations (Bonferroni corrected P ≤ 0.0007) were observed for carriers of greater than or equal to 1 minor allele for rs3816257 (glucosidase, α; acid [GAA]) and lower intake of deep-yellow vegetables (1.90 [1.28-2.83]); and carriers of no minor allele for rs12807961 (catalase [CAT]) and high total grains intake (2.48 [1.50-4.09]), whereas those with greater than or equal to 1 minor allele had a decreasing slope (across grains). The reference group was no minor alleles with low dietary intake. CONCLUSIONS: Interindividual variation in metabolism/antioxidant genes could interact with dietary intake to influence pancreatic cancer risk.

High-throughput library screening identifies two novel NQO1 inducers in human lung cells.

Many phytochemicals possess antioxidant and cancer-preventive properties, some putatively through antioxidant response element-mediated phase II metabolism, entailing mutagen/oxidant quenching. In our recent studies, however, most candidate phytochemical agents were not potent in inducing phase II genes in normal human lung cells. In this study, we applied a messenger RNA (mRNA)-specific gene expression-based high throughput in vitro screening approach to discover new, potent plant-derived phase II inducing chemopreventive agents. Primary normal human bronchial epithelial (NHBE) cells and immortalized human bronchial epithelial cells (HBECs) were exposed to 800 individual compounds in the MicroSource Natural Products Library. At a level achievable in humans by diet (1.0 µM), 2,3-dihydroxy-4-methoxy-4'-ethoxybenzophenone (DMEBP), triacetylresveratrol (TRES), ivermectin, sanguinarine sulfate, and daunorubicin induced reduced nicotinamide adenine dinucleotide phosphate:quinone oxidoreductase 1 (NQO1) mRNA and protein expression in NHBE cells. DMEBP and TRES were the most attractive agents as coupling potency and low toxicity for induction of NQO1 (mRNA level, ≥3- to 10.8-fold that of control; protein level, ≥ two- to fourfold that of control). Induction of glutathione S-transferase pi mRNA expression was modest, and none was apparent for glutathione S-transferase pi protein expression. Measurements of reactive oxygen species and glutathione/oxidized glutathione ratio showed an antioxidant effect for DMEBP, but no definite effect was found for TRES in NHBE cells. Exposure of NHBE cells to H(2)O(2) induced nuclear translocation of nuclear factor erythroid 2-related factor 2, but this translocation was not significantly inhibited by TRES and DMEBP. These studies show that potency and low toxicity may align for two potential NQO1-inducing agents, DMEBP and TRES.