Regulation of hypoxia-inducible factor-1alpha, vascular endothelial growth factor, and angiogenesis by an insulin-like growth factor-I receptor autocrine loop in human pancreatic cancer

Pancreatic Cancer: A Review of Risk Factors

Pancreatic adenocarcinoma is one of the most lethal types of gastrointestinal cancer despite the latest medical advances. Its incidence has continuously increased in recent years in developed countries. The location of the pancreas can result in the initial symptoms of neoplasia being overlooked, which can lead to a delayed diagnosis and a subsequent reduction in the spectrum of available therapeutic options. The role of modifiable risk factors in pancreatic cancer has been extensively studied in recent years, with smoking and alcohol consumption identified as key contributors. However, the few screening programs that have been developed focus exclusively on genetic factors, without considering the potential impact of modifiable factors on disease occurrence. Thus, fully understanding and detecting the risk factors for pancreatic cancer represents an important step in the prevention and early diagnosis of this type of neoplasia. This review reports the available evidence on different risk factors and identifies the areas that could benefit the most from additional studies.

A hierarchical prognostic model for Co-diabetes pancreatic adenocarcinoma

Background

Co-diabetes pancreatic adenocarcinoma has a poorer prognosis than pancreatic adenocarcinoma without diabetes. This study aimed to develop a reliable prognostic model for patients with co-diabetes pancreatic adenocarcinoma.

Method

Overall, 169 patients with co-diabetes pancreatic adenocarcinoma were included in our study. First, the independent risk factors affecting the prognosis of patients with co-diabetes pancreatic adenocarcinoma were determined by univariate and multivariate Cox regression analyses. Based on these identified risk factors, we developed a nomogram and evaluated its predictive ability using the concordance index, receiver operating characteristic curve, calibration plot, decision curve, and net reclassification index.

Results

In this study, prealbumin, transferrin, carcinoembryonic antigen, distant metastasis, tumor differentiation neutrophil count, lymphocyte count and fasting blood glucose were confirmed as significant prognostic factors. Based on these predictors, a new nomogram was developed. Compared with the American Joint Committee on Cancer 8 staging system and other models, the nomogram achieved a higher concordance index in the training (0.795) and validation (0.729) queues. The area under the nomogram's curve for predicting patient survival at 0.5, 1, and 1.5 years in the training queue was >0.8. Patients were risk-stratified using the nomogram, and Kaplan-Meier survival curves of subgroups were plotted. The Kaplan-Meier curve also showed better separation than the American Joint Committee on Cancer 8 staging system, indicating that our model has a better risk hierarchical ability.

Conclusions

Compared to the American Joint Committee on Cancer 8 staging system and other predictive models, our model showed better predictive ability for patients with co-diabetes pancreatic adenocarcinoma. Our model will help in patients' risk stratification and improves their prognosis.

Hypoxia-induced factor and its role in liver fibrosis

Liver fibrosis develops as a result of severe liver damage and is considered a major clinical concern throughout the world. Many factors are crucial for liver fibrosis progression. While advancements have been made to understand this disease, no effective pharmacological drug and treatment strategies have been established that can effectively prevent liver fibrosis or even could halt the fibrotic process. Most of those advances in curing liver fibrosis have been aimed towards mitigating the causes of fibrosis, including the development of potent antivirals to inhibit the hepatitis virus. It is not practicable for many individuals; however, a liver transplant becomes the only suitable alternative. A liver transplant is an expensive procedure. Thus, there is a significant need to identify potential targets of liver fibrosis and the development of such agents that can effectively treat or reverse liver fibrosis by targeting them. Researchers have identified hypoxia-inducible factors (HIFs) in the last 16 years as important transcription factors driving several facets of liver fibrosis, making them possible therapeutic targets. The latest knowledge on HIFs and their possible role in liver fibrosis, along with the cell-specific activities of such transcription factors that how they play role in liver fibrosis progression, is discussed in this review.

Hypoxia‐induced ELF3 promotes tumor angiogenesis through IGF1/IGF1R

Epithelial ovarian cancer (EOC) is one of the most lethal gynecological cancers despite a relatively low incidence. Angiogenesis, one of the hallmarks of cancer, is essential for the pathogenesis of EOC, which is related to the induction of angiogenic factors. We found that ELF3 was highly expressed in EOCs under hypoxia and functioned as a transcription factor for IGF1. The ELF3‐mediated increase in the secretion of IGF1 and VEGF promoted endothelial cell proliferation, migration, and EOC angiogenesis. Although this situation was much exaggerated under hypoxia, ELF3 silencing under hypoxia significantly attenuated angiogenic activity in endothelial cells by reducing the expression and secretion of IGF1 and VEGF. ELF3 silencing attenuated angiogenesis and tumorigenesis in ex vivo and xenograft mouse models. Consequently, ELF3 plays an important role in the induction of angiogenesis and tumorigenesis in EOC as a transcription factor of IGF1. A detailed understanding of the biological mechanism of ELF3 may both improve current antiangiogenic therapies and have anticancer effects for EOC.

The Intricate Crosstalk Between Insulin and Pancreatic Ductal Adenocarcinoma: A Review From Clinical to Molecular

Increased insulin level (or "hyperinsulinemia") is a common phenomenon in pancreatic ductal adenocarcinoma (PDA) patients and signals poor clinical outcomes. Insulin is safe in low PDA risk population, while insulin significantly promotes PDA risk in high PDA risk population. The correlation between insulin and PDA is a reciprocal self-reinforcing relationship. On the one hand, pancreatic cancer cells synthesize multiple molecules to cause elevated peripheral insulin resistance, thus enhancing hyperinsulinemia. On the other hand, insulin promotes pancreatic cancer initiation and sustains PDA development by eliciting tumorigenic inflammation, regulating lipid and glucose metabolic reprogram, overcoming apoptosis through the crosstalk with IGF-1, stimulating cancer metastasis, and activating tumor microenvironment formation (inflammation, fibrosis, and angiogenesis). Currently, taking glucose sensitizing agents, including metformin, SGLT-2 inhibitor, and GLP-1 agonist, is an effective way of lowering insulin levels and controlling PDA development at the same time. In the future, new drugs targeting insulin-related signal pathways may pave a novel way for suppressing PDA initiation and progression.

Chronic atrophic gastritis and intestinal metaplasia induced by high-salt and N-methyl-N'-nitro-N-nitrosoguanidine intake in rats

The aim of the present study was to induce chronic atrophic gastritis (CAG) with intestinal metaplasia (IM) in rats by administering saturated salt and methyl-N'-nitro-N-nitrosoguanidine (MNNG) via oral gavage. Changes in gastric mucosal blood microcirculation and activation of the cyclo-oxygenase-2 (COX-2)/hypoxia inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF) signaling pathway during CAG and IM development were investigated. After administering saturated salt and MNNG for 25 weeks, mild atrophy was detected in the stomach of model rats using hematoxylin and eosin staining. CAG with IM was successfully induced in the gastric mucosa of the model rats after 35 weeks. Gastric mucosal blood flow was decreased in comparison with controls as early as 15 weeks after treatment to induce CAG and the mRNA expression levels of COX-2, HIF-1α, vascular endothelial growth factor receptor (VEGFR)1 and VEGFR2 were increased in comparison with untreated rats as early as 25 weeks after treatment. HIF-1α, COX-2 and VEGFR2 expression levels were increased as early as 25 weeks after CAG induction treatment when compared to controls and HIF-1α, COX-2, VEGFR1 and VEGFR2 expression levels were significantly increased after 35 weeks. These findings indicated that administering saturated salt and MNNG by gavage for 35 weeks successfully induced CAG and IM in rats. Furthermore, the microcirculation was disturbed before activation of the COX-2/HIF-1α/VEGF signaling pathway.

The role of hypoxia in the tumor microenvironment and development of cancer stem cell: a novel approach to developing treatment

Hypoxia is a common feature of solid tumors, and develops because of the rapid growth of the tumor that outstrips the oxygen supply, and impaired blood flow due to the formation of abnormal blood vessels supplying the tumor. It has been reported that tumor hypoxia can: activate angiogenesis, thereby enhancing invasiveness and risk of metastasis; increase survival of tumor, as well as suppress anti-tumor immunity and hamper the therapeutic response. Hypoxia mediates these effects by several potential mechanisms: altering gene expression, the activation of oncogenes, inactivation of suppressor genes, reducing genomic stability and clonal selection. We have reviewed the effects of hypoxia on tumor biology and the possible strategiesto manage the hypoxic tumor microenvironment (TME), highlighting the potential use of cancer stem cells in tumor treatment.

Glycemic Status, Insulin Resistance, and Risk of Pancreatic Cancer Mortality in Individuals With and Without Diabetes

INTRODUCTION

The impact of glycemic status and insulin resistance on the risk of pancreatic cancer in the nondiabetic population remains uncertain. We aimed to examine the association of glycemic status and insulin resistance with pancreatic cancer mortality in individuals with and without diabetes.

METHODS

This is a cohort study of 572,021 Korean adults without cancer at baseline, who participated in repeat screening examinations which included fasting blood glucose, hemoglobin A1c, and insulin, and were followed for a median of 8.4 years (interquartile range, 5.3 -13.2 years). Vital status and pancreatic cancer mortality were ascertained through linkage to national death records.

RESULTS

During 5,211,294 person-years of follow-up, 260 deaths from pancreatic cancer were identified, with a mortality rate of 5.0 per 10 person-years. In the overall population, the risk of pancreatic cancer mortality increased with increasing levels of glucose and hemoglobin A1c in a dose-response manner, and this association was observed even in individuals without diabetes. In nondiabetic individuals without previously diagnosed or screen-detected diabetes, insulin resistance and hyperinsulinemia were positively associated with increased pancreatic cancer mortality. Specifically, the multivariable-adjusted hazard ratio (95% confidence intervals) for pancreatic cancer mortality comparing the homeostatic model assessment of insulin resistance ≥75th percentile to the <75th percentile was 1.49 (1.08-2.05), and the corresponding hazard ratio comparing the insulin ≥75th percentile to the <75th percentile was 1.43 (1.05-1.95). These associations remained significant when introducing changes in insulin resistance, hyperinsulinemia, and other confounders during follow-up as time-varying covariates.

DISCUSSION

Glycemic status, insulin resistance, and hyperinsulinemia, even in individuals without diabetes, were independently associated with an increased risk of pancreatic cancer mortality.

B-cell epitope peptide cancer vaccines: a new paradigm for combination immunotherapies with novel checkpoint peptide vaccine

In light of the numerous US FDA-approved humanized monoclonal antibodies (mAbs) for cancer immunotherapy, it is surprising that the advancement of B-cell epitope vaccines designed to elicit a natural humoral polyclonal antibody response has not gained traction in the immune-oncology landscape. Passive immunotherapy with humanized mAbs (Trastuzumab [Herceptin®]; Pertuzumab [Perjeta®]) has provided clinical benefit to breast cancer patients, albeit with significant shortcomings including toxicity problems and resistance, high costs, sophisticated therapeutic regimen and long half-life. The role of B-cell humoral immunity in cancer is under appreciated and underdeveloped. We have advanced the idea of active immunotherapy with chimeric B-cell epitope peptides incorporating a 'promiscuous' T-cell epitope that elicits a polyclonal antibody response, which provides safe, cost-effective therapeutic advantage over mAbs. We have created a portfolio of validated B-cell peptide epitopes against multiple receptor tyrosine kinases (HER-1, HER-3, IGF-1R and VEGF). We have successfully translated two HER-2 combination B-cell peptide vaccines in Phase I and II clinical trials. We have recently developed an effective novel PD-1 vaccine. In this article, I will review our approaches and strategies that focus on B-cell epitope cancer vaccines.

The IGF-II-Insulin Receptor Isoform-A Autocrine Signal in Cancer: Actionable Perspectives

Insulin receptor overexpression is a common event in human cancer. Its overexpression is associated with a relative increase in the expression of its isoform A (IR^A), a shorter variant lacking 11 aa in the extracellular domain, conferring high affinity for the binding of IGF-II along with added intracellular signaling specificity for this ligand. Since IGF-II is secreted by the vast majority of malignant solid cancers, where it establishes autocrine stimuli, the co-expression of IGF-II and IR^A in cancer provides specific advantages such as apoptosis escape, growth, and proliferation to those cancers bearing such a co-expression pattern. However, little is known about the exact role of this autocrine ligand–receptor system in sustaining cancer malignant features such as angiogenesis, invasion, and metastasis. The recent finding that the overexpression of angiogenic receptor kinase EphB4 along with VEGF-A is tightly dependent on the IGF-II/IR^A autocrine system independently of IGFIR provided new perspectives for all malignant IGF2omas (those aggressive solid cancers secreting IGF-II). The present review provides an updated view of the IGF system in cancer, focusing on the biology of the autocrine IGF-II/IR^A ligand–receptor axis and supporting its underscored role as a malignant-switch checkpoint target.

Expression of Breast Cancer-Related Epitopes Targeting the IGF-1 Receptor in Chimeric Human Parvovirus B19 Virus-Like Particles

Breast cancer is a worldwide health problem, and the complexity of the disease, as well as the lack of treatment specificity, generates an urgent need for developing prophylactic and therapeutic measures. Searching for novel epitope-based approaches able to induce tumour immunity, we designed virus-like particles (VLPs) derived from Human parvovirus B19 assembled of chimeric VP2 proteins displaying two epitopes from the insulin-like growth factor-1 receptor (IGF-1R). Here, we present the generation of two chimeric VP2s that retain the stability, solubility and conditions of purification and assembly of the native VP2. We generated versatile chimeric multiepitope anti-cancer vaccine candidates, which prevented and delayed tumour growth when used in a prophylactic scheme of 4 weekly immunizations prior to 4T1 cell inoculation in female BALB/c mice. The presence of specific antibodies against the displayed epitopes suggests their participation in the protective effect; in contrast, no significant proliferative T-cell responses were recorded following stimulation by specific epitopes. The results comprise an approach whereby fusing desired epitopes from cancer to the N-terminus of B19 VP2 protein can generate a library of chimeric VP2-desired epitopes for further assembly in a designed and personalized epitope delivery system.

Diabetes and its Potential Impact on Head and Neck Oncogenesis

In recent years, the incidence of diabetes mellitus and cancer has increased sharply; indeed, these have become the two most important diseases threatening health and survival. Head and neck (HN) tumors are the sixth most common malignancies in humans. Numerous studies have shown that there are many common risk factors for diabetes mellitus and HN squamous cell carcinoma, including advanced age, poor diet and lifestyle, and environmental factors. However, the mechanism linking the two diseases has not been identified. A number of studies have shown that diabetes affects the development, metastasis, and prognosis of HN cancer, potentially through the associated hyperglycemia, hyperinsulinemia and insulin resistance, or chronic inflammation. More recent studies show that metformin, the first-line drug for the treatment of type 2 diabetes, can significantly reduce the risk of HN tumor development and reduce mortality in diabetic patients. Here, we review recent progress in the study of the relationship between diabetes mellitus and HN carcinogenesis, and its potential mechanisms, in order to provide a scientific basis for the early diagnosis and effective treatment of these diseases.

Weiqi Decoction Attenuated Chronic Atrophic Gastritis with Precancerous Lesion through Regulating Microcirculation Disturbance and HIF-1α Signaling Pathway

Aim

Chronic atrophic gastritis (CAG), the precancerous lesions of gastric cancer, plays an important role in the stepwise process of gastric cancer. The ancient Chinese medicine believes in that Qi deficiency and blood stasis are involved in the pathogenesis of CAG. Weiqi decoction, a classical formula from Longhua Hospital, could supplement Qi and activate blood circulation of human beings and has been used for treating CAG in clinic over twenty years. The study aims to clarify the effect and underlying molecular mechanism of Weiqi decoction on CAG rats.

Methods

Forty-eight male Wistar rats were divided randomly into six groups: control group, model group, folic acid group, and WQD-treated groups at doses of 4 g/kg, 2 g/kg, and 1 g/kg, with eight rats in each group. MNNG and saturated NaCl were used to induce CAG rat with precancerous lesion (intestinal metaplasia and dysplasia). After 40 weeks, gastric mucosal blood flow was measured using Laser Doppler Flowmetry. The pathological changes of the gastric mucosa were identified by H&E staining and AB-PAS staining. The protein expression of COX-2, HIF-1α, VEGFR1, VEGFR2, Ki67, and cleaved caspase 3 in the gastric tissues was measured by western blotting approach. Gene expression of COX-2, HIF-1α, VEGF, VEGFR1, VEGFR2, Ang-1, and Ang-2 was detected by using Quantitative PCR method. The PGE2 concentrations in serum were detected by ELISA method. The protein expression of Ki67 in gastric mucosa was also detected by immunohistochemistry.

Results

Compared with control rats, atrophy and intestinal metaplasia as well as the microcirculation disturbance of gastric mucosa were induced in the stomach of CAG rats identified by the H&E and AB-PAS staining as well as microcirculation measurement, which could be significantly attenuated by WQD treatment. Moreover, compared with the control group, the protein and gene expression of COX-2, HIF-1α, VEGFR1, and VEGFR2 in gastric tissues of pylorus was obviously increased and the serum PGE2 level was significantly deceased in CAG rats, which could be significantly counteracted by WQD administration. However, the gene expression of Ang-1 and Ang-2 was not significant difference between control rats and CAG rats, and WQD also had no significant effect on the gene expression of Ang-1 and Ang-2. Furthermore, the increased cell proliferation marked by upregulated protein expression of Ki67 and decreased cell apoptosis marked by downregulated protein expression of cleaved caspase 3 in stomach of pylorus in CAG rats were obviously reversed by WQD treatment.

Conclusion

WQD attenuated CAG with precancerous lesion through regulating gastric mucosal blood flow disturbance and HIF-1α signaling pathway.

Exploring the relationship between nonalcoholic fatty liver disease and pancreatic cancer by computed tomographic survey

Pancreatic cancer is difficult to diagnose in an early stage, and has the highest mortality of all types of cancer. Obesity, high body mass index, and increased abdominal girth are established risk factors. Some studies have postulated that there is a correlation between organ steatosis and pancreatic cancer. This study aims to explore whether nonalcoholic fatty liver disease (NAFLD) is a risk factor and a prognostic factor for pancreatic cancer. The study enrolled 557 patients (143 with and 414 without pancreatic cancer) who were diagnosed between January 2009 and December 2013. We reviewed the abdominal computed tomographic scans of the patients to confirm the diagnosis of NAFLD. Clinical parameters, laboratory data, and personal information were analyzed. NAFLD is an independent risk factor for pancreatic cancer according to adjusted multivariate logistic regression analysis (OR 2.63, 95% CI 1.24-5.58, p = 0.011). The Kaplan-Meier survival curve reveals that patients without NAFLD have longer survival than patients with NAFLD (p = 0.005, log-rank test). NAFLD is positively correlated with pancreatic cancer, a result suggesting that NAFLD may increase the incidence and risk of pancreatic cancer. Patients with pancreatic cancer and NAFLD have poorer overall survival than patients without NAFLD, perhaps, because dysregulated cytokine status leads to progression of pancreatic cancer. NAFLD may be a prognostic factor for pancreatic cancer.

Up-regulated basigin-2 in microglia induced by hypoxia promotes retinal angiogenesis

Retinal microglia cells contribute to vascular angiogenesis and vasculopathy induced by relative hypoxia. However, its concrete molecular mechanisms in shaping retinal angiogenesis have not been elucidated. Basigin, being involved in tumour neovasculogenesis, is explored to exert positive effects on retinal angiogenesis induced by microglia. Therefore, we set out to investigate the expression of basigin using a well-characterized mouse model of oxygen-induced retinopathy, which recapitulated hypoxia-induced aberrant neovessel growth. Our results elucidate that basigin is overexpressed in microglia, which accumulating in retinal angiogenic sprouts. In vitro, conditioned media from microglia BV2 under hypoxia treatment increase migration and tube formation of retinal capillary endothelia cells, compared with media from normoxic condition. The angiogenic capacity of BV2 is inhibited after basigin knockdown by small interfering RNAs. A new molecular mechanism for high angiogenic capacity, whereby microglia cells release basigin via up-regulation of PI3K-AKT and IGF-1 pathway to induce angiogenesis is unveiled. Collectively, our results demonstrate that basigin from hypoxic microglia plays a pivotal pro-angiogenic role, providing new insights into microglia-promoting retinal angiogenesis.

Pancreatic Cancer Heralded by Worsening Glycemic Control: A Report of Two Cases

Pancreatic ductal adenocarcinoma is the third leading cause of cancer-related death in the United States. Since it is usually diagnosed at an advanced stage, its prognosis remains poor. The initial presentation varies according to the tumor location. The most common presenting signs are weight loss, jaundice, and pain. Several epidemiological, clinical, and experimental studies over the past 2 decades have shown that long-standing diabetes is a modest risk factor for pancreatic cancer. However, new-onset diabetes has also been observed to be an early manifestation of pancreatic cancer. We report 2 cases where worsening glycemic control led to the diagnosis of pancreatic cancer.

Insulin-like growth factor (IGF) axis in cancerogenesis

Determination of the role of insulin-like growth factor (IGF) family components in carcinogenesis of several human tumors is based on numerous epidemiological and pre-clinical studies, experiments in vivo and in vitro and on attempts at application of drugs affecting the IGF axis. Investigative hypotheses in original studies were based on biological functions manifested by the entire family of IGF (ligands, receptors, linking proteins, adaptor molecules). In the context of carcinogenesis the most important functions of IGF family involve intensification of proliferation and inhibition of cell apoptosis and effect on cell transformation through synthesis of several regulatory proteins. IGF axis controls survival and influences on metastases of cells. Interactions of IGF axis components may be of a direct or indirect nature. The direct effects are linked to activation of PI3K/Akt signaling pathway, in which the initiating role is first of all played by IGF-1 and IGF-1R. Activity of this signaling pathway leads to an increased mitogenesis, cell cycle progression, and protection against different apoptotic stresses. Indirect effects of the axis depend on interactions between IGF and other molecules important for cancer etiology (e.g. sex hormones, products of suppressor genes, viruses, and other GFs) and the style of life (nutrition, physical activity). From the clinical point of view, components of IGF system are first of all considered as diagnostic serous and/or tissue biomarkers of a given cancer, prognostic factors and attractive target of modern anti-tumor therapies. Several mechanisms in which IGF system components act in the process of carcinogenesis need to be clarified, mainly due to multifactorial etiology of the neoplasms. Pin-pointing of the role played in carcinogenesis by any single signaling pathway remains particularly difficult. The aim of this review is to summarize the current data of several epidemiological studies, experiments in vitro and on animal models, to increase our understanding of the complex role of IGF family components in the most common human cancers.

A paradigm shift: Cancer therapy with peptide-based B-cell epitopes and peptide immunotherapeutics targeting multiple solid tumor types: Emerging concepts and validation of combination immunotherapy

There is a recognizable and urgent need to speed the development and application of novel, more efficacious anti-cancer vaccine therapies that inhibit tumor progression and prevent acquisition of tumor resistance. We have created and established a portfolio of validated peptide epitopes against multiple receptor tyrosine kinases and we have identified the most biologically effective combinations of EGFR (HER-1), HER-2, HER-3, VEGF and IGF-1R peptide vaccines/mimics to selectively inhibit multiple receptors and signaling pathways. The strategy is based on the use of chimeric conformational B-cell epitope peptides incorporating "promiscuous" T-cell epitopes that afford the possibility of generating an enduring immune response, eliciting protein-reactive high-affinity anti-peptide antibodies as potential vaccines and peptide mimics that act as antagonists to receptor signaling that drive cancer metastasis. In this review we will summarize our ongoing studies based on the development of combinatorial immunotherapeutic strategies that act synergistically to enhance immune-mediated tumor killing aimed at addressing mechanisms of tumor resistance for several tumor types.

The evaluation of the association between the metabolic syndrome and tumor grade and stage of bladder cancer in a Chinese population

Objective

The objective of this article was to summarize the relationship between some components of metabolic syndrome (MetS) and the histopathologic findings in bladder cancer in a Chinese population.

Methods

We retrospectively analyzed data of 323 patients from the Department of Urology, Second Hospital of Tianjin Medical University between January 2012 and January 2014. All the patients were diagnosed with bladder cancer for the first time. Age, height, weight, histologic stage, grade, the presence of hypertension, diabetes mellitus, and body mass index were evaluated. The 2009 American Joint Committee on Cancer TNM staging system was used, with Ta and T1 tumors accepted as lower stage and T2, T3, and T4 tumors as higher stage bladder cancers. Also, pathologists assigned tumor grade according to the 1973 World Health Organization grading system. Noninvasive papillary urothelial neoplasms of low malignant potential were regarded as low grade. Analyses were completed using chi-square tests and logistic regression analysis.

Results

Of the 323 patients, 164 had hypertension, 151 had diabetes mellitus, and 213 had a body mass index ≥25 kg/m². MetS was significantly associated with histologic grade (P<0.001) and stage (P=0.006) of bladder cancer. Adjusted for age in binary logistic regression analysis, the presence of MetS predicts the risk of higher T stage (odds ratio =4.029, P<0.001) and grade (odds ratio =3.870, P<0.001) of bladder cancer.

Conclusion

The patients with MetS in the People’s Republic of China were found to have statistically significant higher T stage and grade of bladder cancer.

Diabetes Type 2 and Pancreatic Cancer: A History Unfolding

Pancreatic Cancer is the fourth cause of cancer-related deaths in the United States. Up to 80% of pancreatic cancer patients present with either new-onset type 2 diabetes or impaired glucose tolerance at the time of diagnosis. Recent literature suggests that diabetes mellitus type 2 is a risk factor, a manifestation and a prognostic factor for pancreatic cancer. This article is intended to clarify the evidence about diabetes as a risk factor for pancreatic cancer.

Does diabetes mellitus affect presentation, stage and survival in operable pancreatic cancer?

BACKGROUND

The aim of the study is to investigate differences in clinical presentation, disease stage and survival of operable pancreatic cancer patients with new onset DM compared to long standing diabetes mellitus (DM) and non diabetics.

METHODS

A prospectively maintained pancreatic cancer surgery database of a tertiary care teaching hospital from January 2006 to August 2012 was reviewed. Only patients with a histological diagnosis of pancreatic carcinoma (PC) were included in final analysis. DM was defined as HbA1c >6.5% or any patient on anti-diabetic treatment regardless of HbA1c value. New onset DM was defined when diagnosed within two preceding years of surgery. Patients were stratified into two groups: DM and non DM. Among the DM patients, patients with new onset DM were further stratified and studied separately. Staging of PC was performed according to the 6(th) edition of AJCC. Survival of patients with PC was determined by reviewing medical records. Patients and their families were contacted if there was no existing follow-up.

RESULTS

Eighty-six patients (n=55, 63.9% male) with a mean age of 62 years (range, 29-85 years) underwent pancreatic cancer surgery during the study period. Of the 86 patients, 30 (34%) had DM of which eight patients (9% overall) had new onset DM. DM patients tended to be older compared to non DM patients (67.8 vs. 58.5 years, P=0.0005). The majority of non DM patients were symptomatic (98.2%), and there was a tendency for DM group patients to be asymptomatic at presentation (13.3% vs. 1.8%, P=0.05). Abdominal pain was less common in DM patients compared to non DM patients (30% vs. 53.6%, P=0.04). The median duration of new onset DM prior to diagnosis of PC was 2 months (range, 1-23 months). There was a tendency for DM patients to present at an early stage (stage I and stage II) (P=0.08). There was no difference in survival (P=0.17) for new onset DM compared to long standing DM and non DM patients.

CONCLUSIONS

DM patients tend to be older and are less likely to present with abdominal pain. Asymptomatic presentation and early stage disease tends to occur in DM patients. A larger sample size is required to determine if survival of new onset DM patients differs from long standing and non DM patients.

New therapeutic targets for cancer bone metastasis

Bone metastases are dejected consequences of many types of tumors including breast, prostate, lung, kidney, and thyroid cancers. This complicated process begins with the successful tumor cell epithelial-mesenchymal transition, escape from the original site, and penetration into the circulation. The homing of tumor cells to the bone depends on both tumor-intrinsic traits and various molecules supplied by the bone metastatic niche. The colonization and growth of cancer cells in the osseous environment, which awaken their dormancy to form micro- and macro-metastasis, involve an intricate interaction between the circulating tumor cells and local bone cells including osteoclasts, osteoblasts, adipocytes, and macrophages. We discuss the most recent advances in the identification of new molecules and novel mechanisms during each step of bone metastasis that may serve as promising therapeutic targets.

Insulin-like growth factor-1 receptor is associated with better prognosis in classical Hodgkin's lymphoma: Correlation with MET expression

The purpose of this study was to examine the prognostic significance of insulin-like growth factor-1 receptor (IGF-1R) expression alone and in relation to the expression of the MET- receptor and the MET-homologous receptor RON, in classical Hodgkin's lymphoma (cHL). Tumour samples from patients with cHL (n = 202; median age 37.5 years) were analysed retrospectively for IGF-R1, MET or RON expression by immunohistochemistry using tissue microarrays. The median follow-up time was 3.7 years (range, 0.1-20 years). Twenty-nine patients (14.3%) expressed IGF-1R protein in Hodgkin/Reed-Sternberg (HRS) cells, which was associated with a better overall survival (OS) (P = 0.036). IGF-1R expression was closely associated with MET receptor expression and low level of lactate dehydrogenase. In patients with cHL receiving doxorubicin, bleomycin, vinblastine and dacarbazine, those expressing IGF-1R showed a trend towards better OS and event-free survival than IGF-1R-negative patients (P = 0.129 and P = 0.115 respectively), but statistical significance was not reached. This study suggests that IGF-1R expression could be associated with better clinical outcome in cHL but is significantly associated with the expression of MET receptor.

Oxygen in human health from life to death--An approach to teaching redox biology and signaling to graduate and medical students

In the absence of oxygen human life is measured in minutes. In the presence of oxygen, normal metabolism generates reactive species (ROS) that have the potential to cause cell injury contributing to human aging and disease. Between these extremes, organisms have developed means for sensing oxygen and ROS and regulating their cellular processes in response. Redox signaling contributes to the control of cell proliferation and death. Aberrant redox signaling underlies many human diseases. The attributes acquired by altered redox homeostasis in cancer cells illustrate this particularly well. This teaching review and the accompanying illustrations provide an introduction to redox biology and signaling aimed at instructors of graduate and medical students.

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The ability to sense oxygen and respond to oxidative stress is ancient.

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Chemical and kinetic properties of ROS are key to understanding redox signaling.

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Redox signaling participates in normal control of cell proliferation and death.

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Aberrant redox signaling contributes to the hallmarks of cancer.

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Novel redox-based chemotherapeutics are being developed.

Evasion of anti-growth signaling: A key step in tumorigenesis and potential target for treatment and prophylaxis by natural compounds

The evasion of anti-growth signaling is an important characteristic of cancer cells. In order to continue to proliferate, cancer cells must somehow uncouple themselves from the many signals that exist to slow down cell growth. Here, we define the anti-growth signaling process, and review several important pathways involved in growth signaling: p53, phosphatase and tensin homolog (PTEN), retinoblastoma protein (Rb), Hippo, growth differentiation factor 15 (GDF15), AT-rich interactive domain 1A (ARID1A), Notch, insulin-like growth factor (IGF), and Krüppel-like factor 5 (KLF5) pathways. Aberrations in these processes in cancer cells involve mutations and thus the suppression of genes that prevent growth, as well as mutation and activation of genes involved in driving cell growth. Using these pathways as examples, we prioritize molecular targets that might be leveraged to promote anti-growth signaling in cancer cells. Interestingly, naturally occurring phytochemicals found in human diets (either singly or as mixtures) may promote anti-growth signaling, and do so without the potentially adverse effects associated with synthetic chemicals. We review examples of naturally occurring phytochemicals that may be applied to prevent cancer by antagonizing growth signaling, and propose one phytochemical for each pathway. These are: epigallocatechin-3-gallate (EGCG) for the Rb pathway, luteolin for p53, curcumin for PTEN, porphyrins for Hippo, genistein for GDF15, resveratrol for ARID1A, withaferin A for Notch and diguelin for the IGF1-receptor pathway. The coordination of anti-growth signaling and natural compound studies will provide insight into the future application of these compounds in the clinical setting.

Dual PI3K/mTOR Inhibitors Induce Rapid Overactivation of the MEK/ERK Pathway in Human Pancreatic Cancer Cells through Suppression of mTORC2

The PI3K/AKT/mTOR pathway, which is aberrantly stimulated in many cancer cells, has emerged as a target for therapy. However, mTORC1/S6K also mediates negative feedback loops that attenuate upstream signaling. Suppression of these feedback loops opposes the growth-suppressive effects of mTOR inhibitors and leads to drug resistance. Here, we demonstrate that treatment of PANC-1 or MiaPaCa-2 pancreatic ductal adenocarcinoma (PDAC) cells with the dual PI3K/mTOR kinase inhibitor (PI3K/TOR-KI) BEZ235 blocked mTORC1/S6K activation (scored by S6 phosphorylation at Ser(240/244)), mTORC1/4E-BP1 (assayed by 4E-BP1 phosphorylation at Thr(37/46)), and mTORC2-mediated AKT phosphorylation at Ser(473), in a concentration-dependent manner. Strikingly, BEZ235 markedly enhanced the MEK/ERK pathway in a dose-dependent manner. Maximal ERK overactivation coincided with complete inhibition of phosphorylation of AKT and 4E-BP1. ERK overactivation was induced by other PI3K/TOR-KIs, including PKI-587 and GDC-0980. The MEK inhibitors U126 or PD0325901 prevented ERK overactivation induced by PI3K/TOR-KIs. The combination of BEZ235 and PD0325901 caused a more pronounced inhibition of cell growth than that produced by each inhibitor individually. Mechanistic studies assessing PI3K activity in single PDAC cells indicate that PI3K/TOR-KIs act through a PI3K-independent pathway. Doses of PI3K/TOR-KIs that enhanced MEK/ERK activation coincided with those that inhibited mTORC2-mediated AKT phosphorylation on Ser(473), suggesting a role of mTORC2. Knockdown of RICTOR via transfection of siRNA markedly attenuated the enhancing effect of BEZ235 on ERK phosphorylation. We propose that dual PI3K/mTOR inhibitors suppress a novel negative feedback loop mediated by mTORC2, thereby leading to enhanced MEK/ERK pathway activity in pancreatic cancer cells.

IGF-1R peptide vaccines/mimics inhibit the growth of BxPC3 and JIMT-1 cancer cells and exhibit synergistic antitumor effects with HER-1 and HER-2 peptides

The insulin-like growth factor-1 receptor (IGF-1R) plays a crucial role in cellular growth, proliferation, transformation, and inhibition of apoptosis. A myriad of human cancer types have been shown to overexpress IGF-1R, including breast and pancreatic adenocarcinoma. IGF-1R signaling interferes with numerous receptor pathways, rendering tumor cells resistant to chemotherapy, anti-hormonal therapy, and epidermal growth factor receptor (EGFR, also known as HER-1) and v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2, (ERBB2, best known as HER-2) -targeted therapies. Targeting the IGF:IGF-1R axis with innovative peptide inhibitors and vaccine antibodies thus represents a promising therapeutic strategy to overcome drug resistance and to provide new avenues for individualized and combinatorial treatment strategies. In this study, we designed, synthesized, and characterized several B-cell epitopes from the IGF-1:IGF-1R axis. The chimeric peptide epitopes were highly immunogenic in outbred rabbits, eliciting high levels of peptide vaccine antibodies. The IGF-1R peptide antibodies and peptide mimics inhibited cell proliferation and receptor phosphorylation, induced apoptosis and antibody-dependent cellular cytotoxicity (ADCC), and significantly inhibited tumor growth in the transplantable BxPC-3 pancreatic and JIMT-1 breast cancer models. Our results showed that the peptides and antibodies targeting residues 56-81 and 233-251 are potential therapeutic and vaccine candidates for the treatment of IGF-1R-expressing cancers, including those that are resistant to the HER-2-targeted antibody, trastuzumab. Additionally, we found additive antitumor effects for the combination treatment of the IGF-1R 56-81 epitope with HER-1-418 and HER-2-597 epitopes. Treatment with the IGF-1R/HER-1 or IGF-1R/HER-2 combination inhibited proliferation, invasion, and receptor phosphorylation, and induced apoptosis and ADCC, to a greater degree than single agents.

Mirk/dyrk1B kinase is upregulated following inhibition of mTOR

The PI3K/PTEN/Akt/mTOR/p70S6K pathway is one of the most frequently deregulated signaling pathways in solid tumors and has a functional role in drug resistance. However, targeting this pathway leads to compensatory activation of several mediators of cell survival. Expression of the reactive oxygen species-controlling kinase Mirk/dyrk1B was increased severalfold by the mammalian target of rapamycin (mTOR) inhibitors RAD001, WYE354 and rapamycin, with less effect by the Akt inhibitors AZD5363 and MK-2206. Upregulation of Mirk messenger RNA (mRNA) expression was mediated by cyclic AMP response element binding protein (CREB) binding to two sites in the Mirk promoter upstream of the transcription start site and one site within exon 4. Depletion of CREB reduced Mirk expression, whereas depletion of mTOR increased it. Moreover, hydroxytamoxifen activation of an Akt-estrogen receptor construct blocked an increase in Mirk mRNA and protein. Addition of a Mirk/dyrk1B kinase inhibitor increased the sensitivity of Panc1 pancreatic cancer cells and three different ovarian cancer cell lines to the mTOR inhibitor RAD001. Targeting Mirk kinase could improve the utility of mTOR inhibitors and so presents an attractive drug target.

Co-targeting the IGF system and HIF-1 inhibits migration and invasion by (triple-negative) breast cancer cells

Background:

Metastatic triple-negative breast cancer is mostly incurable, due to lack of suitable drug targets. The insulin-like growth factor (IGF) system could provide such a target, and IGF-1 receptor (IGF-1R)-directed agents are already available, but seem unable to control all the complexities of the system, including crosstalk with hypoxia-inducible pathways.

Methods:

Migration of triple-negative MDA-231 breast cancer cells and its modulation by IGFs, the IGF-1R inhibitor NVP-AEW541 and the IGF-2-sequestering monoclonal antibody MAB292 were assessed by the scratch wound healing and Boyden chamber assays; the effect of topotecan (inhibiting hypoxia-inducible factor-1 (HIF-1)) under hypoxia was also evaluated. Constitutive as well as drug-modulated levels of components of the IGF and HIF-1 pathways were evaluated by western blotting and qPCR.

Results:

IGF-induced migration of MDA-231 cells was not abrogated by the IGF-1R inhibitor NVP-AEW541, whereas IGF-2 sequestration by MAB292 significantly reduced cell migration. Under hypoxia, topotecan was also effective, likely by reducing HIF-1-induced IGF-2 release. Simultaneous targeting of IGF-1R and IGF-2 or HIF-1 completely abolished cell migration.

Conclusions:

IR activation may account for the failure of NVP-AEW541 to suppress MDA-231 cell migration. Ligand-targeting compounds, or co-inhibition of the IGF and HIF-1 systems, may prevent activation of compensatory signalling, thereby providing a valuable addition to IGF-1R inhibitor-based therapies.

Genetic determinants and potential therapeutic targets for pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer deaths in both men and women in the United States, carrying a 5-year survival rate of approximately 5%, which is the poorest prognosis of any solid tumor type. Given the dismal prognosis associated with PDAC, a more thorough understanding of risk factors and genetic predisposition has important implications not only for cancer prevention, but also for screening techniques and the development of personalized therapies. While screening of the general population is not recommended or practicable with current diagnostic methods, studies are ongoing to evaluate its usefulness in people with at least 5- to 10-fold increased risk of PDAC. In order to help identify high-risk populations who would be most likely to benefit from early detection screening tests for pancreatic cancer, discovery of additional pancreatic cancer susceptibility genes is crucial. Thus, specific gene-based, gene-product, and marker-based testing for the early detection of pancreatic cancer are currently being developed, with the potential for these to be useful as potential therapeutic targets as well. The goal of this review is to provide an overview of the genetic basis for PDAC with a focus on germline and familial determinants. A discussion of potential therapeutic targets and future directions in screening and treatment is also provided.

Mechanisms of obesity-induced gastrointestinal neoplasia

Obesity is among the fastest growing diseases worldwide; treatment is inadequate, and associated disorders, including gastrointestinal cancers, have high morbidity and mortality. An increased understanding of the mechanisms of obesity-induced carcinogenesis is required to develop methods to prevent or treat these cancers. In this report, we review the mechanisms of obesity-associated colorectal, esophageal, gastric, and pancreatic cancers and potential treatment strategies.

RAF kinase inhibitor-independent constitutive activation of Yes-associated protein 1 promotes tumor progression in thyroid cancer

The transcription coactivator Yes-associated protein 1 (YAP1) is regulated by the Hippo tumor suppressor pathway. However, the role of YAP1 in thyroid cancer, which is frequently associated with the BRAF^V600E mutation, remains unknown. This study aimed to investigate the role of YAP1 in thyroid cancer. YAP1 was overexpressed in papillary (PTC) and anaplastic thyroid cancer, and nuclear YAP1 was more frequently detected in BRAF^V600E (+) PTC. In the thyroid cancer cell lines TPC-1 and HTH7, which do not have the BRAF^V600E mutation, YAP1 was cytosolic and inactive at high cell densities. In contrast, YAP1 was retained in the nucleus and its target genes were expressed in the thyroid cancer cells 8505C and K1, which harbor the BRAF^V600E mutation, regardless of cell density. Furthermore, the nuclear activation of YAP1 in 8505C was not inhibited by RAF or MEK inhibitor. In vitro experiments, YAP1 silencing or overexpression affected migratory capacities of 8505C and TPC-1 cells. YAP1 knockdown resulted in marked decrease of tumor volume, invasion and distant metastasis in orthotopic tumor xenograft mouse models using the 8505C thyroid cancer cell line. Taken together, YAP1 is involved in the tumor progression of thyroid cancer and YAP1-mediated effects might not be affected by the currently used RAF kinase inhibitors.

Treatment options for advanced pancreatic cancer: a review

Advanced pancreatic adenocarcinoma historically has a poor prognosis and the mortality rate has remained unchanged for over a decade. Common treatment options for patients with advanced pancreatic cancer include chemoradiation and/or chemotherapy. Single-agent gemcitabine has been considered the standard of care since 1997. Recently published findings indicate that the oxaliplatin, irinotecan, fluorouracil and leucovorin (FOLFIRINOX) treatment regimen significantly improves overall survival compared with gemcitabine. Research has shifted to focus on understanding the causes the resistance of pancreatic cancer to chemotherapy and potential methods to overcome it. This review will focus on the current treatment options, the evolution of targeted therapy, novel agents on the horizon and potential options to ameliorate chemoresistance.

Type 2 diabetes mellitus and pancreatic cancer

Tumorigenesis of pancreatic cancer (PC) and the pathophysiology of type 2 diabetes mellitus (DM2) are emerging as intertwined pathways. As the operative morbidity and mortality of pancreatectomy has improved, incidence has increased and survival has remained mostly unchanged. The diagnosis of DM2 suggests pancreatic dysfunction and possible early carcinogenesis. DM2 is a significant comorbidity predicting worse outcomes in patients undergoing pancreatic resection as part of the treatment of PC. This article examines this phenomena and suggests possible approaches to screening and diagnosis.

Different patterns of Akt and ERK feedback activation in response to rapamycin, active-site mTOR inhibitors and metformin in pancreatic cancer cells

The mTOR pathway is aberrantly stimulated in many cancer cells, including pancreatic ductal adenocarcinoma (PDAC), and thus it is a potential target for therapy. However, the mTORC1/S6K axis also mediates negative feedback loops that attenuate signaling via insulin/IGF receptor and other tyrosine kinase receptors. Suppression of these feed-back loops unleashes over-activation of upstream pathways that potentially counterbalance the antiproliferative effects of mTOR inhibitors. Here, we demonstrate that treatment of PANC-1 or MiaPaCa-2 pancreatic cancer cells with either rapamycin or active-site mTOR inhibitors suppressed S6K and S6 phosphorylation induced by insulin and the GPCR agonist neurotensin. Rapamycin caused a striking increase in Akt phosphorylation at Ser(473) while the active-site inhibitors of mTOR (KU63794 and PP242) completely abrogated Akt phosphorylation at this site. Conversely, active-site inhibitors of mTOR cause a marked increase in ERK activation whereas rapamycin did not have any stimulatory effect on ERK activation. The results imply that first and second generation of mTOR inhibitors promote over-activation of different pro-oncogenic pathways in PDAC cells, suggesting that suppression of feed-back loops should be a major consideration in the use of these inhibitors for PDAC therapy. In contrast, metformin abolished mTORC1 activation without over-stimulating Akt phosphorylation on Ser(473) and prevented mitogen-stimulated ERK activation in PDAC cells. Metformin induced a more pronounced inhibition of proliferation than either KU63794 or rapamycin while, the active-site mTOR inhibitor was more effective than rapamycin. Thus, the effects of metformin on Akt and ERK activation are strikingly different from allosteric or active-site mTOR inhibitors in PDAC cells, though all these agents potently inhibited the mTORC1/S6K axis.

Hypoxia-inducing factors as master regulators of stemness properties and altered metabolism of cancer- and metastasis-initiating cells

Accumulating lines of experimental evidence have revealed that hypoxia-inducible factors, HIF-1α and HIF-2α, are key regulators of the adaptation of cancer- and metastasis-initiating cells and their differentiated progenies to oxygen and nutrient deprivation during cancer progression under normoxic and hypoxic conditions. Particularly, the sustained stimulation of epidermal growth factor receptor (EGFR), insulin-like growth factor-1 receptor (IGF-1R), stem cell factor (SCF) receptor KIT, transforming growth factor-β receptors (TGF-βRs) and Notch and their downstream signalling elements such as phosphatidylinositol 3′-kinase (PI3K)/Akt/molecular target of rapamycin (mTOR) may lead to an enhanced activity of HIFs. Moreover, the up-regulation of HIFs in cancer cells may also occur in the hypoxic intratumoral regions formed within primary and secondary neoplasms as well as in leukaemic cells and metastatic prostate and breast cancer cells homing in the hypoxic endosteal niche of bone marrow. The activated HIFs may induce the expression of numerous gene products such as induced pluripotency-associated transcription factors (Oct-3/4, Nanog and Sox-2), glycolysis- and epithelial-mesenchymal transition (EMT) programme-associated molecules, including CXC chemokine receptor 4 (CXCR4), snail and twist, microRNAs and angiogenic factors such as vascular endothelial growth factor (VEGF). These gene products in turn can play critical roles for high self-renewal ability, survival, altered energy metabolism, invasion and metastases of cancer cells, angiogenic switch and treatment resistance. Consequently, the targeting of HIF signalling network and altered metabolic pathways represents new promising strategies to eradicate the total mass of cancer cells and improve the efficacy of current therapies against aggressive and metastatic cancers and prevent disease relapse.

Prognostic significance of serum levels of vascular endothelial growth factor and insulin-like growth factor-1 in advanced gastric cancer patients treated with FOLFOX chemotherapy

BACKGROUND

Tumor vascular endothelial growth factor (VEGF) is a key angiogenic factor and may have an impact on tumor progression and response to chemotherapy. The insulin-like growth factor (IGF) system is related to cell proliferation and tumor growth. However, there is limited available data regarding the clinical and prognostic significance of VEGF or IGF-1 in advanced gastric cancer. The aim of this study was to evaluate the prognostic significance of serum VEGF and IGF-1 levels in advanced gastric cancer patients who were treated with oxaliplatin/5-fluorouracil (FOLFOX).

METHODS

The study population consisted of 100 advanced gastric cancer patients (median age 56 years). Patients were treated with oxaliplatin 85 mg/m(2) as a 2-hour infusion on day 1 plus leucovorin 20 mg/m(2) over 10 min, followed by a 5-fluorouracil (5-FU) bolus 400 mg/m(2) and 22 h of continuous infusion of 600 mg/m(2) on days 1-2. Treatment was repeated in 2-week intervals. The levels of serum VEGF and IGF-1 were measured using enzyme-linked immunoassays.

RESULTS

There was a significant correlation between the serum level of VEGF and Lauren's classification (p = 0.030) and previous operations (p = 0.010). IGF-1 was associated with the number of metastases (p = 0.012). The median level of serum VEGF was decreased after FOLFOX chemotherapy (p = 0.034). However, none of the measured serum markers were significantly correlated with response. In univariate analysis, overall survival (p < 0.001) was significantly shorter in patients with high serum levels of VEGF. Multivariate analysis revealed that VEGF was an independent factor for overall survival (HR 2.221; 95% CI 1.377-3.583, p = 0.001). Furthermore, IGF-1 had no significant influence on the clinical outcome.

CONCLUSION

A high level of serum VEGF is an independent prognostic factor in patients with advanced gastric cancer treated with chemotherapy. This may help to identify the patients who are more sensitive to the FOLFOX regimen.

The role of the insulin-like growth factor-I receptor in malignancy: an update

In the past three decades, evidence has been accumulating that the IGF-I receptor/ligand system plays an important role in malignant disease. This has led to a search for specific inhibitors of the IGF receptor for cancer therapy, revealing some predictable, but also unexpected challenges. Here we review recent data that highlight the essential role of the IGF axis in several important steps in cancer cell progression and metastasis and highlight cellular processes that have been the focus of much interest and new insight in recent years. Strategies used to target the IGF axis clinically are summarized and the obstacles encountered are discussed.

Adaptive and maladaptive cardiorespiratory responses to continuous and intermittent hypoxia mediated by hypoxia-inducible factors 1 and 2

Hypoxia is a fundamental stimulus that impacts cells, tissues, organs, and physiological systems. The discovery of hypoxia-inducible factor-1 (HIF-1) and subsequent identification of other members of the HIF family of transcriptional activators has provided insight into the molecular underpinnings of oxygen homeostasis. This review focuses on the mechanisms of HIF activation and their roles in physiological and pathophysiological responses to hypoxia, with an emphasis on the cardiorespiratory systems. HIFs are heterodimers comprised of an O(2)-regulated HIF-1α or HIF-2α subunit and a constitutively expressed HIF-1β subunit. Induction of HIF activity under conditions of reduced O(2) availability requires stabilization of HIF-1α and HIF-2α due to reduced prolyl hydroxylation, dimerization with HIF-1β, and interaction with coactivators due to decreased asparaginyl hydroxylation. Stimuli other than hypoxia, such as nitric oxide and reactive oxygen species, can also activate HIFs. HIF-1 and HIF-2 are essential for acute O(2) sensing by the carotid body, and their coordinated transcriptional activation is critical for physiological adaptations to chronic hypoxia including erythropoiesis, vascularization, metabolic reprogramming, and ventilatory acclimatization. In contrast, intermittent hypoxia, which occurs in association with sleep-disordered breathing, results in an imbalance between HIF-1α and HIF-2α that causes oxidative stress, leading to cardiorespiratory pathology.

Adamantyl Retinoid-Related Molecules Induce Apoptosis in Pancreatic Cancer Cells by Inhibiting IGF-1R and Wnt/β-Catenin Pathways

Pancreatic carcinoma has a dismal prognosis as it often presents as locally advanced or metastatic. We have found that exposure to adamantyl-substituted retinoid-related (ARR) compounds 3-Cl-AHPC and AHP3 resulted in growth inhibition and apoptosis induction in PANC-1, Capan-2, and MiaPaCa-2 pancreatic cancer cell lines. In addition, AHP3 and 3-Cl-AHPC inhibited growth and induced apoptosis in spheres derived from the CD44⁺/CD24⁺ (CD133⁺/EpCAM⁺) stem-like cell population isolated from the pancreatic cancer cell lines. 3-Cl-AHPC-induced apoptosis was preceded by decreasing expression of IGF-1R, cyclin D1, β-catenin, and activated Notch-1 in the pancreatic cancer cell lines. Decreased IGF-1R expression inhibited PANC-1 proliferation, enhanced 3-Cl-AHPC-mediated apoptosis, and significantly decreased sphere formation. 3-Cl-AHPC inhibited the Wnt/β-catenin pathway as indicated by decreased β-catenin nuclear localization and inhibited Wnt/β-catenin activation of transcription factor TCF/LEF. Knockdown of β-catenin using sh-RNA also induced apoptosis and inhibited growth in pancreatic cancer cells. Thus, 3-Cl-AHPC and AHP3 induce apoptosis in pancreatic cancer cells and cancer stem-like cells and may serve as an important potential therapeutic agent in the treatment of pancreatic cancer.

Diabetes and pancreatic cancer

Type 2 diabetes mellitus is likely the third modifiable risk factor for pancreatic cancer after cigarette smoking and obesity. Epidemiological investigations have found that long-term type 2 diabetes mellitus is associated with a 1.5-fold to 2.0-fold increase in the risk of pancreatic cancer. A causal relationship between diabetes and pancreatic cancer is also supported by findings from prediagnostic evaluations of glucose and insulin levels in prospective studies. Insulin resistance and associated hyperglycemia, hyperinsulinemia, and inflammation have been suggested to be the underlying mechanisms contributing to development of diabetes-associated pancreatic cancer. Signaling pathways that regulate the metabolic process also play important roles in cell proliferation and tumor growth. Use of the antidiabetic drug metformin has been associated with reduced risk of pancreatic cancer in diabetics and recognized as an antitumor agent with the potential to prevent and treat this cancer. On the other hand, new-onset diabetes may indicate subclinical pancreatic cancer, and patients with new-onset diabetes may constitute a population in whom pancreatic cancer can be detected early. Biomarkers that help define high-risk individuals for clinical screening for pancreatic cancer are urgently needed. Why pancreatic cancer causes diabetes and how diabetes affects the clinical outcome of pancreatic cancer have yet to be fully determined. Improved understanding of the pathological mechanisms shared by diabetes and pancreatic cancer would be the key to the development of novel preventive and therapeutic strategies for this cancer.

Interaction between IGF-1 polymorphisms and overweight for the risk of pancreatic cancer in Japanese

Although several reports have described a possible association between insulin-like growth factors-1 (IGF-1) and pancreatic cancer (PC) risk, this association has not been evaluated in the non-Caucasian population. To assess the impact of IGF-1 polymorphisms on PC risk in Japanese, we conducted a case-control study which compared the frequency of ten single nucleotide polymorphisms (SNPs) and haplotypes of IGF-1. SNPs were investigated using the TaqMan method in 176 patients with PC and 1402 control subjects. Exposure to risk factors was assessed from the results of a self-administered questionnaire. Associations and gene-environment interactions were examined using an unconditional logistic regression model. We did not observe any significant main effect of IGF-1 loci, but did find interactions between rs5742714 and past and/or current body-mass index (BMI) status. Among patients with BMI > 25 at age 20, an increased PC risk was observed with the addition of the minor allele for rs5742714 (trend P = 0.048) and rs6214 (P = 0.043). Among patients with current BMI > 25, an increased or decreased PC risk was observed with the addition of the minor allele for rs5742714 (trend P = 0.046), rs4764887 (P = 0.031) and rs5742612 (P = 0.038). Haplotype analysis of IGF-1 showed a significant association among patients who were either or both previously or currently overweight. These findings suggest that IGF-1 polymorphisms may affect the development of PC in the Japanese population in combination with obesity. Further studies to confirm these findings are warranted.