Inhibiting PI3K reduces mammary tumor growth and induces hyperglycemia in a mouse model of insulin resistance and hyperinsulinemia

Role of epigenetic in cancer biology, in hematologic malignancies and in anticancer therapy

Major epigenetic changes are associated with carcinogenesis, including aberrant DNA methylations and post-translational modifications of histone. Indeed evidence accumulated in recent years indicates that inactivating DNA hypermethylation preferentially targets the subset of polycomb group (PcG) genes that are regulators of developmental processes. Conversely, activating DNA hypomethylation targets oncogenic signaling pathway genes, but outcomes of both events lead in the overexpression of oncogenic signaling pathways that contribute to the stem-like state of cancer cells. On the basis of recent evidence from population-basedclinical and experimental studies, we hypothesize that factors associated with risk for developing a hematologic malignancy (HM), such as metabolic syndrome and chronic inflammation, may trigger epigenetic mechanisms to increase the transcriptional expression of oncogenes and activate oncogenic signaling pathways. Signaling pathways associated with such risk factors include but are not limited to pro-inflammatory nuclear factor κB (NF-κB) and mitogenic, growth, and survival Janus kinase (JAK) intracellular non-receptor tyrosine kinase-triggered pathways. The latter includes signaling pathways such as transducer and activator of transcription (STAT), Ras GTPases/mitogen-activated protein kinases (MAPKs)/extracellular signal-related kinases (ERKs), phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR), and β-catenin pathways. Recent findings on epigenetic mechanisms at work in the biology of cancer and in HMs and their importance in the etiology and pathogenesis of these diseases are herein summarized and discussed. Furthermore, the role of epigenetic processes in the determination of biological identity, the consequences for interindividual variability in disease clinical profile, and the potential of epigenetic drugs in HMs are also considered.

Repurposing of atorvastatin and metformin denotes their individual and combined antiproliferative effects in non-small cell lung cancer

BACKGROUND

Due to the limited success in the treatment of lung adenocarcinomas, new treatment protocols are urgently needed to increase the curability rate and the survival of lung cancer patients.

OBJECTIVES

Although statins, like atorvastatin (Ator), and metformin (Met) are widely accepted as hypolipidemic and hypoglycemic drugs, respectively, there are many predictions about their enhancing antitumor effect when they are combined with traditional chemotherapeutics.

METHODS

The individual and combined antiproliferative potential of Ator and Met was tested by MTT-assay in non-small cell lung cancer (NSCLC) A549 cell line, compared to the corresponding effect of Gemcitabine (Gem) with implication on the mechanisms of action.

RESULTS

Initially, both drugs demonstrated concentration-dependent cytotoxicity in A549 cells. Also, their combination index (CI) indicated their synergistic effect at equi-IC50 concentration (CI = 0.00984). Moreover, Ator and/or Met-treated cells revealed disrupted patterns of SOD, CAT, GSH, MDA, and TAC, developed apoptosis, and larger fractions of the cell population were arrested in G0/G1 phase, particularly in cells dually-treated both Ator and Met. These observations were accompanied by downregulation in the expression of iNOS, HO-1, and the angiogenic marker VEGF, meanwhile, an altered expression of MAPK and AMPK was observed.

CONCLUSION

Conclusively, these data suggest that repurposing of Ator and Met demonstrates their individual and combined antiproliferative effect in non-small cell lung cancer and they may adopt a similar mechanism of action.

Predictive, preventive, and personalized medicine in breast cancer: targeting the PI3K pathway

Breast cancer (BC) is a multifaceted disease characterized by distinct molecular subtypes and varying responses to treatment. In BC, the phosphatidylinositol 3-kinase (PI3K) pathway has emerged as a crucial contributor to the development, advancement, and resistance to treatment. This review article explores the implications of the PI3K pathway in predictive, preventive, and personalized medicine for BC. It emphasizes the identification of predictive biomarkers, such as PIK3CA mutations, and the utility of molecular profiling in guiding treatment decisions. The review also discusses the potential of targeting the PI3K pathway for preventive strategies and the customization of therapy based on tumor stage, molecular subtypes, and genetic alterations. Overcoming resistance to PI3K inhibitors and exploring combination therapies are addressed as important considerations. While this field holds promise in improving patient outcomes, further research and clinical trials are needed to validate these approaches and translate them into clinical practice.

Alpha-Mangosteen lessens high-fat/high-glucose diet and low-dose streptozotocin induced-hepatic manifestations in the insulin resistance rat model

CONTEXT

α-Mangosteen (α-MG) attenuates insulin resistance (IR). However, it is still unknown whether α-MG could alleviate hepatic manifestations in IR rats.

OBJECTIVE

To investigate the effect of α-MG on alleviating hepatic manifestations in IR rats through AMP-activated protein kinase (AMPK) and sterol-regulatory element-binding protein-1 (SREBP-1) pathway.

MATERIALS AND METHODS

IR was induced by exposing male Sprague-Dawley rats (180-200 g) to high-fat/high-glucose diet and low-dose injection of streptozotocin (HF/HG/STZ), then treated with α-MG at a dose of 100 or 200 mg/kg/day for 8 weeks. At the end of the study (11 weeks), serum and liver were harvested for biochemical analysis, and the activity of AMPK, SREBP-1c, acetyl-CoA carboxylase (ACC), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, insulin receptor substrate (IRS)-1, Bax and liver histopathology were analyzed.

RESULTS

α-MG at both doses significantly lowered ALT, AST, triglyceride, and cholesterol total by 16.5, 15.7, 38, and 36%, respectively. These beneficial effects of α-MG are associated with the downregulation of the IR-induced inflammation in the liver. Furthermore, α-MG, at both doses, activated AMPK by 24-29 times and reduced SREBP-1c by 44-50% as well as ACC expression by 19-31% similar to metformin. All treatment groups showed liver histopathology improvement regarding fat deposition in the liver.

CONCLUSIONS

Based on the findings demonstrated, α-MG protected against HF/HG/STZ-induced hepatic manifestations of the IR rats, at least in part via the modulation of the AMPK/SREBP-1c/ACC pathway and it could be a potential drug candidate to prevent IR-induced hepatic manifestations.

Exploring and exploiting the host cell autophagy during Mycobacterium tuberculosis infection

Tuberculosis, caused by Mycobacterium tuberculosis, is a fatal infectious disease that prevails to be the second leading cause of death from a single infectious agent despite the availability of multiple drugs for treatment. The current treatment regimen involves the combination of several drugs for 6 months that remain ineffective in completely eradicating the infection because of several drawbacks, such as the long duration of treatment and the side effects of drugs causing non-adherence of patients to the treatment regimen. Autophagy is an intracellular degradative process that eliminates pathogens at the early stages of infection. Mycobacterium tuberculosis's unique autophagy-blocking capability makes it challenging to eliminate compared to usual pathogens. The present review discusses recent advances in autophagy-inhibiting factors and mechanisms that could be exploited to identify autophagy-inducing chemotherapeutics that could be used as adjunctive therapy with the existing first-line anti-TB agent to shorten the duration of therapy and enhance cure rates from multidrug-resistant tuberculosis (MDR-TB) and extreme drug-resistant tuberculosis (XDR-TB).

First-in-human phase Ia study of the PI3Kα inhibitor CYH33 in patients with solid tumors

PIK3CA mutations are highly prevalent in solid tumors. Targeting phosphatidylinositol 3-kinase α is therefore an attractive strategy for treating cancers harboring PIK3CA mutations. Here, we report the results from a phase Ia, open label, dose-escalation and -expansion study (NCT03544905) of CYH33, a highly selective PI3Kα inhibitor, in advanced solid tumors. The primary outcomes were the safety, tolerability, maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of CYH33. The secondary outcomes included evaluation of pharmacokinetics, preliminary efficacy and changes in pharmacodynamic biomarkers in response to CYH33 treatment. The exploratory outcome was the relationship between the efficacy of CYH33 treatment and tumor biomarker status, including PIK3CA mutations. A total of 51 patients (19 in the dose escalation stage and 32 in the dose expansion stage) including 36 (70.6%) patients (4 in the dose escalation stage and 32 in the dose expansion stage) with PIK3CA mutations received CYH33 1-60 mg. The MTD of CYH33 was 40 mg once daily, which was also selected as the RP2D. The most common grade 3/4 treatment-related adverse events were hyperglycemia, rash, platelet count decreased, peripheral edema, and fatigue. Forty-two out of 51 patients were evaluable for response, the confirmed objective response rate was 11.9% (5/42). Among 36 patients harboring PIK3CA mutations, 28 patients were evaluable for response, the confirmed objective response rate was 14.3% (4/28). In conclusion, CYH33 exhibits a manageable safety profile and preliminary anti-tumor efficacy in solid tumors harboring PIK3CA mutations.

Cardio-Onco-Metabolism - Metabolic vulnerabilities in cancer and the heart

Cancer and cardiovascular diseases (CVDs) are the leading cause of death worldwide. Metabolic remodeling is a hallmark of both cancer and the failing heart. Tumors reprogram metabolism to optimize nutrient utilization and meet increased demands for energy provision, biosynthetic pathways, and proliferation. Shared risk factors for cancer and CVDs suggest intersecting mechanisms for disease pathogenesis and progression. In this review, we aim to highlight the role of metabolic remodeling in cancer and its potential to impair cardiac function. Understanding these mechanisms will help us develop biomarkers, better therapies, and identify patients at risk of developing heart disease after surviving cancer.

Alpelisib monotherapy for PI3K-altered, pre-treated advanced breast cancer: a phase 2 study

There is limited knowledge on the benefit of the α-subunit specific PI3K inhibitor alpelisib in later lines of therapy for advanced ER+HER2- and triple negative breast cancer (TNBC). We conducted a phase 2 multi-cohort study of alpelisib monotherapy in patients with advanced PI3K pathway mutant ER+HER2- and TNBC. In the intention to treat ER+ cohort, the overall response rate was 30% and the clinical benefit rate was 36%. Decline in PI3K pathway mutant ctDNA levels from baseline to week 8 while on therapy was significantly associated with a partial response, clinical benefit and improved progression free-survival (HR 0.24 95% CI 0.083 - 0.67, P = 0.0065). Detection of ESR1 mutations at baseline in plasma was also associated with clinical benefit and improved progression free survival (HR 0.22 95% CI 0.078 - 0.60, P = 0.003).

S.U.G.A.R: A Case to Outline Tactics for the Prevention of Alpelisib-Induced Hyperglycemia

Postmenopausal patients with metastatic breast cancer (mBC) may live years with their disease on therapies with minimal toxicities but they will eventually progress on first-line therapy. For those eligible for second-line therapy, PIK3CA mutation testing is recommended in estrogen receptor–positive, her2-negative disease. If present, alpelisib, a PI3K inhibitor, has been shown to improve progression-free survival. Hyperglycemia is a common side effect of alpelisib. We describe a case of diabetic ketoacidosis (DKA) necessitating treatment in the intensive care unit (ICU) in a woman with type 2 diabetes mellitus (T2DM) started on alpelisib. A 76-year-old female with diet-controlled T2DM and mBC was placed on second-line treatment with alpelisib after progression on first-line therapy. After more than 2 weeks of treatment, the patient presented to the emergency department with nausea and vomiting. Lab results showed DKA and she was admitted to the ICU for further management. This case highlights the need for a multidisciplinary approach to caring for patients who are started on a PI3K inhibitor. We propose 5 guidelines to prevent hyperglycemia in those started on apelisib: (1) strict criteria for initiating alpelisib, (2) understand the steps needed to prevent hyperglycemia, (3) get help from a multidisciplinary team, (4) act immediately when hyperglycemia is noted, and (5) record blood glucose values. By implementing these steps, we hope to prevent critical hyperglycemic episodes in vulnerable patients on alpelisib.

Management of Phosphatidylinositol-3-Kinase Inhibitor-Associated Hyperglycemia

Phosphatidylinositol-3-kinase (PI3K) pathway hyperactivation has been associated with the development of cancer and treatment resistance. PI3K inhibitors are now used to treat hormone receptor-positive (HR+), human epidermal growth factor receptor-2-negative (HER2-), PIK3CA-mutated advanced breast cancer. Hyperglycemia, a frequently observed adverse event with PI3K inhibitors (PI3Ki), is regarded as an on-target effect because inhibition of the PI3K pathway has been shown to decrease glucose transport and increase glycogenolysis and gluconeogenesis. PI3Ki-induced hyperglycemia results in a compensatory increase in insulin release, which has been shown to reduce the efficacy of treatment by reactivating the PI3K pathway in preclinical models. Patients with an absolute or relative deficiency in insulin, and those with insulin resistance or pancreatic dysfunction, may experience exacerbated or prolonged hyperglycemia. Therefore, the effective management of PI3Ki-associated hyperglycemia depends on early identification of patients at risk, frequent monitoring to allow prompt recognition of hyperglycemia and its sequelae, and initiating appropriate management strategies. Risk factors for the development of hyperglycemia include older age (≥75 years), overweight/obese at baseline, and family history of diabetes. Consultation with an endocrinologist is recommended for patients considered high risk. The management of PI3Ki-induced hyperglycemia requires an integrative approach that combines diets low in carbohydrates and glucose-lowering medications. Medications that do not affect the PI3K pathway are preferred as the primary and secondary agents for the management of hyperglycemia. These include metformin, sodium-glucose co-transporter 2 inhibitors, thiazolidinediones, and α-glucosidase inhibitors. Insulin should only be considered as a last-line agent for PI3Ki-associated hyperglycemia due to its stimulatory effect of PI3K signaling. Clinical studies show that alpelisib-associated hyperglycemia is reversible and manageable, rarely leading to treatment discontinuation. Management of PI3Ki-associated hyperglycemia in patients with breast cancer should focus on the prevention of acute and subacute complications of hyperglycemia, allowing patients to remain on anticancer treatment longer.

Obesity, Diabetes, and Increased Cancer Progression

Rates of obesity and diabetes have increased significantly over the past decades and the prevalence is expected to continue to rise further in the coming years. Many observations suggest that obesity and diabetes are associated with an increased risk of developing several types of cancers, including liver, pancreatic, endometrial, colorectal, and post-menopausal breast cancer. The path towards developing obesity and diabetes is affected by multiple factors, including adipokines, inflammatory cytokines, growth hormones, insulin resistance, and hyperlipidemia. The metabolic abnormalities associated with changes in the levels of these factors in obesity and diabetes have the potential to significantly contribute to the development and progression of cancer through the regulation of distinct signaling pathways. Here, we highlight the cellular and molecular pathways that constitute the links between obesity, diabetes, cancer risk and mortality. This includes a description of the existing evidence supporting the obesity-driven morphological and functional alternations of cancer cells and adipocytes through complex interactions within the tumor microenvironment.

A molecular link between diabetes and breast cancer: Therapeutic potential of repurposing incretin-based therapies for breast cancer

Female breast cancer recently surpassed lung cancer and became the most commonly diagnosed cancer worldwide. As per the recent data from WHO, breast cancer accounts for one out of every 8 cancer cases diagnosed among an estimated 2.3 million new cancer cases. Breast cancer is the most prevailing cancer type among women causing the highest number of cancer-related mortality. It has been estimated that in 2020, 68,5000 women died due to this disease. Breast cancers have varying degrees of molecular heterogeneity; therefore, they are divided into various molecular clinical sub types. Recent reports suggest that type 2 diabetes (one of the common chronic diseases worldwide) is linked to the higher incidence, accelerated progression, and aggressiveness of different cancers; especially breast cancer. Breast cancer is hormone-dependent in nature and has a cross-talk with metabolism. A number of antidiabetic therapies are known to exert beneficial effects on various types of cancers, including breast cancer. However, only a few reports are available on the role of incretin-based antidiabetic therapies in cancer as a whole and in breast cancer in particular. The present review sheds light on the potential of incretin based therapies on breast cancer and explores the plausible underlying mechanisms. Additionally, we have also discussed the sub types of breast cancer as well as the intricate relationship between diabetes and breast cancer.

Alpelisib-Induced Diabetic Ketoacidosis: A Case Report and Review of Literature

Objective

To report the first case of diabetic ketoacidosis (DKA) and its management in a patient with diet-controlled prediabetes and metastatic breast cancer treated with alpelisib, a PI3K (phosphatidylinosiotol-3-kinase) inhibitor.

Methods

Literature on the topic is reviewed. The case is that of a 66-year-old female with diet-controlled prediabetes and metastatic breast carcinoma who had initiated alpelisib 2 weeks prior to being admitted for diabetic ketoacidosis.

Results

Admission laboratory examination revealed a blood sugar of 1137 mg/dL, an anion gap of 25, large ketones in urine, and positive acetone in serum. The HbA1c level was 9.4% (79 mmol/mol) on admission, which had been 6.3% (45 mmol/mol) seven months earlier. She was discharged on subcutaneous insulin and instructed to discontinue alpelisib. Alpelisib was restarted 2 days later, which exacerbated her hyperglycemia within 24 hours. In the following months, her hyperglycemia was successfully managed with insulin and a SGLT 2 inhibitor. Unfortunately, her breast cancer progressed, ultimately leading to discontinuation of alpelisib. Blood sugar levels returned to a nondiabetic range upon discontinuation of alpelisib, and she is currently off all antihyperglycemic agents.

Conclusion

Although PI3KCA inhibitors remain a promising drug in patients with metastatic breast cancer who have not responded to previous treatment, patients must be closely monitored for adverse effects such as hyperglycemia. Hyperglycemia could be a potentially limiting side effect of alpelisib. The optimal management of hyperglycemia induced by alpelisib warrants further research.

Changes in protein expression due to metformin treatment and hyperinsulinemia in a human endometrial cancer cell line

The incidence of endometrial cancer (EC) has increased over the past years and mainly affects women above the age of 45 years. Metabolic diseases such as obesity and type II diabetes mellitus as well as associated conditions like polycystic ovary syndrome (PCOS), insulin resistance and hyperinsulinemia lead to elevated levels of circulating estrogens. Increased estrogen concentrations, in turn, further trigger the proliferation of endometrial cells and thus promote EC development and progression, especially in the absence of progesterone as seen in postmenopausal women. Elevated blood glucose levels in diabetic patients further contribute to the risk of EC development. Metformin is an insulin-sensitizing biguanide drug, commonly used in the treatment of type II diabetes mellitus, especially in obese patients. Besides its effects on glucose metabolism, metformin displayed anti-cancer effects in various cancer types, including EC. Direct anti-cancer effects of metformin target signaling pathways that are involved in cellular growth and proliferation, e.g. the AKT/PKB/mTOR pathway. Further proteins and pathways have been suggested as potential targets, but the underlying mechanism of action of metformin's anti-cancer activity is still not completely understood. In the present study, the effects of metformin on protein expression were investigated in the human EC cell line HEC-1A using an affinity proteomic approach. Cells were treated with 0.5 mmol/L metformin over a period of 7 days and changes in the expression pattern of 1,300 different proteins were compared to the expression in untreated control cells as well as insulin-treated cells. Insulin treatment (100 ng/mL) was incorporated into the study in order to implement a model for insulin resistance and associated hyperinsulinemia, conditions that are often observed in obese and diabetic patients. Furthermore, the culture medium was supplemented with 10 nmol/L ß-estradiol (E2) during treatments to mimic increased estrogen levels, a common risk factor for EC development. Based on the most prominent and significant changes in expression, a set of 80 proteins was selected and subjected to a more detailed analysis. The data revealed that metformin and insulin targeted similar pathways in the present study and mostly acted on proteins related to proliferation, migration and tumor immune response. These pathways may be affected in a tumor-promoting as well as a tumor-suppressing way by either metformin treatment or insulin supplementation. The consequences for the cells resulting from the detected expression changes were discussed in detail for several proteins. The presented data helps identify potential targets affected by metformin treatment in EC and allows for a better understanding of the mechanism of action of the biguanide drug's anti-cancer activity. However, further investigations are necessary to confirm the observations and conclusions drawn from the presented data after metformin administration, especially for proteins that were regulated in a favorable way, i.e. AKT3, CCND2, CD63, CD81, GFAP, IL5, IL17A, IRF4, PI3, and VTCN1. Further proteins might be of interest, where metformin counteracted unfavorable effects that have been induced by hyperinsulinemia.

Obesity, Type 2 Diabetes, and Cancer Risk

Obesity and type 2 diabetes have both been associated with increased cancer risk and are becoming increasingly prevalent. Metabolic abnormalities such as insulin resistance and dyslipidemia are associated with both obesity and type 2 diabetes and have been implicated in the obesity-cancer relationship. Multiple mechanisms have been proposed to link obesity and diabetes with cancer progression, including an increase in insulin/IGF-1 signaling, lipid and glucose uptake and metabolism, alterations in the profile of cytokines, chemokines, and adipokines, as well as changes in the adipose tissue directly adjacent to the cancer sites. This review aims to summarize and provide an update on the epidemiological and mechanistic evidence linking obesity and type 2 diabetes with cancer, focusing on the roles of insulin, lipids, and adipose tissue.

Hyperinsulinaemia in cancer

Elevated circulating insulin levels are frequently observed in the setting of obesity and early type 2 diabetes, as a result of insensitivity of metabolic tissues to the effects of insulin. Higher levels of circulating insulin have been associated with increased cancer risk and progression in epidemiology studies. Elevated circulating insulin is believed to be a major factor linking obesity, diabetes and cancer. With the development of targeted cancer therapies, insulin signalling has emerged as a mechanism of therapeutic resistance. Although metabolic tissues become insensitive to insulin in the setting of obesity, a number of mechanisms allow cancer cells to maintain their ability to respond to insulin. Significant progress has been made in the past decade in understanding the insulin receptor and its signalling pathways in cancer, and a number of lessons have been learnt from therapeutic failures. These discoveries have led to numerous clinical trials that have aimed to reduce the levels of circulating insulin and to abrogate insulin signalling in cancer cells. With the rising prevalence of obesity and diabetes worldwide, and the realization that hyperinsulinaemia may contribute to therapeutic failures, it is essential to understand how insulin and insulin receptor signalling promote cancer progression.

Endometrial Cancer as a Metabolic Disease with Dysregulated PI3K Signaling: Shedding Light on Novel Therapeutic Strategies

Endometrial cancer (EC) is one of the most common malignancies of the female reproductive organs. The most characteristic feature of EC is the frequent association with metabolic disorders. However, the components of these disorders that are involved in carcinogenesis remain unclear. Accumulating epidemiological studies have clearly revealed that hyperinsulinemia, which accompanies these disorders, plays central roles in the development of EC via the insulin-phosphoinositide 3 kinase (PI3K) signaling pathway as a metabolic driver. Recent comprehensive genomic analyses showed that over 90% of ECs have genomic alterations in this pathway, resulting in enhanced insulin signaling and production of optimal tumor microenvironments (TMEs). Targeting PI3K signaling is therefore an attractive treatment strategy. Several clinical trials for recurrent or advanced ECs have been attempted using PI3K-serine/threonine kinase (AKT) inhibitors. However, these agents exhibited far lower efficacy than expected, possibly due to activation of alternative pathways that compensate for the PIK3-AKT pathway and allow tumor growth, or due to adaptive mechanisms including the insulin feedback pathway that limits the efficacy of agents. Overcoming these responses with careful management of insulin levels is key to successful treatment. Further interest in specific TMEs via the insulin PI3K-pathway in obese women will provide insight into not only novel therapeutic strategies but also preventive strategies against EC.

Wise Management of Ovarian Cancer: On the Cutting Edge

Epithelial ovarian cancer (EOC) is the fifth leading cause of cancer mortality among women. Two-thirds of patients present at advanced stage at diagnosis, and the estimated 5 year survival rate is 20-40%. This heterogeneous group of malignancies has distinguishable etiology and molecular biology. Initially, single-gene sequencing was performed to identify germline DNA variations associated with EOC. However, hereditary EOC syndrome can be explained by germline pathogenic variants (gPVs) in several genes. In this regard, next-generation sequencing (NGS) changed clinical diagnostic testing, allowing assessment of multiple genes simultaneously in a faster and cheaper manner than sequential single gene analysis. As we move into the era of personalized medicine, there is evidence that poly (ADP-ribose) polymerase (PARP) inhibitors exploit homologous recombination (HR) deficiency, especially in breast cancer gene 1 and 2 (BRCA1/2) mutation carriers. Furthermore, extensive preclinical data supported the development of aurora kinase (AURK) inhibitors in specific tumor types, including EOC. Their efficacy may be optimized in combination with chemotherapeutic or other molecular agents. The efficacy of metformin in ovarian cancer prevention is under investigation. Certain mutations, such as ARID1A mutations, and alterations in the phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR pathway, which are specific in ovarian clear cell carcinoma (OCCC) and endometrioid ovarian carcinoma (EnOC), may offer additional therapeutic targets in these clinical entities. Malignant ovarian germ cell tumors (MOGCTs) are rare and randomized trials are extremely challenging for the improvement of the existing management and development of novel strategies. This review attempts to offer an overview of the main aspects of ovarian cancer, catapulted from the molecular mechanisms to therapeutic considerations.

Insulin-PI3K signalling: an evolutionarily insulated metabolic driver of cancer

Cancer is driven by incremental changes that accumulate, eventually leading to oncogenic transformation. Although genetic alterations dominate the way cancer biologists think about oncogenesis, growing evidence suggests that systemic factors (for example, insulin, oestrogen and inflammatory cytokines) and their intracellular pathways activate oncogenic signals and contribute to targetable phenotypes. Systemic factors can have a critical role in both tumour initiation and therapeutic responses as increasingly targeted and personalized therapeutic regimens are used to treat patients with cancer. The endocrine system controls cell growth and metabolism by providing extracellular cues that integrate systemic nutrient status with cellular activities such as proliferation and survival via the production of metabolites and hormones such as insulin. When insulin binds to its receptor, it initiates a sequence of phosphorylation events that lead to activation of the catalytic activity of phosphoinositide 3-kinase (PI3K), a lipid kinase that coordinates the intake and utilization of glucose, and mTOR, a kinase downstream of PI3K that stimulates transcription and translation. When chronically activated, the PI3K pathway can drive malignant transformation. Here, we discuss the insulin-PI3K signalling cascade and emphasize its roles in normal cells (including coordinating cell metabolism and growth), highlighting the features of this network that make it ideal for co-option by cancer cells. Furthermore, we discuss how this signalling network can affect therapeutic responses and how novel metabolic-based strategies might enhance treatment efficacy for cancer.

Using Phosphatidylinositol Phosphorylation as Markers for Hyperglycemic Related Breast Cancer

Studies have suggested that type 2 diabetes (T2D) is associated with a higher incidence of breast cancer and related mortality rates. T2D postmenopausal women have an ~20% increased chance of developing breast cancer, and women with T2D and breast cancer have a 50% increase in mortality compared to breast cancer patients without diabetes. This correlation has been attributed to the general activation of insulin receptor signaling, glucose metabolism, phosphatidylinositol (PI) kinases, and growth pathways. Furthermore, the presence of breast cancer specific PI kinase and/or phosphatase mutations enhance metastatic breast cancer phenotypes. We hypothesized that each of the breast cancer subtypes may have characteristic PI phosphorylation profiles that are changed in T2D conditions. Therefore, we sought to characterize the PI phosphorylation when equilibrated in normal glycemic versus hyperglycemic serum conditions. Our results suggest that hyperglycemia leads to: 1) A reduction in PI3P and PIP3, with increased PI4P that is later converted to PI(3,4)P2 at the cell surface in hormone receptor positive breast cancer; 2) a reduction in PI3P and PI4P with increased PIP3 surface expression in human epidermal growth factor receptor 2-positive (HER2+) breast cancer; and 3) an increase in di- and tri-phosphorylated PIs due to turnover of PI3P in triple negative breast cancer. This study begins to describe some of the crucial changes in PIs that play a role in T2D related breast cancer incidence and metastasis.

SGLT2 inhibition slows tumor growth in mice by reversing hyperinsulinemia

Background

Obesity confers an increased risk and accelerates the progression of multiple tumor types in rodents and humans, including both breast and colon cancer. Because sustained weight loss is rarely achieved, therapeutic approaches to slow or prevent obesity-associated cancer development have been limited, and mechanistic insights as to the obesity-cancer connection have been lacking.

Methods

E0771 breast tumors and MC38 colon tumors were treated in vivo in mice and in vitro with two mechanistically different insulin-lowering agents, a controlled-release mitochondrial protonophore (CRMP) and sodium-glucose cotransporter-2 (SGLT2) inhibitors, and tumor growth and glucose metabolism were assessed. Groups were compared by ANOVA with Bonferroni’s multiple comparisons test.

Results

Dapagliflozin slows tumor growth in two mouse models (E0771 breast cancer and MC38 colon adenocarcinoma) of obesity-associated cancers in vivo, and a mechanistically different insulin-lowering agent, CRMP, also slowed breast tumor growth through its effect to reverse hyperinsulinemia. In both models and with both agents, tumor glucose uptake and oxidation were not constitutively high, but were hormone-responsive. Restoration of hyperinsulinemia by subcutaneous insulin infusion abrogated the effects of both dapagliflozin and CRMP to slow tumor growth.

Conclusions

Taken together, these data demonstrate that hyperinsulinemia per se promotes both breast and colon cancer progression in obese mice, and highlight SGLT2 inhibitors as a clinically available means of slowing obesity-associated tumor growth due to their glucose- and insulin-lowering effects.

Molecular basis for class side effects associated with PI3K/AKT/mTOR pathway inhibitors

Introduction: The phosphatidylinositide 3-kinase/AKT/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway has emerged as an important target in cancer therapy. Numerous PI3K/AKT/mTOR pathway inhibitors are extensively studied; some are used clinically, but most of these drugs are undergoing clinical trials. Potential adverse effects, such as severe hepatotoxicity and pneumonitis, have largely restricted the application and clinical significance of these inhibitors. A summary of mechanisms underlying the adverse effects is not only significant for the development of novel PI3K/AKT/mTOR inhibitors but also beneficial for the optimal use of existing drugs. Areas covered: We report a profile of the adverse effects, which we consider the class effects of PI3K/AKT/mTOR inhibitors. This review also discusses potential molecular toxicological mechanisms of these agents, which might drive future drug discovery. Expert opinion: Severe toxicities associated with PI3K/AKT/mTOR inhibitors hinder their approval and limit long-term clinical application of these drugs. A better understanding regarding PI3K/AKT/mTOR inhibitor-induced toxicities is needed. However, the mechanisms underlying these toxicities remain unclear. Future research should focus on developing strategies to reduce toxicities of approved inhibitors as well as accelerating new drug development. This review will be useful to clinical, pharmaceutical, and toxicological researchers.

Anticancer activity of metformin: a systematic review of the literature

Background

The anticancer activity of metformin has been confirmed against several cancer types in vitro and in vivo. However, the underlying mechanisms of metformin in the treatment of cancer are not fully understood. This systematic review aims to discuss the possible anticancer mechanism of action of metformin.

Method

A search through different databases was conducted, including Medline and EMBASE.

Results

A total of 96 articles were identified of which 56 were removed for duplication and 24 were excluded after reviewing the title and abstract. A total of 12 research articles were included that describe different antiproliferative mechanisms that may contribute to the antineoplastic effects of metformin.

Conclusion

This analysis discussed the potential anticancer activity of metformin and highlighted the importance of AMPK as a potential target for anticancer therapy.

The Mechanism of Phillyrin from the Leaves of Forsythia suspensa for Improving Insulin Resistance

Three lignans, phillyrin, forsythia ester A, and rosin-β-D-furan glucose, were isolated from Forsythia suspensa which is a famous Traditional Chinese Medicine used for clearing heat and detoxifying, reducing swelling and dispersing knot, and dispersing wind heat. In this study, the effects of phillyrin, forsythia ester A, and rosin-β-D-furan glucose on insulin resistance of 3T3-L1 adipocytes were investigated by the method of glucose oxidase-peroxidase (GOD-POD) and the mechanism was assayed by the method of western blot. The results indicated that phillyrin, forsythia ester A, and rosin-β-D-furan glucose could improve the glucose uptake in 3T3-L1 adipocytes under insulin resistance (IR). Among them, phillyrin showed significant activity in increasing glucose consumption at the concentrations of 100 μM and 200 μM (P < 0.001). The mechanism of improving insulin resistance may be that phillyrin could raise the protein phosphorylation of IRS-1 and Akt and the expression levels of GLUT4 protein.

The unconventional role of Akt1 in the advanced cancers and in diabetes-promoted carcinogenesis

Decades of research have elucidated the critical role of Akt isoforms in cancer as pro-tumorigenic and metastatic regulators through their specific effects on the cancer cells, tumor endothelial cells and the stromal cells. The pro-cancerous role of Akt isoforms through enhanced cell proliferation and suppression of apoptosis in cancer cells and the cells in the tumor microenvironment is considered a dogma. Intriguingly, studies also indicate that the Akt pathway is essential to protect the endothelial-barrier and prevent aberrant vascular permeability, which is also integral to tumor perfusion and metastasis. To complicate this further, a flurry of recent reports strongly indicates the metastasis suppressive role of Akt, Akt1 in particular in various cancer types. These reports emanated from different laboratories have elegantly demonstrated the paradoxical effect of Akt1 on cancer cell epithelial-to-mesenchymal transition, invasion, tumor endothelial-barrier disruption, and cancer metastasis. Here, we emphasize on the specific role of Akt1 in mediating tumor cell-vasculature reciprocity during the advanced stages of cancers and discuss how Akt1 differentially regulates cancer metastasis through mechanisms distinct from its pro-tumorigenic effects. Since Akt is integral for insulin signaling, endothelial function, and metabolic regulation, we also attempt to shed some light on the specific effects of diabetes in modulating Akt pathway in the promotion of tumor growth and metastasis.

Cancer-Induced Reprogramming of Host Glucose Metabolism: "Vicious Cycle" Supporting Cancer Progression

Unrestricted cancer growth requires permanent supply of glucose that can be obtained from cancer-mediated reprogramming of glucose metabolism in the cancer-bearing host. The pathological mechanisms by which cancer cells exert their negative influence on host glucose metabolism are largely unknown. This paper proposes a mechanism of metabolic and hormonal changes that may favor glucose delivery to tumor (not host) cells by creating a cancer-host "vicious cycle" whose prolonged action drives cancer progression and promotes host cachexia. To verify this hypothesis, a feedback model of host-cancer interactions that create the "vicious cycle" via cancer-induced reprogramming of host glucose metabolism is proposed. This model is capable of answering some crucial questions as to how anabolic cancer cells can reprogram the systemic glucose metabolism and why these pathways were not observed in pregnancy. The current paper helps to better understanding a pathogenesis of cancer progression and identify hormonal/metabolic targets for anti-cancer treatment.

Dietary Fat and Sugar in Promoting Cancer Development and Progression

The uncontrolled cellular growth that characterizes tumor formation requires a constant delivery of nutrients. Since the 1970s, researchers have wondered if the supply of nutrients from the diet could impact tumor development. Numerous studies have assessed the impact of dietary components, specifically sugar and fat, to increased cancer risk. For the most part, data from these trials have been inconclusive; however, this does not indicate that dietary factors do not contribute to cancer progression. Rather, the dietary contribution may be dependent on tumor, patient, and context, making it difficult to detect in the setting of large trials. In this review, we combine data from prospective cohort trials with mechanistic studies in mice to argue that fat and sugar can play a role in tumorigenesis and disease progression. We find that certain tumors may respond directly to dietary sugar (colorectal and endometrial cancers) and fat (prostate cancer) or indirectly to the obese state (breast cancer).

Alizarin increase glucose uptake through PI3K/Akt signaling and improve alloxan-induced diabetic mice

Aim: Alizarin (AZ), that can be isolated from Rubia cordifolia, has biological activities such as antioxidation and anti-inflammatory. This study aimed to investigate the effect of AZ on glucose and lipid metabolism disorders in alloxan-induced diabetic mice and also explored the effect of AZ on insulin resistance in 3T3-L1 adipocytes. Results: The research showed that AZ could decrease fasting and postprandial blood glucose, TG, TC and MDA, and it could also increase liver glycogen levels and SOD activity in diabetic mice. AZ could significantly improve the glucose uptake of 3T3-L1 adipocytes under insulin resistance, and could also increase GLUT4 protein expression levels, IRS-1 and Akt protein phosphorylation. Conclusion: These results showed that AZ has the potential to reduce blood sugar and improve insulin resistance.

Dioscin attenuates high‑fat diet‑induced insulin resistance of adipose tissue through the IRS‑1/PI3K/Akt signaling pathway

Insulin resistance, as a common metabolic disorder, may be caused by diet‑induced obesity. The aim of the present study is to investigate the effects of dioscin on regulating insulin resistance of adipose tissue induced by a high‑fat diet (HFD). An animal model was established successfully using C57BL/6J mice with high‑fat feeding, followed by treatment with 5, 10 and 20 mg/kg dioscin through gavage for 18 weeks, and randomly divided into a control group, a HFD model group and a dioscin group treated with 5, 10 and 20 mg/kg/day dioscin for 12 weeks. Histopathological changes in adipose tissues were examined using hematoxylin and eosin staining. Biochemical parameters of the serum were also monitored, including glucose, insulin, total triglyceride, homeostasis model assessment of insulin resistance (HOMA‑IR) and adipose insulin resistance (Adipo‑IR) levels. Expression of the mRNA and associated proteins of the insulin receptor substrate 1 (IRS‑1)/phosphoinositide 3‑kinase (PI3K)/protein kinase B (Akt) pathways were determined using reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) and western blot analysis, respectively. HOMA‑IR and Adipo‑IR values of mice fed with a HFD were significantly higher compared with those in the control group (P<0.01). However, dioscin administration significantly decreased HOMA‑IR and Adipo‑IR values in a dose‑dependent manner (P<0.05), suggesting the effects of dioscin on attenuating insulin resistance. RT‑qPCR results indicated that the associated genes of the IRS‑1/PI3K/Akt pathway were significantly downregulated by HFD compared with the control group (P<0.05), while dioscin significantly increased the expression of those genes compared with the control group (P<0.05). Similarly, the significant increase in phosphorylated (p‑)IRS‑1/IRS‑1 (P<0.05) and p‑Akt/Akt (P<0.05) values were substantially reversed by dioscin treatment. Dioscin pronouncedly mitigated insulin resistance in adipose tissues through the IRS‑1/PI3K/Akt pathway and has potential to be used as a novel therapeutic agent for the therapy of HFD‑induced insulin resistance in adipose tissue.

The Impact of Serum Glucose, Anti-Diabetic Agents, and Statin Usage in Non-small Cell Lung Cancer Patients Treated With Definitive Chemoradiation

Introduction: Epidemiologic data indicate diabetes confers an augmented risk of lung cancer development, yet the relationship between hyperglycemia, metabolic agents, and prognosis is unclear. We analyzed the impact of hyperglycemia, anti-diabetic agents, and statins on outcomes in non-small cell lung cancer (NSCLC) patients undergoing chemoradiation.

Method and Materials: In total, data from 170 patients with stage III NSCLC treated at the University of Pittsburgh Medical Center between 2001 and 2014 were obtained for analysis. Kaplan-Meier survival analysis was used to estimate time-to-event for overall survival (OS), disease-free survival, distant metastasis (DM), and loco-regional control (LRC). Blood glucose values (n = 2870), statins, and diabetic medications were assessed both continuously and categorically in univariable and multivariable Cox proportional hazard regression models to estimate hazard ratios and identify prognostic factors.

Results: Tumor volume was a negative prognostic factor for OS, disease-free survival, DM, and LRC (p = 0.001). Tumor stage and treatment time were associated with increased all-cause mortality. Any glucose measurement ≥ 130 mg/dl during treatment (2-year estimate 49.9 vs. 65.8%, p = 0.095) was borderline significant for decreased LRC, with similar trends on multivariable analysis (HR 1.636, p = 0.126) and for OS (HR 1.476, p = 0.130). Statin usage was associated with improved 2-year LRC (53.4 vs. 62.4%, p = 0.088) but not with improvements in survival. Other glycemic parameters, comorbid diabetes diagnosis, or anti-diabetic medications were not significantly associated with outcomes.

Conclusions: There were trends for blood glucose value over 130 mg/dl and statin nonuse being associated with inferior prognosis for LRC in stage III NSCLC patients; glycemic state, statin usage, and glucose-modulating medications were not associated with survival outcomes in multivariable analysis in this retrospective database.

The association of diabetes mellitus and insulin treatment with expression of insulin-related proteins in breast tumors

BACKGROUND

The insulin receptor (INSR) and the insulin growth factor 1 receptor (IGF1R) play important roles in the etiology of both diabetes mellitus and breast cancer. We aimed to evaluate the expression of hormone and insulin-related proteins within or related to the PI3K and MAPK pathway in breast tumors of women with or without diabetes mellitus, treated with or without insulin (analogues).

METHODS

Immunohistochemistry was performed on tumor tissue of 312 women with invasive breast cancer, with or without pre-existing diabetes mellitus, diagnosed in 2000-2010, who were randomly selected from a Danish breast cancer cohort. Women with diabetes were 2:1 frequency matched by year of birth and age at breast cancer diagnosis to those without diabetes. Tumor Microarrays were successfully stained for p-ER, EGFR, p-ERK1/2, p-mTOR, and IGF1R, and scored by a breast pathologist. Associations of expression of these proteins with diabetes, insulin treatment (human insulin and insulin analogues) and other diabetes medication were evaluated by multivariable logistic regression adjusting for menopause and BMI; effect modification by menopausal status, BMI, and ER status was assessed using interactions terms.

RESULTS

We found no significant differences in expression of any of the proteins in breast tumors of women with (n = 211) and without diabetes (n = 101). Among women with diabetes, insulin use (n = 53) was significantly associated with higher tumor protein expression of IGF1R (OR = 2.36; 95%CI:1.02-5.52; p = 0.04) and p-mTOR (OR = 2.35; 95%CI:1.13-4.88; p = 0.02), especially among women treated with insulin analogues. Menopause seemed to modified the association between insulin and IGF1R expression (p = 0.07); the difference in IGF1R expression was only observed in tumors of premenopausal women (OR = 5.10; 95%CI:1.36-19.14; p = 0.02). We found no associations between other types of diabetes medication, such as metformin, and protein expression of the five proteins evaluated.

CONCLUSIONS

In our study, breast tumors of women with pre-existing diabetes did not show an altered expression of selected PI3K/MAPK pathway-related proteins. We observed an association between insulin treatment and increased p-mTOR and IGF1R expression of breast tumors, especially in premenopausal women. This observation, if confirmed, might be clinically relevant since the use of IGF1R and mTOR inhibitors are currently investigated in clinical trials.

SUV calculation in breast cancer: which normalization should be applied when using 18F-FDG PET?

BACKGROUND

When using 18F-FDG PET, glucose metabolism quantification is affected by various factors. We aimed to investigate the benefit of different standardized uptake value (SUV) normalizations to improve the accuracy of 18F-FDG uptake to predict breast cancer aggressiveness and response to treatment.

METHODS

Two hundred fifty-two women with locally advanced breast cancer treated with neoadjuvant chemotherapy (NAC) were included. Women underwent 18F-FDG PET before and after the first course of NAC. Glucose serum levels, patient heights and weights were recorded at the time of each PET exam. Four different procedures for SUV normalization of the primary tumor were used: by body weight (SUVBW) by blood glucose level (SUVG), by lean body mass (SUL) and then corrected for both lean body mass and blood glucose level (SULG).

RESULTS

At baseline, SUL was significantly lower than SUVBW (5.9±4.0 and 9.5±6.5, respectively; P<0.0001), whereas SUVG and SUVBW were not significantly different (9.7±6.4 and 9.5±6.5, respectively; P=0.67). Concerning SUV changes (ΔSUV), the different normalizations methods did not induce significant quantitative differences. The correlation coefficients were high between the four normalizations methods of SUV1, SUV2 and ΔSUVB (R>0.95; P<0.0001). High baseline SUVBW measures were positively correlated with the biological tumor characteristics of aggressiveness and proliferation (P<0.001): ductal carcinoma, high tumor grading, high mitotic activity, negative estrogen receptor status and the TNBC subtype. ΔSUVBW was highly predictive of pCR (AUC=0.76 on ROC curve analysis; P<0.0001). The different SUV normalizations yields identical statistical results and AUC to predict tumor biological aggressiveness and response to therapy.

CONCLUSIONS

In the present setting, SUVBW and SUL can be considered as robust measures and be used in future multicenter trials. The additional normalization of SUV by glycemia involves stringent methodologic procedures to avoid biased risk measurements and offers no statistical advantages.

OP449 inhibits breast cancer growth without adverse metabolic effects

Hyperinsulinemia is associated with a decrease in breast cancer recurrence-free survival and overall survival. Inhibition of insulin receptor signaling is associated with glycemic dysregulation. SET is a direct modulator of PP2A, which negatively regulates the PI3K/AKT/mTOR pathway. OP449, a SET inhibitor, decreases AKT/mTOR activation. The effects of OP449 treatment on breast cancer growth in the setting of pre-diabetes, and its metabolic implications are currently unknown. We found that the volumes and weights of human MDA-MB-231 breast cancer xenografts were greater in hyperinsulinemic mice compared with controls (P < 0.05), and IR phosphorylation was 4.5-fold higher in these mice (P < 0.05). Human and murine breast cancer tumors treated with OP449 were 47% and 39% smaller than controls (P < 0.05, for both, respectively). AKT and S6RP phosphorylation were 82% and 34% lower in OP449-treated tumors compared with controls (P < 0.05, P = 0.06, respectively). AKT and S6RP phosphorylation in response to insulin was 30% and 12% lower in cells, pre-treated with OP449, compared with control cells (P < 0.01, P < 0.05, respectively). However, even with decreased AKT/mTOR activation, body weights and composition, blood glucose and plasma insulin, glucose tolerance, serum triglyceride and cholesterol levels were similar between OP449-treated mice and controls. Xenografts and liver tissue from OP449-treated mice showed a 64% and 70% reduction in STAT5 activation, compared with controls (P < 0.01 and P = 0.06, respectively). Our data support an anti-neoplastic effect of OP449 on human breast cancer cells in vitro and in xenografts in the setting of hyperinsulinemia. OP449 led to the inhibition of AKT/mTOR signaling, albeit, not leading to metabolic derangements.

The PI3K Pathway in Human Disease

Phosphoinositide 3-kinase (PI3K) activity is stimulated by diverse oncogenes and growth factor receptors, and elevated PI3K signaling is considered a hallmark of cancer. Many PI3K pathway-targeted therapies have been tested in oncology trials, resulting in regulatory approval of one isoform-selective inhibitor (idelalisib) for treatment of certain blood cancers and a variety of other agents at different stages of development. In parallel to PI3K research by cancer biologists, investigations in other fields have uncovered exciting and often unpredicted roles for PI3K catalytic and regulatory subunits in normal cell function and in disease. Many of these functions impinge upon oncology by influencing the efficacy and toxicity of PI3K-targeted therapies. Here we provide a perspective on the roles of class I PI3Ks in the regulation of cellular metabolism and in immune system functions, two topics closely intertwined with cancer biology. We also discuss recent progress developing PI3K-targeted therapies for treatment of cancer and other diseases.

Biological Mechanisms for the Effect of Obesity on Cancer Risk: Experimental Evidence

Multiple epidemiological studies demonstrated that overweight and obesity significantly increase the risk of several types of cancer. As the prevalence of obesity is dramatically rising, it is expected that it will represent one of the major lifestyle-associated risk factors for cancer development in the near future. Numerous recent studies expanded knowledge about key players and pathways, which are deregulated in the obese state and potentially promote cancer initiation, progression and aggressiveness via remote and local effects. These players include (but are not limited to) insulin/IGF, adipokines and inflammatory signaling molecules as well as metabolites. Nevertheless, the detailed mechanisms linking obesity and malignant transformation at the systemic, cellular and molecular level still demand further investigation. Additionally, dysfunctional molecular metabolic pathways appear to be specific for distinct cancer entities, thereby yet precluding definition of a common principle. This chapter will present an overview of the current knowledge of molecular nodes linking obesity and cancer and will briefly touch upon potential therapy options addressing metabolic cancer etiologies.

Obesity and Cancer Mechanisms: Cancer Metabolism

Obesity is a risk factor for cancer development and is associated with poor prognosis in multiple tumor types. The positive energy balance linked with obesity induces a variety of systemic changes including altered levels of insulin, insulin-like growth factor-1, leptin, adiponectin, steroid hormones, and cytokines. Each of these factors alters the nutritional milieu and has the potential to create an environment that favors tumor initiation and progression. Although the complete ramifications of obesity as it relates to cancer are still unclear, there is convincing evidence that reducing the magnitude of the systemic hormonal and inflammatory changes has significant clinical benefits. This review will examine the changes that occur in the obese state and review the biologic mechanisms that connect these changes to increased cancer risk. Understanding the metabolic changes that occur in obese individuals may also help to elucidate more effective treatment options for these patients when they develop cancer. Moving forward, targeted clinical trials examining the effects of behavioral modifications such as reduced carbohydrate intake, caloric restriction, structured exercise, and/or pharmacologic interventions such as the use of metformin, in obese populations may help to reduce their cancer risk.

EMT reversal in human cancer cells after IR knockdown in hyperinsulinemic mice

Type 2 diabetes (T2D) is associated with increased cancer risk and cancer-related mortality. Data herein show that we generated an immunodeficient hyperinsulinemic mouse by crossing the Rag1(-/-) mice, which have no mature B or T lymphocytes, with the MKR mouse model of T2D to generate the Rag1(-/-) (Rag/WT) and Rag1(-/-)/MKR(+/+) (Rag/MKR) mice. The female Rag/MKR mice are insulin resistant and have significantly higher nonfasting plasma insulin levels compared with the Rag/WT controls. Therefore, we used these Rag/MKR mice to investigate the role of endogenous hyperinsulinemia on human cancer progression. In this study, we show that hyperinsulinemia in the Rag/MKR mice increases the expression of mesenchymal transcription factors, TWIST1 and ZEB1, and increases the expression of the angiogenesis marker, vascular endothelial growth factor A (VEGFA). We also show that silencing the insulin receptor (IR) in the human LCC6 cancer cells leads to decreased tumor growth and metastases, suppression of mesenchymal markers vimentin, SLUG, TWIST1 and ZEB1, suppression of angiogenesis markers, VEGFA and VEGFD, and re-expression of the epithelial marker, E-cadherin. The data in this paper demonstrate that IR knockdown in primary tumors partially reverses the growth-promoting effects of hyperinsulinemia as well as highlighting the importance of the insulin receptor signaling pathway in cancer progression, and more specifically in epithelial-mesenchymal transition.

A Rat Model to Study the Effects of Diet-Induced Obesity on Radiation-Induced Mammary Carcinogenesis

A detailed understanding of the relationship between radiation-induced breast cancer and obesity is needed for appropriate risk management and to prevent the development of a secondary cancer in patients who have been treated with radiation. Our goal was to develop an animal model to study the relationship by combining two existing Sprague-Dawley rat models of radiation-induced mammary carcinogenesis and diet-induced obesity. Female rats were fed a high-fat diet for 4 weeks and categorized as obesity prone or obesity resistant based on their body weight at 7 weeks of age, at which time the rats were irradiated with 4 Gy. Control rats were fed a standard diet and irradiated at the same time and in the same manner. All rats were maintained on their initial diets and assessed for palpable mammary cancers once a week for the next 30 weeks. The obesity-prone rats were heavier than those in the other groups. The obesity-prone rats were also younger than the other animals at the first detection of mammary carcinomas and their carcinoma weights were greater. A tendency toward higher insulin and leptin blood levels were observed in the obesity-prone rats compared to the other two groups. Blood angiotensin II levels were elevated in the obesity-prone and obesity-resistant rats. Genes related to translation and oxidative phosphorylation were upregulated in the carcinomas of obesity-prone rats. Expression profiles from human breast cancers were used to validate this animal model. As angiotensin is potentially an important factor in obesity-related morbidities and breast cancer, a second set of rats was fed in a similar manner, irradiated and then treated with an angiotensin-receptor blocker, losartan and candesartan. Neither blocker altered mammary carcinogenesis; analyses of losartan-treated animals indicated that expression of renin in the renal cortex and of Agtr1a (angiotensin II receptor, type 1) in cancer tissue was significantly upregulated, suggesting the presence of compensating mechanisms for blocking angiotensin-receptor signaling. Thus, obesity-related elevation of insulin and leptin blood levels and an increase in available energy may facilitate sustained protein synthesis in cancer cells, which is required for rapid cancer development.

Metabolic Syndrome, Type 2 Diabetes, and Cancer: Epidemiology and Potential Mechanisms

Obesity is associated with multiple metabolic disorders that drive cardiovascular disease, T2D and cancer. The doubling in the number of obese adults over the past 3 decades led to the recognition of obesity as a "disease". With over 42 million children obese or overweight, this epidemic is rapidly growing worldwide. Obesity and T2D are both associated together and independently with an increased risk for cancer and a worse prognosis. Accumulating evidence from epidemiological studies revealed potential factors that may explain the association between obesity-linked metabolic disorders and cancer risk. Studies based on the insulin resistance MKR mice, highlighted the roe of the insulin receptor and its downstream signaling proteins in mediating hyperinsulinemia's mitogenic effects. Hypercholesterolemia was also shown to promote the formation of larger tumors and enhancement in metastasis. Furthermore, the conversion of cholesterol into 27-Hydroxycholesterol was found to link high fat diet-induced hypercholesterolemia with cancer pathophysiology. Alteration in circulating adipokines and cytokines are commonly found in obesity and T2D. Adipokines are involved in tumor growth through multiple mechanisms including mTOR, VEGF and cyclins. In addition, adipose tissues are known to recruit and alter macrophage phenotype; these macrophages can promote cancer progression by secreting inflammatory cytokines such as TNF-α and IL-6. Better characterization on the above factors and their downstream effects is required in order to translate the current knowledge into the clinic, but more importantly is to understand which are the key factors that drive cancer in each patient. Until we reach this point, policies and activities toward healthy diets and physical activities remain the best medicine.

Obesity and Diabetes: The Increased Risk of Cancer and Cancer-Related Mortality

Obesity and type 2 diabetes are becoming increasingly prevalent worldwide, and both are associated with an increased incidence and mortality from many cancers. The metabolic abnormalities associated with type 2 diabetes develop many years before the onset of diabetes and, therefore, may be contributing to cancer risk before individuals are aware that they are at risk. Multiple factors potentially contribute to the progression of cancer in obesity and type 2 diabetes, including hyperinsulinemia and insulin-like growth factor I, hyperglycemia, dyslipidemia, adipokines and cytokines, and the gut microbiome. These metabolic changes may contribute directly or indirectly to cancer progression. Intentional weight loss may protect against cancer development, and therapies for diabetes may prove to be effective adjuvant agents in reducing cancer progression. In this review we discuss the current epidemiology, basic science, and clinical data that link obesity, diabetes, and cancer and how treating obesity and type 2 diabetes could also reduce cancer risk and improve outcomes.

Inflammatory cytokine COX-2 mediated cell proliferation through increasing cyclin D1 expression induced by inorganic arsenic in SV-HUC-1 human uroepithelial cells

Inorganic arsenic promotes SV-HUC-1 cells proliferation.

Insulin/Insulin-like growth factors in cancer: new roles for the aryl hydrocarbon receptor, tumor resistance mechanisms, and new blocking strategies

The insulin-like growth factor 1 receptor (IGF1R) and the insulin receptor (IR) are receptor tyrosine kinases that are expressed in cancer cells. The results of different studies indicate that tumor proliferation and survival is dependent on the IGF1R and IR, and that their inhibition leads to reductions in proliferation and increases in cell death. Molecular targeting therapies that have been used in solid tumors include anti-IGF1R antibodies, anti-IGF1/IGF2 antibodies, and small molecule inhibitors that suppress IGF1R and IR kinase activity. New advances in the molecular basis of anti-IGF1R blocking antibodies reveal they are biased agonists and promote the binding of IGF1 to integrin β3 receptors in some cancer cells. Our recent reports indicate that pharmacological aryl hydrocarbon receptor (AHR) ligands inhibit breast cancer cell responses to IGFs, suggesting that targeting AHR may have benefit in cancers whose proliferation and survival are dependent on insulin/IGF signaling. Novel aspects of IGF1R/IR in cancer, such as biased agonism, integrin β3 signaling, AHR, and new therapeutic targeting strategies will be discussed.

mTOR pathway in colorectal cancer: an update

The mammalian target of rapamycin (mTOR) has emerged as a potential target for drug development, particularly due to the fact that it plays such a crucial role in cancer biology. In addition, next-generation mTOR inhibitors have become available, marking an exciting new phase in mTOR-based therapy. However, the verdict on their therapeutic efectiveness remains unclear. Here we review phosphatidylinositol-3-kinase (PI3K)/Akt/mTOR signaling as one of the primary mechanisms for sustaining tumor outgrowth and metastasis, recent advances in the development of mTOR inhibitors, and current studies addressing mTOR activation/inhibition in colorectal cancer (CRC). We will also discuss our recent comparative study of diferent mTOR inhibitors in a population of colon cancer stem cells (CSCs), and current major challenges for achieving individualized drug therapy using kinase inhibitors.

Insulin-like growth factors, insulin, and growth hormone signaling in breast cancer: implications for targeted therapy

OBJECTIVE

In recent decades, multiple therapeutics targeting the estrogen and human epidermal growth factor-2 (HER2) receptors have been approved for the treatment of breast cancer.

METHODS

This review discusses a number of growth factor pathways that have been implicated in resistance to both anti-estrogen and HER2-targeted therapies. The association between growth factors and breast cancer is well established. Over decades, numerous laboratories have studied the link between insulin-like growth factor (IGF), insulin, and growth hormone (GH) to the development and progression of breast cancer.

RESULTS

Although preclinical data demonstrates that blockade of these receptors inhibits breast cancer growth, progression, and drug resistance, therapies targeting the IGF, insulin, and GH receptors (GHRs) have not been successful in producing significant increases in progression-free, disease-free, or overall survival for patients with breast cancer. The failure to demonstrate a benefit of growth factor blockade in clinical trials can be attributed to redundancy in IGF, insulin, and GHR signaling pathways. All 3 receptors are able to activate oncogenic phosphoinositide-3 kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways.

CONCLUSION

Consequently, multitargeted blockade of growth factor receptors and their common downstream kinases will be necessary for the successful treatment of breast cancer.