Targeting Insulin Receptor Research Articles

MiR-27b-5p regulates chicken liver disease via targeting IRS2 to suppress the PI3K/AKT signal pathway

The liver is a vital organ in chickens that performs a number of crucial physiological functions, including the storage of hepatic glycogen, protein synthesis, detoxification, and deoxidation. The growth and metabolism of the liver are complex processes influenced by factors such as environment, diet, and genetics. MicroRNAs (miRNAs), as post-transcriptional regulatory molecules, play a role in various biological processes. There is growing evidence that miR-27b-5p plays a key role in the regulation of liver development and metabolism in various species. However, its role in chicken livers has yet to be determined. In our experiment, we found that chickens with fatty livers had significantly higher levels of serum triglyceride (TG) and total cholesterol (TC) compared to the normal chickens, while the control group had significantly higher levels of very low-density lipoprotein (VLDL) and serum hormones. Further research showed that the mRNA of miR-27b-5p was highly expressed in fatty livers. By exploring the function of miR-27b-5p in chicken livers, we discovered that it promotes lipogenesis, oxidative stress, and inflammatory responses, leading to hepatocyte apoptosis. Our study also established the mechanism by which miR-27b-5p interacts with its target gene, and found that miR-27b-5p targets insulin receptor substrate 2 (IRS2) and modulates the PI3K/AKT signaling pathway. Additionally, our investigation of IRS2 in chicken hepatocytes revealed that knocking down IRS2 has the same effects as overexpressing miR-27b-5p. In conclusion, our study revealed that miR-27b-5p directly binds to IRS2, inhibiting the PI3K/AKT signaling pathway and causing steatosis, oxidative stress, inflammation, and apoptosis in chicken liver.

Retracted] MicroRNA‑766 inhibits papillary thyroid cancer progression by directly targeting insulin receptor substrate2 and regulating the PI3K/Akt pathway.

Following the publication of this paper, it was drawn to the Editors' attention by a concerned reader that various panels showing the data from flow cytometry experiments in Figs.2D,4D and5D, and certain of the tumor images featured in Fig.7A, were strikingly similar to data appearing in different form in other articles by different authors. Furthermore, overlapping data panels were identified within this paper comparing the cell migration assay images between Figs.2C and4F. Owing to the fact that the contentious data in the above article had already been published elsewhere, or were already under consideration for publication, prior to its submission to International Journal of Oncology, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [the original article was published in International Journal of Oncology 54: 315‑325, 2019; DOI: 10.3892/ijo.2018.4615].

MiR-15b mediates the obesity-induced adipocyte insulin resistance by targeting insulin receptor

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Abstract P4-02-01: Targeting insulin receptor in estrogen receptor positive breast cancer

Abstract Obesity and metabolic dysfunction are on the rise in the United States. Hyperinsulinemia, frequently seen in these conditions, correlates with an increased risk of development and mortality from estrogen receptor (ER) positive breast cancer. Expression of components of the insulin and insulin-like growth factor (IGF) family of proteins promote cancer cell growth in vitro, link to shorter progression-free survival, and is associates with an increased risk of metastatic disease and death in breast cancer patients. Previously our lab found that development of resistance to the commonly used ER-targeting drug tamoxifen (Tam) in vitro is associated with a loss of the type I IGF receptor expression with an increased dependence on the homologous insulin receptor (IR). These data argue for targeting IR in breast cancer, but concern has been raised due to the potential of disrupting glucose homeostasis in patients with or without existing metabolic disease. To address this concern, a novel insulin-Fc fusion protein (AKS-130) was developed to lower blood glucose levels without causing clinical hypoglycemia with a potential to target tumor IR. AKS-130 was found to downregulate IR expression in models of colorectal cancer (HCT-116) and malignant melanoma (WM266.4). Further, AKS-130 suppressed xenograft growth in fed and fasted states. We examined if AKS-130 had similar effects on ER positive breast cancer cells. To test the hypothesis that resistance to endocrine therapy increases the reliance of ER positive breast cancer cells on IR signaling, we utilized the ER positive breast cancer cell lines (MCF-7L, T47D) and their Tam resistant derivatives (MCF-7L TamR, T47D TamR). Similar to in HCT-116 and WM266.4 cells, we found that AKS-130 is a modest agonist of IR in ER+ breast cancer cells. Exposure to AKS-130 led to a marked reduction in IR expression in both parental and TamR cell lines, and was associated with partially suppressed downstream signaling to Akt. Interestingly, AKS130 induced IR downregulation was inhibited by pretreatment of BMS 536924, a dual IGF1R/IR kinase inhibitor. In vivo, AKS-130 treatment by itself scaled down MCF7L parental xenograft growth as compared to vehicle group, and AKS-130 in combination with Tam trended toward extending time to a tumor size of 500mm3. In MCF7L TamR xenografts, addition of AKS-130 to Tam treatment also trended toward delaying xenograft growth, though it was not statistically significant. Importantly, prolonged treatment with AKS-130 did not lead to significant changes in weight or blood glucose. Taken together these data show that novel agents, such as AKS-130, may serve as way to disrupt IR signaling in cancer cells without affecting host glucose metabolism. Addition of AKS-130 to Tam treatment trended toward delaying xenograft growth though further studies are needed, especially animal model systems of insulin resistance. These data indicate that IR signaling may represent a target to overcome or delay endocrine therapy resistance in breast cancer. Citation Format: Jingran Cao, Lynsey M. Fettig, Kelly LaPara, Xihong Zhang, Sylaja Murikipudi, Andrea R. Delpero, Thomas M. Lancaster, Todd C. Zion, Douglas Yee. Targeting insulin receptor in estrogen receptor positive breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-02-01.

Development of Botanical Pesticides: Exploration on the Phenotype of Vestigial Wings of Insect Pests Induced by Plant Natural Products or Their Derivatives by Blocking Tyrosine Phosphorylation of Insulin Receptor 1

Unlike faster-acting conventional insecticides, some botanical insecticides exhibit growth inhibitory activity against some insect pests. One of the distinguishing features of growth inhibitory activity appears to be in malformed moths with vestigial wings. However, the molecular mechanism underlying vestigial wings of insect pests induced by plant natural products or their derivatives is still elusive. In this work, based upon the phenotype of the vestigial wings of Mythimna separata Walker (as a model pest) induced by a podophyllotoxin derivative 2a (as a model compound), we found that compound 2a not only resulted in 22.1% of malformed moths with vestigial wings but also significantly decreased the fecundity of vestigial-winged female moths in the P generation; the trait of vestigial wings caused by 2a in the P generation can be inherited by the F1 generation; compound 2a may target insulin receptor 1 (InR1), suppress the InR1 mRNA level, and block InR1-pY1229 and InR1-pY1233/1234 phosphorylation levels in a tissue-specific manner "head/thorax/wing tissues". Notably, compound 2a can also induce the vestigial wings of Spodoptera frugiperda (another seriously harmful migratory lepidoptera pest). It is noteworthy that this insect insulin receptor can be used as a new kind of target receptors for the design of novel green insecticides.

Camel Milk Targeting Insulin Receptor-Toward Understanding the Antidiabetic Effects of Camel Milk.

Camel milk (CM) is known for its beneficial virtues in the human diet and health. This includes its antidiabetic properties demonstrated in many in vitro and in vivo studies. Nevertheless, the scientific rationale behind the molecular and cellular basis of such beneficial effects and the exact antidiabetic agent(s)/mechanism(s) are still elusive. In this review, we focused on the recent advances supporting the targeting of insulin receptor (IR) by CM components. Indeed, our recent work reported that CM proteins and derived peptides pharmacologically target IR in vitro leading to its activation and potentiation of insulin-mediated responses. The review describes the experimental approaches used to investigate the effects of CM on IR in vitro based on the fractionation of CM whey proteins to purify functional proteins and their hydrolysis by gastric proteases to generate bioactive peptides. In addition, we illustrated our cellular and molecular model consisting of studying the functional activity of CM fractions on IR and its downstream signaling pathways in the hepatocarcinoma (HepG2) and the human embryonic kidney (HEK293) cells using the bioluminescence resonance energy transfer (BRET), phosphorylation, and glucose uptake assays. Overall, our work demonstrated for the first time that CM lactoferrin and CM-derived bioactive peptides positively modulate IR and its related signaling pathways in HepG2 and HEK293 cells. As a conclusion, the pharmacological targeting of IR by CM sheds more light on the antidiabetic properties of CM by providing its molecular basis that may constitute a solid rationale for the development of new generation of antidiabetic tools from CM-derived proteins and peptides and the utilization of CM in the management of diabetes. The sequencing and the synthesis of the potent bioactive CM peptides may open promising perspectives for their application as antidiabetic agents.

Methyl ferulic acid ameliorates alcohol-induced hepatic insulin resistance via miR-378b-mediated activation of PI3K-AKT pathway.

A previous study indicated that microRNA-378b (miR-378b) plays a critical role in controlling hepatic insulin resistance by targeting insulin receptor (IR) and p110α in alcoholic liver disease (ALD). Methyl ferulic acid (MFA), a bioactive ingredient in Securidaca inappendiculata Hassk rhizomes, exhibits multiple pharmacological activities. It has been reported that MFA ameliorates insulin resistance in ALD, whereas the underlying molecular mechanism remains unclear. The objective of study was to evaluate the influence of MFA on insulin sensitivity in ethanol-induced L-02 cells as well as alcohol-fed mice and illuminate the function of miR-378b-mediated phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway in system. MFA was found to remarkably down-regulate miR-378b level and increase IR and p110α expressions. Furthermore, the effect of MFA on modulating miR-378b/PI3K-AKT pathway to enhance insulin sensitivity was corroborated by overexpressing and inhibiting miR-378b. Taken together, MFA exhibited a positive effect against ALD by attenuating the inhibition of miR-378b on IR/p110α and partly activating the insulin signaling to alleviate alcohol-induced hepatic insulin resistance.

Hypothalamic miR-1983 Targets Insulin Receptor β and the Insulin-mediated miR-1983 Increase Is Blocked by Metformin.

MicroRNAs (miRNAs) expressed in the hypothalamus are capable of regulating energy balance and peripheral metabolism by inhibiting translation of target messenger RNAs (mRNAs). Hypothalamic insulin resistance is known to precede that in the periphery, thus a critical unanswered question is whether central insulin resistance creates a specific hypothalamic miRNA signature that can be identified and targeted. Here we show that miR-1983, a unique miRNA, is upregulated in vitro in 2 insulin-resistant immortalized hypothalamic neuronal neuropeptide Y-expressing models, and in vivo in hyperinsulinemic mice, with a concomitant decrease of insulin receptor β subunit protein, a target of miR-1983. Importantly, we demonstrate that miR-1983 is detectable in human blood serum and that its levels significantly correlate with blood insulin and the homeostatic model assessment of insulin resistance. Levels of miR-1983 are normalized with metformin exposure in mouse hypothalamic neuronal cell culture. Our findings provide evidence for miR-1983 as a unique biomarker of cellular insulin resistance, and a potential therapeutic target for prevention of human metabolic disease.

Abstract PO-056: Insulin receptor signaling in pancreatic acinar cells contributes to pancreatic cancer development

Abstract Hyperinsulinemia is a cardinal feature shared by both obesity and type 2 diabetes, and is independently associated with increased risk of pancreatic ductal adenocarcinoma (PDAC). We previously showed a ~50% reduction in pancreatic intraepithelial neoplasia (PanIN) pre-cancerous lesions in mice with genetically reduced insulin production. Our single-cell transcriptomic data suggested that many pancreatic cell types could mediate the effects of local hyperinsulinemia on PanIN development. In pancreatic acinar cells from mice with reduced insulin, we found alterations in the PI3K/AKT/mTOR and MAPK/ERK pathways known to be involved in tumorigenesis. Here, we examined whether hyperinsulinemia contributes to PDAC development directly through insulin receptor signaling in KrasG12D expressing pancreatic acinar cells. To test this hypothesis, we generated Ptf1aCreER;LSL-KrasG12D;nTnG mice with an Insrwt/wt (PK-Insrwt/wt), Insrwt/fl (PK-Insrwt/fl), or Insrfl/fl (PK-Insrfl/fl) genotype to reduce insulin receptor signaling by 0%, 50%, or 100% in acinar cells, in both males and females. We fed the mice with high-fat diet (HFD) to induce systemic hyperinsulinemia and tracked body weight, fasting glucose and fasting insulin levels routinely. We euthanized the mice when they were 10 months old and performed blinded histopathological analysis and immunohistochemistry staining of the pancreatic sections to assess the PanIN formation. Loss of insulin receptors from acinar cells did not significantly influence body weight, fasting glucose or fasting insulin levels. Alcian blue staining of mucins contained within low-grade PanINs showed that there was a significant reduction in these pre-cancerous lesions in PK-Insrwt/fl and PK-Insrfl/fl female mice compared to PK-Insrwt/wt mice and the difference was Insr gene dosage-dependent. By performing immunohistochemical staining of CK19, marking duct and duct-like cells, we found there was a significant reduction of CK19+ area in PK-Insrwt/fl and PK-Insrfl/fl mice compared to PK-Insrwt/wt mice, and the reduction was Insr gene dosage-dependent. Finally, we found a significant increase in retention of normal acinar cells in PK-Insrfl/fl mice compared to PK-Insrwt/wt mice, which indicates the mice losing Insr had more wild-type like pancreas. Collectively, these data strongly suggest that insulin receptor signaling in acinar cells is important for the metaplasia formation, but do not exclude a role of Insr on other local or distant cell types. Prophylactic approaches targeting insulin receptor signaling pathways, or hyperinsulinemia itself, may be beneficial in preventing pancreatic cancer. Citation Format: Anni M. Y. Zhang, Jenny C. C. Yang, Twan J. J. de Winter, David F. Schaeffer, Janel L. Kopp, James D. Johnson. Insulin receptor signaling in pancreatic acinar cells contributes to pancreatic cancer development [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-056.

Procyanidin B1 and p‐Coumaric Acid from Highland Barley Grain Showed Synergistic Effect on Modulating Glucose Metabolism via IRS‐1/PI3K/Akt Pathway

Phenolic extract in highland barley grain has showed hypoglycemic effect, while little information is available about the active compounds and whether there exist additive or synergistic effect on modulating glucose metabolism. Procyanidin B1 (PB) and p-coumaric acid (CA) are the active compounds in highland barley grain and show synergistic effect on improving glucose uptake and glycogen synthesis by upregulating glucose transporter (GLUT4) and downregulating glycogen synthase kinase-3β (GSK-3β) protein expression, respectively. The mechanism may be attributed to target insulin receptor (IRβ) and regulate insulin receptor substrate-1 (IRS-1)/phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (Akt) pathway. Furthermore, PB + CA exhibits synergistic effect on restoring glucose intolerance and insulin resistance, and improving hepatic glycogen synthesis in impaired glucose tolerance (IGT) mice. The postprandial blood glucose (PBG), homeostasis model assessment (HOMA)-IR values and serum insulin contents in PB + CA-treated IGT mice with dosage of 300mg kg-1 BW are reversed to normal levels. Additionally, PC + CA shows additive effect on inhibiting gluconeogenesis in vitro and in vivo. PB + CA in highland barley grain synergistically modulate glucose metabolism. These results may provide evidence of whole highland barley grain diet achieve superior effect on restoring IGT than isolated components.

MicroRNA-126 inhibits the migration and invasion of endometrial cancer cells by targeting insulin receptor substrate 1.

[This retracts the article DOI: 10.3892/ol.2015.4001.].

MiR-7a Targets Insulin Receptor Substrate-2 Gene and Suppresses Viability and Invasion of Cells in Diabetic Retinopathy Mice via PI3K-Akt-VEGF Pathway.

IntroductionDiabetic retinopathy (DR) is one of the major leading causes for vision loss globally. Current study illustrates the role of miR-7a in DR.Material and MethodsRetinal pericytes (RPs) and Endothelial cells (ECs) were isolated from mouse model of DR. qRT-PCR was done for expression of miR-7a and target gene mRNA, Western blot for protein expression. Identification of miR-7a target gene was done by TargetScan and Luciferase assay. Cell viability and invasion was done by MTT and Transwell chamber assay.ResultsThe expression of miR-7a was down-regulated whereas level of IRS-2 was unregulated in isolated RPs and ECs. Luciferase assay suggested correlation between miR-7a and IRS-2, over-expression of miR-7a using a mimic resulted in suppression in viability and invasion capacity of RPs and ECs and inhibited the protein levels of PI3K/Akt cascade and IRS-2, and however the inhibitor reversed them respectively. Transfection of siRNA targeting IRS-2 caused alteration in miR-7a mediated changes in ECs suggesting that miR-7a may decrease angiogenesis in DR by inhibiting the levels of IRS-2.ConclusionmiR-7a suppresses PI3K/Akt cascade via targeting IRS-2, thus decreasing the viability and invasion capacity of RPs and ECs, suggesting an interesting treatment target for DR.

Pregnancies Complicated by Diabetes, Hypertension and Hypothyroidism: Role of Insulin Resistance

During recent times we are dealing with multiple medical complications occurring in a single pregnant woman. It is well known fact that insulin resistance is present during normal pregnancy and it is relatively diabetogenic state. In women with genetic predisposition, diabetes, hypertension and hypothyroidism complicate pregnancy resulting in increased maternal and perinatal morbidity and mortality. There was evidence in the literature regarding insulin resistance and gestational diabetes. This review analysed the literature regarding the association of diabetes, hypertension and hypothyroidism and found that there is a linkage between these three disorders in pregnant state and the insulin resistance develops by multiple molecular mechanisms both centrally and in peripheral tissues. The key mechanism is insulin receptor substrate-1 (IRS-1) which gets inactivated by serine phosphorylation and leads to hyperglycaemia which in turn leads to stimulation of beta cells of pancreas and leads to hyperinsulinaemia. Pancreas has thyroid hormone receptors and this stimulates the secretion of insulin leading hyperinsulinaemia. Hyperglycaemia leading to increase in free fatty acids and together with proinflammatory factors and reactive oxygen species causes endothelial dysfunction and hypertension. More studies are necessary to target insulin receptor to increase insulin sensitivity and prevent these disorders occurring together.

Insulin receptor substrate 1, but not IRS2, plays a dominant role in regulating pancreatic alpha cell function in mice

Dysregulated glucagon secretion deteriorates glycemic control in type 1 and type 2 diabetes. Although insulin is known to regulate glucagon secretion via its cognate receptor (insulin receptor, INSR) in pancreatic alpha cells, the role of downstream proteins and signaling pathways underlying insulin’s activities are not fully defined. Using in vivo (knockout) and in vitro (knockdown) studies targeting insulin receptor substrate (IRS) proteins, we compared the relative roles of IRS1 and IRS2 in regulating alpha cell function. Alpha cell–specific IRS1-knockout mice exhibited glucose intolerance and inappropriate glucagon suppression during glucose tolerance tests. In contrast, alpha cell–specific IRS2-knockout animals manifested normal glucose tolerance and suppression of glucagon secretion after glucose administration. Alpha cell lines with stable IRS1 knockdown could not repress glucagon mRNA expression and exhibited a reduction in phosphorylation of AKT Ser/Thr kinase (AKT, at Ser-473 and Thr-308). AlphaIRS1KD cells also displayed suppressed global protein translation, including reduced glucagon expression, impaired cytoplasmic Ca2+ response, and mitochondrial dysfunction. This was supported by the identification of novel IRS1-specific downstream target genes, Trpc3 and Cartpt, that are associated with glucagon regulation in alpha cells. These results provide evidence that IRS1, rather than IRS2, is a dominant regulator of pancreatic alpha cell function.

AAV vectors engineered to target insulin receptor greatly enhance intramuscular gene delivery

Adeno-associated virus (AAV) is one of the most commonly used vectors for gene therapy, and the applications for AAV-delivered therapies are numerous. However, the current state of technology is limited by the low efficiency with which most AAV vectors transduce skeletal muscle tissue. We demonstrate that vector efficiency can be enhanced by modifying the AAV capsid with a peptide that binds a receptor highly expressed in muscle tissue. When an insulin-mimetic peptide, S519, previously characterized for its high affinity to insulin receptor (IR), was inserted into the capsid, the AAV9 transduction efficiency of IR-expressing cell lines as well as differentiated primary human muscle cells was dramatically enhanced. This vector also exhibited efficient transduction of mouse muscle in vivo, resulting in up to 18-fold enhancement over AAV9. Owing to its superior transduction efficiency in skeletal muscle, we named this vector “enhanced AAV9” (eAAV9). We also found that the modification enhanced the transduction efficiency of several other AAV serotypes. Together, these data show that AAV transduction of skeletal muscle can be improved by targeting IR. They also show the broad utility of this modular strategy and suggest that it could also be applied to next-generation vectors that have yet to be engineered.

Bovine Milk Exosome and miRNA-2478 Enhances Insulin Sensitivity by Upregulating Insulin Receptor and Promotes Glycogen Synthesis in HepG2 Cells

Background: Milk and milk products are a sort of mandatory component of diet world-wide. Milk exosome and its bioactive content especially miRNA has been linked with several metabolic regulatory pathways and diseases. However, there is lack of convincing experimental validation. Recently, we have profiled cow milk exosomal miRNAs and in silico analysis identified insulin receptor (INSR) as potential target of miRNA-2478 which one of the candidate miRNA is encapsulated in cow milk exosomes. Down-regulation of insulin receptor (INSR) in peripheral tissues including liver results in the development of pathogenesis of Type II diabetes. However, role of miRNA-2478 in regulation of insulin signaling has not been studied so far. The main aim of the study was to decipher the role of milk exosomal miR-2478 on its target insulin receptor in HepG2 cells. Methods: The effect of miR-2478 mimic on INSR mRNA and protein expression, glycogen content and enrichment of RNA polymerase II at insulin gene promoter in HepG2 cells was analysed. Findings: Results of the current study showed that there was increased expression of insulin receptor gene at both mRNA and protein level with increased abundance of bta-miR-2478 in HepG2 cells. Similarly, glycogen content was also found to be increased in bta-miR-2478 transfected cells. Results of ChIP assay also showed enrichment of RNA polymerase on insulin receptor promoter in miR-2478 transfected cells as compared to control. Interpretation: In conclusion, bovine milk exosomes and miR-2478 enhanced insulin sensitivity through increased expression of insulin receptor and glycogen synthesis in HepG2 cells. Funding Statement: None. Declaration of Interests: All authors declare they have no conflict of interest. Ethics Approval Statement: Cow (Sahiwal) milk was collected from the healthy and early lactating animals of ICAR-National Dairy Research Institute, Karnal as per the Institute Animal Ethics Guidelines.

Coumarin-chalcone hybrids targeting insulin receptor: Design, synthesis, anti-diabetic activity, and molecular docking

Four series of thirteen new coumarin-chalcone hybrids (DPCU 1–13, DPCT 1–13, DCCU 1–13 and DCCT 1–13) were designed and synthesized using Biginelli synthesis, Pechmann condensation, Acetylation, and Claisen-Schmidt reactions. Synthesized compounds were tested for insulin receptor in silico docking studies (PDB ID: 1IR3); DCCU 13 and DCCT 13 derivatives received the lowest docking score; Streptozocin (STZ) and Nicotinamide (NA) induced type II diabetes was tested for their anti-diabetic activity in rats. In vivo tests suggested that fasting blood glucose levels of animals treated with DCCU 13 (30 mg/kg body weight) and DCCT 13 (30 mg/kg body weight) were significantly and moderately suppressed, respectively, relative to fasting blood glucose levels of diabetic control animals. Similarly, therapy with DCCU 13 and DCCT 13 attenuated oxidative stress parameters such as lipid peroxidation (MDA), superoxide dismutase (SOD) and increased the glutathione (GSH) in the liver and pancreas in a dose-dependent manner. In comparison, therapy with DCCU 13 (30 mg/kg body weight) mitigated alterations in the histological architecture of the liver and pancreatic tissue. These results indicated that the hybrids DUUC 13 and DCCT 13 at 30 mg/kg had an anti-hyperglycemic and antioxidant impact on STZ + NA mediated type II diabetes in rats. Further detailed work could be required to determine the precise mode of action of the anti-diabetic behavior of hybrids.

MiR-378b Regulates Insulin Sensitivity by Targeting Insulin Receptor and p110α in Alcohol-Induced Hepatic Steatosis.

Insulin resistance has been implicated in alcoholic liver disease. A previous study has shown that microRNAs (miRNAs) play a major role in the production, secretion, and function of insulin. MiRNAs are capable of repressing multiple target genes that in turn negatively regulate various physiological and pathological activities. However, current information on the biological function of miRNAs in insulin resistance is limited. The goal of the present study was to elucidate the role of miR-378b in alcohol-induced hepatic insulin resistance and its underlying mechanism. This study has observed that miR-378b is up-regulated in National Institute on Alcohol Abuse and Alcoholism (NIAAA) alcoholic mouse models as well as in ethanol-induced L-02 cells in vitro. Furthermore, miR-378b overexpression impaired the insulin signaling pathway, and inhibition of miR-378b improved insulin sensitivity in vivo and in vitro. A mechanistic study revealed that IR and p110α are direct targets of miR-378b. Together, these results suggest that miR-378b controls insulin sensitivity by targeting the insulin receptor (IR) as well as p110α and possibly play an inhibitory role in the development of insulin resistance, thereby providing insights into the development of novel diagnostic and treatment methods.

Abstract P1-21-05: A novel long-acting insulin for cancer therapy reduces xenograft tumor growth

Abstract A link between obesity, metabolic dysfunction, and an increased risk in cancer mortality has been well established in several cancer types including, breast, colon, pancreatic, and prostate cancers. A likely mechanism driving this elevated risk is the associated increase in circulating insulin and insulin-like growth factor (IGF), which are known promoters of cancer growth and have been linked to shorter progression-free survival, and increased risk of metastatic disease and death in breast cancer patients. IGF receptor (IGF1R) targeting has been unsuccessful as insulin receptor (IR) also is functional in breast cancers. To address IR targeting, Akston Biosciences developed a novel insulin-Fc fusion protein (AKS-130) with the goal of lowering patient blood glucose levels without causing clinical hypoglycemia. AKS-130 was also found to downregulate IR expression in models of colon cancer (HCT-116) and malignant melanoma (WM266.4). Further, AKS-130 suppressed xenograft growth in fed and fasted states. We examined if AKS-130 had similar effects on estrogen receptor (ER) positive breast cancer cells as ER+ breast cancers may have elevated expression or activation of IGF1R and IR. Data from our lab show that development of endocrine therapy resistance in ER+ breast cancer cell lines is associated with loss of IGF1R expression and subsequently increased sensitivity to insulin signaling, which supports overlapping pro-tumorigenic signaling pathways to IGF1R. To test the hypothesis that resistance to endocrine therapy increases the reliance of ER+ breast cancer cells on IR signaling, we used the ER+ breast cancer cell line, MCF-7L, and a Tam resistant derivative, MCF-7L TamR, to assess IR/IGF1R activation and growth in response to AKS-130. Similar to HCT-116 and WM266.4 cells, MCF-7L parental and TamR cells showed that AKS-130 was an agonist of IR. But after 72 hours of exposure, a marked reduction in IR was seen and associated with partially suppressed downstream signaling to Akt. Interestingly, AKS-130 induced proliferation at similar levels to insulin treatment in MCF-7L parental cells at three and five days post treatment. However, pre-treatment of cells with AKS-130 suppressed further insulin-stimulated growth in MCF-7L TamR cells. Ongoing studies are evaluating the effects of AKS-130 on ER+ breast cancer xenografts in vivo to determine if the ability of the drug to downregulate IR expression results in decreased tumor growth. Taken together these data show that novel agents, such as AKS-130, can target IR function in cancer cells. AKS-130 is a drug which may serve as way to disrupt IR in cancer cells without affecting host glucose metabolism. Targeting of IR signaling may represent a new strategy to overcome endocrine therapy resistance in breast cancer. Citation Format: Lynsey M Fettig, Xihong Zhang, Kelly LaPara, Sylaja Murikipudi, Andrea R Delpero, Thomas M Lancaster, Todd C Zion, Douglas Yee. A novel long-acting insulin for cancer therapy reduces xenograft tumor growth [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-21-05.

Dual-specificity tyrosine phosphorylation-regulated kinase 1A ameliorates insulin resistance in neurons by up-regulating IRS-1 expression

Insulin resistance in the brain is a pathological mechanism that is shared between Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM). Although aberrant expression and phosphorylation of insulin receptor substrate 1 (IRS-1) contribute to insulin resistance, the underlying mechanism remains elusive. In this study, we used several approaches, including adeno-associated virus-based protein overexpression, immunoblotting, immunoprecipitation, immunohistochemistry, and in situ proximal ligation assays, to investigate the function of dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) in IRS-1 regulation and the downstream insulin signaling in neurons. We found that DYRK1A overexpression up-regulated IRS-1 expression by slowing turnover of the IRS-1 protein. We further observed that DYRK1A directly interacted with IRS-1 and phosphorylated IRS-1's multiple serine residues. Of note, DYRK1A and IRS-1 were coordinately up-regulated in the prefrontal cortex of db/db mice brain. Furthermore, DYRK1A overexpression ameliorated chronic high insulin-induced insulin resistance in SH-SY5Y cells as well as in primary rat neurons. These findings suggest that DYRK1A protects against insulin resistance in the brain by elevating IRS-1 expression.