Differential Expression of IR-A, IR-B and IGF-1R in Endometrial Physiology and Distinct Signature in Adenocarcinoma

Diabetes mellitus complications associated with recurrence of stage I endometrioid endometrial cancer: A single-center retrospective study

OBJECTIVE

Identifying clinical features that are associated with recurrence of endometrioid endometrial carcinoma (EEC) in patients with diabetes mellitus (DM).

METHODS

A single-center retrospective cohort study was performed on patients with a diagnosis of both DM and Stage I EEC. Clinical and pathologic features were analyzed in relation to 5-year progression free survival (PFS). Kaplan-Meier Curves and Cox proportional hazard ratios were utilized to assess effect on 5-year PFS.

RESULTS

A total of 539 patients were included, with biopsy proven recurrence in 86 (18 %), and 456 (82 %) with no evidence of recurrence. Age, BMI, HgbA1c, metformin use, number of antihyperglycemic medications, use of adjuvant radiation, and surgical approach were not associated with differences in PFS. Presence of end-organ complications associated with diabetes was correlated with worse PFS (HR 1.78, 95 % CI 1.1-2.9, P = 0.02), and specifically diabetic neuropathy was associated with higher rates of recurrence (HR 3.6, 95 % CI 2.1-6.2, P < 0.01). In this cohort, PFS was independently associated with extent of myoinvasion (HR 2.33, 95 % CI 1.4-3.7, P < 0.01) as well as both microsatellite instability (HR 3.43, 95 % CI 1.8-6.6, P < 0.01), and no specific molecular profile (HR 0.3, 95 % CI 0.2-0.6, P < 0.01) molecular subtypes.

CONCLUSIONS

In patients with DM and EEC, extent of myoinvasion and TCGA molecular subtype correlated with worse PFS. Control of DM as evidenced by HgbA1c, BMI, and use of antihyperglycemic medications did not correlate with PFS in our cohort of patients with Stage I EEC, while the presence of diabetic neuropathy was associated with a higher risk of recurrence. These results highlight importance of evaluating diabetes severity and molecular subtype in endometrial cancer patients.

Long-range repression by ecdysone receptor on complex enhancers of the insulin receptor gene

The insulin signalling pathway is evolutionarily conserved throughout metazoans, playing key roles in development, growth, and metabolism. Misregulation of this pathway is associated with a multitude of disease states including diabetes, cancer, and neurodegeneration. The human insulin receptor gene (INSR) is widely expressed throughout development and was previously described as a 'housekeeping' gene. Yet, there is abundant evidence that this gene is expressed in a cell-type specific manner, with dynamic regulation in response to environmental signals. The Drosophila insulin-like receptor gene (InR) is homologous to the human INSR gene and was previously shown to be regulated by multiple transcriptional elements located primarily within the introns of the gene. These elements were roughly defined in ~1.5 kbp segments, but we lack an understanding of the potential detailed mechanisms of their regulation. We characterized the substructure of these cis-regulatory elements in Drosophila S2 cells, focusing on regulation through the ecdysone receptor (EcR) and the dFOXO transcription factor. By identifying specific locations of activators and repressors within 300 bp subelements, we show that some previously identified enhancers consist of relatively compact clusters of activators, while others have a distributed architecture not amenable to further reduction. In addition, these assays uncovered a long-range repressive action of unliganded EcR. The complex transcriptional circuitry likely endows InR with a highly flexible and tissue-specific response to tune insulin signalling. Further studies will provide insights to demonstrate the impact of natural variation in this gene's regulation, applicable to human genetic studies.

Insulin Receptor Isoforms and Insulin Growth Factor-like Receptors: Implications in Cell Signaling, Carcinogenesis, and Chemoresistance

This comprehensive review thoroughly explores the intricate involvement of insulin receptor (IR) isoforms and insulin-like growth factor receptors (IGFRs) in the context of the insulin and insulin-like growth factor (IGF) signaling (IIS) pathway. This elaborate system encompasses ligands, receptors, and binding proteins, giving rise to a wide array of functions, including aspects such as carcinogenesis and chemoresistance. Detailed genetic analysis of IR and IGFR structures highlights their distinct isoforms, which arise from alternative splicing and exhibit diverse affinities for ligands. Notably, the overexpression of the IR-A isoform is linked to cancer stemness, tumor development, and resistance to targeted therapies. Similarly, elevated IGFR expression accelerates tumor progression and fosters chemoresistance. The review underscores the intricate interplay between IRs and IGFRs, contributing to resistance against anti-IGFR drugs. Consequently, the dual targeting of both receptors could present a more effective strategy for surmounting chemoresistance. To conclude, this review brings to light the pivotal roles played by IRs and IGFRs in cellular signaling, carcinogenesis, and therapy resistance. By precisely modulating these receptors and their complex signaling pathways, the potential emerges for developing enhanced anti-cancer interventions, ultimately leading to improved patient outcomes.

Long-range repression by ecdysone receptor on complex enhancers of the insulin receptor gene

The insulin signaling pathway is evolutionarily conserved throughout metazoans, playing key roles in development, growth, and metabolism. Misregulation of this pathway is associated with a multitude of disease states including diabetes, cancer, and neurodegeneration. Genome-wide association studies indicate that natural variants in putative intronic regulatory elements of the human insulin receptor gene ( INSR) are associated with metabolic conditions, however, this gene's transcriptional regulation remains incompletely studied. INSR is widely expressed throughout development and was previously described as a 'housekeeping' gene. Yet, there is abundant evidence that this gene is expressed in a cell-type specific manner, with dynamic regulation in response to environmental signals. The Drosophila insulin-like receptor gene ( InR ) is homologous to the human INSR gene and was previously shown to be regulated by multiple transcriptional elements located primarily within the introns of the gene. These elements were roughly defined in ∼1.5 kbp segments, but we lack an understanding of the potential detailed mechanisms of their regulation, as well as the integrative output of the battery of enhancers in the entire locus. Using luciferase assays, we characterized the substructure of these cis-regulatory elements in Drosophila S2 cells, focusing on regulation through the ecdysone receptor (EcR) and the dFOXO transcription factor. The direct action of EcR on Enhancer 2 reveals a bimodal form of regulation, with active repression in the absence of the ligand, and positive activation in the presence of 20E. By identifying the location of activators of this enhancer, we characterized a long-range of repression acting over at least 475 bp, similar to the action of long-range repressors found in the embryo. dFOXO and 20E have contrasting effects on some of the individual regulatory elements, and for the adjacent enhancers 2 and 3, their influence was/was not found to be additive, indicating that enhancer action on this locus can/cannot be characterized in part by additive models. Other characterized enhancers from within this locus exhibited "distributed" or "localized" modes of action, suggesting that predicting the joint functional output of multiple regulatory regions will require a deeper experimental characterization. The noncoding intronic regions of InR have demonstrated dynamic regulation of expression and cell type specificity. This complex transcriptional circuitry goes beyond the simple conception of a 'housekeeping' gene. Further studies are aimed at identifying how these elements work together in vivo to generate finely tuned expression in tissue- and temporal-specific manners, to provide a guide to understanding the impact of natural variation in this gene's regulation, applicable to human genetic studies.

Glucose and Cell Context-Dependent Impact of BMI-1 Inhibitor PTC-209 on AKT Pathway in Endometrial Cancer Cells

PURPOSE

In our study, the glucose and cell context-dependent impact of the BMI-1 inhibitor PTC-209 on the AKT pathway in endometrial cancer cells was determined.

METHODS

The expression of BMI-1 was inhibited by PTC-209 in endometrial cancer cells HEC-1A and Ishikawa stimulated with insulin and grown in different glucose concentrations. The migration, invasion, viability, and proliferative potential after PTC-209 treatment was assessed using wound-healing, Transwell assay, Matrigel-coated inserts, and MTT tests. Chromatin immunoprecipitation was used to determine the localization of BMI-1 protein at promoter sites of the genes tested.

RESULTS

BMI-1 inhibition caused an increase in PHLPP1/2 expression and a decrease in phospho-AKT level in both cell lines. The glucose concentration and insulin stimulation differentially impact the AKT pathway through BMI-1 in cells differing in PTEN statuses. The expression of BMI-1 is dependent on the glucose concentration and insulin stimulation mostly in PTEN positive HEC-1A cells. In high glucose concentrations, BMI-1 affects AKT activity through PHLPPs and in hypoglycemia mostly through PTEN. BMI-1 inhibition impacts on genes involved in SNAIL, SLUG, and CDH1 and reduces endometrial cancer cells' migratory and invasive potential.

CONCLUSIONS

Our results indicate that the relationship between BMI-1 and phosphatases involved in AKT regulation depends on the glucose concentration and insulin stimulation.

Insulin-like growth factor system components expressed at the conceptus-maternal interface during the establishment of equine pregnancy

In many species, the insulin-like growth factors (IGF1 and IGF2), their receptors and IGF binding proteins play important roles in preparing the endometrium for implantation, and regulating conceptus growth and development. To determine whether the IGF system may contribute to conceptus-maternal interaction during equine pre-implantation development, we evaluated mRNA expression for IGF system components in conceptuses, and endometrium recovered from pregnant and cycling mares, on days 7, 14, 21 and 28 after ovulation. We also investigated expression of IGF1, IGF2 and their receptors 6 and 11 days after transfer of day 8 embryos to synchronous (day 8) or asynchronous (day 3) recipient mares. Expression of IGF1 and IGF2, IGF1R, IGF2R, INSR and IGFBPs 1, 2, 4 and 5 was evident in endometrium and conceptus membranes during days 7–28. Endometrial IGF2, INSR, IGFBP1 and IGFBP2 expression increased between days 7 and 28 of pregnancy. In conceptus membranes, expression of all IGF system components increased with developmental stage. Immunohistochemistry revealed strong expression of IGF1, IGF2 and IGF1R in both endometrium and conceptus membranes, whereas INSR was highly expressed in endometrium but barely detectable in the conceptus. Finally, a negatively asynchronous uterine environment retarded IGF1, IGF2 and INSR expression in the conceptus, whereas in the endometrium only INSR expression was altered by asynchrony. The presence of IGFs, their receptors and IGFBPs in the endometrium and conceptus during early equine pregnancy, and down-regulation in the conceptus following asynchronous embryo transfer, suggest a role in conceptus-maternal communication during the preparation for implantation.

Hyperinsulinemia induces early and dyssynchronous puberty in lean female mice

Girls with obesity are at increased risk of early puberty. Obesity is associated with insulin resistance and hyperinsulinemia. We hypothesized that insulin plays a physiological role in pubertal transition, and super-imposed hyperinsulinemia due to childhood obesity promotes early initiation of puberty in girls. To isolate the effect of hyperinsulinemia from adiposity, we compared pre-pubertal and pubertal states in hyperinsulinemic, lean muscle (M)-insulin-like growth factor 1 receptor (IGF-1R)-lysine (K)-arginine (R) (MKR) mice to normoinsulinemic WT, with puberty onset defined by vaginal opening (VO). Our results show MKR had greater insulin resistance and higher insulin levels (P < 0.05) than WT despite lower body weight (P < 0.0001) and similar IGF-1 levels (P = NS). Serum luteinizing hormone (LH) levels were higher in hyperinsulinemic MKR (P = 0.005), and insulin stimulation induced an increase in LH levels in WT. VO was earlier in hyperinsulinemic MKR vs WT (P < 0.0001). When compared on the day of VO, kisspeptin expression was higher in hyperinsulinemic MKR vs WT (P < 0.05), and gonadotropin-releasing hormone and insulin receptor isoform expression was similar (P = NS). Despite accelerated VO, MKR had delayed, disordered ovarian follicle and mammary gland development. In conclusion, we found that hyperinsulinemia alone without adiposity triggers earlier puberty. In our study, hyperinsulinemia also promoted dyssynchrony between pubertal initiation and progression, urging future studies in girls with obesity to assess alterations in transition to adulthood.

Intersections of endocrine pathways and the epithelial mesenchymal transition in endometrial cancer

The epithelial mesenchymal transition (EMT) is the process by which cancer cells of epithelial origin, including endometrial cancer, acquire a mesenchymal phenotype with enhanced migratory and invasive capacity, to facilitate metastasis. The regulation of EMT is tissue-specific, and in endometrial cancer, endocrine signaling pathways serve as critical regulators of EMT. The intersections of endocrine signaling and EMT highlight potential avenues for therapeutic intervention to target cancer metastasis with the aim of reduced mortality.

Cancers Detected During the Evaluation Before Bariatric Surgery in Obese Patients: a High-Risk Population for Cancers and Their Prevalence

PURPOSE

The purpose of the present study was to determine the types and prevalence of cancers in obese patients who have risks for cancer with multidisciplinary evaluation in managing the patients before bariatric surgery.

MATERIALS AND METHODS

The study had a descriptive cross-sectional method conducted by examining patients' files retrospectively. The frequency and types of diseases with cancer during the multidisciplinary evaluation of the study group with a BMI ≥ 40 kg/m2 before bariatric surgery were used as the study data.

RESULTS

A total of 1354 (64.97%) of these patients underwent bariatric surgery (for obesity), and 730 (35.02%) cases underwent metabolic surgery (type 2 diabetic patients). Eighteen patients had thyroid papillary cancer (0.86%) and colon cancer was detected in 8 people (0.38%), breast cancer in 6 people (0.47%), stomach cancer in 5 people (0.23%), kidney cancer in 3 people (0.1%) 4), lung cancer in 2 people (0.09%), pancreatic cancer in 2 people (0.09%), adrenal cancer in 2 people (0.09%), and neuroendocrine tumor in 1 person (0.04%).

CONCLUSION

It was found that obesity and some cancers are related. Weight loss to be achieved with obesity surgery can reduce the risk of obesity-related cancers.

Targeting obesity-related dysfunction in hormonally driven cancers

Obesity is a risk factor for at least 13 different types of cancer, many of which are hormonally driven, and is associated with increased cancer incidence and morbidity. Adult obesity rates are steadily increasing and a subsequent increase in cancer burden is anticipated. Obesity-related dysfunction can contribute to cancer pathogenesis and treatment resistance through various mechanisms, including those mediated by insulin, leptin, adipokine, and aromatase signalling pathways, particularly in women. Furthermore, adiposity-related changes can influence tumour vascularity and inflammation in the tumour microenvironment, which can support tumour development and growth. Trials investigating non-pharmacological approaches to target the mechanisms driving obesity-mediated cancer pathogenesis are emerging and are necessary to better appreciate the interplay between malignancy, adiposity, diet and exercise. Diet, exercise and bariatric surgery are potential strategies to reverse the cancer-promoting effects of obesity; trials of these interventions should be conducted in a scientifically rigorous manner with dose escalation and appropriate selection of tumour phenotypes and have cancer-related clinical and mechanistic endpoints. We are only beginning to understand the mechanisms by which obesity effects cell signalling and systemic factors that contribute to oncogenesis. As the rates of obesity and cancer increase, we must promote the development of non-pharmacological lifestyle trials for the treatment and prevention of malignancy.

Epidemiological link between obesity, type 2 diabetes mellitus and cancer

There exists a complex interaction between obesity, type 2 diabetes mellitus (T2DM) and cancer, and an increase in the incidence of cancer is expected with the growing obesity-diabetes pandemic. The association of cancer with diabetes mellitus and obesity appears to be site-specific, the highest risk being for post-menopausal breast cancer, endometrial cancer, and colorectal cancer. Moreover, there is worsening of hyperglycaemia with the onset of cancer, evidencing a bi-directional link between cancer and diabetes mellitus and the need for monitoring for diabetes in cancer survivors. In this review, we look at the epidemiological evidence from observational studies and Mendelian randomization studies linking obesity, diabetes, and cancer, as well as the complex pathophysiological mechanisms involved, including insulin resistance with associated hyperinsulinaemia, the effect of chronic low-grade inflammation, and the effect of various adipokines that are associated with obesity and T2DM. Additionally, we describe the novel therapeutic strategies, based on their role on the discrete pathophysiological mechanisms involved in the tumourigenesis.

Hyperinsulinemia in Obesity, Inflammation, and Cancer

The relative insufficiency of insulin secretion and/or insulin action causes diabetes. However, obesity and type 2 diabetes mellitus can be associated with an absolute increase in circulating insulin, a state known as hyperinsulinemia. Studies are beginning to elucidate the cause-effect relationships between hyperinsulinemia and numerous consequences of metabolic dysfunctions. Here, we review recent evidence demonstrating that hyperinsulinemia may play a role in inflammation, aging and development of cancers. In this review, we will focus on the consequences and mechanisms of excess insulin production and action, placing recent findings that have challenged dogma in the context of the existing body of literature. Where relevant, we elaborate on the role of specific signal transduction components in the actions of insulin and consequences of chronic hyperinsulinemia. By discussing the involvement of hyperinsulinemia in various metabolic and other chronic diseases, we may identify more effective therapeutics or lifestyle interventions for preventing or treating obesity, diabetes and cancer. We also seek to identify pertinent questions that are ripe for future investigation.

Chlorpromazine Sensitizes Progestin-Resistant Endometrial Cancer Cells to MPA by Upregulating PRB

Medroxyprogesterone acetate (MPA) is the main conservative treatment for endometrial cancer (EC) patients desirable to preserve fertility and those who cannot suffer from surgery. Considering the high incidence of progestin resistance and recurrence of MPA treatment, we reproposed antipsychotics chlorpromazine (CPZ) as a new strategy for both progestin-sensitive and -resistant endometrial cancer. Cytobiology experiments indicated that CPZ could significantly suppress proliferation, migration/invasion and induce apoptosis in Ishikawa (ISK) and KLE EC cell lines. And xenograft mouse models were constructed to validate the antitumor effect and toxicity of CPZ in-vivo. CPZ inhibited the growth at a low dose of 3mg/kg and the mice exhibited no signs of toxicity. Next, concomitant treatment and sequential treatment with CPZ and MPA were proceeded to analysis the synergistic effect in EC cells. Concomitant treatment only performed a limited synergistic effect on apoptosis in ISK and KLE cells. Nevertheless, sequential treatment showed favorable synergistic effects in progestin-resistant KLE cells. Finally, a stable MPA-resistant cell line shRNA was established to explore the mechanism of CPZ reversing progestin resistance. Immunoblot data showed that CPZ inhibited the activation of PI3K/AKT signal in ISK and KLE cells and upregulated PRB expression in progestin-resistant cells, by which CPZ overcame progestin resistance to MPA. Thus, CPZ might act as a candidate drug for conservative treatment and sequential treatment with CPZ and MPA could be a suitable therapeutic option for progestin resistant patients.

Endometrial biomarkers in premenopausal women with obesity: an at-risk cohort

BACKGROUND

Obesity is a well-known risk factor for endometrial cancer, but the mechanisms of obesity-related carcinogenesis are not well defined, particularly for premenopausal women. With the continuing obesity epidemic, increases in the incidence of endometrial cancer and a younger age of diagnosis are often attributed to a hyperestrogenic state created by hormone production in adipose tissue, but significant knowledge gaps remain. The balance of estrogen-responsive signals has not been defined in the endometrium of premenopausal women with obesity, where obesity may not create hyperestrogenism in the context of ovaries being the primary source of estrogen production. Obesity is associated with a state of low-grade, chronic inflammation that can promote tumorigenesis, and it is also known that hormonal changes alter the immune microenvironment of the endometrium. However, limited research has been conducted on endometrial immune-response changes in women who have an increased risk for cancer due to obesity.

OBJECTIVE

Endometrial estrogen-regulated biomarkers, previously shown to be dysregulated in endometrial cancer, were evaluated in a cohort of premenopausal women to determine if obesity is associated with differences in the biomarker expression levels, which might reflect an altered risk of developing cancer. The expression of a multiplexed panel of immune-related genes was also evaluated for expression differences related to obesity.

STUDY DESIGN

Premenopausal women with a body mass index of ≥30 kg/m² (n=97) or a body mass index of ≤25 kg/m² (n=33) were prospectively enrolled in this cross-sectional study, which included the assessment of serum metabolic markers and a timed endometrial biopsy for pathologic evaluation, hormone-regulated biomarker analysis, and immune response gene expression analysis. Medical and gynecologic histories were obtained. Endometrial gene expression markers were also compared across the body mass index groups in a previous cohort of premenopausal women with an inherited cancer risk (Lynch syndrome).

RESULTS

In addition to known systemic metabolic differences, histologically normal endometria from women with obesity showed a decrease in gene expression of progesterone receptor (P=.0027) and the estrogen-induced genes retinaldehyde dehydrogenase 2 (P=.008), insulin-like growth factor 1 (P=.016), and survivin (P=.042) when compared with women without obesity. The endometrial biomarkers insulin-like growth factor 1, survivin, and progesterone receptor remained statistically significant in multivariate linear regression models. In contrast, women with obesity and Lynch syndrome had an increased expression of insulin-like growth factor 1 (P=.017). There were no differences in endometrial proliferation, and limited endometrial immune differences were observed.

CONCLUSION

When comparing premenopausal women with and without obesity in the absence of endometrial pathology or an inherited cancer risk, the expression of the endometrial biomarkers does not reflect a local hyperestrogenic environment, but it instead reflects a decreased cancer risk profile that may be indicative of a compensated state. In describing premenopausal endometrial cancer risk, it may be insufficient to attribute a high-risk state to obesity alone; further studies are warranted to evaluate individualized biomarker profiles for differences in the hormone-responsive signals or immune response. In patients with Lynch syndrome, the endometrial biomarker profile suggests that obesity further increases the risk of developing cancer.

Immunohistochemical expression of insulin-like growth factor-1Ec in primary endometrial carcinoma: Association with PTEN, p53 and survivin expression

Chronic hyperinsulinemia due to insulin resistance and elevated levels of insulin-like growth factor (IGF)-1 and IGF-2 are suggestive of a significantly higher risk of endometrial carcinoma. There is a wealth of evidence showing differential expression of IGF-1 isoforms in various types of cancer. In the present study, 99 archived endometrial carcinoma tissue sections were retrospectively assessed by immunohistochemistry for IGF-1Ec isoform expression. Expression of IGF-1Ec was also assessed in nine cases of non-neoplastic endometrial tissue adjacent to the tumor, in 30 cases with normal endometrium and in 30 cases with endometrial hyperplasia. Furthermore, the association between IGF-1Ec and the concurrent expression of phosphatase and tensin homologue deleted on chromosome 10 (PTEN), p53 or survivin was assessed, as well as their combined expression in association with clinicopathological variables. In endometrial carcinoma, IGF-1Ec expression was high in non-endometrioid carcinoma (serous papillary or clear cell carcinoma) compared with that in endometrioid adenocarcinoma. IGF-1Ec expression was also high in the presence of tumoral necrosis. Furthermore, there was a significant correlation between the histological differentiation and the sum of staining intensity and the number of IGF-1Ec immunopositive cells in endometrial carcinoma. There was a moderate negative correlation between co-expression of IGF-1Ec and PTEN, for both the number of immunopositive cells (P=0.006, ρ=−0.343) and the sum of staining (scores and intensity; P=0.006, ρ=−0.343). Furthermore, there was a positive correlation between the sum of staining (scores and intensity) and co-expression of IGF-1Ec and survivin (P=0.043, ρ=0.225). However, there was no association between concomitant expression of IGF-1Ec and p53. These results emphasized the importance of IGF-1Ec expression during development of non-estrogen dependent endometrial adenocarcinoma. IGF-1Ec and PTEN may function opposingly during endometrial carcinogenesis. By contrast, IGF-1Ec and survivin may share common molecular pathways and may promote, in parallel, tumoral development.

Insulin Resistance and Endometrial Cancer: Emerging Role for microRNA

Endometrial cancer (EC) remains one of the most common cancers of the female reproductive system. Epidemiological and clinical data implicate insulin resistance (IR) and its accompanying hyperinsulinemia as key factors in the development of EC. MicroRNAs (miRNAs) are short molecules of non-coding endogenous RNA that function as post-transcriptional regulators. Accumulating evidence has shown that the miRNA expression pattern is also likely to be associated with EC risk factors. The aim of this work was the verification of the relationships between IR, EC, and miRNA, and, as based on the literature data, elucidation of miRNA's potential utility for EC prevention in IR patients. The pathways affected in IR relate to the insulin receptors, insulin-like growth factors and their receptors, insulin-like growth factor binding proteins, sex hormone-binding globulin, and estrogens. Herein, we present and discuss arguments for miRNAs as a plausible molecular link between IR and EC development. Specifically, our careful literature search indicated that dysregulation of at least 13 miRNAs has been ascribed to both conditions. We conclude that there is a reasonable possibility for miRNAs to become a predictive factor of future EC in IR patients.

Baseline Endometrial Thickness or Endometrial Thickness Change in Response to Estrogen Is Not Predictive of Frozen Embryo Transfer Success in Medicated Cycles

There is some consensus that endometrial thickness (EMT) needs to be at least 7 mm on day of embryo transfer. However, the predictive role of baseline EMT and EMT change in response to estrogen is largely unknown. The objective of this study was to evaluate the role of endometrial thickness in frozen embryo transfer (FET) cycles. We analyzed the association of baseline endometrial thickness (EMTb-Day 3 of cycle) and endometrial thickness change (EMTΔ-from baseline to start of progesterone supplementation) with FET success in 121 cycles. We also investigated whether baseline estradiol levels and body mass index (BMI) are associated with EMTb. No difference was observed in EMTb and EMTΔ in cycles resulting in clinical pregnancy compared to unsuccessful transfers (5.1 ± 2.2 mm vs 5.0 ± 1.9 mm; p = 0.92, and 4.7 ± 2.4 mm vs. 4.4 ± 2.4 mm; p = 0.56). When 7 mm cut-off was used, endometrial thickness on the day of start of progesterone supplementation (EMTp) was also not different between groups (9.8 ± 2.9 mm vs. 9.4 ± 2.5 mm; p = 0.50). Multivariable logistic regression models did not demonstrate any predictive value of EMTb, EMTp, or EMTΔ in predicting success of FET cycles (p = 0.92, p = 0.80, and p = 0.84, respectively). There was no significant correlation between EMTb and baseline estradiol levels (r = -0.001; p = 0.985). BMI showed statistically significant weak positive linear relationship with EMTb (r = +0.29; p = 0.002). Our study did not demonstrate any significant relationship between baseline endometrial thickness or endometrial thickness change and clinical pregnancy rates in frozen embryo transfer cycles. Significant positive linear relationship of BMI with baseline endometrial thickness, despite no correlation between baseline estradiol and EMTb, points to the role of possible other mechanism affecting EMT besides estradiol in obese patients.

Insulin Signaling Via Progesterone-Regulated Insulin Receptor Substrate 2 is Critical for Human Uterine Decidualization

Decidualization, the process by which fibroblastic human endometrial stromal cells (HESC) differentiate into secretory decidual cells, is a critical event during the establishment of pregnancy. It is dependent on the steroid hormone progesterone acting through the nuclear progesterone receptor (PR). Previously, we identified insulin receptor substrate 2 (IRS2) as a factor that is directly regulated by PR during decidualization. IRS2 is an adaptor protein that functionally links receptor tyrosine kinases, such as insulin receptor (IR) and insulin-like growth factor 1 receptor (IGF1R), and their downstream effectors. IRS2 expression was induced in HESC during in vitro decidualization and siRNA-mediated downregulation of IRS2 transcripts resulted in attenuation of this process. Further use of siRNAs targeted to IR or IGF1R transcripts showed that downregulation of IR, but not IGF1R, led to impaired decidualization. Loss of IRS2 transcripts in HESC suppressed phosphorylation of both ERK1/2 and AKT, downstream effectors of insulin signaling, which mediate gene expression associated with decidualization and regulate glucose uptake. Indeed, downregulation of IRS2 resulted in reduced expression and membrane localization of the glucose transporters GLUT1 and GLUT4, resulting in lowered glucose uptake during stromal decidualization. Collectively, these data suggest that the PR-regulated expression of IRS2 is necessary for proper insulin signaling for controlling gene expression and glucose utilization, which critically support the decidualization process to facilitate pregnancy. This study provides new insight into the mechanisms by which steroid hormone signaling intersects with insulin signaling in the uterus during decidualization, which has important implications for pregnancy complications associated with insulin resistance and infertility.

Decreased NDRG1 expression is associated with pregnancy loss in mice and attenuates the in vitro decidualization of endometrial stromal cells

Embryo implantation is an essential step for a successful pregnancy, and any defect in this process can lead to a range of pregnancy pathologies. The objective of this study was to explore the role of N-myc downregulated gene 1 (NDRG1) in embryo implantation. It was found that uterine NDRG1 expression has a dynamic pattern during the estrous cycle in nonpregnant mice and that uterine NDRG1 expression was elevated during the implantation process in pregnant mice. The distinct accumulation of NDRG1 protein signals was observed in the primary decidual zone adjacent to the implanting embryo during early pregnancy. Furthermore, uterine NDRG1 expression could be induced by activated implantation or artificial decidualization in mice. Decreased uterine NDRG1 expression was associated with pregnancy loss in mice and was associated with recurrent miscarriages in humans. The in vitro decidualization of both mouse and human endometrial stromal cells (ESCs) was accompanied by increased NDRG1 expression and downregulated NDRG1 expression in ESCs effectively inhibited decidualization. Collectively, these data suggest that NDRG1 plays an important role in decidualization during the implantation process, and the abnormal expression of NDRG1 may be involved in pregnancy loss.

Glycogen metabolism in mink uterine epithelial cells and its regulation by estradiol, progesterone and insulin

Glycogen content in mink uterine glandular and luminal epithelia (GE and LE) is maximal during estrus and is depleted before implantation while embryos are in diapause. Uterine glycogen synthesis in vivo is stimulated by estradiol (E₂) while its mobilization is induced by progesterone (P₄). Nevertheless, treatment of an immortalized mink uterine epithelial cell line (GMMe) with E₂ did not affect glycogen production. Interestingly, insulin alone significantly increased synthesis of the nutrient and glycogen content in response to insulin + E₂ was greater than for insulin alone. Our objectives were to determine: 1) If insulin receptor protein (INSR) is expressed by mink uterine GE and LE in vivo and if the amount differs between estrus, diapause and pregnancy; 2) if E₂, P₄ or insulin regulate insulin receptor gene (Insr) expression by GMMe cells, and 3) if E₂ and P₄ act independently to regulate glycogen metabolism by GMMe cells and/or if their effects are mediated in part through the actions of insulin. The mean (±S.E.) percent INSR content of uterine epithelia was greatest during diapause (GE: 15.65 ± 0.06, LE:16.56 ± 1.25), much less during pregnancy (GE: 2.53 ± 0.60, LE:2.25 ± 0.32) and barely detectable in estrus (GE: 0.03 ± 0.01, LE:0.02 ± 0.01). Glycogen concentrations in GMMe cells increased 10-fold in response to insulin and 20-fold with insulin + E₂ when compared to controls. Expression of Insr was increased 2-fold by insulin and insulin + E₂ when compared to controls and there was no difference between the two hormone treatments, indicating that E₂ does not increase Insr expression in insulin-treated cells. To simulate E₂-priming, cells were treated with Insulin + E₂ for 24 h, followed by the same hormones + P₄ for the second 24 h (Insulin + E₂ → P₄) which resulted in Insr and glycogen levels not different from controls. Similarly, cells treated with Insulin + P₄ resulted in glycogen concentrations not different from controls. We conclude that the glycogenic actions of E₂ on GMMe cells are due to increased responsiveness of the cells to insulin, but not as a result of up-regulation of the insulin receptor. Glycogen mobilization in response to P₄ was the result of decreased glycogenesis and increased glycogenolysis occurring concomitantly with reduced Insr expression. Mink uterine glycogen metabolism appears to be regulated in a reproductive cycle-dependent manner in part as a result of the actions of E₂ and P₄ on cellular responsiveness to insulin.

MicroRNA-320a acts as a tumor suppressor in endometrial carcinoma by targeting IGF-1R

Dysregulation of microRNAs (miRs) is implicated in the carcinogenesis of various types of malignant tumor by manipulating cell growth and apoptosis. Abnormal expression of miR‑320a is involved in tumorigenesis of many types of cancer. The potential association of miR‑320a and the possible regulatory mechanisms in endometrial carcinoma is rarely elucidated. In the present study, it was demonstrated that miR‑320a expression was decreased in endometrial carcinoma tissues and cell lines. The present results also indicated that overexpression of miR‑320a suppressed cell proliferation through inducing G2/M phrase arrest and apoptosis. Insulin‑like growth factor receptror‑1 (IGF‑1R) was verified to be the potential target of miR‑320a by computational analysis and luciferase reporter assays. In addition, overexpression of miR‑320a reduced endogenous IGF‑1R expression in cells. Furthermore, it was demonstrated that upregulation of miR‑320a inhibited phosphorylated (p)‑protein kinase B and p‑mechanistic target of rapamycin activation and promoted B cell lymphoma‑2‑associated death promoter expression. Reintroduction of IGF‑1R into miR‑320a‑overexpressed cells antagonized the impact of miR‑320a on its downstream protein, which demonstrated that the tumor suppressive role of miR‑320a in endometrial carcinoma is exerted by the signal pathway mediated by IGF‑1R. It was therefore concluded that miR‑320a served an anti‑tumor role on endometrial carcinoma through the regulation of IGF‑1R, and miR‑320a may be used as the target for the gene therapy of endometrial carcinoma.

Insulin Receptor Isoforms in Cancer

The insulin receptor (IR) mediates both metabolic and mitogenic effects especially when overexpressed or in clinical conditions with compensatory hyperinsulinemia, due to the metabolic pathway resistance, as obesity diabetes. In many cancers, IR is overexpressed preferentially as IR-A isoform, derived by alternative splicing of exon 11. The IR-A overexpression, and the increased IR-A:IR-B ratio, are mechanisms that promote the mitogenic response of cancer cells to insulin and IGF-2, which is produced locally by both epithelial and stromal cancer cells. In cancer IR-A, isoform predominance may occur for dysregulation at both mRNA transcription and post-transcription levels, including splicing factors, non-coding RNAs and protein degradation. The mechanisms that regulate IR isoform expression are complex and not fully understood. The IR isoform overexpression may play a role in cancer cell stemness, in tumor progression and in resistance to target therapies. From a clinical point of view, the IR-A overexpression in cancer may be a determinant factor for the resistance to IGF-1R target therapies for this issue. IR isoform expression in cancers may have the meaning of a predictive biomarker and co-targeting IGF-1R and IR-A may represent a new more efficacious treatment strategy.

IR-A/IGF-1R-mediated signals promote epithelial-mesenchymal transition of endometrial carcinoma cells by activating PI3K/AKT and ERK pathways

BACKGROUND

Obesity is a risk factor for endometrial cancer (EC). However, it is not known how insulin receptor isoform A (IR-A) and insulin-like growth factor 1 receptor (IGF-1R), cognate receptors for insulin and IGFs, respectively, regulate malignant behaviors of EC. In this study, we examined the biological effects of IR-A/IGF-1R, explored the downstream signaling cascades, and assessed the therapeutic potential of targeting IR-A/IGF-1R in vivo.

METHODS

The expression levels of IR-A and IGF-1R were examined by qRT-PCR and Western blotting. Upon down-regulating IR-A and/or IGF-1R by sh-IR-A and/or sh-IGF-1R, respectively, cell migration, invasion, apoptosis, and epithelial-mesenchymal transition (EMT) were examined by wound healing, transwell invasion, flow cytometry, and Western blotting, respectively. Furthermore, the effect of sh-IR-A and/or sh-IGF-1R on phosphatidylinositide 3-kinases (PI3K)/AKT and ERK pathways was measured by Western blotting. Lastly, we monitored xenograft growth and EMT in vivo.

RESULTS

Both IR-A and IGF-1R were significantly up-regulated in EC cells. Knockdown of IR-A or IGF-1R alone was sufficient to reduce migration and invasion, enhance apoptosis, and inhibit EMT of EC cells, and the most significant alterations were observed in cells co-transfected with sh-IR-A+ sh-IGF-1R. These phenotypes were associated with inactivating PI3K/AKT and ERK signaling by sh-IR-A and/or sh-IGF-1R. Consistent with in vitro findings, sh-IR-A or sh-IGF-1R significantly inhibited xenograft growth and EMT in vivo.

CONCLUSION

IR-A and IGF-1R-mediated signals, by activating PI3K/AKT and ERK pathways, can induce multiple malignant phenotypes of EC cells. Therefore, targeting IR-A or IGF-1R may provide therapeutic benefits for EC.

Insulin Regulates Glycogen Synthesis in Human Endometrial Glands Through Increased GYS2

CONTEXT

Glycogen synthesis is a critical metabolic function of the endometrium to prepare for successful implantation and sustain embryo development. Yet, regulation of endometrial carbohydrate metabolism is poorly characterized. Whereas glycogen synthesis is attributed to progesterone, we previously found that the metabolic B isoform of the insulin receptor is maximally expressed in secretory-phase endometrium, indicating a potential role of insulin in glucose metabolism.

OBJECTIVE

We sought to determine whether insulin or progesterone regulates glycogen synthesis in human endometrium.

DESIGN, PARTICIPANTS, OUTCOME MEASUREMENTS

Endometrial epithelial cells were isolated from 28 healthy women and treated with insulin, medroxyprogesterone (MPA), or vehicle. Intracellular glycogen and the activation of key enzymes were quantified.

RESULTS

In epithelia, insulin induced a 4.4-fold increase in glycogen, whereas MPA did not alter glycogen content. Insulin inactivated glycogen synthase (GS) kinase 3α/β (GSK3α/β), relieving inhibition of GS. In a regulatory mechanism, distinct from liver and muscle, insulin also increased GS by 3.7-fold through increased GS 2 (GYS2) gene expression.

CONCLUSIONS

We demonstrate that insulin, not progesterone, directly regulates glycogen synthesis through canonical acute inactivation of GSK3α/β and noncanonical stimulation of GYS2 transcription. Persistently elevated GS enables endometrium to synthesize glycogen constitutively, independent of short-term nutrient flux, during implantation and early pregnancy. This suggests that insulin plays a key, physiological role in endometrial glucose metabolism and underlines the need to delineate the effect of maternal obesity and hyperinsulinemia on fertility and fetal development.

The Relation of Obesity-Related Hormonal and Cytokine Levels With Multiple Myeloma and Non-Hodgkin Lymphoma

This article presents the first detailed overview of the mechanisms that may underlie the relation of obesity with B-cell non-Hodgkin lymphomas (NHLs) and multiple myeloma (MM). Epidemiologic studies, including meta-analyses of prospective cohorts, have reported that the risks of NHL and MM are significantly increased in obese, relative to normal weight, women and men. Accumulating experimental and clinical evidence suggests that inflammatory cytokines, hyperinsulinemia, and sex hormones could play a role in the association of obesity with B-cell NHL and MM carcinogenesis. There is, however, a paucity of data published from appropriate large prospective cohort studies, and studies concurrently measuring these correlated factors, to formally determine the likely biologic factors driving the relationship of obesity with NHL and MM. Additional strengths and weaknesses of the current literature, as well as study design issues that need to be considered in conducting these studies, such as the exclusion of type 2 diabetics or postmenopausal women using hormone therapy, are discussed.

Insulin Receptor Isoforms in Physiology and Disease: An Updated View

The insulin receptor (IR) gene undergoes differential splicing that generates two IR isoforms, IR-A and IR-B. The physiological roles of IR isoforms are incompletely understood and appear to be determined by their different binding affinities for insulin-like growth factors (IGFs), particularly for IGF-2. Predominant roles of IR-A in prenatal growth and development and of IR-B in metabolic regulation are well established. However, emerging evidence indicates that the differential expression of IR isoforms may also help explain the diversification of insulin and IGF signaling and actions in various organs and tissues by involving not only different ligand-binding affinities but also different membrane partitioning and trafficking and possibly different abilities to interact with a variety of molecular partners. Of note, dysregulation of the IR-A/IR-B ratio is associated with insulin resistance, aging, and increased proliferative activity of normal and neoplastic tissues and appears to sustain detrimental effects. This review discusses novel information that has generated remarkable progress in our understanding of the physiology of IR isoforms and their role in disease. We also focus on novel IR ligands and modulators that should now be considered as an important strategy for better and safer treatment of diabetes and cancer and possibly other IR-related diseases.

Effect of Preconception Impaired Glucose Tolerance on Pregnancy Outcomes in Women With Polycystic Ovary Syndrome

CONTEXT

Women with polycystic ovary syndrome (PCOS) commonly have intrinsic insulin resistance and are recommended to undergo an oral glucose tolerance test (OGTT) for diabetes screening. However, the effect of preconception impaired glucose tolerance (IGT) on pregnancy is still unclear.

OBJECTIVE

To prospectively assess the effect of preconception IGT on pregnancy outcomes.

DESIGN, SETTING, PATIENTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES

This was a secondary analysis of a multicenter randomized trial in 1508 women with PCOS comparing live birth and obstetric complications between fresh and frozen embryo transfer. At baseline, fasting and 2-hour glucose and insulin levels after 75-g OGTT were measured.

RESULTS

Women with preconception IGT had higher risks of gestational diabetes in both singleton pregnancy [9.5% vs 3.2%; odds ratio (OR) 3.13; 95% confidence interval (CI) 1.23to 7.69] and twin pregnancy (20.0% vs 3.2%; OR 7.69; 95% CI 2.78 to 20.00) than women with normoglycemia. Preconception IGT was associated with a higher risk of large for gestational age in singleton newborns compared with normoglycemia (34.7% vs 19.8%; OR 2.13; 95% CI 1.19 to 3.85) or isolated impaired fasting glucose (i-IFG) (34.7% vs 15.4%; OR 2.94; 95% CI 1.33 to 6.25). Women with preconception IGT had a higher singleton pregnancy loss rate than women with i-IFG (31.4% vs 17.5%; OR 2.17; 95% CI 1.11 to 4.17). After adjusting for age, body mass index, duration of infertility, total testosterone level, and treatment groups (frozen vs fresh embryo transfer), these associations remained.

CONCLUSIONS

Preconception IGT, independent from BMI, was associated with adverse pregnancy outcome compared with i-IFG and normoglycemia.

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.