GLUT-1 is preferentially expressed in atypical endometrial hyperplasia and endometrial adenocarcinoma

On the Role of Glycolysis in Early Tumorigenesis-Permissive and Executioner Effects

Reprogramming energy production from mitochondrial respiration to glycolysis is now considered a hallmark of cancer. When tumors grow beyond a certain size they give rise to changes in their microenvironment (e.g., hypoxia, mechanical stress) that are conducive to the upregulation of glycolysis. Over the years, however, it has become clear that glycolysis can also associate with the earliest steps of tumorigenesis. Thus, many of the oncoproteins most commonly involved in tumor initiation and progression upregulate glycolysis. Moreover, in recent years, considerable evidence has been reported suggesting that upregulated glycolysis itself, through its enzymes and/or metabolites, may play a causative role in tumorigenesis, either by acting itself as an oncogenic stimulus or by facilitating the appearance of oncogenic mutations. In fact, several changes induced by upregulated glycolysis have been shown to be involved in tumor initiation and early tumorigenesis: glycolysis-induced chromatin remodeling, inhibition of premature senescence and induction of proliferation, effects on DNA repair, O-linked N-acetylglucosamine modification of target proteins, antiapoptotic effects, induction of epithelial-mesenchymal transition or autophagy, and induction of angiogenesis. In this article we summarize the evidence that upregulated glycolysis is involved in tumor initiation and, in the following, we propose a mechanistic model aimed at explaining how upregulated glycolysis may play such a role.

Metabolic reprogramming and interventions in endometrial carcinoma

Cancer cells are usually featured by metabolic adaptations that facilitate their growth, invasion, and metastasis. Thus, reprogramming of intracellular energy metabolism is currently one of the hotspots in the field of cancer research. Whereas aerobic glycolysis (known as the Warburg effect) has long been considered a dominant form of energy metabolism in cancer cells, emerging evidence indicates that other metabolic forms, especially oxidative phosphorylation (OXPHOS), may play a critical role at least in some types of cancer. Of note, women with metabolic syndromes (MetS), including obesity, hyperglycemia, dyslipidemia, and hypertension, have an increased risk of developing endometrial carcinoma (EC), suggesting a close link between metabolism and EC. Interestingly, the metabolic preferences vary among EC cell types, particularly cancer stem cells and chemotherapy-resistant cells. Currently, it is commonly accepted that glycolysis is the main energy provider in EC cells, while OXPHOS is reduced or impaired. Moreover, agents specifically targeting the glycolysis and/or OXPHOS pathways can inhibit tumor cell growth and promote chemosensitization. For example, metformin and weight control not only reduce the incidence of EC but also improve the prognosis of EC patients. In this review, we comprehensively overview the current in-depth understanding of the relationship between metabolism and EC and provide up-to-date insights into the development of novel therapies targeting energy metabolism for auxiliary treatment in combination with chemotherapy for EC, especially those resistant to conventional chemotherapy.

Glucose metabolic reprogramming and its therapeutic potential in obesity-associated endometrial cancer

Endometrial cancer (EC) is a common gynecological cancer that endangers women health. Although substantial progresses of EC management have been achieved in recent years, the incidence of EC still remains high. Obesity has been a common phenomenon worldwide that increases the risk of EC. However, the mechanism associating obesity and EC has not been fully understood. Metabolic reprogramming as a remarkable characteristic of EC is currently emerging. As the primary factor of metabolic syndrome, obesity promotes insulin resistance, hyperinsulinemia and hyperglycaemia. This metabolic disorder remodels systemic status, which increases EC risk and is related with poor prognosis. Glucose metabolism in EC cells is complex and mediated by glycolysis and mitochondria to ensure energy requirement. Factors that affect glucose metabolism may have an impact on EC initiation and progression. In this study, we review the glucose metabolic reprogramming of EC not only systemic metabolism but also inherent tumor cell metabolism. In particular, the role of glucose metabolic regulation in malignant properties of EC will be focused. Understanding of metabolic profile and glucose metabolism-associated regulation mechanism in EC may provide novel perspective for treatment.

Glucose transporters: Important regulators of endometrial cancer therapy sensitivity

Glucose is of great importance in cancer cellular metabolism. Working together with several glucose transporters (GLUTs), it provides enough energy for biological growth. The main glucose transporters in endometrial cancer (EC) are Class 1 (GLUTs 1–4) and Class 3 (GLUTs 6 and 8), and the overexpression of these GLUTs has been observed. Apart from providing abundant glucose uptake, these highly expressed GLUTs also participate in the activation of many crucial signaling pathways concerning the proliferation, angiogenesis, and metastasis of EC. In addition, overexpressed GLUTs may also cause endometrial cancer cells (ECCs) to be insensitive to hormone therapy or even resistant to radiotherapy and chemoradiotherapy. Therefore, GLUT inhibitors may hopefully become a sensitizer for EC precision-targeted therapies. This review aims to summarize the expression regulation, function, and therapy sensitivity of GLUTs in ECCs, aiming to provide a new clue for better diagnosis and treatment of EC.

SUOX and GLUT1 are biomarkers for the prognosis in large duct type intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) is the second most common hepatic malignant disease and has a poor prognosis, but few biomarkers have been found. SUOX is an important factor in energy metabolism and a poor prognostic factor in other malignancies. In this study, we aimed to clarify the relationship between SUOX and GLUT expression in large duct type iCCA and the mechanism of mitochondrial energy metabolism in iCCA. We evaluated SUOX and GLUT1 expression in 96 large duct type iCCA cases and proportion score (PS) was used to evaluate the expression; receiver operating characteristic (ROC) curves of both SUOX and GLUT1 expression were generated, and the Kaplan-Meier method and Cox regression analysis were used to estimate overall survival. Of the 96 iCCA cases, 73 (76.0%) showed low SUOX expression and 66 (68.8%) showed high GLUT1 expression. The 5-year survival rate of iCCA with low SUOX expression was significantly shorter than that of iCCA with high SUOX expression (p = 0.001). In contrast, the 5-year survival rate of iCCA with high GLUT1 expression was significantly shorter than that of iCCA with low GLUT1 expression (p = 0.005). According to Spearman's correlation, there was no correlation between SUOX and GLUT1. Conversely, the combination of low SUOX and high GLUT1 expression was the most common in 51 of 96 cases (53.1%), and the overall survival was significantly shorter than that of patients with other combinations. Furthermore, SUOX was shown to be an independent prognostic factor together with GLUT1, suggesting that SUOX in combination with GLUT1 can predict the prognosis of large duct type iCCA.

Hyperandrogenic Milieu Dysregulates the Expression of Insulin Signaling Factors and Glucose Transporters in the Endometrium of Patients With Polycystic Ovary Syndrome

PURPOSE

Subfertility associated with polycystic ovary syndrome (PCOS) mainly originates from oligoovulation/anovulation. Although insulin resistance and androgen excess are known to cause PCOS-associated implantation failure, the consequences of PCOS on endometrial homeostasis and pathophysiology have not been comprehensively understood. In this study, we examined whether the pathophysiologic milieu of PCOS intrinsically affects expression profiles of genes related to insulin signaling and facilitative glucose transporters (GLUTs) in the human endometrium and/or during in vitro decidualization.

STUDY DESIGN

Seven healthy women with regular menstrual cycles and 13 patients with PCOS were recruited for this study. To mimic the hyperandrogenic or hyperinsulinemic milieu in the endometrium of patient with PCOS (PCOSE) in vitro, human endometrial stromal cells (hESCs) were treated with dihydrotestosterone (DHT) or insulin, respectively.

RESULTS

In PCOSE, messenger RNA (mRNA) levels of insulin receptor (IR), IR substrate (IRS) 1, and IRS2 were significantly increased. Furthermore, GLUT1 and GLUT12 were aberrantly increased. Chronic exposure to insulin or DHT aberrantly increased IRS1/IRS2 phosphorylation and protein levels of GLUT1 and GLUT12 in hESCs, suggesting that not only hyperinsulinemic but also hyperandrogenic conditions affect insulin signaling and glucose metabolism. The mRNA microarrays demonstrated that DHT dysregulates various gene sets, including cell cycle and glucose metabolism, in hESCs. Furthermore, DHT suppressed the expression of GLUT1 and GLUT12 as well as decidualization markers, IGFBP1 and prolactin, during in vitro decidualization.

CONCLUSIONS

The hyperandrogenic milieu affects gene expression profiles, including gene sets associated with insulin signaling, cell cycle, glucose metabolism, and/or glucose transport, in human endometrium and during in vitro decidualization.

Hyperandrogenic Milieu Dysregulates the Expression of Insulin Signaling Factors and Glucose Transporters in the Endometrium of Patients With Polycystic Ovary Syndrome

PURPOSE:

Subfertility associated with polycystic ovary syndrome (PCOS) mainly originates from oligoovulation/anovulation. Although insulin resistance and androgen excess are known to cause PCOS-associated implantation failure, the consequences of PCOS on endometrial homeostasis and pathophysiology have not been comprehensively understood. In this study, we examined whether the pathophysiologic milieu of PCOS intrinsically affects expression profiles of genes related to insulin signaling and facilitative glucose transporters (GLUTs) in the human endometrium and/or during in vitro decidualization.

STUDY DESIGN:

Seven healthy women with regular menstrual cycles and 13 patients with PCOS were recruited for this study. To mimic the hyperandrogenic or hyperinsulinemic milieu in the endometrium of patient with PCOS (PCOSE) in vitro, human endometrial stromal cells (hESCs) were treated with dihydrotestosterone (DHT) or insulin, respectively.

RESULTS:

In PCOSE, messenger RNA (mRNA) levels of insulin receptor (IR), IR substrate (IRS) 1, and IRS2 were significantly increased. Furthermore, GLUT1 and GLUT12 were aberrantly increased. Chronic exposure to insulin or DHT aberrantly increased IRS1/IRS2 phosphorylation and protein levels of GLUT1 and GLUT12 in hESCs, suggesting that not only hyperinsulinemic but also hyperandrogenic conditions affect insulin signaling and glucose metabolism. The mRNA microarrays demonstrated that DHT dysregulates various gene sets, including cell cycle and glucose metabolism, in hESCs. Furthermore, DHT suppressed the expression of GLUT1 and GLUT12 as well as decidualization markers, IGFBP1 and prolactin, during in vitro decidualization.

CONCLUSIONS:

The hyperandrogenic milieu affects gene expression profiles, including gene sets associated with insulin signaling, cell cycle, glucose metabolism, and/or glucose transport, in human endometrium and during in vitro decidualization.

Expression of Glut-1 in Normal Endometrium and Endometrial Lesions: Analysis of 336 Cases

Background: Glucose transporter-1 (Glut-1) is a membrane glycoprotein that is, together with other glucose transporters, responsible for the regulation of glucose uptake. An increased expression of this protein seems to be a general feature of several malignant tumors that are able to reprogram their metabolism and switch from oxidative phosphorylation to aerobic glycolysis. Methods: We performed comprehensive immunohistochemical analysis of Glut-1 expression in 336 endometrial samples, including tumors, nontumor lesions, and normal tissues. Results: Expression of Glut-1 was found in 87% of endometrioid carcinomas (160/184 cases), 100% of serous carcinomas (29/29 cases), 100% of clear cell carcinomas (17/17 cases), 50% of polyps with atypical hyperplasia (8/16 cases), 12.5% of polyps with non-atypical hyperplasia (3/24 cases), 77% of hyperplasias with atypias (10/13 cases), 9% of hyperplasias without atypias (1/11 cases), 87% of secretory endometrium samples (13/15 cases), and in none of the nonsecretory endometrium samples (0/27 cases). In endometrioid carcinomas, Glut-1 was expressed in a marked geographical pattern. In nontumor lesions, its expression was more common in atypical hyperplasia and polyps with atypical hyperplasia compared with polyps with non-atypical hyperplasia and hyperplasias without atypia ( P = .00032). Conclusion: Our study confirms the high expression of Glut-1 not only in endometrioid carcinomas but also in other carcinomas of endometrium including clear cell and serous types. Glut-1 expression can be used as a surrogate marker in differential diagnosis between hyperplasia with and without atypia. Because of common Glut-1 expression in malignant tumors, therapeutic strategies influencing this protein or its signaling pathways can be beneficial.

Atypical nodular astrocytosis in simian immunodeficiency virus-infected rhesus macaques (Macaca mulatta)

BACKGROUND

Simian immunodeficiency virus (SIV), a model for HIV pathogenesis, is associated with neuropathology.

METHODS

Five SIV-infected animals were selected following a database search of 1206 SIV-infected animals for nodular or astrocytic lesions. Two of five had neurologic dysfunction, and 3 of 5 were incidental findings.

RESULTS

Histologic examination revealed multifocal nodular foci in the gray and white matter formed by interlacing astrocytes with abundant cytoplasm and large, reactive nuclei. Nodules were often enmeshed with small capillaries. Immunohistochemistry revealed variable immunoreactivity for a panel of markers: GFAP (4/5), vimentin (5/5), Glut-1 (1/5), CNPase (0/5), S100 (5/5), Iba1 (0/5), Ki67 (0/5), and p53 (4/4). In situ hybridization failed to detect any SIV RNA (0/5). Immunohistochemistry for simian virus 40, rhesus cytomegalovirus, and rhesus lymphocryptovirus failed to detect any antigen within the lesions.

CONCLUSION

The immunoreactivity of p53 in the lesions compared with adjacent tissue suggests a local derangement in astrocyte proliferation and function.

Expression of cyclooxygenase-2, glucose transporter-1 and angiogenesis in gallbladder carcinomas and their impact on prognosis

OBJECTIVE

To investigate the angiogenic and prognostic role of cyclooxygenase-2 (COX-2) in gallbladder carcinomas. We assume COX-2 overexpression, neoangiogenesis and glucose transporter-1 (GLUT-1) to be involved in disease progression.

MATERIAL AND METHODS

The carcinoma tissues of 56 patients with gallbladder carcinomas were studied immunohistochemically for the expression of COX-2, GLUT-1 and micro-vessel density. The results were correlated with clinico-pathological features and survival/prognosis.

RESULTS

The overexpression of COX-2 in gallbladder carcinomas was significantly associated with increased angiogenesis and GLUT-1 expression. Neither angiogenesis nor the grade of the tumour correlate significantly with poor survival. Age, gender and a strong GLUT-1 expression were significant factors of adverse prognosis.

CONCLUSIONS

Next to age and gender of patients, hypoxia of gallbladder tumours is a factor influencing survival. Among hypoxic factors, GLUT-1 expression is an important (significant) denominator of poor prognosis in gallbladder carcinomas, but not COX-2 nor angiogenesis.

Significance of concurrent endometrial cancer in women with a preoperative diagnosis of atypical endometrial hyperplasia

OBJECTIVES

Our objectives were (1) to review the rate of concurrent endometrial cancer in patients with a preoperative diagnosis of atypical endometrial hyperplasia (AEH); (2) to determine the proportion of patients with concurrent endometrial cancer who have high-risk disease; and (3) to re-evaluate our surgical management of AEH.

METHODS

We performed a retrospective chart review of all patients who had surgery on the basis of a preoperative diagnosis of atypical endometrial hyperplasia between January 2001 and December 2006. Demographic data, the method of preoperative diagnosis, postoperative grade of tumour, and other postoperative findings were recorded. When applicable, this included cancer stage, lymph node status, and presence of lymphovascular space invasion. In postoperative review, patients were considered to be high risk if they had disease beyond the uterus or a combination of other risk factors.

RESULTS

Of 70 patients, 25 (35.7%) were found to have concurrent endometrial cancer. This was higher than the commonly accepted rate of 25% (P = 0.03). Of the 25 patients upgraded, 4 (16%) had high-risk cancer on final pathologic evaluation.

CONCLUSION

Simple hysterectomy in women with AEH may result in inadequate surgical management. Simple methods are required to identify patients with a preoperative diagnosis of AEH who may harbour significant cancers.

Immunohistochemical expression of the glucose transporters Glut-1 and Glut-3 in human malignant melanomas and benign melanocytic lesions

Background

Reported data indicate that cancer cells have increased rates of glucose metabolism, as determined by 18FDG-PET imaging in patients with malignancies. The results of many studies have demonstrated that the expression of glucose transporters, especially Glut-1, is increased in a variety of malignancies. This study was undertaken to assess the differential expression of Glut-1 and Glut-3 by benign and malignant melanocytic lesions.

Methods

Immunohistochemical staining for Glut-1 and Glut-3 was performed on paraffin-embedded tissue sections prepared from melanocytic nevi (12 cases), Spitz nevi (12 cases) and primary cutaneous malignant melanomas (20 cases).

Results

We observed immunoreactivity for Glut-1 in all melanocytic nevi, 9 of the 12 Spitz nevi and in 9 of the 20 malignant melanomas, whereas Glut-3 was expressed in all the melanocytic lesions, both benign and malignant.

Conclusion

These findings indicate that the glucose transporters Glut-1 and Glut-3 play a role in the glucose metabolism of melanocytic cells. Glut-1 was present in the majority of benign nevi, whereas its expression was downregulated in 55% of malignant melanomas. Our results suggest that glucose transporter Glut-1 expression can significantly discriminate between human malignant melanoma and benign melanocytic nevi, and support the idea that additional mechanisms other than Glut-1 may contribute to glucose uptake in melanomas.