Cancer as a Metabolic Disorder Gyamfi, Jones; Kim, Jinyoung; Choi, Junjeong
International journal of molecular sciences,
01/2022, Letnik:
23, Številka:
3
Journal Article
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Cancer has long been considered a genetic disease characterized by a myriad of mutations that drive cancer progression. Recent accumulating evidence indicates that the dysregulated metabolism in ...cancer cells is more than a hallmark of cancer but may be the underlying cause of the tumor. Most of the well-characterized oncogenes or tumor suppressor genes function to sustain the altered metabolic state in cancer. Here, we review evidence supporting the altered metabolic state in cancer including key alterations in glucose, glutamine, and fatty acid metabolism. Unlike genetic alterations that do not occur in all cancer types, metabolic alterations are more common among cancer subtypes and across cancers. Recognizing cancer as a metabolic disorder could unravel key diagnostic and treatments markers that can impact approaches used in cancer management.
The tumour microenvironment is a key regulators of tumour progression through the secretion of growth factors that activate epithelial-mesenchymal transition (EMT). Induction of EMT is a key step for ...transition from a benign state to a metastatic tumour. Adipose tissue forms a bulk portion of the breast cancer microenvironment, emerging evidence indicates the potential for adipocytes to influence tumour progression through the secretion of adipokines that can induce EMT. The molecular mechanisms underlying how adipocytes enhance breast cancer progression is largely unknown. We hypothesized that paracrine signalling by adipocytes can activate EMT and results in increased migration and invasion characteristics of breast cancer cells. We found that IL-6 secreted by adipocytes induce EMT in breast cancer cells. The effect of IL-6 expression on EMT is mediated through activation of the signal transducer and activated of transcription 3 (STAT3). Blocking of IL-6 signalling in breast cancer cells and adipocytes, decreased proliferation, migration and invasion capabilities and altered the expression of genes regulating EMT. Together, our results suggest that matured human adipocytes can enhance the aggressive behaviour of breast cancer cells and induce an EMT-phenotype through paracrine IL-6/STAT3 signalling.
The microenvironment of breast cancer comprises predominantly of adipocytes. Adipocytes drive cancer progression through the secretion adipocytokines. Adipocytes induce epithelial mesenchymal ...transition of breast cancer cells through paracrine IL-6/Stat3 signalling. Treatment approaches that can target adipocytes in the microenvironment and abrogate paracrine signals that drive breast cancer growth and metastasis are urgently needed. Repositioning of old drugs has become an effective approach for discovering new cancer drugs. In this study, niclosamide, an FDA approved anthelminthic drug was evaluated for its anti-breast cancer activity and its ability to inhibit adipocytes induced EMT. Niclosamide potently inhibited proliferation, migration and invasion at low concentration and induced significant apoptosis at high concentrations in human breast cancer cell lines MDA-MB-468 and MCF-7. Additionally, niclosamide reversed adipocyte-induced EMT with a correlated inhibition of IL-6/Stat3 activation and downregulation of EMT-TFs TWIST and SNAIL. Moreover, niclosamide markedly impaired MDA-MB-468 and MCF-7 migration and invasion. We further found that the inhibitory effects of niclosamide on MDA-MB-468 and MCF-7 motility was closely related to destabilization of focal adhesion complex formation. With decreased co-localization of focal adhesion kinase (FAK) and phosphorylated paxillin (pPAX). Collectively, these results demonstrate that niclosamide could be used to inhibit adipocyte-induced breast cancer growth and metastasis.
Abstract
Adipocytes influence breast cancer behaviour via fatty acid release into the tumour microenvironment. Co-culturing human adipocytes and breast cancer cells increased CD36 expression, with ...fatty acid import into breast cancer cells. Genetic ablation of CD36 attenuates adipocyte-induced epithelial-mesenchymal transition (EMT) and stemness. We show a feedforward loop between CD36 and STAT3; where CD36 activates STAT3 signalling and STAT3 binds to the CD36 promoter, regulating its expression. CD36 expression results in metabolic reprogramming, with a shift towards fatty acid oxidation. CD36 inhibition induces de novo lipogenesis in breast cancer cells. Increased CD36 expression occurs with increased FABP4 expression. We showed that CD36 directly interacts with FABP4 to regulate fatty acid import, transport, and metabolism. CD36 and FABP4 inhibition induces apoptosis in tumour cells. These results indicate that CD36 mediates fatty acid import from adipocytes into cancer cells and activates signalling pathways that drive tumour progression. Targeting CD36 may have a potential for therapy, which will target the tumour microenvironment.
Breast cancer is the most common malignancy in women worldwide, with a developmental process spanning decades. The malignant cells recruit a variety of cells including fibroblasts, endothelial cells, ...immune cells, and adipocytes, creating the tumor microenvironment. The tumor microenvironment has emerged as active participants in breast cancer progression and response to treatment through autocrine and paracrine interaction with the malignant cells. Adipose tissue is abundant in the breast cancer microenvironment; interactions with cancer cells create cancer-associated adipocytes which produce a variety of adipokines that influence breast cancer initiation, metastasis, angiogenesis, and cachexia. Interleukin (IL)-6 has emerged as key compound significantly produced by breast cancer cells and adipocytes, with the potential of inducing proliferation, epithelial-mesenchymal phenotype, stem cell phenotype, angiogenesis, cachexia, and therapeutic resistance in breast cancer cells. Our aim is to present a brief knowledge of IL-6’s role in breast cancer. This review summarizes our current understanding of the breast microenvironment, with emphasis on adipocytes as key players in breast cancer tumorigenesis. The effects of key adipocytes such as leptin, adipokines, TGF-b, and IL-6 are discussed. Finally, we discuss the role of IL-6 in various aspects of cancer progression.
Abstract
In accordance with the United Nations’ requirements for dealing with juvenile offenders, Ghana’s Children Act 1998 mandated local authorities to establish child panels to mediate minor ...offences committed by children. However, to date there has not been any research that has examined the functioning and effectiveness of the child panels. This research examined the operationalisation and effectiveness of child panels in Ghana. The study involved the use of semi-structured interviews and focus group discussions with panel members of four local authorities. Findings showed that the child panels are not functioning effectively in Ghana. The relevance of the child panels has been questioned since it was found to be duplicating the roles of some other child welfare agencies. This article discusses the challenges impeding the effectiveness of the child panels and outlines recommendations to improve their effectiveness.
In this study, we sought to determine whether faecal shedding occurs among SARS-COV-2 positive Ghanaians, as reported elsewhere. Hence we assayed for SARS-COV-2 in the stools of 48 SARS-COV-2 ...confirmed patients at the Ho Municipal Hospital in Ghana.
Of the 48 COVID-19 patients, 45 (93.8%) had positive tests for SARS-CoV-2 faecal shedding. About 60% reported no respiratory symptoms, while only 2% (1 patient) reported gastrointestinal (GI) symptoms in the form of nausea. Other symptoms reported included headache (57.9%), weakness (57.9%), cough (52.6%), blocked/runny nose (47.4%), fever (31.6%), sore throat (31.6%), and shortness of breath (21.1%). One person complained of nausea (5.3%) Semi-quantitative comparison of the SARS COV-2 viral loads in matched respiratory and faecal samples using the cycle threshold (CT) values revealed no statistical differences. Furthermore, the duration between collection of respiratory and faecal samples did not have any direct influence on the differences in the CT values. This suggests that treatment and use of sewage for environmental surveillance of SARS COV-2 could be a potential public health countermeasure.
Breast cancer is the most commonly diagnosed malignant tumor in women worldwide and contributes significantly as the primary cause of female cancer related mortality. Hence, research is focused on ...discovering new and effective treatment targets. The breast tumor microenvironment (TME) comprising of recruited host stromal cells and tumor cells, has recently emerged as an important player in tumor progression, with the potential for future treatment. The TME comprises immune system elements (such as macrophages and lymphocytes), cells composing blood vessel, fibroblast, myofibroblast, mesenchymal stem cells, adipocytes and extracellular matrix (ECM). Among these cells, tumor-associated macrophages (TAM) are the prominent components of TME in breast cancers. Macrophages exhibit a high plasticity in response to various external signals and participate in innate and adoptive immune responses to control numerous factors of TME. Depending on the microenvironmental signal present, macrophages are polarized into two distinct phenotypes, the classically activated (M1) or the alternative activated (M2) macrophages. Tumor-associated macrophages (TAMs) closely resemble the M2-polarized. Clinicopathological studies have suggested that TAM accumulation in tumors correlates with a poor clinical outcome. In human breast carcinomas, high TAM density correlates with poor prognosis. Over the years, studies into the role of TAMs in breast cancer progression have identified TAMs to be capable of inducing angiogenesis, remodelling the tumor extracellular matrix to aid invasion, modelling breast cancer cells to evade host immune system and recruiting immunosuppressive leukocytes to the tumor microenvironment. Along with these functions, the potential role for TAMs in activation of breast cancer stem cells (CSC) has also emerged. Thus, TAMs in breast cancer can enhance cancer cell invasion by degrading the ECM, stimulate tumor vascularization and angiogenesis and suppress the anti-tumor functions of cytotoxic T cells resulting in poor prognosis for patients. These observations make TAMs an attractive target for therapeutic intervention by targeting various aspects of their function. This review discusses the mechanisms responsible for TAM recruitment and highlights the roles of TAMs in regulating tumor angiogenesis, invasion, metastasis, immunosuppression, and chemotherapeutic resistance. Finally, the potential for TAM-targeted therapy as a promising novel strategy is also discussed.
Abstract
The role of the tumor microenvironment in tumor progression has recently gained enormous attention, with studies reporting heterogeneous interactions between tumor cells and tumor stroma ...cells driving tumor progression. The breast cancer microenvironment is unique since the breast tissue within which the tumor originates comprises predominantly of adipocytes. This makes adipocytes a unique component in the breast cancer microenvironment. Adipocytes secrete various growth factors and cytokines that influence tumor progression by induction of epithelial-mesenchymal transition (EMT) which enhances cancer cell migration, invasion and metastasis. This study presents an alternative approach by which adipocytes may enhance cancer progression via the transfer of free-fatty acids from tumor-associated adipocytes to breast cancer cells. The uptake of free fatty acid subsequently serves as a secondary source of energy to drive breast cancer progression. The study aimed to provide an in-depth understanding of the molecular mechanism by which free fatty acid are imported and metabolized in cancer cells in an adipocyte-rich microenvironment. Human adipocytes were co-cultured with cancer cells and the fatty acid (FA) translocase (CD36) activity was inhibited by the chemical inhibitor sulfosuccinimidyl oleate (SSO). Silencing RNA and expression plasmids were used to evaluate CD36 activity in cancer cells. Expression levels of key genes and proteins involved in lipid transfer and metabolism were evaluated by qtPCR and western blot. Inhibition of CD36 reduces free fatty acid uptake and induces intracellular lipogenesis with upregulation of fatty acid synthase (FASN). Breast cancer cells co-cultured with human adipocytes express high levels of the CD36 facilitating free fatty acid uptake from adipocytes. Co-cultured cells had increased levels of fatty acid oxidation (FAO) and oxygen consumption, with increased migration and invasion characteristics. We also observed a significant increase in the expression of CPT1A required for mitochondrial fatty acid import and ATGL required for triglyceride metabolism. Our findings indicate an enhanced dependence on FAO in co-cultured cancer cell. Indicating a potential bioenergetic adaptation of breast cancer cells to the adipocyte-rich microenvironment. Inhibition of CD36 and CPT1 significantly decreased breast cancer cell migration and invasion. These results suggest that cancer-associated adipocytes induce free fatty acid uptake via upregulation of CD36 and reprogram breast cancer cell metabolism. Thus, targeting CD36 may have a potential targeted therapy.
Citation Format: Junjeong Choi, Jones Gyamfi. Adipocytes up-regulates CD36 expression, fatty acid uptake and oxidation enhancing breast cancer cell progression abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2020.
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