Does TP53 mutation promote ovarian cancer metastasis to omentum by regulating lipid metabolism?

A Perspective Review: Analyzing Collagen Alterations in Ovarian Cancer by High-Resolution Optical Microscopy

High-grade serous ovarian cancer (HGSOC) is the predominant subtype of ovarian cancer (OC), occurring in more than 80% of patients diagnosed with this malignancy. Histological and genetic analysis have confirmed the secretory epithelial of the fallopian tube (FT) as a major site of origin of HGSOC. Although there have been significant strides in our understanding of this disease, early stage detection and diagnosis are still rare. Current clinical imaging modalities lack the ability to detect early stage pathogenesis in the fallopian tubes and the ovaries. However, there are several microscopic imaging techniques used to analyze the structural modifications in the extracellular matrix (ECM) protein collagen in ex vivo FT and ovarian tissues that potentially can be modified to fit the clinical setting. In this perspective, we evaluate and compare the myriad of optical tools available to visualize these alterations and the invaluable insights these data provide on HGSOC initiation. We also discuss the clinical implications of these findings and how these data may help novel tools for early diagnosis of HGSOC.

Alterations in mitochondria isolated from peripheral blood mononuclear cells and tumors of patients with epithelial ovarian cancers

Metabolic alterations play an essential role in ovarian carcinogenesis. The flexibility of mitochondrial functions facilitates cellular adaptation to the tough environment associated with carcinogenesis. An understanding of the differences in mitochondrial functions in normal ovaries and cancers could provide a basis for further exploration of future mitochondria-based screening, diagnosis, prognostic prediction, and targeted therapy for epithelial ovarian cancers. The main objective of this study was to assess mitochondrial function profiles measured from PBMCs and ovarian tissues of epithelial ovarian cancers in comparison with normal ovaries. A total of 36 patients were recruited for the study, all of whom underwent primary surgical treatment for malignant epithelial ovarian neoplasm. Of these, 20 patients were in the early stage and 16 patients were in the advanced stage. Additionally, 21 patients who had pelvic surgery for benign gynecologic conditions, with normal ovaries incidentally removed, were recruited as controls. At the time of surgery, a blood sample was collected from each participant for PBMC isolation, and ovarian tissue was retained for molecular studies. These studies included the examination of oxidative stress, mitochondrial mass, mitochondrial respiration, mitochondrial reactive oxygen species (ROS), mitochondrial membrane potential (MMP) changes, and mitochondrial swelling. Clinical and histopathological data were also collected and compared between different stages of epithelial ovarian cancers: early-stage (group 1), advanced-stage (group 2), and normal ovaries (group 3). The levels of cellular oxidative stress, mitochondrial mass, and mitochondrial biogenesis in the peripheral blood mononuclear cells (PBMCs) of participants with ovarian cancer were significantly lower than those of the control group. However, the mitochondrial respiratory parameters measured from the PBMCs were similar across all three groups. Furthermore, mitochondrial membrane depolarization and mitochondrial swelling were observed in ovarian tissues of both early-stage and advanced-stage cancer groups. We demonstrated the dynamic nature of mitochondrial ROS production, biogenesis, and respiratory function in response to epithelial ovarian carcinogenesis. The flexibility of mitochondrial functions under diverse conditions may make it a challenging therapeutic target for ovarian cancer.

Effect of Shan Zha (Hawthorn or Crataegus) on gastrointestinal cancer: A network pharmacology and molecular docking study

Background

Shan Zha (Hawthorn or Crataegus) is a traditional Chinese medicine (TCM) most commonly used for the treatment of hyperlipidemia. Gastrointestinal cancer is closely correlated with blood lipid levels. This study illustrates the potential anticancer effects of Shan Zha on gastrointestinal tumors based on network pharmacology and molecular docking.

Methods

Hawthorn's bioactive ingredients and drug targets were obtained from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), Integrative Pharmacology-based Research Platform of Traditional Chinese Medicine version 2.0 (TCMIP v2.0), and Herbal Ingredients' Targets Platform (HIT 2.0) databases. Validated disease targets of gastrointestinal cancer were obtained from the Therapeutic Targets Database (TTD) and HIT 2.0 databases. Protein-protein interaction analysis of intersecting genes was performed using the Search Tool for the Retrieval of Interacting Genes (STRING) database. The functions of these genes were further analyzed by performing gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Molecular docking verification was performed using Molecular Operating Environment (MOE) software.

Results

Four main bioactive components were identified in Shan Zha. A total of 271 potential drug targets were identified, and 393 gastrointestinal-tumor targets were obtained. Through protein interaction analysis of intersecting targets, the main components of Shan Zha were found to interact more closely with proteins such as tumor protein p53 (TP53), AKT serine/threonine kinase 1 (AKT1), JUN proto-oncogene (JUN), interleukin 6 (IL6), epidermal growth factor receptor (EGFR), and vascular endothelial growth factor A (VEGFA). KEGG pathway enrichment analysis showed a total of 127 pathways, mainly involving pathways in multiple types of cancer, the Phosphatidylinositol 3-kinase-Akt (PI3K-Akt) signaling pathway, and EGFR tyrosine kinase inhibitor resistance. Combined with The Cancer Genome Atlas (TCGA) differential analysis, key targets, including TP53, cyclin D1 (CCND1), EGFR, and VEGFA, were screened. Molecular docking results showed that quercetin and kaempferol had the good binding potential for TP53, CCND1, EGFR, and VEGFA.

Conclusion

These findings suggest that Shan Zha exerts its effects on gastrointestinal cancers through a multitarget, multi-component, and a multi-pathway mechanism.

Application of tumor-educated platelets as new fluid biopsy markers in various tumors

The incidence of malignant tumors is increasing year by year. Early detection and diagnosis of malignant tumors can improve the prognosis of patients and prolong their life. Pathological biopsy is the current gold standard for diagnosis, but the results of pathological biopsy are affected by the sampling site and cannot fully reflect the nature of the disease. Moreover, the invasive nature of pathological biopsy limits repeated detection. Liquid biopsies are non-invasive and can be used for early detection and monitoring of tumors, which considered to represent a promising tool. Platelets make themselves to be one of the richest liquid biopsy sources by the capacity to take up proteins and nucleic acids and alter their megakaryocyte-derived transcripts and proteins in response to external signals, which are called tumor-educated platelets (TEPs). In this article, we will review the application of tumor-educated platelets in various malignancies (nasopharyngeal carcinoma, prostate cancer, lung cancer, glioblastoma, colorectal cancer, pancreas cancer, ovarian cancer, sarcoma, breast cancer and hepatocellular carcinoma) and provide theoretical basis for the research of TEPs in tumor diagnosis, monitoring and treatment.

Clinical outcomes of immunohistochemistry of the p53 Staining pattern in high-grade serous ovarian carcinoma

Objective

To investigate the prevalence of p53 mutations and associated factors between immunohistochemistry (IHC) and p53 staining patterns among patients with high-grade serous ovarian carcinoma (HGSOC).

Methods

This study is a retrospective review. A total of 62 patients with HGSOC underwent surgery at Srinagarind Hospital between January 2016 and December 2020. Histological examination was performed based on a combination of morphology and IHC staining with p53. The p53 immunostaining pattern was interpreted as a missense mutation, nonsense mutation, or a wild-type pattern. Missense (p53 overexpression pattern) and nonsense (null expression p53 pattern) mutations were considered p53 mutations. A wild-type pattern was defined as a p53 non-mutation.

Results

p53 mutations were identified in 93.6% of the patients. Subgroup analysis of the p53 mutation group between the p53 overexpression pattern and the p53 null expression pattern in terms of clinicopathological characteristics and initial treatment was performed. Patients with the p53 overexpression pattern had significantly more omental metastases than those with the p53 null expression pattern (87.8% vs. 64.7%, P=0.042). There were no statistically significant differences in median progression-free survival (PFS) (9 vs. 10 months, P=0.813) or median overall survival (OS) (12 vs. 17 months, P=0.526) between the two groups.

Conclusion

The prevalence of p53 mutations in HGSOC patients in this study was 93.6%. Omental metastasis is a significant pathological factor in predicting overexpression p53 pattern in HGSC. However, IHC analysis of the p53 staining pattern did not affect OS or PFS among patients with HGSOC.

A Cholesterol Homeostasis-Related Gene Signature Predicts Prognosis of Endometrial Cancer and Correlates With Immune Infiltration

Background: Endometrial cancer (EC) is one of the most common gynecological malignancies in women. Cholesterol metabolism has been confirmed to be closely related to tumor proliferation, invasion and metastasis. However, the correlation between cholesterol homeostasis-related genes and prognosis of EC remains unclear.

Methods: EC patients from the Cancer Genome Atlas (TCGA) database were randomly divided into training cohort and test cohort. Transcriptome analysis, univariate survival analysis and LASSO Cox regression analysis were adopted to construct a cholesterol homeostasis-related gene signature from the training cohort. Subsequently, Kaplan-Meier (KM) plot, receiver operating characteristic (ROC) curve and principal component analysis (PCA) were utilized to verify the predictive performance of the gene signature in two cohorts. Additionally, enrichment analysis and immune infiltration analysis were performed on differentially expressed genes (DEGs) between two risk groups.

Results: Seven cholesterol homeostasis-related genes were selected to establish a gene signature. KM plot, ROC curve and PCA in two cohorts demonstrated that the gene signature was an efficient independent prognostic indicator. The enrichment analysis and immune infiltration analysis indicated that the high-risk group generally had lower immune infiltrating cells and immune function.

Conclusion: We constructed and validated a cholesterol homeostasis-related gene signature to predict the prognosis of EC, which correlated to immune infiltration and expected to help the diagnosis and precision treatment of EC.

Induction of microRNA hsa-let-7d-5p, and repression of HMGA2, contribute protection against lipid accumulation in macrophage 'foam' cells

Accumulation of excess cholesterol and cholesteryl ester in macrophage 'foam' cells within the arterial intima characterises early 'fatty streak' atherosclerotic lesions, and is accompanied by epigenetic changes, including altered expression of microRNA sequences which determine of gene and protein expression. This study established that exposure to lipoproteins, including acetylated LDL, induced macrophage expression of microRNA hsa-let-7d-5p, a sequence previously linked with tumour suppression, and repressed expression of one of its target genes, high mobility group AT hook 2 (HMGA2). A let-7d-5p mimic repressed expression of HMGA2 (18%; p < 0.05) while a marked increase (2.9-fold; p < 0.05) in expression of HMGA2 was noted in the presence of let-7d-5p inhibitor. Under these conditions, let-7d-5p mimic significantly (p < 0.05) decreased total (10%), free (8%) and cholesteryl ester (21%) mass, while the inhibitor significantly (p < 0.05) increased total (29%) and free cholesterol (29%) mass, compared with the relevant controls. Let-7d-5p inhibition significantly (p < 0.05) increased endogenous biosynthesis of cholesterol (38%) and cholesteryl ester (39%) pools in macrophage 'foam' cells, without altering the cholesterol efflux pathway, or esterification of exogenous radiolabelled oleate. Let-7d-5p inhibition in sterol-loaded cells increased the level of HMGA2 protein (32%; p < 0.05), while SiRNA knockdown of this protein (29%; p < 0.05) resulted in a (21%, p < 0.05) reduction in free cholesterol mass. Thus, induction of let-7d-5p, and repression of its target HMGA2, in macrophages is a protective response to the challenge of increased cholesterol influx into these cells; dysregulation of this response may contribute to atherosclerosis and other disorders such as cancer.

Differentiated pre-adipocytes promote proliferation, migration and epithelial-mesenchymal transition in breast cancer cells of different p53 status

Breast cancer progression and metastasis are associated with stromal cells in the tumor microenvironment. Adipocytes are the most abundant cells surrounding breast stromal tissue, promote tumor progression through the induction of Epithelial-to-Mesenchymal Transition (EMT) which is negatively regulated by tumor suppressor protein p53. In this study aimed to investigate the role of p53 in the progression of breast cancer after mature adipocyte-conditioned medium (CM) application. The proliferative effect of CM obtained from differentiated pre-adipocytes were assessed by MTS assay. 20% CM increased cell proliferation in breast cancer cells, T-47D (mutant p53) and MCF-7 (wild-type p53). The migration and invasion capacity were evaluated by scratch and transwell assays, respectively. CM significantly enhanced migration and invasion capacity in T-47D compared to MCF-7. Gene and protein expressions were detected by qRT-PCR and Western Blot analysis, respectively. CM markedly increased expression levels of Cyclin D1, PI3K, MMP9, Snail and Twist in T-47D compared to MCF-7. However, CM did not change E-Cadherin level in T-47D while downregulated in MCF-7 cells. Also, the protein levels of NFκB p65, p-Akt, Snail, and Vimentin were upregulated in both cells. Overall, the findings highlight how the p53 status affects mature adipocyte-mediated proliferation, migration, and aggressive behavior of breast cancer cell lines. Targeting the tumor microenvironment may represent a promising approach for preventing breast cancer progression and metastasis.

Bioinformatics analysis of FOLR1 expression, functional enrichment, related signaling pathways and relationship with prognosis in ovarian cancer

Objective To investigate folate-receptor 1 (FOLR1) expression in ovarian cancer and its association with patient prognosis.

Methods TCGA and Oncomine databases were used to collect data about FOLR1 mRNA expression in multiple carcinomas. FOLR1 mRNA expression levels in ovarian cancer samples and corresponding adjacent normal ovary tissue were compared. A protein-protein interaction (PPI) network was constructed using the STRING database of FOLR1 and relevant genes. The overall survival (OS) and progression free survival (PFS) rates of ovarian cancer patients in high- and low- FOLR1 expression groups were compared by log-rank test. Sixty-six ovarian epithelial carcinoma samples were included in the study, and tumor specimens of the 66 cases were tested for FOLR1 protein expression by an immunohistochemistry assay.

Results FOLR1 mRNA was significantly elevated in ovarian cancer compared to other carcinomas. FOLR1 mRNA expression levels were significantly higher in tumor tissues than in the corresponding normal tissues (P<0.05) of ovarian cancer patients. The PPI network indicated that the local clustering coefficient was 0.898, indicating that the PPI network was enriched significantly (P<0.05). The median PFS values were 22.39 and 19.00 months for lowand high-FOLR1 expression groups, respectively, with significant statistical difference between the two (HR=1.26, 95%CI:1.09-1.45, P<0.05). FOLR1 protein expression was correlated with tumor differentiation (P<0.05) in ovarian cancer patients. However, its levels were not correlated with patient age, tumor diameter, lymph node metastasis or FIGO stage (P>0.05).

Conclusion FOLR1 is upregulated in epithelial ovarian cancer, and its expression is correlated with patients’ progression free survival, making it a valuable biomarker for prognosis.

New Insights Into the Role of Phenotypic Plasticity and EMT in Driving Cancer Progression

Tumor cells demonstrate substantial plasticity in their genotypic and phenotypic characteristics. Epithelial-mesenchymal plasticity (EMP) can be characterized into dynamic intermediate states and can be orchestrated by many factors, either intercellularly via epigenetic reprograming, or extracellularly via growth factors, inflammation and/or hypoxia generated by the tumor stromal microenvironment. EMP has the capability to alter phenotype and produce heterogeneity, and thus by changing the whole cancer landscape can attenuate oncogenic signaling networks, invoke anti-apoptotic features, defend against chemotherapeutics and reprogram angiogenic and immune recognition functions. We discuss here the role of phenotypic plasticity in tumor initiation, progression and metastasis and provide an update of the modalities utilized for the molecular characterization of the EMT states and attributes of cellular behavior, including cellular metabolism, in the context of EMP. We also summarize recent findings in dynamic EMP studies that provide new insights into the phenotypic plasticity of EMP flux in cancer and propose therapeutic strategies to impede the metastatic outgrowth of phenotypically heterogeneous tumors.

Roles of omental and bone marrow adipocytes in tumor biology

Accumulating evidence highlights the importance of interactions between tumour cells and stromal cells for tumour initiation, progression, and metastasis. In tumours that contain adipocyte in their stroma, adipocytes contribute to modification of tumour microenvironment and affect metabolism of tumour and tumour progression by production of cytokines and adipokines from the lipids. The omentum and bone marrow (BM) are highly adipocyte-rich and are also common metastatic and primary tumour developmental sites. Omental adipocytes exhibit metabolic cross-talk, immune modulation, and angiogenesis. BM adipocytes secrete adipokines, and participate in solid tumour metastasis through regulation of the CCL2/CCR2 axis and metabolic interactions. BM adipocytes also contribute to the progression of hematopoietic neoplasms. Here, we here provide an overview of research progress on the cross-talks between omental/BM adipocytes and tumour cells, which may be pivotal modulators of tumour biology, thus highlighting novel therapeutic targets.

Abbreviations: MCP-1, monocyte chemoattractant protein 1IL, interleukinSTAT3, signal transducer and activator of transcription 3FABP4, fatty acid binding protein 4PI3K/AKT, phosphoinositide 3-kinase/protein kinase BPPAR, peroxisome proliferator-activated receptorPUFA, polyunsaturated fatty acidTAM, tumour-associated macrophagesVEGF, vascular endothelial growth factorVEGFR, vascular endothelial growth factor receptorBM, bone marrowBMA, bone marrow adipocytesrBMA, regulated BMAcBMA, constitutive BMAUCP-1, uncoupling protein-1TNF-α, tumour necrosis factor-alphaRANKL, receptor activator of nuclear factor kappa-Β ligandVCAM-1, vascular cell adhesion molecule 1JAK2, Janus kinase 2CXCL (C–X–C motif) ligandPGE2, prostaglandin E2COX-2, cyclooxygenase-2CCL2, C-C motif chemokine ligand 2NF-κB, nuclear factor-kappa BMM, multiple myelomaALL, acute lymphoblastic leukemiaAML, acute myeloid leukemiaGDF15, growth differentiation factor 15AMPK, AMP-activated protein kinaseMAPK, mitogen-activated protein kinaseAPL, acute promyelocytic leukemiaCCR2, C-C motif chemokine receptor 2SDF-1α, stromal cell-derived factor-1 alphaFFA, free fatty acidsLPrA, leptin peptide receptor antagonistMCD, malonyl-CoA decarboxylase.

Simvastatin interferes with cancer 'stem-cell' plasticity reducing metastasis in ovarian cancer

Cell plasticity of 'stem-like' cancer-initiating cells (CICs) is a hallmark of cancer, allowing metastasis and cancer progression. Here, we studied whether simvastatin, a lipophilic statin, could impair the metastatic potential of CICs in high-grade serous ovarian cancer (HGS-ovC), the most lethal among the gynecologic malignancies. qPCR, immunoblotting and immunohistochemistry were used to assess simvastatin effects on proteins involved in stemness and epithelial-mesenchymal cell plasticity (EMT). Its effects on tumor growth and metastasis were evaluated using different models (e.g., spheroid formation and migration assays, matrigel invasion assays, 3D-mesomimetic models and cancer xenografts). We explored also the clinical benefit of statins by comparing survival outcomes among statin users vs non-users. Herein, we demonstrated that simvastatin modifies the stemness and EMT marker expression patterns (both in mRNA and protein levels) and severely impairs the spheroid assembly of CICs. Consequently, CICs become less metastatic in 3D-mesomimetic models and show fewer ascites/tumor burden in HGS-ovC xenografts. The principal mechanism behind statin-mediated effects involves the inactivation of the Hippo/YAP/RhoA pathway in a mevalonate synthesis-dependent manner. From a clinical perspective, statin users seem to experience better survival and quality of life when compared with non-users. Considering the high cost and the low response rates obtained with many of the current therapies, the use of orally or intraperitoneally administered simvastatin offers a cost/effective and safe alternative to treat and potentially prevent recurrent HGS-ovCs.

p53 and metabolism: from mechanism to therapeutics

The tumor cell changes itself and its microenvironment to adapt to different situations, including action of drugs and other agents targeting tumor control. Therefore, metabolism plays an important role in the activation of survival mechanisms to keep the cell proliferative potential. The Warburg effect directs the cellular metabolism towards an aerobic glycolytic pathway, despite the fact that it generates less adenosine triphosphate than oxidative phosphorylation; because it creates the building blocks necessary for cell proliferation. The transcription factor p53 is the master tumor suppressor; it binds to more than 4,000 sites in the genome and regulates the expression of more than 500 genes. Among these genes are important regulators of metabolism, affecting glucose, lipids and amino acids metabolism, oxidative phosphorylation, reactive oxygen species (ROS) generation and growth factors signaling. Wild-type and mutant p53 may have opposing effects in the expression of these metabolic genes. Therefore, depending on the p53 status of the cell, drugs that target metabolism may have different outcomes and metabolism may modulate drug resistance. Conversely, induction of p53 expression may regulate differently the tumor cell metabolism, inducing senescence, autophagy and apoptosis, which are dependent on the regulation of the PI3K/AKT/mTOR pathway and/or ROS induction. The interplay between p53 and metabolism is essential in the decision of cell fate and for cancer therapeutics.

Elevated expression of FABP3 and FABP4 cooperatively correlates with poor prognosis in non-small cell lung cancer (NSCLC)

Fatty acid binding proteins (FABPs) are intracellular lipid-binding proteins that are involved in a variety of biological cellular processes, including tumorigenesis. In this study, we explored the expression pattern of FABP3 and FABP4 in non-small cell lung cancer (NSCLC) as well as their roles in prognosis. We determined mRNA expression of FABP3 and FABP4 in matched pairs of cancerous and non-cancerous fresh frozen tissues from 30 NSCLC patients. Tissue microarray immunohistochemical analysis (TMA-IHC) was applied to determine the protein expression of FABP3 and FABP4 in 281 cancerous and 121 matched adjacent non-cancerous tissue samples. Our results showed that both mRNA and protein expression of FABP3 and FABP4 were significantly higher in cancerous tissues when compared to non-cancerous tissues. Furthermore, high expression of FABP3 or FABP4 in NSCLC was significantly associated with advanced tumor node metastasis (TNM) stage and had a negative impact on the overall survival of NSCLC patients. Concurrent high expression of FABP3 and FABP4 was significantly related to TNM stage. In conclusion, our research demonstrated that high FABP3 or FABP4 expression had strong prognostic value for overall survival in NSCLC. Detection of FABP3 and FABP4 cooperatively was helpful to predict the prognosis of NSCLC.

Adipocytes promote cholangiocarcinoma metastasis through fatty acid binding protein 4

Background

The early occurrence regional nodal and distant metastases cholangiocarcinoma (CCA) is one of the major reasons for its poor prognosis. However, the related mechanisms are largely elusive. Recently, increasing evidences indicate that adipocytes might be involved in the proliferation, homing, migration and invasion of several malignancies. In the present study, we attempt to determine the effects and possible mechanisms of adipocytes on regulating progression of CCA.

Methods

Adipocyte–CCA cell co-culture system and CCA metastasis mice model were used to determine the effects of adipocytes on CCA metastasis. We identified the biological functions and possible mechanisms of adipocyte-derived fatty acid binding protein 4 (FABP4) in regulating the adipocyte-induced CCA metastasis and epithelial-mesenchymal transition (EMT) phenotypes, both in vitro and in vivo.

Results

Adipocyte–CCA cell co-culture promotes the in vitro and in vivo tumor metastasis, leading to increased adipocyte-derived fatty acid absorbance and intracellular lipids of CCA cells, which indicates adipocytes might function as the energy source for CCA progression by providing free fatty acids. Further, highly expressed FABP4 protein was identified in adipose tissues and fully differentiated adipocytes, and upregulated FABP4 was also detected by qRT-PCR assay in CCA cells co-cultivated with adipose extracts as compared to parental CCA cells. The specific FABP4 inhibitor BMS309403 significantly impaired adipocyte-induced CCA metastasis and EMT phenotypes both in vitro and in vivo.

Conclusions

Together, the results demonstrate that the adipocyte-CCA interaction and the energy extraction of CCA cells from adipocytes are crucial for the invasion, migration and EMT of CCA cells. FABP4 from adipocytes mediates these adipocyte-induced variations in CCA cells, which could serve as a potential target for the treatment of CCA.

Electronic supplementary material

The online version of this article (10.1186/s13046-017-0641-y) contains supplementary material, which is available to authorized users.

Highly-accurate metabolomic detection of early-stage ovarian cancer

High performance mass spectrometry was employed to interrogate the serum metabolome of early-stage ovarian cancer (OC) patients and age-matched control women. The resulting spectral features were used to establish a linear support vector machine (SVM) model of sixteen diagnostic metabolites that are able to identify early-stage OC with 100% accuracy in our patient cohort. The results provide evidence for the importance of lipid and fatty acid metabolism in OC and serve as the foundation of a clinically significant diagnostic test.

[Advances in the relationship between tumor cell metabolism and tumor metastasis]

Intracellular nutrients and the rate of energy flowing in tumor cells are often higher than that in normal cells due to the prolonged stress of tumor-specific microenvironment. In this context, the metabolism of tumor cells provides the fuel of bio-synthesis and energy required for tumor metastasis. Consistent with this, the abnormal metabolism such as extremely active glucose metabolism and excessive accumulating of fatty acid is also discovered in metastatic tumors. Previous Studies have confirmed that the regulation of tumor metabolism can affect the tumor metastasis, and some of these have been successfully applied in clinical effective, positive way. Thus, targeting metabolism of tumor cells might be an effectively positive way to prevent the metastasis of tumor. So, our review is focused on the research development of the relationship between tumor metabolism and metastasis as well as the underlying mechanism.

Nitric oxide mediates metabolic coupling of omentum-derived adipose stroma to ovarian and endometrial cancer cells

Omental adipose stromal cells (O-ASC) are a multipotent population of mesenchymal stem cells contained in the omentum tissue that promote endometrial and ovarian tumor proliferation, migration, and drug resistance. The mechanistic underpinnings of O-ASCs' role in tumor progression and growth are unclear. Here, we propose a novel nitric oxide (NO)-mediated metabolic coupling between O-ASCs and gynecologic cancer cells in which O-ASCs support NO homeostasis in malignant cells. NO is synthesized endogenously by the conversion of l-arginine into citrulline through nitric oxide synthase (NOS). Through arginine depletion in the media using l-arginase and NOS inhibition in cancer cells using N(G)-nitro-l-arginine methyl ester (l-NAME), we demonstrate that patient-derived O-ASCs increase NO levels in ovarian and endometrial cancer cells and promote proliferation in these cells. O-ASCs and cancer cell cocultures revealed that cancer cells use O-ASC-secreted arginine and in turn secrete citrulline in the microenvironment. Interestingly, citrulline increased adipogenesis potential of the O-ASCs. Furthermore, we found that O-ASCs increased NO synthesis in cancer cells, leading to decrease in mitochondrial respiration in these cells. Our findings suggest that O-ASCs upregulate glycolysis and reduce oxidative stress in cancer cells by increasing NO levels through paracrine metabolite secretion. Significantly, we found that O-ASC-mediated chemoresistance in cancer cells can be deregulated by altering NO homeostasis. A combined approach of targeting secreted arginine through l-arginase, along with targeting microenvironment-secreted factors using l-NAME, may be a viable therapeutic approach for targeting ovarian and endometrial cancers.

Role of abnormal lipid metabolism in development, progression, diagnosis and therapy of pancreatic cancer

There is growing evidence that metabolic alterations play an important role in cancer development and progression. The metabolism of cancer cells is reprogrammed in order to support their rapid proliferation. Elevated fatty acid synthesis is one of the most important aberrations of cancer cell metabolism. An enhancement of fatty acids synthesis is required both for carcinogenesis and cancer cell survival, as inhibition of key lipogenic enzymes slows down the growth of tumor cells and impairs their survival. Based on the data that serum fatty acid synthase (FASN), also known as oncoantigen 519, is elevated in patients with certain types of cancer, its serum level was proposed as a marker of neoplasia. This review aims to demonstrate the changes in lipid metabolism and other metabolic processes associated with lipid metabolism in pancreatic ductal adenocarcinoma (PDAC), the most common pancreatic neoplasm, characterized by high mortality. We also addressed the influence of some oncogenic factors and tumor suppressors on pancreatic cancer cell metabolism. Additionally the review discusses the potential role of elevated lipid synthesis in diagnosis and treatment of pancreatic cancer. In particular, FASN is a viable candidate for indicator of pathologic state, marker of neoplasia, as well as, pharmacological treatment target in pancreatic cancer. Recent research showed that, in addition to lipogenesis, certain cancer cells can use fatty acids from circulation, derived from diet (chylomicrons), synthesized in liver, or released from adipose tissue for their growth. Thus, the interactions between de novo lipogenesis and uptake of fatty acids from circulation by PDAC cells require further investigation.