GPI/AMF inhibition blocks the development of the metastatic phenotype of mature multi-cellular tumor spheroids

Two-Dimensional-PAGE Coupled with nLC-MS/MS-Based Identification of Differentially Expressed Proteins and Tumorigenic Pathways in MCF7 Breast Cancer Cells Transfected for JTB Protein Silencing

The identification of new cancer-associated genes/proteins, the characterization of their expression variation, the interactomics-based assessment of differentially expressed genes/proteins (DEGs/DEPs), and understanding the tumorigenic pathways and biological processes involved in BC genesis and progression are necessary and possible by the rapid and recent advances in bioinformatics and molecular profiling strategies. Taking into account the opinion of other authors, as well as based on our own team's in vitro studies, we suggest that the human jumping translocation breakpoint (hJTB) protein might be considered as a tumor biomarker for BC and should be studied as a target for BC therapy. In this study, we identify DEPs, carcinogenic pathways, and biological processes associated with JTB silencing, using 2D-PAGE coupled with nano-liquid chromatography tandem mass spectrometry (nLC-MS/MS) proteomics applied to a MCF7 breast cancer cell line, for complementing and completing our previous results based on SDS-PAGE, as well as in-solution proteomics of MCF7 cells transfected for JTB downregulation. The functions of significant DEPs are analyzed using GSEA and KEGG analyses. Almost all DEPs exert pro-tumorigenic effects in the JTBlow condition, sustaining the tumor suppressive function of JTB. Thus, the identified DEPs are involved in several signaling and metabolic pathways that play pro-tumorigenic roles: EMT, ERK/MAPK, PI3K/AKT, Wnt/β-catenin, mTOR, C-MYC, NF-κB, IFN-γ and IFN-α responses, UPR, and glycolysis/gluconeogenesis. These pathways sustain cancer cell growth, adhesion, survival, proliferation, invasion, metastasis, resistance to apoptosis, tight junctions and cytoskeleton reorganization, the maintenance of stemness, metabolic reprogramming, survival in a hostile environment, and sustain a poor clinical outcome. In conclusion, JTB silencing might increase the neoplastic phenotype and behavior of the MCF7 BC cell line. The data is available via ProteomeXchange with the identifier PXD046265.

Erythrose inhibits the progression to invasiveness and reverts drug resistance of cancer stem cells of glioblastoma

Glioblastoma (GBM) is the most frequent brain cancer and more lethal than other cancers. Characteristics of this cancer are its high drug resistance, high recurrence rate and invasiveness. Invasiveness in GBM is related to overexpression of matrix metalloproteinases (MMPs) which are mediated by wnt/β-catenin and induced by the activation of signaling pathways extracellularly activated by the cytokine neuroleukin (NLK) in cancer stem cells (CSC). Therefore, in this work we evaluated the effect of the tetrose saccharide, erythrose (Ery), a NLK inhibitor of invasiveness and drug sensitization in glioblastoma stem cells (GSC). GSC were obtained from parental U373 cell line by a CSC phenotype enrichment protocol based on microenvironmental stress conditions such as hypoxia, hipoglycemia, drug exposition and serum starvation. Enriched fraction of GSC overexpressed the typical markers of brain CSC: low CD133+ and high CD44; in addition, epithelial to mesenchyme transition (EMT) markers and MMPs were increased several times in GSC vs. U373 correlating with higher invasiveness, elongated and tubular mitochondrion and temozolomide (TMZ) resistance. IC₅₀ of Ery was found at nM concentration and at 24 h induced a severe diminution of EMT markers, MMPs and invasiveness in GSC. Furthermore, the phosphorylation pattern of NLK after Ery exposition also was affected. In addition, when Ery was administered to GSC at subIC₅₀, it was capable of reverting TMZ resistance at concentrations innocuous to non-tumor cancer cells. Moreover, Ery added daily induced the death of all GSC. Those findings indicated that the phytodrug Ery could be used as adjuvant therapy in GBM.

17-β Estradiol up-regulates energy metabolic pathways, cellular proliferation and tumor invasiveness in ER+ breast cancer spheroids

Several biological processes related to cancer malignancy are regulated by 17-β estradiol (E2) in ER+-breast cancer. To establish the role of E2 on the atypical cancer energy metabolism, a systematic study analyzing transcription factors, proteins, and fluxes associated with energy metabolism was undertaken in multicellular tumor spheroids (MCTS) from human ER+ MCF-7 breast cancer cells. At E2 physiological concentrations (10 and 100 nM for 24 h), both ERα and ERβ receptors, and their protein target pS2, increased by 0.6-3.5 times vs. non-treated MCTS, revealing an activated E2/ER axis. E2 also increased by 30-470% the content of several transcription factors associated to mitochondrial biogenesis and oxidative phosphorylation (OxPhos) (p53, PGC1-α) and glycolytic pathways (HIF1-α, c-MYC). Several OxPhos and glycolytic proteins (36-257%) as well as pathway fluxes (48-156%) significantly increased being OxPhos the principal ATP cellular supplier (>75%). As result of energy metabolism stimulation by E2, cancer cell migration and invasion processes and related proteins (SNAIL, FN, MM-9) contents augmented by 24-189% vs. non-treated MCTS. Celecoxib at 10 nM blocked OxPhos (60%) as well as MCTS growth, cell migration and invasiveness (>40%); whereas the glycolytic inhibitor iodoacetate (0.5 µM) and doxorubicin (70 nM) were innocuous. Our results show for the first time using a more physiological tridimensional cancer model, resembling the initial stages of solid tumors, that anti-mitochondrial therapy may be useful to deter hormone-dependent breast carcinomas.

Enrichment of Prevotella intermedia in human colorectal cancer and its additive effects with Fusobacterium nucleatum on the malignant transformation of colorectal adenomas

Background

Owing to the heterogeneity of microbiota among individuals and populations, only Fusobacterium nucleatum and Bacteroides fragilis have been reported to be enriched in colorectal cancer (CRC) in multiple studies. Thus, the discovery of additional bacteria contributing to CRC development in various populations can be expected. We aimed to identify bacteria associated with the progression of colorectal adenoma to carcinoma and determine the contribution of these bacteria to malignant transformation in patients of Han Chinese origin.

Methods

Microbiota composition was determined through 16S rRNA V3–V4 amplicon sequencing of autologous adenocarcinomas, adenomatous polyps, and non-neoplastic colon tissue samples (referred to as “tri-part samples”) in patients with CRC. Enriched taxa in adenocarcinoma tissues were identified through pairwise comparison. The abundance of candidate bacteria was quantified through genomic quantitative polymerase chain reaction (qPCR) in tissue samples from 116 patients. Associations of candidate bacteria with clinicopathological features and genomic and genetic alterations were evaluated through odds ratio tests. Additionally, the effects of candidate bacteria on CRC cell proliferation, migration, and invasion were evaluated through the co-culture of CRC cells with bacterial cells or with conditioned media from bacteria.

Results

Prevotella intermedia was overrepresented in adenocarcinomas compared with paired adenomatous polyps. Furthermore, co-abundance of P. intermedia and F. nucleatum was observed in tumor tissues. More notably, the coexistence of these two bacteria in adenocarcinomas was associated with lymph node involvement and distant metastasis. These two bacteria also exerted additive effects on the enhancement of the migration and invasion abilities of CRC cells. Finally, conditioned media from P. intermedia promoted the migration and invasion of CRC cells.

Conclusion

This report is the first to demonstrate that P. intermedia is enriched in colorectal adenocarcinoma tissues and enhances the migration and invasion abilities of CRC cells. Moreover, P. intermedia and F. nucleatum exert additive effects on the malignant transformation of colorectal adenomas into carcinomas. These findings can be used to identify patients at a high risk of malignant transformation of colorectal adenomas or metastasis of CRC, and they can accordingly be provided optimal clinical management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12929-022-00869-0.

Acetate Promotes a Differential Energy Metabolic Response in Human HCT 116 and COLO 205 Colon Cancer Cells Impacting Cancer Cell Growth and Invasiveness

Under dysbiosis, a gut metabolic disorder, short-chain carboxylic acids (SCCAs) are secreted to the lumen, affecting colorectal cancer (CRC) development. Butyrate and propionate act as CRC growth inhibitors, but they might also serve as carbon source. In turn, the roles of acetate as metabolic fuel and protein acetylation promoter have not been clearly elucidated. To assess whether acetate favors CRC growth through active mitochondrial catabolism, a systematic study evaluating acetate thiokinase (AcK), energy metabolism, cell proliferation, and invasiveness was performed in two CRC cell lines incubated with physiological SCCAs concentrations. In COLO 205, acetate (+glucose) increased the cell density (50%), mitochondrial protein content (3–10 times), 2-OGDH acetylation, and oxidative phosphorylation (OxPhos) flux (36%), whereas glycolysis remained unchanged vs. glucose-cultured cells; the acetate-induced OxPhos activation correlated with a high AcK activity, content, and acetylation (1.5–6-fold). In contrast, acetate showed no effect on HCT116 cell growth, OxPhos, AcK activity, protein content, and acetylation. However, a substantial increment in the HIF-1α content, HIF-1α-glycolytic protein targets (1–2.3 times), and glycolytic flux (64%) was observed. Butyrate and propionate decreased the growth of both CRC cells by impairing OxPhos flux through mitophagy and mitochondrial fragmentation activation. It is described, for the first time, the role of acetate as metabolic fuel for ATP supply in CRC COLO 205 cells to sustain proliferation, aside from its well-known role as protein epigenetic regulator. The level of AcK determined in COLO 205 cells was similar to that found in human CRC biopsies, showing its potential role as metabolic marker.

Physiological Role of Glutamate Dehydrogenase in Cancer Cells

NH 4 + increased growth rates and final densities of several human metastatic cancer cells. To assess whether glutamate dehydrogenase (GDH) in cancer cells may catalyze the reverse reaction of NH 4 + fixation, its covalent regulation and kinetic parameters were determined under near-physiological conditions. Increased total protein and phosphorylation were attained in NH 4 + -supplemented metastatic cells, but total cell GDH activity was unchanged. Higher V _max values for the GDH reverse reaction vs. forward reaction in both isolated hepatoma (HepM) and liver mitochondria [rat liver mitochondria (RLM)] favored an NH 4 + -fixing role. GDH sigmoidal kinetics with NH 4 + , ADP, and leucine fitted to Hill equation showed n _H values of 2 to 3. However, the K _0.5 values for NH 4 + were over 20 mM, questioning the physiological relevance of the GDH reverse reaction, because intracellular NH 4 + in tumors is 1 to 5 mM. In contrast, data fitting to the Monod-Wyman-Changeux (MWC) model revealed lower K _m values for NH 4 + , of 6 to 12 mM. In silico analysis made with MWC equation, and using physiological concentrations of substrates and modulators, predicted GDH N-fixing activity in cancer cells. Therefore, together with its thermodynamic feasibility, GDH may reach rates for its reverse, NH 4 + -fixing reaction that are compatible with an anabolic role for supporting growth of cancer cells.

FruBPase II and ADP-PFK1 are involved in the modulation of carbon flow in the metabolism of carbohydrates in Methanosarcina acetivorans

To enhance our understanding of the control of archaeal carbon central metabolism, a detailed analysis of the regulation mechanisms of both fructose1,6-bisphosphatase (FruBPase) and ADP-phosphofructokinase-1 (ADP-PFK1) was carried out in the methanogen Methanosarcina acetivorans. No correlations were found among the transcript levels of the MA_1152 and MA_3563 (frubpase type II and pfk1) genes, the FruBPase and ADP-PFK1 activities, and their protein contents. The kinetics of the recombinant FruBPase II and ADP-PFK1 were hyperbolic and showed simple mixed-type inhibition by AMP and ATP, respectively. Under physiological metabolite concentrations, the FruBPase II and ADP-PFK1 activities were strongly modulated by their inhibitors. To assess whether these enzymes were also regulated by a phosphorylation/dephosphorylation process, the recombinant enzymes and cytosolic-enriched fractions were incubated in the presence of commercial protein phosphatase or protein kinase. De-phosphorylation of ADP-PFK1 slightly decreased its activity (i.e. Vmax) and did not change its kinetic parameters and oligomeric state. Thus, the data indicated a predominant metabolic regulation of both FruBPase and ADP-PFK1 activities by adenine nucleotides and suggested high degrees of control on the respective pathway fluxes.

Non-canonical roles for metabolic enzymes and intermediates in malignant progression and metastasis

Metabolic alterations are established as a hallmark of cancer. Such hallmark changes in cancer metabolism are characterized by reprogramming of energy-producing pathways and increases in the generation of biosynthetic intermediates to meet the needs of rapidly proliferating tumor cells. Various metabolic phenotypes such as aerobic glycolysis, increased glutamine consumption, and lipolysis have also been associated with the process of metastasis. However, in addition to the energy and biosynthetic alterations, a number of secondary functions of enzymes and metabolites are emerging that specifically contribute to metastasis. Here, we describe atypical intracellular roles of metabolic enzymes, extracellular functions of metabolic enzymes, roles of metabolites as signaling molecules, and epigenetic regulation mediated by altered metabolism, all of which can affect metastatic progression. We highlight how some of these mechanisms are already being exploited for therapeutic purposes, and discuss how others show similar potential.

Heart myxoma develops oncogenic and metastatic phenotype

PURPOSE

Heart myxomas have been frequently considered as benign lesions associated with Carney's complex. However, after surgical removal, myxomas re-emerge causing dysfunctional heart.

METHODS

To identify whether cardiac myxomas may develop a metastatic phenotype as occurs in malignant cancers, a profile of several proteins involved in malignancy such as oncogenes (c-MYC, K-RAS and H-RAS), cancer-associated metabolic transcriptional factors (HIF-1α, p53 and PPAR-γ) and epithelial-mesenchymal transition proteins (fibronectin, vimentin, β-catenin, SNAIL and MMP-9) were evaluated in seven samples from a cohort of patients with atrial and ventricular myxomas. The analysis was also performed in: (1) cardiac tissue surrounding the area where myxoma was removed; (2) non-cancer heart tissue (NCHT); and (3) malignant triple negative breast cancer biopsies for comparative purposes.

RESULTS

Statistical analysis applying univariate (Kruskal-Wallis and Dunn's tests) and multivariate analyses (PCA, principal component analysis) revealed that heart myxomas (7-15 times) and myxoma surrounding tissue (22-99 times) vs. NCHT showed high content of c-MYC, p53, vimentin, and HIF-1α, indicating that both myxoma and its surrounding area express oncogenes and malignancy-related proteins as occurs in triple negative breast cancer.

CONCLUSIONS

Based on ROC (receiver operating characteristics) statistical analysis, c-MYC, HIF-1α, p53, and vimentin may be considered potential biomarkers for malignancy detection in myxoma.

Up-regulation of Key Glycolysis Proteins in Cancer Development

In rapid proliferating cancer cells, there is a need for fast ATP and lactate production, therefore cancer cells turn off oxidative phosphorylation and turn on the so called "Warburg effect". This regulating the expression of genes involved in glycolysis. According to many studies, glucose transporter 1, which supplies glucose to the cell, is the most abundantly expressed transporter in cancer cells. Hexokinase 2, is one of four hexokinase isoenzymes, is also another highly expressed enzyme in cancer cells and it functions to enhance the glycolytic rate. The up-regulation of these two proteins has been established as an important factor in promoting development and metastasis in many types of cancer. Furthermore, other enzymes involved in glycolysis pathway such as phosphoglucose isomerase and glyceraldehyde 3-phosphate dehydrogenase, exhibit additional functions in promoting tumor growth in a non-glycolytic way. This review demonstrates the pivotal role of GLUT1, HK2, PGI and GAPDH in cancer development. In particular, we look at how the multifunctional proteins, PGI and GAPDH, affect cancer cell survival. We also present various clinical cancer cases in terms of the overexpression of selected proteins, which may be considered as a therapeutic target.

Control of the NADPH supply and GSH recycling for oxidative stress management in hepatoma and liver mitochondria

To unveil what controls mitochondrial ROS detoxification, the NADPH supply and GSH/GSSG recycling for oxidative stress management were analyzed in cancer and non-cancer mitochondria. Therefore, proteomic and kinetomic analyses were carried out of the mitochondrial (i) NADPH producing and (ii) GSH/GSSG recycling enzymes associated to oxidative stress management. The protein contents of the eight enzymes analyzed were similar or even higher in AS-30D rat hepatoma mitochondria (HepM) than in rat liver (RLM) and rat heart (RHM) mitochondria, suggesting that the NADPH/GSH/ROS pathway was fully functional in cancer mitochondria. The Vmax values of IDH-2 were much greater than those of GDH, TH and ME, suggesting that IDH-2 is the predominant NADPH producer in the three mitochondrial types; in fact, the GDH reverse reaction was favored. The Vmax values of GR and GPx were lower in HepM than in RLM, suggesting that the oxidative stress management is compromised in cancer mitochondria. The Km values of IDH-2, GR and GPx were all similar among the different mitochondrial types. Kinetic modeling revealed that the oxidative stress management was mainly controlled by GR, GPx and IDH. Modeling and experimentation also revealed that, due to their higher IDH-2 activity and lower GPx activity presumably by acetylation, HepM (i) showed higher steady-state NADPH levels; (ii) required greater peroxide concentrations to achieve reliable steady-state fluxes and metabolite concentration; and (iii) endured higher peroxide concentrations without collapsing their GSH/GSSG ratios. Then, to specifically prompt lower GSH/GSSG ratios under oxidative stress thus compromising cancer mitochondria functioning, GPx should be re-activated.

Comprehensive single-cell transcriptome analysis reveals heterogeneity in endometrioid adenocarcinoma tissues

Single cell transcriptome analysis of a cancer tissue can provide objective assessment of subtype population or the activation of each of various microenvironment component cells. In this study, we applied our newly developed technique of single cell analysis to the myometrial infiltration side (M-side) and the endometrial side (E-side) of a human endometrioid adenocarcinoma with squamous differentiation tissues. We also analyzed spherogenic cultures derived from the same tissue to identify putative regulators of stemness in vivo. Cancer cells in the E-side were highly malignant compared with those in the M-side. Many cells on the E-side were positive for spheroid-specific tumorigenesis-related markers including SOX2. In addition, there were higher numbers of epithelial-to-mesenchymal transition (EMT) cells in the E-side compared with the M-side. This study identified a site containing cells with high malignant potential such as EMT and cancer stem-like cells in cancer tissues. Finally, we demonstrate that established endometrioid adenocarcinoma subtype classifiers were variably expressed across individual cells within a tumor. Thus, such intratumoral heterogeneity may be related to prognostic implications.

Hypoglycemia Enhances Epithelial-Mesenchymal Transition and Invasiveness, and Restrains the Warburg Phenotype, in Hypoxic HeLa Cell Cultures and Microspheroids

The accelerated growth of solid tumors leads to episodes of both hypoxia and hypoglycemia (HH) affecting their intermediary metabolism, signal transduction, and transcriptional activity. A previous study showed that normoxia (20% O₂ ) plus 24 h hypoglycemia (2.5 mM glucose) increased glycolytic flux whereas oxidative phosphorylation (OxPhos) was unchanged versus normoglycemia in HeLa cells. However, the simultaneous effect of HH on energy metabolism has not been yet examined. Therefore, the effect of hypoxia (0.1-1% O₂ ) plus hypoglycemia on the energy metabolism of HeLa cells was analyzed by evaluating protein content and activity, along with fluxes of both glycolysis and OxPhos. Under hypoxia, in which cell growth ceased and OxPhos enzyme activities, ΔΨm and flux were depressed, hypoglycemia did not stimulate glycolytic flux despite increasing H-RAS, p-AMPK, GLUT1, GLUT3, and HKI levels, and further decreasing mitochondrial enzyme content. The impaired mitochondrial function in HH cells correlated with mitophagy activation. The depressed OxPhos and unchanged glycolysis pattern was also observed in quiescent cells from mature multicellular tumor spheroids, suggesting that these inner cell layers are similarly subjected to HH. The principal ATP supplier was glycolysis for HH 2D monolayer and 3D quiescent spheroid cells. Accordingly, the glycolytic inhibitors iodoacetate and gossypol were more effective than mitochondrial inhibitors in decreasing HH-cancer cell viability. Under HH, stem cell-, angiogenic-, and EMT-biomarkers, as well as glycoprotein-P content and invasiveness, were also enhanced. These observations indicate that HH cancer cells develop an attenuated Warburg and pronounced EMT- and invasive-phenotype. J. Cell. Physiol. 232: 1346-1359, 2017. © 2016 Wiley Periodicals, Inc.

Assessment of the low inhibitory specificity of oxamate, aminooxyacetate and dichloroacetate on cancer energy metabolism

BACKGROUND

Exceedingly high therapeutic/experimental doses of metabolic drugs such as oxamate, aminooxyacetate (AOA) and dichloroacetate (DCA) are required to diminish growth, glycolysis and oxidative phosphorylation (OxPhos) of different cancer cells. To identify the mechanisms of action of these drugs on cancer energy metabolism, a systematic analysis of their specificities was undertaken.

METHODS

Hepatocarcinoma AS-30D cells were treated with the inhibitors and glycolysis and OxPhos enzyme activities, metabolites and fluxes were analyzed. Kinetic modeling of glycolysis was used to identify the regulatory mechanisms.

RESULTS

Oxamate (i) not only inhibited LDH, but also PYK and ENO activities inducing an increase in the cytosolic NAD(P)H, Fru1,6BP and DHAP levels in AS-30D cells; (ii) it slightly inhibited HPI, ALD and Glc6PDH; and (iii) it inhibited pyruvate-driven OxPhos in isolated heart mitochondria. AOA (i) strongly inhibited both AAT and AlaT, and 2-OGDH and glutamate-driven OxPhos; and (ii) moderately affected GAPDH and TPI. DCA slightly affected pyruvate-driven OxPhos and Glc6PDH. Kinetic modeling of cancer glycolysis revealed that oxamate inhibition of LDH, PYK and ENO was insufficient to achieve glycolysis flux inhibition. To do so, HK, HPI, TPI and GAPDH have to be also inhibited by the accumulated Fru1,6BP and DHAP induced by oxamate.

CONCLUSION

Oxamate, AOA, and DCA are not specific drugs since they inhibit several enzymes/transporters of the glycolytic and OxPhos pathways through direct interaction or indirect mechanisms.

GENERAL SIGNIFICANCE

These data explain why oxamate or AOA, through their multisite inhibitory actions on glycolysis or OxPhos, may be able to decrease the proliferation of cancer cells.

Epithelial-mesenchymal transition: a new target in anticancer drug discovery

The conversion of cells with an epithelial phenotype into cells with a mesenchymal phenotype, referred to as epithelial-mesenchymal transition, is a critical process for embryonic development that also occurs in adult life, particularly during tumour progression. Tumour cells undergoing epithelial-mesenchymal transition acquire the capacity to disarm the body's antitumour defences, resist apoptosis and anticancer drugs, disseminate throughout the organism, and act as a reservoir that replenishes and expands the tumour cell population. Epithelial-mesenchymal transition is therefore becoming a target of prime interest for anticancer therapy. Here, we discuss the screening and classification of compounds that affect epithelial-mesenchymal transition, highlight some compounds of particular interest, and address issues related to their clinical application.

Increased Expression of the Autocrine Motility Factor is Associated With Poor Prognosis in Patients With Clear Cell-Renal Cell Carcinoma

Glucose-6-phosphate isomerase (GPI), also known as phosphoglucose isomerase, was initially identified as the second glycolytic enzyme that catalyzes the interconversion of glucose-6-phosphate to fructose-6-phosphate. Later studies demonstrated that GPI was the same as the autocrine motility factor (AMF), and that it mediates its biological effects through the interaction with its surface receptor (AMFR/gp78). In this study, we assessed the role of GPI/AMF as a prognostic factor for clear cell renal cell carcinoma (ccRCC) cancer-specific (CSS) and progression-free survival (PFS). In addition, we evaluated the expression and localization of GPI/AMF and AMFR, using tissue microarray-based immunohistochemistry (TMA-IHC), indirect immunofluorescence (IF), and confocal microscopy analysis.Primary renal tumor and nonneoplastic tissues were collected from 180 patients who underwent nephrectomy for ccRCC. TMA-IHC and IF staining showed an increased signal for both GPI and AMFR in cancer cells, and their colocalization on plasma membrane. Kaplan-Meier curves showed significant differences in CSS and PFS among groups of patients with high versus low GPI expression. In particular, patients with high tissue levels of GPI had a 5-year survival rate of 58.8%, as compared to 92.1% for subjects with low levels (P < 0.0001). Similar findings were observed for PFS (56.8% vs 93.3% at 5 years). At multivariate analysis, GPI was an independent adverse prognostic factor for CSS (HR = 1.26; P = 0.001), and PFS (HR = 1.16; P = 0.01).In conclusion, our data suggest that GPI could serve as a marker of ccRCC aggressiveness and a prognostic factor for CSS and PFS.

Co-culture of 3D tumor spheroids with fibroblasts as a model for epithelial-mesenchymal transition in vitro

Epithelial-mesenchymal transition (EMT) acts as a facilitator of metastatic dissemination in the invasive margin of malignant tumors where active tumor-stromal crosstalks take place. Co-cultures of cancer cells with cancer-associated fibroblasts (CAFs) are often used as in vitro models of EMT. We established a tumor-fibroblast proximity co-culture using HT-29 tumor spheroids (TSs) with CCD-18 co fibroblasts. When co-cultured with TSs, CCD-18 co appeared activated, and proliferative activity as well as cell migration increased. Expression of fibronectin increased whereas laminin and type I collagen decreased in TSs co-cultured with fibroblasts compared to TSs alone, closely resembling the margin of in vivo xenograft tissue. Active TGFβ1 in culture media significantly increased in TS co-cultures but not in 2D co-cultures of cancer cells-fibroblasts, indicating that 3D context-associated factors from TSs may be crucial to crosstalks between cancer cells and fibroblasts. We also observed in TSs co-cultured with fibroblasts increased expression of α-SMA, EGFR and CTGF; reduced expression of membranous β-catenin and E-cadherin, together suggesting an EMT-like changes similar to a marginal region of xenograft tissue in vivo. Overall, our in vitro TS-fibroblast proximity co-culture mimics the EMT-state of the invasive margin of in vivo tumors in early metastasis.

Glucose-6-phosphate isomerase promotes the proliferation and inhibits the apoptosis in fibroblast-like synoviocytes in rheumatoid arthritis

Introduction

Fibroblast-like synoviocytes (FLS) play an important role in the pathogenesis of rheumatoid arthritis (RA). This study aimed to investigate the role of glucose 6-phosphate isomerase (GPI) in the proliferation of RA-FLS.

Methods

The distribution of GPI in synovial tissues from RA and osteoarthritis (OA) patients was examined by immunohistochemical analysis. FLS were isolated and cultured, cellular GPI level was detected by real-time polymerase chain reaction (PCR) and Western blot analysis, and secreted GPI was detected by Western blot and enzyme-linked immunosorbent assay (ELISA). Doxorubicin (Adriamycin, ADR) was used to induce apoptosis. Cell proliferation was determined by MTS assay. Flow cytometry was used to detect cell cycle and apoptosis. Secreted pro-inflammatory cytokines were measured by ELISA.

Results

GPI was abundant in RA-FLS and was an autocrine factor of FLS. The proliferation of both RA and OA FLS was increased after GPI overexpression, but was decreased after GPI knockdown. Meanwhile, exogenous GPI stimulated, while GPI antibody inhibited, FLS proliferation. GPI positively regulated its receptor glycoprotein 78 and promoted G1/S phase transition via extracellular regulated protein kinases activation and Cyclin D1 upregulation. GPI inhibited ADR-induced apoptosis accompanied by decreased Fas and increased Survivin in RA FLS. Furthermore, GPI increased the secretion of tumor necrosis factor-α and interleukin-1β by FLS.

Conclusions

GPI plays a pathophysiologic role in RA by stimulating the proliferation, inhibiting the apoptosis, and increasing pro-inflammatory cytokine secretion of FLS.

Changes in protein expression in two cholangiocarcinoma cell lines undergoing formation of multicellular tumor spheroids in vitro

Epithelial-to-Mesenchymal Transition (EMT) is relevant in malignant growth and frequently correlates with worsening disease progression due to its implications in metastases and resistance to therapeutic interventions. Although EMT is known to occur in several types of solid tumors, the information concerning tumors arising from the epithelia of the bile tract is still limited. In order to approach the problem of EMT in cholangiocarcinoma, we decided to investigate the changes in protein expression occurring in two cell lines under conditions leading to growth as adherent monolayers or to formation of multicellular tumor spheroids (MCTS), which are considered culture models that better mimic the growth characteristics of in-vivo solid tumors. In our system, changes in phenotypes occur with only a decrease in transmembrane E-cadherin and vimentin expression, minor changes in the transglutaminase protein/activity but with significant differences in the proteome profiles, with declining and increasing expression in 6 and in 16 proteins identified by mass spectrometry. The arising protein patterns were analyzed based on canonical pathways and network analysis. These results suggest that significant metabolic rearrangements occur during the conversion of cholangiocarcinomas cells to the MCTS phenotype, which most likely affect the carbohydrate metabolism, protein folding, cytoskeletal activity, and tissue sensitivity to oxygen.

Canonical and new generation anticancer drugs also target energy metabolism

Significant efforts have been made for the development of new anticancer drugs (protein kinase or proteasome inhibitors, monoclonal humanized antibodies) with presumably low or negligible side effects and high specificity. However, an in-depth analysis of the side effects of several currently used canonical (platin-based drugs, taxanes, anthracyclines, etoposides, antimetabolites) and new generation anticancer drugs as the first line of clinical treatment reveals significant perturbation of glycolysis and oxidative phosphorylation. Canonical and new generation drug side effects include decreased (1) intracellular ATP levels, (2) glycolytic/mitochondrial enzyme/transporter activities and/or (3) mitochondrial electrical membrane potentials. Furthermore, the anti-proliferative effects of these drugs are markedly attenuated in tumor rho (0) cells, in which functional mitochondria are absent; in addition, several anticancer drugs directly interact with isolated mitochondria affecting their functions. Therefore, several anticancer drugs also target the energy metabolism, and hence, the documented inhibitory effect of anticancer drugs on cancer growth should also be linked to the blocking of ATP supply pathways. These often overlooked effects of canonical and new generation anticancer drugs emphasize the role of energy metabolism in maintaining cancer cells viable and its targeting as a complementary and successful strategy for cancer treatment.