Advances in glucose metabolism research in colorectal cancer

Targeting the Warburg effect: A revisited perspective from molecular mechanisms to traditional and innovative therapeutic strategies in cancer

Cancer reprogramming is an important facilitator of cancer development and survival, with tumor cells exhibiting a preference for aerobic glycolysis beyond oxidative phosphorylation, even under sufficient oxygen supply condition. This metabolic alteration, known as the Warburg effect, serves as a significant indicator of malignant tumor transformation. The Warburg effect primarily impacts cancer occurrence by influencing the aerobic glycolysis pathway in cancer cells. Key enzymes involved in this process include glucose transporters (GLUTs), HKs, PFKs, LDHs, and PKM2. Moreover, the expression of transcriptional regulatory factors and proteins, such as FOXM1, p53, NF-κB, HIF1α, and c-Myc, can also influence cancer progression. Furthermore, lncRNAs, miRNAs, and circular RNAs play a vital role in directly regulating the Warburg effect. Additionally, gene mutations, tumor microenvironment remodeling, and immune system interactions are closely associated with the Warburg effect. Notably, the development of drugs targeting the Warburg effect has exhibited promising potential in tumor treatment. This comprehensive review presents novel directions and approaches for the early diagnosis and treatment of cancer patients by conducting in-depth research and summarizing the bright prospects of targeting the Warburg effect in cancer.

Decoding the regulatory landscape of lncRNAs as potential diagnostic and prognostic biomarkers for gastric and colorectal cancers

Colorectal cancer (CRC) and gastric cancer (GC) are major contributors to cancer-related mortality worldwide. Despite advancements in understanding molecular mechanisms and improved drug treatments, the overall survival rate for patients remains unsatisfactory. Metastasis and drug resistance are major challenges contributing to the high mortality rate in both CRC and GC. Recent research has shed light on the role of long noncoding RNAs (lncRNAs) in the development and progression of these cancers. LncRNAs regulate gene expression through various mechanisms, including epigenetic modifications and interactions with microRNAs (miRNAs) and proteins. They can serve as miRNA precursors or pseudogenes, modulating gene expression at transcriptional and post-transcriptional levels. Additionally, circulating lncRNAs have emerged as non-invasive biomarkers for the diagnosis, prognosis, and prediction of drug therapy response in CRC and GC. This review explores the intricate relationship between lncRNAs and CRC/GC, encompassing their roles in cancer development, progression, and chemoresistance. Furthermore, it discusses the potential of lncRNAs as therapeutic targets in these malignancies. The interplay between lncRNAs, miRNAs, and tumor microenvironment is also highlighted, emphasizing their impact on the complexity of cancer biology. Understanding the regulatory landscape and molecular mechanisms governed by lncRNAs in CRC and GC is crucial for the development of effective diagnostic and prognostic biomarkers, as well as novel therapeutic strategies. This review provides a comprehensive overview of the current knowledge and paves the way for further exploration of lncRNAs as key players in the management of CRC and GC.

Uncovering novel therapeutic targets in glucose, nucleotides and lipids metabolism during cancer and neurological diseases

BACKGROUND

Cell metabolism functions without a stop in normal and pathological cells. Different metabolic changes occur in the disease. Cell metabolism influences biochemical and metabolic processes, signaling pathways, and gene regulation. Knowledge regarding disease metabolism is limited.

OBJECTIVE

The review examines the cell metabolism of glucose, nucleotides, and lipids during homeostatic and pathological conditions of neurotoxicity, neuroimmunological disease, Parkinson's disease, thymoma in myasthenia gravis, and colorectal cancer.

METHODS

Data collection includes electronic databases, the National Center for Biotechnology Information, and Google Scholar, with several inclusion criteria: cell metabolism, glucose metabolism, nucleotide metabolism, and lipid metabolism in health and disease patients suffering from neurotoxicity, neuroinflammation, Parkinson's disease, thymoma in myasthenia gravis. The initial number of collected and analyzed papers is 250. The final analysis included 150 studies out of 94 selected papers. After the selection process, 62.67% remains useful.

RESULTS AND CONCLUSION

A literature search shows that signaling molecules are involved in metabolic changes in cells. Differences between cancer and neuroimmunological diseases are present in the result section. Our finding enables insight into novel therapeutic targets and the development of scientific approaches for cancer and neurological disease onset, outcome, progression, and treatment, highlighting the importance of metabolic dysregulation. Current understanding, emerging research technologies and potential therapeutic interventions in metabolic programming is disucussed and highlighted.

CDK6: an attractive therapeutic target for T-ALL/LBL

INTRODUCTION

Human T-cell acute lymphoblastic leukemia/T-cell lymphoblastic lymphoma (T-ALL/LBL) is a type of cancer that originates from the bone marrow and spreads quickly to other organs. Long-term survival rate with current available chemotherapy is less than 20%. Despite the potentially huge market, a truly effective and safe therapy for T-ALL/LBL is elusive. Thus, it is imperative to identify new therapeutic ways to target essential pathways in T-ALL that regulate the proliferation and survival of these cancer cells.

AREAS COVERED

The role of the Cyclin-dependent kinase 6 (CDK6) pathway in human T-ALL is of significant interest with major clinical/translational relevance. This review covers the recent advances in elucidating the essential roles of CDK6 and its closely regulated networks in proliferation, survival, and metabolism of T-ALL cells, with new insight into its mechanisms of action which hopefully could trigger the identification of new therapeutic avenues.

EXPERT OPINION

Animal models showed that inhibition of CDK6 and its related networks blocked initiation, growth, and survival of T-ALL in vivo. Numerous clinical trials of CDK4/6 inhibitors are ongoing in T-ALL. Specific CDK6 inhibitors alone or novel combination regimens may hopefully delay the progression, or even reverse the symptoms of T-ALL, leading to disease eradication and cure.

Vinpocetine mitigates DMH-induce pre-neoplastic colon damage in rats through inhibition of pro-inflammatory cytokines

Colorectal cancer (CRC) is currently recognized as the third most prevalent cancer worldwide. Vinpocetine is a synthetic derivative of the vinca alkaloid vincamine. It has been found effective in ameliorating the growth and progression of cancerous cells. However, its pharmacological effect on colon damage remains elusive. Hence, in this study, we have shown the role of vinpocetine in DMH-induced colon carcinogenesis. At first, male albino Wistar rats were administered with DMH consistently for four weeks to induce pre-neoplastic colon damage. Afterward, animals were treated with vinpocetine (4.2 and 8.4 mg/kg/day p.o.) for 15 days. Serum samples were collected to assess the physiological parameters, including ELISA and NMR metabolomics. Colon from all the groups was collected and processed separately for histopathology and western blot analysis. Vinpocetine attenuated the altered plasma parameters; lipid profile and showed anti-proliferative action as evidenced by suppressed COX-2 stimulation and decreased levels of IL-1β, IL-2, IL-6, and IL-10. Vinpocetine is significantly effective in preventing CRC which may be associated with its anti-inflammatory and antioxidant potential. Accordingly, vinpocetine could serve as a potential anticancer agent for CRC treatment and thus be considered for future clinical and therapeutic research.

Proteome profiling of endogenous and potential S-nitrosylation in colorectal cancer

Background

As a common cancer with high incidence rate and mortality, colorectal cancer (CRC) is seriously threatening human health. S-nitrosylation (SNO) proteins mediated by nitric oxide (NO) has important implications in the genesis, progression, and apoptosis of CRC. It's worth noting that the SNO proteins also play an important role in the tumor endocrine and metabolic pathways of CRC.

Materials and methods

In this study, the protein extracts of human tissues and cell lines were treated by biotin switch technology and magnetic beads enrichment. The proteomic results of endogenous and potential SNO proteins were analyzed by mass spectrometry (MS). Through the comparison and analysis of MS results, Gene Ontology (GO) analysis, and literatures, some endogenous and potential SNO proteins were identified in CRC, which were closely related to the tumor endocrine and metabolic pathways, the apoptotic signaling pathways, protein maturation, and other biological processes of the proliferation and apoptosis of CRC cells.

Results

A total of 19 proteins containing potential or endogenous SNO sites were detected in both human cancer tissue and SW 480 cells. Through the cross validation of MS results, GO analysis, and literatures, several SNO proteins were identified frequently in CRC, such as the actin, cytoplasmic 1 (ACTB), peroxiredoxin-4 (PRDX4), protein S100A8 (S100A8), pyruvate kinase PKM (PKM), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), which were closely related to the tumor endocrine and metabolic pathways and the apoptotic signaling pathways of CRC.

Conclusion

Different CRC cells and tissues contained potential and endogenous SNO modified proteins. In addition, some SNO proteins could participate in the proliferation, metastasis and apoptosis of CRC by regulating the tumor endocrine and metabolic pathways.

Targeting cancer-specific metabolic pathways for developing novel cancer therapeutics

Cancer is a heterogeneous disease characterized by various genetic and phenotypic aberrations. Cancer cells undergo genetic modifications that promote their proliferation, survival, and dissemination as the disease progresses. The unabated proliferation of cancer cells incurs an enormous energy demand that is supplied by metabolic reprogramming. Cancer cells undergo metabolic alterations to provide for increased energy and metabolite requirement; these alterations also help drive the tumor progression. Dysregulation in glucose uptake and increased lactate production via "aerobic glycolysis" were described more than 100 years ago, and since then, the metabolic signature of various cancers has been extensively studied. However, the extensive research in this field has failed to translate into significant therapeutic intervention, except for treating childhood-ALL with amino acid metabolism inhibitor L-asparaginase. Despite the growing understanding of novel metabolic alterations in tumors, the therapeutic targeting of these tumor-specific dysregulations has largely been ineffective in clinical trials. This chapter discusses the major pathways involved in the metabolism of glucose, amino acids, and lipids and highlights the inter-twined nature of metabolic aberrations that promote tumorigenesis in different types of cancer. Finally, we summarise the therapeutic interventions which can be used as a combinational therapy to target metabolic dysregulations that are unique or common in blood, breast, colorectal, lung, and prostate cancer.

Enhancing an Oxidative "Trojan Horse" Action of Vitamin C with Arsenic Trioxide for Effective Suppression of KRAS-Mutant Cancers: A Promising Path at the Bedside

The turn-on mutations of the KRAS gene, coding a small GTPase coupling growth factor signaling, are contributing to nearly 25% of all human cancers, leading to highly malignant tumors with poor outcomes. Targeting of oncogenic KRAS remains a most challenging task in oncology. Recently, the specific G12C mutant KRAS inhibitors have been developed but with a limited clinical outcome because they acquire drug resistance. Alternatively, exploiting a metabolic breach of KRAS-mutant cancer cells related to a glucose-dependent sensitivity to oxidative stress is becoming a promising indirect cancer targeting approach. Here, we discuss the use of a vitamin C (VC) acting in high dose as an oxidative "Trojan horse" agent for KRAS-mutant cancer cells that can be potentiated with another oxidizing drug arsenic trioxide (ATO) to obtain a potent and selective cytotoxic impact. Moreover, we outline the advantages of VC's non-natural enantiomer, D-VC, because of its distinctive pharmacokinetics and lower toxicity. Thus, the D-VC and ATO combination shows a promising path to treat KRAS-mutant cancers in clinical settings.

Alterations in Gene Pair Correlations as Potential Diagnostic Markers for Colon Cancer

Colorectal cancer (CRC) is a leading cause of death from cancer in Canada. Early detection of CRC remains crucial in managing disease prognosis and improving patient survival. It can also facilitate prevention, screening, and treatment before the disease progresses to a chronic stage. In this study, we developed a strategy for identifying colon cancer biomarkers from both gene expression and gene pair correlation. Using the RNA-Seq dataset TCGA-COAD, a panel of 71 genes, including the 20 most upregulated genes, 20 most downregulated genes and 31 genes involved in the most significantly altered gene pairs, were selected as potential biomarkers for colon cancer. This signature set of genes could be used for early diagnosis. Furthermore, this strategy could be applied to other types of cancer.

Identification and validation of a metabolism-related gene signature for the prognosis of colorectal cancer: a multicenter cohort study

OBJECTIVE

Cell metabolism plays a vital role in the proliferation, metastasis and sensitivity to chemotherapy drugs of colorectal cancer. The purpose of this multicenter cohort study is to investigate the potential genes indicating clinical outcomes in colorectal cancer patients.

METHODS

We analyzed gene expression profiles of colorectal cancer to identify differentially expressed genes then used these differentially expressed genes to construct prognostic signature based on the least absolute shrink-age and selection operator Cox regression model. In addition, the multi-gene signature was validated in independent datasets including our multicenter cohort. Finally, nomograms were set up to evaluate the prognosis of colorectal cancer patients.

RESULTS

Seventeen metabolism-related genes were determined in the least absolute shrink-age and selection operator model to construct signature, with area under receiver operating characteristic curve for relapse-free survival, 0.741, 0.755 and 0.732 at 1, 3 and 5 year, respectively. External validation datasets, GSE14333, GSE37892, GSE17538 and the Cancer Genome Atlas cohorts, were analyzed and stratified, indicating that the metabolism-related signature was reliable in discriminating high- and low-risk colorectal cancer patients. Area under receiver operating characteristic curves for relapse-free survival in our multicenter validation cohort were 0.801, 0.819 and 0.857 at 1, 3 and 5 year, respectively. Nomograms incorporating the genetic biomarkers and clinical pathological features were set up, which yielded good discrimination and calibration in the prediction of prognosis for colorectal cancer patients.

CONCLUSION

An original metabolism-related signature was developed as a predictive model for the prognosis of colorectal cancer patients. A nomogram based on the signature was advantageous to facilitate personalized counselling and treatment of colorectal cancer patients.

Interplay between Epigenetics and Cellular Metabolism in Colorectal Cancer

Cellular metabolism alterations have been recognized as one of the most predominant hallmarks of colorectal cancers (CRCs). It is precisely regulated by many oncogenic signaling pathways in all kinds of regulatory levels, including transcriptional, post-transcriptional, translational and post-translational levels. Among these regulatory factors, epigenetics play an essential role in the modulation of cellular metabolism. On the one hand, epigenetics can regulate cellular metabolism via directly controlling the transcription of genes encoding metabolic enzymes of transporters. On the other hand, epigenetics can regulate major transcriptional factors and signaling pathways that control the transcription of genes encoding metabolic enzymes or transporters, or affecting the translation, activation, stabilization, or translocation of metabolic enzymes or transporters. Interestingly, epigenetics can also be controlled by cellular metabolism. Metabolites not only directly influence epigenetic processes, but also affect the activity of epigenetic enzymes. Actually, both cellular metabolism pathways and epigenetic processes are controlled by enzymes. They are highly intertwined and are essential for oncogenesis and tumor development of CRCs. Therefore, they are potential therapeutic targets for the treatment of CRCs. In recent years, both epigenetic and metabolism inhibitors are studied for clinical use to treat CRCs. In this review, we depict the interplay between epigenetics and cellular metabolism in CRCs and summarize the underlying molecular mechanisms and their potential applications for clinical therapy.

Genetic Mutations and Non-Coding RNA-Based Epigenetic Alterations Mediating the Warburg Effect in Colorectal Carcinogenesis

Colorectal cancer (CRC) development is a gradual process defined by the accumulation of numerous genetic mutations and epigenetic alterations leading to the adenoma-carcinoma sequence. Despite significant advances in the diagnosis and treatment of CRC, it continues to be a leading cause of cancer-related deaths worldwide. Even in the presence of oxygen, CRC cells bypass oxidative phosphorylation to produce metabolites that enable them to proliferate and survive-a phenomenon known as the "Warburg effect". Understanding the complex glucose metabolism in CRC cells may support the development of new diagnostic and therapeutic approaches. Here we discuss the most recent findings on genetic mutations and epigenetic modulations that may positively or negatively regulate the Warburg effect in CRC cells. We focus on the non-coding RNA (ncRNA)-based epigenetics, and we present a perspective on the therapeutic relevance of critical molecules and ncRNAs mediating the Warburg effect in CRC cells. All the relevant studies were identified and assessed according to the genes and enzymes mediating the Warburg effect. The findings summarized in this review should provide a better understanding of the relevance of genetic mutations and the ncRNA-based epigenetic alterations to CRC pathogenesis to help overcome chemoresistance.

Insulin-Like Growth Factor 1 (IGF-1) Signaling in Glucose Metabolism in Colorectal Cancer

Colorectal cancer (CRC) is one of the most common aggressive carcinoma types worldwide, characterized by unfavorable curative effect and poor prognosis. Epidemiological data re-vealed that CRC risk is increased in patients with metabolic syndrome (MetS) and its serum components (e.g., hyperglycemia). High glycemic index diets, which chronically raise post-prandial blood glucose, may at least in part increase colon cancer risk via the insulin/insulin-like growth factor 1 (IGF-1) signaling pathway. However, the underlying mechanisms linking IGF-1 and MetS are still poorly understood. Hyperactivated glucose uptake and aerobic glycolysis (the Warburg effect) are considered as a one of six hallmarks of cancer, including CRC. However, the role of insulin/IGF-1 signaling during the acquisition of the Warburg metabolic phenotypes by CRC cells is still poorly understood. It most likely results from the interaction of multiple processes, directly or indirectly regulated by IGF-1, such as activation of PI3K/Akt/mTORC, and Raf/MAPK signaling pathways, activation of glucose transporters (e.g., GLUT1), activation of key glycolytic enzymes (e.g., LDHA, LDH5, HK II, and PFKFB3), aberrant expression of the oncogenes (e.g., MYC, and KRAS) and/or overexpression of signaling proteins (e.g., HIF-1, TGF-β1, PI3K, ERK, Akt, and mTOR). This review describes the role of IGF-1 in glucose metabolism in physiology and colorectal carcinogenesis, including the role of the insulin/IGF system in the Warburg effect. Furthermore, current therapeutic strategies aimed at repairing impaired glucose metabolism in CRC are indicated.

Molecular subtypes of colorectal cancer: An emerging therapeutic opportunity for personalized medicine

Molecular subtypes-based therapies offer new potential framework for desired and precise outcome in clinical settings. Current treatment strategies in colorectal cancer are largely 'one drug fit all' model for patients that display same pathological conditions. However, CRC is a very heterogenous set of malignancy that does not support for above criteria. Each subtype displays different pathological and genetic signatures. Based on these features, therapeutic stratification for individual patients may be designed, which may ultimately lead to improved therapeutic outcomes. In this comprehensive review, we have attempted to briefly outline major CRC pathways. A detailed overview of molecular subtypes and their clinical significance has been discussed. Present and future methods, governing CRC subtyping in the era of personalized therapy with a special emphasis on CMS subtypes of CRC has been reviewed. Together, discovery and validation of new CRC patient stratification methods, screening for novel therapeutic targets, and enhanced diagnosis of CRC may improve the treatment outcome.

Effects of the Novel PFKFB3 Inhibitor KAN0438757 on Colorectal Cancer Cells and Its Systemic Toxicity Evaluation In Vivo

BACKGROUND

Despite substantial progress made in the last decades in colorectal cancer (CRC) research, new treatment approaches are still needed to improve patients' long-term survival. To date, the promising strategy to target tumor angiogenesis metabolically together with a sensitization of CRC to chemo- and/or radiotherapy by PFKFB3 (6-phosphofructo-2-kinase/fructose-2,6-biphosphatase-3) inhibition has never been tested. Therefore, initial evaluation and validation of newly developed compounds such as KAN0438757 and their effects on CRC cells are crucial steps preceding to in vivo preclinical studies, which in turn may consolidate new therapeutic targets.

MATERIALS AND METHODS

The efficiency of KAN0438757 to block PFKFB3 expression and translation in human CRC cells was evaluated by immunoblotting and real-time PCR. Functional in vitro assays assessed the effects of KAN0438757 on cell viability, proliferation, survival, adhesion, migration and invasion. Additionally, we evaluated the effects of KAN0438757 on matched patient-derived normal and tumor organoids and its systemic toxicity in vivo in C57BL6/N mice.

RESULTS

High PFKFB3 expression is correlated with a worse survival in CRC patients. KAN0438757 reduces PFKFB3 protein expression without affecting its transcriptional regulation. Additionally, a concentration-dependent anti-proliferative effect was observed. The migration and invasion capacity of cancer cells were significantly reduced, independent of the anti-proliferative effect. When treating colonic patient-derived organoids with KAN0438757 an impressive effect on tumor organoids growth was apparent, surprisingly sparing normal colonic organoids. No high-grade toxicity was observed in vivo.

CONCLUSION

The PFKFB3 inhibitor KAN0438757 significantly reduced CRC cell migration, invasion and survival. Moreover, on patient-derived cancer organoids KAN0438757 showed significant effects on growth, without being overly toxic in normal colon organoids and healthy mice. Our findings strongly encourage further translational studies to evaluate KAN0438757 in CRC therapy.

Hemistepsin A suppresses colorectal cancer growth through inhibiting pyruvate dehydrogenase kinase activity

Most cancer cells primarily produce their energy through a high rate of glycolysis followed by lactic acid fermentation even in the presence of abundant oxygen. Pyruvate dehydrogenase kinase (PDK) 1, an enzyme responsible for aerobic glycolysis via phosphorylating and inactivating pyruvate dehydrogenase (PDH) complex, is commonly overexpressed in tumors and recognized as a therapeutic target in colorectal cancer. Hemistepsin A (HsA) is a sesquiterpene lactone isolated from Hemistepta lyrata Bunge (Compositae). Here, we report that HsA is a PDK1 inhibitor can reduce the growth of colorectal cancer and consequent activation of mitochondrial ROS-dependent apoptotic pathway both in vivo and in vitro. Computational simulation and biochemical assays showed that HsA directly binds to the lipoamide-binding site of PDK1, and subsequently inhibits the interaction of PDK1 with the E2 subunit of PDH complex. As a result of PDK1 inhibition, lactate production was decreased, but oxygen consumption was increased. Mitochondrial ROS levels and mitochondrial damage were also increased. Consistent with these observations, the apoptosis of colorectal cancer cells was promoted by HsA with enhanced activation of caspase-3 and -9. These results suggested that HsA might be a potential candidate for developing a novel anti-cancer drug through suppressing cancer metabolism.

Survival prediction in patients with colon adenocarcinoma via multi-omics data integration using a deep learning algorithm

This study proposed a deep learning (DL) algorithm to predict survival in patients with colon adenocarcinoma (COAD) based on multi-omics integration. The survival-sensitive model was constructed using an autoencoder for DL implementation based on The Cancer Genome Atlas (TCGA) data of patients with COAD. The autoencoder framework was compared to PCA, NMF, t-SNE, and univariable Cox-PH model for identifying survival-related features. The prognostic robustness of the inferred survival risk groups was validated using three independent confirmation cohorts. Differential expression analysis, Pearson's correlation analysis, construction of miRNA-target gene network, and function enrichment analysis were performed. Two risk groups with significant survival differences were identified in TCGA set using the autoencoder-based model (log-rank p-value = 5.51e-07). The autoencoder framework showed superior performance compared to PCA, NMF, t-SNE, and the univariable Cox-PH model based on the C-index, log-rank p-value, and Brier score. The robustness of the classification model was successfully verified in three independent validation sets. There were 1271 differentially expressed genes, 10 differentially expressed miRNAs, and 12 hypermethylated genes between the survival risk groups. Among these, miR-133b and its target genes (GNB4, PTPRZ1, RUNX1T1, EPHA7, GPM6A, BICC1, and ADAMTS5) were used to construct a network. These genes were significantly enriched in ECM-receptor interaction, focal adhesion, PI3K-Akt signaling pathway, and glucose metabolism-related pathways. The risk subgroups obtained through a multi-omics data integration pipeline using the DL algorithm had good robustness. miR-133b and its target genes could be potential diagnostic markers. The results would assist in elucidating the possible pathogenesis of COAD.

Free fatty acids receptors 2 and 3 control cell proliferation by regulating cellular glucose uptake

BACKGROUND

Colorectal cancer (CRC) is a worldwide problem, which has been associated with changes in diet and lifestyle pattern. As a result of colonic fermentation of dietary fibres, short chain free fatty acids are generated which activate free fatty acid receptors (FFAR) 2 and 3. FFAR2 and FFAR3 genes are abundantly expressed in colonic epithelium and play an important role in the metabolic homeostasis of colonic epithelial cells. Earlier studies point to the involvement of FFAR2 in colorectal carcinogenesis.

AIM

To understand the role of short chain FFARs in CRC.

METHODS

Transcriptome analysis console software was used to analyse microarray data from CRC patients and cell lines. We employed short-hairpin RNA mediated down regulation of FFAR2 and FFAR3 genes, which was validated using quantitative real time polymerase chain reaction. Assays for glucose uptake and cyclic adenosine monophosphate (cAMP) generation was done along with immunofluorescence studies to study the effects of FFAR2/FFAR3 knockdown. For measuring cell proliferation, we employed real time electrical impedance-based assay available from xCELLigence.

RESULTS

Microarray data analysis of CRC patient samples showed a significant down regulation of FFAR2 gene expression. This prompted us to study the FFAR2 in CRC. Since, FFAR3 shares significant structural and functional homology with FFAR2, we knocked down both these receptors in CRC cell line HCT 116. These modified cell lines exhibited higher proliferation rate and were found to have increased glucose uptake as well as increased level of glucose transporter 1. Since, FFAR2 and FFAR3 signal through G protein subunit (Gαi), knockdown of these receptors was associated with increased cAMP. Inhibition of protein kinase A (PKA) did not alter the growth and proliferation of these cells indicating a mechanism independent of cAMP/PKA pathway.

CONCLUSION

Our results suggest role of FFAR2/FFAR3 genes in increased proliferation of colon cancer cells via enhanced glucose uptake and exclude the role of PKA mediated cAMP signalling. Alternate pathways could be involved that would ultimately result in increased cell proliferation as a result of down regulated FFAR2/FFAR3 genes. This study paves the way to understand the mechanism of action of short chain FFARs in CRC.

Mitochondrial Respiration in KRAS and BRAF Mutated Colorectal Tumors and Polyps

This study aimed to characterize the ATP-synthesis by oxidative phosphorylation in colorectal cancer (CRC) and premalignant colon polyps in relation to molecular biomarkers KRAS and BRAF. This prospective study included 48 patients. Resected colorectal polyps and postoperative CRC tissue with adjacent normal tissue (control) were collected. Patients with polyps and CRC were divided into three molecular groups: KRAS mutated, BRAF mutated and KRAS/BRAF wild-type. Mitochondrial respiration in permeabilized tissue samples was observed using high resolution respirometry. ADP-activated respiration rate (V_max) and an apparent affinity of mitochondria to ADP, which is related to mitochondrial outer membrane (MOM) permeability, were determined. Clear differences were present between molecular groups. KRAS mutated CRC group had lower V_max values compared to wild-type; however, the V_max value was higher than in the control group, while MOM permeability did not change. This suggests that KRAS mutation status might be involved in acquiring oxidative phenotype. KRAS mutated polyps had higher V_max values and elevated MOM permeability as compared to the control. BRAF mutated CRC and polyps had reduced respiration and altered MOM permeability, indicating a glycolytic phenotype. To conclude, prognostic biomarkers KRAS and BRAF are likely related to the metabolic phenotype in CRC and polyps. Assessment of the tumor mitochondrial ATP synthesis could be a potential component of patient risk stratification.

Glucose restriction combined with chemotherapy decreases telomere length and cancer antigen-125 secretion in ovarian carcinoma

Although chemotherapy is the standard treatment for ovarian cancer (OC), recent studies have focused on its coupling with hypoglycemic drugs to decrease glucose availability. Similarly to cancer antigen 125 (Ca-125), telomerase, the key protein for telomere lengthening, is overexpressed in 90% of OC cases. The aim of the present study was to investigate the effect of the combination of glucose restriction and chemotherapy on telomere length and Ca-125 secretion in OC cells. SKOV-3, OVCAR-3 and Igrov-1 cells were treated with 20 µM cisplatin and 100 nM paclitaxel for 48 h in three different glucose concentrations: i) 4.5 g/l, ii) 1 g/l and iii) 0.5 g/l. The same treatment was repeated once per week for 6 consecutive weeks. The surviving cells were considered platinum-taxane escape (PTES) cells. The expression levels of telomerase and Ca-125 in treated and PTES cells were quantified by qPCR, and Ca-125 secretion by ELISA. Telomere length was evaluated by qPCR according to the Cawthon method. The modulation of Ca-125 by telomerase was assessed using inhibitors, small interfering RNA and transfection with human telomerase reverse transcriptase (hTERT) vectors. The implication of phosphatidylinositol-4,5-bisphosphate 3-kinase/protein kinase B/mechanistic target of rapamycin (PI3K/Akt/mTOR) in Ca-125 modulation was investigated using specific inhibitors. An increase in hTERT and Ca-125 expression levels (range, 1.5-3 fold) was observed in short-term treated cells. However, an opposite effect was detected in PTES cells, where the rate of decrease in the expression levels of hTERT and Ca-125 reached 60% after treatment in 0.5 g/l glucose. Moreover, telomere length was decreased by 30% in cells treated with 0.5 g/l glucose. Inhibition of hTERT expression significantly decreased Ca-125 secretion, suggesting a potential modulation of Ca-125 by hTERT. The inhibition of the PI3K/Akt/mTOR pathway also decreased Ca-125 secretion; however, the effect of this treatment was not enhanced when coupled with telomerase inhibitors. In conclusion, the combination of chemotherapy and glucose restriction was observed to decrease Ca-125 secretion and telomerase expression leading to shortening in telomere length. Thus, decreasing glucose availability for OC cells during treatment may lead to a better clinical outcome and potentially improve the prognosis of patients with OC.

Colorectal cancer stem cells properties and features: evidence of interleukin-8 involvement

Colorectal cancer (CRC) still remains a disease with high percentage of death, principally due to therapy resistance and metastasis. During the time the hypothesis has been reinforced that CRC stem cells (CRCSC) are involved in allowing intratumoral heterogeneity, drug escape mechanisms and secondary tumors. CRCSC are characterized by specific surface markers (i.e., CD44 and CD133), signaling pathways activation (i.e., Wnt and Notch) and gene expression (i.e., Oct4 and Snail), which confer to CRCSC self-renewal abilities and pluripotent capacity. Interleukin (IL)-8 is correlated to CRC progression, development of liver metastases and chemoresistance; moreover, IL-8 modulates not only stemness maintenance but also stemness promotion, such as epithelial-mesenchymal transition. This review wants to give a brief and up-to-date overview on IL-8 implication in CRCSC cues.

Reverse Warburg Effect-Related Mitochondrial Activity and 18F-FDG Uptake in Invasive Ductal Carcinoma

Purpose

We evaluated the relationship between fluorine-18 fluoro-2-deoxy-glucose (¹⁸F-FDG) uptake and mitochondrial activity in cancer cells and investigated the prognostic implications of this relationship in patients with invasive ductal carcinoma of the breast (IDCB).

Methods

One hundred forty-six patients with primary IDCB who underwent preoperative ¹⁸F-FDG PET/CT followed by curative surgical resection were enrolled in the current study. Mitochondrial activity of cancer cells was assessed based on translocase of outer mitochondrial membrane 20 (TOMM20) expression and cytochrome C oxidase (COX) activity. A Pearson's correlation analysis was used to assess the relationship between the maximum standardized uptake value of the primary tumour (pSUVmax) and mitochondrial activity. Clinicopathological factors, including pSUVmax, histological grade, oestrogen receptor (ER), progesterone receptor (PR), and TOMM20 expression; and COX activity, were assessed for the prediction of disease-free survival (DFS) using the Kaplan-Meier method and Cox proportional hazards model.

Results

Fourteen of the 146 subjects (9.6%) showed tumour recurrence. There was a significant positive correlation between ¹⁸F-FDG uptake and the mitochondrial activity of cancer cells in patients with IDCB, and increased ¹⁸F-FDG uptake and mitochondrial activity were significantly associated with a shorter DFS. Additionally, results from the receiver-operating curve analysis demonstrated that the cut-off values of pSUVmax, TOMM20 expression, and COX activity for the prediction of DFS were 7.76, 4, and 5, respectively. Further, results from the univariate analysis revealed that pSUVmax, TOMM20 expression, PR status, and histologic grade were significantly associated with DFS; however, the multivariate analysis revealed that only pSUVmax was associated with DFS (HR, 6.51; 95% CI, 1.91, 22.20; P = 0.003).

Conclusions

The assessment of preoperative ¹⁸F-FDG uptake and post-surgical mitochondrial activity may be used for the prediction of DFS in patients with IDCB.

pathfindR: An R Package for Comprehensive Identification of Enriched Pathways in Omics Data Through Active Subnetworks

Pathway analysis is often the first choice for studying the mechanisms underlying a phenotype. However, conventional methods for pathway analysis do not take into account complex protein-protein interaction information, resulting in incomplete conclusions. Previously, numerous approaches that utilize protein-protein interaction information to enhance pathway analysis yielded superior results compared to conventional methods. Hereby, we present pathfindR, another approach exploiting protein-protein interaction information and the first R package for active-subnetwork-oriented pathway enrichment analyses for class comparison omics experiments. Using the list of genes obtained from an omics experiment comparing two groups of samples, pathfindR identifies active subnetworks in a protein-protein interaction network. It then performs pathway enrichment analyses on these identified subnetworks. To further reduce the complexity, it provides functionality for clustering the resulting pathways. Moreover, through a scoring function, the overall activity of each pathway in each sample can be estimated. We illustrate the capabilities of our pathway analysis method on three gene expression datasets and compare our results with those obtained from three popular pathway analysis tools. The results demonstrate that literature-supported disease-related pathways ranked higher in our approach compared to the others. Moreover, pathfindR identified additional pathways relevant to the conditions that were not identified by other tools, including pathways named after the conditions.

Colorectal Cancer and Metabolism

Purpose of Review

Metabolic reprogramming is essential for the rapid proliferation of cancer cells and is thus recognized as a hallmark of cancer. In this review, we will discuss the etiologies and effects of metabolic reprogramming in colorectal cancer.

Recent Findings

Changes in cellular metabolism may precede the acquisition of driver mutations ultimately leading to colonocyte transformation. Oncogenic mutations and loss of tumor suppressor genes further reprogram CRC cells to upregulate glycolysis, glutaminolysis, one-carbon metabolism, and fatty acid synthesis. These metabolic changes are not uniform throughout tumors, as subpopulations of tumor cells may rely on different pathways to adapt to nutrient availability in the local tumor microenvironment. Finally, metabolic cross-communication between stromal cells, immune cells, and the gut microbiota enable CRC growth, invasion, and metastasis.

Summary

Altered cellular metabolism occurs in CRC at multiple levels, including in the cells that make up the bulk of CRC tumors, cancer stem cells, the tumor microenvironment, and host-microbiome interactions. This knowledge may inform the development of improved screening and therapeutics for CRC.

Ascorbic Acid in Colon Cancer: From the Basic to the Clinical Applications

Given the safety and potential benefits of intravenous ascorbic acid (AA) administration in cancer patients, there is merit in further exploring this therapeutic concept. In this review, we discuss the potential benefits of intravenous AA administration on colorectal cancer and we specifically focus on its effect on glycolysis in mutant and wild type RAS. We perform a PubMed and Ovid MEDLINE search using ascorbic acid, intravenous vitamin C, KRAS mutation, BRAF mutation and colorectal cancer (CRC) as keywords. At the cellular level, colorectal cancer cells undergo a metabolic shift called the Warburg effect to allow for more glucose absorption and utilization of glycolysis. This shift also allows AA to enter which leads to a disruption in the Warburg effect and a shutdown of the downstream KRAS pathway in mutated KRAS colon cancer cells. At the clinical level, AA is associated with tumour regression in advanced disease and improved tolerability and side effects of standard therapy. Based on these findings, we conclude that further clinical trials are needed on a larger scale to examine the therapeutic benefits of AA in colon cancer.

New strategies for targeting glucose metabolism-mediated acidosis for colorectal cancer therapy

Colorectal cancer (CRC) is a heterogeneous group of diseases that are the result of abnormal glucose metabolism alterations with high lactate production by pyruvate to lactate conversion, which remodels acidosis and offers an evolutional advantage for tumor cells, even enhancing their aggressive phenotype. This review summarizes recent findings that involve multiple genes, molecules, and downstream signaling in the dysregulated glycolytic pathway, which can allow a tumor to initiate acid byproducts and to progress, thereby resulting in acidosis commonly found in the tumor microenvironment of CRC. Moreover, the relationship between CRC cells and the tumor acidic microenvironment, especially for regulating lactate production and lactate dehydrogenase A levels, is also discussed, as well as comprehensively defining different aspects of glycolytic pathways that affect cancer cell proliferation, invasion, and migration. Furthermore, this review concentrates on glucose metabolism-mediated transduction factors in CRC, which include acid-sensing ion channels, triosephosphate isomerase and key glycolysis-related enzymes that regulate glycolytic metabolites, coupled with the effect on tumor cell glycolysis as well as signaling pathways. In conclusion, glucose metabolism mediated by glycolytic pathways that are integral to tumor acidosis in CRC is demonstrated. Therefore, selective metabolic inhibitors or agents against these targets in glucose metabolism through glycolytic pathways may be clinically useful to regulate the tumor's acidic microenvironment for CRC treatment and to identify specific targets that regulate tumor acidosis through a cancer patient-personalized approach. Furthermore, strategies for modifying the metabolic processes that effectively inhibit cancer cell growth and tumor progression and activate potent anticancer effects may provide more effective antitumor prospects for CRC therapy.

Antiproliferative effect of p-Coumaric acid targets UPR activation by downregulating Grp78 in colon cancer

p-CA is a naturally occurring phenolic acid present in most plants and in all commonly consumed vegetables and fruits. Here we demonstrated the anti-cancer effect of the food borne phytochemical p-CA both in vitro and in vivo models of colon cancer using growth rate and tumor incidence as endpoints. Glucose regulated protein (GRP78) induction and UPR activation plays a key role in oncogenic progression, therefore increased dependence of cancer cells on these UPR signaling pathways for survival can be exploited for anti-cancer research. Hence we investigated the effect of p-CA on Grp78 a molecular chaperone often upregulated in colon cancer and its impact on unfolded protein response (UPR). Administration of the procarcinogen 1,2- dimethylhydrazine (DMH) causes Grp78 upregulation and tumor adaptation via UPR activation. The adaptive activity of UPR activates antiapoptotic NF-κB that results in upregulation of the markers of inflammation and angiogenesis. Supplementation of p-CA downregulated Grp78 and activated UPR mediated apoptosis both in in vitro and in vivo models of colon cancer. Further we observed that p-CA significantly reduced inflammation by decreasing the expression of cytokines COX-2, IL-6, TNF-α and PGE2 as analyzed by q-PCR and also reduced the expression of p-p65 and p-IκBα as analyzed by western blot. Further mechanistic insights revealed that p-CA inhibits Grp78 upregulation in cancer cells through activation of PERK-eIF2α-ATF-4-CHOP pathway that culminates in apoptosis inducing effect of p-CA.

Clinical laboratory and imaging evidence for effectiveness of agarose-agarose macrobeads containing stem-like cells derived from a mouse renal adenocarcinoma cell population (RMBs) in treatment-resistant, advanced metastatic colorectal cancer: Evaluation of a biological-systems approach to cancer therapy (U.S. FDA IND-BB 10091; NCT 02046174, NCT 01053013)

Objective

The complexity, heterogeneity and capacity of malignant neoplastic cells and tumors for rapid change and evolution suggest that living-cell-based biological-systems approaches to cancer treatment are merited. Testing this hypothesis, the tumor marker, metabolic activity, and overall survival (OS) responses, to the use of one such system, implantable macrobeads [RENCA macrobeads (RMBs)], in phase I and IIa clinical trials in advanced, treatment-resistant metastatic colorectal cancer (mCRC) are described here.

Methods

Forty-eight mCRC patients (30 females; 18 males), who had failed all available, approved treatments, underwent RMB implantation (8 RMB/kg body weight) up to 4 times in phase I and phase IIa open-label trials. Physicals, labs [tumor and inflammation markers, lactate dehydrogenase (LDH)] and positron emission tomography-computed tomography (PET-CT) imaging to measure number/volume and metabolic activity of the tumors were performed pre- and 3-month-post-implantation to evaluate safety and initial efficacy (as defined by biological responses). PET-CT maximum standard uptake value (SUV_max) (baseline and d 90; SUV_max ≥2.5), LDH, and carcinoembryonic antigen (CEA) and/or cancer antigen 19-9 (CA 19-9) response (baseline, d 30 and/or d 60) were assessed and compared to OS.

Results

Responses after implantation were characterized by an at least 20% decrease in CEA and/or CA 19-9 in 75% of patients. Fluorodeoxyglucose (FDG)-positive lesions (phase I, 39; 2a, 82) were detected in 37/48 evaluable patients, with 35% stable volume and stable or decreased SUV (10) plus four with necrosis; 10, increased tumor volume, SUV. LDH levels remained stable and low in Responders (R) (d 0-60, 290.4-333.9), but increased steadily in Non-responders (NR) (d 0-60, 382.8-1,278.5) (d 60, P=0.050). Responders to RMBs, indicated by the changes in the above markers, correlated with OS (R mean OS=10.76 months; NR mean OS=4.9 months; P=0.0006).

Conclusions

The correlations of the tumor marker, tumor volume and SUV changes on PET-CT, and LDH levels themselves, and with OS, support the concept of a biological response to RMB implantation and the validity of the biological-systems approach to mCRC. A phase III clinical trial is planned.

Phosphorylation of Ser6 in hnRNPA1 by S6K2 regulates glucose metabolism and cell growth in colorectal cancer

Abnormal glucose metabolism is critical in colorectal cancer (CRC) development. Expression of the pyruvate kinase (PK) M2 isoform, rather than the PKM1 isoform, serves important functions in reprogramming the glucose metabolism of cancer cells. Preferential expression of PKM2 is primarily driven by alternative splicing, which is coordinated by a group of splicing factors including heterogeneous nuclear ribonucleoprotein (hnRNP)A1, hnRNPA2 and RNA binding motif containing. However, the underlying molecular mechanisms associated with cancer cell expression of PKM2, instead of PKM1, remain unknown. The mRNA levels of PKM isoform and glucose metabolism were analyzed in CRC cells. The results of the present study indicated that S6 kinase 2 (S6K2) promotes glycolysis and growth of CRC cells by regulating alternative splicing of the PKM gene. In addition, chromatin immunoprecipitation assay indicated that S6K2 phosphorylation of Ser⁶ of hnRNPA1 facilitated hnRNPA1 binding to the splicing site of the PKM gene. As a result, cancer cells preferentially expressed the PKM2 isoform, instead of the PKM1 isoform. Furthermore, Cox regression analysis demonstrated that the phosphorylation of Ser⁶ of hnRNPA1 was a predictor of poor prognosis for patients with CRC. Therefore, the results of the present study revealed that the phosphorylation of Ser⁶ in hnRNPA1 by S6K2 was a novel mechanism underlying glucose metabolic reprogramming, and suggested that S6K2 is a potential therapeutic target for CRC treatment.

Role of glucose metabolism related gene GLUT1 in the occurrence and prognosis of colorectal cancer

Colorectal cancer (CRC) ranks the third most commonly diagnosed cancer in males and the second in females worldwide. However, the functional and causal SNPs for CRC remain to be mined. Glucose transporter 1 (GLUT1), a pivotal rate-limiting element in the transport of glucose in malignancy cells, has been identified to be associated with many cancers. Here, we aim to explore the role of GLUT1 in the occurrence and prognosis of colorectal cancer in a Chinese population. We found that GLUT1 expression levels in CRC tumor tissues were significantly higher than those in the corresponding adjacent normal tissues, and Cox multivariate analysis demonstrated that the GLUT1 expression was an independent prognostic factor for CRC (HR = 2.11, 95% CI = 1.33–3.34, P=0.001). For a functional polymorphism of GLUT1 (rs710218), we found that individuals with TT genotype (OR = 1.68, 95% CI = 1.02-2.75, P = 0.041) or AT genotype (OR = 1.47, 95% CI = 1.09-1.99, P = 0.012) of rs710218 had a significantly increased risk of CRC compared to those with AA homozygote. These findings strongly suggest that glucose metabolism related gene GLUT1, and its functional SNP, rs710218 might contribute to CRC susceptibility and prognosis, and the exact biological mechanism awaits further research.

Methylglyoxal-Mediated Stress Correlates with High Metabolic Activity and Promotes Tumor Growth in Colorectal Cancer

Cancer cells generally rely on aerobic glycolysis as a major source of energy. Methylglyoxal (MG), a dicarbonyl compound that is produced as a side product during glycolysis, is highly reactive and induces the formation of advanced glycation end-products that are implicated in several pathologies including cancer. All mammalian cells have an enzymatic defense against MG composed by glyoxalases GLO1 and GLO2 that converts MG to d-lactate. Colorectal cancer (CRC) is one of the most frequently occurring cancers with high morbidity and mortality. In this study, we used immunohistochemistry to examine the level of MG protein adducts, in a series of 102 CRC human tumors divided into four clinical stages. We consistently detected a high level of MG adducts and low GLO1 activity in high stage tumors compared to low stage ones suggesting a pro-tumor role for dicarbonyl stress. Accordingly, GLO1 depletion in CRC cells promoted tumor growth in vivo that was efficiently reversed using carnosine, a potent MG scavenger. Our study represents the first demonstration that MG adducts accumulation is a consistent feature of high stage CRC tumors. Our data point to MG production and detoxification levels as an important molecular link between exacerbated glycolytic activity and CRC progression.

Validity and clinical impact of glucose transporter 1 expression in colorectal cancer

BACKGROUND/AIM

There is no doubt that colorectal cancer (CRC) poses a major threat to public health worldwide, and despite improvement in managements, prognosis still remains an irritating question with no definite answer. Being a fundamental player in cancer metabolism, glucose transporter 1 (GLUT1) could be utilized as a prognostic biomarker that could fuel development of new treatment strategies. The aim of this study was to assess the validity of GLUT1 expression as a prognostic biomarker and to elucidate to what extent it is immersed in poor clinical outcome among CRC patients.

PATIENTS AND METHODS

GLUT1 expression in peripheral blood specimens was analyzed by quantitative real-time polymerase chain reaction in 47 CRC patients and 20 healthy controls.

RESULTS

There was significantly elevated GLUT1 expression in peripheral blood of CRC patients than in controls (P < 0.001). The cutoff value of 0.605 provided 98% sensitivity and 100% specificity. There were significantly higher values of GLUT1 expression in patients under 50 years (P = 0.003), performance status 2 (P = 0.009), stage IV (P < 0.001), and presence of metastasis (P < 0.001). GLUT1 expression showed nonsignificant association with overall survival (P = 0.068), while tumor stage (P = 0.01) and metastasis (P = 0.009) were significantly associated with lower overall survival.

CONCLUSION

GLUT1 is sensitive and specific marker for CRC. It is overexpressed in young age patients, poor performance status, and stage IV patients. Although this was not statistically significant, GLUT 1 showed higher expression level in patients with lesser survival.