Understanding the Warburg effect and the prognostic value of stromal caveolin-1 as a marker of a lethal tumor microenvironment

Assessing the Prognostic Value of Cytoplasmic and Stromal Caveolin-1 in Early Triple-Negative Breast Cancer Undergoing Neoadjuvant Chemotherapy

Triple-negative breast cancer (TNBC) is a highly aggressive subtype with limited therapeutic options, leading to higher relapse rates and mortality. Identifying prognostic biomarkers like caveolin-1 (CAV1) is crucial for personalized treatment. CAV1 influences tumor progression and chemotherapy response, particularly through its interaction with the tumor microenvironment (TME) and cancer metabolism. Understanding the prognostic value of CAV1 in different cellular compartments is essential for its clinical application in TNBC. In the methods section CAV1 gene expression in TNBC was evaluated using in silico analysis, followed by the immunohistochemical staining of tumor cytoplasm (cCAV1) and stromal cells (sCAV1) in 58 early-stage TNBC patients. Statistical analyses were performed to correlate CAV1 expression with clinicopathological features and survival. In the results section, in silico analysis revealed higher CAV1 expression in TNBC, correlating with shorter overall survival. In the patient samples, cCAV1 was observed in 10.3% of cases, and was associated with larger tumors, higher grades, and poorer prognoses. sCAV1 was detected in 42% of cases, associated with less proliferative and less aggressive tumors, but did not significantly impact prognoses. In conclusion, cCAV1 expression is a significant prognostic marker in early-stage TNBC, highlighting the importance of assessing CAV1 in different cellular compartments. Further research is needed to explore the mechanisms and clinical implications of cCAV1.

Mitophagy: insights into its signaling molecules, biological functions, and therapeutic potential in breast cancer

Mitophagy, a form of selective autophagy that removes damaged or dysfunctional mitochondria, plays a crucial role in maintaining mitochondrial and cellular homeostasis. Recent findings suggest that defective mitophagy is closely associated with various diseases, including breast cancer. Moreover, a better understanding of the multifaceted roles of mitophagy in breast cancer progression is crucial for the treatment of this disease. Here, we will summarize the molecular mechanisms of mitophagy process. In addition, we highlight the expression patterns and roles of mitophagy-related signaling molecules in breast cancer progression and the potential implications of mitophagy for the development of breast cancer, aiming to provide better therapeutic strategies for breast cancer treatment.

Extracellular glucose triggers metabolic reprogramming of cultured human bronchial epithelial cells and indirect fibroblast activation

Glucose is essential for energy metabolism, and its usage can determine other cellular functions, depending on the cell type. In some pathological conditions, cells are exposed to high concentrations of glucose for extended periods. In this study, we investigated metabolic, oxidative stress, and cellular senescence pathways in human bronchial epithelial cells (HBECs) cultured in media with physiologically low (5 mm) and high (12.5 mm) glucose concentrations. HBECs exposed to 12.5 mm glucose showed increased glucose routing toward the pentose phosphate pathway, lactate synthesis, and glycogen, but not triglyceride synthesis. These metabolic shifts were not associated with changes in cell proliferation rates, oxidative stress, or cellular senescence pathways. Since hyperglycemia is associated with fibrosis in the lung, we asked whether HBECS could activate fibroblasts. Primary human lung fibroblasts cultured in media conditioned by 12.5 mm glucose-exposed HBECs showed a 1.3-fold increase in the gene expression of COL1A1 and COL1A2, along with twofold increased protein levels of smooth muscle cell actin and 2.4-fold of COL1A1. Consistently, HBECs cultured with 12.5 mm glucose secreted proteins associated with inflammation and fibrosis, such as interleukins IL-1β, IL-10, and IL-13, CC chemokine ligands CCL2 and CCL24, and with extracellular matrix remodeling, such as metalloproteinases (MMP)-1, MMP-3, MMP-9, and MMP-13 and tissue inhibitors of MMPs (TIMP)-1 and -2. This study shows that HBECs undergo metabolic reprogramming and increase the secretion of profibrotic mediators following exposure to high concentrations of glucose, and it contributes to the understanding of the metabolic crosstalk of neighboring cells in diabetes-associated pulmonary fibrosis.

Antioxidant and antiproliferative effects of Teucrium polium extract: computational and in vivo study in rats

The current study aimed to assess the antioxidant and antiproliferative effects of teucrium polium extract: computational and in vivo study in rats. Three groups of animals: Group (i) constitute the control group; Group (ii) HeLa group received an intrafemoral inoculation of HeLa cells and Group (iii) constitue the combination between HeLa + T. polium. The plant was administered by gavage. Our results revealed that HeLa cell injection showed an elevation in aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), total bilirubin (TB), creatinine, urea, calcium and phosphorus. The pretreatment with the plant extract reduced the level of these parameters. Injection of HeLa cells showed a significant decrease in phosphorus and calcium respectively. However, the pretreatment by T. polium modulated the level of these two minerals. Rats treated with HeLa cells line showed an increase in the level of lipid peroxidation as evaluated by the TBARS substances, at the same time, a significant decreases in SOD, CAT and GPx activities were noted in the HeLa group compared to the control. On the other hand, pretreatment with the plant improved the level of these enzymes. Our results revealed that T.polium has a therapeutic effect on some health problems. HeLa cell line induced a small infiltration in liver and kidney. T. polium reduced the damage in both liver and kidney, but did not reveal any proliferation of tumor cells from trabecular bone tissue. The computational study revealed that T. polium compound bound with high free binding energies and established promising network of molecular interactions with COX-2 and TNF-α macromolecules.

Predictive, preventive, and personalized medicine in breast cancer: targeting the PI3K pathway

Breast cancer (BC) is a multifaceted disease characterized by distinct molecular subtypes and varying responses to treatment. In BC, the phosphatidylinositol 3-kinase (PI3K) pathway has emerged as a crucial contributor to the development, advancement, and resistance to treatment. This review article explores the implications of the PI3K pathway in predictive, preventive, and personalized medicine for BC. It emphasizes the identification of predictive biomarkers, such as PIK3CA mutations, and the utility of molecular profiling in guiding treatment decisions. The review also discusses the potential of targeting the PI3K pathway for preventive strategies and the customization of therapy based on tumor stage, molecular subtypes, and genetic alterations. Overcoming resistance to PI3K inhibitors and exploring combination therapies are addressed as important considerations. While this field holds promise in improving patient outcomes, further research and clinical trials are needed to validate these approaches and translate them into clinical practice.

Identification of hub genes and drug candidates for NF2-related vestibular schwannoma by bioinformatics tools

Neurofibromatosis type 2 (NF2)-related vestibular schwannoma (NF2-VS) is a rare genetic disorder that results in bilateral acoustic neuromas. However, the exact pathogenesis of the disease is still unclear. This study aims to use bioinformatics analyses to identify potential hub genes and therapeutic. We retrieved the mRNA expression profiles (GSE108524 and GSE141801) of NF2-VS from the database, and selected the leading 25% genes with the most variance across samples for weighted correlation network analysis. Subsequently, we conducted gene ontology term and Kyoto Encyclopedia of Genes and Genomes signaling network enrichment analyses. The STRING database was employed for protein-protein interaction (PPI) axis construction. The mRNA-miRNA modulatory network was generated via the miRTarBase database. Differentially expressed genes (DEGs) were identified via the R package "limma" in both datasets, and hub genes were screened via intersection of common DEGs, candidate hub genes from the PPI axis, and candidate hub genes from the key module. Finally, common DEGs were uploaded onto the connectivity map database to determine drug candidates. Based on our observations, the blue module exhibited the most significant relation to NF2-VS, and it included the NF2 gene. Using enrichment analysis, we demonstrated that the blue modules were intricately linked to modulations of cell proliferation, migration, adhesion, junction, and actin skeleton. Overall, 356 common DEGs were screened in both datasets, and 33 genes carrying a degree > 15 were chosen as candidate hub genes in the PPI axis. Subsequently, 4 genes, namely, GLUL, CAV1, MYH11, and CCND1 were recognized as real hub genes. In addition, 10 drugs with enrichment scores < -0.7 were identified as drug candidates. Our conclusions offered a novel insight into the potential underlying mechanisms behind NF2-VS. These findings may facilitate the identification of novel therapeutic targets in the future.

Plant extract from Caesalpinia spinosa inhibits cancer-associated fibroblast-like cells generation and function in a tumor microenvironment model

Interactions in the tumor microenvironment (TME) between tumor cells and stromal cells such as cancer-associated fibroblasts (CAF) favor increased survival, progression, and transformation of cancer cells by activating mechanisms of invasion and metastasis. The design of new therapies to modulate or eliminate the CAF phenotype or functionality has been the subject of recent research including natural product-based therapies. We have previously described the generation of a standardized extract rich in polyphenols obtained from the Caesalpinia spinosa plant (P2Et), which present antitumor activities in breast cancer and melanoma models through activities that modulate the metabolism of tumor cells or induce the development of the immune response. In this work, a model of CAF generation was initially developed from the exposure of 3T3 fibroblasts to the cytokine TGFβ1. CAF-like cells generated in this way exhibited changes in the expression of Caveolin-1 and α-SMA, and alterations in glucose metabolism and redox status, typical of CAFs isolated from tumor tissues. Then, P2Et was shown to counteract in vitro-induced CAF-like cell generation, preventing caveolin-1 loss and attenuating changes in glucose uptake and redox profile. This protective effect of P2Et translates into a decrease in the functional ability of CAFs to support colony formation and migration of 4T1 murine breast cancer tumor cells. In addition to the functional interference, the P2Et extract also decreased the expression of genes associated with the epithelial-mesenchymal transition (EMT) and functional activities related to the modulation of the cancer stem cells (CSC) population. This work is an in vitro approach to evaluate natural extracts' effect on the interaction between CAF and tumor cells in the tumor microenvironment; thus, these results open the chance to design a more profound and mechanistic analysis to explore the molecular mechanisms of P2Et multimolecular activity and extent this analysis to an in vivo perspective. In summary, we present here a standardized polymolecular natural extract that has the potential to act in the TME by interfering with CAF generation and functionality.

Cancer-Associated Adipocytes and Breast Cancer: Intertwining in the Tumor Microenvironment and Challenges for Cancer Therapy

Adipocytes are the main components in breast tissue, and cancer-associated adipocytes (CAAs) are one of the most important components in the tumor microenvironment of breast cancer (BC). Bidirectional regulation was found between CAAs and BC cells. BC facilitates the dedifferentiation of adjacent adipocytes to form CAAs with morphological and biological changes. CAAs increase the secretion of multiple cytokines and adipokines to promote the tumorigenesis, progression, and metastasis of BC by remodeling the extracellular matrix, changing aromatase expression, and metabolic reprogramming, and shaping the tumor immune microenvironment. CAAs are also associated with the therapeutic response of BC and provide potential targets in BC therapy. The present review provides a comprehensive description of the crosstalk between CAAs and BC and discusses the potential strategies to target CAAs to overcome BC treatment resistance.

Emerging role of substance and energy metabolism associated with neuroendocrine regulation in tumor cells

Cancer is the second most common cause of mortality in the world. One of the unresolved difficult pathological mechanism issues in malignant tumors is the imbalance of substance and energy metabolism of tumor cells. Cells maintain life through energy metabolism, and normal cells provide energy through mitochondrial oxidative phosphorylation to generate ATP, while tumor cells demonstrate different energy metabolism. Neuroendocrine control is crucial for tumor cells' consumption of nutrients and energy. As a result, better combinatorial therapeutic approaches will be made possible by knowing the neuroendocrine regulating mechanism of how the neuroendocrine system can fuel cellular metabolism. Here, the basics of metabolic remodeling in tumor cells for nutrients and metabolites are presented, showing how the neuroendocrine system regulates substance and energy metabolic pathways to satisfy tumor cell proliferation and survival requirements. In this context, targeting neuroendocrine regulatory pathways in tumor cell metabolism can beneficially enhance or temper tumor cell metabolism and serve as promising alternatives to available treatments.

Exosomal microRNAs synergistically trigger stromal fibroblasts in breast cancer

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype. TNBC progression is sustained by recruitment of a strong tumor microenvironment (TME) mainly composed of cancer-associated fibroblasts (CAFs) able to endorse tumor hallmarks. Increasing evidences demonstrate that exosomes mediate the crosstalk between cancer cells and the TME. We examined TNBC-derived exosomes and their microRNA (miRNA) cargo in activation of normal fibroblasts (NFs) toward CAFs. We demonstrated that TNBC cell-derived exosomes increased NF collagen contraction and migration alongside CAF molecular markers. Exosome-activated fibroblasts promoted the invasion potential of normal breast epithelial cells, as assessed by an organotypic co-culture assay that resembled the in vivo context. We also investigated TNBC cell-derived exosome cargo in activating NFs to CAFs by performing small RNA sequencing. We found that the synergistic action of miR-185-5p, miR-652-5p, and miR-1246 boosted fibroblast migration and contraction, promoting specific CAF subspecialization toward a pro-migratory functional state. These data highlight the role of breast cancer cells in re-education of the TME and their contribution to tumor evolution.

A Novel Immune-Related Gene Signature Predicts Prognosis of Lung Adenocarcinoma

Background

Lung adenocarcinoma (LUAD) is the most common form of lung cancer, accounting for 30% of all cases and 40% of all non-small-cell lung cancer cases. Immune-related genes play a significant role in predicting the overall survival and monitoring the status of the cancer immune microenvironment. The present study was aimed at finding an immune-related gene signature for predicting LUAD patient outcomes.

Methods

First, we chose the TCGA-LUAD project in the TCGA database as the training cohort for model training. For model validating, we found the datasets of GSE72094 and GSE68465 in the GEO database and took them as the candidate cohorts. We obtained 1793 immune-related genes from the ImmPort database and put them into a univariate Cox proportional hazard model to initially look for the genes with potential prognostic ability using the data of the training cohort. These identified genes then entered into a random survival forests-variable hunting algorithm for the best combination of genes for prognosis. In addition, the LASSO Cox regression model tested whether the gene combination can be further shrinkage, thereby constructing a gene signature. The Kaplan-Meier, Cox model, and ROC curve were deployed to examine the gene signature's prognosis in both cohorts. We conducted GSEA analysis to study further the mechanisms and pathways that involved the gene signature. Finally, we performed integrating analyses about the 22 TICs, fully interpreted the relationship between our signature and each TIC, and highlighted some TICs playing vital roles in the signature's prognostic ability.

Results

A nine-gene signature was produced from the data of the training cohort. The Kaplan-Meier estimator, Cox proportional hazard model, and ROC curve confirmed the independence and predictive ability of the signature, using the data from the validation cohort. The GSEA analysis results illustrated the gene signature's mechanism and emphasized the importance of immune-related pathways for the gene signature. 22 TICs immune infiltration analysis revealed resting mast cells' key roles in contributing to gene signature's prognostic ability.

Conclusions

This study discovered a novel immune-related nine-gene signature (BTK, CCR6, S100A10, SEMA3C, GPI, SCG2, TNFRSF11A, CCL20, and DKK1) that predicts LUAD prognosis precisely and associates with resting mast cells strongly.

Quantification of doping state of redox sensitive nanoparticles for probing the invasiveness of cancer cells using surface enhanced Raman scattering

Redox activity is known to regulate migration, invasion, metastasis, proliferation, and vascularization of cancer. Because cancer is heterogeneous, the role of redox activity in different cancers and cancer-related processes vary widely. In this study, water soluble, Tween 80-coated polyaniline (TPAni) nanoparticles were synthesized and used as nano-agents for sensing the redox activities of various cancer cells. To identify the relationship between the redox activity and the aggressiveness of cancer cells, two different cancer cell lines, derived from the same tissue but different with regards to aggressiveness, were selected for study. First, the cancer cell lines were incubated with TPAni nanoparticles, and an absorbance ratio obtained from the cell culture media was used as a colorimetric indicator of the redox activities of the cells. Simultaneously, hydrophobically modified filter papers coated with silver nanosnowflakes (SNSF) were used as sensing substrates for surface enhanced Raman scattering (SERS). SERS spectra obtained from varying concentrations of rhodamine 6G were used to confirm the detection limit of the SNSF-based SERS substrate. Cell culture media containing TPAni nanoparticles were treated with the SNSF-containing SERS substrates to examine the redox activities of the various cancer cell lines.The redox activities of cancer cell lines were confirmed by absorbance spectral analysis, and these redox activities were better identified via an SERS analysis method. A SNSF-containing SERS substrate, fabricated from SNSF and filter paper, was used to sense redox activity in cancer cell lines and to further identify correlations between redox activity and cancer cell line aggressiveness, as indicated by the use of EpCAM as a biomarker. Finally, potential of ​in vivo ​redox activity sensing was also confirmed.

Stromal Fibroblasts Counteract the Caveolin-1-Dependent Radiation Response of LNCaP Prostate Carcinoma Cells

In prostate cancer (PCa), a characteristic stromal–epithelial redistribution of the membrane protein caveolin 1 (CAV1) occurs upon tumor progression, where a gain of CAV1 in the malignant epithelial cells is accompanied by a loss of CAV1 in the tumor stroma, both facts that were correlated with higher Gleason scores, poor prognosis, and pronounced resistance to therapy particularly to radiotherapy (RT). However, it needs to be clarified whether inhibiting the CAV1 gain in the malignant prostate epithelium or limiting the loss of stromal CAV1 would be the better choice for improving PCa therapy, particularly for improving the response to RT; or whether ideally both processes need to be targeted. Concerning the first assumption, we investigated the RT response of LNCaP PCa cells following overexpression of different CAV1 mutants. While CAV1 overexpression generally caused an increased epithelial-to-mesenchymal phenotype in respective LNCaP cells, effects that were accompanied by increasing levels of the 5′-AMP-activated protein kinase (AMPK), a master regulator of cellular homeostasis, only wildtype CAV1 was able to increase the three-dimensional growth of LNCaP spheroids, particularly following RT. Both effects could be limited by an additional treatment with the SRC inhibitor dasatinib, finally resulting in radiosensitization. Using co-cultured (CAV1-expressing) fibroblasts as an approximation to the in vivo situation of early PCa it could be revealed that RT itself caused an activated, more tumor-promoting phenotype of stromal fibroblats with an increased an increased metabolic potential, that could not be limited by combined dasatinib treatment. Thus, targeting fibroblasts and/or limiting fibroblast activation, potentially by limiting the loss of stromal CAV1 seems to be absolute for inhibiting the resistance-promoting CAV1-dependent signals of the tumor stroma.

Caveolae-Associated Molecules, Tumor Stroma, and Cancer Drug Resistance: Current Findings and Future Perspectives

Simple Summary

Cell membranes contain small invaginations called caveolae. They are a specialized lipid domain and orchestrate cellular signaling events, mechanoprotection, and lipid homeostasis. Formation of the caveolae depends on two classes of proteins, the caveolins and cavins, which form large complexes that allow their self-assembly into caveolae. Loss of either of these two proteins leads to distortion of the caveolae structure and disruption of many physiological processes that affect diseases of the muscle, metabolic states governing lipids, and the glucose balance as well as cancers. In cancers, the expression of caveolins and cavins is heterogenous, and they undergo alterations both in the tumors and the surrounding tumor microenvironment stromal cells. Remarkably, their expression and function has been associated with resistance to many cancer drugs. Here, we summarize the current knowledge of the resistance mechanisms and how this knowledge could be applied into the clinic in future.

Abstract

The discovery of small, “cave-like” invaginations at the plasma membrane, called caveola, has opened up a new and exciting research area in health and diseases revolving around this cellular ultrastructure. Caveolae are rich in cholesterol and orchestrate cellular signaling events. Within caveola, the caveola-associated proteins, caveolins and cavins, are critical components for the formation of these lipid rafts, their dynamics, and cellular pathophysiology. Their alterations underlie human diseases such as lipodystrophy, muscular dystrophy, cardiovascular disease, and diabetes. The expression of caveolins and cavins is modulated in tumors and in tumor stroma, and their alterations are connected with cancer progression and treatment resistance. To date, although substantial breakthroughs in cancer drug development have been made, drug resistance remains a problem leading to treatment failures and challenging translation and bench-to-bedside research. Here, we summarize the current progress in understanding cancer drug resistance in the context of caveola-associated molecules and tumor stroma and discuss how we can potentially design therapeutic avenues to target these molecules in order to overcome treatment resistance.

Hypoxia-related prognostic model in bladder urothelial reflects immune cell infiltration

Hypoxia is a common feature of tumor microenvironment (TME). This study aims to establish the genetic features related to hypoxia in Bladder urothelial carcinoma (BLCA) and investigate the potential correlation with hypoxia in the TME and immune cells. We established a BLCA outcome model using the hypoxia-related genes from The Cancer Genome Atlas using regression analysis and verified the model using the Gene Expression Omnibus GSE32894 cohort. We measured the effect of each gene in the hypoxia-related risk model using the Human Protein Atlas website. The predictive abilities were compared using the area under the receiver operating characteristic curves. Gene Set Enrichment Analysis was utilized for indicating enrichment pathways. We analyzed immune cell infiltration between risk groups using the CIBERSORT method. The indicators related to immune status between the two groups were also analyzed. The findings indicated that the high-risk group had better outcomes than the low-risk group in the training and validation sets. Each gene in the model affected the survival of BLCA patients. Our hypoxia-related risk model had better performance compared to other hypoxia-related markers (HIF-1α and GLUT-1). The high-risk group was enriched in immune-related pathways. The expression of chemokines and immune cell markers differed significantly between risk groups. Immune checkpoints were more highly expressed in the high-risk group. These findings suggest that the hypoxia-related risk model predicts patients' outcomes and immune status in BLCA risk groups. Our findings may contribute to the treatment of BLCA.

E-Cadherin Regulates Mitochondrial Membrane Potential in Cancer Cells

Epithelial cancer cells often have unusually higher mitochondrial membrane potential (ΔΨ_m) than their normal counterparts, which has been associated with increased invasiveness in vitro and higher metastatic potential in vivo. However, the mechanisms by which ΔΨ_m in cancer cells is regulated in tumor microenvironment (TME) remain unclear. In this study, we used an in vitro micropatterning platform to recapitulate biophysical confinement cues in the TME and investigated the mechanisms by which these regulate cancer cell ΔΨ_m. We found that micropatterning resulted in a spatial distribution of ΔΨ_m, which correlated with the level of E-cadherin mediated intercellular adhesion. There was a stark contrast in the spatial distribution of ΔΨ_m in the micropattern of E-cadherin-negative breast cancer cells (MDA-MB-231) compared to that of the high E-cadherin expressing (MCF-7) cancer cells. Disruption and knockout of E-cadherin adhesions rescued the low ΔΨ_m found at the center of MCF-7 micropatterns with high E-cadherin expression, while E-cadherin overexpression in MDA-MB-231 and MCF-7 cells lowered their ΔΨ_m at the micropattern center. These results show that E-cadherin plays an important role in regulating the ΔΨ_m of cancer cells in the context of biophysical cues in TME.

Metabolic perturbations in fibrosis disease

Metabolic changes occur in all forms of disease but their impact on fibrosis is a relatively recent area of interest. This review provides an overview of the major metabolic pathways, glycolysis, amino acid metabolism and lipid metabolism, and highlights how they influence fibrosis at a cellular and tissue level, drawing on key discoveries in dermal, renal, pulmonary and hepatic fibrosis. The emerging influence of adipose tissue-derived cytokines is discussed and brings a link between fibrosis and systemic metabolism. To close, the concept of targeting metabolism for fibrotic therapy is reviewed, drawing on lessons from the more established field of cancer metabolism, with an emphasis on important considerations for clinical translation.

Stemness of Human Pluripotent Cells: Hypoxia-Like Response Induced by Low Nitric Oxide

The optimization of conditions to promote the stemness of pluripotent cells in vitro is instrumental for their use in advanced therapies. We show here that exposure of human iPSCs and human ESCs to low concentrations of the chemical NO donor DETA/NO leads to stabilization of hypoxia-inducible factors (HIF-1α and HIF-2α) under normoxia, with this effect being dependent on diminished Pro 402 hydroxylation and decreased degradation by the proteasome. Moreover, the master genes of pluripotency, NANOG and OCT-4, were upregulated. NO also induces a shift in the metabolic profile of PSCs, with an increased expression of hypoxia response genes in glycolysis. Furthermore, a reduction in the mitochondrial membrane potential with lower oxygen consumption and increased expression of mitochondrial fusion regulators, such as DRP1, was observed. The results reported here indicate that NO mimics hypoxia response in human PSCs and enhances their stemness properties when cultured under normoxic conditions.

Protein networks linking Warburg and reverse Warburg effects to cancer cell metabolism

It was 80 years after the Otto Warburg discovery of aerobic glycolysis, a major hallmark in the understanding of cancer. The Warburg effect is the preference of cancer cell for glycolysis that produces lactate even when sufficient oxygen is provided. "reverse Warburg effect" refers to the interstitial tissue communications with adjacent epithelium, that in the process of carcinogenesis, is needed to be explored. Among these cell-cell communications, the contact between epithelial cells; between epithelial cells and matrix; and between fibroblasts and inflammatory cells in the underlying matrix. Cancer involves dysregulation of Warburg and reverse Warburg cellular metabolic pathways. How these gene and protein-based regulatory mechanisms have functioned has been the basis for this review. The importance of the Warburg in oxidative phosphorylation suppression, with increased glycolysis in cancer growth and proliferation is emphasized. Studies that are directed at pathways that would be expected to shift cell metabolism to an increased oxidation and to a decrease in glycolysis are emphasized. Key enzymes required for oxidative phosphorylation, and affect the inhibition of fatty acid metabolism and glutamine dependence are conferred. The findings are of special interest to cancer pharmacotherapy. Studies described in this review are concerned with the effects of therapeutic modalities that are intimately related to the Warburg effect. These interactions described may be helpful as adjuvant therapy in controlling the process of proliferation and metastasis.

Development and Validation of a Robust Ferroptosis-Related Prognostic Signature in Lung Adenocarcinoma

Background

Lung adenocarcinoma (LUAD) is the most common subtype of non-small cell lung cancer. Ferroptosis is a newly recognized process of cell death, which is different from other forms of cell death in morphology, biochemistry, and genetics, and has played a vital role in cancer biology. This study aimed to identify a ferroptosis-related gene signature associated with LUAD prognosis.

Methods

Dataset TCGA-LUAD which came from the TCGA portal was taken as the training cohort. GSE72094 and GSE68465 from the GEO database were treated as validation cohorts. Two hundred fifty-nine ferroptosis-related genes were retrieved from the FerrDb database. In the training cohort, Kaplan–Meier and univariate Cox analyses were conducted for preliminary screening of ferroptosis-related genes with potential prognostic capacity. These genes then entered into the LASSO Cox regression model, constructing a gene signature. The latter was then evaluated in the training and validation cohorts via Kaplan–Meier, Cox, and ROC analyses. In addition, the correlations between risk score and autophagy were examined by Pearson correlation coefficient. The analyses of GSEA and immune infiltrating were performed for better studying the function annotation of the gene signature and the character of each kind of immune cells played in the tumor microenvironment.

Results

A 15-gene signature was found from the training cohort and validated by Kaplan–Meier and Cox regression analyses, revealing its independent prognosis value in LUAD. Moreover, the ROC analysis was conducted, confirming a strong predictive ability that this signature owned for LUAD prognosis. One hundred fifty-one of 222 (68.01%) autophagy-related genes were discovered significantly correlated with risk scores. Analyses of GSEA and immune infiltration exhibited in detail the specific pathways that associate with the 15-gene signature and identified the crucial roles of resting mast cells and resting dendritic cells owned in the prognosis of the 15-gene signature.

Conclusion

In this present study, a novel ferroptosis-related 15-gene signature (RELA, ACSL3, YWHAE, EIF2S1, CISD1, DDIT4, RRM2, PANX1, TLR4, ARNTL, LPIN1, HERPUD1, NCOA4, PEBP1, and GLS2) was built. It could accurately predict the prognosis of LUAD and was related to resting mast cells and resting dendritic cells, which provide potential for the personalized outcome prediction and the development of new therapies in LUAD population.

Cancer-Associated Fibroblasts in the Breast Tumor Microenvironment

Years of investigation have shed light on a theory in which breast tumor epithelial cells are under the effect of the stromal microenvironment. This review aims to discuss recent findings concerning the phenotypic and functional characteristics of cancer associated fibroblasts (CAFs) and their involvement in tumor evolution, as well as their potential implications for anti-cancer therapy. In this manuscript, we reviewed that CAFs play a fundamental role in initiation, growth, invasion, and metastasis of breast cancer, and also serve as biomarkers in the clinical diagnosis, therapy, and prognosis of this disease.

Hyperpolarized 13C Magnetic Resonance Spectroscopic Imaging of Pyruvate Metabolism in Murine Breast Cancer Models of Different Metastatic Potential

This study uses dynamic hyperpolarized [1-¹³C]pyruvate magnetic resonance spectroscopic imaging (MRSI) to estimate differences in glycolytic metabolism between highly metastatic (4T1, n = 7) and metastatically dormant (4T07, n = 7) murine breast cancer models. The apparent conversion rate of pyruvate-to-lactate (k_PL) and lactate-to-pyruvate area-under-the-curve ratio (AUC_L/P) were estimated from the metabolite images and compared with biochemical metabolic measures and immunohistochemistry (IHC). A non-significant trend of increasing k_PL (p = 0.17) and AUC_L/P (p = 0.11) from 4T07 to 4T1 tumors was observed. No significant differences in tumor IHC lactate dehydrogenase-A (LDHA), monocarboxylate transporter-1 (MCT1), cluster of differentiation 31 (CD31), and hypoxia inducible factor-α (HIF-1α), tumor lactate-dehydrogenase (LDH) activity, or blood lactate or glucose levels were found between the two tumor lines. However, AUC_L/P was significantly correlated with tumor LDH activity (ρ_spearman = 0.621, p = 0.027) and blood glucose levels (ρ_spearman = −0.474, p = 0.042). k_PL displayed a similar, non-significant trend for LDH activity (ρ_spearman = 0.480, p = 0.114) and blood glucose levels (ρ_spearman = −0.414, p = 0.088). Neither k_PL nor AUC_L/P were significantly correlated with blood lactate levels or tumor LDHA or MCT1. The significant positive correlation between AUC_L/P and tumor LDH activity indicates the potential of AUC_L/P as a biomarker of glycolytic metabolism in breast cancer models. However, the lack of a significant difference between in vivo tumor metabolism for the two models suggest similar pyruvate-to-lactate conversion despite differing metastatic potential.

Potential Mechanism Underlying the Role of Mitochondria in Breast Cancer Drug Resistance and Its Related Treatment Prospects

Breast cancer incidence and mortality rates have been consistently high among women. The use of diverse therapeutic strategies, including chemotherapy, endocrine therapy, targeted therapy, and immunotherapy, has improved breast cancer prognosis. However, drug resistance has become a tremendous obstacle in overcoming breast cancer recurrence and metastasis. It is known that mitochondria play an important role in carcinoma cell growth, invasion and apoptosis. Recent studies have explored the involvement of mitochondrial metabolism in breast cancer prognosis. Here, we will provide an overview of studies that investigated mitochondrial metabolism pathways in breast cancer treatment resistance, and discuss the application prospects of agents targeting mitochondrial pathways against drug-resistant breast cancer.

Cancer-Associated Fibroblasts Suppress Cancer Development: The Other Side of the Coin

Cancer-associated fibroblasts (CAFs) are the main stromal components of cancer, representing a group of heterogeneous cells. Many studies indicate that CAFs promote tumor development. Besides, evidence of the tumor suppression effects of CAFs keeps on merging. In the tumor microenvironment, multiple stimuli can activate fibroblasts. Notably, this does not necessarily mean the activated CAFs become strong tumor promoters immediately. The varying degree of CAFs activation makes quiescent CAFs, tumor-restraining CAFs, and tumor-promoting CAFs. Quiescent CAFs and tumor-restraining CAFs are more present in early-stage cancer, while comparatively, more tumor-promoting CAFs present in advanced-stage cancer. The underlying mechanism that balances tumor promotion or tumor inhibition effects of CAFs is mostly unknown. This review focus on the inhibitory effects of CAFs on cancer development. We describe the heterogeneous origin, markers, and metabolism in the CAFs population. Transgenetic mouse models that deplete CAFs or deplete CAFs activation signaling in the tumor stroma present direct evidence of CAFs protective effects against cancer. Moreover, we outline CAFs subpopulation and CAFs derived soluble factors that act as a tumor suppressor. Single-cell RNA-sequencing on CAFs population provides us new insight to classify CAFs subsets. Understanding the full picture of CAFs will help translate CAFs biology from bench to bedside and develop new strategies to improve precision cancer therapy.

Tyrosine phosphorylation of tumor cell caveolin-1: impact on cancer progression

Caveolin-1 (CAV1) has long been implicated in cancer progression, and while widely accepted as an oncogenic protein, CAV1 also has tumor suppressor activity. CAV1 was first identified in an early study as the primary substrate of Src kinase, a potent oncoprotein, where its phosphorylation correlated with cellular transformation. Indeed, CAV1 phosphorylation on tyrosine-14 (Y14; pCAV1) has been associated with several cancer-associated processes such as focal adhesion dynamics, tumor cell migration and invasion, growth suppression, cancer cell metabolism, and mechanical and oxidative stress. Despite this, a clear understanding of the role of Y14-phosphorylated pCAV1 in cancer progression has not been thoroughly established. Here, we provide an overview of the role of Src-dependent phosphorylation of tumor cell CAV1 in cancer progression, focusing on pCAV1 in tumor cell migration, focal adhesion signaling and metabolism, and in the cancer cell response to stress pathways characteristic of the tumor microenvironment. We also discuss a model for Y14 phosphorylation regulation of CAV1 effector protein interactions via the caveolin scaffolding domain.

The Role of Vitamin E in Breast Cancer Treatment and Prevention: Current Perspectives

Background:

Regarding the multifactorial etiology of breast cancer, food choices, as well as dietary intake, are the main modified factors in cancer prevention. In this sense, understanding molecular pathways involved in breast cancer proliferation can help determine the mechanisms of action of organic compounds such as antioxidant vitamins that are known to protect against cancer.

Objective:

Assess the mechanism of action of vitamin E in breast cancer modulation, with emphasis on important markers of tumor development.

Methods:

It is a systematic review carried out in PubMed and Web of Science databases, from the last 5 years, in Portuguese, English and Spanish. The following terms were selected according to The Medical Subject Headings (MeSH): “breast cancer” OR “breast neoplasms”, “tocopherol” OR “tocotrienols” OR “vitamin E”, as equated terms.

Results:

A total of 595 articles were found and 25 were selected according to inclusion criteria. Vitamin E has been related to suppression/overexpression of important tumorigenic pathways, mainly associated with proliferation, energy metabolism, chemosensitivity and invasion/metastasis. Clinical studies of vitamin E supplementation are needed to assess the dose/response effect on breast cancer patients.

Conclusion:

The safety of vitamin E supplementation is still controversial due to current studies design available. However, when vitamin E is supplemented, the dose and therapeutic regimen must be carefully decided, including the route of administration and breast cancer subtypes to enhance desired effects and minimize unwanted side effects.

The metabolic importance of the glutaminase II pathway in normal and cancerous cells

In rapidly dividing cells, including many cancer cells, l-glutamine is a major energy source. Utilization of glutamine is usually depicted as: l-glutamine → l-glutamate (catalyzed by glutaminase isozymes; GLS1 and GLS2), followed by l-glutamate → α-ketoglutarate [catalyzed by glutamate-linked aminotransferases or by glutamate dehydrogenase (GDH)]. α-Ketoglutarate is a major anaplerotic component of the tricarboxylic acid (TCA) cycle. However, the glutaminase II pathway also converts l-glutamine to α-ketoglutarate. This pathway consists of a glutamine transaminase coupled to ω-amidase [Net reaction: l-Glutamine + α-keto acid + H₂O → α-ketoglutarate + l-amino acid + NH₄⁺]. This review focuses on the biological importance of the glutaminase II pathway, especially in relation to metabolism of cancer cells. Our studies suggest a component enzyme of the glutaminase II pathway, ω-amidase, is utilized by tumor cells to provide anaplerotic carbon. Inhibitors of GLS1 are currently in clinical trials as anti-cancer agents. However, this treatment will not prevent the glutaminase II pathway from providing anaplerotic carbon derived from glutamine. Specific inhibitors of ω-amidase, perhaps in combination with a GLS1 inhibitor, may provide greater therapeutic efficacy.

Multimodal cellular redox nanosensors based on self-doped polyaniline nanocomposites

We have successfully fabricated a nanocomposite, which is composed of polyaniline (PAni) and pyrene butyric acid (Pyba) via a solvent shift method, which was self-doped at a neutral pH value. This PAni nanocomposite can act as a fine nanoagent expressing absorbance, fluorescence, and Raman properties according to the surrounding pH values.

Mitochondria Autoimmunity and MNRR1 in Breast Carcinogenesis: A Review

We review here the evidence for participation of mitochondrial autoimmunity in BC inception and progression and propose a new paradigm that may challenge the prevailing thinking in oncogenesis by suggesting that mitochondrial autoimmunity is a major contributor to breast carcinogenesis and probably to the inception and progression of other solid tumors. It has been shown that MNRR1 mediated mitochondrial-nuclear function promotes BC cell growth and migration and the development of metastasis and constitutes a proof of concept supporting the participation of mitochondrial autoimmunity in breast carcinogenesis. The resemblance of the autoantibody profile in BC detected by IFA with that in the rheumatic autoimmune diseases suggested that studies on the autoantibody response to tumor associated antigens and the characterization of the mtDNA- and nDNA-encoded antigens may provide functional data on breast carcinogenesis. We also review the studies supporting the view that a panel of autoreactive nDNA-encoded mitochondrial antigens in addition to MNRR1 may be involved in breast carcinogenesis. These include GAPDH, PKM2, GSTP1, SPATA5, MFF, ncRNA PINK1-AS/DDOST as probably contributing to BC progression and metastases and the evidence suggesting that DDX21 orchestrates a complex signaling network with participation of JUND and ATF3 driving chronic inflammation and breast tumorigenesis. We suggest that the widespread autoreactivity of mtDNA- and nDNA-encoded mitochondrial proteins found in BC sera may be the reflection of autoimmunity triggered by mitochondrial and non-mitochondrial tumor associated antigens involved in multiple tumorigenic pathways. Furthermore, we suggest that mitochondrial proteins may contribute to mitochondrial dysfunction in BC even if mitochondrial respiration is found to be within normal limits. However, although the studies show that mitochondrial autoimmunity is a major factor in breast cancer inception and progression, it is not the only factor since there is a multiplex autoantibody profile targeting centrosome and stem cell antigens as well as anti-idiotypic antibodies, revealing the complex signaling network involved in breast carcinogenesis. In summary, the studies reviewed here open new, unexpected therapeutic avenues for cancer prevention and treatment of patients with cancer derived from an entirely new perspective of breast carcinogenesis.

Power of two: combination of therapeutic approaches involving glucose transporter (GLUT) inhibitors to combat cancer

Cancer research of the Warburg effect, a hallmark metabolic alteration in tumors, focused attention on glucose metabolism whose targeting uncovered several agents with promising anticancer effects at the preclinical level. These agents' monotherapy points to their potential as adjuvant combination therapy to existing standard chemotherapy in human trials. Accordingly, several studies on combining glucose transporter (GLUT) inhibitors with chemotherapeutic agents, such as doxorubicin, paclitaxel, and cytarabine, showed synergistic or additive anticancer effects, reduced chemo-, radio-, and immuno-resistance, and reduced toxicity due to lowering the therapeutic doses required for desired chemotherapeutic effects, as compared with monotherapy. The combinations have been specifically effective in treating cancer glycolytic phenotypes, such as pancreatic and breast cancers. Even combining GLUT inhibitors with other glycolytic inhibitors and energy restriction mimetics seems worthwhile. Though combination clinical trials are in the early phase, initial results are intriguing. The various types of GLUTs, their role in cancer progression, GLUT inhibitors, and their anticancer mechanism of action have been reviewed several times. However, utilizing GLUT inhibitors as combination therapeutics has received little attention. We consider GLUT inhibitors agents that directly affect glucose transporters by binding to them or indirectly alter glucose transport by changing the transporters' expression level. This review mainly focuses on summarizing the effects of various combinations of GLUT inhibitors with other anticancer agents and providing a perspective on the current status.

Unidirectional Regulation of Vimentin Intermediate Filaments to Caveolin-1

Both the mechanosensitive vimentin cytoskeleton and endocytic caveolae contribute to various active processes such as cell migration, morphogenesis, and stress response. However, the crosstalk between these two systems has remained elusive. Here, we find that the subcellular expression between vimentin and caveolin-1 is mutual exclusive, and vimentin filaments physically arrest the cytoplasmic motility of caveolin-1 vesicles. Importantly, vimentin depletion increases the phosphorylation of caveolin-1 on site Tyr14, and restores the compromised cell migration rate and directionality caused by caveolin-1 deprivation. Moreover, upon hypo-osmotic shock, vimentin-knockout recovers the reduced intracellular motility of caveolin-1 vesicles. In contrary, caveolin-1 depletion shows no effect on the expression, phosphorylation (on sites Ser39, Ser56, and Ser83), distribution, solubility, and cellular dynamics of vimentin filaments. Taken together, our data reveals a unidirectional regulation of vimentin to caveolin-1, at least on the cellular level.

Low levels of AMPK promote epithelial-mesenchymal transition in lung cancer primarily through HDAC4- and HDAC5-mediated metabolic reprogramming

AMP-activated protein kinase (AMPK) serves as a "supermetabolic regulator" that helps maintain cellular energy homeostasis. However, the role of AMPK in glucose metabolism reprogramming in lung cancer remains unclear. Here, our study shows that low AMPK expression correlates with metastasis and clinicopathologic parameters of non-small-cell lung cancer. Low AMPK significantly enhances the Warburg effect in HBE and A549 cells, which in turn induces the expression of mesenchymal markers and enhances their invasion and migration. At the mechanistic level, low AMPK up-regulates HK2 expression and glycolysis levels through HDAC4 and HDAC5. Collectively, our findings demonstrate that low AMPK-induced metabolism can promote epithelial-mesenchymal transition progression in normal bronchial epithelial cells and lung cancer cells, and increase the risk for tumour metastasis.

Expression of Caveolin-1 Is Associated With Thyroid Function in Patients With Human Papillary Thyroid Carcinoma

Objective:

The aim of this study was to evaluate the levels of caveolin-1 in thyroid follicular epithelial cells of papillary thyroid cancer, follicular thyroid cancer, and nonmalignant thyroid nodule benign follicular adenoma, as well as to explore the relationship between the levels of caveolin-1 and thyroid function.

Methods:

Thirty cases of papillary thyroid cancer, 10 cases of follicular thyroid cancer, 32 cases of nonmalignant thyroid nodule benign follicular adenoma, and 30 controls were enrolled in this study. Caveolin-1 expression in tissue specimens obtained from these cases was evaluated by immunohistochemistry and Western blotting.

Results:

Caveolin-1 expression in thyroid epithelial cells of patients with papillary thyroid cancer, particularly female patients, was significantly higher than that in patients with follicular thyroid cancer and nonmalignant thyroid nodule benign follicular adenoma (P < .005). Serum thyroid-stimulating hormone (TSH) levels in the caveolin-1-positive expression group were lower than that in the caveolin-1-negative expression group, and the lowest expression of caveolin-1 was detected in tissues of patients with Graves’ disease. The serum TSH level was associated with caveolin-1 expression in thyroid epithelial cells.

Conclusion:

Caveolin-1 may participate in regulating thyroid function and is a potential biomarker of follicular thyroid cancer.

Cancer associated fibroblasts as novel promising therapeutic targets in breast cancer

Breast cancer is one of the most important women-related malignancies, which is incurable (particularly in advanced stages) and tumor microenvironment is a number one accused part in the inefficiency of current anti-breast cancer therapeutic strategies. The tumor microenvironment is composed of various cellular and acellular components, which provide an optimum condition for freely expanding cancer cells in various cancer types, particularly breast cancer. Cancer-associated fibroblasts (CAFs) are one of the main cell types in the breast tumor region, which can promote various tumor-promoting processes such as expansion, angiogenesis, metastasis and drug resistance. CAFs directly (by cell-to-cell communication) and indirectly (through secreting soluble factors) can exert their tumorigenic functions. We try to elucidate the immunobiology of CAFs, their origin, function, and heterogeneity in association with their role in various cancer-promoting processes in breast cancer. Based on current knowledge, we believe that the origin of CAFs, their subsets, and their specific expressed biomarkers determine their pro- or anti-tumor functions. Therefore, targeting CAF without considering their specific functions may lead to a deleterious outcome. We propose to find and characterize each subtype of CAFs in association with its specific function in different stages of breast cancer to develop novel promising therapeutic approaches against the right CAF subtype.

The Molecular Mechanism of Metabolic Remodeling in Lung Cancer

Metabolic remodeling is a key phenomenon in the occurrence and development of tumors. It not only offers materials and energy for the survival and proliferation of tumor cells, but also protects tumor cells so that they may survive, proliferate and transfer in the harsh microenvironment. This paper attempts to reveal the role of abnormal metabolism in the development of lung cancer by considering the processes of glycolysis and lipid metabolism, Identification of the molecules that are specifically used in the processes of glycolysis and lipid metabolism, and their underlying molecular mechanisms, is of great clinical and theoretical significance. We will focus on the recent progress in elucidating the molecular mechanism of metabolic remodeling in lung cancer.

Targeting Glucose Transporters for Breast Cancer Therapy: The Effect of Natural and Synthetic Compounds

Reprogramming of cellular energy metabolism is widely accepted to be a cancer hallmark. The deviant energetic metabolism of cancer cells-known as the Warburg effect-consists in much higher rates of glucose uptake and glycolytic oxidation coupled with the production of lactic acid, even in the presence of oxygen. Consequently, cancer cells have higher glucose needs and thus display a higher sensitivity to glucose deprivation-induced death than normal cells. So, inhibitors of glucose uptake are potential therapeutic targets in cancer. Breast cancer is the most commonly diagnosed cancer and a leading cause of cancer death in women worldwide. Overexpression of facilitative glucose transporters (GLUT), mainly GLUT1, in breast cancer cells is firmly established, and the consequences of GLUT inhibition and/or knockout are under investigation. Herein we review the compounds, both of natural and synthetic origin, found to interfere with uptake of glucose by breast cancer cells, and the consequences of interference with that mechanism on breast cancer cell biology. We will also present data where the interaction with GLUT is exploited in order to increase the efficiency or selectivity of anticancer agents, in breast cancer cells.

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.

Cancer-associated adipocytes: key players in breast cancer progression

Adipocytes are one of the primary stromal cells in many tissues, and they are considered to play an active role in the tumor microenvironment. Cancer-associated adipocytes (CAAs) are not only found adjacent to cancer cells, but also communicate with cancer cells through releasing various factors that can mediate local and systemic effects. The adipocyte-cancer cell crosstalk leads to phenotypical and functional changes of both cell types, which can further enhance tumor progression. Indeed, obesity, which is associated with an increase in adipose mass and an alteration of adipose tissue, is becoming pandemic in some countries and it is now considered to be an independent risk factor for cancer progression. In this review, we focus on the potential mechanisms involved with special attention to the adipocyte-cancer cell circle in breast cancer. We envisage that besides having a direct impact on tumor cells, CAAs systemically preconditions the tumor microenvironment by favoring anti-tumor immunity. A better understanding of cancer-associated adipocytes and the key molecular events in the adipocyte-cancer cell crosstalk will provide insights into tumor biology and permit the optimization of therapeutic strategies.

The Milk Protein Alpha-Casein Suppresses Triple Negative Breast Cancer Stem Cell Activity Via STAT and HIF-1alpha Signalling Pathways in Breast Cancer Cells and Fibroblasts

Triple negative breast cancer (TNBC) is the most lethal breast cancer subtype. Extended periods of lactation protect against breast cancer development, but the mechanisms underlying this protection are unknown. We examined the effects of the milk protein alpha-casein over expression in the triple negative MDA-MB-231 breast cancer cell line. The effects of recombinant alpha-casein added exogenously to MDA-MB-231 breast cancer cells, and immortalised human fibroblasts were also investigated. We used transcriptional reporters to understand the signalling pathways downstream of alpha-casein in breast cancer cells and these fibroblasts that were activated by breast cancer cells. To extend our findings to the clinical setting, we analysed public gene expression datasets to further understand the relevance of these signalling pathways in triple negative breast cancer cells and patient samples. Finally, we used small molecular inhibitors to target relevant pathways and highlight these as potential candidates for the treatment of TN breast cancer. High levels of alpha-casein gene expression were predictive of good prognosis across 263 TNBC patient tumour samples. Alpha-casein over expression or exogenous addition reduces cancer stem cell (CSC) activity. HIF-1alpha was identified to be a key downstream target of alpha-casein, in both breast cancer cells and activated fibroblasts, and STAT transcription factors to be upstream of HIF-1alpha. Interestingly, HIF-1alpha is regulated by STAT3 in breast cancer cells, but STAT1 is the regulator of HIF-1alpha in activated fibroblasts. In analysis of 573 TNBC patient samples, alpha-casein expression, inversely correlated to HIF-1alpha, STAT3 and STAT1. STAT1 and STAT3 inhibitors target HIF-1alpha signalling in activated fibroblasts and MDA-MB-231 breast cancer cells respectively, and also abrogate CSC activities. Our findings provide an explanation for the protective effects of lactation in TNBC. Clinical data correlates high alpha-casein expression with increased recurrence-free survival in TNBC patients. Mechanistically, alpha-casein reduces breast cancer stem cell activity in vitro, and STAT3 and STAT1 were identified as regulators of pro-tumorigenic HIF-1alpha signalling in breast cancer cells and fibroblasts respectively.

Pharmacologic treatment with CPI-613 and PS48 decreases mitochondrial membrane potential and increases quantity of autolysosomes in porcine fibroblasts

A metabolic phenomenon known as the Warburg effect has been characterized in certain cancerous cells, embryonic stem cells, and other rapidly proliferative cell types. Previously, our attempts to induce a Warburg-like state pharmaceutically via CPI-613 and PS48 treatment did augment metabolite production and gene expression; however, this treatment demonstrated a Reverse Warburg effect phenotype observed in cancer-associated stroma. In the current study, we inquired whether the mitochondria were affected by the aforementioned pharmaceutical treatment as observed in cancerous stromal fibroblasts. While the pharmaceutical agents decreased mitochondrial membrane potential in porcine fetal fibroblasts, the number and size of mitochondria were similar, as was the overall cell size. Moreover, the fibroblasts that were treated with CPI-613 and PS48 for a week had increased numbers of large autolysosome vesicles. This coincided with increased intensity of LysoTracker staining in treated cells as observed by flow cytometry. Treated fibroblasts thus may utilize changes in metabolism and autophagy to mitigate the damage of treatment with pharmaceutical agents. These findings shed light on how these pharmaceutical agents interact and how treated cells augment metabolism to sustain viability.

Caveolin-1 enhances brain metastasis of non-small cell lung cancer, potentially in association with the epithelial-mesenchymal transition marker SNAIL

Background

Caveolin-1 (Cav-1) plays an important role in the development of various human cancers. We investigated the relationship between Cav-1 expression and non-small cell lung cancer (NSCLC) progression in the context of brain metastasis (BM).

Methods

Cav-1 expression was investigated in a series of 102 BM samples and 49 paired primary NSCLC samples, as well as 162 unpaired primary NSCLC samples with (63 cases) or without (99 cases) metastasis to distant organs. Human lung cancer cell lines were used for in vitro functional analysis.

Results

High Cav-1 expression in tumor cells was observed in 52% (38/73) of squamous cell carcinomas (SQCs) and 33% (45/138) of non-SQCs. In SQC, high Cav-1 expression was increased after BM in both paired and unpaired samples of lung primary tumors and BM (53% vs. 84% in paired samples, P = 0.034; 52% vs. 78% in unpaired samples, P = 0.020). Although the difference in median overall survival in patients NSCLC was not statistically significant, high Cav-1 expression in tumor cells (P = 0.005, hazard ratio 1.715, 95% confidence index 1.175–2.502) was independent prognostic factors of overall survival on multivariate Cox regression analyses, in addition to the presence of BM and non-SQC type. In vitro assays revealed that Cav-1 knockdown inhibited the invasion and migration of lung cancer cells. Genetic modulation of Cav-1 was consistently associated with SNAIL up- and down-regulation. These findings were supported by increased SNAIL and Cav-1 expression in BM samples of SQC.

Conclusions

Cav-1 plays an important role in the BM of NSCLC, especially in SQC. The mechanism may be linked to SNAIL regulation.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0892-0) contains supplementary material, which is available to authorized users.

Fibroblasts as Modulators of Local and Systemic Cancer Metabolism

Fibroblast activation is an accompanying feature of solid tumor progression, resembling a conserved host response to tissue damage. Cancer-associated fibroblasts (CAFs) comprise a heterogeneous and plastic population with increasingly appreciated roles in tumor growth, metastatic capacity, and response to therapy. Classical features of fibroblasts in a wound-healing response, including profound extracellular matrix production and cytokine release, are recapitulated in cancer. Emerging evidence suggests that fibroblastic cells in the microenvironments of solid tumors also critically modulate cellular metabolism in the neoplastic compartment through mechanisms including paracrine transfer of metabolites or non-cell-autonomous regulation of metabolic signaling pathways. These metabolic functions may represent common mechanisms by which fibroblasts stimulate growth of the regenerating epithelium during a wound-healing reaction, or may reflect unique co-evolution of cancer cells and surrounding stroma within the tumor microenvironment. Here we review the recent literature supporting an important role for CAFs in regulation of cancer cell metabolism, and relevant pathways that may serve as targets for therapeutic intervention.

A ketogenic diet improves the prognosis in a mouse model of peritoneal dissemination without tumor regression

Peritoneal dissemination describes a state where tumor cells spread to the surface of the peritoneum and become engrafted. Peritoneal dissemination reduces the quality of life and prognosis of cancer patients. Currently, there are few effective therapies or preventative treatments for peritoneal dissemination. The aim of this study was to evaluate a ketogenic diet, characterized by high fat, moderate protein and low carbohydrate content, as a novel therapy in a mouse model of peritoneal dissemination. BALB/c mice were intraperitoneally inoculated with colon 26, a murine colon adenocarcinoma cell line, to induce experimental peritoneal dissemination. After tumor inoculation, mice were fed a regular or ketogenic diet. A longer survival time and better health status score, related to improved behavior, was observed in the ketogenic diet group compared with the regular diet group. In addition, the weight of ascites was significantly smaller and the anemia symptoms, number of red blood cell, hemoglobin and hematocrit, were improved in the ketogenic diet group compared with the regular diet group. However, the tumor weight was not significantly smaller in the ketogenic diet group compared with the regular diet group. These data suggest that a ketogenic diet might be a potential preventive therapy for peritoneal dissemination.

Modifying a Commonly Expressed Endocytic Receptor Retargets Nanoparticles in Vivo

Nanoparticles are often targeted to receptors expressed on specific cells, but few receptors are (i) highly expressed on one cell type and (ii) involved in endocytosis. One unexplored alternative is manipulating an endocytic gene expressed on multiple cell types; an ideal gene would inhibit delivery to cell type A more than cell type B, promoting delivery to cell type B. This would require a commonly expressed endocytic gene to alter nanoparticle delivery in a cell type-dependent manner in vivo; whether this can occur is unknown. Based on its microenvironmental regulation, we hypothesized Caveolin 1 (Cav1) would exert cell type-specific effects on nanoparticle delivery. Fluorescence was not sensitive enough to investigate this question, and as a result, we designed a platform named QUANT to study nanoparticle biodistribution. QUANT is 108× more sensitive than fluorescence and can be multiplexed. By measuring how 226 lipid nanoparticles (LNPs) delivered nucleic acids to multiple cell types in vivo in wild-type and Cav1 knockout mice, we found Cav1 altered delivery in a cell-type specific manner. Cav1 knockout did not alter LNP delivery to lung and kidney macrophages but substantially reduced LNP delivery to Kupffer cells, which are liver-resident macrophages. These data suggest caveolin-mediated endocytosis of nanomedicines by macrophages varies with tissue type. These results suggest manipulating receptors expressed on multiple cell types can tune drug delivery.

Metformin Inhibits Migration and Invasion by Suppressing ROS Production and COX2 Expression in MDA-MB-231 Breast Cancer Cells

Background: Several mechanisms of action have been proposed to explain the apparent antineoplastic functions of metformin, many of which are observed at high concentrations that may not be reflective of achievable tissue concentrations. We propose that metformin at low concentrations functions to inhibit ROS production and inflammatory signaling in breast cancer, thereby reducing metastasis. Methods: Using the highly invasive MDA-MB-231 breast carcinoma model, we ascertained the impact of metformin on cell viability by DNA content analysis and fluorescent dye exclusion. Migration and invasion assays were performed using a modified Boyden chamber assay and metastasis was ascertained using the chorioallantoic membrane (CAM) assay. PGE2 production was measured by Enzyme-Linked Immunosorbent Assay (ELISA). COX2 and ICAM1 levels were determined by flow cytometry immunoassay. Results: Metformin acutely decreased cell viability and caused G2 cell cycle arrest only at high concentrations (10 mM). At 100 µM, however, metformin reduced ICAM1 and COX2 expression, as well as reduced PGE2 production and endogenous mitochondrial ROS production while failing to significantly impact cell viability. Consequently, metformin inhibited migration, invasion in vitro and PGE2-dependent metastasis in CAM assays. Conclusion: At pharmacologically achievable concentrations, metformin does not drastically impact cell viability, but inhibits inflammatory signaling and metastatic progression in breast cancer cells.

Stromal epigenetic alterations drive metabolic and neuroendocrine prostate cancer reprogramming

Prostate cancer is an androgen-dependent disease subject to interactions between the tumor epithelium and its microenvironment. Here, we found that epigenetic changes in prostatic cancer-associated fibroblasts (CAF) initiated a cascade of stromal-epithelial interactions. This facilitated lethal prostate cancer growth and development of resistance to androgen signaling deprivation therapy (ADT). We identified a Ras inhibitor, RASAL3, as epigenetically silenced in human prostatic CAF, leading to oncogenic Ras activity driving macropinocytosis-mediated glutamine synthesis. Interestingly, ADT further promoted RASAL3 epigenetic silencing and glutamine secretion by prostatic fibroblasts. In an orthotopic xenograft model, subsequent inhibition of macropinocytosis and glutamine transport resulted in antitumor effects. Stromal glutamine served as a source of energy through anaplerosis and as a mediator of neuroendocrine differentiation for prostate adenocarcinoma. Antagonizing the uptake of glutamine restored sensitivity to ADT in a castration-resistant xenograft model. In validating these findings, we found that prostate cancer patients on ADT with therapeutic resistance had elevated blood glutamine levels compared with those with therapeutically responsive disease (odds ratio = 7.451, P = 0.02). Identification of epigenetic regulation of Ras activity in prostatic CAF revealed RASAL3 as a sensor for metabolic and neuroendocrine reprogramming in prostate cancer patients failing ADT.

The Influence of Breast Tumour-Derived Factors and Wnt Antagonism on the Transformation of Adipose-Derived Mesenchymal Stem Cells into Tumour-Associated Fibroblasts

Within the tumour stroma, a heterogeneous population of cell types reciprocally regulates cell proliferation, which considerably affects the progression of the disease. In this study, using tumour conditioned medium (TCM) derived from breast tumour cell lines - MCF7 and MDA MB 231, we have demonstrated the differentiation of adipose-derived mesenchymal stem cells (ADSCs) into tumour-associated fibroblasts (TAFs). Since the Wnt signalling pathway is a key signalling pathway driving breast tumour growth, the effect of the Wnt antagonist secreted frizzled-related protein 4 (sFRP4) was also examined. The response of ADSCs to TCM and sFRP4 treatments was determined by using cell viability assay to determine the changes in ADSC viability, immunofluorescence for mesenchymal markers, glucose uptake assay, and glycolysis stress test using the Seahorse Extracellular Flux analyser to determine the glycolytic activity of ADSCs. ADSCs have been shown to acquire a hyper-proliferative state, significantly increasing their number upon short-term and long-term exposure to TCM. Changes have also been observed in the expression of key mesenchymal markers as well as in the metabolic state of ADSCs. SFRP4 significantly inhibited the differentiation of ADSCs into TAFs by reducing cell growth as well as mesenchymal marker expression (cell line-dependent). However, sFRP4 did not induce further significant changes to the altered metabolic phenotype of ADSCs following TCM exposure. Altogether, this study suggests that the breast tumour milieu may transform ADSCs into a tumour-supportive phenotype, which can be altered by Wnt antagonism, but is independent of metabolic changes.

MiR-21-mediated Metabolic Alteration of Cancer-associated Fibroblasts and Its Effect on Pancreatic Cancer Cell Behavior

In this study, we investigated whether the metabolic alteration of cancer-associated fibroblasts (CAFs) occurs via miR-21 remodeling and the effect of this alteration on pancreatic cancer cells. CAFs and normal fibroblasts (NFs) were isolated and cultured. Glucose consumption and lactic acid production were tested, and lactate dehydrogenase (LDHA), pyruvate kinase m2 (PKM2), and miR-21 expression were examined. The level of glycolysis in CAFs was determined after treatment with a miR-21 inhibitor. Primary miR-21-NC CAFs and miR-21-inhibitor CAFs were indirectly co-cultured with BxPc-3 in vitro, and the invasion capacity of these cells was determined. The aerobic oxidation index of cancer cells and the expression of succinodehydrogenase (SDH) and fumarate hydratase (FH) were assessed. Compared with NFs, CAFs showed enhanced glucose uptake capacity, lactic acid production, and elevated LDHA, PKM2, and miR-21 expression. After miR-21 inhibitor treatment, the extent of glycolysis in CAFs was reduced. After indirect co-culture with CAFs, oxidative phosphorylation and SDH, FH, and MCT expression increased in BxPc-3 cells. After co-culture with miR-21-inhibitor-CAFs, oxidative phosphorylation and invasion ability of the pancreatic cancer cells decreased. MiR-21 was involved in metabolic alteration of CAFs and affected the development of cancer cells. This metabolic alteration may be an important mechanism by which the microenvironment promotes tumor progression in a nonvascular manner.

The Warburg effect: 80 years on

Influential research by Warburg and Cori in the 1920s ignited interest in how cancer cells' energy generation is different from that of normal cells. They observed high glucose consumption and large amounts of lactate excretion from cancer cells compared with normal cells, which oxidised glucose using mitochondria. It was therefore assumed that cancer cells were generating energy using glycolysis rather than mitochondrial oxidative phosphorylation, and that the mitochondria were dysfunctional. Advances in research techniques since then have shown the mitochondria in cancer cells to be functional across a range of tumour types. However, different tumour populations have different bioenergetic alterations in order to meet their high energy requirement; the Warburg effect is not consistent across all cancer types. This review will discuss the metabolic reprogramming of cancer, possible explanations for the high glucose consumption in cancer cells observed by Warburg, and suggest key experimental practices we should consider when studying the metabolism of cancer.