Omega 3 fatty acids chemosensitize multidrug resistant colon cancer cells by down-regulating cholesterol synthesis and altering detergent resistant membranes composition

Does the ratio of eicosapentaenoic acid to docosahexaenoic acid matter in cancer treatment? A systematic review of their effects on cachexia-related inflammation

Chronic inflammation is a hallmark of cancer cachexia. Polyunsaturated fatty acids (ω-3 PUFAs): eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are known to contribute to the reduction of inflammation, preservation of lean body mass and total body weight, and reduction of cancer-related symptoms, such as anorexia or neuropathy. This systematic review aimed to assess whether the ratio of EPA to DHA used in supplementation in cancer patients matters in the context of the resolution of inflammation and reduction of the risk of cachexia. The analysis included 20 randomized clinical trials with acceptable quality identified from the Pubmed/MEDLINE database. The significant results concerning the resolution of inflammation or improvement in nutritional status were the highest in the case of a low EPA/DHA ratio, i.e., 67%, and decreased, reaching 50% and 36% for the moderate and high ratios, respectively. Most results concerning body weight from high and moderate EPA/DHA ratios showed no benefit or were insignificant. A significant benefit in reducing any reported inflammatory markers was seen in the low EPA/DHA ratio subgroup at 63%, in the moderate at 29%, and in the high ratio subgroup at 11%. The greatest benefit in CRP reduction was obtained by patients during chemotherapy. The review questions the anticachectic and anti-inflammatory effect of ω-3 PUFAs supplementation with doses of EPA higher than DHA. A population that particularly benefits from ω-3 PUFAs supplementation are patients undergoing chemotherapy for advanced cancer.

Molecular Mechanisms Associated with the Inhibitory Role of Long Chain n-3 PUFA in Colorectal Cancer

Colorectal cancer (CRC) is the third leading cause of cancer-related death in the world. Multiple evidence suggests that there is an association between excess fat consumption and the risk of CRC. The long chain n-3 polyunsaturated fatty acids (LC n-3 PUFA), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are essential for human health, and both in vitro and in vivo studies have shown that these fatty acids can prevent CRC development through various molecular mechanisms. These include the modulation of arachidonic acid (AA) derived prostaglandin synthesis, alteration of growth signaling pathways, arrest of the cell cycle, induction of cell apoptosis, suppression of angiogenesis and modulation of inflammatory response. Human clinical studies found that LC n-3 PUFA combined with chemotherapeutic agents can improve the efficacy of treatment and reduce the dosage of chemotherapy and associated side effects. In this review, we discuss comprehensively the anti-cancer effects of LC n-3 PUFA on CRC, with a main focus on the underlying molecular mechanisms.

p140Cap modulates the mevalonate pathway decreasing cell migration and enhancing drug sensitivity in breast cancer cells

p140Cap is an adaptor protein involved in assembling multi-protein complexes regulating several cellular processes. p140Cap acts as a tumor suppressor in breast cancer (BC) and neuroblastoma patients, where its expression correlates with a better prognosis. The role of p140Cap in tumor metabolism remains largely unknown. Here we study the role of p140Cap in the modulation of the mevalonate (MVA) pathway in BC cells. The MVA pathway is responsible for the biosynthesis of cholesterol and non-sterol isoprenoids and is often deregulated in cancer. We found that both in vitro and in vivo, p140Cap cells and tumors show an increased flux through the MVA pathway by positively regulating the pace-maker enzyme of the MVA pathway, the 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR), via transcriptional and post-translational mechanisms. The higher cholesterol synthesis is paralleled with enhanced cholesterol efflux. Moreover, p140Cap promotes increased cholesterol localization in the plasma membrane and reduces lipid rafts-associated Rac1 signalling, impairing cell membrane fluidity and cell migration in a cholesterol-dependent manner. Finally, p140Cap BC cells exhibit decreased cell viability upon treatments with statins, alone or in combination with chemotherapeutic at low concentrations in a synergistic manner. Overall, our data highlight a new perspective point on tumor suppression in BC by establishing a previously uncharacterized role of the MVA pathway in p140Cap expressing tumors, thus paving the way to the use of p140Cap as a potent biomarker to stratify patients for better tuning therapeutic options.

Glucose increases proliferation and chemoresistance in chronic myeloid leukemia via decreasing antioxidant Properties of ω-3 polyunsaturated fatty acids in the presence of Iron

BACKGROUND

There is a strong association between hyperglycemia, oxidative stress, inflammation and the onset and progression of diabetes which causes a higher risk of cancer. This study investigated, the effect of concomitant use of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) with iron supplements in hyper-glucose conditions on the K-562 cell line.

METHODS

The effects of iron, ω-3 PUFAs, and a combination of both on K-562 cells were investigated under normal and high glucose conditions. The impact of these treatments was evaluated using multiple methodologies, including the MTT assay for cell viability, quantification of oxidative stress markers [total antioxidant capacity (TAC) and malondialdehyde (MDA)], and analysis of the cell cycle. Furthermore, the expression levels of TNFα and p53 mRNA were measured using Real-time PCR.

RESULTS

The co-treatment of ω-3 PUFAs and iron in the presence of high glucose had notable effects, as evidenced by an increase in cell survival, resistance to imatinib chemotherapy, TNFαmRNA expression levels, MDA levels, and percentage of cells in the G2/S phase. Additionally, there was a decrease in the mRNA expression of p53 and TAC levels compared to treatment in the normal-glucose condition.

CONCLUSION

Hyperglycemic conditions in conjunction with the combined treatment of theω-3 PUFAs and iron, led to reduced anticancer capacity, chemosensitivity, anti-inflammatory and antioxidant properties of the K-562 cells. These effects were found to be mediated by oxidative stress.

Targeting dysregulated lipid metabolism in the tumor microenvironment

The reprogramming of lipid metabolism and its association with oncogenic signaling pathways within the tumor microenvironment (TME) have emerged as significant hallmarks of cancer. Lipid metabolism is defined as a complex set of molecular processes including lipid uptake, synthesis, transport, and degradation. The dysregulation of lipid metabolism is affected by enzymes and signaling molecules directly or indirectly involved in the lipid metabolic process. Regulation of lipid metabolizing enzymes has been shown to modulate cancer development and to avoid resistance to anticancer drugs in tumors and the TME. Because of this, understanding the metabolic reprogramming associated with oncogenic progression is important to develop strategies for cancer treatment. Recent advances provide insight into fundamental mechanisms and the connections between altered lipid metabolism and tumorigenesis. In this review, we explore alterations to lipid metabolism and the pivotal factors driving lipid metabolic reprogramming, which exacerbate cancer progression. We also shed light on the latest insights and current therapeutic approaches based on small molecular inhibitors and phytochemicals targeting lipid metabolism for cancer treatment. Further investigations are worthwhile to fully understand the underlying mechanisms and the correlation between altered lipid metabolism and carcinogenesis.

Cholesterol-Depletion-Induced Membrane Repair Carries a Raft Conformer of P-Glycoprotein to the Cell Surface, Indicating Enhanced Cholesterol Trafficking in MDR Cells, Which Makes Them Resistant to Cholesterol Modifications

The human P-glycoprotein (P-gp), a transporter responsible for multidrug resistance, is present in the plasma membrane's raft and non-raft domains. One specific conformation of P-gp that binds to the monoclonal antibody UIC2 is primarily associated with raft domains and displays heightened internalization in cells overexpressing P-gp, such as in NIH-3T3 MDR1 cells. Our primary objective was to investigate whether the trafficking of this particular P-gp conformer is dependent on cholesterol levels. Surprisingly, depleting cholesterol using cyclodextrin resulted in an unexpected increase in the proportion of raft-associated P-gp within the cell membrane, as determined by UIC2-reactive P-gp. This increase appears to be a compensatory response to cholesterol loss from the plasma membrane, whereby cholesterol-rich raft micro-domains are delivered to the cell surface through an augmented exocytosis process. Furthermore, this exocytotic event is found to be part of a complex trafficking mechanism involving lysosomal exocytosis, which contributes to membrane repair after cholesterol reduction induced by cyclodextrin treatment. Notably, cells overexpressing P-gp demonstrated higher total cellular cholesterol levels, an increased abundance of stable lysosomes, and more effective membrane repair following cholesterol modifications. These modifications encompassed exocytotic events that involved the transport of P-gp-carrying rafts. Importantly, the enhanced membrane repair capability resulted in a durable phenotype for MDR1 expressing cells, as evidenced by significantly improved viabilities of multidrug-resistant Pgp-overexpressing immortal NIH-3T3 MDR1 and MDCK-MDR1 cells compared to their parents when subjected to cholesterol alterations.

Effect of Polyunsaturated Fatty Acids on Temozolomide Drug-Sensitive and Drug-Resistant Glioblastoma Cells

Glioblastomas (GBMs) are notoriously difficult to treat, and the development of multiple drug resistance (MDR) is common during the course of the disease. The polyunsaturated fatty acids (PUFAs) gamma-linolenic acid (GLA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) have been reported to improve MDR in several tumors including breast, bladder, and leukaemia. However, the effects of PUFAs on GBM cell MDR are poorly understood. The present study investigated the effects of PUFAs on cellular responses to temozolomide (TMZ) in U87MG cells and the TMZ-resistant (TMZR) cells derived from U87MG. Cells were treated with PUFAs in the absence or presence of TMZ and dose–response, viable cell counting, gene expression, Western blotting, flow cytometry, gas chromatography-mass spectrometry (GCMS), and drug efflux studies were performed. The development of TMZ resistance caused an increase in ABC transporter ABCB1 and ABCC1 expression. GLA-, EPA-, and DHA-treated cells had altered fatty acid composition and accumulated lipid droplets in the cytoplasm. The most significant reduction in cell growth was seen for the U87MG and TMZR cells in the presence of EPA. GLA and EPA caused more significant effects on ABC transporter expression than DHA. GLA and EPA in combination with TMZ caused significant reductions in rhodamine 123 efflux from U87MG cells but not from TMZR cells. Overall, these findings support the notion that PUFAs can modulate ABC transporters in GBM cells.

Distinct effects of α-linolenic acid and docosahexaenoic acid on the expression of genes related to cholesterol metabolism and the response to infection in THP-1 monocytes and immune cells of obese humans

BACKGROUND

Monocytes play a large role in chronic inflammatory conditions such as obesity, atherosclerosis and infection. Marine-derived omega-3 fatty acids such as docosahexaenoic acid (DHA) beneficially alter immune function and attenuate chronic inflammation in part by modifying gene expression. Comparisons with plant-derived omega-3 α-linolenic acid (ALA) on immune cell gene expression and function are limited.

METHODS

Transcriptome analysis was performed on THP-1 human monocytes treated with ALA, DHA or vehicle for 48 hr using fold change analysis, principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA), variable importance analysis (VIP), and ingenuity pathway analysis (IPA). Candidate genes were validated by qPCR. Functional assays evaluated the transcriptomic predictions. Expression of candidate transcripts identified in THP-1 cells were examined in PBMC from clinical trial (OXBIO; NCT03583281) participants consuming ALA- or DHA-rich oil supplements.

FINDINGS

ALA and DHA-treated monocytes presented distinct transcriptomic profiles as per VIP and PLS-DA. Both fatty acids were predicted to reduce cellular cholesterol content, while ALA would uniquely increase response to infection and chemotactic signals. Functional assays revealed ALA and DHA decreased cholesterol content. DHA significantly decreased the response to infection and chemotaxis, but ALA had no effect. Candidate transcripts responded similarly in PBMC from n-3 PUFA supplemented women with obesity.

CONCLUSION

ALA and DHA differentially alter the transcription profiles and functions associated with the response to infection, chemotaxis, and cholesterol metabolism in mononuclear immune cells. Thus, they may uniquely affect related disease processes contributing to obesity, atherosclerosis, and the response to infection.

Protein degradation: expanding the toolbox to restrain cancer drug resistance

Despite significant progress in clinical management, drug resistance remains a major obstacle. Recent research based on protein degradation to restrain drug resistance has attracted wide attention, and several therapeutic strategies such as inhibition of proteasome with bortezomib and proteolysis-targeting chimeric have been developed. Compared with intervention at the transcriptional level, targeting the degradation process seems to be a more rapid and direct strategy. Proteasomal proteolysis and lysosomal proteolysis are the most critical quality control systems responsible for the degradation of proteins or organelles. Although proteasomal and lysosomal inhibitors (e.g., bortezomib and chloroquine) have achieved certain improvements in some clinical application scenarios, their routine application in practice is still a long way off, which is due to the lack of precise targeting capabilities and inevitable side effects. In-depth studies on the regulatory mechanism of critical protein degradation regulators, including E3 ubiquitin ligases, deubiquitylating enzymes (DUBs), and chaperones, are expected to provide precise clues for developing targeting strategies and reducing side effects. Here, we discuss the underlying mechanisms of protein degradation in regulating drug efflux, drug metabolism, DNA repair, drug target alteration, downstream bypass signaling, sustaining of stemness, and tumor microenvironment remodeling to delineate the functional roles of protein degradation in drug resistance. We also highlight specific E3 ligases, DUBs, and chaperones, discussing possible strategies modulating protein degradation to target cancer drug resistance. A systematic summary of the molecular basis by which protein degradation regulates tumor drug resistance will help facilitate the development of appropriate clinical strategies.

Identification of Prognostic Fatty Acid Metabolism lncRNAs and Potential Molecular Targeting Drugs in Uveal Melanoma

Background

The aim of this study was to identify prognostic fatty acid metabolism lncRNAs and potential molecular targeting drugs in uveal melanoma through integrated bioinformatics analysis.

Methods

In the present study, we obtained the expression matrix of 309 FAM-mRNAs and identified 225 FAM-lncRNAs by coexpression network analysis. We then performed univariate Cox analysis, LASSO regression analysis, and cross-validation and finally obtained an optimized UVM prognosis prediction model composed of four PFAM-lncRNAs (AC104129.1, SOS1-IT1, IDI2-AS1, and DLGAP1-AS2).

Results

The survival curves showed that the survival time of UVM patients in the high-risk group was significantly lower than that in the low-risk group in the train cohort, test cohort, and all patients in the prognostic prediction model (P < 0.05). We further performed risk prognostic assessment, and the results showed that the risk scores of the high-risk group in the train cohort, test cohort, and all patients were significantly higher than those of the low-risk group (P < 0.05), patient survival decreased and the number of deaths increased with increasing risk scores, and AC104129.1, SOS1-IT1, and DLGAP1-AS2 were high-risk PFAM-lncRNAs, while IDI2-AS1 were low-risk PFAM-lncRNAs. Afterwards, we further verified the accuracy and the prognostic value of our model in predicting prognosis by PCA analysis and ROC curves.

Conclusion

We identified 24 potential molecularly targeted drugs with significant sensitivity differences between high- and low-risk UVM patients, of which 13 may be potential targeted drugs for high-risk patients. Our findings have important implications for early prediction and early clinical intervention in high-risk UVM patients.

Posttranslational control of lipogenesis in the tumor microenvironment

Metabolic reprogramming of cancer cells within the tumor microenvironment typically occurs in response to increased nutritional, translation and proliferative demands. Altered lipid metabolism is a marker of tumor progression that is frequently observed in aggressive tumors with poor prognosis. Underlying these abnormal metabolic behaviors are posttranslational modifications (PTMs) of lipid metabolism-related enzymes and other factors that can impact their activity and/or subcellular localization. This review focuses on the roles of these PTMs and specifically on how they permit the re-wiring of cancer lipid metabolism, particularly within the context of the tumor microenvironment.

Multi-omics characterization of the unsaturated fatty acid biosynthesis pathway in colon cancer

The biosynthesis of unsaturated fatty acids is involved in the initiation and progression of colon adenocarcinoma (COAD). In this study, we aimed to investigate the multi-omics characteristics of unsaturated fatty acid biosynthesis-related genes and explore their prognostic value in colon cancer by analyzing the data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. An unsaturated fatty acid biosynthesis pathway related-genes enrichment score (BUFAS) was constructed utilizing the single sample gene set enrichment analysis (ssGSEA). We discovered that a high BUFAS was associated with longer overall survival (OS) in both the training and the validation sets. Multivariable analysis including the clinical characteristics further verified the independent prognostic value of the BUFAS in both the TCGA-COAD and the GSE39582 datasets. In addition, GSEA analysis revealed that BUFAS was positively associated with several signaling pathways, including MTORC1, peroxisome, and pathways related to fatty acid metabolism, while was negatively associated with other signaling pathways, such as hedgehog, NOTCH, and Wnt/beta-catenin pathway. Furthermore, in the COAD cell lines of the Genomics of Drug Sensitivity in Cancer (GDSC) database, we found that BUFAS was positively correlated with the drug sensitivities of cisplatin, gemcitabine, camptothecin, lapatinib, and afatinib, while was negatively correlated with that of ponatinib. Moreover, in the COAD single-cell transcriptomic dataset (GSE146771), the BUFAS varied among different cell types and was enriched in mast cells and fibroblasts. Taken together, the BUFAS we constructed could be used as an independent prognostic signature in predicting the OS and drug resistance of colon cancer. Unsaturated fatty acid biosynthesis pathway might serve as potential therapeutic targets for cancer treatment.

Cholesterol and Its Derivatives: Multifaceted Players in Breast Cancer Progression

Cholesterol is an essential lipid primarily synthesized in the liver through the mevalonate pathway. Besides being a precursor of steroid hormones, bile acid, and vitamin D, it is an essential structural component of cell membranes, is enriched in membrane lipid rafts, and plays a key role in intracellular signal transduction. The lipid homeostasis is finely regulated end appears to be impaired in several types of tumors, including breast cancer. In this review, we will analyse the multifaceted roles of cholesterol and its derivatives in breast cancer progression. As an example of the bivalent role of cholesterol in the cell membrane of cancer cells, on the one hand, it reduces membrane fluidity, which has been associated with a more aggressive tumor phenotype in terms of cell motility and migration, leading to metastasis formation. On the other hand, it makes the membrane less permeable to small water-soluble molecules that would otherwise freely cross, resulting in a loss of chemotherapeutics permeability. Regarding cholesterol derivatives, a lower vitamin D is associated with an increased risk of breast cancer, while steroid hormones, coupled with the overexpression of their receptors, play a crucial role in breast cancer progression. Despite the role of cholesterol and derivatives molecules in breast cancer development is still controversial, the use of cholesterol targeting drugs like statins and zoledronic acid appears as a challenging promising tool for breast cancer treatment.

Regulation of Glucose, Fatty Acid and Amino Acid Metabolism by Ubiquitination and SUMOylation for Cancer Progression

Ubiquitination and SUMOylation, which are posttranslational modifications, play prominent roles in regulating both protein expression and function in cells, as well as various cellular signal transduction pathways. Metabolic reprogramming often occurs in various diseases, especially cancer, which has become a new entry point for understanding cancer mechanisms and developing treatment methods. Ubiquitination or SUMOylation of protein substrates determines the fate of modified proteins. Through accurate and timely degradation and stabilization of the substrate, ubiquitination and SUMOylation widely control various crucial pathways and different proteins involved in cancer metabolic reprogramming. An understanding of the regulatory mechanisms of ubiquitination and SUMOylation of cell proteins may help us elucidate the molecular mechanism underlying cancer development and provide an important theory for new treatments. In this review, we summarize the processes of ubiquitination and SUMOylation and discuss how ubiquitination and SUMOylation affect cancer metabolism by regulating the key enzymes in the metabolic pathway, including glucose, lipid and amino acid metabolism, to finally reshape cancer metabolism.

Impact of cancer metabolism on therapy resistance - Clinical implications

Despite an increasing arsenal of anticancer therapies, many patients continue to have poor outcomes due to the therapeutic failures and tumor relapses. Indeed, the clinical efficacy of anticancer therapies is markedly limited by intrinsic and/or acquired resistance mechanisms that can occur in any tumor type and with any treatment. Thus, there is an urgent clinical need to implement fundamental changes in the tumor treatment paradigm by the development of new experimental strategies that can help to predict the occurrence of clinical drug resistance and to identify alternative therapeutic options. Apart from mutation-driven resistance mechanisms, tumor microenvironment (TME) conditions generate an intratumoral phenotypic heterogeneity that supports disease progression and dismal outcomes. Tumor cell metabolism is a prototypical example of dynamic, heterogeneous, and adaptive phenotypic trait, resulting from the combination of intrinsic [(epi)genetic changes, tissue of origin and differentiation dependency] and extrinsic (oxygen and nutrient availability, metabolic interactions within the TME) factors, enabling cancer cells to survive, metastasize and develop resistance to anticancer therapies. In this review, we summarize the current knowledge regarding metabolism-based mechanisms conferring adaptive resistance to chemo-, radio-and immunotherapies as well as targeted therapies. Furthermore, we report the role of TME-mediated intratumoral metabolic heterogeneity in therapy resistance and how adaptations in amino acid, glucose, and lipid metabolism support the growth of therapy-resistant cancers and/or cellular subpopulations. We also report the intricate interplay between tumor signaling and metabolic pathways in cancer cells and discuss how manipulating key metabolic enzymes and/or providing dietary changes may help to eradicate relapse-sustaining cancer cells. Finally, in the current era of personalized medicine, we describe the strategies that may be applied to implement metabolic profiling for tumor imaging, biomarker identification, selection of tailored treatments and monitoring therapy response during the clinical management of cancer patients.

Hypoxia as a driver of resistance to immunotherapy

Hypoxia, a hallmark of solid tumors, determines the selection of invasive and aggressive malignant clones displaying resistance to radiotherapy, conventional chemotherapy or targeted therapy. The recent introduction of immunotherapy, based on immune checkpoint inhibitors (ICPIs) and chimeric antigen receptor (CAR) T-cells, has markedly transformed the prognosis in some tumors but also revealed the existence of intrinsic or acquired drug resistance. In the current review we highlight hypoxia as a culprit of immunotherapy failure. Indeed, multiple metabolic cross talks between tumor and stromal cells determine the prevalence of immunosuppressive populations within the hypoxic tumor microenvironment and confer upon tumor cells resistance to ICPIs and CAR T-cells. Notably, hypoxia-triggered angiogenesis causes immunosuppression, adding another piece to the puzzle of hypoxia-induced immunoresistance. If these factors concurrently contribute to the resistance to immunotherapy, they also unveil an unexpected Achille's heel of hypoxic tumors, providing the basis for innovative combination therapies that may rescue the efficacy of ICPIs and CAR T-cells. Although these treatments reveal both a bright side and a dark side in terms of efficacy and safety in clinical trials, they represent the future solution to enhance the efficacy of immunotherapy against hypoxic and therapy-resistant solid tumors.

Effect of omega-3 fatty acids supplementation on cardio-metabolic and oxidative stress parameters in patients with chronic kidney disease: a systematic review and meta-analysis

Background

Omega-3 fatty acids (FAs) have been suggested as a beneficial supplement in chronic kidney disease (CKD) patients, but the results of randomized clinical trials (RCTs) are controversial. We conducted a systematic review and meta-analysis to evaluate all the RCTs about the impact of omega-3 FAs supplementation on cardiometabolic outcomes and oxidative stress parameters in patients with CKD.

Methods

We performed a systematic database search in PubMed/MEDLINE, EMBASE, Scopus, Web of Science, and Cochrane Central, up to May 2020. We included all placebo-controlled randomized trials that assessed the effect of omega-3 FAs supplementation on any cardiometabolic outcomes: blood pressure, total cholesterol (TC), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) or triglycerides (TG) and oxidative stress parameters. Data were pooled using DerSimonian–Laird’s random-effects model.

Results

Finally, thirteen articles met the inclusion criteria for this review omega-3 FAs supplementation significantly decrease TC (SMD: -0.26; 95% CI: − 0.51, − 0.02; I² = 52.7%), TG (SMD: -0.22; 95% CI: − 0.43, − 0.02; I² = 36.0%) and Malondialdehyde (MDA) levels (SMD: -0.91; 95% CI: − 1.29, − 0.54; I² = 00.0%) and also significantly increase superoxide dismutase (SOD) (SMD: 0.58; 95% CI: 0.27, 0.90; I² = 00.0%) and Glutathione peroxidase (GPx) (SMD: 0.50; 95% CI: 0.14, 0.86; I² = 00.0%) activities. However our results show that omega-3 FAs supplementation have no significant effects on HDL, LDL and blood pressure.

Conclusion

This systematic review and meta-analysis supports current evidence for the clinical benefit of omega-3 FAs intake to improve cardiometabolic parameters in CKD patients. However, well-designed RCTs still needed to provide a conclusive picture in this field.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02351-9.

E3 Ubiquitin Ligase in Anticancer Drugdsla Resistance: Recent Advances and Future Potential

Drug therapy is the primary treatment for patients with advanced cancer. The use of anticancer drugs will inevitably lead to drug resistance, which manifests as tumor recurrence. Overcoming chemoresistance may enable cancer patients to have better therapeutic effects. However, the mechanisms underlying drug resistance are poorly understood. E3 ubiquitin ligases (E3s) are a large class of proteins, and there are over 800 putative functional E3s. E3s play a crucial role in substrate recognition and catalyze the final step of ubiquitin transfer to specific substrate proteins. The diversity of the set of substrates contributes to the diverse functions of E3s, indicating that E3s could be desirable drug targets. The E3s MDM2, FBWX7, and SKP2 have been well studied and have shown a relationship with drug resistance. Strategies targeting E3s to combat drug resistance include interfering with their activators, degrading the E3s themselves and influencing the interaction between E3s and their substrates. Research on E3s has led to the discovery of possible therapeutic methods to overcome the challenging clinical situation imposed by drug resistance. In this article, we summarize the role of E3s in cancer drug resistance from the perspective of drug class.

Functional Doxorubicin-Loaded Omega-3 Unsaturated Fatty Acids Nanoparticles in Reversing Hepatocellular Carcinoma Multidrug Resistance

Background

This study investigated a nanoparticle drug delivery system to reverse multidrug resistance (MDR) and assessed its anticancer efficacy in hepatocellular carcinoma (HCC).

Material/Methods

Docosahexaenoic acid (DHA) was used as the functional excipient and doxorubicin (DOX) as the chemotherapeutic drug to synthesize DOX nanoparticles (DOX-nano). The human HCC cell line HepG2 was used for experiments. HepG2/DOX, HepG2+DOX, HepG2+DOX-nano, HepG2/DOX+DOX, and HepG2/DOX+DOX-nano groups cells were treated with DOX or DOX-nano (5 μg/mL). Nude mice bearing a HepG2/DOX xenograft were divided into model, DOX, vector-nano, and DOX-nano groups and injected with saline, DOX reagent, vector-nano, and DOX-nano (2 mg/kg), respectively. Next, cytotoxicity, cellular uptake, cell apoptosis and migration, fluorescence imaging, TUNEL assay, and tumor inhibition effects were assessed in vitro and in vivo. Furthermore, expression of MDR-related proteins was also detected using western blotting.

Results

Fluorescence imaging showed that the DOX uptake in the DOX-nano-treated group was the strongest in the HCC cells or tumors. Cell apoptosis was significantly increased in DOX-nano-treated HepG2/DOX cells and tumors, and cell migration was significantly inhibited in the DOX-nano-treated HepG2/DOX cells compared with the other groups. The tumor inhibitory rate in DOX-nano-injected tumors was also significantly higher than in other groups. The expression of breast cancer resistance protein, B-cell lymphoma 2, lung resistance protein, multidrug resistance protein, and protein kinase C alpha was significantly decreased in DOX-nano-treated HepG2/DOX cells and xenograft tumors. Significantly better antitumor and MDR-reversing effects were also observed in the HepG2+DOX group compared with the HepG2/DOX group.

Conclusions

This study revealed the potential efficacy of a DOX-nano drug delivery system for the treatment of HCC, using HepG2/DOX cells and nude mice bearing HepG2/DOX xenografts.

Elucidation of underlying molecular mechanism of 5-Fluorouracil chemoresistance and its restoration using fish oil in experimental colon carcinoma

Latest strategies for cancer treatment primarily focus on the use of chemosensitizers to enhance therapeutic outcome. N-3 PUFAs have emerged as the strongest candidate for the prevention of colorectal cancer (CRC). Our previous studies have demonstrated that fish oil (FO) rich in n-3 PUFAs not only increased therapeutic potential of 5-Fluorouracil(5-FU) in colon cancer but also ameliorated its toxicity. Henceforth, the present study is designed to elucidate mechanistic insights of FO as a chemosensitizer to circumvent drug resistance in experimental colon carcinoma. The colon cancer was induced by 1,2-dimethylhydrazine(DMH)/dextran sulfate sodium(DSS) in male Balb/c mice and these animals were treated with 5-FU(12.5 mg/kg b.w.), FO(0.2 ml), or 5-FU + FO(12.5 mg/kg b.w + 0.2 ml) orally for 14 days. The molecular mechanism of overcoming 5-FU resistance using FO in colon cancer was delineated by estimating expression of cancer stem cell markers using flowcytometric method and drug transporters by immunohistochemistry and immunoblotting. Additionally, distribution profile of 5-FU and its cytotoxic metabolite, 5-FdUMP at target(colon), and non-target sites (serum, kidney, liver, spleen) was assessed using high-performance liquid chromatography(HPLC) method. The observations revealed that expression of CSCs markers was remarkably reduced after using fish oil along with 5-FU in carcinogen-treated animals. Interestingly, the use of FO alongwith 5-FU also significantly declined the expression of drug transporters (ABCB1,ABCC5) and consequently resulted in an increased cellular uptake of 5-FU and its metabolite, 5-FdUMP at target site (colon). It could be possibly associated with change in permeability of cell membrane owing to the alteration in membrane fluidity. The present study revealed the mechanistic insights of FO as a MDR revertant which successfully restored 5-FU-mediated chemoresistance in experimental colon carcinoma.

Omega-3 fatty acids ameliorate doxorubicin-induced cardiorenal toxicity: In-vivo regulation of oxidative stress, apoptosis and renal Nox4, and in-vitro preservation of the cytotoxic efficacy

This study examines the protective effects of omega-3 fatty acids (OMG), a frequently used nutritional therapy in cancer patients, against doxorubicin (DOX)-induced acute cardiorenal toxicity in rats, and evaluates the cytotoxic activity of DOX when used with OMG against breast cancer cell line. Five groups of rats were treated for 4 consecutive weeks with vehicle (groups I & II), or OMG (25, 50 or 100 mg/kg/day, po; groups III, IV & V, respectively). After twenty-four hours, the last four groups were injected with DOX (200 mg/kg, ip). In DOX-treated rats, the altered ECG, serum cardiac and renal function biomarkers, and histopathological features indicated the induction of cardiorenal toxicity. Increased oxidative and apoptotic markers in both organs was observed, with elevated renal contents of NADPH-oxidase-4 (Nox4) and renin. OMG pretreatment improved those DOX-induced impairments in a dose-dependent manner, and showed antioxidant and antiapoptotic effects with regulation of renal Nox4 expression. The in-vitro study showed preservation of the cytotoxic activity of DOX on MCF7 cell line in the presence of OMG. The data suggests OMG for protection against acute DOX-induced cardiorenal damage without affecting the latter antitumor activity. It proposes regulation of oxidative stress, Nox4 activity and apoptosis as contributing protective mechanisms.

Inhibition of lovastatin- and docosahexaenoic acid-initiated autophagy in triple negative breast cancer reverted resistance and enhanced cytotoxicity

AIMS

Autophagy plays a complex role in breast cancer by suppressing or improving the efficiency of treatment. Triple-negative breast cancer (TNBC) cell line (MDA-MB-231) is associated with aggressive response and developing therapy resistance. MDA-MB-231 cells depend on autophagy for survival. Also, the potential benefits of autophagy inhibition in ameliorating developed chemotherapy resistance towards MDA-MB-231 remains to be elucidated. Despite showing anti-tumorigenic activities, the use of lovastatin and docosahexaenoic acid (DHA) for treating different types of cancers is still limited. We aimed to investigate the protective effect of autophagy inhibition by chloroquine (CQ) in MDA-MB-231 cells resistance treated with lovastatin or DHA.

MAIN METHODS

MDA-MB-231 cells were treated with 30 μM lovastatin and/or 100 μM DHA for 48 h plus 20 μM CQ. Autophagic flux was assessed in association with the expression of multidrug resistance gene 1 (MDR1), transforming growth factor beta 1 gene (TGF-β1), and autophagy-related 7 gene (ATG7).

KEY FINDINGS

Both drugs exhibited dose-dependent cytotoxicity, enhanced the autophagic flux represented by increased LC3BII protein concentration and decreased p62 protein concentration, and up-regulated the expression of MDR1, TGF-β1, and ATG7 genes. CQ addition enhanced the cytotoxicity of drugs and inhibited the autophagic flux which is detected by higher levels of LC3BII and p62 correlated with the reverted MDR1, TGF-β1 and ATG7 genes expression.

SIGNIFICANCE

Autophagy inhibition by CQ showed an ameliorative effect on lovastatin- and DHA-induced resistance and enhanced their cytotoxicity, providing a promising strategy in breast cancer therapy.

The role of ubiquitination and deubiquitination in cancer metabolism

Metabolic reprogramming, including enhanced biosynthesis of macromolecules, altered energy metabolism, and maintenance of redox homeostasis, is considered a hallmark of cancer, sustaining cancer cell growth. Multiple signaling pathways, transcription factors and metabolic enzymes participate in the modulation of cancer metabolism and thus, metabolic reprogramming is a highly complex process. Recent studies have observed that ubiquitination and deubiquitination are involved in the regulation of metabolic reprogramming in cancer cells. As one of the most important type of post-translational modifications, ubiquitination is a multistep enzymatic process, involved in diverse cellular biological activities. Dysregulation of ubiquitination and deubiquitination contributes to various disease, including cancer. Here, we discuss the role of ubiquitination and deubiquitination in the regulation of cancer metabolism, which is aimed at highlighting the importance of this post-translational modification in metabolic reprogramming and supporting the development of new therapeutic approaches for cancer treatment.

Human recombinant FSH induces chemoresistance in human breast cancer cells via HIF-1α activation†

Breast cancer patients under 40 years of age who are candidate to chemotherapy with alkylating drugs may undergo controlled ovarian stimulation (COS) with recombinant human follicle-stimulating hormone (rhFSH) in order to get fertility preservation by mature oocyte cryostorage. The direct effect(s) of exogenous rhFSH on the chemosensitivity of breast cancer is currently unknown. To clarify this issue, we incubated four different breast cancer cell lines with rhFSH (10 IU/L, 24 h) and then we exposed them to doxorubicin (DOX) or cyclophosphamide (CPA). The effect(s) of rhFSH on human breast cancer cells treated with DOX or CPA was measured in terms of (1) cell viability, (2) cytotoxicity, (3) multidrug resistance (MDR) genes and proteins expression and activities, and (4) hypoxia-inducible factor 1-alpha (HIF-1α) activation. Pretreatment with rhFSH significantly increased the viability of breast cancer cells after treatment with DOX or CPA, and reduced the lactate dehydrogenase leakage and reactive oxygen species production. Moreover, after preincubation with rhFSH, the MDR proteins (Pgp, MPR1, and BCRP) expression and activity resulted upregulated and the HIF-1α pathway activated. In addition, the use of a widely used HIF-1α inhibitor, the 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1), prevented the rhFSH effect on the onset of MDR. Taken together, these observations suggest that a short exposure to rhFSH induces chemoresistance to DOX and CPA in human breast cancer cells via HIF-1α activation.

Omega-3 Polyunsaturated Fatty Acids Counteract Inflammatory and Oxidative Damage of Non-Transformed Porcine Enterocytes

Simple Summary

Farm animals frequently suffer from chronic inflammatory diseases due to certain physiological or pathophysiological conditions such as weaning, the periparturient period and infections. Traditionally, antibiotics were added to animal diets to counteract inflammation and enhance growth. However, this leads to the emergence of antibiotic-resistant bacterial species which causes potential health hazards. Over several decades, omega-3 polyunsaturated fatty acids have been known to exhibit a multitude of beneficial effects in animal health and are regarded as a functional food with therapeutic potential. We accessed the bioactivity of omega-3 polyunsaturated fatty acids as eicosapentaenoic acid and docosahexaenoic acid in pig intestinal epithelium under different stress conditions in an in vitro set-up. Our results demonstrated the proliferative and cytoprotective properties of the two fatty acids, which are fundamental to determining the cellular mechanism for efficient utilization in pig diets.

Abstract

Marine and plant-based omega-3 polyunsaturated fatty acids (ω-3 PUFAs) are widely added to animal diets to promote growth and immunity. We tested the hypothesis that eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and their 1:2 combination could counteract acute or long-term damage of lipopolysaccharides (LPS), dextran sodium sulphate (DSS) and hydrogen peroxide (H₂O₂) in Intestinal Porcine Epithelial Cell line-J2 (IPEC-J2). The results showed that 24 h treatment with EPA or DHA exhibited proliferative effects in IPEC-J2 cells at low to moderate concentrations (6.25–50 μM) (p < 0.05). Further, 24 h pretreatment with individual DHA (3.3 µM), EPA (6.7 µM) or as DHA:EPA (1:2; 10 µM) combination increased the mitochondrial activity or cell membrane integrity post-LPS (24 h), DSS (24 h) and H₂O₂ (1 h) challenge (p < 0.05). Additionally, DHA:EPA (1:2, 10 µM) combination decreased the apoptotic caspase-3/7 activity around twofold after 24 h LPS and DSS challenge (p < 0.05). Our study confirms the proliferative and cytoprotective properties of EPA and DHA in IPEC-J2 cells. Increased intracellular mitochondrial activity and cell membrane integrity by ω-3 PUFAs can play a role in preventing enterocyte apoptosis during acute or chronic inflammatory and oxidative stress.

Transcriptomic Response of Breast Cancer Cells MDA-MB-231 to Docosahexaenoic Acid: Downregulation of Lipid and Cholesterol Metabolism Genes and Upregulation of Genes of the Pro-Apoptotic ER-Stress Pathway

Despite considerable efforts in prevention and therapy, breast cancer remains a major public health concern worldwide. Numerous studies using breast cancer cell lines have shown the antiproliferative and pro-apoptotic effects of docosahexaenoic acid (DHA). Some studies have also demonstrated the inhibitory effect of DHA on the migration and invasion of breast cancer cells, making DHA a potential anti-metastatic agent. Thus, DHA has shown its potential as a chemotherapeutic adjuvant. However, the molecular mechanisms triggering DHA effects remain unclear, and the aim of this study was to provide a transcriptomic basis for further cellular and molecular investigations. Therefore, MDA-MB-231 cells were treated with 100 µM DHA for 12 h or 24 h before RNA-seq analysis. The results show the great impact of DHA-treatment on the transcriptome, especially after 24 h of treatment. The impact of DHA is particularly visible in genes involved in the cholesterol biosynthesis pathway that is strongly downregulated, and the endoplasmic reticulum (ER)-stress response that is, conversely, upregulated. This ER-stress and unfolded protein response could explain the pro-apoptotic effect of DHA. The expression of genes related to migration and invasion (especially SERPINE1, PLAT, and MMP11) is also impacted by DHA. In conclusion, this transcriptomic analysis supports the antiproliferative, pro-apoptotic and anti-invasive effects of DHA, and provides new avenues for understanding its molecular mechanisms.

Insights into P-Glycoprotein Inhibitors: New Inducers of Immunogenic Cell Death

Doxorubicin is a strong inducer of immunogenic cell death (ICD), but it is ineffective in P-glycoprotein (Pgp)-expressing cells. Indeed, Pgp effluxes doxorubicin and impairs the immunesensitizing functions of calreticulin (CRT), an "eat-me" signal mediating ICD. It is unknown if classical Pgp inhibitors, designed to reverse chemoresistance, may restore ICD. We addressed this question by using Pgp-expressing cancer cells, treated with Tariquidar, a clinically approved Pgp inhibitor, and R-3 compound, a N,N-bis(alkanol)amine aryl ester derivative with the same potency of Tariquidar as Pgp inhibitor. In Pgp-expressing/doxorubicin-resistant cells, Tariquidar and R-3 increased doxorubicin accumulation and toxicity, reduced Pgp activity, and increased CRT translocation and ATP and HMGB1 release. Unexpectedly, only R-3 promoted phagocytosis by dendritic cells and activation of antitumor CD8⁺T-lymphocytes. Although Tariquidar did not alter the amount of Pgp present on cell surface, R-3 promoted Pgp internalization and ubiquitination, disrupting its interaction with CRT. Pgp knock-out restores doxorubicin-induced ICD in MDA-MB-231/DX cells that recapitulated the phenotype of R-3-treated cells. Our work demonstrates that plasma membrane-associated Pgp prevents a complete ICD notwithstanding the release of ATP and HMGB1, and the exposure of CRT. Pharmacological compounds reducing Pgp activity and amount may act as promising chemo- and immunesensitizing agents.

ABCA1/ABCB1 Ratio Determines Chemo- and Immune-Sensitivity in Human Osteosarcoma

The ATP Binding Cassette transporter B1 (ABCB1) induces chemoresistance in osteosarcoma, because it effluxes doxorubicin, reducing the intracellular accumulation, toxicity, and immunogenic cell death induced by the drug. The ATP Binding Cassette transporter A1 (ABCA1) effluxes isopentenyl pyrophosphate (IPP), a strong activator of anti-tumor Vγ9Vδ2 T-cells. Recruiting this population may represent an alternative strategy to rescue doxorubicin efficacy in ABCB1-expressing osteosarcoma. In this work, we analyzed how ABCA1 and ABCB1 are regulated in osteosarcoma, and if increasing the ABCA1-dependent activation of Vγ9Vδ2 T-cells could be an effective strategy against ABCB1-expressing osteosarcoma. We used 2D-cultured doxorubicin-sensitive human U-2OS and Saos-2 cells, their doxorubicin-resistant sublines (U-2OS/DX580 and Saos-2/DX580), and 3D cultures of U-2OS and Saos-2 cells. DX580-sublines and 3D cultures had higher levels of ABCB1 and higher resistance to doxorubicin than parental cells. Surprisingly, they had reduced ABCA1 levels, IPP efflux, and Vγ9Vδ2 T-cell-induced killing. In these chemo-immune-resistant cells, the Ras/Akt/mTOR axis inhibits the ABCA1-transcription induced by Liver X Receptor α (LXRα); Ras/ERK1/2/HIF-1α axis up-regulates ABCB1. Targeting the farnesylation of Ras with self-assembling nanoparticles encapsulating zoledronic acid (NZ) simultaneously inhibited both axes. In humanized mice, NZ reduced the growth of chemo-immune-resistant osteosarcomas, increased intratumor necro-apoptosis, and ABCA1/ABCB1 ratio and Vγ9Vδ2 T-cell infiltration. We suggest that the ABCB1^highABCA1^low phenotype is indicative of chemo-immune-resistance. We propose aminobisphosphonates as new chemo-immune-sensitizing tools against drug-resistant osteosarcomas.

Adipocytes promote ovarian cancer chemoresistance

Ovarian cancer (OvCa), while accounting for only 3% of all women’s cancer, is the fifth leading cause of cancer death among women. One of the most significant obstacles to successful OvCa treatment is chemoresistance. The current lack of understanding of the driving mechanisms underlying chemoresistance hinders the development of effective therapeutics against this obstacle. Adipocytes are key components of the OvCa microenvironment and have been shown to be involved in OvCa cell proliferation, however, little is known about their impact on OvCa chemoresistance. In the current study, we found that adipocytes, of both subcutaneous and visceral origin, secrete factors that enhance the resistance of OvCa cells against chemotherapeutic drugs by activating the Akt pathway. Importantly, we have demonstrated that secreted lipids mediate adipocyte-induced chemoresistance. Through a comprehensive lipidomic analysis, we have identified this chemo-protective lipid mediator as arachidonic acid (AA). AA acts on OvCa cells directly, not through its downstream derivatives such as prostaglandins, to activate Akt and inhibit cisplatin-induced apoptosis. Taken together, our study has identified adipocytes and their secreted AA as important mediators of OvCa chemoresistance. Strategies that block the production of AA from adipocytes or block its anti-apoptotic function may potentially inhibit chemoresistance in OvCa patients.

Dietary baker's yeast sensitizes Ehrlich mammary adenocarcinoma to paclitaxel in mice bearing tumor

Baker's yeast, Saccharomyces cerevisiae, has been shown to sensitize a variety of breast cancer cell (BCC) lines to paclitaxel chemotherapy in vitro. The present study evaluated the ability of S. cerevisiae to sensitize BCCs to paclitaxel in animals bearing Ehrlich ascites carcinoma (EAC). Mice bearing EAC were intratumorally injected with dead S. cerevisiae (1x107 cells/ml) in the presence or absence of low- and high-dose paclitaxel [paclitaxel-L, 2 mg/kg body weight (BW) and paclitaxel-H, 10 mg/kg BW, respectively]. At 30 days post tumor inoculation, co-treatment with yeast plus paclitaxel-L showed improvements over paclitaxel-H alone, as measured by tumor weight (-64 vs. -53%), DNA damage (+79 vs. +62%), tumor cell apoptosis (+217 vs. +177%), cell proliferation (-56 vs. -42%) and Ki-67 marker (+95 vs. +40%). Histopathology and ultra-structural examinations showed that yeast plus paclitaxel-L enhanced apoptosis in EAC more than paclitaxel-H alone and caused comparable tumor necrosis. We conclude that baker's yeast may be used with low-dose chemotherapy to achieve the same potency as high-dose chemotherapy in mice bearing EAC. This suggests that baker's yeast may be an anticancer adjuvant and may have clinical implications for the treatment of breast cancer.

Omega-3 polyunsaturated fatty acids as adjuvant therapy of colorectal cancer

The majority of evidence linking anti-colorectal cancer (CRC) activity with omega-3 polyunsaturated fatty acids (O3FAs) has focussed on decreased CRC risk (prevention). More recently, preclinical data and human observational studies have begun to make the case for adjuvant treatment of advanced CRC. Herein, we review latest data regarding the effect of O3FAs on post-diagnosis CRC outcomes, including mechanistic preclinical data, evidence that O3FAs have beneficial effects on efficacy and tolerability of CRC chemotherapy, and human epidemiological data linking dietary O3FA intake with CRC outcomes. We also highlight ongoing randomised controlled trials of O3FAs with CRC endpoints and discuss critical gaps in the evidence base, which include limited understanding of the effects of O3FAs on the tumour microenvironment, the host immune response to CRC, and the intestinal microbiome.

G-Protein-Coupled Receptor 120 Mediates DHA-Induced Apoptosis by Regulating IP3R, ROS and, ER Stress Levels in Cisplatin-Resistant Cancer Cells

The omega-3 fatty acid docosahexaenoic acid (DHA) is known to induce apoptosis and cell cycle arrest via the induction of reactive oxygen species (ROS) production and endoplasmic reticulum (ER) stress in many types of cancers. However, the roles of DHA in drug-resistant cancer cells have not been elucidated. In this study, we investigated the effects of DHA in cisplatin-resistant gastric cancer SNU-601/cis2 cells. DHA was found to induce ROS-dependent apoptosis in these cells. The inositol 1,4,5-triphosphate receptor (IP3R) blocker 2-aminoethyl diphenylboninate (2-APB) reduced DHA-induced ROS production, consequently reducing apoptosis. We also found that G-protein-coupled receptor 120 (GPR120), a receptor of long-chain fatty acids, is expressed in SNU-601/cis2 cells, and the knockdown of GPR120 using specific shRNAs alleviated DHA-mediated ROS production and apoptosis. GPR120 knockdown reduced the expression of ER stress response genes, similar to the case for the pre-treatment of the cells with N-acetyl-L-cysteine (NAC), an ROS scavenger, or 2-APB. Indeed, the knockdown of C/EBP homologous protein (CHOP), a transcription factor that functions under ER stress conditions, markedly reduced DHA-mediated apoptosis, indicating that CHOP plays an essential role in the anti-cancer activity of DHA. These results suggest that GPR120 mediates DHA-induced apoptosis by regulating IP3R, ROS, and ER stress levels in cisplatin-resistant cancer cells, and that GPR120 is an effective chemotherapeutic target for cisplatin resistance.

Fatty acids: Adiposity and breast cancer chemotherapy, a bad synergy?

Globally, breast cancer continues to be a major concern in women's health. Lifestyle related risk factors, specifically excess adipose tissue (adiposity) has reached epidemic proportions and has been identified as a major risk factor in the development of breast cancer. Dysfunctional adipose tissue has evoked research focusing on its association with metabolic-related conditions, breast cancer risk and progression. Adipose dysfunction in coordination with immune cells and inflammation, are responsible for accelerated cell growth and survival of cancer cells. Recently, evidence also implicates adiposity as a potential risk factor for chemotherapy resistance. Chemotherapeutic agents have been shown to negatively impact adipose tissue. Since adipose tissue is a major storage site for fatty acids, it is not unlikely that these negative effects may disrupt adipose tissue homeostasis. It is therefore argued that fatty acid composition may be altered due to the chemotherapeutic pharmacokinetics, which in turn could have severe health related outcomes. The underlying molecular mechanisms elucidating the effects of fatty acid composition in adiposity-linked drug resistance are still unclear and under explored. This review focuses on the potential role of adiposity in breast cancer and specifically emphasizes the role of fatty acids in cancer progression and treatment resistance.

Pyruvate Treatment Restores the Effectiveness of Chemotherapeutic Agents in Human Colon Adenocarcinoma and Pleural Mesothelioma Cells

Emerging evidence supports the idea that a dysfunction in cell metabolism could sustain a resistant phenotype in cancer cells. As the success of chemotherapeutic agents is often questioned by the occurrence of multidrug resistance (MDR), a multiple cross-resistance towards different anti-cancer drugs represent a major obstacle to cancer treatment. The present study has clarified the involvement of the carbon metabolites in a more aggressive tumor colon adenocarcinoma phenotype and in a chemoresistant mesothelioma, and the role of pyruvate treatment in the reversion of the potentially related resistance. For the first time, we have shown that human colon adenocarcinoma cells (HT29) and its chemoresistant counterpart (HT29-dx) displayed different carbon metabolism: HT29-dx cells had a higher glucose consumption compared to HT29 cells, whereas human malignant mesothelioma (HMM) cells showed a lower glucose consumption compared to HT29 cells, accompanied by a lower pyruvate production and, consequently, a higher production of lactate. When treated with pyruvate, both HT29-dx and HMM cells exhibited a re-established accumulation of doxorubicin and a lower survival ability, a decreased activity of multidrug resistance protein 1 (MRP1) and a restored mitochondrial respiratory chain function, improving the effectiveness of the chemotherapeutic agents in these resistant cancer cells.

Hyperglycemia Promotes Chemoresistance Through the Reduction of the Mitochondrial DNA Damage, the Bax/Bcl-2 and Bax/Bcl-XL Ratio, and the Cells in Sub-G1 Phase Due to Antitumoral Drugs Induced-Cytotoxicity in Human Colon Adenocarcinoma Cells

Diabetes and cancer are common, chronic, and potentially fatal diseases that frequently co-exist. Observational studies clearly indicate that the risk of several types of cancer is increased in diabetic patients and a number of cancer types have shown a higher mortality rate in patients with hyperglycemic associated pathologies. This scenario could be due, at least in part, to a lower efficacy of the cancer treatments which needs to be better investigated. Here, we evaluated the effects of a prolonged exposure to high glucose (HG) to the response to chemotherapy on human colon adenocarcinoma HT29 and LOVO cell lines. We observed that hyperglycemia protected against the decreased cell viability and cytotoxicity and preserved from the mitochondrial DNA lesions induced by doxorubicin (DOX) and 5-fluorouracil (5-FU) treatments by lowering ROS production. In HT29 cells the amount of intracellular DOX and its nuclear localization were not modified by HG incubation in terms of Pgp, BCRP, MRP1, 5 and 8 activity and gene expression. On the contrary, in LOVO cells, the amount of intracellular DOX was significantly decreased after a bolus of DOX in HG condition and the expression and activity of MPR1 was increased, suggesting that HG promotes drug chemoresistance in both HT29 and LOVO cells, but in a different way. In both cell types, HG condition prevented the susceptibility to apoptosis by decreasing the ratio Bax/Bcl-2 and Bax/Bcl-XL and diminished the level of cytosolic cytochrome c and the cleavage of full length of PARP induced by DOX and 5-FU. Finally, hyperglycemia reduced cell death by decreasing the cell percentage in sub-G1 peak induced by DOX (via a cell cycle arrest in the G2/M phase) and 5-FU (via a cell cycle arrest in the S phase) in HT29 and LOVO cells. Taken together, our data showed that a prolonged exposure to HG protects human colon adenocarcinoma cells from the cytotoxic effects of two widely used chemotherapeutic drugs, impairing the effectiveness of the chemotherapy itself.

Transcriptional signatures for coupled predictions of stage II and III colorectal cancer metastasis and fluorouracil-based adjuvant chemotherapy benefit

The current study suggests that the identification of predictive signatures of fluorouracil (5-FU) response for stage II and III colorectal cancer (CRC) could be confounded by chemotherapy-irrelevant low relapse risk. Using the samples of patients with stage II and III CRC who were treated with curative surgery only, we identified a signature with which to predict chemotherapy-irrelevant relapse risk for patients after curative surgery. By applying this signature to the samples of patients with stage II and III CRC who were treated with 5-FU-based adjuvant chemotherapy (ACT) after surgery, we predicted the relapse risk if treated with surgery only. From high-risk samples, we further identified another signature with which to predict therapeutic benefit from 5-FU-based ACT. On the basis of the relative expression orderings of gene pairs, a postsurgery relapse risk signature that consisted of 44 gene pairs was developed and verified in 3 independent data sets. A 5-FU therapeutic benefit signature that consisted of 4 gene pairs was then developed to predict the response of 5-FU-based ACT for those patients with high relapse risk after curative surgery. The signature was verified in 4 independent datasets. For patients with stage II and III CRC, the coupled signatures can first identify patients with high relapse risk after curative surgery, then predict therapeutic benefit from 5-FU-based ACT.-Song, K., Guo, Y., Wang, X., Cai, H., Zheng, W., Li, N., Song, X., Ao, L., Guo, Z., Zhao, W. Transcriptional signatures for coupled predictions of stage II and III colorectal cancer metastasis and fluorouracil-based adjuvant chemotherapy benefit.

Brain endocannabinoid signaling exhibits remarkable complexity

The endocannabinoid (eCB) signaling system is one of the most extensive of the mammalian brain. Despite the involvement of only few specific ligands and receptors, the system encompasses a vast diversity of triggered mechanisms and driven effects. It mediates a wide range of phenomena, including the regulation of transmitter release, neural excitability, synaptic plasticity, impulse spread, long-term neuronal potentiation, neurogenesis, cell death, lineage segregation, cell migration, inflammation, oxidative stress, nociception and the sleep cycle. It is also known to be involved in the processes of learning and memory formation. This extensive scope of action is attained by combining numerous variables. In a properly functioning brain, the correlations of these variables are kept in a strictly controlled balance; however, this balance is disrupted in many pathological conditions. However, while this balance is known to be disrupted by drugs in the case of addicts, the stimuli and mechanisms influencing the neurodegenerating brain remain elusive. This review examines the multiple factors and phenomena affecting the eCB signaling system in the brain. It evaluates techniques of controlling the eCB system to identify the obstacles in their applications and highlights the crucial interdependent variables that may influence biomedical research outcomes.

Pro-inflammatory and anti-inflammatory compounds exert similar effects on P-glycoprotein in blood–brain barrier endothelial cells

Objectives

The effects of anti-inflammatory glucocorticoids dexamethasone (DX) and hydrocortisone (HC), pro-inflammatory cytokine interleukin-1β (IL-1β) and dietary long-chain polyunsaturated fatty acids (PUFAs) on expression and activity of the ATP-binding cassette transporter P-glycoprotein (P-GP) were studied in porcine brain endothelial cells (PBECs).

Methods

Primary PBECs were treated for 24 h with glucocorticoids, IL-1β and long-chain PUFAs. P-GP activity was determined by measuring intracellular calcein accumulation and P-GP expression by Western blotting. The effect of PUFAs on membrane fluidity was assessed by fluorescence recovery after photobleaching (FRAP).

Key findings

Dexamethasone, HC and IL-1β significantly increased P-GP expression and activity. The effect of IL-1β was attenuated by the IL-1 receptor antagonist (IL-1RA). This is the first report of the combined actions of IL-1β and IL-1RA on P-GP expression and the first evidence of glucocorticoid-mediated P-GP up-regulation in PBECs. Arachidonic acid (AA), docosahexaenoic acid (DHA) and eicosapentenoic acid (EPA) significantly decreased P-GP activity without affecting expression or membrane fluidity. AA, DHA and EPA counteracted IL-1β-mediated increases in P-GP activity, while AA and EPA, but not DHA, counteracted glucocorticoid-mediated increase in P-GP activity.

Conclusions

While glucocorticoids and IL-1β possess opposing actions in inflammation, they demonstrate functional consistency by increasing P-GP expression and activity in PBECs.

Zoledronic acid-encapsulating self-assembling nanoparticles and doxorubicin: a combinatorial approach to overcome simultaneously chemoresistance and immunoresistance in breast tumors

The resistance to chemotherapy and the tumor escape from host immunosurveillance are the main causes of the failure of anthracycline-based regimens in breast cancer, where an effective chemo-immunosensitizing strategy is lacking.

The clinically used aminobisphosphonate zoledronic acid (ZA) reverses chemoresistance and immunoresistance in vitro. Previously we developed a nanoparticle-based zoledronic acid-containing formulation (NZ) that allowed a higher intratumor delivery of the drug compared with free ZA in vivo. We tested its efficacy in combination with doxorubicin in breast tumors refractory to chemotherapy and immune system recognition as a new combinatorial approach to produce chemo- and immunosensitization.

NZ reduced the IC₅₀ of doxorubicin in human and murine chemoresistant breast cancer cells and restored the doxorubicin efficacy against chemo-immunoresistant tumors implanted in immunocompetent mice. By reducing the metabolic flux through the mevalonate pathway, NZ lowered the activity of Ras/ERK1/2/HIF-1α axis and the expression of P-glycoprotein, decreased the glycolysis and the mitochondrial respiratory chain, induced a cytochrome c/caspase 9/caspase 3-dependent apoptosis, thus restoring the direct cytotoxic effects of doxorubicin on tumor cell. Moreover, NZ restored the doxorubicin-induced immunogenic cell death and reversed the tumor-induced immunosuppression due to the production of kynurenine, by inhibiting the STAT3/indoleamine 2,3 dioxygenase axis. These events increased the number of dendritic cells and decreased the number of immunosuppressive T-regulatory cells infiltrating the tumors.

Our work proposes the use of nanoparticle encapsulating zoledronic acid as an effective tool overcoming at the same time chemoresistance and immunoresistance in breast tumors, thanks to the effects exerted on tumor cell and tumor-infiltrating immune cells.

ω-3 Long Chain Polyunsaturated Fatty Acids as Sensitizing Agents and Multidrug Resistance Revertants in Cancer Therapy

Chemotherapy efficacy is strictly limited by the resistance of cancer cells. The ω-3 long chain polyunsaturated fatty acids (ω-3 LCPUFAs) are considered chemosensitizing agents and revertants of multidrug resistance by pleiotropic, but not still well elucidated, mechanisms. Nowadays, it is accepted that alteration in gene expression, modulation of cellular proliferation and differentiation, induction of apoptosis, generation of reactive oxygen species, and lipid peroxidation are involved in ω-3 LCPUFA chemosensitizing effects. A crucial mechanism in the control of cell drug uptake and efflux is related to ω-3 LCPUFA influence on membrane lipid composition. The incorporation of docosahexaenoic acid in the lipid rafts produces significant changes in their physical-chemical properties affecting content and functions of transmembrane proteins, such as growth factors, receptors and ATP-binding cassette transporters. Of note, ω-3 LCPUFAs often alter the lipid compositions more in chemoresistant cells than in chemosensitive cells, suggesting a potential adjuvant role in the treatment of drug resistant cancers.

Protective Effects of ω-3 PUFA in Anthracycline-Induced Cardiotoxicity: A Critical Review

It has been demonstrated that ω-3 polyunsaturated fatty acids (ω-3 PUFA) may exert a beneficial role as adjuvants in the prevention and treatment of many disorders, including cardiovascular diseases and cancer. Particularly, several in vitro and in vivo preclinical studies have shown the antitumor activity of ω-3 PUFA in different kinds of cancers, and several human studies have shown that ω-3 PUFA are able to decrease the risk of a series of cardiovascular diseases. Several mechanisms have been proposed to explain their pleiotropic beneficial effects. ω-3 PUFA have also been shown to prevent harmful side-effects (including cardiotoxicity and heart failure) induced by conventional and innovative anti-cancer drugs in both animals and patients. The available literature regarding the possible protective effects of ω-3 PUFA against anthracycline-induced cardiotoxicity, as well as the mechanisms involved, will be critically discussed herein. The study will analyze the critical role of different levels of ω-3 PUFA intake in determining the results of the combinatory studies with anthracyclines. Suggestions for future research will also be considered.

Baker's Yeast Sensitizes Metastatic Breast Cancer Cells to Paclitaxel In Vitro

Our earlier studies have demonstrated that phagocytosis of baker's yeast ( Saccharomyces cerevisiae) induces apoptosis in different cancer cell lines in vitro and in vivo. This study aimed to examine how baker's yeast sensitizes murine and human breast cancer cells (BCC) to paclitaxel in vitro. This sensitizing effect makes lower concentrations of chemotherapy more effective at killing cancer cells, thereby enhancing the capacity of treatment. Three BCC lines were used: the metastatic murine 4T1 line, the murine Ehrlich ascites carcinoma (EAC) line, and the human breast cancer MCF-7 line. Cells were cultured with different concentrations of paclitaxel in the presence or absence of baker's yeast. Cell survival and the IC₅₀ values were determined by MTT assay and trypan blue exclusion method. Percent of DNA damage, apoptosis, and cell proliferation were examined by flow cytometry. Yeast alone and paclitaxel alone significantly decreased 4T1 cell viability postculture (24 and 48 hours), caused DNA damage, increased apoptosis, and suppressed cell proliferation. Baker's yeast in the presence of paclitaxel increased the sensitivity of 4T1 cells to chemotherapy and caused effects that were greater than either treatment alone. The chemosensitizing effect of yeast was also observed with murine EAC cells and human MCF-7 cells, but to a lesser extent. These data suggest that dietary baker's yeast is an effective chemosensitizer and can enhance the apoptotic capacity of paclitaxel against breast cancer cells in vitro. Baker's yeast may represent a novel adjuvant for chemotherapy treatment.