[Congenital abnormalities of the atrioventricular ostia and the annexed valves: report of a case of an extra hole in the posterolateral cuspis of the mitral valve]

Cell death and DNA damage via ROS mechanisms after applied antibiotics and antioxidants doses in prostate hyperplasia primary cell cultures

Tumor heterogeneity results in aggressive cancer phenotypes with acquired resistance. However, combining chemical treatment with adjuvant therapies that cause cellular structure and function perturbations may diminish the ability of cancer cells to resist at chemical treatment and lead to a less aggressive cancer phenotype. Applied treatments on prostate hyperplasia primary cell cultures exerted their antitumor activities through mechanisms including cell cycle blockage, oxidative stress, and cell death induction by flow cytometry methods. A 5.37 mM Chloramphenicol dose acts on prostate hyperplasia cells by increasing the pro-oxidant status, inducing apoptosis, autophagy, and DNA damage, but without ROS changes. Adding 6.30 mM vitamin C or 622 µM vitamin E as a supplement to 859.33 µM Chloramphenicol dose in prostate hyperplasia cells determines a significant increase of ROS level for a part of cells. However, other cells remain refractory to initial ROS, with significant changes in apoptosis, autophagy, and cell cycle arrest in G0/G1 or G2/M. When the dose of Chloramphenicol was increased to 5.37 mM for 6.30 mM of vitamin C, prostate hyperplasia cells reacted by ROS level drastically decreased, cell cycle arrest in G2/M, active apoptosis, and autophagy. The pro-oxidant action of 1.51 mM Erythromycin dose in prostate hyperplasia cell cultures induces changes in the apoptosis mechanisms and cell cycle arrest in G0/G1. Addition of 6.30 mM vitamin C to 1.51 mM Erythromycin dose in hyperplasia cell cultures, the pro-oxidant status determines diminished caspase 3/7 mechanism activation, but ROS level presents similar changes as Chloramphenicol dose and cell cycle arrest in G2/M. Flow cytometric analysis of cell death, oxidative stress, and cell cycle are recommended as laboratory techniques in therapeutic and diagnostic fields.

High-dose vitamin C as a metabolic treatment of cancer: a new dimension in the era of adjuvant and intensive therapy

The anti-cancer mechanism of High-dose Vitamin C (HDVC) is mainly to participate in the Fenton reaction, hydroxylation reaction, and epigenetic modification, which leads to the energy crisis, metabolic collapse, and severe peroxidation stress that results in the proliferation inhibition or death of cancer cells. However, the mainstream view is that HDVC does not significantly improve cancer treatment outcomes. In clinical work and scientific research, we found that some drugs or therapies can significantly improve the anti-cancer effects of HDVC, such as PD-1 inhibitors that can increase the anti-cancer effects of cancerous HDVC by nearly three times. Here, the adjuvant and intensive therapy and synergistic mechanisms including HDVC combined application of chemoradiotherapies multi-vitamins, targeted drugs, immunotherapies, and oncolytic virus are discussed in detail. Adjuvant and intensive therapy of HDVC can significantly improve the therapeutic effect of HDVC in the metabolic treatment of cancer, but more clinical evidence is needed to support its clinical application.

A yeast-malic acid crosslinker/polyacrylic acid hydrogel containing doxycycline for the treatment of periodontitis

Doxycycline (DX) is a drug of choice for the treatment of periodontitis, with the limitation of requiring a high dose, which may be overcome by the preparation of a targeted controlled-release hydrogel containing a newly synthesized yeast-malic acid crosslinker (YMC). YMC was synthesized via thermochemical modification of yeast with malic acid at 100-140 °C and compared with glutaraldehyde-saturated toluene (GST). Swelling capacity, acid and carboxyl content, scanning electron microscopy (SEM) imaging, Brunauer-Emmett-Teller (BET) analysis, viscosity, cross-linking density, DX loading and release behavior at pH 6.5, mucoadhesion, and antimicrobial and periodontal efficacy of the glutaraldehyde hydrogel (HGG) and YMC hydrogel (HGY) were compared. Changes from C-O (1421 cm-1) to C[double bond, length as m-dash]OOR (1702 cm-1) in the infrared spectroscopy, along with changes in the degree of substitution from 0 to 0.39, degree of esterification from 0 to 40 ± 1.5 and COOH content from 129 ± 0.5 to 290 ± 0.5 (meq. per 100 g), were found between yeast to YMC, respectively. The results revealed 1.5 times more dynamic swelling, 0.25-fold decrease in acid content, 2.3-fold increase in carboxyl content, and 1.2- and 2.1-fold increases in cross-linking density and viscosity of HGY as compared to HGG, respectively. The SEM and BET results revealed that HGY had a 2 times greater porous surface than HGG. HGY/DX was 35 ± 2% more effective in controlling periodontitis bacteria, decreased periodontal depth from 4 to 3.2 mm, and gingival index from 3 to 1 as compared to HGG/DX in patients suffering from periodontitis. HGY/DX not only serves as a tool for the controlled release of DX in periodontal pockets but also contributes to the treatment of gingival periodontitis.

Role of Autophagy and AMPK in Cancer Stem Cells: Therapeutic Opportunities and Obstacles in Cancer

Cancer stem cells represent a resilient subset within the tumor microenvironment capable of differentiation, regeneration, and resistance to chemotherapeutic agents, often using dormancy as a shield. Their unique properties, including drug resistance and metastatic potential, pose challenges for effective targeting. These cells exploit certain metabolic processes for their maintenance and survival. One of these processes is autophagy, which generally helps in energy homeostasis but when hijacked by CSCs can help maintain their stemness. Thus, it is often referred as an Achilles heel in CSCs, as certain cancers tend to depend on autophagy for survival. Autophagy, while crucial for maintaining stemness in cancer stem cells (CSCs), can also serve as a vulnerability in certain contexts, making it a complex target for therapy. Regulators of autophagy like AMPK (5' adenosine monophosphate-activated protein kinase) also play a crucial role in maintaining CSCs stemness by helping CSCs in metabolic reprogramming in harsh environments. The purpose of this review is to elucidate the interplay between autophagy and AMPK in CSCs, highlighting the challenges in targeting autophagy and discussing therapeutic strategies to overcome these limitations. This review focuses on previous research on autophagy and its regulators in cancer biology, particularly in CSCs, addresses the remaining unanswered questions, and potential targets for therapy are also brought to attention.

A doxycycline-loaded microfiber of poly-metformin/PCL for eradicating melanoma stem cells

Nowadays, electrospun fibrous mats are used as drug delivery systems for loading of potential drugs in order to kill cancer cells. In the study, a skin patch for treating melanoma cancer after surgery was made using polycaprolactone and polymetformin microfibers that were loaded with doxycycline (PolyMet/PCL@DOX), an anti-cancer stem cell agent. The morphology, structure, mechanical characteristics, swelling, and porosity of the electrospun microfibers were examined. Drug release andanticancereffectiveness of PolyMet/PCL@DOXwas evaluated against A375 melanoma cancer stem cells using the MTS, Flow cytometry, colony formation and CD44 expression assays. Scanning electron microscopy (SEM) verified the micro fibrous structure with a diameter of about 2.31 µm. The porosity and swelling percentages for microfibers was 73.5 % and 2.9 %, respectively. The tensile strength at the breaking point was equal to 3.84 MPa. The IC50 of PolyMet/PCL@DOX was 7.4 μg/mL. The survival rate of A375 cells after 72 h of PolyMet/PCL@DOX treatment was 43.9 %. The colony formation capacity of A375 cells decreased after PolyMet/PCL@DOX treatment. The level of CD44 expression in the PolyMet/PCL@DOX group decreased compared to the control group. Generally, PolyMet/PCL@DOX microfibers can be a promising candidate as a patch after surgery to eradicate cancer stem cells, effectively.

Transcriptome-Wide Association Study Reveals New Molecular Interactions Associated with Melanoma Pathogenesis

A transcriptome-wide association study (TWAS) was conducted on genome-wide association study (GWAS) summary statistics of malignant melanoma of skin (UK Biobank dataset) and The Cancer Genome Atlas-Skin Cutaneous Melanoma (TCGA-SKCM) gene expression weights to identify melanoma susceptibility genes. The GWAS included 2465 cases and 449,799 controls, while the gene expression testing was conducted on 103 cases. Afterward, a gene enrichment analysis was applied to identify significant TWAS associations. The melanoma's gene-microRNA (miRNA) regulatory network was constructed from the TWAS genes and their corresponding miRNAs. At last, a disease enrichment analysis was conducted on the corresponding miRNAs. The TWAS detected 27 genes associated with melanoma with p-values less than 0.05 (the top three genes are LOC389458 (RBAK), C16orf73 (MEIOB), and EIF3CL). After the joint/conditional test, one gene (AMIGO1) was dropped, resulting in 26 significant genes. The Gene Ontology (GO) biological process associated the extended gene set (76 genes) with protein K11-linked ubiquitination and regulation of cell cycle phase transition. K11-linked ubiquitin chains regulate cell division. Interestingly, the extended gene set was related to different skin cancer subtypes. Moreover, the enriched pathways were nsp1 from SARS-CoV-2 that inhibit translation initiation in the host cell, cell cycle, translation factors, and DNA repair pathways full network. The gene-miRNA regulatory network identified 10 hotspot genes with the top three: TP53, BRCA1, and MDM2; and four hotspot miRNAs: mir-16, mir-15a, mir-125b, and mir-146a. Melanoma was among the top ten diseases associated with the corresponding (106) miRNAs. Our results shed light on melanoma pathogenesis and biologically significant molecular interactions.

Vitamin C, doxycycline, and azithromycin (VDA) targeted changes in cellular senescence-related genes in human adipose-derived mesenchymal stem cells

Objectives

Adipose-derived Mesenchymal stem cells (ASCs) have garnered attention for their regenerative potential; therefore, their cellular senescence-related gene expression remains crucial in therapeutic contexts. Nowadays, combination therapies have shown promising results in reducing senescent cells. This study investigated the effects of vitamin C, doxycycline, and azithromycin co-treatment on the key cellular senescence-associated genes in ASCs.

Materials and Methods

Human ASCs were cultured and treated for 24 hr with vitamin C, doxycycline, azithromycin, and a combination of three drugs. Total RNAs were extracted, and the expression of p21, p16, Nanog, Oct4, and Sox2 genes was assessed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Additionally, cell cycle alterations were analyzed via flow cytometry after treatment with these compounds.

Results

Notably, vitamin C treatment resulted in a significant down-regulation of p21 gene expression (P<0.01), implicating the potential role of vitamin C in promoting cell cycle progression. Doxycycline treatment led to a significant up-regulation of p21 and p16 gene expression (P<0.05), as it has previously been shown to induce cell cycle arrest. Similarly, azithromycin treatment predominantly increased p21 expression (P<0.05). Besides, cell cycle analysis revealed that each compound had changed the distribution of cells across different phases of the cell cycle.

Conclusion

The combined use of all three drugs yielded intricate interactions, suggesting a complex yet promising approach to future research. According to our findings, the major difference in the combination drug-treated group (VDA) can be explained by the neutralizing effect of these three components in the environment.

Integrated analysis of single-cell RNA-seq and bulk RNA-seq to unravel the molecular mechanisms underlying the immune microenvironment in the development of intestinal-type gastric cancer

Intestinal-type gastric cancer (IGC) is the most frequent type of gastric cancer in high-incidence populations. The early stages of IGC growth successively include nonatrophic gastritis (NAG), chronic atrophic gastritis (CAG) and intestinal metaplasia (IM). However, the mechanisms of IGC development through these stages remain unclear. For this study, single-cell RNA-seq data related to IGC were downloaded from the GEO database, and immune cells of the tumor microenvironment (TME) were annotated using R software. Changes in the proportion of immune cells and altered cell-to-cell interactions were explored at different disease stages using R software, with a focus on plasma cells. Additionally, IGC samples from the TCGA database were used for immune cell infiltration analysis, and a Cox proportional risk regression model was constructed to identify possible prognostic genes. The results indicated that for precancerous lesions, interactions between immune cells were mainly dominated by chemokines to stimulate the infiltration and activation of immune cells. In tumors, intercellular movement of upregulated molecules and amplified signals were associated with the tumor necrosis factor family and immunosuppression to escape immune surveillance and promote tumor growth. Regarding prognostic analysis, IGLC3, IGLV1-44, IGKV1-16, IGHV3-21, IGLV1-51, and IGLV3-19 were found to be novel biomarkers for IGC. Our analysis of the IGC single-cell atlas together with bulk transcriptome data contributes to understanding TME heterogeneity at the molecular level during IGC development and provides insights for elucidating the mechanism of IGC and discovering novel targets for precise therapy.

Drug repurposing: A novel strategy to target cancer stem cells and therapeutic resistance

Chemotherapy is an effortless and frequently used approach in cancer therapy. However, in most cases, it can only prolong life expectancy and does not guarantee a complete cure. Furthermore, chemotherapy is associated with severe adverse effects, one of the major complications of effective cancer therapy. In addition, newly published research outputs show that cancer stem cells are involved in cancer disease progression, drug resistance, metastasis, and recurrence and that they are functional in the trans-differentiation capacity of cancer stem cells to cancer cells in response to treatments. Novel strategies are therefore required for better management of cancer therapy. The prime approach would be to synthesize and develop novel drugs that need extensive resources, time, and endurance to be brought into therapeutic use. The subsequent approach would be to screen the anti-cancer activity of available non-cancerous drugs. This concept of repurposing non-cancer drugs as an alternative to current cancer therapy has become popular in recent years because using existing anticancer drugs has several adverse effects. Micronutrients have also been investigated for cancer therapy due to their significant anti-cancer effects with negligible or no side effects and availability in food sources. In this paper, we discuss an ideal hypothesis for screening available non-cancerous drugs with anticancer activity, with a focus on cancer stem cells and their clinical application for cancer treatment. Further, drug repurposing and the combination of micronutrients that can target both cancers and cancer stem cells may result in a better therapeutic approach leading to maximum tumor growth control.

Metabolic Profiles of Cancer Stem Cells and Normal Stem Cells and Their Therapeutic Significance

Cancer stem cells (CSCs) are a rare cancer cell population, responsible for the facilitation, progression, and resistance of tumors to therapeutic interventions. This subset of cancer cells with stemness and tumorigenic properties is organized in niches within the tumor microenvironment (TME) and presents altered regulation in a variety of metabolic pathways, including glycolysis, oxidative phosphorylation (OXPHOS), as well as lipid, amino acid, and iron metabolism. CSCs exhibit similarities as well as differences when comparedto normal stem cells, but also possess the ability of metabolic plasticity. In this review, we summarize the metabolic characteristics of normal, non-cancerous stem cells and CSCs. We also highlight the significance and implications of interventions targeting CSC metabolism to potentially achieve more robust clinical responses in the future.

Modulatory Effect of Vitamin C on Hypoxia Induced Breast Cancer Stem Cells

Purpose

Eliminating cancer stem cells (CSCs) is a challenge because of their enhanced resistance to anti-cancer drugs. Vitamin C, which is insufficient in patients with higher stages of cancer, has been gaining attention as a potential treatment for human malignancies. Hence this study aimed to analyze the effect of high-dose vitamin C treatment on the gene expression level of HIF-1α, NF-κB1, BAX, and DNMT1 in the MCF7 cells undergoing hypoxia, as an inducer of CSCs characteristics. As a result, vitamin C could be possibly used as a promising therapeutic adjuvant.

Methods

Here we first analyzed the breast CSC population alteration in MCF7 cells following hypoxia induction. Then, we evaluated the impact of vitamin C treatment on the gene expression level of four stemness-related genes in hypoxic MCF7 cells.

Results

Our results indicate that vitamin C could reduce proliferation and stemness states in CSCs possibly by induction of apoptotic markers such as BAX, along with attenuating stemness markers, including NF-κB1, and DNMT1 gene expressions.

Conclusion

According to our findings, vitamin C administration would become a new approach to avoiding the stimulation of CSCs during cancer therapies.

The Mitochondrial ATP Synthase/IF1 Axis in Cancer Progression: Targets for Therapeutic Intervention

Cancer poses a significant global health problem with profound personal and economic implications on National Health Care Systems. The reprograming of metabolism is a major trait of the cancer phenotype with a clear potential for developing effective therapeutic strategies to combat the disease. Herein, we summarize the relevant role that the mitochondrial ATP synthase and its physiological inhibitor, ATPase Inhibitory Factor 1 (IF1), play in metabolic reprogramming to an enhanced glycolytic phenotype. We stress that the interplay in the ATP synthase/IF1 axis has additional functional roles in signaling mitohormetic programs, pro-oncogenic or anti-metastatic phenotypes depending on the cell type. Moreover, the same axis also participates in cell death resistance of cancer cells by restrained mitochondrial permeability transition pore opening. We emphasize the relevance of the different post-transcriptional mechanisms that regulate the specific expression and activity of ATP synthase/IF1, to stimulate further investigations in the field because of their potential as future targets to treat cancer. In addition, we review recent findings stressing that mitochondria metabolism is the primary altered target in lung adenocarcinomas and that the ATP synthase/IF1 axis of OXPHOS is included in the most significant signature of metastatic disease. Finally, we stress that targeting mitochondrial OXPHOS in pre-clinical mouse models affords a most effective therapeutic strategy in cancer treatment.

RAGE inhibition blunts insulin-induced oncogenic signals in breast cancer

The receptor for advanced glycation end products (RAGE) is implicated in diabetes and obesity complications, as well as in breast cancer (BC). Herein, we evaluated whether RAGE contributes to the oncogenic actions of Insulin, which plays a key role in BC progression particularly in obese and diabetic patients. Analysis of the publicly available METABRIC study, which collects gene expression and clinical data from a large cohort (n = 1904) of BC patients, revealed that RAGE and the Insulin Receptor (IR) are co-expressed and associated with negative prognostic parameters. In MCF-7, ZR75 and 4T1 BC cells, as well as in patient-derived Cancer-Associated Fibroblasts, the pharmacological inhibition of RAGE as well as its genetic depletion interfered with Insulin-induced activation of the oncogenic pathway IR/IRS1/AKT/CD1. Mechanistically, IR and RAGE directly interacted upon Insulin stimulation, as shown by in situ proximity ligation assays and coimmunoprecipitation studies. Of note, RAGE inhibition halted the activation of both IR and insulin like growth factor 1 receptor (IGF-1R), as demonstrated in MCF-7 cells KO for the IR and the IGF-1R gene via CRISPR-cas9 technology. An unbiased label-free proteomic analysis uncovered proteins and predicted pathways affected by RAGE inhibition in Insulin-stimulated BC cells. Biologically, RAGE inhibition reduced cell proliferation, migration, and patient-derived mammosphere formation triggered by Insulin. In vivo, the pharmacological inhibition of RAGE halted Insulin-induced tumor growth, without affecting blood glucose homeostasis. Together, our findings suggest that targeting RAGE may represent an appealing opportunity to blunt Insulin-induced oncogenic signaling in BC.

A metabolism targeting three-pronged attack significantly attenuates breast cancer stem cell related markers toward therapeutic application

Tumor metabolism has provided researchers with a promising window to cancer therapy. The metabolic pathways adopted by cancer cells are different from those of normal cells. Thus, metabolism can be considered a linchpin in targeted cancer therapy. Glycolysis, pentose phosphate pathway, and mitochondria represent three critical metabolic spots with important roles in cancer cell survival and proliferation. In the present study, we aimed to target these pathways using three different inhibitors: 2-deoxyglucose, 6-aminonicotinamide, and doxycycline, separately and in combination. Accordingly, cell viability, lactate production, cell cycle profile, apoptotic profile, and expression of surface and molecular markers of MCF-7 and MDA-MB-231 breast cancer cell lines were investigated under adherent and sphere conditions. Our results from our set conditions indicated various inhibitory effects of these compounds on the breast cancer cell lines. Based on this all-around attack, the combination of drugs demonstrated the most effective inhibitory action compared to separate usage. This study suggests the combined application of these drugs in future investigations and more experimental settings in order to introduce this therapeutic strategy as an efficient anti-cancer treatment.

Doxorubicin induces cardiomyocyte death owing to the accumulation of dysfunctional mitochondria by inhibiting the autophagy fusion process

Doxorubicin (Dox), an anthracycline antibiotic, is an anticancer drug that inhibits DNA replication and cellular metabolic processes in cancer cells with high proliferative potential. However, Dox causes severe side effects, including myocardial damage and heart failure, but the molecular mechanism underlying Dox-induced myocardial injury remains uncertain. In the present study, we evaluated the effects of Dox on the mitochondrial quality control system and regulation of mitochondrial respiration and autophagy in an in vitro rat myoblast H9c2 cell culture model using western blotting, immunohistochemistry, the Seahorse XF24 system, and flow cytometry. Our results showed that Dox did not impair the initiation of autophagic flux or the functions of lysosomes; however, Dox affected the mitochondrial quality control system, leading to a fission-dominant morphology and impaired regulation of mitochondrial respiration, thereby increasing oxidative stress and inhibited progression of autophagy, particularly the fusion of autophagosomes with lysosomes. This inhibition caused a significant decrease in the formation of autolysosomes and was responsible for the accumulation of dysfunctional mitochondria and subsequent increase in oxidative stress, eventually leading to increased myocardial cell death.

Identification of natural products and FDA-approved drugs for targeting cancer stem cell (CSC) propagation

Here, we report the identification of key compounds that effectively inhibit the anchorage-independent growth and propagation of cancer stem cells (CSCs), as determined via screening using MCF7 cells, a human breast adenocarcinoma cell line. More specifically, we employed the mammosphere assay as an experimental format, which involves the generation of 3D spheroid cultures, using low-attachment plates. These positive hit compounds can be divided into 5 categories: 1) dietary supplements (quercetin and glucosamine); 2) FDA-approved drugs (carvedilol and ciprofloxacin); 3) natural products (aloe emodin, aloin, tannic acid, chlorophyllin copper salt, azelaic acid and adipic acid); 4) flavours (citral and limonene); and 5) vitamins (nicotinamide and nicotinic acid). In addition, for the compounds quercetin, glucosamine and carvedilol, we further assessed their metabolic action, using the Seahorse to conduct metabolic flux analysis. Our results indicate that these treatments can affect glycolytic flux and suppress oxidative mitochondrial metabolism (OXPHOS). Therefore, quercetin, glucosamine and carvedilol can reprogram the metabolic phenotype of breast cancer cells. Despite having diverse chemical structures, these compounds all interfere with mitochondrial metabolism. As these compounds halt CSCs propagation, ultimately, they may have therapeutic potential.

Assessment of the In Vitro Cytotoxic Profile of Two Broad-Spectrum Antibiotics-Tetracycline and Ampicillin-On Pharyngeal Carcinoma Cells

Background and Objectives: In spite of the fact that antibiotics are considered to be the cornerstone of modern medicine, their use in the treatment of cancer remains controversial. In the present study, the main objective was to examine the effects of two antibiotics—tetracycline and ampicillin—on the viability, morphology, migration, and organization and structure of the nuclei and the actin fiber network of pharyngeal carcinoma cells—Detroit-562. Materials and Methods: In order to determine the viability of the cells, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method was applied after the cells were stimulated with five concentrations of tetracycline and ampicillin (10, 25, 50, 75, and 100 μM) for 72 h. A scratch assay was used to assess the migration ability of the cells. For the visualization of the nuclei and actin fibers, 4,6-diamidino-2-phenylindole (Dapi) and Rhodamine-Phalloidin were used. Results: There are different effects of tetracycline and ampicillin. Thus, tetracycline: (i) exhibited a concentration-dependent cytotoxic effect, decreasing cell viability to approximately 46%; (ii) inhibits cellular migration up to 16% compared to 60% for control cells; and (iii) induces changes in cell morphology as well as apoptotic changes in the nucleus and F-actin fibers. In contrast, in the case of ampicillin, an increase in viability up to 113% was observed at 10 μM, while a decrease in viability up to approximately 94% was observed at the highest concentration tested (100 μM). Conclusions: The results indicated a different effect regarding the impact on pharyngeal carcinoma cells. Thus, tetracycline has a concentration-dependent cytotoxic effect, while in the case of ampicillin a slight stimulation of cell viability was observed.

Reprogramming Mitochondrial Metabolism in Synovial Macrophages of Early Osteoarthritis by a Camouflaged Meta-Defensome

Osteoarthritis (OA) is a low-grade inflammatory and progressive joint disease, and its progression is closely associated with an imbalance in M1/M2 synovial macrophages. Repolarizing pro-inflammatory M1 macrophages into the anti-inflammatory M2 phenotype is emerging as a strategy to alleviate OA progression but is compromised by unsatisfactory efficiency. In this study, the reprogramming of mitochondrial dysfunction is pioneered with a camouflaged meta-Defensome, which can transform M1 synovial macrophages into the M2 phenotype with a high efficiency of 82.3%. The meta-Defensome recognizes activated macrophages via receptor-ligand interactions and accumulates in the mitochondria through electrostatic attractions. These meta-Defensomes are macrophage-membrane-coated polymeric nanoparticles decorated with dual ligands and co-loaded with S-methylisothiourea and MnO₂ . Meta-Defensomes are demonstrated to successfully reprogram the mitochondrial metabolism of M1 macrophages by scavenging mitochondrial reactive oxygen species and inhibiting mitochondrial NO synthase, thereby increasing mitochondrial transcription factor A expression and restoring aerobic respiration. Furthermore, meta-Defensomes are intravenously injected into collagenase-induced osteoarthritis mice and effectively suppress synovial inflammation and progression of early OA, as evident from the Osteoarthritis Research Society International score. Therefore, reprogramming the mitochondrial metabolism can serve as a novel and practical approach to repolarize M1 synovial macrophages. The camouflaged meta-Defensomes are a promising therapeutic agent for impeding OA progression in tclinic.

From Foods to Chemotherapeutics: The Antioxidant Potential of Dietary Phytochemicals

Food plants have been recognized for their medicinal properties for millennia, a concept supported by epidemiological studies indicating long-term health benefits for people consuming greater amounts of fruits and vegetables. As our technology and instrumentation advance, researchers have the ability to identify promising phytochemicals, and examine their potential benefits, or detriments, to human health. While results from trials investigating single chemical supplementation have sometimes produced negative health results, studies investigating the synergistic action of phytochemicals—either within our diet or as an adjuvant to radiation or chemotherapy—appear promising. Utilizing phytochemicals as synergistic agents may lower the chemotherapeutic doses needed to incur physiological results, while also using chemicals with fewer toxic effects. This review investigates a variety of plant-produced chemicals humans typically ingest, their impacts on overall health patterns, molecular mechanisms associated with their health impacts, and the potential of their synergistic use for therapeutic purposes.

Repurposing Vitamin C for Cancer Treatment: Focus on Targeting the Tumor Microenvironment

Simple Summary

The tumor microenvironment (TME) is a complicated network, and several promising TME-targeted therapies, such as immunotherapy and targeted therapies, are now facing problems over low response rates and drug resistance. Vitamin C (VitC) has been extensively studied as a dietary nutrient and multi-targeted natural drug for fighting against tumor cells. The focus has been recently on its crucial functions in the TME. Here, we discuss the potential mechanisms of VitC in several specialized microenvironments, characterize the current status of its preclinical and clinical applications, and offer suggestions for future studies. This article is intended to provide basic researchers and clinicians with a detailed picture of VitC targeting the tumor microenvironment.

Abstract

Based on the enhanced knowledge on the tumor microenvironment (TME), a more comprehensive treatment landscape for targeting the TME has emerged. This microenvironment provides multiple therapeutic targets due to its diverse characteristics, leading to numerous TME-targeted strategies. With multifaced activities targeting tumors and the TME, vitamin C is renown as a promising candidate for combination therapy. In this review, we present new advances in how vitamin C reshapes the TME in the immune, hypoxic, metabolic, acidic, neurological, mechanical, and microbial dimensions. These findings will open new possibilities for multiple therapeutic avenues in the fight against cancer. We also review the available preclinical and clinical evidence of vitamin C combined with established therapies, highlighting vitamin C as an adjuvant that can be exploited for novel therapeutics. Finally, we discuss unresolved questions and directions that merit further investigation.

Targeting cancer stem cells with antibiotics inducing mitochondrial dysfunction as an alternative anticancer therapy

Traditional cancer treatments based on chemo- and/or radiotherapy effectively kill only differentiated cancer cells, while metastasis and recurrences are caused by surviving cancer resistant cells (CRC) or a special subpopulation of cancer cells known as cancer stem cells (CSC). Both of these cell types compromise anticancer treatment through various mechanisms, including withdrawal of the anticancer drug through ATP-binding cassette transporters, increased expression of DNA repair genes, or transition to a quiescent phenotype. In contrast to many cancers, where energy consumption is due to glycolysis (Warburg effect), the bioenergetics of CSC and CRC is most often related to oxidative phosphorylation, that is, dependent on mitochondrial function. Therefore, compounds that induce mitochondrial dysfunction (MDF), such as some antibiotics, may represent an alternative approach to anticancer therapy. This review summarizes the major recent works on the use of antibiotics to target tumors via CSC and suggests next steps for developing this approach.

A Brief look at antitumor effects of doxycycline in the treatment of colorectal cancer and combination therapies

Colorectal cancer (CRC) is considered the second most frequent cancer globally and one of the deadliest malignancies in humans. On the other hand, over time and facing the challenges of cancer treatment, several therapeutic approaches, including surgery, radiotherapy, chemotherapy, and immunotherapy, are being developed. Evidence showed that combination therapies had given relatively satisfactory clinical outcomes in inhibiting tumor progression and increasing patient survival compared with monotherapy. Among the available compounds and drugs used in chemotherapy, doxycycline, an antimicrobial drug, has been suitable for treating several malignancies such as CRC. It has been revealed that doxycycline has anti-tumor properties and can help control tumor growth in various mechanisms, such as inhibiting anti-apoptotic and angiogenic proteins. In addition, studies have shown that combination therapy with doxycycline and other anti-tumor drugs, such as doxorubicin, anti-angiogenic factors, and anti-check-point blockers, can inhibit tumor progression. Therefore, this review summarized the anti-tumor mechanisms of doxycycline in CRC treatment and related combination therapies.

Active mitochondrial respiration in cancer: a target for the drug

The relative contribution of mitochondrial respiration and subsequent energy production in malignant cells has remained controversial to date. Enhanced aerobic glycolysis and impaired mitochondrial respiration have gained more attention in the metabolic study of cancer. In contrast to the popular concept, mitochondria of cancer cells oxidize a diverse array of metabolic fuels to generate a majority of the cellular energy by respiration. Several mitochondrial respiratory chain (MRC) subunits' expressions are critical for the growth, metastasis, and cancer cell invasion. Also, the assembly factors, which regulate the integration of individual MRC complexes into native super-complexes, are upregulated in cancer. Moreover, a series of anti-cancer drugs function by inhibiting respiration and ATP production. In this review, we have specified the roles of mitochondrial fuels, MRC subunits, and super-complex assembly factors that promote active respiration across different cancer types and discussed the potential roles of MRC inhibitor drugs in controlling cancer.

Fucoidan and Alginate from the Brown Algae Colpomenia sinuosa and Their Combination with Vitamin C Trigger Apoptosis in Colon Cancer

Brown seaweeds are producers of bioactive molecules which are known to inhibit oncogenic growth. Here, we investigated the antioxidant, cytotoxic, and apoptotic effects of two polysaccharides from the brown algae Colpomenia sinuosa, namely fucoidan and alginate, in a panel of cancer cell lines and evaluated their effects when combined with vitamin C. Fucoidan and alginate were isolated from brown algae and characterized by HPLC, FTIR, and NMR spectroscopy. The results indicated that highly sulfated fucoidans had higher antioxidant and cytotoxic effects than alginate. Human colon cancer cells were the most sensitive to the algal treatments, with fucoidan having an IC50 value (618.9 µg/mL-1) lower than that of alginate (690 µg/mL-1). The production of reactive oxygen species was increased upon treatment of HCT-116 cells with fucoidan and alginate, which suggest that these compounds may trigger cell death via oxidative damage. The combination of fucoidan with vitamin C showed enhanced effects compared to treatment with fucoidan alone, as evidenced by the significant inhibitory effects on HCT-116 colon cancer cell viability. The combination of the algal polysaccharides with vitamin C caused enhanced degeneration in the nuclei of cells, as evidenced by DAPI staining and increased the subG1 population, suggesting the induction of cell death. Together, these results suggest that fucoidan and alginate from the brown algae C. sinuosa are promising anticancer compounds, particularly when used in combination with vitamin C.

High ATP Production Fuels Cancer Drug Resistance and Metastasis: Implications for Mitochondrial ATP Depletion Therapy

Recently, we presented evidence that high mitochondrial ATP production is a new therapeutic target for cancer treatment. Using ATP as a biomarker, we isolated the “metabolically fittest” cancer cells from the total cell population. Importantly, ATP-high cancer cells were phenotypically the most aggressive, with enhanced stem-like properties, showing multi-drug resistance and an increased capacity for cell migration, invasion and spontaneous metastasis. In support of these observations, ATP-high cells demonstrated the up-regulation of both mitochondrial proteins and other protein biomarkers, specifically associated with stemness and metastasis. Therefore, we propose that the “energetically fittest” cancer cells would be better able to resist the selection pressure provided by i) a hostile micro-environment and/or ii) conventional chemotherapy, allowing them to be naturally-selected for survival, based on their high ATP content, ultimately driving tumor recurrence and distant metastasis. In accordance with this energetic hypothesis, ATP-high MDA-MB-231 breast cancer cells showed a dramatic increase in their ability to metastasize in a pre-clinical model in vivo. Conversely, metastasis was largely prevented by treatment with an FDA-approved drug (Bedaquiline), which binds to and inhibits the mitochondrial ATP-synthase, leading to ATP depletion. Clinically, these new therapeutic approaches could have important implications for preventing treatment failure and avoiding cancer cell dormancy, by employing ATP-depletion therapy, to target even the fittest cancer cells.

High-dose intravenous vitamin C, a promising multi-targeting agent in the treatment of cancer

Mounting evidence indicates that vitamin C has the potential to be a potent anti-cancer agent when administered intravenously and in high doses (high-dose IVC). Early phase clinical trials have confirmed safety and indicated efficacy of IVC in eradicating tumour cells of various cancer types. In recent years, the multi-targeting effects of vitamin C were unravelled, demonstrating a role as cancer-specific, pro-oxidative cytotoxic agent, anti-cancer epigenetic regulator and immune modulator, reversing epithelial-to-mesenchymal transition, inhibiting hypoxia and oncogenic kinase signalling and boosting immune response. Moreover, high-dose IVC is powerful as an adjuvant treatment for cancer, acting synergistically with many standard (chemo-) therapies, as well as a method for mitigating the toxic side-effects of chemotherapy. Despite the rationale and ample evidence, strong clinical data and phase III studies are lacking. Therefore, there is a need for more extensive awareness of the use of this highly promising, non-toxic cancer treatment in the clinical setting. In this review, we provide an elaborate overview of pre-clinical and clinical studies using high-dose IVC as anti-cancer agent, as well as a detailed evaluation of the main known molecular mechanisms involved. A special focus is put on global molecular profiling studies in this respect. In addition, an outlook on future implications of high-dose vitamin C in cancer treatment is presented and recommendations for further research are discussed.

Pan-Cancer Analysis of Glycolytic and Ketone Bodies Metabolic Genes: Implications for Response to Ketogenic Dietary Therapy

Background

The Warburg effect, also termed "aerobic glycolysis", is one of the most remarkable and ubiquitous metabolic characteristics exhibited by cancer cells, representing a potential vulnerability that might be targeted for tumor therapy. Ketogenic diets (KDs), composed of high-fat, moderate-protein and low carbohydrates, are aimed at targeting the Warburg effect for cancer treatment, which have recently gained considerable attention. However, the efficiency of KDs was inconsistent, and the genotypic contribution is still largely unknown.

Methods

The bulk RNA-seq data from The Cancer Genome Atlas (TCGA), single cell RNA sequencing (scRNA-seq), and microarray data from Gene Expression Omnibus (GEO) and Cancer Cell Line Encyclopedia (CCLE) were collected. A joint analysis of glycolysis and ketone bodies metabolism (KBM) pathway was performed across over 10,000 tumor samples and nearly 1,000 cancer cell lines. A series of bioinformatic approaches were combined to identify a metabolic subtype that may predict the response to ketogenic dietary therapy (KDT). Mouse xenografts were established to validate the predictive utility of our subtypes in response to KDT.

Results

We first provided a system-level view of the expression pattern and prognosis of the signature genes from glycolysis and KBM pathway across 33 cancer types. Analysis by joint stratification of glycolysis and KBM revealed four metabolic subtypes, which correlated extensively but diversely with clinical outcomes across cancers. The glycolytic subtypes may be driven by TP53 mutations, whereas the KB-metabolic subtypes may be mediated by CTNNB1 (β-catenin) mutations. The glycolytic subtypes may have a better response to KDs compared to the other three subtypes. We preliminarily confirmed the idea by literature review and further performed a proof-of-concept experiment to validate the predictive value of the metabolic subtype in liver cancer xenografts.

Conclusions

Our findings identified a metabolic subtype based on glycolysis and KBM that may serve as a promising biomarker to predict the clinical outcomes and therapeutic responses to KDT.

Doxycycline Attenuates Cancer Cell Growth by Suppressing NLRP3-Mediated Inflammation

NLR family pyrin domain containing 3 (NLRP3) inflammasome formation is triggered by the damaged mitochondria releasing reactive oxygen species. Doxycycline was shown to regulate inflammation; however, its effect on NLRP3 in cancer remains largely unknown. Therefore, we sought to determine the effect of doxycycline on NLRP3 regulation in cancer using an in vitro model. NLRP3 was activated in a prostate cancer cell line (PC3) and a lung cancer cell line (A549) before treatment with doxycycline. Inflammasome activation was assessed by analyzing RNA expression of NLRP3, Pro-CASP-1, and Pro-IL1β using RT-qPCR. Additionally, NLPR3 protein expression and IL-1β secretion were analyzed using Western blot and ELISA, respectively. Tumor cell viability was determined using Annexin V staining and a cell proliferation assay. Cytokine secretion was analyzed using a 41Plex assay for human cytokines. Data were analyzed using one-way ANOVA model with Tukey’s post hoc tests. Doxycycline treatment decreased NLRP3 formation in PC3 and A549 cells compared to untreated and LPS only treated cells (p < 0.05). Doxycycline also decreased proliferation and caused cell death through apoptosis, a response that differed to the LPS-Nigericin mediated pyroptosis. Our findings suggest that doxycycline inhibits LPS priming of NLRP3 and reduces tumor progression through early apoptosis in cancer.

One-Step Biosynthesis of Vitamin C in Saccharomyces cerevisiae

Vitamin C (VC) is comprehensively applied in foods, cosmetics, pharmaceuticals, and especially clinical medicine. Nowadays, the industrial production of VC mainly relies on the classic two-step fermentation route, and researchers have explored the way for one-step fermentation of VC in recent years. In this study, a VC biosynthesis pathway that directly produced VC from glucose was reconstructed in Saccharomyces cerevisiae, and the protein engineering and metabolic engineering strategies were adopted to improve it. First, five exogenous modules from Arabidopsis were introduced into the chassis cells by synthetic biology approaches to obtain the strain YLAA harboring VC biosynthesis. In addition, L-galactose dehydrogenase (L-GalDH) and L-galactono-1,4-lactone dehydrogenase (L-GLDH) were fused and expressed in S. cerevisiae cells for the first time, which increased the intracellular VC accumulation by 2.78-fold, reaching 9.97 ± 0.09 mg/L. Through copy number engineering, it was further confirmed that the last step catalyzed by L-GLDH is the rate-limiting step. GDP-L-galactose phosphorylase (GPP) encoded by vtc2 is another rate-limiting enzyme confirmed by GAL1p overexpression results. Finally, by balancing gene expression and cell growth, the highest production strain with overexpressing vtc2 by multicopy plasmids was constructed. The VC accumulation reached 24.94 ± 1.16 mg/L, which was currently the highest production from glucose in S. cerevisiae. The production of the recombinant strain reached nearly 44 mg/L with the exogenous addition of L-galactose or glutathione. The results further emphasized the importance of the step catalyzed by GPP. The investigation provided experience for the efficient biosynthesis of VC and the determination of rate-limiting steps.

Effect of chemically modified tetracycline-8 (CMT-8) on hematology, blood chemistry, cytokines and peripheral blood lymphocyte subsets of healthy dogs

Tetracyclines are antibiotics widely used in human and veterinary medicine. Effects on the immune system and inflammatory response, including effects on blood leukocytes proliferation and function and in cytokines synthesis, have been described. Chemically modified tetracyclines (CMT) have lost their antimicrobial activity, but maintain these other properties. This study analyzes the effect of chemically modified tetracycline-8 (CMT-8) on the evolution of complete blood count, blood chemistry, the mRNA expression of selected cytokines and peripheral blood lymphocyte subpopulations distribution in healthy dogs. CMT-8 at a dose of 10 mg/kg once daily was administered per os to six healthy dogs. A control group of five healthy dogs, living in the same conditions than dogs treated with CMT-8, received placebo with an identical therapeutic regimen. When given at the doses used in this study, no side effects of CMT-8 were detected, suggesting a good tolerance and a limited toxicity of the drug. Dogs treated with CMT-8 showed a gradual increase in mean corpuscular hemoglobin. The administration of CMT-8 in healthy dogs did not affect blood mRNA expression of IFN-γ, TNFα, IL-4, IL-6, IL-10, IL-12 p40 and IL-13. However, the lymphocytes expressing class II MHC on their surface decreased during the first two weeks of CMT-8 treatment and subsequently increased for the next three months. Considering the absence of antimicrobial properties of the drug, the effects of CMT-8 detected in this study seem to be unrelated to the classical antimicrobial activity attributed to tetracyclines.

Antioxidants for the Treatment of Breast Cancer: Are We There Yet?

Breast cancer is the most frequent cancer and the leading cause of cancer death in women. Oxidative stress and the generation of reactive oxygen species (ROS) have been related to cancer progression. Compared to their normal counterparts, tumor cells show higher ROS levels and tight regulation of REDOX homeostasis to maintain a low degree of oxidative stress. Traditionally antioxidants have been extensively investigated to counteract breast carcinogenesis and tumor progression as chemopreventive agents; however, there is growing evidence indicating their potential as adjuvants for the treatment of breast cancer. Aimed to elucidate whether antioxidants could be a reality in the management of breast cancer patients, this review focuses on the latest investigations regarding the ambivalent role of antioxidants in the development of breast cancer, with special attention to the results derived from clinical trials, as well as their potential use as plausible agents in combination therapy and their power to ameliorate the side effects attributed to standard therapeutics. Data retrieved herein suggest that antioxidants play an important role in breast cancer prevention and the improvement of therapeutic efficacy; nevertheless, appropriate patient stratification based on "redoxidomics" or tumor subtype is mandatory in order to define the dosage for future standardized and personalized treatments of patients.

Reasoned therapeutic protocol in outpatients with COVID-19

BACKGROUND

Seventy percent of patients affected by SARS-COV-2 disease are asymptomatic or with symptoms that not required Hospitalization. A prodromal period lasting about 5 days can be identified. In this phase a patient with a positive swab for viral RNA may or may not evolve towards the phase of symptomatic disease.

METHODS

In this paper we reviewed the literature related to COVID-19 therapy we propose a reasoned treatment protocols in outpatients according to the age and the comorbidity.

RESULTS

The aim of this study was to reduce the impact of the virus by reducing its ability to attack cells and the inflammatory burden and the prothrombotic effects proposing two therapeutic schemes of proven efficacy according to the age of the patients and the comorbidities.

CONCLUSIONS

We aimed to reduce worsening of clinical status and hospitalization while protecting patients at home.

The role of hypoxia in the tumor microenvironment and development of cancer stem cell: a novel approach to developing treatment

Hypoxia is a common feature of solid tumors, and develops because of the rapid growth of the tumor that outstrips the oxygen supply, and impaired blood flow due to the formation of abnormal blood vessels supplying the tumor. It has been reported that tumor hypoxia can: activate angiogenesis, thereby enhancing invasiveness and risk of metastasis; increase survival of tumor, as well as suppress anti-tumor immunity and hamper the therapeutic response. Hypoxia mediates these effects by several potential mechanisms: altering gene expression, the activation of oncogenes, inactivation of suppressor genes, reducing genomic stability and clonal selection. We have reviewed the effects of hypoxia on tumor biology and the possible strategiesto manage the hypoxic tumor microenvironment (TME), highlighting the potential use of cancer stem cells in tumor treatment.

Antitumor Drugs and Their Targets

Through novel methodologies, including both basic and clinical research, progress has been made in the therapy of solid cancer. Recent innovations in anticancer therapies, including immune checkpoint inhibitor biologics, therapeutic vaccines, small drugs, and CAR-T cell injections, mark a new epoch in cancer research, already known for faster (epi-)genomics, transcriptomics, and proteomics. As the long-sought after personalization of cancer therapies comes to fruition, the need to evaluate all current therapeutic possibilities and select the best for each patient is of paramount importance. This is a novel task for medical care that deserves prominence in therapeutic considerations in the future. This is because cancer is a complex genetic disease. In its deadly form, metastatic cancer, it includes altered genes (and their regulators) that encode ten hallmarks of cancer-independent growth, dodging apoptosis, immortalization, multidrug resistance, neovascularization, invasiveness, genome instability, inflammation, deregulation of metabolism, and avoidance of destruction by the immune system. These factors have been known targets for many anticancer drugs and treatments, and their modulation is a therapeutic goal, with the hope of rendering solid cancer a chronic rather than deadly disease. In this article, the current therapeutic arsenal against cancers is reviewed with a focus on immunotherapies.

Advance in metabolism and target therapy in breast cancer stem cells

Breast cancer, like many other cancers, is believed to be driven by a population of cells that display stem cell properties. Recent studies suggest that cancer stem cells (CSCs) are essential for tumor progression, and tumor relapse is thought to be caused by the presence of these cells. CSC-targeted therapies have also been proposed to overcome therapeutic resistance in breast cancer after the traditional therapies. Additionally, the metabolic properties of cancer cells differ markedly from those of normal cells. The efficacy of metabolic targeted therapy has been shown to enhance anti-cancer treatment or overcome therapeutic resistance of breast cancer cells. Metabolic targeting of breast CSCs (BCSCs) may be a very effective strategy for anti-cancer treatment of breast cancer cells. Thus, in this review, we focus on discussing the studies involving metabolism and targeted therapy in BCSCs.

Mitochondrial Fission Factor (MFF) Inhibits Mitochondrial Metabolism and Reduces Breast Cancer Stem Cell (CSC) Activity

Elevated mitochondrial biogenesis and metabolism represent key features of breast cancer stem cells (CSCs), whose propagation is conducive to disease onset and progression. Therefore, interfering with mitochondria biology and function may be regarded as a useful approach to eradicate CSCs. Here, we used the breast cancer cell line MCF7 as a model system to interrogate how mitochondrial fission contributes to the development of mitochondrial dysfunction toward the inhibition of metabolic flux and stemness. We generated an isogenic MCF7 cell line transduced with Mitochondrial Fission Factor (MCF7-MFF), which is primarily involved in mitochondrial fission. We evaluated the biochemical, molecular and functional properties of MCF7-MFF cells, as compared to control MCF7 cells transduced with the empty vector (MCF7-Control). We observed that MFF over-expression reduces both mitochondrial mass and activity, as evaluated using the mitochondrial probes MitroTracker Red and MitoTracker Orange, respectively. The analysis of metabolic flux using the Seahorse XFe96 revealed the inhibition of OXPHOS and glycolysis in MCF7-MFF cells, suggesting that increased mitochondrial fission may impair the biochemical properties of these organelles. Notably, CSCs activity, assessed by 3D-tumorsphere assays, was reduced in MCF7-MFF cells. A similar trend was observed for the activity of ALDH, a well-established marker of stemness. We conclude that enhanced mitochondrial fission may compromise CSCs propagation, through the impairment of mitochondrial function, possibly leading to a quiescent cell phenotype. Unbiased proteomic analysis revealed that proteins involved in mitochondrial dysfunction, oxidative stress-response, fatty acid metabolism and hypoxia signaling are among the most highly up-regulated in MCF7-MFF cells. Of note, integrated analysis of top regulatory networks obtained from unbiased proteomics in MCF7-MFF cells predicts that this cell phenotype activates signaling systems and effectors involved in the inhibition of cell survival and adhesion, together with the activation of specific breast cancer cell death programs. Overall, our study shows that unbalanced and abnormal activation of mitochondrial fission may drive the impairment of mitochondrial metabolic function, leading to inhibition of CSC propagation, and the activation of quiescence programs. Exploiting the potential of mitochondria to control pivotal events in tumor biology may, therefore, represent a useful tool to prevent disease progression.

Association of vitamin C intake with breast cancer risk and mortality: a meta-analysis of observational studies

The association between vitamin C intake and breast cancer is unclear. This meta-analysis aimed to precisely assess the association of vitamin C intake with breast cancer risk and mortality. We searched the PubMed, Embase, and Web of Science databases up to June 2020 and found 69 studies relevant to breast cancer risk (54 studies) and survival (15 studies). Relative risks and 95% confidence intervals were calculated using the random-effects models. Pooled results suggested that the highest versus lowest vitamin C intake was significantly associated with a lower risk of breast cancer incidence (Relative Risk = 0.86; 95% confidence interval, 0.81-0.92). Dietary vitamin C but not supplements was found to reduce breast cancer risk (Relative Risk = 0.89; 95% confidence interval, 0.82-0.96). For the highest versus lowest vitamin C intake, the pooled hazard risk for breast cancer-specific mortality was 0.78 (95% confidence interval, 0.69-0.88), totality mortality was 0.82 (95% confidence interval, 0.74-0.91), and recurrence was 0.81 (95% confidence interval, 0.67-0.99). Our analysis suggests that higher vitamin C intake is significantly associated with reduced breast cancer incidence and mortality. However, the intake of vitamin C supplements has no significant effect on breast cancer prevention.

The Metabolic Heterogeneity and Flexibility of Cancer Stem Cells

Simple Summary

Cancer stem cells (CSCs) have been shown to be the main cause of therapy resistance and cancer recurrence. An analysis of their biological properties has revealed that CSCs have a particular metabolism that differs from non-CSCs to maintain their stemness properties. In this review, we analyze the flexible metabolic mechanisms of CSCs and highlight the new therapeutics that target CSC metabolism.

Abstract

Numerous findings have indicated that CSCs, which are present at a low frequency inside primary tumors, are the main cause of therapy resistance and cancer recurrence. Although various therapeutic methods targeting CSCs have been attempted for eliminating cancer cells completely, the complicated characteristics of CSCs have hampered such attempts. In analyzing the biological properties of CSCs, it was revealed that CSCs have a peculiar metabolism that is distinct from non-CSCs to maintain their stemness properties. The CSC metabolism involves not only the catabolic and anabolic pathways, but also intracellular signaling, gene expression, and redox balance. In addition, CSCs can reprogram their metabolism to flexibly respond to environmental changes. In this review, we focus on the flexible metabolic mechanisms of CSCs, and highlight the new therapeutics that target CSC metabolism.

Pyridoxine induces monocyte-macrophages death as specific treatment of acute myeloid leukemia

Acute myeloid leukemia (AML) is an aggressive hematological malignancy that gradually develops resistance to current chemotherapy treatments. The available chemotherapy drugs show serious non-specific cytotoxicity to healthy normal cells, resulting in relapse and low survival rates. Natural small molecules with less toxicity and high selectivity for AML are urgently needed. In this study, we confirmed that pyridoxine (vitamin B6) selectively induces monocyte macrophages to undergo programmed cell death in two different modes: caspase-3-dependent apoptosis in U937 cells or GSDME-mediated pyroptosis in THP-1 cells. Further molecular analysis indicated that blocking the caspase pathway could switch the death to MLKL-dependent necroptosis and subsequent extensive inflammatory response. Pyridoxine also delayed the disease progression in a THP-1 leukemia mouse model. In addition, it induced the death of primary AML cells from AML patients by activating caspase-8/3. Overall, our results identify pyridoxine, a low-toxicity natural small molecule, as a potential therapeutic drug for AML treatment.

Synthesis and Antitumor Activity of Doxycycline Polymeric Nanoparticles: Effect on Tumor Apoptosis in Solid Ehrlich Carcinoma

Objectives: The aim of this study was to prepare doxycycline polymeric nanoparticles (DOXY-PNPs) with hope to enhance its chemotherapeutic potential against solid Ehrlich carcinoma (SEC). Methods: Three DOXY-PNPs were formulated by nanoprecipitation method using hydroxypropyl methyl cellulose (HPMC) as a polymer. The prepared DOXY-PNPs were evaluated for the encapsulation efficiency (EE%), the drug loading capacity, particle size, zeta potential (ZP) and the in-vitro release for selection of the best formulation. PNP number 3 was selected for further biological testing based on the best pharmaceutical characters. PNP3 (5 and 10 mg/kg) was evaluated for the antitumor potential against SEC grown in female mice by measuring the tumor mass as well as the expression and immunohistochemical staining for the apoptosis markers; caspase 3 and BAX. Results: The biological study documented the greatest reduction in tumor mass in mice treated with PNP3. Importantly, treatment with 5 mg/kg of DOXY-PNPs produced a similar chemotherapeutic effect to that produced by 10 mg/kg of free DOXY. Further, a significant elevation in mRNA expression and immunostaining for caspase 3 and BAX was detected in mice group treated with DOXY-PNPs. Conclusions: The DOXY-PNPs showed greater antitumor potential against SEC grown in mice and greater values for Spearman’s correlation coefficients were detected when correlation with tumor mass or apoptosis markers was examined; this is in comparison to free DOXY. Hence, DOXY-PNPs should be tested in other tumor types to further determine the utility of the current technique in preparing chemotherapeutic agents and enhancing their properties.

Role of Mitochondria in Cancer Stem Cell Resistance

Cancer stem cells (CSC) are associated with the mechanisms of chemoresistance to different cytotoxic drugs or radiotherapy, as well as with tumor relapse and a poor prognosis. Various studies have shown that mitochondria play a central role in these processes because of the ability of this organelle to modify cell metabolism, allowing survival and avoiding apoptosis clearance of cancer cells. Thus, the whole mitochondrial cycle, from its biogenesis to its death, either by mitophagy or by apoptosis, can be targeted by different drugs to reduce mitochondrial fitness, allowing for a restored or increased sensitivity to chemotherapeutic drugs. Once mitochondrial misbalance is induced by a specific drug in any of the processes of mitochondrial metabolism, two elements are commonly boosted: an increment in reactive nitrogen/oxygen species and, subsequently, activation of the intrinsic apoptotic pathway.

Two Faces of Vitamin C-Antioxidative and Pro-Oxidative Agent

Vitamin C has been known for decades. It is common in everyday use as an element of the diet, supplementation, and a preservative. For years, research has been conducted to precisely determine the mechanism of action of ascorbate in the cell. Available results indicate its multi-directional cellular effects. Vitamin C, which belongs to antioxidants scavenging free radicals, also has a ‘second face’—as a pro-oxidative factor. However, whether is the latter nature a defect harmful to the cell, or whether a virtue that is a source of benefit? In this review, we discuss the effects of vitamin C treatment in cancer prevention and the role of ascorbate in maintaining redox balance in the central nervous system (CNS). Finally, we discuss the effect of vitamin C supplementation on biomarkers of oxidative DNA damage and review the evidence that vitamin C has radioprotective properties.

Repurposing of drugs: An attractive pharmacological strategy for cancer therapeutics

Human malignancies are one of the major health-related issues though out the world and anticipated to rise in the future. The development of novel drugs/agents requires a huge amount of cost and time that represents a major challenge for drug discovery. In the last three decades, the number of FDA approved drugs has dropped down and this led to increasing interest in drug reposition or repurposing. The present review focuses on recent concepts and therapeutic opportunities for the utilization of antidiabetics, antibiotics, antifungal, anti-inflammatory, antipsychotic, PDE inhibitors and estrogen receptor antagonist, Antabuse, antiparasitic and cardiovascular agents/drugs as an alternative approach against human malignancies. The repurposing of approved non-cancerous drugs is an effective strategy to develop new therapeutic options for the treatment of cancer patients at an affordable cost in clinics. In the current scenario, most of the countries throughout the globe are unable to meet the medical needs of cancer patients because of the high cost of the available cancerous drugs. Some of these drugs displayed potential anti-cancer activity in preclinic and clinical studies by regulating several key molecular mechanisms and oncogenic pathways in human malignancies. The emerging pieces of evidence indicate that repurposing of drugs is crucial to the faster and cheaper discovery of anti-cancerous drugs.

Targeting cancer stem cells from a metabolic perspective

The process of cancer development and progression is driven by distinct subsets of cancer stem cells (CSCs) that contribute the self-renewal capacity as the major impetus to the metastatic dissemination and main impediments in cancer treatment. Given that CSCs are so scarce in the tumor mass, there are debatable points on the metabolic signatures of CSCs. As opposed to differentiated tumor progenies, CSCs display exquisite patterns of metabolism that, depending on the type of cancer, predominately rely on glycolysis, oxidative metabolism of glutamine, fatty acids, or amino acids for ATP production. Metabolic heterogeneity of CSCs, which attributes to differences in type and microenvironment of tumors, confers CSCs to have the plasticity to cope with the endogenous mitochondrial stress and exogenous microenvironment. In essence, CSCs and normal stem cells are like mirror images of each other in terms of metabolism. To achieve reprogramming, CSCs not only need to upregulate their metabolic engine for self-renewal and defense mechanism, but also expedite the antioxidant defense to sustain the redox homeostasis. In the context of these pathways, this review portrays the connection between the metabolic features of CSCs and cancer stemness. Identification of the metabolic features in conferring resistance to anticancer treatment dictated by CSCs can enhance the opportunity to open up a new therapeutic dimension, which might not only improve the effectiveness of cancer therapies but also annihilate the whole tumor without recurrence. Henceforth, we highlight current findings of potential therapeutic targets for the design of alternative strategies to compromise the growth, drug resistance, and metastasis of CSCs by altering their metabolic phenotypes. Perturbing the versatile skills of CSCs by barricading metabolic signaling might bring about plentiful approaches to discover novel therapeutic targets for clinical application in cancer treatments.

Impact statement

This minireview highlights the current evidence on the mechanisms of pivotal metabolic pathways that attribute to cancer stem cells (CSCs) with a special focus on developing metabolic strategies of anticancer treatment that can be exploited in preclinical and clinical settings. Specific metabolic inhibitors that can overwhelm the properties of CSCs may impede tumor recurrence and metastasis, and potentially achieve a permanent cure of cancer patients.

Combination Therapy with Vitamin C Could Eradicate Cancer Stem Cells

Cancer remains one of the most feared and dreaded diseases in this era of modern medicine, claiming the lives of many, and affecting the quality of life of several others around the globe despite major advances in the diagnosis, treatment, palliative care and the immense resources invested into cancer research. While research in cancer has largely focused on the neoplasm/tumor and the cancerous cells that make up the tumor, more recently, the existence, proliferation, differentiation, migration and invasion of cancer stem cells (CSCs) and the role that CSCs play in tumor initiation, progression, metastasis, drug resistance and relapse/recurrence of the disease has gained widespread interest in cancer research. Although the conventional therapeutic approaches such as surgery, chemotherapy and radiation therapy are effective cancer treatments, very often these treatment modalities fail to target the CSCs, which then later become the source of disease recurrence. A majority of the anti-cancer agents target rapidly dividing cancer cells and normal cells and hence, have side effects that are not expected. Targeting CSCs remains a challenge due to their deviant nature with a low proliferation rate and increased drug resistance mechanism. Ascorbic acid/Vitamin C (Vit.C), a potent antioxidant, is a cofactor for several biosynthetic and gene regulatory enzymes and a vital contributor to immune defense of the body, and was found to be deficient in patients with advanced stages of cancer. Vit.C has gained importance in the treatment of cancer due to its ability to modulate the redox status of the cell and influence epigenetic modifications and significant roles in HIF1α signaling. Studies have reported that intravenous administration of Vit.C at pharmacological doses selectively kills tumor cells and targets CSCs when administered along with chemotherapeutic drugs. In the current article, we provide an in-depth review of how Vit.C plays an important role in targeting CSCs and its possible use as an adjuvant, neoadjuvant or co-treatment in the treatment of cancers.

Pro- and Antioxidant Effects of Vitamin C in Cancer in correspondence to Its Dietary and Pharmacological Concentrations

Vitamin C is an antioxidant that may scavenge reactive oxygen species preventing DNA damage and other effects important in cancer transformation. Dietary vitamin C from natural sources is taken with other compounds affecting its bioavailability and biological effects. High pharmacological doses of vitamin C may induce prooxidant effects, detrimental for cancer cells. An oxidized form of vitamin C, dehydroascorbate, is transported through glucose transporters, and cancer cells switch from oxidative phosphorylation to glycolysis in energy production so an excess of vitamin C may limit glucose transport and ATP production resulting in energetic crisis and cell death. Vitamin C may change the metabolomic and epigenetic profiles of cancer cells, and activation of ten-eleven translocation (TET) proteins and downregulation of pluripotency factors by the vitamin may eradicate cancer stem cells. Metastasis, the main reason of cancer-related deaths, requires breakage of anatomical barriers containing collagen, whose synthesis is promoted by vitamin C. Vitamin C induces degradation of hypoxia-inducible factor, HIF-1, essential for the survival of tumor cells in hypoxic conditions. Dietary vitamin C may stimulate the immune system through activation of NK and T cells and monocytes. Pharmacological doses of vitamin C may inhibit cancer transformation in several pathways, but further studies are needed to address both mechanistic and clinical aspects of this effect.

The ER-alpha mutation Y537S confers Tamoxifen-resistance via enhanced mitochondrial metabolism, glycolysis and Rho-GDI/PTEN signaling: Implicating TIGAR in somatic resistance to endocrine therapy

Naturally-occurring somatic mutations in the estrogen receptor gene (ESR1) have been previously implicated in the clinical development of resistance to hormonal therapies, such as Tamoxifen. For example, the somatic mutation Y537S has been specifically associated with acquired endocrine resistance. Briefly, we recombinantly-transduced MCF7 cells with a lentiviral vector encoding ESR1 (Y537S). As a first step, we confirmed that MCF7-Y537S cells are indeed functionally resistant to Tamoxifen, as compared with vector alone controls. Importantly, further phenotypic characterization of Y537S cells revealed that they show increased resistance to Tamoxifen-induced apoptosis, allowing them to form mammospheres with higher efficiency, in the presence of Tamoxifen. Similarly, Y537S cells had elevated basal levels of ALDH activity, a marker of “stemness”, which was also Tamoxifen-resistant. Metabolic flux analysis of Y537S cells revealed a hyper-metabolic phenotype, with significantly increased mitochondrial respiration and high ATP production, as well as enhanced aerobic glycolysis. Finally, to understand which molecular signaling pathways that may be hyper-activated in Y537S cells, we performed unbiased label-free proteomics analysis. Our results indicate that TIGAR over-expression and the Rho-GDI/PTEN signaling pathway appear to be selectively activated by the Y537S mutation. Remarkably, this profile is nearly identical in MCF7-TAMR cells; these cells were independently-generated in vitro, suggesting a highly conserved mechanism underlying Tamoxifen-resistance. Importantly, we show that the Y537S mutation is specifically associated with the over-expression of a number of protein markers of poor clinical outcome (COL6A3, ERBB2, STAT3, AFP, TFF1, CDK4 and CD44). In summary, we have uncovered a novel metabolic mechanism leading to endocrine resistance, which may have important clinical implications for improving patient outcomes.