Sodium Butyrate Selectively Kills Cancer Cells and Inhibits Migration in Colorectal Cancer by Targeting Thioredoxin-1

Sodium butyrate blocks the growth of colorectal cancer by inhibiting the aerobic glycolysis mediated by SIRT4/HIF-1α

The prevalence and mortality rates of colorectal cancer have been increasing in recent years, driven in part by the reliance of cancerous cells on aerobic glycolysis for growth. Sodium butyrate (NaB) has been shown to impede this process in colorectal cancer cells, although its mechanism of action remains unclear. In this study, we used cobalt chloride (CoCl2) to simulate a hypoxic environment and demonstrated that NaB downregulated hypoxia-inducible factor-1α (HIF-1α) protein levels under both normoxic and hypoxic conditions. By employing cycloheximide (CHX), MG132, and chloroquine (CQ), we investigated whether NaB affects HIF-1α protein levels via the autophagy pathway. Importantly, siRNA-mediated SIRT4 knockdown revealed that NaB promotes HIF-1α autophagic degradation by upregulating SIRT4 expression. This subsequently inhibits HIF-1α-mediated expression of GLUT1 and LDHA, reducing glucose uptake, lactate production, and ATP generation, ultimately suppressing aerobic glycolysis and cell proliferation in colorectal cancer cells. Furthermore, a human colorectal cancer xenograft model confirmed that butyric acid inhibited tumor growth in vivo, correlating with SIRT4 and HIF-1α modulation. In conclusion, our findings indicate that NaB hinders colorectal cancer progression by disrupting aerobic glycolysis mediated by SIRT4/HIF-1α.

Effect of Butyrate on Food-Grade Titanium Dioxide Toxicity in Different Intestinal In Vitro Models

Short-chain fatty acids (SCFA) are an important energy source for colonocytes and crucial messenger molecules both locally in the intestine and systemically. Butyrate, one of the most prominent and best-studied SCFA, was demonstrated to exert anti-inflammatory effects, improve barrier integrity, enhance mucus synthesis in the intestine, and promote cell differentiation of intestinal epithelial cells in vitro. While the physiological relevance is undisputed, it remains unclear if and to what extent butyrate can influence the effects of xenobiotics, such as food-grade titanium dioxide (E171, fgTiO2), in the intestine. TiO2 has been controversially discussed for its DNA-damaging potential and banned as a food additive within the European Union (EU) since 2022. First, we used enterocyte Caco-2 monocultures to test if butyrate affects the cytotoxicity and inflammatory potential of fgTiO2 in a pristine state or following pretreatment under simulated gastric and intestinal pH conditions. We then investigated pretreated fgTiO2 in intestinal triple cultures of Caco-2, HT29-MTX-E12, and THP-1 cells in homeostatic and inflamed-like state for cytotoxicity, barrier integrity, cytokine release as well as gene expression of mucins, oxidative stress markers, and DNA repair. In Caco-2 monocultures, butyrate had an ambivalent role: pretreated but not pristine fgTiO2 induced cytotoxicity in Caco-2 cells, which was not observed in the presence of butyrate. Conversely, fgTiO2 induced the release of interleukin 8 in the presence but not in the absence of butyrate. In the advanced in vitro models, butyrate did not affect the characteristics of the healthy or inflamed states and caused negligible effects in the investigated end points following fgTiO2 exposure. Taken together, the effects of fgTiO2 strongly depend on the applied testing approach. Our findings underline the importance of the experimental setup, including the choice of in vitro model and the physiological relevance of the exposure scenario, for the hazard testing of food-grade pigments like TiO2.

Exploring the Thioredoxin System as a Therapeutic Target in Cancer: Mechanisms and Implications

Cells constantly face the challenge of managing oxidants. In aerobic organisms, oxygen (O2) is used for energy production, generating reactive oxygen species (ROS) as byproducts of enzymatic reactions. To protect against oxidative damage, cells possess an intricate system of redox scavengers and antioxidant enzymes, collectively forming the antioxidant defense system. This system maintains the redox equilibrium and enables the generation of localized oxidative signals that regulate essential cellular functions. One key component of this defense is the thioredoxin (Trx) system, which includes Trx, thioredoxin reductase (TrxR), and NADPH. The Trx system reverses oxidation of macromolecules and indirectly neutralizes ROS via peroxiredoxin (Prx). This dual function protects cells from damage accumulation and supports physiological cell signaling. However, the Trx system also shields tumors from oxidative damage, aiding their survival. Due to elevated ROS levels from their metabolism, tumors often rely on the Trx system. In addition, the Trx system regulates critical pathways such as proliferation and neoangiogenesis, which tumors exploit to enhance growth and optimize nutrient and oxygen supply. Consequently, the Trx system is a potential target for cancer therapy. The challenge lies in selectively targeting malignant cells without disrupting the redox equilibrium in healthy cells. The aim of this review article is threefold: first, to elucidate the function of the Trx system; second, to discuss the Trx system as a potential target for cancer therapies; and third, to present the possibilities for inhibiting key components of the Trx system, along with an overview of the latest clinical studies on these inhibitors.

From Crypts to Cancer: A Holistic Perspective on Colorectal Carcinogenesis and Therapeutic Strategies

Colorectal cancer (CRC) represents a significant global health burden, with high incidence and mortality rates worldwide. Recent progress in research highlights the distinct clinical and molecular characteristics of colon versus rectal cancers, underscoring tumor location's importance in treatment approaches. This article provides a comprehensive review of our current understanding of CRC epidemiology, risk factors, molecular pathogenesis, and management strategies. We also present the intricate cellular architecture of colonic crypts and their roles in intestinal homeostasis. Colorectal carcinogenesis multistep processes are also described, covering the conventional adenoma-carcinoma sequence, alternative serrated pathways, and the influential Vogelstein model, which proposes sequential APC, KRAS, and TP53 alterations as drivers. The consensus molecular CRC subtypes (CMS1-CMS4) are examined, shedding light on disease heterogeneity and personalized therapy implications.

Thioredoxin system in colorectal cancer: Its role in carcinogenesis, disease progression, and response to treatment

The thioredoxin system is essential for many physiological processes, including the maintenance of redox signalling pathways. Alterations in the activity, expression and interactions with other signalling pathways can lead to protective or pathophysiological responses. Thioredoxin and thioredoxin reductase, the two main components of this system, are often overexpressed in cancer, including colorectal cancer. This overexpression is often linked with tumour progression and poor outcomes. This review discusses the role of the Trx system in driving colorectal carcinogenesis and disease progression, as well as the challenges of targeting this system. Additionally, the recent advancements in the development of novel and effective thioredoxin inhibitors for colorectal cancer are also explored.

Potential antitumor effects of short-chain fatty acids in breast cancer models

The effects of short-chain fatty acids (SCFAs) have been explored against cancer due to the crosstalk between gut microbiota alterations and the immune system as a crucial role in cancer development. We evaluated the SCFAs effects in both in vitro and in vivo breast cancer models. In vitro, the SCFAs displayed contrasting effects on viability index, according to the evaluation of breast cancer cells with different phenotypes, human MCF-7, SK-BR-3, MDA-MD-231, or the mouse 4T1 lineage. Acetate displayed minimal effects at concentrations up to 100 mM. Alternatively, propionate increases or reduces cell viability depending on the concentration. Butyrate and valerate showed consistent time- and concentration-dependent effects on the viability of human or mouse breast cancer cells. The selective FFA2 4-CMTB or FFA3 AR420626 receptor agonists failed to overtake the SCFA actions, except by modest inhibitory effects on MDA-MB-231 and 4T1 cell viability. The FFA2 CATPB or FFA3 and β-hydroxybutyrate receptor antagonists lacked significant activity on human cell lines, although CATPB reduced 4T1 cell viability. Butyrate significantly affected cell morphology, clonogenicity, and migration, according to the evaluation of MDA-MB-231 and 4T1 cells. A preliminary examination of in vivo oral effects of butyrate, propionate, or valerate, dosed in prophylactic or therapeutic regimens, on several parameters evaluated in an orthotopic breast cancer model showed a reduction of lung metastasis in post-tumor induction butyrate-treated mice. Overall, the present results indicate that in vitro effects of SCFAs did not rely on FFA2 or FFA3 receptor activation, and they were not mirrored in vivo, at least at the tested conditions. Overall, the present results indicate potential in vitro inhibitory effects of SCFAs in breast cancer, independent of FFA2 or FFA3 receptor activation, and, in the metastatic breast cancer model, the butyrate-dosed therapeutic regimen reduced the number of lung metastases.

Redefining bioactive small molecules from microbial metabolites as revolutionary anticancer agents

Cancer treatment remains a significant challenge due to issues such as acquired resistance to conventional therapies and the occurrence of adverse treatment-related toxicities. In recent years, researchers have turned their attention to the microbial world in search of novel and effective drugs to combat this devastating disease. Microbial derived secondary metabolites have proven to be a valuable source of biologically active compounds, which exhibit diverse functions and have demonstrated potential as treatments for various human diseases. The exploration of these compounds has provided valuable insights into their mechanisms of action against cancer cells. In-depth studies have been conducted on clinically established microbial metabolites, unraveling their anticancer properties, and shedding light on their therapeutic potential. This review aims to comprehensively examine the anticancer mechanisms of these established microbial metabolites. Additionally, it highlights the emerging therapies derived from these metabolites, offering a glimpse into the immense potential they hold for anticancer drug discovery. Furthermore, this review delves into approved treatments and major drug candidates currently undergoing clinical trials, focusing on specific molecular targets. It also addresses the challenges and issues encountered in the field of anticancer drug research and development. It also presents a comprehensive exposition of the contemporary panorama concerning microbial metabolites serving as a reservoir for anticancer agents, thereby illuminating their auspicious prospects and the prospect of forthcoming strides in the domain of cancer therapeutics.

Sodium Butyrate Inhibits the Expression of Thymidylate Synthase and Induces Cell Death in Colorectal Cancer Cells

The most commonly used chemotherapy for colorectal cancer (CRC) is the application of 5-fluorouracil (5-FU). Inhibition of thymidylate synthase (TYMS) expression appears to be a promising strategy to overcome the decreased sensitivity to 5-FU caused by high expression of TYMS, which can be induced by 5-FU treatment. Several compounds have been shown to potentially inhibit the expression of TYMS, but it is unclear whether short-chain fatty acids (SCFAs), which are naturally produced by bacteria in the human intestine, can regulate the expression of TYMS. Sodium butyrate (NaB) is the most widely known SCFA for its beneficial effects. Therefore, we investigated the enhancing effects on inhibition of cell viability and induction of apoptosis after co-treatment of NaB with 5-FU in two CRC cell lines, HCT116 and LoVo. This study suggests that the effect of NaB in improving therapeutic sensitivity to 5-FU in CRC cells may result from a mechanism that strongly inhibits the expression of TYMS. This study also shows that NaB inhibits the migration of CRC cells and can cause cell cycle arrest in the G2/M phase. These results suggest that NaB could be developed as a potential therapeutic adjuvant to improve the therapeutic effect of 5-FU in CRC.

Antitumor effect of exopolysaccharide from Lactiplantibacillus plantarum WLPL09 on melanoma mice via regulating immunity and gut microbiota

Exopolysaccharide (EPS-09) from L. plantarum WLPL09 was systemically investigated for the antitumor effect in B16F10 melanoma bearing mice model. The results showed that administraion of EPS-09 (200 mg/kg) could sigificantly inhibit the tumor growth of melanoma bearing mice, with a inhibition rate of 42.53 %. Meanwhile, compared to the Model group, high dose of EPS-09 (200 mg/kg) administraion could increase the spleen index (P = 0.10), promote the splenic lymphocytes proliferation under the stimulation of ConA and LPS with a proliferation rate of 120.58 % and 169.88 %, respectively, enhance the amount of CD4+ and CD8+ T cells (P < 0.0001, P = 0.0149) in tumor tissue, as well as the serum content of cytokines, i.e., TNF-α, IFN-γ, IL-2 (P < 0.05) and IL-6 (P = 0.039) of B16F10 melanoma bearing mice. The transcriptional level analysis revealed that EPS-09 (200 mg/kg) administraion could sigificantly (P < 0.05) upregulate the transcription of apoptosis raleted genes, i.e., P53, Caspase-3 and Caspase-9, and the ratio of Bax/Bcl-2, downregulate the transcription of angiogenesis markers, i.e., Vegf and Fgf2 compared with Model group. Furthermore, administration of EPS-09 could increase the abundance of phylum Firmicutes, family Ruminococcaceae and Lachnospiraceae, and genus Ruminococcus, but reduce the abundance of genus Prevotella, Akkermansia and Oscillospira. Taken together, these results indicate that administration of EPS-09 can induce apoptosis of tumor cell, inhibit tumor angiogenesis, improve the immunity, regulate the intestinal microbiota composition of B16F10 melanoma bearing mice, and play positive roles in the antitumor activity against melanoma.

DPY30 promotes colorectal carcinoma metastasis by upregulating ZEB1 transcriptional expression

DPY30 belongs to the core subunit of components of the histone lysine methyltransferase complex, which is implicated in tumorigenesis, cell senescence, and other biological events. However, its contribution to colorectal carcinoma (CRC) progression and metastasis has yet to be elucidated. Therefore, this study aimed to investigate the biological function of DPY30 in CRC metastasis both in vitro and in vivo. Herein, our results revealed that DPY30 overexpression is significantly positively correlated with positive lymph nodes, epithelial-mesenchymal transition (EMT), and CRC metastasis. Moreover, DPY30 knockdown in HT29 and SW480 cells markedly decreased EMT progression, as well as the migratory and invasive abilities of CRC cells in vitro and lung tumor metastasis in vivo. Mechanistically, DPY30 increased histone H3K4me3 level and promoted EMT and CRC metastasis by upregulating the transcriptional expression of ZEB1. Taken together, our findings indicate that DPY30 may serve as a therapeutic target and prognostic marker for CRC.

Butyrate-mediated Resistance to Trichostatin A Accompanied by Elevated Expression of Glucose Transporter 3 (GLUT3) in Human Colorectal Carcinoma HCT116 Cells

OBJECTIVE

The aim of study was to investigate the correlation of GLUT3 upregulation and butyrate-mediated acquired chemoresistance.

METHOD

A butyrate-resistant CRC cell model was established from parental (PT) HCT116 cells by gradually increasing the concentration of sodium butyrate (NaBu), followed by evaluation of resistance to butyrate and trichostatin A (TSA) by the MTT method. The expression of SLC2A3 gene and GLUT3 protein were assessed by semi-quantitative RT-PCR and western blotting, respectively. The correlation of GLUT3 and butyrate-induced acquired chemoresistance was investigated using SLC2A3 silencing.

RESULTS

Butyrate-resistant (BR) HCT116 cells were more tolerant to butyrate-induced cell death and also resist to 750 and 1000 nM TSA when compared with HCT116-PT cells (p <0.05). Long-term exposure to butyrate revealed that upregulation of the SLC2A3 gene was significantly increased by more than 20 fold (p < 0.01), and that of GLUT3 was elevated by approximately 2 fold (p < 0.05) in HCT116-BR cells. Silencing of the SLC2A3 gene increased the sensitivity of HCT116-BR cells to the effects of TSA.

CONCLUSION

Upregulation of GLUT3 is associated with resistance to butyrate and TSA. GLUT3 is a molecular target for the detection of chemoresistant CRC cells and thus a potential target for diagnostic strategies.

Histone deacetylase inhibitor sodium butyrate regulates the activation of toll-like receptor 4/interferon regulatory factor-3 signaling pathways in prostate cancer cells

CONTEXT

The covalent acetylation and deacetylation of histone proteins by the histone deacetylase (HDAC) enzymes can be considered a novel therapeutic target in prostate cancer (PCa) cells. Sodium butyrate (NaBu) is a HDAC inhibitor (HDACi) which is a promising potential anticancer drug. Toll-like receptor 4 (TLR4) expression is increased in PCa cells and HDACi alter TLR-inducible gene expressions.

AIMS

We aimed to evaluate the effects of NaBu on TLR4 mediating signaling pathways in two different PCa cells (DU-145 and LNCaP) for the first time.

SUBJECTS AND METHODS

The cytotoxic and apoptotic effects of NaBu were determined by the water-soluble tetrazolium salt (WST-1) and Annexin V-AO/PI assays, respectively. Subcellular localization of TLR4, interferon regulatory factor-3 (IRF3) and Nuclear factor kappa B proteins was evaluated by IF assay.

STATISTICAL ANALYSIS USED

All data were statistically analyzed by GraphPad Prism software (V60.1, CA). Obtained data were expressed in a mean ± standard deviation of the three repeated experiments. The differences between control and NaBu treated cells were compared by one-way-ANOVA. P < 0.05 value was considered statistically significant.

RESULTS

Our results showed that NaBu significantly inhibited the viability of PCa cells and increased the percentage of apoptotic cells. However, DU-145 cells were more sensitive to NaBu than LNCaP cells. Furthermore, NaBu can induce the cytoplasmic TLR4 and IRF3 expression in particularly DU-145 cells without affecting nuclear translocation of NF-kB in PCa cells.

CONCLUSIONS

NaBu induces apoptotic cell death and regulated the TLR4/IRF3 signaling pathways in DU-145 cells but not in LNCaP cells. Therefore, PCa cells differentially responded to NaBu treatment due to probably androgen receptor status.

A new strategy for treating colorectal cancer: Regulating the influence of intestinal flora and oncolytic virus on interferon

Colorectal cancer (CRC) has the third highest incidence and the second highest mortality in the world, which seriously affects human health, while current treatments methods for CRC, including systemic therapy, preoperative radiotherapy, and surgical local excision, still have poor survival rates for patients with metastatic disease, making it critical to develop new strategies for treating CRC. In this article, we found that the gut microbiota can modulate the signaling pathways of cancer cells through direct contact with tumor cells, generate inflammatory responses and oxidative stress through interactions between the innate and adaptive immune systems, and produce diverse metabolic combinations to trigger specific immune responses and promote the initiation of systemic type I interferon (IFN-I) and anti-viral immunity. In addition, oncolytic virus-mediated immunotherapy for regulating oncolytic virus can directly lyse tumor cells, induce the immune activity of the body, interact with interferon, inhibit the anti-viral effect of IFN-I, and enhance the anti-tumor effect of IFN-II. Interferon plays an important role in the anti-tumor process. We put forward that exploring the effects of intestinal flora and oncolytic virus on interferon to treat CRC is a promising therapeutic option.

Sodium butyrate enhances titanium nail osseointegration in ovariectomized rats by inhibiting the PKCα/NOX4/ROS/NF-κB pathways

BACKGROUND

Elevated levels of oxidative stress as a consequence of estrogen deficiency serve as a key driver of the onset of osteoporosis (OP). In addition to increasing the risk of bone fractures, OP can reduce the bone volume proximal to titanium nails implanted to treat these osteoporotic fractures, thereby contributing to titanium nail loosening. Sodium butyrate (NaB) is a short-chain fatty acid produced by members of the gut microbiota that exhibits robust antioxidant and anti-inflammatory properties.

METHODS

OP fracture model rats parameters including bone mineral density (BMD), new bone formation, and the number of bonelets around the implanted nail were analyzed via micro-CT scans, H&E staining, and Masson's staining. The protective effects of NaB on such osseointegration and the underlying mechanisms were further studied in vitro using MC3T3-E1 cells treated with carbonyl cyanide m-chlorophenylhydrazone (CCCP) to induce oxidative stress. Techniques including Western immunoblotting, electron microscopy, flow cytometry, alkaline phosphatase (ALP) staining, and osteoblast mineralization assays were employed to probe behaviors such as reactive oxygen species production, mineralization activity, ALP activity, protein expression, and the ability of cells to attach to and survive on titanium plates.

RESULTS

NaB treatment was found to enhance ALP activity, mineralization capacity, and Coll-I, BMP2, and OCN expression levels in CCCP-treated MC3T3-E1 cells, while also suppressing PKC and NF-κB expression and enhancing Nrf2 and HO-1 expression in these cells. NaB further suppressed intracellular ROS production and malondialdehyde levels within the cytosol while enhancing superoxide dismutase activity and lowering the apoptotic death rate. In line with these results, in vivo work revealed an increase in BMD in NaB-treated rats that was associated with enhanced bone formation surrounding titanium nails.

CONCLUSION

These findings indicate that NaB may represent a valuable compound that can be postoperatively administered to aid in treating OP fractures through the enhancement of titanium nail osseointegration.

Clostridium butyricum inhibits epithelial-mesenchymal transition of intestinal carcinogenesis through downregulating METTL3

Colorectal cancer (CRC) is related to gut microbiota dysbiosis, especially butyrate-producing bacteria reduction. Our previous study suggested that administration of Clostridium butyricum, a butyrate-producing bacterium, exerts a crucial effect against CRC, however the potential mechanism is not clear. We first found that methyltransferase-like 3 (METTL3) showed a positive correlation with proliferation, epithelial-mesenchymal transition (EMT), DNA repair, metastasis, and invasion in a database analysis. The expression of METTL3 gradually increased from human normal colon tissue, to adenoma, and carcinoma, and was positively correlated with E-cadherin and CD34 levels. Overexpression of METTL3 promoted the proliferation, migration, and invasion of CRC cells and induced vasculogenic mimicry (VM) formation. Clostridium butyricum could downregulate METTL3 expression in CRC cells and decrease the expression of vimentin and vascular endothelial growth factor receptor 2 to reduce EMT and VM formation. Clostridium butyricum alleviated the pro-oncogenic effect of METTL3 overexpressing plasmid in CRC cells. The anti-EMT effect on METTL3 reduction of C. butyricum could be blunted by knocking down G-protein coupled receptor 43. Moreover, C. butyricum prevented EMT and VM and inhibited tumor metastasis in nude mice. Accordingly, C. butyricum could inhibit EMT and VM formation of intestinal carcinogenesis through downregulating METTL3. These findings broaden our understanding of probiotics supplement in CRC prevention and treatment.

The Importance of Thioredoxin-1 in Health and Disease

Thioredoxin-1 (Trx-1) is a multifunctional protein ubiquitously found in the human body. Trx-1 plays an important role in various cellular functions such as maintenance of redox homeostasis, proliferation, and DNA synthesis, but also modulation of transcription factors and control of cell death. Thus, Trx-1 is one of the most important proteins for proper cell and organ function. Therefore, modulation of Trx gene expression or modulation of Trx activity by various mechanisms, including post-translational modifications or protein-protein interactions, could cause a transition from the physiological state of cells and organs to various pathologies such as cancer, and neurodegenerative and cardiovascular diseases. In this review, we not only discuss the current knowledge of Trx in health and disease, but also highlight its potential function as a biomarker.

Unraveling the function of epithelial-mesenchymal transition (EMT) in colorectal cancer: Metastasis, therapy response, and revisiting molecular pathways

Colorectal cancer (CRC) is a dangerous form of cancer that affects the gastrointestinal tract. It is a major global health concern, and the aggressive behavior of tumor cells makes it difficult to treat, leading to poor survival rates for patients. One major challenge in treating CRC is the metastasis, or spread, of the cancer, which is a major cause of death. In order to improve the prognosis for patients with CRC, it is necessary to focus on ways to inhibit the cancer's ability to invade and spread. Epithelial-mesenchymal transition (EMT) is a process that is linked to the spread of cancer cells, also known as metastasis. The process transforms epithelial cells into mesenchymal ones, increasing their mobility and ability to invade other tissues. This has been shown to be a key mechanism in the progression of colorectal cancer (CRC), a particularly aggressive form of gastrointestinal cancer. The activation of EMT leads to increases in the spread of CRC cells, and during this process, levels of the protein E-cadherin decrease while levels of N-cadherin and vimentin increase. EMT also contributes to the development of resistance to chemotherapy and radiation therapy in CRC. Non-coding RNAs, such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), play a role in regulating EMT in CRC, often through their ability to "sponge" microRNAs. Anti-cancer agents have been shown to suppress EMT and reduce the progression and spread of CRC cells. These findings suggest that targeting EMT or related mechanisms may be a promising approach for treating CRC patients in the clinic.

Short-chain fatty acid-releasing nano-prodrugs for attenuating growth and metastasis of melanoma

Low-molecular-weight (LMW) short-chain fatty acids (SCFAs), such as propionic and butyric acids, have been reported to possess anti-neoplastic effects; however, rapid renal clearance and high dose-based side effects limit their clinical translation. Hence, in this study, we have designed a new self-assembling nano-prodrugs that can effectively supply SCFAs: endogenous enzyme-metabolizable block copolymer poly(ethylene glycol)block-poly(vinyl ester) possessing several units of SCFAs conjugated as side chains via ester linkages. These amphiphilic polymers spontaneously self-assemble into nanostructures under aqueous conditions to form orally administrable nano-prodrugs (butyric acid: Nano^BA and propionic acid: Nano^PA). Herein, we show the therapeutic efficacy of SCFA nanoparticles (Nano^SCFA) in a mouse model of metastasis (melanoma). Ad libitum intake of our Nano^SCFA markedly demonstrated a decrease in the metastatic tumor nodules in the lungs compared with the effect observed after LMW SCFA administration with no discernible toxicity to the GI tract. In contrast, LMW SCFAs, even at a lower concentration than that of the Nano^SCFA, facilitated villus atrophy. Taken together, our work suggests that the use of Nano^SCFA as a therapeutic intervention for metastatic cancer is preferable over typical LMW SCFAs. STATEMENT OF SIGNIFICANCE: Low-molecular-weight (LMW) short-chain fatty acids (SCFAs) have shown versatile therapeutic effects on various diseases, including anti-tumorigenesis effects. However, their clinical translation is limited due to their poor pharmacokinetic profile and adverse effects. To overcome these limitations, we have developed new amphiphilic block copolymer-based SCFA-prodrugs, which self-assemble into nanoparticles in aqueous media (Nano^SCFA). SCFAs are covalently conjugated to the hydrophobic polymer segment via ester linkage, which can be enzymatically metabolized after oral administration. In the present study, we confirmed that ad libitum intake of Nano^SCFAs retarded the growth and metastatic potential of B16-F10 tumors compared to the LMW SCFAs with negligible discernible toxicity, reflecting Nano^SCFA as a preferable therapeutic intervention to LMW SCFA counterparts.

Short-chain fatty acids: possible regulators of insulin secretion

The benefits of gut microbiota-derived short-chain fatty acids (SCFAs) towards health and metabolism have been emerging since the past decade. Extensive studies have been carried out to understand the mechanisms responsible in initiating the functionalities of these SCFAs towards body tissues, which greatly involves the SCFA-specific receptors free fatty acid receptor 2 (FFAR2) and free fatty acid receptor 3 (FFAR3). This review intends to discuss the potential of SCFAs particularly in regulating insulin secretion in pancreatic β-cells, by explaining the production of SCFAs in the gut, the fate of each SCFAs after their production, involvement of FFAR2 and FFAR3 signalling mechanisms and their impacts on insulin secretion. Increased secretion of insulin after SCFAs treatments were reported in many studies, but contradicting evidence also exist in several other studies. Hence, no clear consensus was achieved in determining the true potential of SCFA in regulating insulin secretion. In this review, we explore how such differences were possible and hopefully be able to shed some perspectives in understanding SCFAs-signalling behaviour and preferences.

Short-chain fatty acids reprogram metabolic profiles with the induction of reactive oxygen species production in human colorectal adenocarcinoma cells

Short-chain fatty acids (SCFAs) exhibit anticancer activity in cellular and animal models of colon cancer. Acetate, propionate, and butyrate are the three major SCFAs produced from dietary fiber by gut microbiota fermentation and have beneficial effects on human health. Most previous studies on the antitumor mechanisms of SCFAs have focused on specific metabolites or genes involved in antitumor pathways, such as reactive oxygen species (ROS) biosynthesis. In this study, we performed a systematic and unbiased analysis of the effects of acetate, propionate, and butyrate on ROS levels and metabolic and transcriptomic signatures at physiological concentrations in human colorectal adenocarcinoma cells. We observed significantly elevated levels of ROS in the treated cells. Furthermore, significantly regulated signatures were involved in overlapping pathways at metabolic and transcriptomic levels, including ROS response and metabolism, fatty acid transport and metabolism, glucose response and metabolism, mitochondrial transport and respiratory chain complex, one-carbon metabolism, amino acid transport and metabolism, and glutaminolysis, which are directly or indirectly linked to ROS production. Additionally, metabolic and transcriptomic regulation occurred in a SCFAs types-dependent manner, with an increasing degree from acetate to propionate and then to butyrate. This study provides a comprehensive analysis of how SCFAs induce ROS production and modulate metabolic and transcriptomic levels in colon cancer cells, which is vital for understanding the mechanisms of the effects of SCFAs on antitumor activity in colon cancer.

Potential Role of ROS in Butyrate- and Dietary Fiber-Mediated Growth Inhibition and Modulation of Cell Cycle-, Apoptosis- and Antioxidant-Relevant Proteins in LT97 Colon Adenoma and HT29 Colon Carcinoma Cells

The aim of the present study was to examine whether reactive oxygen species (ROS) contribute to chemopreventive effects of fermentation supernatants (FS) of different dietary fibers (Synergy1^®, oat-, barley-, yeast β-glucan, Curdlan) and butyrate as a fermentation metabolite. LT97 and HT29 cells were treated with butyrate and FS alone or with N-acetyl-cysteine (NAC) and their impact on ROS formation, cell growth, and protein expression (Cyclin D2, p21, PARP, Bid, GPx2) was investigated. Butyrate and FS significantly decreased cell growth. ROS levels were significantly increased, particularly in LT97 cells, while co-treatment with NAC decreased ROS formation and growth inhibitory effects in both cell lines. After treatment with butyrate and FS, Cyclin D2 expression was reduced in LT97 cells and p21 expression was increased in both cell lines. Levels of full-length PARP and Bid were decreased, while levels of cleaved PARP were enhanced. GPx2 expression was significantly reduced by fiber FS in HT29 cells. A notable effect of NAC on butyrate- and FS-modulated protein expression was observed exclusively for PARP and Bid in HT29 cells. From the present results, a contribution of ROS to growth inhibitory and apoptotic effects of butyrate and FS on LT97 and HT29 cells cannot be excluded.

Breast milk jaundice affects breastfeeding: From the perspective of intestinal flora and SCFAs-GPR41/43

Breast milk jaundice (BMJ) is one of the main factors leading to interruption or early termination of breastfeeding. Interrupting breastfeeding to treat BMJ may increase the adverse consequences for infant growth and disease prevention. The Intestinal flora and metabolites are increasingly recognized as a potential therapeutic target in BMJ. First, dysbacteriosis can lead to a decrease in the metabolite short-chain fatty acids. At the same time, SCFA can act on specific G protein-coupled receptors 41 and 43 (GPR41/43), and a decrease in SCFA downregulates the GPR41/43 pathway, leading to a diminished inhibition of intestinal inflammation. In addition, intestinal inflammation leads to a decrease in intestinal motility and a large amount of bilirubin enters the enterohepatic circulation. Ultimately, these changes will result in the development of BMJ. In this review, we will describe the underlying pathogenetic mechanism of the intestinal flora effects on BMJ.

Gut microbiota-derived short-chain fatty acids regulate gastrointestinal tumor immunity: a novel therapeutic strategy?

Tumor immune microenvironment (TIME), a tumor-derived immune component, is proven to be closely related to the development, metastasis, and recurrence of tumors. Gut microbiota and its fermented-metabolites short-chain fatty acids (SCFAs) play a critical role in maintaining the immune homeostasis of gastrointestinal tumors. Consisting mainly of acetate, propionate, and butyrate, SCFAs can interact with G protein-coupled receptors 43 of T helper 1 cell or restrain histone deacetylases (HDACs) of cytotoxic T lymphocytes to exert immunotherapy effects. Studies have shed light on SCFAs can mediate the differentiation and function of regulatory T cells, as well as cytokine production in TIME. Additionally, SCFAs can alter epigenetic modification of CD8⁺ T cells by inhibiting HDACs to participate in the immune response process. In gastrointestinal tumors, the abundance of SCFAs and their producing bacteria is significantly reduced. Direct supplementation of dietary fiber and probiotics, or fecal microbiota transplantation to change the structure of gut microbiota can both increase the level of SCFAs and inhibit tumor development. The mechanism by which SCFAs modulate the progression of gastrointestinal tumors has been elucidated in this review, aiming to provide prospects for the development of novel immunotherapeutic strategies.

Sodium butyrate in both prevention and supportive treatment of colorectal cancer

Accumulating evidence suggests that selected microbiota-derived metabolites play a significant role in both tumor prevention and supportive treatment of cancer. Short-chain fatty acids (SCFAs), i.e., mainly acetate, proprionate, and butyrate, are one of them. Nowadays, it is known that butyrate is a key microbial metabolite. Therefore, in the current review, we focused on butyrate and sodium butyrate (NaB) in the context of colorectal cancer. Notably, butyrate is characterized by a wide range of beneficial properties/activities. Among others, it influences the function of the immune system, maintains intestinal barrier integrity, positively affects the efficiency of anti-cancer treatment, and may reduce the risk of mucositis induced by chemotherapy. Taking into consideration these facts, we analyzed NaB (which is a salt of butyric acid) and its impact on gut microbiota as well as anti-tumor activity by describing molecular mechanisms. Overall, NaB is available as, for instance, food with special medical purposes (depending on the country's regulation), and its administration seems to be a promising option for colorectal cancer patients.

Synergistic effects of sodium butyrate and cisplatin against cervical carcinoma in vitro and in vivo

BACKGROUNDS

Cisplatin-based chemotherapy has been considered as the pivotal option for treating cervical cancer. However, some patients may present a poor prognosis due to resistance to chemotherapy. As a metabolite of natural products, sodium butyrate (NaB) could inhibit the proliferation of several malignant cells, but little is known about its combination with cisplatin in the treatment of cervical cancer.

MATERIALS AND METHODS

Flow cytometry, CCK-8 assay, and Transwell assay were utilized to analyze the cellular apoptosis, viability, cellular migration and invasion upon treating with NaB and/or cisplatin. The allograft mice model was established, followed by evaluating the tumor volume and necrotic area in mice treated with NaB and/or cisplatin. Western blot was performed for detecting protein expression involved in epithelial-mesenchymal transition (EMT) and the expression of MMPs. Immunohistochemical staining was conducted with the tumor sections. The transcription, expression, and cellular translocation of β-catenin were determined using luciferase reporter gene assay, Real-Time PCR, Western blot, and confocal laser scanning microscope, respectively.

RESULTS

NaB combined with cisplatin inhibited cell viability by promoting apoptosis of cervical cancer cells. In vivo experiments indicated that NaB combined with cisplatin could inhibit tumor growth and induce cancer cell necrosis. Single application of NaB activated the Wnt signaling pathway and induced partial EMT. NaB alone up-regulated MMP2, MMP7 and MMP9 expression, and promoted the migration and invasion of cervical cancer cells. The combination of cisplatin and NaB inhibited cellular migration and invasion by abrogating the nuclear transition of β-catenin, reverse EMT and down-regulate MMP2, MMP7 and MMP9. Immunohistochemical staining indicated that NaB combined with cisplatin up-regulated the expression of E-cadherin and reverse the EMT phenotype in the mice model.

CONCLUSIONS

NaB serves as a sensitizer for cisplatin, which may be a promising treatment regimen for cervical cancer when combined both. NaB alone should be utilized with caution for treating cervical cancer as it may promote the invasion and migration of cervical cancer cells.

Interaction between microbiota and immunity and its implication in colorectal cancer

Colorectal cancer (CRC) is one of the leading causes of cancer-related death in the world. Besides genetic causes, colonic inflammation is one of the major risk factors for CRC development, which is synergistically regulated by multiple components, including innate and adaptive immune cells, cytokine signaling, and microbiota. The complex interaction between CRC and the gut microbiome has emerged as an important area of current CRC research. Metagenomic profiling has identified a number of prominent CRC-associated bacteria that are enriched in CRC patients, linking the microbiota composition to colitis and cancer development. Some microbiota species have been reported to promote colitis and CRC development in preclinical models, while a few others are identified as immune modulators to induce potent protective immunity against colitis and CRC. Mechanistically, microbiota regulates the activation of different immune cell populations, inflammation, and CRC via crosstalk between innate and adaptive immune signaling pathways, including nuclear factor kappa B (NF-κB), type I interferon, and inflammasome. In this review, we provide an overview of the potential interactions between gut microbiota and host immunity and how their crosstalk could synergistically regulate inflammation and CRC, thus highlighting the potential roles and mechanisms of gut microbiota in the development of microbiota-based therapies to prevent or alleviate colitis and CRC.

Ras Participates in the Regulation of the Stability of Adenoviral Protein E1A via MAP-kinase ERK

The E1A adenoviral protein required for the initiation of the viral life cycle is being actively studied as a sensitizing agent in the combination therapy of cancer, and tumors with activated Ras in particular. We investigated the role played by the Ras signaling pathway in the regulation of E1A protein stability and showed that overexpression of activated Ras increases the basal level of E1A, but enhances the degradation of the E1A protein under treatment with histone deacetylase inhibitors (HDIs). It has been found that the MAP kinase ERK is the key factor in E1A stabilization, and ERK inactivation upon HDI treatment reduces the E1A protein level. Our results indicate that the combination treatment of tumors with activated Ras using adenoviral E1A and HDI has limitations attributed to intense HDI-dependent degradation of E1A. Nevertheless, the established contribution of ERK kinase to the regulation of E1A stability can be used to search for new effective drug combinations based on the adenoviral E1A protein.

Prediction of the Mechanism of Sodium Butyrate against Radiation-Induced Lung Injury in Non-Small Cell Lung Cancer Based on Network Pharmacology and Molecular Dynamic Simulations and Molecular Dynamic Simulations

Background

Radiation-induced lung injury (RILI) is a severe side effect of radiotherapy for non-small cell lung cancer (NSCLC) ,and one of the major hindrances to improve the efficacy of radiotherapy. Previous studies have confirmed that sodium butyrate (NaB) has potential of anti-radiation toxicity. However, the mechanism of the protective effect of NaB against RILI has not yet been clarified. This study aimed to explore the underlying protective mechanisms of NaB against RILI in NSCLC through network pharmacology, molecular docking, molecular dynamic simulations and in vivo experiments.

Methods

The predictive target genes of NaB were obtained from the PharmMapper database and the literature review. The involved genes of RILI and NSCLC were predicted using OMIM and GeneCards database. The intersectional genes of drug and disease were identified using the Venny tool and uploaded to the Cytoscape software to identify 5 core target genes of NaB associated with RILI. The correlations between the 5 core target genes and EGFR, PD-L1, immune infiltrates, chemokines and chemokine receptors were analyzed using TIMER 2.0, TIMER and TISIDB databases. We constructed the mechanism maps of the 3 key signaling pathways using the KEGG database based on the results of GO and KEGG analyses from Metascape database. The 5 core target genes and drug were docked using the AutoDock Vina tool and visualized using PyMOL software. GROMACS software was used to perform 100 ns molecular dynamics simulation. Irradiation-induced lung injury model in mice were established to assess the therapeutic effects of NaB.

Results

A total of 51 intersectional genes involved in NaB against RILI in NSCLC were identified. The 5 core target genes were AKT1, TP53, NOTCH1, SIRT1, and PTEN. The expressions of the 5 core target genes were significantly associated with EGFR, PD-L1, immune infiltrates, chemokines and chemokine receptors, respectively. The results from GO analysis of the 51 intersectional genes revealed that the biological processes were focused on the regulation of smooth muscle cell proliferation, oxidative stress and cell death, while the three key KEGG pathways were enriched in PI3K-Akt signal pathway, p53 signal pathway, and FOXO signal pathway. The docking of NaB with the 5 core target genes showed affinity and stability, especially AKT1. In vivo experiments showed that NaB treatment significantly protected mice from RILI, with reduced lung histological damage. In addition, NaB treatment significantly inhibited the PI3K/Akt signaling pathway.

Conclusions

NaB may protect patients from RILI in NSCLC through multiple target genes including AKT1, TP53, NOTCH1, SIRT1 and PTEN, with multiple signaling pathways involving, including PI3K-Akt pathway, p53 pathway, and FOXO pathways. Our findings effectively provide a feasible theoretical basis to further elucidate the mechanism of NaB in the treatment of RILI.

Butyrate Drives Metabolic Rewiring and Epigenetic Reprogramming in Human Colon Cancer Cells

SCOPE

Butyrate (B) is a short-chain fatty acid produced by dietary fiber, known to inhibit histone deacetylases (HDACs) and possess cancer-preventive/anticancer effects. However, the role of B in metabolic rewiring, epigenomic reprogramming, transcriptomic network, NRF2 signaling, and eliciting cancer-preventive effects in colorectal cancer (CRC) HCT116 cell remains unclear.

METHODS AND RESULTS

Sodium butyrate (NaB) dose-dependently inhibits the growth of CRC HCT116 cells. NaB inhibits NRF2/NRF2-target genes and blocks NRF2-ARE signaling. NaB increases NRF2 negative regulator KEAP1 expression through inhibiting its promoter methylation. Associative analysis of DEGs (differentially expressed genes) from RNA-seq and DMRs (differentially methylated regions) from CpG methyl-seq identified the tumor suppressor gene ABCA1 and tumor promote gene EGR3 are correlated with their promoters' CpG methylation indicating NaB regulates cancer markers through modulating their promoter methylation. NaB activated the mitochondrial tricarboxylic acid (TCA) cycle while inhibited the methionine metabolism which are both tightly coupled to the epigenetic machinery. NaB regulates the epigenetic enzymes/genes including DNMT1, HAT1, KDM1A, KDM1B, and TET1. Altogether, B's regulation of metabolites coupled to the epigenetic enzymes illustrates the potential underlying biological connectivity between metabolomics and epigenomics.

CONCLUSION

B regulates KEAP1/NRF2 signaling, drives metabolic rewiring, CpG methylomic, and transcriptomic reprogramming contributing to the overall cancer-prevention/anticancer effect in the CRC cell model.

Regulation of epithelial-mesenchymal transition by protein lysine acetylation

The epithelial-mesenchymal transition (EMT) is a vital driver of tumor progression. It is a well-known and complex trans-differentiation process in which epithelial cells undergo morphogenetic changes with loss of apical-basal polarity, but acquire spindle-shaped mesenchymal phenotypes. Lysine acetylation is a type of protein modification that favors reversibly altering the structure and function of target molecules via the modulation of lysine acetyltransferases (KATs), as well as lysine deacetylases (KDACs). To date, research has found that histones and non-histone proteins can be acetylated to facilitate EMT. Interestingly, histone acetylation is a type of epigenetic regulation that is capable of modulating the acetylation levels of distinct histones at the promoters of EMT-related markers, EMT-inducing transcription factors (EMT-TFs), and EMT-related long non-coding RNAs to control EMT. However, non-histone acetylation is a post-translational modification, and its effect on EMT mainly relies on modulating the acetylation of EMT marker proteins, EMT-TFs, and EMT-related signal transduction molecules. In addition, several inhibitors against KATs and KDACs have been developed, some of which can suppress the development of different cancers by targeting EMT. In this review, we discuss the complex biological roles and molecular mechanisms underlying histone acetylation and non-histone protein acetylation in the control of EMT, highlighting lysine acetylation as potential strategy for the treatment of cancer through the regulation of EMT.

Organoid technologies for the study of intestinal microbiota–host interactions

Postbiotics have recently emerged as critical effectors of the activity of probiotics and, because of their safety profile, they are considered potential therapeutics for the treatment of fragile patients. Here, we present recent studies on probiotics and postbiotics in the context of novel discovery tools, such as organoids and organoid-based platforms, and nontransformed preclinical models, that can be generated from intestinal stem cells. The implementation of organoid-related techniques is the next gold standard for unraveling the effect of microbial communities on homeostasis, inflammation, idiopathic diseases, and cancer in the gut. We also summarize recent studies on biotics in organoid-based models and offer our perspective on future directions.

Short-Chain Fatty Acid Butyrate Induces Cilia Formation and Potentiates the Effects of HDAC6 Inhibitors in Cholangiocarcinoma Cells

Cholangiocarcinoma (CCA) is a deadly form of liver cancer with limited therapeutic approaches. The pathogenesis of CCA involves the loss of primary cilia in cholangiocytes, an important organelle that regulates several key cellular functions including the regulation of cell polarity, growth, and differentiation, by a mechanism involving increased expression of deacetylases like HDAC6 and SIRT1. Therefore, cilia restoration may represent an alternative and novel therapeutic approach against CCA. Butyrate is produced by bacterial fermentation of fibers in the intestine and has been shown to inhibit SIRT1, showing antitumor effects on various cancers. Herein, we investigated the role of butyrate on CCA cell proliferation, migration, and EMT and evaluated the synergistic effects with specific HDAC6 inhibition. When CCA cells, including HuCCT1 and KMCH, were treated with butyrate, the cilia formation and acetylated-tubulin levels were increased, while no significant effects were observed in normal human cholangiocytes. Butyrate treatment also depicted reduced cell proliferation in HuCCT1 and KMCH cells, but on the other hand, it affected cell growth of the normal cholangiocytes only at high concentrations. In HuCCT1 cells, spheroid formation and cell migration were also halted by butyrate treatment. Furthermore, we found that butyrate augmented the previously described effects of HDAC6 inhibitors on CCA cell proliferation and migration by reducing the expression of CD44, cyclin D1, PCNA, Zeb1, and Vimentin. In summary, butyrate targets cancer cell growth and migration and enhances the anti-cancer effects of HDAC6 inhibitors in CCA cells, suggesting that butyrate may have therapeutic effects in CCA and other ciliopathies.

Evaluation of FOXCUT, CCAT2, and HULC LncRNA Expression Levels and Apoptosis Induction by Sodium Butyrate in PC-3 and LNCAP Prostate Cancer Cell Lines

Sodium butyrate (NaBu) is a short-chain fatty acid acting as a histone deacetylase inhibitor, and has been shown to be a potential regulator of cancer cell death. This study aimed to evaluate the effect of NaBu on cell cycle control, apoptosis, and expression of some lncRNAs in two human prostate cancer cells (PC-3 and LNCAP). Cell viability was assessed and the appropriate dose was determined using the MTT assay. Real-time PCR technique was also used to evaluate the expression levels of HULC, FOXCUT, and CCAT2 lncRNAs. Apoptosis was diagnosed using annexin V staining, and cell cycle distribution was then assessed using flow cytometry with propidium iodide DNA staining. NaBu induced apoptosis in both prostate cancer cell lines in a dose-dependent manner. The expressions of CCAT2 and HULC lncRNAs genes have significantly decreased in the presence of NaBu (P <0.05) in both PC3 and LNCAP cell lines, in comparison with the control. However, no significant difference was observed in the expression of FOXCUT lncRNAs. Moreover, the results of flow cytometry showed an increase in cell cycle arrest of LNCAP cell line at the sub-G1 stage as compared to the control cells, but no significant difference was observed between the control cells and NaBu-exposed PC-3 cells. In addition, the percentages of early and late apoptotic cells following treatment with NaBu were 80% and 49.63% in LNCAP and PC-3 cells, respectively. Our results suggest that NaBu has a positive effect on the induction of apoptosis and inhibition of cell cycle in PC-3 and LNCAP prostate cancer cells.

Toward Tumor Fight and Tumor Microenvironment Remodeling: PBA Induces Cell Cycle Arrest and Reduces Tumor Hybrid Cells' Pluripotency in Bladder Cancer

Bladder cancer (BC) is the second most frequent cancer of the genitourinary system. The most successful therapy since the 1970s has consisted of intravesical instillations of Bacillus Calmette-Guérin (BCG) in which the tumor microenvironment (TME), including macrophages, plays an important role. However, some patients cannot be treated with this therapy due to comorbidities and severe inflammatory side effects. The overexpression of histone deacetylases (HDACs) in BC has been correlated with macrophage polarization together with higher tumor grades and poor prognosis. Herein we demonstrated that phenylbutyrate acid (PBA), a HDAC inhibitor, acts as an antitumoral compound and immunomodulator. In BC cell lines, PBA induced significant cell cycle arrest in G1, reduced stemness markers and increased PD-L1 expression with a corresponding reduction in histone 3 and 4 acetylation patterns. Concerning its role as an immunomodulator, we found that PBA reduced macrophage IL-6 and IL-10 production as well as CD14 downregulation and the upregulation of both PD-L1 and IL-1β. Along this line, PBA showed a reduction in IL-4-induced M2 polarization in human macrophages. In co-cultures of BC cell lines with human macrophages, a double-positive myeloid-tumoral hybrid population (CD11b+EPCAM+) was detected after 48 h, which indicates BC cell-macrophage fusions known as tumor hybrid cells (THC). These THC were characterized by high PD-L1 and stemness markers (SOX2, NANOG, miR-302) as compared with non-fused (CD11b-EPCAM+) cancer cells. Eventually, PBA reduced stemness markers along with BMP4 and IL-10. Our data indicate that PBA could have beneficial properties for BC management, affecting not only tumor cells but also the TME.

Sodium Butyrate Enhances Curcuminoids Permeability through the Blood-Brain Barrier, Restores Wnt/β-Catenin Pathway Antagonists Gene Expression and Reduces the Viability of Glioblastoma Cells

Glioblastoma (GBM) is an extremely aggressive brain tumor awaiting novel, efficient, and minimally toxic treatment. Curcuminoids (CCM), polyphenols from Curcuma longa, and sodium butyrate (NaBu), a histone deacetylase inhibitor naturally occurring in the human body, await elucidation as potential anti-GBM agents. Thus, the aim of this study was to analyze CCM and NaBu both separately and as a combination treatment using three GBM cell lines. MTT was used for cytotoxicity evaluation, and the combination index was calculated for synergism prediction. Cell cycle, apoptosis, and reactive oxygen species (ROS) generation were analyzed using flow cytometry. DNA methylation was verified by MS-HRM and mRNA expression by qPCR. The permeability through the blood-brain barrier (BBB) and through the nasal cavity was evaluated using PAMPA model. The results of this study indicate that CCM and NaBu synergistically reduce the viability of GBM cells inducing apoptosis and cell cycle arrest. These effects are mediated via ROS generation and changes in gene expression, including upregulation of Wnt/β-catenin pathway antagonists, SFRP1, and RUNX3, and downregulation of UHRF1, the key epigenetic regulator. Moreover, NaBu ameliorated CCM permeability through the BBB and the nasal cavity. We conclude that CCM and NaBu are promising agents with anti-GBM properties.

Albuca Bracteate Polysaccharides Synergistically Enhance the Anti-Tumor Efficacy of 5-Fluorouracil Against Colorectal Cancer by Modulating β-Catenin Signaling and Intestinal Flora

The first-line treatment for colorectal cancer (CRC) is 5-fluorouracil (5-FU). However, the efficacy of this treatment is sometimes limited owing to chemoresistance as well as treatment-associated intestinal mucositis and other adverse events. Growing evidence suggests that certain phytochemicals have therapeutic and cancer-preventing properties. Further, the synergistic interactions between many such plant-derived products and chemotherapeutic drugs have been linked to improved therapeutic efficacy. Polysaccharides extracted from Albuca bracteata (Thunb.) J.C.Manning and Goldblatt (ABP) have been reported to exhibit anti-oxidant, anti-inflammatory, and anti-tumor properties. In this study, murine CRC cells (CT26) and a murine model of CRC were used to examine the anti-tumor properties of ABP and explore the mechanism underlying the synergistic interactions between ABP and 5-FU. Our results revealed that ABP could inhibit tumor cell proliferation, invasion, and migratory activity in vitro and inhibited tumor progression in vivo by suppressing β-catenin signaling. Additionally, treatment with a combination of ABP and 5-FU resulted in better outcomes than treatment with either agent alone. Moreover, this combination therapy resulted in the specific enrichment of Ruminococcus, Anaerostipes, and Oscillospira in the intestinal microbiota and increased fecal short-chain fatty acid (SCFA) levels (acetic acid, propionic acid, and butyric acid). The improvement in the intestinal microbiota and the increase in beneficial SCFAs contributed to enhanced therapeutic outcomes and reduced the adverse effects of 5-FU. Together, these data suggest that ABP exhibits anti-neoplastic activity and can effectively enhance the efficacy of 5-FU in CRC treatment. Therefore, further research on the application of ABP in the development of novel anti-tumor drugs and adjuvant compounds is warranted and could improve the outcomes of CRC patients.

Combining Sodium Butyrate With Cisplatin Increases the Apoptosis of Gastric Cancer In Vivo and In Vitro via the Mitochondrial Apoptosis Pathway

Introduction: The gastrointestinal malignancy, gastric cancer (GC), has a high incidence worldwide. Cisplatin is a traditional chemotherapeutic drug that is generally applied to treat cancer; however, drug tolerance affects its efficacy. Sodium butyrate is an intestinal flora derivative that has general anti-cancer effects in vitro and in vivo via pro-apoptosis effects and can improve prognosis in combination with traditional chemotherapy drugs. The present study aimed to assess the effect of sodium butyrate combined with cisplatin on GC. Methods: A Cell Counting Kit-8 assay was used to assess the viability of GC cells in vitro. Hoechst 33,258 staining and Annexin V-Phycoerythrin/7-Aminoactinomycin D were used to qualitatively and quantitatively detect apoptosis in GC cells. Intracellular reactive oxygen species (ROS) measurement and a mitochondrial membrane potential (MMP) assay kit were used to qualitatively and quantitatively reflect the function of mitochondria in GC cells. Western blotting was used to verify the above experimental results. A nude mouse xenograft tumor model was used to evaluate the anti-tumor efficacity of sodium and cisplatin butyrate in vivo. Results: Cisplatin combined with sodium butyrate increased the apoptosis of GC cells. In the nude mouse xenograft tumor model, sodium butyrate in combination with cisplatin markedly inhibited the growth of the tumor more effectively than either single agent. The combination of sodium butyrate and cisplatin increased the intracellular ROS, decreased the MMP, and suppressed the invasion and migration abilities of GC cells. Western blotting verified that the combination of sodium butyrate and cisplatin remarkably enhanced the levels of mitochondrial apoptosis-related pathway proteins. Conclusion: Sodium butyrate, a histone acetylation inhibitor produced by intestinal flora fermentation, combined with cisplatin enhanced the apoptosis of GC cells through the mitochondrial apoptosis-related pathway, which might be considered as a therapeutic option for GC.

The Bladder Microbiome Is Associated with Epithelial-Mesenchymal Transition in Muscle Invasive Urothelial Bladder Carcinoma

Simple Summary

The abundance of microbial species residing within tumors is correlated to cancer progression across many different cancers, including bladder cancer. However, links between the intratumor microbiome of muscle invasive bladder cancer (MIBC) and specific mechanisms of cancer progression have not been well studied. In this paper, we aim to uncover the relationship between microbial abundance in the MIBC intratumor microbiome and epithelial–mesenchymal transition (EMT), one key feature of cancer progression. By comparing the gene expression of EMT-associated genes to the abundance of intratumor microbes in MIBC patients, we found significant correlations between the abundance of microbes and either the upregulation or downregulation of EMT-associated genes. Our findings call for an investigation of possible mechanisms through which the microbiome may regulate EMT in MIBC patients. With further investigation, our findings can be used to provide a new, microbial approach in the diagnosis and therapy of MIBC.

Abstract

The intra-tumor microbiome has recently been linked to epithelial–mesenchymal transition (EMT) in a number of cancers. However, the relationship between EMT and microbes in bladder cancer has not been explored. In this study, we profiled the abundance of individual microbe species in the tumor samples of over 400 muscle invasive bladder carcinoma (MIBC) patients. We then correlated microbe abundance to the expression of EMT-associated genes and genes in the extracellular matrix (ECM), which are key players in EMT. We discovered that a variety of microbes, including E. coli, butyrate-producing bacterium SM4/1, and a species of Oscillatoria, were associated with expression of classical EMT-associated genes, including E-cadherin, vimentin, SNAI2, SNAI3, and TWIST1. We also found significant correlations between microbial abundance and the expression of genes in the ECM, specifically collagens and elastin. Lastly, we found that a large number of microbes exhibiting significant correlations to EMT are also associated with clinical prognosis and outcomes. We further determined that the microbes we profiled were likely not environmental contaminants. In conclusion, we discovered that the intra-tumoral microbiome could potentially play a significant role in the regulation of EMT in MIBC.

Immune System, Microbiota, and Microbial Metabolites: The Unresolved Triad in Colorectal Cancer Microenvironment

Colorectal cancer (CRC) is one of the most common cancers worldwide. As with other cancers, CRC is a multifactorial disease due to the combined effect of genetic and environmental factors. Most cases are sporadic, but a small proportion is hereditary, estimated at around 5-10%. In both, the tumor interacts with heterogeneous cell populations, such as endothelial, stromal, and immune cells, secreting different signals (cytokines, chemokines or growth factors) to generate a favorable tumor microenvironment for cancer cell invasion and metastasis. There is ample evidence that inflammatory processes have a role in carcinogenesis and tumor progression in CCR. Different profiles of cell activation of the tumor microenvironment can promote pro or anti-tumor pathways; hence they are studied as a key target for the control of cancer progression. Additionally, the intestinal mucosa is in close contact with a microorganism community, including bacteria, bacteriophages, viruses, archaea, and fungi composing the gut microbiota. Aberrant composition of this microbiota, together with alteration in the diet-derived microbial metabolites content (such as butyrate and polyamines) and environmental compounds has been related to CRC. Some bacteria, such as pks+ Escherichia coli or Fusobacterium nucleatum, are involved in colorectal carcinogenesis through different pathomechanisms including the induction of genetic mutations in epithelial cells and modulation of tumor microenvironment. Epithelial and immune cells from intestinal mucosa have Pattern-recognition receptors and G-protein coupled receptors (receptor of butyrate), suggesting that their activation can be regulated by intestinal microbiota and metabolites. In this review, we discuss how dynamics in the gut microbiota, their metabolites, and tumor microenvironment interplays in sporadic and hereditary CRC, modulating tumor progression.

Tackling tumor microenvironment through epigenetic tools to improve cancer immunotherapy

BACKGROUND

Epigenetic alterations are known contributors to cancer development and aggressiveness. Additional to alterations in cancer cells, aberrant epigenetic marks are present in cells of the tumor microenvironment, including lymphocytes and tumor-associated macrophages, which are often overlooked but known to be a contributing factor to a favorable environment for tumor growth. Therefore, the main aim of this review is to give an overview of the epigenetic alterations affecting immune cells in the tumor microenvironment to provoke an immunosuppressive function and contribute to cancer development. Moreover, immunotherapy is briefly discussed in the context of epigenetics, describing both its combination with epigenetic drugs and the need for epigenetic biomarkers to predict response to immune checkpoint blockage.

MAIN BODY

Combining both topics, epigenetic machinery plays a central role in generating an immunosuppressive environment for cancer growth, which creates a barrier for immunotherapy to be successful. Furthermore, epigenetic-directed compounds may not only affect cancer cells but also immune cells in the tumor microenvironment, which could be beneficial for the clinical response to immunotherapy.

CONCLUSION

Thus, modulating epigenetics in combination with immunotherapy might be a promising therapeutic option to improve the success of this therapy. Further studies are necessary to (1) understand in depth the impact of the epigenetic machinery in the tumor microenvironment; (2) how the epigenetic machinery can be modulated according to tumor type to increase response to immunotherapy and (3) find reliable biomarkers for a better selection of patients eligible to immunotherapy.

Postbiotics, Metabolic Signaling, and Cancer

Postbiotics are health-promoting microbial metabolites delivered as a functional food or a food supplement. They either directly influence signaling pathways of the body or indirectly manipulate metabolism and the composition of intestinal microflora. Cancer is the second leading cause of death worldwide and even though the prognosis of patients is improving, it is still poor in the substantial part of the cases. The preventable nature of cancer and the importance of a complex multi-level approach in anticancer therapy motivate the search for novel avenues of establishing the anticancer environment in the human body. This review summarizes the principal findings demonstrating the usefulness of both natural and synthetic sources of postbotics in the prevention and therapy of cancer. Specifically, the effects of crude cell-free supernatants, the short-chain fatty acid butyrate, lactic acid, hydrogen sulfide, and β-glucans are described. Contradictory roles of postbiotics in healthy and tumor tissues are highlighted. In conclusion, the application of postbiotics is an efficient complementary strategy to combat cancer.

Colon cancer cell differentiation by sodium butyrate modulates metabolic plasticity of Caco-2 cells via alteration of phosphotransfer network

The ability of butyrate to promote differentiation of cancer cells has important implication for colorectal cancer (CRC) prevention and therapy. In this study, we examined the effect of sodium butyrate (NaBT) on the energy metabolism of colon adenocarcinoma Caco-2 cells coupled with their differentiation. NaBT increased the activity of alkaline phosphatase indicating differentiation of Caco-2 cells. Changes in the expression of pluripotency-associated markers OCT4, NANOG and SOX2 were characterized during the induced differentiation at mRNA level along with the measures that allowed distinguishing the expression of different transcript variants. The functional activity of mitochondria was studied by high-resolution respirometry. Glycolytic pathway and phosphotransfer network were analyzed using enzymatical assays. The treatment of Caco-2 cells with NaBT increased production of ATP by oxidative phosphorylation, enhanced mitochondrial spare respiratory capacity and caused rearrangement of the cellular phosphotransfer networks. The flexibility of phosphotransfer networks depended on the availability of glutamine, but not glucose in the cell growth medium. These changes were accompanied by suppressed cell proliferation and altered gene expression of the main pluripotency-associated transcription factors. This study supports the view that modulating cell metabolism through NaBT can be an effective strategy for treating CRC. Our data indicate a close relationship between the phosphotransfer performance and metabolic plasticity of CRC, which is associated with the cell differentiation state.

Gut Microbiota-Derived Metabolites in the Development of Diseases

Gut microbiota is increasingly recognized as a metabolic organ essential for human health. Compelling evidences show a variety set of links between diets and gut microbial homeostasis. Changes in gut microbial flora would probably contribute to the development of certain diseases such as diabetes, heart disease, allergy, and psychiatric diseases. In addition to the composition of gut microbiota, the metabolites derived from gut microbiota have emerged as a pivotal regulator in diseases development. Since high-fat and high-protein diets substantially affect the gut microbial ecology and human health, the current review summarizes the gut microbiota-derived metabolites such as short-chain fatty acids (SCFAs), amino acids, and their derivatives and highlights the mechanisms underlying the host responses to these bioactive substances.