Effect of Food Additive Citric Acid on The Growth of Human Esophageal Carcinoma Cell Line EC109

Influence of Acidic pH on Wound Healing In Vivo: A Novel Perspective for Wound Treatment

There has been little understanding of acidification functionality in wound healing, highlighting the need to study the efficacy of wound acidification on wound closure and cellular activity in non-infected wounds. This study is focused on establishing the healing potential of wound acidification in non-infected wounds. Acidic buffers, constituting either phosphoric or citric acid, were employed to modify the physiological pH of non-infected full-thickness excisional murine wounds. Acidification of the wound by acidic buffers was found to be an effective strategy to improve wound healing. A significant improvement in wound healing parameters was observed as early as 2 days post-treatment with acidic buffers compared to controls, with faster rate of epithelialization, wound closure and higher levels of collagen at day 7. pH is shown to play a role in mediating the rate of wound healing, with acidic buffers formulated at pH 4 observed to stimulate faster recovery of wounded tissues than pH 6 buffers. Our study shows the importance of maintaining an acidic wound microenvironment at pH 4, which could be a potential therapeutic strategy for wound management.

Combined nature and human selections reshaped peach fruit metabolome

Background

Plant metabolites reshaped by nature and human beings are crucial for both their lives and human health. However, which metabolites respond most strongly to selection pressure at different evolutionary stages and what roles they undertake on perennial fruit crops such as peach remain unclear.

Results

Here, we report 18,052 significant locus-trait associations, 12,691 expression-metabolite correlations, and 294,676 expression quantitative trait loci (eQTLs) for peach. Our results indicate that amino acids accumulated in landraces may be involved in the environmental adaptation of peaches by responding to low temperature and drought. Moreover, the contents of flavonoids, the major nutrients in fruits, have kept decreasing accompanied by the reduced bitter flavor during both domestication and improvement stages. However, citric acid, under the selection of breeders’ and consumers’ preference for flavor, shows significantly different levels between eastern and western varieties. This correlates with differences in activity against cancer cells in vitro in fruit from these two regions. Based on the identified key genes regulating flavonoid and acid contents, we propose that more precise and targeted breeding technologies should be designed to improve peach varieties with rich functional contents because of the linkage of genes related to bitterness and acid taste, antioxidant and potential anti-cancer activity that are all located at the top of chromosome 5.

Conclusions

This study provides powerful data for future improvement of peach flavor, nutrition, and resistance in future and expands our understanding of the effects of natural and artificial selection on metabolites.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13059-022-02719-6.

In Vitro Wound Healing Properties of Novel Acidic Treatment Regimen in Enhancing Metabolic Activity and Migration of Skin Cells

Strategies that alter the pH of wounds to improve healing outcomes are an emerging area of interest. Currently, there is limited understanding of the effect of hydrogen (H⁺) on the functionality of skin cells during proliferation and migration, highlighting the need for research to determine the effect of pH during wound healing. This study aimed to determine the effect of acidification on the metabolic activity and migration of human immortalized keratinocytes (HaCaT) and human foreskin fibroblasts (HFF). In vitro models were used with phosphoric and citric acid buffers at a pH range between 3 and 7. Our results showed that cells were more viable in buffers with low rather than high ionic strength. A time-dependent effect of the acidification treatment was also observed with cell metabolic activity varying with treatment duration and frequency. Our results showed that a 24 h treatment and subsequent resting phase significantly improved cell proliferation and migration. This in vitro study is the first to establish a correlation between the role of acidic pH, molarity and treatment regimen in cellular activity. Our data demonstrated a positive effect of acidic pH on cell metabolic activity and migration rate, suggesting a clinical potential in indications such as wound healing.

Understanding the Central Role of Citrate in the Metabolism of Cancer Cells and Tumors: An Update

Citrate plays a central role in cancer cells’ metabolism and regulation. Derived from mitochondrial synthesis and/or carboxylation of α-ketoglutarate, it is cleaved by ATP-citrate lyase into acetyl-CoA and oxaloacetate. The rapid turnover of these molecules in proliferative cancer cells maintains a low-level of citrate, precluding its retro-inhibition on glycolytic enzymes. In cancer cells relying on glycolysis, this regulation helps sustain the Warburg effect. In those relying on an oxidative metabolism, fatty acid β-oxidation sustains a high production of citrate, which is still rapidly converted into acetyl-CoA and oxaloacetate, this latter molecule sustaining nucleotide synthesis and gluconeogenesis. Therefore, citrate levels are rarely high in cancer cells. Resistance of cancer cells to targeted therapies, such as tyrosine kinase inhibitors (TKIs), is frequently sustained by aerobic glycolysis and its key oncogenic drivers, such as Ras and its downstream effectors MAPK/ERK and PI3K/Akt. Remarkably, in preclinical cancer models, the administration of high doses of citrate showed various anti-cancer effects, such as the inhibition of glycolysis, the promotion of cytotoxic drugs sensibility and apoptosis, the neutralization of extracellular acidity, and the inhibition of tumors growth and of key signalling pathways (in particular, the IGF-1R/AKT pathway). Therefore, these preclinical results support the testing of the citrate strategy in clinical trials to counteract key oncogenic drivers sustaining cancer development and resistance to anti-cancer therapies.

A novel prognostic mRNA/miRNA signature for esophageal cancer and its immune landscape in cancer progression

Mounting evidence shows that MicroRNAs (miRNAs) and their target genes are aberrantly expressed in many cancers and are linked to tumor occurrence and progression, especially in esophageal cancer (EC). This study purposed to explore new biomarkers related to the prognosis of EC and to uncover their potential mechanisms in promoting tumor progression. We identified 162 differentially expressed miRNAs and 4555 differentially expressed mRNAs in EC. Then, a risk model involving three miRNAs (miR‐4521, miR‐3682‐3p, and miR‐1269a) was designed to predict prognosis in EC patients. Furthermore, 7 target genes (Rho GTPase‐activating protein 24, Chromobox 3, Contactin‐associated protein 2, ELOVL fatty acid elongase 5, LIF receptor subunit alpha, transmembrane protein 44, and transmembrane protein 67) were selected for Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses to reveal their potential mechanisms in promoting EC progression. After a series of correlation analyses, miRNA target genes were found to be significantly positively or negatively associated with immune infiltration, tumor microenvironment, cancer stemness properties, and tumor mutation burden at different degrees in EC. To further elucidate the role of miRNA signature in cancer progression, we performed a pan‐cancer analysis to determine whether these genes exert similar effects on other tumors. Interestingly, the miRNA target genes altered expression on tumor immunity; however, pan‐cancer progression was the same as that of EC. Thus, we explored the immune landscape of the miRNA signature and its target genes in EC and pan‐cancer. These findings demonstrated the versatility and effectiveness of our model in various cancers and provided a new direction for cancer management.

Citric acid promoted melanin synthesis in B16F10 mouse melanoma cells, but inhibited it in human epidermal melanocytes and HMV-II melanoma cells via the GSK3β/β-catenin signaling pathway

Melanin, a pigment synthesized by melanocytes in the skin, resists the damage caused by ultraviolet rays to cells. Citric acid, a well-known food additive, is commonly used as an antioxidant and is an important part of the tricarboxylic acid (TCA) cycle for energy production during cellular metabolism. Here, we aimed to investigate whether the addition of excess citric acid regulates melanin synthesis, and to delineate the underlying mechanism. First, we observed that citric acid exerts opposite redox effects on mouse and human cells. Interestingly, treatment with excess citric acid increased the melanin content in mouse cells but decreased it in human cells. Furthermore, the expression of factors important for melanin synthesis, such as microphthalmia-associated transcription factor (MITF), was also regulated by citric acid treatment-it was promoted in mouse cells and suppressed in human cells. Citric acid also impacted the upstream regulators of MITF, glycogen synthase kinase 3β (GSK3β), and β-catenin. Second, we determined the importance of GSK3β in the citric acid-mediated regulation of melanin synthesis, using a GSK3β inhibitor (BIO). To the best of our knowledge, this is the first study to show that citric acid regulates melanin synthesis via the GSK3β/β-catenin signaling pathway, and that equal amounts of exogenous citric acid exert opposing effects on mouse and human cells.

Repositioned Drugs for Chagas Disease Unveiled via Structure-Based Drug Repositioning

Chagas disease, caused by the parasite Trypanosoma cruzi, affects millions of people in South America. The current treatments are limited, have severe side effects, and are only partially effective. Drug repositioning, defined as finding new indications for already approved drugs, has the potential to provide new therapeutic options for Chagas. In this work, we conducted a structure-based drug repositioning approach with over 130,000 3D protein structures to identify drugs that bind therapeutic Chagas targets and thus represent potential new Chagas treatments. The screening yielded over 500 molecules as hits, out of which 38 drugs were prioritized following a rigorous filtering process. About half of the latter were already known to have trypanocidal activity, while the others are novel to Chagas disease. Three of the new drug candidates—ciprofloxacin, naproxen, and folic acid—showed a growth inhibitory activity in the micromolar range when tested ex vivo on T. cruzi trypomastigotes, validating the prediction. We show that our drug repositioning approach is able to pinpoint relevant drug candidates at a fraction of the time and cost of a conventional screening. Furthermore, our results demonstrate the power and potential of structure-based drug repositioning in the context of neglected tropical diseases where the pharmaceutical industry has little financial interest in the development of new drugs.

Comparison of anticarcinogenic properties of Viburnum opulus and its active compound p-coumaric acid on human colorectal carcinoma

Resistance to therapeutic agents and the highly toxic side effects of synthetic drugs has spurred new research in the treatment of colon cancer, which has high morbidity and mortality ratios. This study aims to clarify the molecular mechanisms of the anticarcinogenic properties of methanol extract of Viburnum opulus L. (EVO)and its main active compound, trans-p -coumaric acid ( p -CA), on human colon cancer cells (DLD-1, HT-29, SW-620, Caco-2) and healthy colon epithelial cells (CCD-18Co). The effects of EVO on controlled cell death (apoptosis) and the cell division cycle were determined by flow cytometry. Alteration in mRNA and protein expressions of switch genes in colorectal carcinoma (APC, MLH1, TP53, SMAD4, KRAS, and BRAF) were determined by qRT-PCR and Western blot, respectively. Our results show that EVO possesses a strong reducing capacity and free-radical scavenging activity. HPLC analyses prove that p -CAis the main compound of EVO. EVO and p -CA inhibit the proliferation of human colon cancer cells DLD-1 and HT-29 in a dose-dependent manner. EVO increases apoptosis of DLD-1 cells and halts the cell cycle in the G2 stage in HT-29 cells. mRNA and protein expressions of p53 and SMAD-4 are upregulated, while BRAFs are downregulated. The results were directly proportional to p -CA. EVO and p -CA up- and downregulate switch genes and protein expressions of DLD-1 cells, which alter the expression of 186 other genes. This is the first study of pharmacological exploration of V.opulus in human colon cancer. Its antiproliferative effects may be due to the presence of p -CA.

Impact of Deep Eutectic Solvents on Extraction of Polyphenols from Grape Seeds and Skin

In the past few years, research efforts have focused on plant exploitation for deriving some valuable compounds. Extraction has been usually performed using petrochemical and volatile organic solvents, but nowadays, increased recognition of environmental pollution has prompted the utilization of green solvents as alternatives. Therefore, the aim of the present study was to exploit deep eutectic solvents (DES) (choline chloride: citric acid and choline chloride: glucose) as solvents for extracting valuable phenolic antioxidants from grapes. Investigation was conducted on ten grape varieties, observing seeds and skin as different matrix. Total polyphenol content (TPC) was determined by Folin-Ciocalteu spectrophotometric microassay. Antioxidant activity was investigated using four different tests and results were combined in a unique Antioxidant Composite Index (ACI) to reveal comprehensive information about this biological activity. Polyphenol compounds were identified and quantified with the aim of HPLC-diode array detector (DAD). Overall results support that DES (particularly choline chloride: citric acid) were comparable to conventional solvent, and in most cases even outperformed acidified aqueous ethanol (concerning extraction efficiency and antioxidant activity). Regardless of varietal distinctions, grape seeds have higher antioxidant capacity compared to grape skin, and such findings are according to their phenol compound concentrations.

Surgery/Anesthesia disturbs mitochondrial fission/fusion dynamics in the brain of aged mice with postoperative delirium

Postoperative delirium (POD) is a common complication following surgery and anesthesia (Surgery/Anesthesia). Mitochondrial dysfunction, which is demonstrated by energy deficits and excessively activated oxidative stress, has been reported to contribute to POD. The dynamic balance between mitochondrial fusion and fission processes is critical in regulating mitochondrial function. However, the impact of Surgery/Anesthesia on mitochondrial fusion/fission dynamics remains unclear. Here, we evaluate the effects of laparotomy under 1.4% isoflurane anesthesia for 2 hours on mitochondrial fission/fusion dynamics in the brain of aged mice. Mice in Surgery/Anesthesia group showed unbalanced fission/fusion dynamics, with decreased DISC1 expression and increased expression of Drp1 and Mfn2 in the mitochondrial fraction, leading to excessive mitochondrial fission and disturbed mitochondrial morphogenesis in the hippocampus and prefrontal cortex. In addition, surgical mice presented mitochondrial dysfunction, demonstrated by abnormally activated oxidative stress (increased ROS level, decreased SOD level) and energy deficits (decreased levels of ATP and MMP). Surgery/Anesthesia also decreased the expression of neuronal/synaptic plasticity-related proteins such as PSD-95 and BDNF. Furthermore, Surgery/Anesthesia induced delirium-like behavior in aged mice. In conclusion, Surgery/Anesthesia disturbed mitochondrial fission/fusion dynamics and then impaired mitochondrial function in the brain of aged mice; these effects may be involved in the underlying mechanism of POD.

MicroRNA-550a is associated with muscle system conferring poorer survival for esophageal cancer

Background Esophageal cancer (ESCA) is one of the most common cancers in the digestive tract. Approximately 300000 people on an average die of ESCA per year worldwide. The determination of key microRNAs for the prognosis of ESCA is of indispensable significance in the clinical treatment. Methods The differentially expressed microRNAs were screened by analyzing The Cancer Genome Atlas (TCGA) database. By using the survival data of the database, we analyzed correlation between patients’ survival time and miR-550a expression levels. Differential expression analysis and gene set enrichment analysis were performed using the targeted data. Results It was found that patients with high miR-550a expression levels had shorter survival time. Data mining and signal pathway enrichment analysis of TCGA database showed that abnormal miR-550a expressions affected the recurrence of tumors by the muscle system regulation. Conclusions Through the proposed investigation, miR-550a is found to be a potential biomarker as well as non-coding therapeutic target for esophagus cancer. These results suggest that miR-550a may serve as a therapeutic target and predictor for ESCA survival.

Citric Juice-mediated Synthesis of Tellurium Nanoparticles with Antimicrobial and Anticancer Properties

Bacterial infections and cancer are two of the most significant concerns that the current healthcare system should tackle nowadays. Green nanotechnology is presented as a feasible solution that is able to produce materials with significant anticancer and antibacterial activity, while overcoming the main limitations of traditional synthesis. In the present work, orange, lemon and lime extracts were used as both reducing and capping agents for the green synthesis of tellurium nanoparticles (TeNPs) using a microwave-assisted reaction. TeNPs showed a uniform size distribution, and rod- and cubic-shapes, and were extensively characterized in terms of morphology, structure and composition using TEM, SEM, XPS, XRD, FTIR and EDX analysis. TeNPs showed an important antibacterial activity against both Gram-negative and -positive bacteria in a range concentrations from 5 to 50 μg/mL over a 24-hour time period. Besides, nanoparticles showed anticancer effect towards human melanoma cells over 48 hours at concentrations up to 50 μg/mL. Moreover, the Te nanostructures showed no significant cytotoxic effect towards human dermal fibroblast at concentrations up to 50 μg/mL. Therefore, we present an environmentally-friendly and cost-effective synthesis of TeNPs using only fruit juices and showing enhanced and desirable biomedical properties towards both infectious diseases and cancer.

Loss of Tctn3 causes neuronal apoptosis and neural tube defects in mice

Tctn3 belongs to the Tectonic (Tctn) family and is a single-pass membrane protein localized at the transition zone of primary cilia as an important component of ciliopathy-related protein complexes. Previous studies showed that mutations in Tctn1 and Tctn2, two members of the tectonic family, have been reported to disrupt neural tube development in humans and mice, but the functions of Tctn3 in brain development remain elusive. In this study, Tctn3 knockout (KO) mice were generated by utilizing the piggyBac (PB) transposon system. We found that Tctn3 KO mice exhibited abnormal global development, including prenatal lethality, microphthalmia, polysyndactyly, and abnormal head, sternum, and neural tube, whereas Tctn3 heterozygous KO mice did not show abnormal development or behaviors. Further, we found that the mRNA levels of Gli1 and Ptch1, downstream signaling components of the Shh pathway, were significantly reduced. Likewise, neural tube patterning-related proteins, such as Shh, Foxa2, and Nkx2.2, were altered in their distribution. Interestingly, Tctn3 KO led to significant changes in apoptosis-related proteins, including Bcl-2, Bax, and cleaved PARP1, resulting in reduced numbers of neuronal cells in embryonic brains. Tctn3 KO inhibited the PI3K/Akt signaling pathway but not the mTOR-dependent pathway. The small molecule SC79, a specific Akt activator, blocked apoptotic cell death in primary mouse embryonic fibroblasts from Tctn3 KO mice. Finally, NPHP1, a protein with anti-apoptotic ability, was found to form a complex with Tctn3, and its levels were decreased in Tctn3 KO mice. In conclusion, our results show that Tctn3 KO disrupts the Shh signaling pathway and neural tube patterning, resulting in abnormal embryonic development, cellular apoptosis, and prenatal death in mice.