Taurine Enhances Anticancer Activity of Cisplatin in Human Cervical Cancer Cells

Investigation of a novel Schiff base Catena-((μ6-(E)-2-((4-methoxy-2-oxidobenzylidene)ammonio)ethane-1-sulfonato potassium as a potential antibacterial agent

CONTEXT

Schiff bases, which have intriguing properties in many areas, have been studied extensively in recent years due to their structural properties and biological activities. In this research, a novel water-soluble Schiff base complex, Catena-((μ6-(E)-2-((4-methoxy-2-oxidobenzylidene) ammonio) ethane-1-sulfonato potassium, C10H14KNO6S (CMOAESP), was synthesized by a one-step condensation reaction of 2-hydroxy-4-methoxy benzaldehyde and taurine with the yield of 65%, 0.333 g. Spectral analysis of water-soluble crude product showed equilibria keto-enol tautomerism, by a resulting Zwitterionic form of the structure. The ADMET prediction showed that the CMOAESP obeys Lipinski's rule and was in bioavability range. The molecular docking results showed an inhibition ability for 1JIJ and MBT1 proteins which play an important role in antibacterial studies. The experimental end theoretical calculations were in a good agreement that CMOASP has inhibition efficiency against Escherichia coli and has inhibition at high concentrations against Staphylococcaceae aureus.

METHODS

The WinGX software system SHELXS direct technique was used to solve the structure, and SHELXL full-matrix least-squares approach on F2 was used to refine the results. The Gaussian 09W program was used to carry out the DFT calculations. The gap values for CMOAESP were calculated by using the B3LYP/6- 311 + + G(d,p) method in order to predict its reactivities and behaviors in the gas phase. The frontier orbitals, LUMO and HOMO together with some global parameters as electronegativity (μ), chemical potential (χ), hardness (η), electrophilicity index (ω), and softness (S) values were predicted from DFT calculations.

Impact of the redox-active MnTnHex-2-PyP5+ and cisplatin on the metabolome of non-small cell lung cancer cells

Redox-based cancer therapeutic strategies aim to raise reactive oxygen species (ROS) levels in cancer cells, thus modifying their redox status, and eventually inducing cell death. Promising compounds, known as superoxide dismutase mimics (SODm), e.g. MnTnHex-2-Py5+ (MnTnHex), could increase intracellular H2O2 in cancer cells with deficient ROS removal systems and therefore enhance radio- and chemotherapy efficacy. We have previously shown that MnTnHex was cytotoxic either alone or combined with cisplatin to non-small cell lung cancer (NSCLC) cells. To gain a deeper understanding of the effects and safety of this compound, it is crucial to analyze the metabolic alterations that take place within the cell. Our goal was thus to study the intracellular metabolome (intracellular metabolites) of NSCLC cells (A549 and H1975) using nuclear magnetic resonance (NMR) spectroscopy-based metabolomics to evaluate the changes in cellular metabolism upon exposure to MnTnHex per se or in combination with cisplatin. 1H NMR metabolomics revealed a higher number of significantly altered metabolites in A549 cells exposed to MnTnHex alone or combined with cisplatin in comparison with non-treated cells (nine dysregulated metabolites), suggesting an impact on aminoacyl-tRNA biosynthesis, glycolysis/gluconeogenesis, taurine, hypotaurine, glycerophospholipid, pyruvate, arginine and proline metabolisms. Regarding H1975 cells, significant alterations in the levels of six metabolites were observed upon co-treatment with MnTnHex and cisplatin, suggesting dysregulations in aminoacyl-tRNA biosynthesis, arginine and proline metabolism, pyruvate metabolism, and glycolysis/gluconeogenesis. These findings help us to understand the impact of MnTnHex on NSCLC cells. Importantly, specific altered metabolites, such as taurine, may contribute to the chemosensitizing effects of MnTnHex.

Opuntia ficus-indica (L.) Mill. - anticancer properties and phytochemicals: current trends and future perspectives

Cancer is a leading cause of mortality worldwide, and conventional cancer therapies such as chemotherapy and radiotherapy often result in undesirable and adverse effects. Natural products have emerged as a promising alternative for cancer treatment, with comparatively fewer side effects reported. Opuntia ficus-indica (L.) Mill., a member of the Cactaceae family, contains a diverse array of phytochemicals, including flavonoids, polyphenols, betalains, and tannins, which have been shown to exhibit potent anticancer properties. Various parts of the Opuntia plant, including the fruits, stems/cladodes, and roots, have demonstrated cytotoxic effects against malignant cell lines in numerous studies. This review comprehensively summarizes the anticancer attributes of the phytochemicals found in Opuntia ficus-indica (L.) Mill., highlighting their potential as natural cancer prevention and treatment agents. Bibliometric metric analysis of PubMed and Scopus-retrieved data using VOSviewer as well as QDA analysis provide further insights and niche to be explored. Most anticancer studies on Opuntia ficus-indica and its purified metabolites are related to colorectal/colon cancer, followed by melanoma and breast cancer. Very little attention has been paid to leukemia, thyroid, endometrial, liver, and prostate cancer, and it could be considered an opportunity for researchers to explore O. ficus-indica and its metabolites against these cancers. The most notable mechanisms expressed and validated in those studies are apoptosis, cell cycle arrest (G0/G1 and G2/M), Bcl-2 modulation, antiproliferative, oxidative stress-mediated mechanisms, and cytochrome c. We have also observed that cladodes and fruits of O. ficus-indica have been more studied than other plant parts, which again opens the opportunity for the researchers to explore. Further, cell line-based studies dominated, and very few studies were related to animal-based experiments. The Zebrafish model is another platform to explore. However, it seems like more in-depth studies are required to ascertain clinical utility of this biosustainable resource O. ficus-indica.

Metabolic Profiling of Bladder Cancer Patients' Serum Reveals Their Sensitivity to Neoadjuvant Chemotherapy

Numerous patients with muscle-invasive bladder cancer develop low responsiveness to cisplatin. Our purpose was to explore differential metabolites derived from serum in bladder cancer patients treated with neoadjuvant chemotherapy (NAC). Data of patients diagnosed with cT2-4aNxM0 was collected. Blood samples were retained prospectively before the first chemotherapy for untargeted metabolomics by ¹H-NMR and UPLC-MS. To identify characterized metabolites, multivariate statistical analyses were applied, and the intersection of the differential metabolites discovered by the two approaches was used to identify viable biomarkers. A total of 18 patients (6 NAC-sensitive patients and 12 NAC-resistant patients) were enrolled. There were 29 metabolites detected by ¹H-NMR and 147 metabolites identified by UPLC-MS. Multivariate statistics demonstrated that in the sensitive group, glutamine and taurine were considerably increased compared to their levels in the resistant group, while glutamate and hypoxanthine were remarkably decreased. Pathway analysis and enrichment analysis showed significant alterations in amino acid pathways, suggesting that response to chemotherapy may be related to amino acid metabolism. In addition, hallmark analysis showed that DNA repair played a regulatory role. Overall, serum metabolic profiles of NAC sensitivity are significantly different in bladder cancer patients. Glycine, hypoxanthine, taurine and glutamine may be the potential biomarkers for clinical treatment. Amino acid metabolism has potential value in enhancing drug efficacy.

The role of taurine on chemotherapy-induced cardiotoxicity: A systematic review of non-clinical study

AIMS

Although chemotherapeutic agents have highly beneficial effects against cancer, they disturb the body's normal homeostasis. One of the critical side effects of chemotherapeutic agents is their deleterious effect on the cardiac system, which causes limitations of their clinical usage. Taurine constitutes more than 50% of the amino acids in the heart. The use of taurine might prevent chemotherapy-induced cardiotoxicity. This systematic study aims to evaluate the protective role of taurine against cardiotoxicity induced by chemotherapy.

METHODS

A systematic search was performed in databases up to November 2020, and the review is designed on PRISMA guidelines. The search keywords were selected based on our study target and were searched in the title and abstract. After the consecutive screening, out of a whole of 94 articles, 8 articles were included according to our inclusion and exclusion criteria.

KEY FINDINGS

According to the study results, chemotherapy decreases body and heart weight and increases mortality. Also, it induces some biochemical and histological changes compared to the control group. By co-administration of taurine with chemotherapy, alterations returned near to the average level. These protective effects of taurine are mediated through anti-oxidant, anti-inflammatory, and anti-apoptotic properties.

SIGNIFICANCE

Based on evaluated non-clinical studies, taurine ameliorates chemotherapy-induced cardiotoxicity, but its possible interaction with the efficacy of anti-cancer medicines that mostly act through induction of oxidants remains to be elucidated in the future. This needs conducting well-designed studies to assess the effectiveness and safety of this combination simultaneously.

The Anti-Inflammatory Effect of Taurine on Cardiovascular Disease

Taurine is a non-protein amino acid that is expressed in the majority of animal tissues. With its unique sulfonic acid makeup, taurine influences cellular functions, including osmoregulation, antioxidation, ion movement modulation, and conjugation of bile acids. Taurine exerts anti-inflammatory effects that improve diabetes and has shown benefits to the cardiovascular system, possibly by inhibition of the renin angiotensin system. The beneficial effects of taurine are reviewed.

Role of taurine, its haloamines and its lncRNA TUG1 in both inflammation and cancer progression. On the road to therapeutics? (Review)

For one century, taurine is considered as an end product of sulfur metabolism. In this review, we discuss the beneficial effect of taurine, its haloamines and taurine upregulated gene 1 (TUG1) long non‑coding RNA (lncRNA) in both cancer and inflammation. We outline how taurine or its haloamines (N‑Bromotaurine or N‑Chlorotaurine) can induce robust and efficient responses against inflammatory diseases, providing insight into their molecular mechanisms. We also provide information about the use of taurine as a therapeutic approach to cancer. Taurine can be combined with other chemotherapeutic drugs, not only mediating durable responses in various malignancies, but also circumventing the limitations met from chemotherapeutic drugs, thus improving the therapeutic outcome. Interestingly, the lncRNA TUG1 is regarded as a promising therapeutic approach, which can overcome acquired resistance of cancer cells to selected strategies. In this regard, we can translate basic knowledge about taurine and its TUG1 lncRNA into potential therapeutic options directed against specific oncogenic signaling targets, thereby bridging the gap between bench and bedside.

Impact of Taurine on the proliferation and apoptosis of human cervical carcinoma cells and its mechanism

BACKGROUND

Cervical cancer has the fourth highest incidence and mortality rate of all cancers in women worldwide; it seriously harms their physical and mental health. The aim of this study was to observe the roles and preliminary mechanism of Taurine (Tau)-induced apoptosis in cervical cancer cells.

METHODS

Cells from the human cervical cancer cell line SiHa were transfected with the recombinant plasmid pEGFP-N1-MST1 (mammalian sterile 20-like kinase 1); then, the cell proliferation activity was analyzed by the MTT assay, cell apoptosis by flow cytometry, and the related protein levels by Western blotting.

RESULTS

Tau inhibited the proliferation of SiHa cells and induced apoptosis in these cells (the apoptotic rate was 21.95% in the Tau 160 mmol/L group and 30% in the Tau 320 mmol/L group), upregulated the expression of the MST1 (control, 0.53; Tau 40-320 mmol/L groups, 0.84-1.45) and Bax (control, 0.45; Tau 40-320 mmol/L groups, 0.64-1.51) proteins (P < 0.01), and downregulated the expression of Bcl-2 (control, 1.28, Tau 40-320 mmol/L groups, 0.93-0.47) (P < 0.01). The overexpression of MST1 promoted the apoptosis of SiHa cells, enhanced the apoptosis-inductive effects of Tau (P < 0.01), upregulated the expression of the proapoptotic proteins p73, p53, PUMA (p53 upregulated modulator of apoptosis), and caspase-3, and promoted the phosphorylation of YAP (Yes-associated protein).

CONCLUSIONS

Tau inhibited the proliferation and induced the apoptosis of cervical cancer SiHa cells. The MST1 protein plays an important role in the Tau-induced apoptosis of cervical cancer cells.

Liver Antioxidant Enzyme Activities Increase After Taurine in Ovariectomized Rats

The present study was performed to know the effects of taurine on the lipid level of plasma and liver, lipid peroxidation and antioxidative enzyme activities of liver tissue in ovariectomized (OVX) rats fed cholesterol. Twenty-four female SD rats (200 ± 5 g) were grouped; sham and ovariectomy groups, which were each randomly subgrouped; fed control and control supplemented with taurine (20 g/kg diet). The serum total cholesterol, TG (triglyceride), LDL-cholesterol, athrogenic index, and HDL-cholesterol of taurine diet group were not statistically different. Also the levels of liver total cholesterol, triglyceride were not considerably different in different diets. The lipid peroxidation of malondialdehyde concentration was considerably lower in taurine-feeding group than control-feeding group in ovariectomy group. The superoxide dismutase activity in liver tissue was significantly higher in rats fed taurine than in rats fed control diet in OVX rats. GSH-Px (glutathione peroxidase) activity was statistically greater at the rats fed taurine diets compared to rats fed control diet in ovariectomy group. Activity of catalase was higher in taurine group than in control group in ovariectomy group, but it was not significantly different. In conclusion, taurine supplementation was beneficial on antioxidative enzyme activities of liver tissue in ovariectomized rats fed cholesterol.

Effect of taurine on cell proliferation and apoptosis human lung cancer A549 cells

To investigate the effects of taurine on cell proliferation and apoptosis, the human lung cancer A549 cell line and xenograft tumors in nude mice were used. The effects of taurine on cell proliferation and apoptosis were observed at time points of 24, 48 and 72 h after treatment using an MTT assay to detect the survival rate, and flow cytometry to detect the apoptotic rate. Western blot analysis was performed to examine the levels of p53 upregulated modulator of apoptosis (PUMA), BCL2, apoptosis regulator (Bcl-2) and BCL2-associated X, apoptosis regulator (Bax) in A549 cells. The level of PUMA, Bax and Bcl-2 proteins in the mouse xenograft tumors treated with taurine and/or exogenous PUMA were assessed by immunohistochemistry, with taurine suppressing the proliferation of the human lung cancer A549 cell line in a concentration-dependent manner, and it significantly enhanced the apoptosis rate at all concentrations. Taurine induced the significant upregulation of PUMA and Bax, but led to downregulation of Bcl-2. In comparison to the control group, taurine treatment markedly reduced the volume and weight of A549-derived xenograft tumors in nude mice. Expression of PUMA and Bax were upregulated in the xenograft tumors following taurine treatment, whereas Bcl-2 was downregulated. In addition, the inhibitory effect of taurine and exogenous PUMA on tumor growth was significantly higher than that of a single treatment of taurine or exogenous PUMA. It can therefore be concluded that taurine can inhibit cell proliferation of the human lung cancer A549 cell line and the growth of the xenograft tumors, whereas PUMA serves an important role in taurine-induced growth suppression.

Plasma-free amino acid profiles are predictors of cancer and diabetes development

Type 2 diabetes (T2D) and cancers are two major causes of morbidity and mortality worldwide. Nowadays, there is convincing evidence of positive associations between T2D and the incidence or prognosis of a wide spectrum of cancers, for example, breast, colon, liver and pancreas. Many observational studies suggest that certain medications used to treat hyperglycemia (or T2D) may affect cancer cells directly or indirectly. The potential mechanisms of the direct T2D cancer links have been hypothesized to be hyperinsulinemia, hyperglycemia and chronic inflammation; however, the metabolic pathways that lead to T2D and cancers still remain elusive. Plasma-free amino acid (PFAA) profiles have been highlighted in their associations with the risks of developing T2D and cancers in individuals with different ethnic groups and degree of obesity. The alterations of PFAAs might be predominately caused by the metabolic shift resulted from insulin resistance. The underlying mechanisms have not been fully elucidated, in particular whether the amino acids are contributing to these diseases development in a causal manner. This review addresses the molecular and clinical associations between PFAA alterations and both T2D and cancers, and interprets possible mechanisms involved. Revealing these interactions and mechanisms may improve our understanding of the complex pathogenesis of diabetes and cancers and improve their treatment strategies.

N-bromotaurine surrogates for loss of antiproliferative response and enhances cisplatin efficacy in cancer cells with impaired glucocorticoid receptor

Glucocorticoids (GCs) are frequently used in anticancer combination regimens; however, their continuous use adds selective pressure on cancer cells to develop GC-resistance via impairment of the glucocorticoid receptor (GR), therefore creating a need for GC-alternatives. Based on the drug repurposing approach and the commonalities between inflammation and neoplasia, drugs that are either in late-stage clinical trials and/or already marketed for GC-refractory inflammatory diseases could be evaluated as GC-substitutes in the context of cancer. Advantageously, unlike new molecular entities currently being de novo developed to restore GC-responsiveness of cancer cells, such drugs have documented safety and efficacy profile, which overall simplifies their introduction in clinical cancer trials. In this study, we estimated the potential of a well-established, multistage, cell line-based, mouse skin carcinogenesis model to be exploited as an initial screening tool for unveiling covert GC-substitutes. First, we categorized the cell lines of this model to GC-sensitive and GC-resistant, in correlation with their corresponding GR status, localization, and functionality. We found that GC-resistance starts in papilloma stages, due to a dysfunctional GR, which is overexpressed, DNA binding-competent, but transactivation-incompetent in papilloma, squamous, and spindle stages of the model. Then, aided by this tool, we evaluated the ability of N-bromotaurine, a naturally occurring, small-molecule, nonsteroid anti-inflammatory drug which is under consideration for use interchangeably/in replacement to GCs in skin inflammations, to restore antiproliferative response of GC-resistant cancer cells. Unlike GCs, N-bromotaurine inhibited cell-cycle progression in GC-resistant cancer cells and efficiently synergized with cisplatin, thus indicating a potential to be exploited instead of GCs against cancer.

Effect of taurine on the proliferation and apoptosis of human hepatocellular carcinoma HepG2 cells

The aim of the present study was to observe the effect and molecular mechanism of taurine (Tau) on the cell proliferation and apoptosis of human hepatocellular carcinoma (HHCC) HepG2 cells. HHCC HepG2 cells were used as target cells, and the cell survival rate was assessed using a multi-time-step method. The p53 upregulated modulator of apoptosis (PUMA) gene was transiently transfected by lipofection and subsequently silenced with specific small interfering (si)RNA. The cell apoptosis rate was detected by flow cytometry, and protein expression levels were analyzed with western blotting. Addition of 20-160 mM Tau was shown to have a significant inhibitory effect on cell proliferation, while promoting the induction of HHCC HepG2 cell apoptosis (P<0.05). Transfection of the PUMA gene significantly enhanced the ability of Tau to inhibit proliferation and induce apoptosis of HepG2 cells. In addition, transfection of the PUMA gene increased the protein expression of B-cell lymphoma-2-associated X and reduced the expression of B-cell lymphoma-2 (P<0.05). Silencing the PUMA gene with specific siRNA was demonstrated to significantly reduce the ability of Tau to inhibit proliferation and induce the apoptosis of HHCC HepG2 cells (P<0.01). Therefore, the PUMA gene was shown to have an important role in mechanism underlying the effect that Tau exerts on cell proliferation and apoptosis in HHCC HepG2 cells.

Taurine induces the apoptosis of breast cancer cells by regulating apoptosis-related proteins of mitochondria

Taurine (Tau), the most abundant free amino acid in humans has numerous potential health benefits through its antioxidant and anti-inflammatory properties. However, limited studies have assessed its effect on tumors and the antitumor mechanism remains unknown. The present study investigated the cellular and molecular changes induced by Tau, leading to the induction of apoptosis in human breast cancer cell lines MCF-7 and MDA-MB-231. MCF-7 is p53 proficient (p53+/+) and MDA-MB-231 is a p53 null mutant (p53-/-). Cell proliferation and viability were assessed by MTT. Flow cytometry and hoechst33342 fluorescent staining were employed to detect apoptosis. Spectrophotometry was used to detect caspase-3 activity. Reverse transcription-polymerase chain reaction and western blot analysis were used to detect the levels of mRNA and proteins of p53-upregulated modulator of apoptosis (PUMA), Bax and Bcl-2. Finally, the affect of Tau on the growth of MDA-MB-231-cell-nude mice xenografts was examined. In the study, Tau inhibited growth and induced apoptosis of the two cell lines in a concentration- and time-dependent manner. Notably, the inhibitory effect of Tau on p53-/- cancer cells was clearly significant compared to the p53+/+ cancer cells. Further studies showed that Tau promoted apoptosis in human breast cancer cells and inhibited the growth of tumor in nude mice by inducing the expression of PUMA, which further up- and downregulated the expression of Bax and Bcl-2 protein, giving rise to increased activation of caspase-3. Collectively, these results indicate that Tau is a potent candidate for the chemotherapy of breast cancer through increasing the PUMA expression independent of p53 status.

Taurine rescues cisplatin-induced muscle atrophy in vitro: a morphological study

Cisplatin (CisPt) is a widely used chemotherapeutic drug whose side effects include muscle weakness and cachexia. Here we analysed CisPt-induced atrophy in C2C12 myotubes by a multidisciplinary morphological approach, focusing on the onset and progression of autophagy, a protective cellular process that, when excessively activated, may trigger protein hypercatabolism and atrophy in skeletal muscle. To visualize autophagy we used confocal and transmission electron microscopy at different times of treatment and doses of CisPt. Moreover we evaluated the effects of taurine, a cytoprotective beta-amino acid able to counteract oxidative stress, apoptosis, and endoplasmic reticulum stress in different tissues and organs. Our microscopic results indicate that autophagy occurs very early in 50  μM CisPt challenged myotubes (4 h-8 h) before overt atrophy but it persists even at 24 h, when several autophagic vesicles, damaged mitochondria, and sarcoplasmic blebbings engulf the sarcoplasm. Differently, 25 mM taurine pretreatment rescues the majority of myotubes size upon 50  μM CisPt at 24 h. Taurine appears to counteract atrophy by restoring regular microtubular apparatus and mitochondria and reducing the overload and the localization of autophagolysosomes. Such a promising taurine action in preventing atrophy needs further molecular and biochemical studies to best define its impact on muscle homeostasis and the maintenance of an adequate skeletal mass in vivo.