Caffeine increases the antitumor effect of Cisplatin in human hepatocellular carcinoma cells

Caffeine in Hepatocellular Carcinoma: Cellular Assays, Animal Experiments, and Epidemiological Investigation

The use of caffeine in treating various liver diseases has made substantial progress in the past decade owing to advances in science, technology, and medicine. However, whether caffeine has a preventive effect on hepatocellular carcinoma (HCC) and its mechanism are still worth further investigation. In this review, we summarize and analyze the efficacy and safety of caffeine in the prevention of HCC. We conducted a review of articles published in PubMed and Web of Science in the past 2 decades until December 6, 2023, which were searched for using the terms "Caffeine" and "Hepatocellular Carcinoma." Studies have found that coffee intake is negatively correlated with HCC risk, especially caffeinated coffee. Recent studies have found that caffeine has beneficial effects on liver health, decreasing levels of enzymes responsible for liver damaging and slowing the progression of hepatic fibrosis and cirrhosis. Caffeine also acts against liver fibrosis through adenosine receptors (ARs), which promote tissue remodeling by inducing fibrin and collagen production. Additionally, new studies have found that moderate consumption of caffeinated beverages can decrease various the levels of various collagens in patients with chronic hepatitis C. Furthermore, polyphenolic compounds in coffee can improve fat homeostasis, reduce oxidative stress, and prevent liver steatosis and fibrosis. Moreover, many in vitro studies have shown that caffeine can protect liver cells and inhibit the activation and proliferation of hepatic stellate cells. Taken together, we describe the benefits of caffeine for liver health and highlight its potential values as a drug to prevent various hepatic diseases. As a protective agent of liver inflammation, non-selective AR inhibitor caffeine can inhibit the growth of HCC cells by inhibiting adenosine and AR binding to initiate immune response, providing a basis for the future development of caffeine as an adjuvant drug against HCC.

Caffeine-Supplemented Diet Prevents Fatigue-Like Behavior in Tumor-Bearing Mice

Caffeine is a widely consumed stimulant, known for its positive effects on physical and mental performance. These effects are potentially beneficial for ameliorating cancer-related fatigue, which affects the quality of life of patients with cancer. This study aimed to determine the anti-fatigue and antitumor effects of caffeine in tumor-bearing mice. BALB/c mice were intravenously injected with C26 colon carcinoma cells and fed with normal or 0.05% caffeine-supplemented diet. Fatigue-like behavior was assessed by running performance using a treadmill test. Lung, blood, liver, muscle, and epididymal adipose tissue samples were collected on day 13 and examined. The antitumor effect of caffeine was assessed using subcutaneous tumor-bearing mice fed with 0.05% caffeine-supplemented diet, and the tumor volume was measured. C26 tumor-bearing mice showed fatigue-like behavior associated with hypoglycemia, depleted liver glycogen and non-esterified fatty acid (NEFA) levels. C26 tumor-bearing mice fed with 0.05% caffeine-supplemented diet showed improved running performance associated with restored NEFA levels. However, exacerbated hypoglycemia and liver glycogen levels after caffeine consumption may be due to tumor-induced catabolic signals, as the tumor volume was not affected. Collectively, caffeine may exert anti-fatigue effects through enhanced lipolysis leading to restored NEFA levels, which can be used as an alternative energy source.

Caffeine in liver diseases: Pharmacology and toxicology

We have previously shown that adenosine A1AR antagonists, adenosine A2aAR antagonists, and caffeine have significant inhibitory effects on the activation and proliferation of hepatic stellate cells in alcoholic liver fibrosis. Many recent studies have found that moderate coffee consumption is beneficial for various liver diseases. The main active ingredient of coffee is caffeine, which is a natural non-selective adenosine receptor antagonist. Moreover, numerous preclinical epidemiological studies and clinical trials have examined the association between frequent coffee consumption and the risk of developing different liver diseases. In this review, we summarize and analyze the prophylactic and therapeutic effects of caffeine on various liver diseases, with an emphasis on cellular assays, animal experiments, and clinical trials. To review the prevention and treatment effects of caffeine on different liver diseases, we searched all literature before 19 July 2022, using “caffeine” and “liver disease” as keywords from the PubMed and ScienceDirect databases. We found that moderate coffee consumption has beneficial effects on various liver diseases, possibly by inhibiting adenosine binding to its receptors. Caffeine is a potential drug for the prevention and treatment of various liver diseases.

Caffeine Enhances the Toxicity of Platinum-Based Drugs at the Molecular Level Even Outside of the Intracellular Environment: A Single-Molecule Force Spectroscopy Study

It is well reported in the literature that caffeine, the most consumed alkaloid around the world, enhances the anticancer effects of the drug cisplatin by inhibiting DNA repair by the cellular machinery. Here, we perform single-molecule force spectroscopy assays with optical tweezers to show that caffeine enhances the toxicity not only of cisplatin but also of various different platinum-based drugs already at the molecular level, using samples containing only double-stranded (ds)DNA, platinum drugs, and the alkaloid in a simple phosphate buffer, that is, completely out of the complex environment found inside real living cells. In fact, our results show that caffeine acts as an allosteric catalyst which increases the effective equilibrium binding constant between DNA and the platinum drugs, also interfering in the cooperativity of the binding reactions. To the best of our knowledge, this is the first time that such a property of caffeine was demonstrated and characterized from a pure physicochemical perspective, outside the cellular environment. Thus, the present work provides new insights into the use of this alkaloid for current chemotherapeutic applications.

The Role of Bitter Taste Receptors in Cancer: A Systematic Review

BACKGROUND

Since it is known that bitter taste receptors (TAS2Rs) are expressed and functionally active in various extra-oral cells, their genetic variability and functional response initiated by their activation have become of broader interest, including in the context of cancer.

METHODS

A systematic research was performed in PubMed and Google Scholar to identify relevant publications concerning the role of TAS2Rs in cancer.

RESULTS

While the findings on variations of TAS2R genotypes and phenotypes and their association to the risk of developing cancer are still inconclusive, gene expression analyses revealed that TAS2Rs are expressed and some of them are predominately downregulated in cancerous compared to non-cancerous cell lines and tissue samples. Additionally, receptor-specific, agonist-mediated activation induced various anti-cancer effects, such as decreased cell proliferation, migration, and invasion, as well as increased apoptosis. Furthermore, the overexpression of TAS2Rs resulted in a decreased tumour incidence in an in vivo study and TAS2R activation could even enhance the therapeutic effect of chemotherapeutics in vitro. Finally, higher expression levels of TAS2Rs in primary cancerous cells and tissues were associated with an improved prognosis in humans.

CONCLUSION

Since current evidence demonstrates a functional role of TAS2Rs in carcinogenesis, further studies should exploit their potential as (co-)targets of chemotherapeutics.

Identifying the biomarkers and pathways associated with hepatocellular carcinoma based on an integrated analysis approach

BACKGROUND AND AIMS

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death worldwide. The molecular mechanism underlying HCC is still unclear. In this study, we conducted a comprehensive analysis to explore the genes, pathways and their interactions involved in HCC.

METHODS

We analysed the gene expression datasets corresponding to 488 samples from 10 studies on HCC and identified the genes differentially expressed in HCC samples. Then, the genes were compared against Phenolyzer and GeneCards to screen those potentially associated with HCC. The features of the selected genes were explored by mapping them onto the human protein-protein interaction network, and a subnetwork related to HCC was constructed. Hub genes in this HCC specific subnetwork were identified, and their relevance with HCC was investigated by survival analysis.

RESULTS

We identified 444 differentially expressed genes (177 upregulated and 267 downregulated) related to HCC. Functional enrichment analysis revealed that pathways like p53 signalling and chemical carcinogenesis were eriched in HCC genes. In the subnetwork related to HCC, five disease modules were detected. Further analysis identified six hub genes from the HCC specific subnetwork. Survival analysis showed that the expression levels of these genes were negatively correlated with survival rate of HCC patients.

CONCLUSIONS

Based on a systems biology framework, we identified the genes, pathways, as well as the disease specific network related to HCC. We also found novel biomarkers whose expression patterns were correlated with progression of HCC, and they could be candidates for further investigation.

Denatonium as a Bitter Taste Receptor Agonist Modifies Transcriptomic Profile and Functions of Acute Myeloid Leukemia Cells

The contribution of cell-extrinsic factors in Acute Myeloid Leukemia (AML) generation and persistence has gained interest. Bitter taste receptors (TAS2Rs) are G protein-coupled receptors known for their primary role as a central warning signal to induce aversion toward noxious or harmful substances. Nevertheless, the increasing amount of evidence about their extra-oral localization has suggested a wider function in sensing microenvironment, also in cancer settings. In this study, we found that AML cells express functional TAS2Rs. We also highlighted a significant association between the modulation of some TAS2Rs and the poor-prognosis AML groups, i.e., TP53- and TET2-mutated, supporting a potential role of TAS2Rs in AML cell biology. Gene expression profile analysis showed that TAS2R activation with the prototypical agonist, denatonium benzoate, significantly modulated a number of genes involved in relevant AML cellular processes. Functional assay substantiated molecular data and indicated that denatonium reduced AML cell proliferation by inducing cell cycle arrest in G0/G1 phase or induced apoptosis via caspase cascade activation. Moreover, denatonium exposure impaired AML cell motility and migratory capacity, and inhibited cellular respiration by decreasing glucose uptake and oxidative phosphorylation. In conclusion, our results in AML cells expand the observation of cancer TAS2R expression to the setting of hematological neoplasms and shed light on a role of TAS2Rs in the extrinsic regulation of leukemia cell functions.

Caffeine and Cisplatin Effectively Targets the Metabolism of a Triple-Negative Breast Cancer Cell Line Assessed via Phasor-FLIM

Triple-negative tumor cells, a malignant subtype of breast cancer, lack a biologically targeted therapy. Given its DNA repair inhibiting properties, caffeine has been shown to enhance the effectiveness of specific tumor chemotherapies. In this work, we have investigated the effects of caffeine, cisplatin, and a combination of the two as potential treatments in energy metabolism for three cell lines, triple-negative breast cancer (MDA-MB-231), estrogen-receptor lacking breast cancer (MCF7) and breast epithelial cells (MCF10A) using a sensitive label-free approach, phasor-fluorescence lifetime imaging microscopy (phasor-FLIM). We found that solely using caffeine to treat MDA-MB-231 shifts their metabolism towards respiratory-chain phosphorylation with a lower ratio of free to bound NADH, and a similar trend is seen in MCF7. However, MDA-MB-231 cells shifted to a higher ratio of free to bound NADH when cisplatin was added. The combination of cisplatin and caffeine together reduced the survival rate for MDA-MD231 and shifted their energy metabolism to a higher fraction of bound NADH indicative of oxidative phosphorylation. The FLIM and viability results of MCF10A cells demonstrate that the treatments targeted cancer cells over the normal breast tissue. The identification of energy metabolism alteration could open up strategies of improving chemotherapy for malignant breast cancer.

Caffeine citrate enhanced cisplatin antitumor effects in osteosarcoma and fibrosarcoma in vitro and in vivo

Background

While multiagent chemotherapy has dramatically improved the prognosis of sarcoma, the novel chemotherapeutics have hardly developed over the past 30 years. Caffeine can induce apoptosis, delays in cell cycle progression and can enhance the cytocidal effects of anti-cancer agents. Citrate has been reported to enhance the cytocidal effect of cisplatin in gastric cancer in vitro. However its effect in sarcoma cells had not been reported.

Methods

This study was designed to evaluate whether the addition of caffeine, citrate, or caffeine citrate to cisplatin improved its cytocidal effect (cell survival, proliferation, and apoptosis) on human osteosarcoma (HOS), human fibrosarcoma (HT1080) and murine osteosarcoma (LM8) cell lines. We also tested the various combinations in a mouse heterotopic transplantation model in vivo. In cell survival assay, combination index (CI) of caffeine citrate was calculated as a combination of anhydrous caffeine and citric acid, and the synergy was evaluated (CI < 1.0).

Results

In all cell lines, cisplatin combined with caffeine citrate significantly reinforced the anticancer effect compared with cisplatin alone, combination of cisplatin and anhydrous caffeine, and combination of cisplatin and citric acid. Moreover, CI was < 1.0 in all conditions. The anticancer agent reinforcement effect of caffeine citrate was synergy of anhydrous caffeine and citric acid. In cell proliferation and cell cycle assay revealed that caffeine citrate had most strong effect as a combination drug than caffeine and citric acid in inducing G0/G1 cell-cycle arrest with subsequent suppressed cell proliferation. In mitochondrial depolarization and caspase 3/7 activity assay revealed that caffeine citrate had most strong effect as a combination drug than caffeine and citric acid in apoptosis associated with decreased mitochondrial membrane potential. In vivo, three different drug concentrations were tested, and cisplatin combined with caffeine citrate was found to have the strongest antitumor effect.

Conclusions

This is the first report demonstrating that caffeine citrate has a significantly greater potentiating effect on cisplatin than adding either caffeine or citric acid. The combination of cisplatin with caffeine citrate is a novel treatment that might hold promise for improving the outcome of osteosarcoma and fibrosarcoma, which up till now has generally not responded well to chemotherapy.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5891-y) contains supplementary material, which is available to authorized users.

DNA-binding and in vitro cytotoxic activity of platinum(II) complexes of curcumin and caffeine

Three Pt(II) complexes containing the natural ligands curcumin and caffeine, namely [Pt(curc)(PPh₃)₂]Cl (1), [PtCl(curc)(DMSO)] (2) (curc = deprotonated curcumin) and trans-[Pt(caffeine)Cl₂(DMSO)] (3), were synthesized and fully characterized. The data obtained suggest that, for both 1 and 2, the anion of curcumin is coordinated to the platinum ion via the oxygen atoms of the β-diketonate moiety. Spectroscopic features reveal that in 2 and 3, a DMSO molecule is S-bonded to the metal centre. For 3, all data indicate a square-planar geometry formed by a 9-N bonded caffeine, two trans chloride anions and a DMSO. The three complexes undergo changes in solution upon incubation for 24 h; 1 and 2 release curcumin while 3 isomerizes from trans to cis configuration. The DNA-binding and cytotoxic properties of 1-3 were evaluated in vitro. Despite their structural similarity, curcuminate-containing 1 and 2 exhibit distinct DNA interactions. While 1 appears to intercalate between nucleobase pairs, inducing the oxidative degradation of the biomolecule, 2 behaves as a groove binder, by means of electrostatic forces. Caffeine-containing 3 exhibits a behaviour that is comparable to that of 2. Complexes 1 and 2 showed moderate to high cytotoxicity and selectivity against several cancer cell lines, while 3 is inactive. Compounds 1 and 2 can be further activated by visible-light irradiation.

Caffeine Sensitizes U87-MG Human Glioblastoma Cells to Temozolomide through Mitotic Catastrophe by Impeding G2 Arrest

Temozolomide (TMZ) is the first-line chemotherapeutic agent in the treatment of glioblastoma multiforme (GBM). Despite its cytotoxic effect, TMZ also induces cell cycle arrest that may lead to the development of chemoresistance and eventual tumor recurrence. Caffeine, a widely consumed neurostimulant, shows anticancer activities and is reported to work synergistically with cisplatin and camptothecin. The present study aimed to investigate the effects and the mechanisms of action of caffeine used in combination with TMZ in U87-MG GBM cells. As anticipated, TMZ caused DNA damage mediated by the ATM/p53/p21 signaling pathway and induced significant G2 delay. Concurrent treatment with caffeine repressed proliferation and lowered clonogenic capacity on MTT and colony formation assays, respectively. Mechanistic study showed that coadministration of caffeine and TMZ suppressed the phosphorylation of ATM and p53 and downregulated p21 expression, thus releasing DNA-damaged cells from G2 arrest into premature mitosis. Cell cycle analysis demonstrated that the proportion of cells arrested in G2 phase decreased when caffeine was administered together with TMZ; at the same time, the amount of cells with micronucleation and multipolar spindle poles increased, indicative of enhanced mitotic cell death. Pretreatment of cells with caffeine further enhanced mitotic catastrophe development in combined treatment and sensitized cells to apoptosis when followed by TMZ alone. In conclusion, our study demonstrated that caffeine enhanced the efficacy of TMZ through mitotic cell death by impeding ATM/p53/p21-mediated G2 arrest.

Overcoming chemoresistance in pancreatic cancer cells: role of the bitter taste receptor T2R10

Bitter taste receptors (T2Rs) are G-protein coupled transmembrane proteins initially identified in the gustatory system as sensors for the taste of bitter. Recent evidence on expression of these receptors outside gustatory tissues suggested alternative functions, and there is growing interest of their potential role in cancer biology. In this study, we report for the first time, expression and functionality of the bitter receptor family member T2R10 in both human pancreatic ductal adenocarcinoma (PDAC) tissue and PDAC derived cell lines. Caffeine, a known ligand for T2R10, rendered the tumor cells more susceptible to two standard chemotherapeutics, Gemcitabine and 5-Fluoruracil. Knocking down T2R10 in the cell line BxPC-3 reduced the caffeine-induced effect. As possible underlying mechanism, we found that caffeine via triggering T2R10 inhibited Akt phosphorylation and subsequently downregulated expression of ABCG2, the so-called multi-drug resistance protein that participates in rendering cells resistant to a variety of chemotherapeutics. In conclusion, T2R10 is expressed in pancreatic cancer and it downmodulates the chemoresistance of the tumor cells.

Caffeine inhibits hepatitis C virus replication in vitro

Hepatitis C is considered the major cause of cirrhosis and hepatocellular carcinoma. Conventional treatment is not effective against some hepatitis C virus (HCV) genotypes; therefore, new treatments are needed. Coffee and, more recently, caffeine, have been found to have a beneficial effect in several disorders of the liver, including those manifesting abnormal liver biochemistry, cirrhosis and hepatocellular carcinoma. Caffeine acts directly by delaying fibrosis, thereby improving the function of liver cellular pathways and interfering with pathways used by the HCV replication cycle. In the current study, the direct relationship between caffeine and viral replication was evaluated. The Huh-7.5 cell line was used for transient infections with FL-J6/JFH-5'C19Rluc2AUbi and to establish a cell line stably expressing SGR-Feo JFH-1. Caffeine efficiently inhibited HCV replication in a dose-dependent manner at non-cytotoxic concentrations and demonstrated an IC50 value of 0.7263 mM after 48 h of incubation. These data demonstrate that caffeine may be an important new agent for anti-HCV therapies due to its efficient inhibition of HCV replication at non-toxic concentrations.

Caffeine induces cytoskeletal changes and cell death in H1299 cells

Caffeine is the most common natural neuroactive substance around the world. The exact mechanism of the anticancer effects of caffeine is not clear, especially in the contexts of the cytoskeletal changes. It is known that caffeine exerts an effect on cell cycle, cell proliferation, radiosensivity of cells, and also induces cell death. The aim of the study was to determine the effect of 10 and 20 mM L−1 caffeine on the major cytoskeletal proteins in non-small lung cancer cell line H1299. Caffeine treatment induced abnormalities in morphology and ultrastructure of cells. Moreover, the fluorescence studies showed changes in organization of vimentin, β-tubulin, lamin A/C and F-actin, which were attributed to the induction of cell death. The results also demonstrated that caffeine induced formation of two cell populations: giant, mono- or multinucleated cells, with the phenotype of mitotic catastrophe and shrunken cells with condensation of chromatin, typical of apoptosis. This study for the first time shows the effect of caffeine on the cytoskeleton of H1299 cell line. In conclusion, a high-dose caffeine treatment induces apoptotic cell death and makes it a powerful anticancer agent that should be considered for the treatment of non-small cell lung cancer.

Caffeine and the analog CGS 15943 inhibit cancer cell growth by targeting the phosphoinositide 3-kinase/Akt pathway

Caffeine is a naturally occurring methylxanthine that acts as a non-selective adenosine receptor antagonist. Epidemiological studies demonstrated habitual coffee drinking to be significantly associated with liver cancer survival. We aimed to investigate the effects of caffeine and its analog CGS 15943 on hepatocellular carcinoma (HCC) and pancreatic cancer adenocarcinoma (PDAC). We demonstrate that caffeine and CGS 15943 block proliferation in HCC and PDAC cell lines by inhibiting the PI3K/Akt pathway. Importantly a kinase profiling assay reveals that CGS 15943 targets specifically the catalytic subunit of the class IB PI3K isoform (p110γ). These data give mechanistic insight into the action of caffeine and its analogs and they identify these compounds as promising lead compounds to develop drugs that can specifically target this PI3K isoform whose key role in cancer progression is emerging.

Spectral analysis of naturally occurring methylxanthines (theophylline, theobromine and caffeine) binding with DNA

Nucleic acids exist in a dynamic equilibrium with a number of molecules that constantly interact with them and regulate the cellular activities. The inherent nature of the structure and conformational integrity of these macromolecules can lead to altered biological activity through proper targeting of nucleic acids binding ligands or drug molecules. We studied the interaction of naturally occurring methylxanthines such as theophylline, theobromine and caffeine with DNA, using UV absorption and Fourier transform infrared (FTIR) spectroscopic methods, and especially monitored their binding affinity in the presence of Mg(2+) and during helix-coil transitions of DNA by temperature (T(m)) or pH melting profiles. The study indicates that all these molecules effectively bind to DNA in a dose dependent manner. The overall binding constants of DNA-theophylline = 3.5×10(3) M(-1), DNA-theobromine = 1.1×10(3) M(-1), and DNA-Caffeine = 3.8×10(3) M(-1). On the other hand T(m)/pH melting profiles showed 24-35% of enhanced binding activity of methylxanthines during helix-coil transitions of DNA rather than to its native double helical structure. The FTIR analysis divulged that theophylline, theobromine and caffeine interact with all the base pairs of DNA (A-T; G-C) and phosphate group through hydrogen bond (H-bond) interaction. In the presence of Mg(2+), methylxanthines altered the structure of DNA from B to A-family. However, the B-family structure of DNA remained unaltered in DNA-methylxanthines complexes or in the absence of Mg(2+). The spectral analyses indicated the order of binding affinity as "caffeine≥theophylline>theobromine" to the native double helical DNA, and "theophylline≥theobromine>caffeine to the denatured form of DNA and in the presence of divalent metal ions.