Specific A3 adenosine receptor (A3AR) agonist, 2‑chloro‑N6‑(3‑iodobenzyl)‑5'‑N‑methylcarboxamidoadenosine (2‑Cl‑IB‑MECA), demonstrates anti‑proliferative effects on various types of tumor. In the present study, the cytotoxicity of 2‑Cl‑IB‑MECA was analyzed in a panel of tumor and non‑tumor cell lines and its anticancer mechanisms in JoPaca‑1 pancreatic and Hep‑3B hepatocellular carcinoma cell lines were also investigated. Initially, decreased tumor cell proliferation, cell accumulation in the G1 phase and inhibition of DNA and RNA synthesis was found. Furthermore, western blot analysis showed decreased protein expression level of β‑catenin, patched1 (Ptch1) and glioma‑associated oncogene homolog zinc finger protein 1 (Gli1), which are components of the Wnt/β‑catenin and Sonic hedgehog/Ptch/Gli transduction pathways. In concordance with these findings, the protein expression levels of cyclin D1 and c‑Myc were reduced. Using a luciferase assay, it was revealed for the first time a decrease in β‑catenin transcriptional activity, as an early event following 2‑Cl‑IB‑MECA treatment. In addition, the protein expression levels of multidrug resistance‑associated protein 1 and P‑glycoprotein (P‑gp) were reduced and the P‑gp xenobiotic efflux function was also reduced. Next, the enhancing effects of 2‑Cl‑IB‑MECA on the cytotoxicity of conventional chemotherapy was investigated. It was found that 2‑Cl‑IB‑MECA enhanced carboplatin and doxorubicin cytotoxic effects in the JoPaca‑1 and Hep‑3B cell lines, and a greater synergy was found in the highly tumorigenic JoPaca‑1 cell line. This provides a novel in vitro rationale for the utilization of 2‑Cl‑IB‑MECA in combination with chemotherapeutic agents, not only for hepatocellular carcinoma, but also for pancreatic cancer. Other currently used conventional chemotherapeutics, fluorouracil and gemcitabine, showed synergy only when combined with high doses of 2‑Cl‑IB‑MECA. Notably, experiments with A3AR‑specific antagonist, N‑[9‑Chloro‑2‑(2‑furanyl)(1,2,4)‑triazolo(1,5‑c)quinazolin‑5‑yl]benzene acetamide, revealed that 2‑Cl‑IB‑MECA had antitumor effects via both A3AR‑dependent and ‑independent pathways. In conclusion, the present study identified novel antitumor mechanisms of 2‑Cl‑IB‑MECA in pancreatic and hepatocellular carcinoma in vitro that further underscores the importance of A3AR agonists in cancer therapy.

• Klíčová slova
• 2‑Cl‑IB‑MECA, adenosine A3 receptor, chemosensitivity, hepatocellular carcinoma, multidrug resistance, pancreatic carcinoma,
• MeSH
• adenosin analogy a deriváty   MeSH
• buněčné linie MeSH
• léková rezistence MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádory jater * farmakoterapie   MeSH
• nádory slinivky břišní * genetika   MeSH
• proliferace buněk MeSH
• protein Gli1 genetika   metabolismus   MeSH
• proteiny hedgehog MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 2-chloro-N(6)-(3-iodobenzyl)adenosine-5'-N-methyluronamide MeSH Prohlížeč
• adenosin MeSH
• protein Gli1 MeSH
• proteiny hedgehog MeSH

A key objective in immuno-oncology is to reactivate the dormant immune system and increase tumour immunogenicity. Adenosine is an omnipresent purine that is formed in response to stress stimuli in order to restore physiological balance, mainly via anti-inflammatory, tissue-protective, and anti-nociceptive mechanisms. Adenosine overproduction occurs in all stages of tumorigenesis, from the initial inflammation/local tissue damage to the precancerous niche and the developed tumour, making the adenosinergic pathway an attractive but challenging therapeutic target. Many current efforts in immuno-oncology are focused on restoring immunosurveillance, largely by blocking adenosine-producing enzymes in the tumour microenvironment (TME) and adenosine receptors on immune cells either alone or combined with chemotherapy and/or immunotherapy. However, the effects of adenosinergic immunotherapy are not restricted to immune cells; other cells in the TME including cancer and stromal cells are also affected. Here we summarise recent advancements in the understanding of the tumour adenosinergic system and highlight the impact of current and prospective immunomodulatory therapies on other cell types within the TME, focusing on adenosine receptors in tumour cells. In addition, we evaluate the structure- and context-related limitations of targeting this pathway and highlight avenues that could possibly be exploited in future adenosinergic therapies.

• Klíčová slova
• adenosine, adenosine receptors, adenosinergic therapy, adverse effects, cancer, immuno-oncology, immunosurveillance, tumour microenvironment,
• MeSH
• adenosin biosyntéza   genetika   imunologie   terapeutické užití   MeSH
• cílená molekulární terapie * MeSH
• imunoterapie trendy   MeSH
• karcinogeneze účinky léků   imunologie   MeSH
• lidé MeSH
• nádorové mikroprostředí účinky léků   imunologie   MeSH
• nádory genetika   imunologie   terapie   MeSH
• purinergní receptory P1 imunologie   terapeutické užití   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• adenosin MeSH
• purinergní receptory P1 MeSH

The synthetic curcumin analogue, 3,5-bis[(2-fluorophenyl)methylene]-4-piperidinone (EF-24), suppresses NF-κB activity and exhibits antiproliferative effects against a variety of cancer cells in vitro. Recently, it was reported that EF-24-induced apoptosis was mediated by a redox-dependent mechanism. Here, we studied the effects of N-acetylcysteine (NAC) on EF-24-induced cell death. We also addressed the question of whether the main drug transporters, ABCB1 and ABCG2, affect the cytotoxic of EF-24. We observed that EF-24 induced cell death with apoptotic hallmarks in human leukemia K562 cells. Importantly, the loss of cell viability was preceded by production of reactive oxygen species (ROS), and by a decrease of reduced glutathione (GSH). However, neither ROS production nor the decrease in GSH predominantly contributed to the EF-24-induced cell death. We found that EF-24 formed an adduct with GSH, which is likely the mechanism contributing to the decrease of GSH. Although NAC abrogated ROS production, decreased GSH and prevented cell death, its protective effect was mainly due to a rapid conversion of intra- and extra-cellular EF-24 into the EF-24-NAC adduct without cytotoxic effects. Furthermore, we found that neither overexpression of ABCB1 nor ABCG2 reduced the antiproliferative effects of EF-24. In conclusion, a redox-dependent-mediated mechanism only marginally contributes to the EF-24-induced apoptosis in K562 cells. The main mechanism of NAC protection against EF-24-induced apoptosis is conversion of cytotoxic EF-24 into the noncytotoxic EF-24-NAC adduct. Neither ABCB1 nor ABCG2 mediated resistance to EF-24.

• Klíčová slova
• EF-24-GSH adduct, EF-24-NAC adduct, K562 cells, NF-κB, Nrf2,
• MeSH
• ABC transportér z rodiny G, člen 2 genetika   metabolismus   MeSH
• acetylcystein metabolismus   MeSH
• apoptóza účinky léků   MeSH
• benzylidenové deriváty farmakologie   MeSH
• glutathion metabolismus   MeSH
• leukemie metabolismus   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádorové proteiny genetika   metabolismus   MeSH
• oxidační stres * MeSH
• P-glykoproteiny genetika   metabolismus   MeSH
• piperidony farmakologie   MeSH
• protinádorové látky farmakologie   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 3,5-bis(2-fluorobenzylidene)piperidin-4-one MeSH Prohlížeč
• ABC transportér z rodiny G, člen 2 MeSH
• ABCB1 protein, human MeSH Prohlížeč
• ABCG2 protein, human MeSH Prohlížeč
• acetylcystein MeSH
• benzylidenové deriváty MeSH
• glutathion MeSH
• nádorové proteiny MeSH
• P-glykoproteiny MeSH
• piperidony MeSH
• protinádorové látky MeSH
• reaktivní formy kyslíku MeSH

The question as to whether A3 adenosine receptor (A3AR) agonists, N (6)-(3-iodobenzyl)-adenosine-5'-N- methyluronamide (IB-MECA) and 2-chloro-N (6)-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (Cl-IB-MECA), could exert cytotoxic effects at high concentrations with or without the involvement of A3AR has been a controversial issue for a long time. The initial findings suggesting that A3AR plays a crucial role in the induction of cell death upon treatment with micromolar concentrations of IB-MECA or Cl-IB-MECA were revised, however, the direct and unequivocal evidence is still missing. Therefore, the sensitivity of Chinese hamster ovary (CHO) cells transfected with human recombinant A3AR (A3-CHO) and their counter partner wild-type CHO cells, which do not express any of adenosine receptors, to micromolar concentrations of IB-MECA and Cl-IB-MECA was studied. We observed that IB-MECA and Cl-IB-MECA exhibited a strong inhibitory effect on cell proliferation due to the blockage of cell cycle progression at G1/S and G2/M transitions in both A3-CHO and CHO cells. Further analysis revealed that IB-MECA and Cl-IB-MECA attenuated the Erk1/2 signalling irrespectively to A3AR expression. In addition, Cl-IB-MECA induced massive cell death mainly with hallmarks of a necrosis in both cell lines. In contrast, IB-MECA affected cell viability only slightly independently of A3AR expression. IB-MECA induced cell death that exhibited apoptotic hallmarks. In general, the sensitivity of A3-CHO cells to micromolar concentrations of IB-MECA and Cl-IB-MECA was somewhat, but not significantly, higher than that observed in the CHO cells. These results strongly suggest that IB-MECA and Cl-IB-MECA exert cytotoxic effects at micromolar concentrations independently of A3AR expression.

• MeSH
• adenosin analogy a deriváty   farmakologie   MeSH
• agonisté adenosinového receptoru A3 farmakologie   MeSH
• CHO buňky MeSH
• Cricetulus MeSH
• cytotoxiny farmakologie   MeSH
• kontrolní body buněčného cyklu účinky léků   MeSH
• lidé MeSH
• mitogenem aktivovaná proteinkinasa 1 antagonisté a inhibitory   genetika   metabolismus   MeSH
• mitogenem aktivovaná proteinkinasa 3 antagonisté a inhibitory   genetika   metabolismus   MeSH
• proliferace buněk účinky léků   MeSH
• protoonkogenní proteiny c-akt genetika   metabolismus   MeSH
• receptor adenosinový A3 genetika   metabolismus   MeSH
• regulace genové exprese MeSH
• signální transdukce účinky léků   MeSH
• transfekce MeSH
• viabilita buněk účinky léků   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 2-chloro-N(6)-(3-iodobenzyl)adenosine-5'-N-methyluronamide MeSH Prohlížeč
• adenosin MeSH
• agonisté adenosinového receptoru A3 MeSH
• cytotoxiny MeSH
• MAPK1 protein, human MeSH Prohlížeč
• mitogenem aktivovaná proteinkinasa 1 MeSH
• mitogenem aktivovaná proteinkinasa 3 MeSH
• N(6)-(3-iodobenzyl)-5'-N-methylcarboxamidoadenosine MeSH Prohlížeč
• protoonkogenní proteiny c-akt MeSH
• receptor adenosinový A3 MeSH