RESUMEN
Trichomonas vaginalis, the causative agent of trichomoniasis, is a prevalent anaerobic protozoan parasite responsible for the most common nonviral sexually transmitted infection globally. While metronidazole and its derivatives are approved drugs for this infection, rising resistance necessitates the exploration of new antiparasitic therapies. Protein posttranslational modifications (PTMs) play crucial roles in cellular processes, and among them, hypusination, involving eukaryotic translation factor 5A (eIF5A), has profound implications. Despite extensive studies in various organisms, the role of hypusination in T. vaginalis and its potential impact on parasite biology and pathogenicity remain poorly understood. This study aims to unravel the structural basis of the hypusination pathway in T. vaginalis using X-ray crystallography and cryo-electron microscopy. The results reveal high structural homology between T. vaginalis and human orthologs, providing insights into the molecular architecture of eIF5A and deoxyhypusine synthase (DHS) and their interaction. Contrary to previous suggestions of bifunctionality, our analyses indicate that the putative hydroxylation site in tvDHS is nonfunctional, and biochemical assays demonstrate exclusive deoxyhypusination capability. These findings challenge the notion of tvDHS functioning as both deoxyhypusine synthase and hydroxylase. The study enhances understanding of the hypusination pathway in T. vaginalis, shedding light on its functional relevance and potential as a drug target, and contributing to the development of novel therapeutic strategies against trichomoniasis.
RESUMEN
Glioblastoma multiforme (GBM) recurrences after temozolomide (TMZ) treatment result from the expansion of drug-resistant and potentially invasive GBM cells. This process is facilitated by O6-Methylguanine-DNA Methyltransferase (MGMT), which counteracts alkylating TMZ activity. We traced the expansion of invasive cell lineages under persistent chemotherapeutic stress in MGMTlow (U87) and MGMThigh (T98G) GBM populations to look into the mechanisms of TMZ-induced microevolution of GBM invasiveness. TMZ treatment induced short-term, pro-invasive phenotypic shifts of U87 cells, in the absence of Snail-1 activation. They were illustrated by a transient induction of their motility and followed by the hypertrophy and the signs of senescence in scarce U87 sub-populations that survived long-term TMZ stress. In turn, MGMThigh T98G cells reacted to the long-term TMZ treatment with the permanent induction of invasiveness. Ectopic Snail-1 down-regulation attenuated this effect, whereas its up-regulation augmented T98G invasiveness. MGMTlow and MGMThigh cells both reacted to the long-term TMZ stress with the induction of Cx43 expression. However, only in MGMThigh T98G populations, Cx43 was directly involved in the induction of invasiveness, as manifested by the induction of T98G invasiveness after ectopic Cx43 up-regulation and by the opposite effect after Cx43 down-regulation. Collectively, Snail-1/Cx43-dependent signaling participates in the long-term TMZ-induced microevolution of the invasive GBM front. High MGMT activity remains a prerequisite for this process, even though MGMT-related GBM chemoresistance is not necessary for its initiation.
Asunto(s)
Antineoplásicos Alquilantes/farmacología , Movimiento Celular/efectos de los fármacos , Metilasas de Modificación del ADN/metabolismo , Enzimas Reparadoras del ADN/metabolismo , Glioblastoma/metabolismo , Temozolomida/farmacología , Proteínas Supresoras de Tumor/metabolismo , Animales , Línea Celular Tumoral , Conexina 43/metabolismo , Metilasas de Modificación del ADN/genética , Enzimas Reparadoras del ADN/genética , Humanos , Fenotipo , Ratas , Factores de Transcripción de la Familia Snail/metabolismo , Proteínas Supresoras de Tumor/genéticaRESUMEN
Bisphenol A (BPA) is commonly present in plastics used for food storage and preservation. The release of BPA from these products results in a permanent human exposition to BPA; however, the quality and quantity of BPA adverse effects remain a matter of controversy. The common presence of BPA in the human environment and the controversies concerning the relations of human exposition to BPA and cancer incidence justify the research on the interactions between BPA and pro-metastatic signaling in cancer cells. Here, we describe a novel BPA-reactive signaling axis that induces the epithelial-mesenchymal transition (EMT) in lung adenocarcinoma A549 cells. BPA exerted negligible effects on their properties in a wide range of concentrations (10â¯nM - 100â¯nM), whereas it considerably induced A549 invasiveness at high concentrations (10⯵M). The BPA-induced EMT was illustrated by morphologic changes, E/N-cadherin switch and vimentin/Snail-1/connexin(Cx)43 up-regulation in A549 populations. It was followed by enhancement of A549 drug-resistance. Corresponding effects of BPA were observed in prostate cancer cell populations. Concomitantly, we observed increased levels and perinuclear accumulation of estrogen-related receptor gamma (ERRγ) in BPA-treated cells, its interactions with Cx43/Snail-1, and the corresponding effects of phenol red on A549 cells. Collectively, these data identify a novel, pro-metastatic Snail-1/Cx43/ERRγ signaling pathway. Its reactivity to BPA underlies the induction of cancer cells' invasiveness in the presence of high BPA concentrations in vitro. Thus, the chronic exposition of cancer cells to extrinsic and intrinsic BPA should be considered as a potential obstacle in a cancer therapy.
Asunto(s)
Compuestos de Bencidrilo/toxicidad , Movimiento Celular/efectos de los fármacos , Conexina 43/metabolismo , Transición Epitelial-Mesenquimal/efectos de los fármacos , Estrógenos/toxicidad , Fenoles/toxicidad , Receptores de Estrógenos/metabolismo , Factores de Transcripción de la Familia Snail/metabolismo , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Humanos , FenolsulfonftaleínaRESUMEN
Thuja occidentalis L. is indigenous for Northern America and commonly cultivated in Europe. Raw materials obtained from this tree are widely applied in the ethnomedicine and phytotherapy of numerous ailments, incl. scurvy, cystitis, rheumatism and cancer. Despite wide medicinal applications of Thuja occidentalis, still little is known on its therapeutic potential in tumor treatment. α-thujone is the main component of Thuja occidentalis essential oil, which has been suggested to possess anti-tumor activities. This monoterpene easily penetrates the blood-brain barrier. Therefore, we examined its effects on the malignancy of glioblastoma multiforme (GBM) cells, with the special emphasis on the mechanisms of its effect on cell viability and invasiveness. α-thujone exerted the attenuating effect on the viability and proliferation of GBM cells when administered at the concentrations between 100 and 500⯵g/ml (660⯵M - 3.2â¯mM). This effect was correlated with the induction of apoptosis in GBM cell populations and with considerable inhibition of GBM cells motility. Mechanistic analyses demonstrated the induction of oxidative stress and autophagy in α-thujone-treated tumor cells, whereas normal astrocytes displayed considerably lower sensitivity to α-thujone. Our observations demonstrate that α-thujone exerts pro-apoptotic and anti-invasive effects on GBM cells. They confirm the potential of α-thujone for the treatment of glioblastoma multiforme.