Association of SLC12A1 and GLUR4 Ion Transporters with Neoadjuvant Chemoresistance in Luminal Locally Advanced Breast Cancer.

Chemoresistance to standard neoadjuvant treatment commonly occurs in locally advanced breast cancer, particularly in the luminal subtype, which is hormone receptor-positive and represents the most common subtype of breast cancer associated with the worst outcomes. Identifying the genes associated with chemoresistance is crucial for understanding the underlying mechanisms and discovering effective treatments. In this study, we aimed to identify genes linked to neoadjuvant chemotherapy resistance in 62 retrospectively included patients with luminal breast cancer. Whole RNA sequencing of 12 patient biopsies revealed 269 differentially expressed genes in chemoresistant patients. We further validated eight highly correlated genes associated with resistance. Among these, solute carrier family 12 member 1 (SLC12A1) and glutamate ionotropic AMPA type subunit 4 (GRIA4), both implicated in ion transport, showed the strongest association with chemoresistance. Notably, SLC12A1 expression was downregulated, while protein levels of glutamate receptor 4 (GLUR4), encoded by GRIA4, were elevated in patients with a worse prognosis. Our results suggest a potential link between SLC12A1 gene expression and GLUR4 protein levels with chemoresistance in luminal breast cancer. In particular, GLUR4 protein could serve as a potential target for drug intervention to overcome chemoresistance.

Mutational Landscape of Bladder Cancer in Mexican Patients: KMT2D Mutations and chr11q15.5 Amplifications Are Associated with Muscle Invasion.

Bladder cancer (BC) is the most common neoplasm of the urinary tract, which originates in the epithelium that covers the inner surface of the bladder. The molecular BC profile has led to the development of different classifications of non-muscle invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC). However, the genomic BC landscape profile of the Mexican population, including NMIBC and MIBC, is unknown. In this study, we aimed to identify somatic single nucleotide variants (SNVs) and copy number variations (CNVs) in Mexican patients with BC and their associations with clinical and pathological characteristics. We retrospectively evaluated 37 patients treated between 2012 and 2021 at the National Cancer Institute-Mexico (INCan). DNA samples were obtained from paraffin-embedded tumor tissues and exome sequenced. Strelka2 and Lancet packages were used to identify SNVs and insertions or deletions. FACETS was used to determine CNVs. We found a high frequency of mutations in TP53 and KMT2D, gains in 11q15.5 and 19p13.11-q12, and losses in 7q11.23. STAG2 mutations and 1q11.23 deletions were also associated with NMIBC and low histologic grade.

DNA Methyltransferases: From Evolution to Clinical Applications.

DNA methylation is an epigenetic mark that living beings have used in different environments. The MTases family catalyzes DNA methylation. This process is conserved from archaea to eukaryotes, from fertilization to every stage of development, and from the early stages of cancer to metastasis. The family of DNMTs has been classified into DNMT1, DNMT2, and DNMT3. Each DNMT has been duplicated or deleted, having consequences on DNMT structure and cellular function, resulting in a conserved evolutionary reaction of DNA methylation. DNMTs are conserved in the five kingdoms of life: bacteria, protists, fungi, plants, and animals. The importance of DNMTs in whether methylate or not has a historical adaptation that in mammals has been discovered in complex regulatory mechanisms to develop another padlock to genomic insurance stability. The regulatory mechanisms that control DNMTs expression are involved in a diversity of cell phenotypes and are associated with pathologies transcription deregulation. This work focused on DNA methyltransferases, their biology, functions, and new inhibitory mechanisms reported. We also discuss different approaches to inhibit DNMTs, the use of non-coding RNAs and nucleoside chemical compounds in recent studies, and their importance in biological, clinical, and industry research.

The Roles of Histone Post-Translational Modifications in the Formation and Function of a Mitotic Chromosome.

During mitosis, many cellular structures are organized to segregate the replicated genome to the daughter cells. Chromatin is condensed to shape a mitotic chromosome. A multiprotein complex known as kinetochore is organized on a specific region of each chromosome, the centromere, which is defined by the presence of a histone H3 variant called CENP-A. The cytoskeleton is re-arranged to give rise to the mitotic spindle that binds to kinetochores and leads to the movement of chromosomes. How chromatin regulates different activities during mitosis is not well known. The role of histone post-translational modifications (HPTMs) in mitosis has been recently revealed. Specific HPTMs participate in local compaction during chromosome condensation. On the other hand, HPTMs are involved in CENP-A incorporation in the centromere region, an essential activity to maintain centromere identity. HPTMs also participate in the formation of regulatory protein complexes, such as the chromosomal passenger complex (CPC) and the spindle assembly checkpoint (SAC). Finally, we discuss how HPTMs can be modified by environmental factors and the possible consequences on chromosome segregation and genome stability.

Expression of DNA Methyltransferase 3B Isoforms Is Associated with DNA Satellite 2 Hypomethylation and Clinical Prognosis in Advanced High-Grade Serous Ovarian Carcinoma.

Alterations in DNA methylation are critical for the carcinogenesis of ovarian tumors, especially ovarian carcinoma (OC). DNMT3B, a de novo DNA methyltransferase (DNMT), encodes for fifteen spliced protein products or isoforms. DNMT3B isoforms lack exons for the catalytic domain, with functional consequences on catalytic activity. Abnormal expression of DNMT3B isoforms is frequently observed in several types of cancer, such as breast, lung, kidney, gastric, liver, skin, leukemia, and sarcoma. However, the expression patterns and consequences of DNMT3B isoforms in OC are unknown. In this study, we analyzed each DNMT and DNMT3B isoforms expression by qPCR in 63 OC samples and their association with disease-free survival (DFS), overall survival (OS), and tumor progression. We included OC patients with the main histological subtypes of EOC and patients in all the disease stages and found that DNMTs were overexpressed in advanced stages (p-value < 0.05) and high-grade OC (p-value < 0.05). Remarkably, we found DNMT3B1 overexpression in advanced stages (p-value = 0.0251) and high-grade serous ovarian carcinoma (HGSOC) (p-value = 0.0313), and DNMT3B3 was overexpressed in advanced stages (p-value = 0.0098) and high-grade (p-value = 0.0004) serous ovarian carcinoma (SOC). Finally, we observed that overexpression of DNMT3B isoforms was associated with poor prognosis in OC and SOC. DNMT3B3 was also associated with FDS (p-value = 0.017) and OS (p-value = 0.038) in SOC patients. In addition, the ovarian carcinoma cell lines OVCAR3 and SKOV3 also overexpress DNMT3B3. Interestingly, exogenous overexpression of DNMT3B3 in OVCAR3 causes demethylation of satellite 2 sequences in the pericentromeric region. In summary, our results suggest that DNMT3B3 expression is altered in OC.

The Role of microRNAs in the Gonocyte Theory as Target of Malignancy: Looking for Potential Diagnostic Biomarkers.

Some pediatric patients with cryptorchidism preserve cells with gonocyte characteristics beyond their differentiation period, which could support the theory of the gonocyte as a target for malignancy in the development of testicular neoplasia. One of the key molecules in gonocyte malignancy is represented by microRNAs (miRNAs). The goal of this review is to give an overview of miRNAs, a class of small non-coding RNAs that participate in the regulation of gene expression. We also aim to review the crucial role of several miRNAs that have been further described in the regulation of gonocyte differentiation to spermatogonia, which, when transformed, could give rise to germ cell neoplasia in situ, a precursor lesion to testicular germ cell tumors. Finally, the potential use of miRNAs as diagnostic and prognostic biomarkers in testicular neoplasia is addressed, due to their specificity and sensitivity compared to conventional markers, as well as their applications in therapeutics.

Long-term PM2.5 exposure before diagnosis is associated with worse outcome in breast cancer.

PURPOSE: Increasingly epidemiological evidence supports that environmental factors are associated with breast cancer (BC) outcomes after a BC diagnosis. Although evidence suggests that air pollution exposure is associated with higher mortality in women with BC, studies investigating potential mechanisms have been lacking. METHODS: We evaluated women with BC (N = 151) attended at the National Cancer Institute-Mexico from 2012 to 2015. We calculated 1-year average exposures to particulate matter < 2.5 µm (PM2.5) at home address before diagnosis. We used linear and logistic regression models to determine the associations between PM2.5 exposure and BC aggressiveness (tumor size, molecular phenotype). RESULTS: Average annual PM2.5 exposure of this population was 23.0 µg/m3 [standard deviation (SD)]: 1.90 µg/m3]. PM2.5 levels were positively correlated with tumor size at diagnosis (r = 0.22; p = 0.007). Multivariable linear models had a similar inference [risk ratio (RR): 1.32; 95% confidence interval (95% CI): 1.04, 1.674]. We did not observe differences in this association by age or menopause status. Further, women with triple-negative BC (TNBC) had significantly higher PM2.5 levels compared with other phenotypes (p = 0.015). Multivariable-adjusted logistic regression models assessing the association between PM2.5 and tumor size had a similar inference (RR 1.41; 95% CI 1.05, 1.89) overall for all ages and also for women who were ≤ 50 years old at diagnosis (RR 1.63; 95% CI 1.036, 2.57). CONCLUSIONS: Our findings suggest a significant association between long-term PM2.5 exposure and BC aggressiveness based on tumor size and phenotype, as well as a worse outcome.

Prognostic Significance of the MAD1L1 1673 G: A Polymorphism in Ovarian Adenocarcinomas.

BACKGROUND: Ovarian cancer is the most lethal gynecologic cancer. Although most patients respond adequately to the first-line therapy, up to 85% experience a recurrence of disease, which carries a poor prognosis. Mitotic arrest deficiency 1 is a protein that helps in the assembly of the mitotic spindle assembly checkpoint by preventing anaphase until all chromatids are properly aligned. A single-nucleotide polymorphism in the MAD1L1 gene is prevalent in patients with advanced epithelial ovarian cancer and alters the way in which it responds to chemotherapy. OBJECTIVE: The objective of the study was to study the relationship between the rs1801368 polymorphism of MAD1L1 and prognosis of ovarian adenocarcinoma. METHODS: A total of 118 patients in whom the MAD1L1 gene was sequenced were analyzed using descriptive and comparative statistics. RESULTS: Patients carrying the wild-type genotype had a higher distribution of early-stage disease. Having a MAD1L1 polymorphic allele increased the risk of being non-sensitive to chemotherapy. The median disease-free survival for patients with the wild-type MAD1L1 was 46.93 months, compared to 10.4 months for patients with at least one polymorphic allele. CONCLUSIONS: The rs1801368 polymorphism of MAD1L1 gene worsens prognosis in patients with ovarian adenocarcinoma. Traditional therapy for ovarian cancer might not be optimal in patients carrying this polymorphism.

Prognostic Significance of the MAD1L1 1673 G: A Polymorphism in Ovarian Adenocarcinomas.

BACKGROUND: Ovarian cancer is the most lethal gynecologic cancer. Although most patients respond adequately to the first-line therapy, up to 85% experience a recurrence of disease, which carries a poor prognosis. Mitotic arrest deficiency 1 is a protein that helps in the assembly of the mitotic spindle assembly checkpoint by preventing anaphase until all chromatids are properly aligned. A single-nucleotide polymorphism in the MAD1L1 gene is prevalent in patients with advanced epithelial ovarian cancer and alters the way in which it responds to chemotherapy. OBJECTIVE: The objective of the study was to study the relationship between the rs1801368 polymorphism of MAD1L1 and prognosis of ovarian adenocarcinoma. METHODS: A total of 118 patients in whom the MAD1L1 gene was sequenced were analyzed using descriptive and comparative statistics. RESULTS: Patients carrying the wild-type genotype had a higher distribution of early-stage disease. Having a MAD1L1 polymorphic allele increased the risk of being non-sensitive to chemotherapy. The median disease-free survival for patients with the wild-type MAD1L1 was 46.93 months, compared to 10.4 months for patients with at least one polymorphic allele. CONCLUSIONS: The rs1801368 polymorphism of MAD1L1 gene worsens prognosis in patients with ovarian adenocarcinoma. Traditional therapy for ovarian cancer might not be optimal in patients carrying this polymorphism.

Prevalence of germline mutations in the TP53 gene in patients with early-onset breast cancer in the Mexican population.

BACKGROUND: Heterozygous germline TP53 gene mutations result in Li-Fraumeni Syndrome (LFS). Breast cancer (BC) is the most frequent tumor in young women with LFS. An important issue related to BC in the Mexican population is the average age at diagnosis, which is approximately 11 years younger than that of patients in the United States (U.S.) and Europe. The aim of this study was to determine the prevalence of germline mutations in TP53 among young Mexican BC patients. METHODS: We searched for germline mutations in the TP53 gene using targeted next-generation sequencing (NGS) in 78 BC patients younger than 45 years old (yo) who tested negative for BRCA1/2 mutations. A group of 509 Mexican women aged 45yo or older without personal or family BC history (parents/grandparents) was used as a control. RESULTS: We identified five patients with pathogenic variants in the TP53 gene, equivalent to 6.4% (5/78). Among patients diagnosed at age 36 or younger, 9.4% (5/55) had pathogenic TP53 mutations. Three of these variants were missense mutations (c.844C > T, c.517G > A, and c.604C > T), and the other two mutations were frameshifts (c.291delC and c.273dupC) and had not been reported previously. We also identified a variant of uncertain clinical significance (VUS), c.672G > A, which causes a putative splice donor site mutation. All patients with TP53 mutations had high-grade and HER2-positive tumors. None of the 509 patients in the healthy control group had mutations in TP53. CONCLUSIONS: Among Mexican BC patients diagnosed at a young age, we identified a high proportion with germline mutations in the TP53 gene. All patients with the TP53 mutations had a family history suggestive of LFS. To establish the clinical significance of the VUS found, additional studies are needed. Pathogenic variants of TP53 may explain a substantial fraction of BC in young women in the Mexican population. Importantly, none of these mutations or other pathological variants in TP53 were found in the healthy control group.

Addition of analysis of KRAS mutation or immunohistochemistry with MUC1 and carcinoembryonic antigen improves the diagnostic performance of fine needle aspiration cytology for the diagnosis of pancreatic carcinoma.

BACKGROUND: Pancreatic adenocarcinoma (PAC) is a health problem because of high lethality, increasing incidence and the absence of an early diagnosis. Biopsy by fine needle aspiration guided by endoscopic ultrasound has allowed obtaining tissue for cytopathological analysis, but there are several problems with their interpretation. We aimed to compare the diagnostic performance of the cytopathological analysis with the addition of either an immunohistochemical (IHC) panel or the KRAS mutation for the diagnosis of PAC. METHODS: We evaluated 62 pancreatic lesions by fine needle aspiration guided by endoscopic ultrasound, applying an IHC panel with mucin (MUC)-1, MUC4, carcinoembryonic antigen (CEA) and p53. All cases also had a KRAS mutation determination. Three cytopathologists blinded to clinical data and the KRAS status reviewed the cytology independently. We calculated diagnostic performances for the cytology alone, cytology+IHC and cytology+KRAS to show the best method to diagnose PAC. RESULTS: From 62 samples, 50 (80.6%) were PAC and 12 benign lesions. The cytopathological analysis correctly interpreted 26 malignant and 12 non-neoplastic cases (sensitivity 52%, specificity 100% and diagnostic accuracy 61.3%). The KRAS mutation was present in 88% of PAC. The cytology+ KRAS mutation increased the sensitivity by 10% and the diagnostic accuracy by 8%. The sensitivity increased by 2% adding either MUC1 or CEA to the cytology, and the diagnostic accuracy by 10 or 18%, respectively. CONCLUSION: The addition of IHC either with CEA or MUC1 improved the diagnostic performance of the cytology alone to diagnose PAC. The cytology + IHC evaluation was superior to the cytology + KRAS mutation to diagnose PAC.

Expression Levels of Human Equilibrative Nucleoside Transporter 1 and Deoxycytidine Kinase Enzyme as Prognostic Factors in Patients with Acute Myeloid Leukemia Treated with Cytarabine.

BACKGROUND: Cytarabine (Ara-C) is the primary drug in different treatment schemas for acute myeloid leukemia (AML) and requires the human equilibrative nucleoside transporter (hENT1) to enter cells. The deoxycytidine kinase (dCK) enzyme limits its activation rate. Therefore, decreased expression levels of these genes may influence the response rate to this drug. METHODS: AML patients without previous treatment were enrolled. The expression of hENT1 and dCK genes was analyzed using RT-PCR. Clinical parameters were registered. All patients received Ara-C + doxorubicin as an induction regimen (7 + 3 schema). Descriptive statistics were used to analyze data. Uni- and multivariate analyses were performed to determine factors that influenced response and survival. RESULTS: Twenty-eight patients were included from January 2011 until December 2012. Median age was 36.5 years. All patients had an adequate performance status (43% with ECOG 1 and 57% with ECOG 2). Cytogenetic risk was considered unfavorable in 54% of the patients. Complete response was achieved in 53.8%. Cox regression analysis showed that a higher hENT1 expression level was the only factor that influenced response and survival. CONCLUSIONS: These results highly suggest that the pharmacogenetic analyses of Ara-C influx may be decisive in AML patients.

Astemizole-based anticancer therapy for hepatocellular carcinoma (HCC), and Eag1 channels as potential early-stage markers of HCC.

Hepatocellular carcinoma (HCC) has very poor prognosis. Astemizole has gained great interest as a potential anticancer drug because it targets several proteins involved in cancer including the Eag1 (ether à-go-go-1) potassium channel that is overexpressed in human HCC. Eag1 channels are regulated by cancer etiological factors and have been proposed as early tumor markers. Here, we found that HepG2 and HuH-7 HCC cells displayed Eag1 messenger RNA (mRNA) and protein expression, determined by real-time RT-PCR and immunochemistry, respectively. Astemizole inhibited human HCC cell proliferation (assessed by metabolic activity assay) and induced apoptosis (studied with flow cytometry) in both cell lines. The subcellular Eag1 protein localization was modified by astemizole in the HepG2 cells. The treatment with astemizole prevented diethylnitrosamine (DEN)-induced rat HCC development in vivo (followed by studying γ-glutamyl transpeptidase (GGT) activity). The Eag1 mRNA and protein levels were increased in most DEN-treated groups but decreased after astemizole treatment. GGT activity was decreased by astemizole. The Eag1 protein was detected in cirrhotic and dysplastic rat livers. Astemizole might have clinical utility for HCC prevention and treatment, and Eag1 channels may be potential early HCC biomarkers. These data provide significant basis to include astemizole in HCC clinical trials.

The HPV16 E6 oncoprotein and UVB irradiation inhibit the tumor suppressor TGFß pathway in the epidermis of the K14E6 transgenic mouse.

High-risk human papillomaviruses (HR-HPVs) are the causative agents of cervical cancer, and they are also associated with a subset of head and neck squamous cell carcinomas. In addition, HPVs have also been postulated in the development of non-melanoma skin cancers (NMSC). In these cancers, the oncogene E6 is best known for its ability to inactivate the tumor suppressor p53 protein. Interestingly, in transgenic mice for HPV16 E6 (K14E6), it was reported that E6 alone induced epithelial hyperplasia and delay in differentiation in skin epidermis independently of p53 inactivation. Transforming growth factor ß (TGFß) is an important regulator of cell growth/differentiation and apoptosis, and this pathway is often lost during tumorigenesis. Ultraviolet radiation B (UVB) exposure activates diverse cellular responses, including DNA damage and apoptosis. In this study, we investigated whether the E6 oncogene alone or in combination with UVB dysregulate some components of the TGFß pathway in the epidermis of K14E6 mice. We used 8-day-old K14E6 and non-transgenic mice irradiated and unirradiated with a single dose of UVB. We found that the E6 oncogene and UVB irradiation impair the TGFß pathway in epidermis of K14E6 mice by downregulation of the TGFß type II receptor (TßRII). This loss of TßRII prevents downstream activation of Smad2 and target genes as p15, an important regulator of cell cycle progression. In summary, the TGFß signalling in cells of the epidermis is downregulated in our mouse model by both the E6 oncoprotein and the UVB irradiation.

Papillomavirus E6 oncoprotein up-regulates occludin and ZO-2 expression in ovariectomized mice epidermis.

We have studied the expression of the tight junction proteins (TJ) occludin, claudin-1 and ZO-2 in the epidermis of female mice. We observed a peak of expression of these proteins at postnatal day 7 and a decrease in 6 week-old mice to values similar to those found in newborn animals. We explored if the expression of the E6 oncoprotein from high-risk human papilloma virus type 16 (HPV16) in the skin of transgenic female mice (K14E6), altered TJ protein expression in a manner sensitive to ovarian hormones. We observed that in ovariectomized mice E6 up-regulates the expression of occludin and ZO-2 in the epidermis and that this effect was canceled by 17ß-estradiol. Progesterone instead induced occludin and ZO-2 over-expression. However, the decreased expression of occludin and ZO-2 induced by 17ß-estradiol in the epidermis was not overturned by E6 or progesterone. In addition, we employed MDCK cells transfected with E6, and observed that ZO-2 delocalizes from TJs and accumulates in the cell nuclei due to a decrease in the turnover rate of the protein. These results reinforce the view of 17ß-estradiol and E6 as risk factors for the development of cancer through effects on expression and mislocalization of TJ proteins.

Role of SLC5A8 as a Tumor Suppressor in Cervical Cancer.

BACKGROUND: The SLC5A8 gene is silenced in various types of cancer, including cervical cancer; we recently demonstrated that the SLC5A8 gene is also silenced in cervical cancer by hypermethylation of the CpG island in the gene promoter. This study aims to analyze whether SLC5A8 could be a tumor suppressor in cervical cancer. METHODS: After ectopic expressing SLC5A8 in the HeLa cell line, we evaluated its effects on cell behavior both in vitro and in vivo by Confocal immunofluorescence, cell proliferation, migration assays, and xenograft transplants. RESULTS: Overexpression of SLC5A8 in the HeLa cell line decreased its proliferation by arresting cancer cells in the G1 phase and inhibiting cellular migration. Furthermore, we observed that pyruvate increased the SLC5A8 effect, inducing S-phase arrest and inhibiting the entry into mitosis. SLC5A8 decreased tumor growth in xenograft transplants, significantly reducing the volume and tumor weight at 35 days of analysis. CONCLUSIONS: In summary, our results indicate that SLC5A8 has a role as a tumor suppressor in cervical cancer.

Predictors of Endocrine Resistance in a Cohort of Mexican Breast Cancer Patients.

Purpose: This study aimed to determine the prevalence of endocrine resistance in a cohort of Hispanic Mexican breast cancer (BC) patients receiving care at Instituto Nacional de Cancerología (INCan). Additionally, the clinical-pathological factors associated with endocrine resistance were identified, and their impact on patient survival was explored. Methods: A retrospective analysis of 200 BC patients who attended INCan between 2012 and 2016 with estrogen receptor (ER) and progesterone receptor (PR) positive tumors was made. Endocrine resistance was defined according to the International Consensus Guidelines for Advance Breast Cancer 2 definition. Their clinicopathological characteristics were analyzed to determine the association with endocrine resistance presence. We used sensitivity analyses and multivariate-adjusted logistic regressions, Kaplan-Meier curves, and multivariate-adjusted Cox regressions. P-value < 0.05 was considered as statistically significant. Results: Endocrine resistance was observed in 32.5% of patients included in this study. The distinction between hormone resistance and sensitivity was influenced by tumor size and node status. It had a mean diameter of 7.15 cm in endocrine resistance cases compared to 5.71 cm in non-endocrine, with N3 status present in 20% of endocrine resistance cases versus only 2.2% in non-endocrine (p-value < 0.001). The clinical stage exhibited a strong association with endocrine resistance (Risk Ratio [RR] 4.39, 95% confidence interval [95%CI] 1.50, 11.43). Furthermore, endocrine resistance significantly impacted mortality during the follow-up, with a Hazard Ratio [HR] of 23.7 (95%CI 5.20, 108.42) in multivariable-adjusted models. However, a complete pathological response reduced the endocrine resistance risk, as demonstrated by a Risk Ratio (RR) of 0.15 (95% CI 0.03, 0.75). Conclusions: Advanced clinical stage at diagnosis predicted endocrine resistance in Hispanic Mexican BC patients. Complete pathologic response in locally advanced disease patients was also a key predictor of endocrine resistance. These results indicated that endocrine resistance was a critical factor in BC during follow-up.

Toxoplasma gondii invasion and replication within neonate mouse astrocytes and changes in apoptosis related molecules.

Toxoplasma gondii invades any nucleated cell, but different replication speed and effects on survival/apoptosis processes have been found depending on cell type. There are scarce and controversial results regarding the effect of this parasite on host cell apoptosis within the brain. The invasion and replication of T. gondii RH strain within newborn mouse astrocytes were evaluated in the present work. At 4 hpi>90% cells were infected and harbored one to three parasitophorous vacuoles with one tazchyzoite/vacuole. Cell culture massive destruction started after 24 h of exposure, when the parasite already replicated, with a duplication time of around 5 h. The effect of T. gondii infection on apoptosis was also evaluated by changes in some anti- and pro-apoptotic markers. At early infection times decreased Bcl-2, Survivin and PUMA and increased Noxa expression was found, although Survivin and Noxa mRNA levels reverted towards an anti-apoptotic phenotype after 6 h. Caspases 3/7 activity decreased three hours after infection, although it returned to normal levels thereafter. This enzymatic activity was strongly stimulated by Cisplatin (anti-neoplasic drug) but it was inhibited by previous T. gondii infection. Likewise, parasite invasion prevented PARP-1 fragmentation and cell apoptosis induced by the same drug. In conclusion, astrocytes seem to activate some apoptosis signals shortly after infection, but the parasite takes control of the cell and inhibits programmed death for up to 24 h, until it replicates, egresses and generates cellular destruction.

Molecular mechanisms of resveratrol as chemo and radiosensitizer in cancer.

One of the primary diseases that cause death worldwide is cancer. Cancer cells can be intrinsically resistant or acquire resistance to therapies and drugs used for cancer treatment through multiple mechanisms of action that favor cell survival and proliferation, becoming one of the leading causes of treatment failure against cancer. A promising strategy to overcome chemoresistance and radioresistance is the co-administration of anticancer agents and natural compounds with anticancer properties, such as the polyphenolic compound resveratrol (RSV). RSV has been reported to be able to sensitize cancer cells to chemotherapeutic agents and radiotherapy, promoting cancer cell death. This review describes the reported molecular mechanisms by which RSV sensitizes tumor cells to radiotherapy and chemotherapy treatment.

Mutant p53 Gain-of-Function Induces Migration and Invasion through Overexpression of miR-182-5p in Cancer Cells.

The master-key TP53 gene is a tumor suppressor that is mutated in more than 50% of human cancers. Some p53 mutants lose their tumor suppressor activity and acquire new oncogenic functions, known as a gain of function (GOF). Recent studies have shown that p53 mutants can exert oncogenic effects through specific miRNAs. We identified the differentially expressed miRNA profiles of the three most frequent p53 mutants (p53R273C, p53R248Q, and p53R175H) after their transfection into the Saos-2 cell line (null p53) as compared with p53WT transfected cells. The associations between these miRNAs and the signaling pathways in which they might participate were identified with miRPath Software V3.0. QRT-PCR was employed to validate the miRNA profiles. We observed that p53 mutants have an overall negative effect on miRNA expression. In the global expression profile of the human miRNome regulated by the p53R273C mutant, 72 miRNAs were underexpressed and 35 overexpressed; in the p53R175H miRNAs profile, our results showed the downregulation of 93 and upregulation of 10 miRNAs; and in the miRNAs expression profile regulated by the p53R248Q mutant, we found 167 decreased and 6 increased miRNAs compared with p53WT. However, we found overexpression of some miRNAs, like miR-182-5p, in association with processes such as cell migration and invasion. In addition, we explored whether the induction of cell migration and invasion by the p53R48Q mutant was dependent on miR-182-5p because we found overexpression of miR-182-5p, which is associated with processes such as cell migration and invasion. Inhibition of mutant p53R248Q and miR-182-5p increased FOXF2-MTSS1 levels and decreased cell migration and invasion. In summary, our results suggest that p53 mutants increase the expression of miR-182-5p, and this miRNA is necessary for the p53R248Q mutant to induce cell migration and invasion in a cancer cell model.