Mechanistic Insights about Sorafenib-, Valproic Acid- and Metformin-Induced Cell Death in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is among the main causes of death by cancer worldwide, representing about 80-90% of all liver cancers. Treatments available for advanced HCC include atezolizumab, bevacizumab, sorafenib, among others. Atezolizumab and bevacizumab are immunological options recently incorporated into first-line treatments, along with sorafenib, for which great treatment achievements have been reached. However, sorafenib resistance is developed in most patients, and therapeutical combinations targeting cancer hallmark mechanisms and intracellular signaling have been proposed. In this review, we compiled evidence of the mechanisms of cell death caused by sorafenib administered alone or in combination with valproic acid and metformin and discussed them from a molecular perspective.

ESX-3 secretion system in Mycobacterium: An overview.

Mycobacteria are microorganisms distributed in the environment worldwide, and some of them, such as Mycobacterium tuberculosis or M. leprae, are pathogenic. The hydrophobic mycobacterial cell envelope has low permeation and bacteria need to export products across their structure. Mycobacteria possess specialized protein secretion systems, such as the Early Secretory Antigenic Target 6 secretion (ESX) system. Five ESX loci have been described in M. tuberculosis, called ESX-1 to ESX-5. The ESX-3 secretion system has been associated with mycobacterial metabolism and growth. The locus of this system is highly conserved across mycobacterial species. Metallo-proteins regulate negative ESX-3 transcription in high conditions of iron and zinc. Moreover, this secretion system is part of an antioxidant regulatory pathway linked to Zinc. EccA3, EccB3, EccC3, EccD3, and EccE3 are components of the ESX-3 secretion machinery, whereas EsxG-EsxH, PE5-PPE4, and PE15-PPE20 are proteins secreted by this system. In addition, EspG3 and MycP3 are complementary proteins involved in transport and proteolysis respectively. This system is associated to mycobacterial virulence by releasing the bacteria from the phagosome and inhibiting endomembrane damage response. Furthermore, components of this system inhibit the host immune response by reducing the recognition of M. tuberculosis-infected cells. The components of the ESX-3 secretion system play a role in drug resistance and cell wall integrity. Moreover, the expression data of this system indicated that external and internal factors affect ESX-3 locus expression. This review provides an overview of new findings on the ESX-3 secretion system, its regulation, expression, and functions.

Sex, Age, and Comorbidities Are Associated with SARS-CoV-2 Infection, COVID-19 Severity, and Fatal Outcome in a Mexican Population: A Retrospective Multi-Hospital Study.

People with comorbidities and the male sex are at a higher risk of developing severe COVID-19. In the present study, we aim to investigate the associated factors for infection, severity, and death due to COVID-19 in a population from Nuevo León, México. Epidemiological COVID-19 data were collected from 65 hospitals from December 2020 to May 2022. A total of 75,232 cases were compiled from which 25,722 cases were positive for SARS-CoV-2. Male sex, older age, diabetes, obesity, and hypertension were associated with infection. In addition to the above-mentioned factors, renal disease, cardiovascular disease, and immunosuppression were found to be associated with increased COVID-19 severity. These factors, as well as neurological diseases, are also associated with death due to COVID-19. When comparing the different variants of SARs-CoV-2, the variant B1.1.519 increased the probability of death by 2.23 times compared to the AY.20 variant. Male sex, older age, diabetes, obesity, and hypertension are associated with SARS-CoV-2 infection, severity, and death. Along with the aforementioned comorbidities, renal disease, cardiovascular disease, and immunosuppression are also associated with severity and death. Another factor associated with death is the presence of neurological disease. The SARS-CoV-2 B1.1.519 variant increases the odds of death compared to the SARS-CoV-2 AY.20 variant.

Cell-type dependent regulation of pluripotency and chromatin remodeling genes by hydralazine.

BACKGROUND: The generation of induced pluripotent stem cells has opened the field of study for stem cell research, disease modeling and drug development. However, the epigenetic signatures present in somatic cells make cell reprogramming still an inefficient process. This epigenetic memory constitutes an obstacle in cellular reprogramming. Here, we report the effect of hydralazine (HYD) and valproic acid (VPA), two small molecules with proven epigenetic activity, on the expression of pluripotency genes in adult (aHF) and neonatal (nbHF) human fibroblasts. METHODS: aHF and nbHF were treated with HYD and/or VPA, and viability and gene expression assays for OCT4, NANOG, c-MYC, KLF4, DNMT1, TET3, ARID1A and ARID2 by quantitative PCR were performed. aHF and nbHF were transfected with episomal plasmid bearing Yamanaka factors (OCT4, SOX2, KLF4 and c-MYC) and exposed to HYD and VPA to determine the reprogramming efficiency. Methylation sensitive restriction enzyme (MSRE) qPCR assays were performed on OCT4 and NANOG promoter regions. Immunofluorescence assays were carried out for pluripotency genes on iPSC derived from aHF and nbHF. RESULTS: HYD upregulated the expression of OCT4 (2.5-fold) and NANOG (fourfold) genes but not c-Myc or KLF4 in aHF and had no significant effect on the expression of all these genes in nbHF. VPA upregulated the expression of NANOG (twofold) in aHF and c-MYC in nbHF, while it downregulated the expression of NANOG in nbHF. The combination of HYD and VPA canceled the OCT4 and NANOG overexpression induced by HYD in aHF, while it reinforced the effects of VPA on c-Myc expression in nbHF. The HYD-induced overexpression of OCT4 and NANOG in aHDF was not dependent on demethylation of gene promoters, and no changes in the reprogramming efficiency were observed in both cell populations despite the downregulation of epigenetic genes DNMT1, ARID1A, and ARID2 in nbHF. CONCLUSIONS: Our data provide evidence that HYD regulates the expression of OCT4 and NANOG pluripotency genes as well as ARID1A and ARID2 genes, two members of the SWI/SNF chromatin remodeling complex family, in normal human dermal fibroblasts.

Two New Dihydrosphingosine Analogs Against Mycobacterium tuberculosis Affect gltA1, lprQ, and rpsO Expression.

The emergence of multidrug-resistant (MDR) Mycobacterium tuberculosis strains threaten the control of tuberculosis. New antitubercular dihydrosphingosine analogs, named UCIs, have been evaluated in preclinical studies but their cellular and molecular mechanisms of action against M. tuberculosis are still unknown. The aim of this study was to evaluate the effect of UCI exposure on gene expression of drug-sensitive H37Rv and MDR CIBIN:UMF:15:99 clones of M. tuberculosis which were isolated, phenotypically, and genetically characterized, cultured to log phase and treated with UCI compounds; followed by total RNA isolation, reverse transcription and hybridization assays on Affymetrix genomic microarrays. Data were validated with RT-qPCR assays. As results, UCI-05 and UCI-14 exposure increased gltA1 expression in drug-sensitive H37Rv clones. Furthermore, UCI-05 increased lprQ expression in MDR CIBIN:UMF:15:99 M. tuberculosis clones while UCI-14 reduced the expression of this gene in drug-sensitive H37Rv clones. In addition, UCI-05 reduced rpsO expression in drug-sensitive H37Rv clones. We found gene expression alterations that suggest these molecules may alter carbon and lipid metabolism as well as interfere in the protein-producing machinery in M. tuberculosis.

NAT2 polymorphisms associated with the development of hepatotoxicity after first-line tuberculosis treatment in Mexican patients: From genotype to molecular structure characterization.

BACKGROUND AND AIMS: To assess the relevance of the slow acetylator phenotype based on NAT2 genotypes, among patients with pulmonary tuberculosis (PTB) that developed hepatotoxicity after first-line tuberculosis treatment in a Northeastern Mexican population. METHODS: Ninety one PTB patients were included, 7 of them developed hepatotoxicity. NAT2 SNPs (rs1801279, rs1041983, rs1801280, rs1799929, rs1799930, rs1208, and rs1799931) were genotyped by TaqMan allelic discrimination assay. Statistical analyses were performed using Epi Info statistical software 7.0 and SHEsisPlus for haplotype reconstruction. The NAT2 slow non-synonymous SNP were studied by molecular dynamic analysis (MDA). RESULTS: The frequency of the haplotype associated with slow acetylation status for PTB was 58%, and for with hepatotoxicity (PTB-H) represented 42.6%. Three haplotypes, NAT2*5Q, NAT2*5U, NAT2*5Va were exclusively present in seven PTB-H patients, (P = 0.01, P = 0.0006, P = 0.01, respectively). These haplotypes include the combination of two SNPs (I114T + R197Q or I114T + G286E). The effect of the SNPs on protein structure is to disrupt the CoA binding site affecting acetylation activity. CONCLUSION: Our study provides insight into slow acetylation NAT2 haplotypes associated with hepatotoxicity after first-line tuberculosis treatment, for first time, in a Mexican population. The molecular mechanism acts at the CoA binding site.

High Prevalence of Avian Influenza Virus Among Wild Waterbirds and Land Birds of Mexico.

Aquatic wild birds, especially waterfowl, have been long considered the main reservoirs of the avian influenza A virus; however, recent surveys have found an important prevalence of these viruses among land birds as well. Migration has been suggested as an important factor in the avian influenza virus dissemination. We aimed to estimate the prevalence of influenza A viruses in wild birds (waterbirds and land birds; resident and migratory) in eastern Mexico, where the three main North American migration flyways converge and where there was no previous information on this subject. We detected influenza with reverse transcription coupled with a PCR approach. Of the 534 birds sampled between 2010 and 2012, we detected the influenza A virus in a high proportion of birds (39%). Prevalence was particularly high in land birds (49%) when compared to aquatic birds (26%); there was no difference in overall prevalence between resident (39%) and migratory birds (39%). The high prevalence of the avian influenza virus in land birds was noteworthy in the innermost sampling areas in northern Mexico (Coahuila [82%] and Nuevo Leon [43%]).

Alta prevalencia del virus de la influenza aviar entre aves acuáticas silvestres y aves terrestres de México. Las aves silvestres acuáticas, especialmente las aves anseriformes, han sido consideradas durante mucho tiempo los principales reservorios del virus de la influenza aviar A; sin embargo, muestreos recientes también han encontrado una importante prevalencia de estos virus entre las aves terrestres. Se ha sugerido que la migración es un factor importante en la diseminación del virus de la influenza aviar. El objetivo de este estudio fue estimar la prevalencia de los virus de la influenza A en aves silvestres (aves acuáticas y terrestres; residentes y migratorias) en el este de México, donde convergen las tres rutas migratorias principales de América del Norte y donde no había información previa sobre este tema. Se detectó al virus de influenza mediante transcripción reversa acoplada a PCR. De las 534 aves muestreadas entre los años 2010 y 2012, se detectó al virus de la influenza A en una alta proporción de aves (39%). La prevalencia fue particularmente alta en las aves terrestres (49%) en comparación con las aves acuáticas (26%); no se observó diferencia en la prevalencia general entre las aves residentes (39%) y las migratorias (39%). La alta prevalencia del virus de la influenza aviar en las aves terrestres fue notable en las áreas de muestreo hacia el interior del norte de México (Coahuila [82%] y Nuevo León [43%]).

Role of esxG and esxH Genes in Drug-Resistant Mycobacterium.

Tuberculosis drug resistance (DR) is a global problem that is not fully elucidated. Previously, overexpression of esxG and esxH genes was reported in a multidrug-resistant (MDR) Mycobacterium tuberculosis isolate compared with a reference H37Rv strain. To evaluate the roles of esxG and esxH in DR, analysis of their regulatory and coding sequences in sensitive and resistant strains was performed, and the expression levels of their transcriptional regulators IdeR, Zur, and MntR were evaluated. esxG and esxH were expressed heterologously using mycobacterial constructs, and the orthologs Msmeg_0620 and Msmeg_0621 were attenuated in Mycobacterium smegmatis by antisense knockdown. We found no differences in the regulatory and coding sequences of esxG and esxH between the sensitive strain and the MDR isolate. Expression analysis of transcriptional regulators showed that ideR was upregulated in isoniazid (INH)-resistant isolates; in addition, growth inhibition of the M. smegmatis strain was observed in the presence of rifampicin (RIF) and INH when esxG and esxH were expressed heterologously, while faster growth in the presence of RIF was observed when the orthologs were attenuated. In conclusion, the expression of esxG and esxH altered the growth of Mycobacterium in the presence of INH and RIF, suggesting a potential association with DR.

LipF increases rifampicin and streptomycin sensitivity in a Mycobacterium tuberculosis surrogate.

BACKGROUND: Mortality due to tuberculosis (TB) has increased due to the development of drug resistance, the mechanisms of which have not been fully elucidated. Our research group identified a low expression of lipF gene in Mycobacterium tuberculosis clinical isolates with drug resistance. The aim of this work was to evaluate the effect of lipase F (LipF) expression on mycobacterial drug resistance. RESULTS: The effects of expressing lipF from Mycobacterium tuberculosis in Mycobacterium smegmatis on resistance to antituberculosis drugs were determined with resazurin microtiter assay plate and growth kinetics. Functionality of ectopic LipF was confirmed. LipF expression reduced the rifampicin (RIF) and streptomycin (STR) minimum inhibitory concentration (MIC) from 3.12 µg/mL to 1.6 µg/mL and 0.25 µg/mL to 0.06 µg/mL respectively, moreover a reduced M. smegmatis growth in presence of RIF and STR compared with that of a control strain without LipF expression (p < 0.05 and p < 0.01) was shown. CONCLUSIONS: LipF expression was associated with increased RIF and STR sensitivity in mycobacteria. Reduced LipF expression may contribute to the development of RIF and STR resistance in Mycobacterium species. Our findings provide information pertinent to understanding mycobacterial drug resistance mechanisms.

Association between vitamin D receptor gene polymorphisms and pulmonary tuberculosis in a Mexican population.

BACKGROUND AND AIMS: The impact of host genetic variation in susceptibility of tuberculosis is well documented. The vitamin D receptor gene (VDR) is a transacting transcription factor which mediates innate immune response by enhancing the expression of several antimicrobial peptides, including cathelicidin. An association between VDR polymorphisms with tuberculosis (TB) has been investigated in different ethnic groups; however there are contradictions and inconsistencies in the results. The aim of this study was to evaluate the association between polymorphisms of functional VDR with the susceptibility to pulmonary tuberculosis in a Mexican population. METHODS: A case-control study was performed in, 257 patients with pulmonary tuberculosis and 457 healthy controls recruited from: family medicine clinics of the Mexican Social Security Institute. The VDR gene polymorphisms Fok I (rs 2228570), BsmI (rs1544410), ApaI (rs7975232) and TaqI (rs731236) were genotyped by TaqMan assays. Statistical analysis was performed using: Epi Info V-7 and SNP Stats software. RESULTS: No statistically significant associations were observed in genotype and haplotype distribution between BsmI, ApaI and TaqI polymorphisms and disease susceptibility. The CC genotype for the VDR gene FokI was significantly more frequent in patients than in controls (29.6% versus 17.5%, OR=1.97; 95% CI=1.37-2.8, PC=0.0004). Moreover, TT genotype was decreased in patients as compared to the control group (24.1% versus 34.8%, OR=0.59; 95% CI=0.42-0.84, PC=0.004). CONCLUSION: To our best knowledge, this is the first case-control study that finds an association between CC genotype of FokI SNP in the VDR gene with pulmonary tuberculosis in Mexican patients. However more validation studies should be performed to prove our conclusions.

The polyaromatic hydrocarbon ß-naphthoflavone alters binding of YY1, Sp1, and Sp3 transcription factors to the Dp71 promoter in hepatic cells.

The smallest product of the Duchenne muscular dystrophy gene, dystrophin (Dp)71, is ubiquitously expressed in nonmuscle tissues. We previously showed that Dp71 expression in hepatic cells is modulated in part by stimulating factor 1 (Sp1), stimulating protein 3 (Sp3), and yin yang 1 (YY1) transcription factors, and that the polyaromatic hydrocarbon, ß-naphthoflavone (ß­NF), downregulates Dp71 expression. The aim of the present study was to determine whether ß­NF represses Dp71 expression by altering mRNA stability or its promoter activity. Reverse transcription­quantitative polymerase chain reaction was used to measure half­life mRNA levels in ß­NF­treated cells exposed to actinomycin D, an inhibitor of transcription, for 0, 4, 8, 12 and 16 h. Transient transfections with a plasmid carrying the Dp71 basal promoter fused to luciferase reporter gene were carried out in control and ß­NF­treated cells. Electrophoretic mobility shift assays (EMSAs) were performed with labeled probes, corresponding to Dp71 promoter sequences, and nuclear extracts of control and ß­NF­treated cells. To the best of our knowledge, the results demonstrated for the first time that this negative regulation takes place at the promoter level rather than the mRNA stability level. Interestingly, using EMSAs, ß­NF reduced binding of YY1, Sp1, and Sp3 to the Dp71 promoter. It also suggests that ß­NF may modulate the expression of other genes regulated by these transcription factors. In conclusion, ß­NF represses Dp71 expression in hepatic cells by altering binding of YY1, Sp1, and Sp3 to the Dp71 promoter.

Transcription factors YY1, Sp1 and Sp3 modulate dystrophin Dp71 gene expression in hepatic cells.

Dystrophin Dp71, the smallest product encoded by the Duchenne muscular dystrophy gene, is ubiquitously expressed in all non-muscle cells. Although Dp71 is involved in various cellular processes, the mechanisms underlying its expression have been little studied. In hepatic cells, Dp71 expression is down-regulated by the xenobiotic ß-naphthoflavone. However, the effectors of this regulation remain unknown. In the present study we aimed at identifying DNA elements and transcription factors involved in Dp71 expression in hepatic cells. Relevant DNA elements on the Dp71 promoter were identified by comparing Dp71 5'-end flanking regions between species. The functionality of these elements was demonstrated by site-directed mutagenesis. Using EMSAs and ChIP, we showed that the Sp1 (specificity protein 1), Sp3 (specificity protein 3) and YY1 (Yin and Yang 1) transcription factors bind to the Dp71 promoter region. Knockdown of Sp1, Sp3 and YY1 in hepatic cells increased endogenous Dp71 expression, but reduced Dp71 promoter activity. In summary, Dp71 expression in hepatic cells is carried out, in part, by YY1-, Sp1- and Sp3-mediated transcription from the Dp71 promoter.

Differential expression of putative drug resistance genes in Mycobacterium tuberculosis clinical isolates.

Understanding drug resistance in Mycobacterium tuberculosis requires an integrated analysis of strain lineages, mutations and gene expression. Previously, we reported the differential expression of esxG, esxH, infA, groES, rpmI, rpsA and lipF genes in a sensitive M. tuberculosis strain and in a multidrug-resistant clinical isolate. Here, we have evaluated the expression of these genes in 24 clinical isolates that belong to different lineages and have different drug resistance profiles. In vitro, growth kinetics analysis showed no difference in the growth of the clinical isolates, and thus drug resistance occurred without a fitness cost. However, a quantitative reverse transcription PCR analysis of gene expression revealed high variability among the clinical isolates, including those with similar drug resistance profiles. Due to the complexity of gene regulation pathways and the wide diversity of M. tuberculosis lineages, the use of gene expression as a molecular signature for drug resistance is not straightforward. Therefore, we recommend that the expression of M. tuberculosis genes be performed individually, and baseline expression levels should be verified among several different clinical isolates, before any further applications of these findings.

Correlations between major risk factors and closely related Mycobacterium tuberculosis isolates grouped by three current genotyping procedures: a population-based study in northeast Mexico.

The characteristics of tuberculosis (TB) patients related to a chain of recent TB transmissions were investigated. Mycobacterium tuberculosis (MTB) isolates (120) were genotyped using the restriction fragment length polymorphism-IS6110 (R), spacer oligotyping (S) and mycobacterial interspersed repetitive units-variable number of tandem repeats (M) methods. The MTB isolates were clustered and the clusters were grouped according to the similarities of their genotypes. Spearman's rank correlation coefficients between the groups of MTB isolates with similar genotypes and those patient characteristics indicating a risk for a pulmonary TB (PTB) chain transmission were ana- lysed. The isolates showing similar genotypes were distributed as follows: SMR (5%), SM (12.5%), SR (1.67%), MR (0%), S (46.67%), M (5%) and R (0%). The remaining 35 cases were orphans. SMR exhibited a significant correlation (p < 0.05) with visits to clinics, municipalities and comorbidities (primarily diabetes mellitus). S correlated with drug consumption and M with comorbidities. SMR is needed to identify a social network in metropolitan areas for PTB transmission and S and M are able to detect risk factors as secondary components of a transmission chain of TB.

Correlations between major risk factors and closely related Mycobacterium tuberculosis isolates grouped by three current enotyping procedures: a population-based study in northeast Mexico

The characteristics of tuberculosis (TB) patients related to a chain of recent TB transmissions were investigated. Mycobacterium tuberculosis (MTB) isolates (120) were genotyped using the restriction fragment length polymorphism-IS6110 (R), spacer oligotyping (S) and mycobacterial interspersed repetitive units-variable number of tandem repeats (M) methods. The MTB isolates were clustered and the clusters were grouped according to the similarities of their genotypes. Spearman’s rank correlation coefficients between the groups of MTB isolates with similar genotypes and those patient characteristics indicating a risk for a pulmonary TB (PTB) chain transmission were ana- lysed. The isolates showing similar genotypes were distributed as follows: SMR (5%), SM (12.5%), SR (1.67%), MR (0%), S (46.67%), M (5%) and R (0%). The remaining 35 cases were orphans. SMR exhibited a significant correlation (p < 0.05) with visits to clinics, municipalities and comorbidities (primarily diabetes mellitus). S correlated with drug consumption and M with comorbidities. SMR is needed to identify a social network in metropolitan areas for PTB transmission and S and M are able to detect risk factors as secondary components of a transmission chain of TB.

Measuring of Mycobacterium tuberculosis growth. A correlation of the optical measurements with colony forming units.

The quantification of colony forming units (cfu), turbidity, and optical density at 600 nm (OD600) measurements were used to evaluate Mycobacterium tuberculosis growth. Turbidity and OD600 measurements displayed similar growth curves, while cfu quantification showed a continuous growth curve. We determined the cfu equivalents to McFarland and OD600 units.

In vitro transcribed RNA molecules for the diagnosis of pandemic 2009 influenza A(H1N1) virus by real-time RT-PCR.

The 2009 influenza A(H1N1) outbreak allowed the implementation of new epidemiologic surveillance tools in several countries around the world. A new molecular protocol with appropriate sensitivity and specificity using real-time RT-PCR was developed by the Centers for Disease Control and Prevention (CDC) to identify the pandemic 2009 influenza A (H1N1) virus in human specimens. In the CDC protocol, positive controls are available only upon request and they are taken from cell cultures infected with 2009 influenza A(H1N1) virus, representing a handling risk for laboratory technicians. The poor availability of positive control materials in diagnostic laboratories may limit the public health response. The aim of the work presented in this paper was to develop positive controls for the diagnostic testing of influenza A(H1N1) virus that could be used in the CDC real-time RT-PCR protocol. A series of plasmid constructs bearing partial sequences of the viral genes were created and each construct was used as a template for in vitro transcription. RNA molecules were obtained successfully at high yield, i.e., 2×10(7) assays per microliter. Thus, the inclusion of these molecules in the influenza panel as positive controls is proposed. The in vitro transcribed RNA could also be used as quality standards in the design of international proficiency studies.

Measuring of Mycobacterium tuberculosis growth: a correlation of the optical measurements with colony forming units

The quantification of colony forming units (cfu), turbidity, and optical density at 600 nm (OD600) measurements were used to evaluate Mycobacterium tuberculosis growth. Turbidity and OD600 measurements displayed similar growth curves, while cfu quantification showed a continuous growth curve. We determined the cfu equivalents to McFarland and OD600 units.