Clues on the dynamics of DNA replication in Giardia lamblia.

Genomic replication is a critical, regulated process that ensures accurate genetic information duplication. In eukaryotic cells, strategies have evolved to prevent conflicts between replication and transcription. Giardia lamblia, a binucleated protozoan, alternates between tetraploid and octaploid genomes during its cell cycle. Using single-molecule techniques like DNA combing and nanopore-based sequencing, we investigated the spatio-temporal organization of DNA replication, replication fork progression and potential head-on replication-transcription collisions in Giardia trophozoites. Our findings indicate that Giardia chromosomes are replicated from only a few active origins, which are widely spaced and exhibit faster replication rates compared to those in other protozoan parasites. Immunofluorescence assays revealed that ∼20% of trophozoites show asynchronous replication between nuclei. Forksense and gene ontology analyses disclosed that genes in regions with potential head-on collisions are linked to chromatin dynamics, cell cycle regulation and DNA replication/repair pathways, possibly explaining the observed asynchronous replication in part of the population. This study offers the first comprehensive view of replication dynamics in Giardia, which is the pathogen that causes giardiasis, a diarrheal disease impacting millions worldwide.

H2B.V demarcates divergent strand-switch regions, some tDNA loci, and genome compartments in Trypanosoma cruzi and affects parasite differentiation and host cell invasion.

Histone variants play a crucial role in chromatin structure organization and gene expression. Trypanosomatids have an unusual H2B variant (H2B.V) that is known to dimerize with the variant H2A.Z generating unstable nucleosomes. Previously, we found that H2B.V protein is enriched in tissue-derived trypomastigote (TCT) life forms, a nonreplicative stage of Trypanosoma cruzi, suggesting that this variant may contribute to the differences in chromatin structure and global transcription rates observed among parasite life forms. Here, we performed the first genome-wide profiling of histone localization in T. cruzi using epimastigotes and TCT life forms, and we found that H2B.V was preferentially located at the edges of divergent transcriptional strand switch regions, which encompass putative transcriptional start regions; at some tDNA loci; and between the conserved and disrupted genome compartments, mainly at trans-sialidase, mucin and MASP genes. Remarkably, the chromatin of TCT forms was depleted of H2B.V-enriched peaks in comparison to epimastigote forms. Interactome assays indicated that H2B.V associated specifically with H2A.Z, bromodomain factor 2, nucleolar proteins and a histone chaperone, among others. Parasites expressing reduced H2B.V levels were associated with higher rates of parasite differentiation and mammalian cell infectivity. Taken together, H2B.V demarcates critical genomic regions and associates with regulatory chromatin proteins, suggesting a scenario wherein local chromatin structures associated with parasite differentiation and invasion are regulated during the parasite life cycle.

Interpersonal ethnic-racial discrimination and tobacco products: The moderating role of critical action.

OBJECTIVE: The present study aimed to understand the role of critical action, sociopolitical participation, an essential form of consciousness in the relationship between interpersonal discrimination and the use of tobacco products. METHOD: The present study was part of a more extensive longitudinal study on students' genetic and environmental experiences. To examine these associations, 164 racially minoritized college students (Mage = 19.86, SD = 0.28) were surveyed for this study. RESULTS: Findings indicated that the relation between interpersonal ethnic-racial discrimination (IERD) and tobacco products was moderated by critical action. Specifically, IERD was associated with greater use of tobacco products when students had low critical consciousness-critical action. The relation between IERD and the use of tobacco products became nonsignificant when students had high critical action. CONCLUSIONS: Critical action was protective in mitigating increased tobacco use in the context of discrimination experiences. Research, clinical, and policy implications are discussed in efforts to reduce tobacco-related disparities among racially minoritized college students. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Platinum(IV) Prodrugs Incorporating an Indole-Based Derivative, 5-Benzyloxyindole-3-Acetic Acid in the Axial Position Exhibit Prominent Anticancer Activity.

Kinetically inert platinum(IV) complexes are a chemical strategy to overcome the impediments of standard platinum(II) antineoplastic drugs like cisplatin, oxaliplatin and carboplatin. In this study, we reported the syntheses and structural characterisation of three platinum(IV) complexes that incorporate 5-benzyloxyindole-3-acetic acid, a bioactive ligand that integrates an indole pharmacophore. The purity and chemical structures of the resultant complexes, P-5B3A, 5-5B3A and 56-5B3A were confirmed via spectroscopic means. The complexes were evaluated for anticancer activity against multiple human cell lines. All complexes proved to be considerably more active than cisplatin, oxaliplatin and carboplatin in most cell lines tested. Remarkably, 56-5B3A demonstrated the greatest anticancer activity, displaying GI50 values between 1.2 and 150 nM. Enhanced production of reactive oxygen species paired with the decline in mitochondrial activity as well as inhibition of histone deacetylase were also demonstrated by the complexes in HT29 colon cells.

Global DNA methylation and telomere length as markers of accelerated aging in people living with HIV and non-alcoholic fatty liver disease.

Metabolic-dysfunction-associated fatty liver disease (MAFLD) is a comorbidity that generally increases in people living with HIV (PLWH). This condition is usually accompanied by persistent inflammation and premature immune system aging. In this prospective cohort study, we describe a straightforward methodology for quantifying biomarkers of aging, such as DNA methylation and telomere length, in PLWH and in the context of another relevant condition, such as MAFLD. Fifty-seven samples in total, thirty-eight from PLWH and nineteen from non-PLWH participants with or without MAFLD, were obtained and subjected to DNA extraction from peripheral blood mononuclear cells (PBMCs). Global DNA methylation and telomere length quantification were performed using an adapted enzyme-linked immunosorbent assay (ELISA) and qPCR, respectively. The quantification results were analysed and corrected by clinically relevant variables in this context, such as age, sex, and metabolic syndrome. Our results show an increased association of these biomarkers in PLWH regardless of their MAFLD status. Thus, we propose including the quantification of these age-related factors in studies of comorbidities. This will allow a better understanding of the effect of comorbidities of HIV infection and MAFLD and prevent their effects in these populations in the future.

Effectiveness and tolerability of dolutegravir/lamivudine for the treatment of HIV-1 infection in clinical practice.

OBJECTIVES: To assess the effectiveness and tolerability of dolutegravir (DTG)/lamivudine (3TC) among treatment-naive and virologically suppressed treatment-experienced individuals in the multicentre cohort of the Spanish HIV/AIDS Research Network (CoRIS) during the years 2018-2021. METHODS: We used multivariable regression models to compare viral suppression (VS) [HIV RNA viral load (VL) <50 copies/mL] and the change in CD4 cell counts at 24 and 48 (±12) weeks after initiation with dolutegravir/lamivudine or other first-line ART regimens. RESULTS: We included 2160 treatment-naive subjects, among whom 401 (18.6%) started with dolutegravir/lamivudine. The remaining subjects started bictegravir (BIC)/emtricitabine (FTC)/tenofovir alafenamide (TAF) (n = 949, 43.9%), DTG + FTC/tenofovir disoproxil fumarate (TDF) (n = 282, 13.1%), DTG/3TC/abacavir (ABC) (n = 255, 11.8%), darunavir (DRV)/cobicistat(COBI)/FTC/TAF (n = 147, 6.8%) and elvitegravir (EVG)/COBI/FTC/TAF (n = 126, 5.8%). At 24 and 48 weeks after starting dolutegravir/lamivudine, 91.4% and 93.8% of the subjects, respectively, achieved VS. The probability of achieving VS with dolutegravir/lamivudine was not significantly different compared with any other regimen at 24 or 48 weeks, with the exception of a lower chance of achieving VS at 24 weeks for DRV/COBI/FTC/TAF (adjusted OR: 0.47; 95% CI: 0.30-0.74) compared with dolutegravir/lamivudine.For the analysis of treatment-experienced virally suppressed subjects we included 1456 individuals who switched to dolutegravir/lamivudine, among whom 97.4% and 95.5% maintained VS at 24 and 48 weeks, respectively. During the first 48 weeks after dolutegravir/lamivudine initiation, 1.0% of treatment-naive and 1.5% of treatment-experienced subjects discontinued dolutegravir/lamivudine due to an adverse event. CONCLUSIONS: In this large multicentre cohort, effectiveness and tolerability of dolutegravir/lamivudine were high among treatment-naive and treatment-experienced subjects.

Viral metagenomics unveils MW (Malawi) polyomavirus infection in Brazilian pediatric patients with acute respiratory disease.

Viral metagenomics has been extensively applied for the identification of emerging or poorly characterized viruses. In this study, we applied metagenomics for the identification of viral infections among pediatric patients with acute respiratory disease, but who tested negative for SARS-CoV-2. Twelve pools composed of eight nasopharyngeal specimens were submitted to viral metagenomics. Surprisingly, in two of the pools, we identified reads belonging to the poorly characterized Malawi polyomavirus (MWPyV). Then, the samples composing the positive pools were individually tested using quantitative polymerase chain reaction for identification of the MWPyV index cases. MWPyV-positive samples were also submitted to respiratory virus panel testing due to the metagenomic identification of different clinically important viruses. Of note, MWPyV-positive samples tested also positive for respiratory syncytial virus types A and B. In this study, we retrieved two complete MWPyV genome sequences from the index samples that were submitted to phylogenetic inference to investigate their viral origin. Our study represents the first molecular and genomic characterization of MWPyV obtained from pediatric patients in South America. The detection of MWPyV in acutely infected infants suggests that this virus might participate (coparticipate) in cases of respiratory symptoms. Nevertheless, future studies based on testing of a larger number of clinical samples and MWPyV complete genomes appear to be necessary to elucidate if this emerging polyomavirus might be clinically important.

Transmitted drug resistance to antiretroviral drugs in Spain during the period 2019-2021.

To evaluate the prevalence of transmitted drug resistance (TDR) to nucleoside and nonnucleoside reverse transcriptase inhibitors (NRTI, NNRTI), protease inhibitors (PI), and integrase strand transfer inhibitors (INSTI) in Spain during the period 2019-2021, as well as to evaluate transmitted clinically relevant resistance (TCRR) to antiretroviral drugs. Reverse transcriptase (RT), protease (Pro), and Integrase (IN) sequences from 1824 PLWH (people living with HIV) were studied. To evaluate TDR we investigated the prevalence of surveillance drug resistance mutations (SDRM). To evaluate TCRR (any resistance level ≥ 3), and for HIV subtyping we used the Stanford v.9.4.1 HIVDB Algorithm and an in-depth phylogenetic analysis. The prevalence of NRTI SDRMs was 3.8% (95% CI, 2.8%-4.6%), 6.1% (95% CI, 5.0%-7.3%) for NNRTI, 0.9% (95% CI, 0.5%-1.4%) for PI, and 0.2% (95% CI, 0.0%-0.9%) for INSTI. The prevalence of TCRR to NRTI was 2.1% (95% CI, 1.5%-2.9%), 11.8% for NNRTI, (95% CI, 10.3%-13.5%), 0.2% (95% CI, 0.1%-0.6%) for PI, and 2.5% (95% CI, 1.5%-4.1%) for INSTI. Most of the patients were infected by subtype B (79.8%), while the majority of non-Bs were CRF02_AG (n = 109, 6%). The prevalence of INSTI and PI resistance in Spain during the period 2019-2021 is low, while NRTI resistance is moderate, and NNRTI resistance is the highest. Our results support the use of integrase inhibitors as first-line treatment in Spain. Our findings highlight the importance of ongoing surveillance of TDR to antiretroviral drugs in PLWH particularly with regard to first-line antiretroviral therapy.

A traveling SARS-CoV-2 laboratory as part of a pandemic response among vulnerable Brazilian populations.

BACKGROUND: Brazil has been dramatically hit by the SARS-CoV-2 pandemic and is a world leader in COVID-19 morbidity and mortality. Additionally, the largest country of Latin America has been a continuous source of SARS-CoV-2 variants and shows extraordinary variability of the pandemic strains probably related to the country´s outstanding position as a Latin American economical and transportation hub. Not all regions of the country show sufficient infrastructure for SARS-CoV-2 diagnosis and genotyping which can negatively impact the pandemic response. METHODS: Due to this reason and to disburden the diagnostic system of the inner São Paulo State, the Butantan Institute established the Mobile Laboratory (in Portuguese: LabMovel) for SARS-CoV-2 testing which started a trip of the most important "hotspots" of the most populous Brazilian region. The LabMovel initiated in two important cities of the State: Aparecida do Norte (an important religious center) and the Baixada Santista region which incorporates the port of Santos, the busiest in Latin America. The LabMovel was fully equipped with an automatized system for SARS-CoV-2 diagnosis and sequencing/genotyping. It also integrated the laboratory systems for patient records and results divulgation including in the Federal Brazilian Healthcare System. RESULTS: Currently,16,678 samples were tested, among them 1,217 from Aparecida and 4,564 from Baixada Santista. We tracked the delta introductio in the tested regions with its high diversification. The established mobile SARS-CoV-2 laboratory had a major impact on the Public Health System of the included cities including timely delivery of the results to the healthcare agents and the Federal Healthcare system, evaluation of the vaccination status of the positive individuals in the background of exponential vaccination process in Brazil and scientific and technological divulgation of the fieldwork to the most vulnerable populations. CONCLUSIONS: The SARS-CoV-2 pandemic has demonstrated worldwide the importance of science to fight against this viral agent and the LabMovel shows that it is possible to integrate researchers, clinicians, healthcare workers and patients to take rapid actions that can in fact mitigate this and other epidemiological situations.

Black adolescents' racial discrimination and suicide behaviors: Testing perceived school safety as a protective moderator.

The current study examined associations between Black adolescents' (Mage = 15.55, SD = 1.23) racial discrimination and suicide behaviors (i.e., suicide ideation, suicide plan, and suicide attempts), and whether perceived school safety was a protective moderator. Furthermore, we tested gender differences in relations, which were not significant. Racial discrimination predicted greater suicide behaviors, and school safety informed less suicide behaviors. School safety moderated the relation between discrimination and suicide plan, such that at low school safety, discrimination predicted having a suicide plan but was not significant at high school safety. Furthermore, school safety moderated the relation between discrimination and suicide attempts. At low school safety, discrimination predicted more suicide attempts, but was not significant at high school safety.

Time elapsed since peruvian children's last dental care and head of household educational attainment: findings from a national database.

BACKGROUND: It has been documented that the parents' highest level of education has an impact on their children's access to oral health services and the frequency of their use.This study aimed to determine the association between time elapsed since peruvian children's last dental care and head of household educational attainment. METHODS: Cross-sectional study using a database of children aged 0 to 11 years, with a final sample of 8012 participants. The dependent variable in this study was the time elapsed since last dental care and the independent variable was the head of household educational attainment. Other covariates considered were natural region, area of residence, place of residence, altitude, wealth index, health insurance coverage, sex and age. Descriptive, bivariate and multivariate statistical analyses were applied. RESULTS: Time elapsed since last dental care in the year 2021 was 5.68 years (SD = 5.25). A hierarchical multiple linear regression analysis was performed, analyzing the variables dimensions by separate and joint models. When head of household educational attainment was analyzed, there was no statistical significance (p = 0.262); however, other models did (p < 0.05). Model 4, which addresses all dimensions, was significant (p < 0.001) with an R2% of 0.011 and constant equal to 5.788; it showed significance with place of dental care, health insurance, altitude and age. CONCLUSIONS: No association was found between head of household educational attainment and time elapsed since last dental care; however, the latter was associated with place of care, health insurance coverage, altitude and age in Peruvian children.

SARS-COV-2 genomic monitoring in the state of São Paulo unveils two emerging AY.43 sublineages.

Delta VOC is highly diverse with more than 120 sublineages already described as of November 30, 2021. In this study, through active monitoring of circulating severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants in the state of São Paulo, southeast Brazil, we identified two emerging sublineages from the ancestral AY.43 strain which were classified as AY.43.1 and AY.43.2. These sublineages were defined by the following characteristic nonsynonymous mutations ORF1ab:A4133V and ORF3a:T14I for the AY.43.1 and ORF1ab:G1155C for the AY.43.2 and our analysis reveals that they might have a likely-Brazilian origin. Much is still unknown regarding their dissemination in the state of São Paulo and Brazil as well as their potential impact on the ongoing vaccination process. However, the results obtained in this study reinforce the importance of genomic surveillance activity for timely identification of emerging SARS-CoV-2 variants which can impact the ongoing SARS-CoV-2 vaccination and public health policies.

Introduction of SARS-CoV-2 C.37 (WHO VOI lambda) in the Sao Paulo State, Southeast Brazil.

The Lambda variants of interest (VOI) (C37/GR/452Q.V1/21G) was initially reported in Lima, Peru but has gained rapid dissemination through other Latin American countries. Nevertheless, the dissemination and molecular epidemiology of the Lambda VOI in Brazil is unknown apart from a single case report. In this respect, we characterized the circulation of the SARS-CoV-2 Lambda VOI (C37/GR/452Q.V1/21G) in Sao Paulo State, Brazil. From March to June 2021, we identified seven Lambda isolates in a set of approximately 8000 newly sequenced genomes of the Network for Pandemic Alert of Emerging SARS-CoV-2 variants from Sao Paulo State. Interestingly, in three of the positive patients, the Lambda VOI infection was probably related to a contact transmission. These individuals were fully vaccinated to COVID-19 and presented mild symptoms. The remaining positive for Lambda VOI individuals showed different levels of COVID-19 symptoms and one of them needed hospitalization (score 5, WHO). In our study, we present a low level of Lambda VOI circulation in the Sao Paulo State. This reinforces the essential role of molecular surveillance for the effective SARS-CoV-2 pandemic response, especially in regard to circulating variants.

Low risk of bacterial co-infection, opportunistic diseases, and persistent immunosuppression in people living with HIV and COVID-19.

PURPOSE: SARS-CoV-2 infection produces lymphopenia and CD4+ T-cell decrease, which could lead to a higher risk of bacterial co-infection or impair immunological evolution in people living with HIV (PLWH). METHODS: We investigated the rate of co-infection and superinfection, and the evolution of CD4+ count and CD4+/CD8+ ratio, in hospitalized PLWH with COVID-19. RESULTS: From March to December 2020, 176 PLWH had symptomatic COVID-19 and 62 required hospitalization (median age, 56 years, 89% males). At admission, 7% and 13% of patients had leukocytosis or increased procalcitonin values and 37 (60%) received empiric antibiotic therapy, but no bacterial co-infection was diagnosed. There were seven cases of superinfection (12%), and one case of P. jiroveci pneumonia during ICU stay. No significant change in CD4+ count or CD4+/CD8+ ratio was observed after discharge. CONCLUSION: Bacterial co-infection is not frequent in PLWH with COVID-19. Immune recovery is observed in most of patients after the disease.

Antiretroviral treatment adherence and mental disorders: observational case-control study in people living with HIV in Spain.

Mental disorders hamper immunological control of HIV infection by exerting a negative influence on antiretroviral therapy (ART) adherence. We sought to address the possible relationship between non-adherence to antiretroviral treatment (ART), mental disorders and substance use in people living with HIV/AIDS (PLWHA) in Spain, which presents a high prevalence of intravenously transmitted HIV infection. We assessed 125 PLWHA attending regular outpatient follow-up. The main adherence measure was pill collection from the Hospital Pharmacy. We included sociodemographic variables, mental disorders diagnosis, and substance use in the 12 months prior to the assessment. Harmful alcohol consumption (OR: 6.834; 95% CI: 2.008-23.257; p = 0.002), suffering from depression (OR: 5.851; 95% CI: 1.470-23.283; p = 0.012) and being at risk of suicide (OR: 3.495; 95% CI: 1.136-10.757; p = 0.029) increased the likelihood of non-adherence. 29.6% of the sample had been infected via blood contact. HCV co-infection was present in 46.4% of the study sample, increasing the likelihood of non-adherence (OR: 3.223; 95% CI: 1.119-9.286; p = 0.030). Harmful alcohol use and some serious mental disorders (especially depression and suicide risk) are consistently associated with non-adherence to ART. HCV co-infection could be an important risk marker of non-adherence among PLWHA with a high prevalence of intravenous drug use.

Higher expression of proline dehydrogenase altered mitochondrial function and increased Trypanosoma cruzi differentiation in vitro and in the insect vector.

The pathogenic protist Trypanosoma cruzi uses kissing bugs as invertebrate hosts that vectorize the infection among mammals. This parasite oxidizes proline to glutamate through two enzymatic steps and one nonenzymatic step. In insect vectors, T. cruzi differentiates from a noninfective replicating form to nonproliferative infective forms. Proline sustains this differentiation, but to date, a link between proline metabolism and differentiation has not been established. In T. cruzi, the enzymatic steps of the proline-glutamate oxidation pathway are catalyzed exclusively by the mitochondrial enzymes proline dehydrogenase [TcPRODH, EC: 1.5.5.2] and Δ1-pyrroline-5-carboxylate dehydrogenase [TcP5CDH, EC: 1.2.1.88]. Both enzymatic steps produce reducing equivalents that are able to directly feed the mitochondrial electron transport chain (ETC) and thus produce ATP. In this study, we demonstrate the contribution of each enzyme of the proline-glutamate pathway to ATP production. In addition, we show that parasites overexpressing these enzymes produce increased levels of H2O2, but only those overexpressing TcP5CDH produce increased levels of superoxide anion. We show that parasites overexpressing TcPRODH, but not parasites overexpressing TcP5CDH, exhibit a higher rate of differentiation into metacyclic trypomastigotes in vitro. Finally, insect hosts infected with parasites overexpressing TcPRODH showed a diminished parasitic load but a higher percent of metacyclic trypomastigotes, when compared with controls. Our data show that parasites overexpressing both, PRODH and P5CDH had increased mitochondrial functions that orchestrated different oxygen signaling, resulting in different outcomes in relation to the efficiency of parasitic differentiation in the invertebrate host.

Vigilancia de la salud de los trabajadores expuestos a plaguicidas en el programa de control de vectores en México.

OBJETIVO: Analizar la interpretación e implementación de las políticas para la vigilancia de la salud de los trabajadores del programa para el control de vectores en México. Material y métodos. Se realizó un estudio transversal con métodos mixtos en cuatro estados de México; se incluyen entrevistas semiestructuradas, recolección de datos sobre los plaguicidas aplicados y los resultados del biomonitoreo realizado a los trabajadores y obtenidos de los registros estatales. Resul-tados. En todos los estados participantes se identificó un uso extensivo y variado de plaguicidas altamente peligrosos. Los procesos para monitorear la exposición ocupacional a inhibidores de acetilcolinesterasa son diferentes en cada uno de ellos y en ninguno se calculan los índices biológicos de ex-posición. CONCLUSIONES: El conocimiento sobre las políticas para vigilar la salud de los trabajadores debe fortalecerse y es necesario mejorar el contenido de las políticas vigentes de modo que abarquen los múltiples plaguicidas que aplican los trabajadores, así como sus posibles efectos combinados y a largo plazo.

Potent Chlorambucil-Platinum(IV) Prodrugs.

The DNA-alkylating derivative chlorambucil was coordinated in the axial position to atypical cytotoxic, heterocyclic, and non-DNA coordinating platinum(IV) complexes of type, [PtIV(HL)(AL)(OH)2](NO3)2 (where HL is 1,10-phenanthroline, 5-methyl-1,10-phenanthroline or 5,6-dimethyl-1,10-phenanthroline, AL is 1S,2S-diaminocyclohexane). The resultant platinum(IV)-chlorambucil prodrugs, PCLB, 5CLB, and 56CLB, were characterized using high-performance liquid chromatography, nuclear magnetic resonance, ultraviolet-visible, circular dichroism spectroscopy, and electrospray ionization mass spectrometry. The prodrugs displayed remarkable antitumor potential across multiple human cancer cell lines compared to chlorambucil, cisplatin, oxaliplatin, and carboplatin, as well as their platinum(II) precursors, PHENSS, 5MESS, and 56MESS. Notably, 56CLB was exceptionally potent in HT29 colon, Du145 prostate, MCF10A breast, MIA pancreas, H460 lung, A2780, and ADDP ovarian cell lines, with GI50 values ranging between 2.7 and 21 nM. Moreover, significant production of reactive oxygen species was detected in HT29 cells after treatment with PCLB, 5CLB, and 56CLB up to 72 h compared to chlorambucil and the platinum(II) and (IV) precursors.

Disrupting the MAD2L2-Rev1 Complex Enhances Cell Death upon DNA Damage.

DNA-damaging chemotherapy agents such as cisplatin have been the first line of treatment for cancer for decades. While chemotherapy can be very effective, its long-term success is often reduced by intrinsic and acquired drug resistance, accompanied by chemotherapy-resistant secondary malignancies. Although the mechanisms causing drug resistance are quite distinct, they are directly connected to mutagenic translesion synthesis (TLS). The TLS pathway promotes DNA damage tolerance by supporting both replication opposite to a lesion and inaccurate single-strand gap filling. Interestingly, inhibiting TLS reduces both cisplatin resistance and secondary tumor formation. Therefore, TLS targeting is a promising strategy for improving chemotherapy. MAD2L2 (i.e., Rev7) is a central protein in TLS. It is an essential component of the TLS polymerase zeta (ζ), and it forms a regulatory complex with Rev1 polymerase. Here we present the discovery of two small molecules, c#2 and c#3, that directly bind both in vitro and in vivo to MAD2L2 and influence its activity. Both molecules sensitize lung cancer cell lines to cisplatin, disrupt the formation of the MAD2L2-Rev1 complex and increase DNA damage, hence underlining their potential as lead compounds for developing novel TLS inhibitors for improving chemotherapy treatments.

Bioactive Platinum(IV) Complexes Incorporating Halogenated Phenylacetates.

A new series of cytotoxic platinum(IV) complexes (1-8) incorporating halogenated phenylacetic acid derivatives (4-chlorophenylacetic acid, 4-fluorophenylacetic acid, 4-bromophenylacetic acid and 4-iodophenylacetic acid) were synthesised and characterised using spectroscopic and spectrometric techniques. Complexes 1-8 were assessed on a panel of cell lines including HT29 colon, U87 glioblastoma, MCF-7 breast, A2780 ovarian, H460 lung, A431 skin, Du145 prostate, BE2-C neuroblastoma, SJ-G2 glioblastoma, MIA pancreas, the ADDP-resistant ovarian variant, and the non-tumour-derived MCF10A breast line. The in vitro cytotoxicity results confirmed the superior biological activity of the studied complexes, especially those containing 4-fluorophenylacetic acid and 4-bromophenylacetic acid ligands, namely 4 and 6, eliciting an average GI50 value of 20 nM over the range of cell lines tested. In the Du145 prostate cell line, 4 exhibited the highest degree of potency amongst the derivatives, displaying a GI50 value of 0.7 nM, which makes it 1700-fold more potent than cisplatin (1200 nM) and nearly 7-fold more potent than our lead complex, 56MESS (4.6 nM) in this cell line. Notably, in the ADDP-resistant ovarian variant cell line, 4 (6 nM) was found to be almost 4700-fold more potent than cisplatin. Reduction reaction experiments were also undertaken, along with studies aimed at determining the complexes' solubility, stability, lipophilicity, and reactive oxygen species production.