Pinheiro, J. | Search bioRxiv

bioRxiv2022

Resistance to EGFR inhibitors in lung cancer occurs through horizontal transfer and is associated with increased caveolins expression

Resistance to treatment is a major clinical problem and a major cause of cancer-related deaths. Understanding the biological basis of resistance acquisition is of utmost importance to improve the clinical management of cancer patients. NGS analysis of human lung cancer (LC) tumors from patients that relapsed after treatment with EGFR-tyrosine kinase inhibitors (TKI), revealed that the p.T790M resistance mutation is not present in all the relapsing tumor cells, suggesting that LC cells can become resistant even if not carrying the p.T790M mutation. Using in vitro treatments with conditioned medium (CM) and in vivo co-inoculation experiments, we show that LC cells sensitive to EGFR-TKIs (S cells) acquire resistance faster when treated with CM from LC cells resistant to EGFR-TKIs (R cells) or when co-inoculated with R cells in opposite flanks of the same animal. Importantly, we show that acquisition of resistance is not due to the emergence of subpopulations of cancer cells with new resistance mutations. Using transcriptomics, we show that acquisition of resistance is associated with upregulation of genes involved in endocytosis, namely caveolins CAV1 and CAV2. These findings were validated in human clinical samples, where an increase in CAV1 and CAV2 expression was associated with tumor relapse after treatment with EGFR-TKIs. Our results suggest that acquisition of resistance to targeted therapies results from the combined effect of selection of cells harboring specific resistance mutations and horizontal transfer of the resistance phenotype. These findings may pave the way to bring intercellular communication into the realm of cancer treatment. One Sentence SummaryResistance to EGFR inhibitors is transferred horizontally between lung cancer cells and is associated with gain of expression of caveolins.

cancer biology↗

bioRxiv2021

Stabilin-1 plays a protective role against Listeria monocytogenes infection through the regulation of cytokine and chemokine production and immune cell recruitment

Scavenger receptors are part of a complex surveillance system expressed by host cells to efficiently orchestrate innate immune response against bacterial infections. Stabilin-1 (STAB-1) is a scavenger receptor involved in cell trafficking, inflammation and cancer, however its role in infection remains to be elucidated. Listeria monocytogenes (Lm) is a major intracellular human food-borne pathogen causing severe infections in susceptible hosts. Using a mouse model of infection, we demonstrate here that STAB-1 controls Lm-induced cytokine and chemokine production and immune cell accumulation in Lm-infected organs. We show that STAB-1 also regulates the recruitment of myeloid cells in response to Lm infection and contributes to clear circulating bacteria. In addition, whereas STAB-1 appears to promote bacterial uptake by macrophages, infection by pathogenic Listeria induces the down regulation of STAB-1 expression and its delocalization from the host cell membrane. We propose STAB-1 as a new SR involved in the control of Lm infection through the regulation of host defense mechanisms, a process that would be targeted by bacterial virulence factors to promote infection.

microbiology↗

bioRxiv2018

Psychosocial stress and central adiposity: A Brazilian study with users of the public health system

ObjectiveTo assess the association between indicators of psychosocial stress and central adiposity in adult users of the Unified Health System (SUS) from Southeast of Brazil.\n\nMethodsThis cross-sectional study was conducted with 384 adults (20 to 59 years old) from the city of Alegre, Southeastern Brazil. The simple random sample represented the population using the public health system of the municipality. The prevalence of obesity was based on the Body Mass Index, and central adiposity (dependent variable) was measured by waist circumference in centimeters. The independent variables were the following indicators of psychosocial stress: food and nutrition insecurity (yes/no), serum cortisol (g/dL), symptoms suggestive of depression using the Beck Depression Inventory-II [≥] 17 (yes/no), and altered blood pressure [≥] 130/85 mmHg (yes/no). Univariate linear regression was performed between central adiposity and each stress indicator, and later the models were adjusted for socioeconomic, health, and lifestyle variables. All analyses were stratified by rural and urban location.\n\nResultsThe prevalence of weight excess was 68.3%, and 71.5% of individuals presented an increased risk for metabolic complications related to central adiposity. Mean waist circumference scores for the rural and urban population were 89.3 {+/-} 12.7 cm and 92.9 {+/-} 14.7 cm, respectively (p = 0.012). Indicators of stress that were associated with central adiposity were: cortisol in the rural population and altered blood pressure in the urban population. This occurred both in the raw analysis and in the models adjusted for confounding factors.\n\nConclusionThe associations between stress and adiposity were different between rural (cortisol - inverse association) and urban (altered blood pressure) lifestyles, confirming the influence of local and psychosocial subsistence on the modulation of stress and on how individuals react or restrain stressors. Stress reduction strategies can be useful in public health programs designed to prevent or treat obesity.

genetics↗

bioRxiv2018

The protozoan Trichomonas vaginalis targets bacteria with laterally-acquired NlpC/P60 peptidoglycan hydrolases

Trichomonas vaginalis is a human eukaryotic pathogen and the causative agent of trichomoniasis, the most prevalent non-viral sexually transmitted infection worldwide. This extracellular protozoan parasite is intimately associated with the human vaginal mucosa and microbiota but key aspects of the complex interactions between the parasite and the vaginal bacteria remain elusive. We report that T. vaginalis has acquired, by lateral gene transfer from bacteria, genes encoding peptidoglycan hydrolases of the NlpC/P60 family. Two of the T. vaginalis enzymes were active against bacterial peptidoglycan, retaining the active site fold and specificity as DL-endopeptidases. The endogenous NlpC/P60 genes are transcriptionally up regulated in T. vaginalis when in the presence of bacteria. The over-expression of an exogenous copy produces a remarkable phenotype where the parasite is capable of competing out bacteria from mixed cultures, consistent with the biochemical activity of the enzyme in vitro. Our study highlights the relevance of the interactions of this eukaryotic pathogen with bacteria, a poorly understood aspect on the biology of this important human parasite.\n\nAuthor summaryTrichomonas vaginalis is a protozoan parasite that causes a very common sexually transmitted disease known as trichomoniasis. This extracellular parasite resides in the vagina where it is in close association with the mucosa and the local microbiota. Very little is known about the nature of the parasite-bacteria interactions. Here, we report that this parasite had acquired genes from bacteria which retained their original function producing active enzymes capable of degrading peptidoglycan, a polymer that is chemically unique to the cell envelope of bacteria. Our results indicate that these enzymes help the parasite compete out bacteria in mixed cultures. These observations suggest that these enzymes may be critical for the parasite to establish infection in the vagina, a body site that is densely colonised with bacteria. Our study further highlights the importance of understanding the interactions between pathogens and microbiota, as the outcomes of these interactions are increasingly understood to have important implications on health and disease.

microbiology↗

bioRxiv2018

Psychosocial stress and central adiposity: A Brazilian study with users of the public health system

ObjectiveTo assess the association between indicators of psychosocial stress and central adiposity in adult users of the Unified Health System (SUS) from Southeast of Brazil.\n\nMethodsThis cross-sectional study was conducted with 384 adults (20 to 59 years old) from the city of Alegre, Southeastern Brazil. The simple random sample represented the population using the public health system of the municipality. The prevalence of obesity was based on the Body Mass Index, and central adiposity (dependent variable) was measured by waist circumference in centimeters. The independent variables were the following indicators of psychosocial stress: food and nutrition insecurity (yes/no), serum cortisol (g/dL), symptoms suggestive of depression using the Beck Depression Inventory-II [≥] 17 (yes/no), and altered blood pressure [≥] 130/85 mmHg (yes/no). Univariate linear regression was performed between central adiposity and each stress indicator, and later the models were adjusted for socioeconomic, health, and lifestyle variables. All analyses were stratified by rural and urban location.\n\nResultsThe prevalence of weight excess was 68.3%, and 71.5% of individuals presented an increased risk for metabolic complications related to central adiposity. Mean waist circumference scores for the rural and urban population were 89.3 {+/-} 12.7 cm and 92.9 {+/-} 14.7 cm, respectively (p = 0.012). Indicators of stress that were associated with central adiposity were: cortisol in the rural population and altered blood pressure in the urban population. This occurred both in the raw analysis and in the models adjusted for confounding factors.\n\nConclusionThe associations between stress and adiposity were different between rural (cortisol - inverse association) and urban (altered blood pressure) lifestyles, confirming the influence of local and psychosocial subsistence on the modulation of stress and on how individuals react or restrain stressors. Stress reduction strategies can be useful in public health programs designed to prevent or treat obesity.

genetics↗