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"Carvalho, Tiago"
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Resistance to Gemcitabine in Pancreatic Ductal Adenocarcinoma: A Physiopathologic and Pharmacologic Review
by
Carvalho, Tiago M. A.
,
Alfarouk, Khalid Omer
,
Greco, Maria Raffaella
in
Adenocarcinoma
,
Autophagy
,
Cancer therapies
2022
Pancreatic ductal adenocarcinoma (PDAC) is a very aggressive tumor with a poor prognosis and inadequate response to treatment. Many factors contribute to this therapeutic failure: lack of symptoms until the tumor reaches an advanced stage, leading to late diagnosis; early lymphatic and hematic spread; advanced age of patients; important development of a pro-tumoral and hyperfibrotic stroma; high genetic and metabolic heterogeneity; poor vascular supply; a highly acidic matrix; extreme hypoxia; and early development of resistance to the available therapeutic options. In most cases, the disease is silent for a long time, andwhen it does become symptomatic, it is too late for ablative surgery; this is one of the major reasons explaining the short survival associated with the disease. Even when surgery is possible, relapsesare frequent, andthe causes of this devastating picture are the low efficacy ofand early resistance to all known chemotherapeutic treatments. Thus, it is imperative to analyze the roots of this resistance in order to improve the benefits of therapy. PDAC chemoresistance is the final product of different, but to some extent, interconnected factors. Surgery, being the most adequate treatment for pancreatic cancer and the only one that in a few selected cases can achieve longer survival, is only possible in less than 20% of patients. Thus, the treatment burden relies on chemotherapy in mostcases. While the FOLFIRINOX scheme has a slightly longer overall survival, it also produces many more adverse eventsso that gemcitabine is still considered the first choice for treatment, especially in combination with other compounds/agents. This review discusses the multiple causes of gemcitabine resistance in PDAC.
Journal Article
Shapes of hatred and violence in Shakespeare
2024
I use five Shakespearean plays to discuss how the meaning of the shapes of hatred and violence depend on individual character traits. In this sense, hatred and violence can either make comic characters meet some sort of reconciliation or self-destruction in the case of tragic characters. In The Comedy of Errors, the Dromio brothers, who are subject to violence from their master’s part, are the ones who can find redemption nonetheless. In The Merchant of Venice, the structural hatred between Shylock and Antonio seems to configure a form of meaning to them. In King Henry V, the enablement of violence during war time seems to suggest that the capacity for violence is inherent to every human being. This suggestion is carried over through Titus Andronicus, in which Shakespeare explores the traumatic effects of violence within a mythical realm. Finally, in Macbeth, we see how the protagonist, who is accustomed to the violence of war, can have his own nature changed when he is forced to unwillingly commit a murder outside the context of war. Neste artigo, abordo cinco peças de Shakespeare para discutir como o significado de formas de ódio e violência dependem de traços individuais de personagens. Nesse sentido, ódio e violência podem fazer com que personagens cômicos consigam alcançar alguma forma de reconciliação ou autodestruição no caso de personagens trágicos. N’A Comédia dos Erros, os irmãos Dromio, que são submetidos a violência por parte de seus donos, são os que encontram redenção apesar do sofrimento. N’O Mercador de Veneza, o ódio estrutural entre Antônio e Shylock parece configurar uma forma de sentido para eles. Em Henrique V, a habilitação de violência durante um período de guerra parece sugerir que a capacidade para violência é inerente ao ser humano. Essa sugestão é observada também em Tito Andrônico, em que Shakespeare explora os efeitos traumáticos da violência em uma esfera mítica. Finalmente, em Macbeth, vemos como um personagem acostumado com a violência da guerra pode ter sua própria natureza mudada quando é forçado a involuntariamente cometer um assassinato fora do contexto de guerra.
Journal Article
Tumor Microenvironment Features and Chemoresistance in Pancreatic Ductal Adenocarcinoma: Insights into Targeting Physicochemical Barriers and Metabolism as Therapeutic Approaches
by
Carvalho, Tiago M. A.
,
Cardone, Rosa A.
,
Greco, Maria Raffaella
in
Adenocarcinoma
,
Cancer therapies
,
Chemoresistance
2021
Currently, the median overall survival of PDAC patients rarely exceeds 1 year and has an overall 5-year survival rate of about 9%. These numbers are anticipated to worsen in the future due to the lack of understanding of the factors involved in its strong chemoresistance. Chemotherapy remains the only treatment option for most PDAC patients; however, the available therapeutic strategies are insufficient. The factors involved in chemoresistance include the development of a desmoplastic stroma which reprograms cellular metabolism, and both contribute to an impaired response to therapy. PDAC stroma is composed of immune cells, endothelial cells, and cancer-associated fibroblasts embedded in a prominent, dense extracellular matrix associated with areas of hypoxia and acidic extracellular pH. While multiple gene mutations are involved in PDAC initiation, this desmoplastic stroma plays an important role in driving progression, metastasis, and chemoresistance. Elucidating the mechanisms underlying PDAC resistance are a prerequisite for designing novel approaches to increase patient survival. In this review, we provide an overview of the stromal features and how they contribute to the chemoresistance in PDAC treatment. By highlighting new paradigms in the role of the stromal compartment in PDAC therapy, we hope to stimulate new concepts aimed at improving patient outcomes.
Journal Article
Development of Smartphone Apps for Skin Cancer Risk Assessment: Progress and Promise
2019
Skin cancer is a growing public health problem. Early and accurate detection is important, since prognosis and cost of treatment are highly dependent on cancer stage at detection. However, access to specialized health care professionals is not always straightforward, and population screening programs are unlikely to become implemented. Furthermore, there is a wide margin for improving the efficiency of skin cancer diagnostics. Specifically, the diagnostic accuracy of general practitioners and family physicians in differentiating benign and malignant skin tumors is relatively low. Both access to care and diagnostic accuracy fuel interest in developing smartphone apps equipped with algorithms for image analyses of suspicious lesions to detect skin cancer. Based on a recent review, seven smartphone apps claim to perform image analysis for skin cancer detection, but as of October 2018, only three seemed to be active. These apps have been criticized in the past due to their lack of diagnostic accuracy. Here, we review the development of the SkinVision smartphone app, which has more than 900,000 users worldwide. The latest version of the SkinVision app (October 2018) has a 95% sensitivity (78% specificity) for detection of skin cancer. The current accuracy of the algorithm may warrant the use of this app as an aid by lay users or general practitioners. Nonetheless, for mobile health apps to become broadly accepted, further research is needed on their health impact on the health system and the user population. Ultimately, mobile health apps could become a powerful tool to reduce health care costs related to skin cancer management and minimize the morbidity of skin cancer in the population.
Journal Article
Evidence-based impact projections of single-dose human papillomavirus vaccination in India: a modelling study
by
Kataria, Ishu
,
Lucas, Eric
,
Siddiqui, Mariam
in
Female
,
Hematology, Oncology, and Palliative Medicine
,
Human papillomavirus 16
2022
Despite the high burden of cervical cancer, access to preventive measures remains low in India. A single-dose immunisation schedule could facilitate the scale-up of human papillomavirus (HPV) vaccination, contributing to global elimination of cervical cancer. We projected the effect of single-dose quadrivalent HPV vaccination in India in comparison with no vaccination or to a two-dose schedule.
In this modelling study, we adapted an HPV transmission model (EpiMetHeos) to Indian data on sexual behaviour (from the Demographic and Health Survey and the Indian National AIDS Control Organisation), HPV prevalence data (from two local surveys, from the states of Tamil Nadu and West Bengal), and cervical cancer incidence data (from Cancer Incidence in Five Continents for the period 2008–12 [volume XI], and the Indian National Centre for Disease Informatics and Research for the period 2012–16). Using the model, we projected the nationwide and state-specific effect of HPV vaccination on HPV prevalence and cervical cancer incidence, and lifetime risk of cervical cancer, for 100 years after the introduction of vaccination or in the first 50 vaccinated birth cohorts. Projections were derived under a two-dose vaccination scenario assuming life-long protection and under a single-dose vaccination scenario with protection duration assumptions derived from International Agency for Research on Cancer (IARC) India vaccine trial data, in combination with different vaccination coverages and catch-up vaccination age ranges. We used two thresholds to define cervical cancer elimination: an age-standardised incidence rate of less than 4 cases per 100 000 woman-years, and standardised lifetime risk of less than 250 cases per 100 000 women born.
Assuming vaccination in girls aged 10 years, with 90% coverage, and life-long protection by two-dose or single-dose schedule, HPV vaccination could reduce the prevalence of HPV16 and HPV18 infection by 97% (80% UI 96–99) in 50 years, and the lifetime risk of cervical cancer by 71–78% from 1067 cases per 100 000 women born under a no vaccination scenario to 311 (80% UI 284–339) cases per 100 000 women born in the short term and 233 (219–252) cases per 100 000 women born in the long term in vaccinated cohorts. Under this scenario, we projected that the age-standardised incidence rate threshold for elimination could be met across India (range across Indian states: 1·6 cases [80% UI 1·5–1·7] to 4·0 cases [3·8–4·4] per 100 000 woman-years), while the complementary threshold based on standardised lifetime risk was attainable in 17 (68%) of 25 states, but not nationwide (range across Indian states: 207 cases [80% UI 194–223] to 477 cases [447–514] per 100 000 women born). Under the considered assumptions of waning vaccine protection, single-dose vaccination was projected to have a 21–100% higher per-dose efficiency than two-dose vaccination. Single-dose vaccination with catch-up for girls and women aged 11–20 years was more impactful than two-dose vaccination without catch-up, with reduction of 39–65% versus 38% in lifetime risk of cervical cancer across the ten catch-up birth cohorts and the first ten routine vaccination birth cohorts.
Our evidence-based projections suggest that scaling up cervical cancer prevention through single-dose HPV vaccination could substantially reduce cervical cancer burden in India.
The Bill & Melinda Gates Foundation.
Journal Article
Targeting the Stromal Pro-Tumoral Hyaluronan-CD44 Pathway in Pancreatic Cancer
by
Carvalho, Tiago M. A.
,
Reshkin, Stephan Joel
,
Cardone, Rosa A.
in
Adenocarcinoma - drug therapy
,
Adenocarcinoma - genetics
,
Adenocarcinoma - pathology
2021
Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignancies. Present-day treatments have not shown real improvements in reducing the high mortality rate and the short survival of the disease. The average survival is less than 5% after 5 years. New innovative treatments are necessary to curtail the situation. The very dense pancreatic cancer stroma is a barrier that impedes the access of chemotherapeutic drugs and at the same time establishes a pro-proliferative symbiosis with the tumor, thus targeting the stroma has been suggested by many authors. No ideal drug or drug combination for this targeting has been found as yet. With this goal in mind, here we have explored a different complementary treatment based on abundant previous publications on repurposed drugs. The cell surface protein CD44 is the main receptor for hyaluronan binding. Many malignant tumors show over-expression/over-activity of both. This is particularly significant in pancreatic cancer. The independent inhibition of hyaluronan-producing cells, hyaluronan synthesis, and/or CD44 expression, has been found to decrease the tumor cell’s proliferation, motility, invasion, and metastatic abilities. Targeting the hyaluronan-CD44 pathway seems to have been bypassed by conventional mainstream oncological practice. There are existing drugs that decrease the activity/expression of hyaluronan and CD44: 4-methylumbelliferone and bromelain respectively. Some drugs inhibit hyaluronan-producing cells such as pirfenidone. The association of these three drugs has never been tested either in the laboratory or in the clinical setting. We present a hypothesis, sustained by hard experimental evidence, suggesting that the simultaneous use of these nontoxic drugs can achieve synergistic or added effects in reducing invasion and metastatic potential, in PDAC. A non-toxic, low-cost scheme for inhibiting this pathway may offer an additional weapon for treating pancreatic cancer.
Journal Article
Unbiased Metagenomic Sequencing for Pediatric Meningitis in Bangladesh Reveals Neuroinvasive Chikungunya Virus Outbreak and Other Unrealized Pathogens
by
Rahman, Hafizur
,
Dimitrov, Boris
,
Ramesh, Akshaya
in
Antigens
,
Bangladesh
,
Bangladesh - epidemiology
2019
Globally, there are an estimated 10.6 million cases of meningitis and 288,000 deaths every year, with the vast majority occurring in low- and middle-income countries. In addition, many survivors suffer from long-term neurological sequelae. Most laboratories assay only for common bacterial etiologies using culture and directed PCR, and the majority of meningitis cases lack microbiological diagnoses, impeding institution of evidence-based treatment and prevention strategies. We report here the results of a validation and application study of using unbiased metagenomic sequencing to determine etiologies of idiopathic (of unknown cause) cases. This included CSF from patients with known neurologic infections, with idiopathic meningitis, and without infection admitted in the largest children’s hospital of Bangladesh and environmental samples. Using mNGS and machine learning, we identified and confirmed an etiology (viral or bacterial) in 40% of idiopathic cases. We detected three instances of Chikungunya virus (CHIKV) that were >99% identical to each other and to a strain previously recognized to cause systemic illness only in 2017. CHIKV qPCR of all remaining stored 472 CSF samples from children who presented with idiopathic meningitis in 2017 at the same hospital uncovered an unrecognized CHIKV meningitis outbreak. CSF mNGS can complement conventional diagnostic methods to identify etiologies of meningitis, and the improved patient- and population-level data can inform better policy decisions. The burden of meningitis in low-and-middle-income countries remains significant, but the infectious causes remain largely unknown, impeding institution of evidence-based treatment and prevention decisions. We conducted a validation and application study of unbiased metagenomic next-generation sequencing (mNGS) to elucidate etiologies of meningitis in Bangladesh. This RNA mNGS study was performed on cerebrospinal fluid (CSF) specimens from patients admitted in the largest pediatric hospital, a World Health Organization sentinel site, with known neurologic infections ( n = 36), with idiopathic meningitis ( n = 25), and with no infection ( n = 30), and six environmental samples, collected between 2012 and 2018. We used the IDseq bioinformatics pipeline and machine learning to identify potentially pathogenic microbes, which we then confirmed orthogonally and followed up through phone/home visits. In samples with known etiology and without infections, there was 83% concordance between mNGS and conventional testing. In idiopathic cases, mNGS identified a potential bacterial or viral etiology in 40%. There were three instances of neuroinvasive Chikungunya virus (CHIKV), whose genomes were >99% identical to each other and to a Bangladeshi strain only previously recognized to cause febrile illness in 2017. CHIKV-specific qPCR of all remaining stored CSF samples from children who presented with idiopathic meningitis in 2017 ( n = 472) revealed 17 additional CHIKV meningitis cases, exposing an unrecognized meningitis outbreak. Orthogonal molecular confirmation, case-based clinical data, and patient follow-up substantiated the findings. Case-control CSF mNGS surveys can complement conventional diagnostic methods to identify etiologies of meningitis, conduct surveillance, and predict outbreaks. The improved patient- and population-level data can inform evidence-based policy decisions. IMPORTANCE Globally, there are an estimated 10.6 million cases of meningitis and 288,000 deaths every year, with the vast majority occurring in low- and middle-income countries. In addition, many survivors suffer from long-term neurological sequelae. Most laboratories assay only for common bacterial etiologies using culture and directed PCR, and the majority of meningitis cases lack microbiological diagnoses, impeding institution of evidence-based treatment and prevention strategies. We report here the results of a validation and application study of using unbiased metagenomic sequencing to determine etiologies of idiopathic (of unknown cause) cases. This included CSF from patients with known neurologic infections, with idiopathic meningitis, and without infection admitted in the largest children’s hospital of Bangladesh and environmental samples. Using mNGS and machine learning, we identified and confirmed an etiology (viral or bacterial) in 40% of idiopathic cases. We detected three instances of Chikungunya virus (CHIKV) that were >99% identical to each other and to a strain previously recognized to cause systemic illness only in 2017. CHIKV qPCR of all remaining stored 472 CSF samples from children who presented with idiopathic meningitis in 2017 at the same hospital uncovered an unrecognized CHIKV meningitis outbreak. CSF mNGS can complement conventional diagnostic methods to identify etiologies of meningitis, and the improved patient- and population-level data can inform better policy decisions.
Journal Article
The Pros and Cons of Estrogens in Prostate Cancer: An Update with a Focus on Phytoestrogens
by
Carvalho, Tiago M. A.
,
Vaz, Cátia V.
,
Figueira, Marília I.
in
Androgens
,
Cancer
,
Carcinogenesis
2024
The role of estrogens in prostate cancer (PCa) is shrouded in mystery, with its actions going from angelic to devilish. The findings by Huggins and Hodges establishing PCa as a hormone-sensitive cancer have provided the basis for using estrogens in therapy. However, despite the clinical efficacy in suppressing tumor growth and the panoply of experimental evidence describing its anticarcinogenic effects, estrogens were abolished from PCa treatment because of the adverse secondary effects. Notwithstanding, research work over the years has continued investigating the effects of estrogens, reporting their pros and cons in prostate carcinogenesis. In contrast with the beneficial therapeutic effects, many reports have implicated estrogens in the disruption of prostate cell fate and tissue homeostasis. On the other hand, epidemiological data demonstrating the lower incidence of PCa in Eastern countries associated with a higher consumption of phytoestrogens support the beneficial role of estrogens in counteracting cancer development. Many studies have investigated the effects of phytoestrogens and the underlying mechanisms of action, which may contribute to developing safe estrogen-based anti-PCa therapies. This review compiles the existing data on the anti- and protumorigenic actions of estrogens and summarizes the anticancer effects of several phytoestrogens, highlighting their promising features in PCa treatment.
Journal Article
Sliding Shilnikov connection in Filippov-type predator–prey model
by
Gonçalves, Luiz Fernando
,
Duarte Novaes, Douglas
,
Carvalho, Tiago
in
Automotive Engineering
,
Chaos theory
,
Classical Mechanics
2020
Recently, a piecewise smooth differential system was derived as a model of a 1 predator–2 prey interaction where the predator feeds adaptively on its preferred prey and an alternative prey. In such a model, strong evidence of chaotic behavior was numerically found. Here, we revisit this model and prove the existence of a Shilnikov sliding connection when the parameters are taken in a codimension one submanifold of the parameter space. As a consequence of this connection, we conclude, analytically, that the model behaves chaotically for an open region of the parameter space.
Journal Article
Cancer Associated Fibroblast (CAF) Regulation of PDAC Parenchymal (CPC) and CSC Phenotypes Is Modulated by ECM Composition
by
Carvalho, Tiago M. A.
,
Zeeberg, Katrine
,
Tomasini, Richard
in
Adenocarcinoma
,
Behavior
,
Cancer
2022
Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest of all cancers, having one of the lowest five-year survival rates. One of its hallmarks is a dense desmoplastic stroma consisting in the abnormal accumulation of extracellular matrix (ECM) components, especially Collagen I. This highly fibrotic stroma embeds the bulk cancer (parenchymal) cells (CPCs), cancer stem cells (CSCs) and the main producers of the stromal reaction, the Cancer Associated Fibroblasts (CAFs). Little is known about the role of the acellular ECM in the interplay of the CAFs with the different tumor cell types in determining their phenotypic plasticity and eventual cell fate. Methods: Here, we analyzed the role of ECM collagen I in modulating the effect of CAF-derived signals by incubating PDAC CPCs and CSCs grown on ECM mimicking early (low collagen I levels) and late (high collagen I levels) stage PDAC stroma with conditioned medium from primary cultured CAFs derived from patients with PDAC in a previously described three-dimensional (3D) organotypic model of PDAC. Results: We found that CAFs (1) reduced CPC growth while favoring CSC growth independently of the ECM; (2) increased the invasive capacity of only CPCs on the ECM mimicking the early tumor; and (3) favored vasculogenic mimicry (VM) especially of the CSCs on the ECM mimicking an early tumor. Conclusions: We conclude that the CAFs and acellular stromal components interact to modulate the tumor behaviors of the PDAC CPC and CSC cell types and drive metastatic progression by stimulating the phenotypic characteristics of each tumor cell type that contribute to metastasis.
Journal Article