Synthetic retinoid-mediated preconditioning of cancer-associated fibroblasts and macrophages improves cancer response to immune checkpoint blockade.

BACKGROUND: The proliferation of cancer-associated fibroblasts (CAFs) hampers drug delivery and anti-tumor immunity, inducing tumor resistance to immune checkpoint blockade (ICB) therapy. However, it has remained a challenge to develop therapeutics that specifically target or modulate CAFs. METHODS: We investigated the involvement of Meflin+ cancer-restraining CAFs (rCAFs) in ICB efficacy in patients with clear cell renal cell carcinoma (ccRCC) and urothelial carcinoma (UC). We examined the effects of Am80 (a synthetic retinoid) administration on CAF phenotype, the tumor immune microenvironment, and ICB efficacy in cancer mouse models. RESULTS: High infiltration of Meflin+ CAFs correlated with ICB efficacy in patients with ccRCC and UC. Meflin+ CAF induction by Am80 administration improved ICB efficacy in the mouse models of cancer. Am80 exerted this effect when administered prior to, but not concomitant with, ICB therapy in wild-type but not Meflin-deficient mice. Am80-mediated induction of Meflin+ CAFs was associated with increases in antibody delivery and M1-like tumor-associated macrophage (TAM) infiltration. Finally, we showed the role of Chemerin produced from CAFs after Am80 administration in the induction of M1-like TAMs. CONCLUSION: Our data suggested that Am80 administration prior to ICB therapy increases the number of Meflin+ rCAFs and ICB efficacy by inducing changes in TAM phenotype.

The antimicrobial potential of adarotene derivatives against Staphylococcus aureus strains.

Multidrug-resistant (MDR) pathogens are severely impacting our ability to successfully treat common infections. Here we report the synthesis of a panel of adarotene-related retinoids showing potent antimicrobial activity on Staphylococcus aureus strains (including multidrug-resistant ones). Fluorescence and molecular dynamic studies confirmed that the adarotene analogues were able to induce conformational changes and disfunctions to the cell membrane, perturbing the permeability of the phospholipid bilayer. Since the major obstacle for developing retinoids is their potential cytotoxicity, a selected candidate was further investigated to evaluate its activity on a panel of human cell lines. The compound was found to be well tolerated, with IC50 5-15-fold higher than the MIC on S. aureus strains. Furthermore, the adarotene analogue had a good pharmacokinetic profile, reaching a plasma concentration of about 6 µM after 0.5 h after administration (150 mg/kg), at least twice the MIC observed against various bacterial strains. Moreover, it was demonstrated that the compound potentiated the growth-inhibitory effect of the poorly bioavailable rifaximin, when used in combination. Overall, the collected data pave the way for the development of synthetic retinoids as potential therapeutics for hard-to-treat infectious diseases caused by antibiotic-resistant Gram-positive pathogens.

Ripretinib inhibits HIV-1 transcription through modulation of PI3K-AKT-mTOR.

Despite the effectiveness of antiretroviral therapy (ART) in prolonging the lifespan of individuals infected with HIV-1, it does not offer a cure for acquired immunodeficiency syndrome (AIDS). The "block and lock" approach aims to maintain the provirus in a state of extended transcriptional arrest. By employing the "block and lock" strategy, researchers endeavor to impede disease progression by preventing viral rebound for an extended duration following patient stops receiving ART. The crux of this strategy lies in the utilization of latency-promoting agents (LPAs) that are suitable for impeding HIV-1 provirus transcription. However, previously documented LPAs exhibited limited efficacy in primary cells or samples obtained from patients, underscoring the significance of identifying novel LPAs that yield substantial outcomes. In this study, we performed high-throughput screening of FDA-approved compound library in the J-Lat A2 cell line to discover more efficacious LPAs. We discovered ripretinib being an LPA candidate, which was validated and observed to hinder proviral activation in cell models harboring latent infections, as well as CD4+ T cells derived from infected patients. We demonstrated that ripretinib effectively impeded proviral activation through inhibition of the PI3K-AKT-mTOR signaling pathway in the HIV-1 latent cells, thereby suppressing the opening states of cellular chromatin. The results of this research offer a promising drug candidate for the implementation of the "block and lock" strategy in the pursuit of an HIV-1 cure.

Retinoids in the treatment of photoageing: A histological study of topical retinoid efficacy in black skin.

BACKGROUND: Photoageing describes complex cutaneous changes that occur due to chronic exposure to solar ultraviolet radiation (UVR). The 'gold standard' for the treatment of photoaged white skin is all-trans retinoic acid (ATRA); however, cosmetic retinol (ROL) has also proven efficacious. Recent work has identified that black skin is susceptible to photoageing, characterized by disintegration of fibrillin-rich microfibrils (FRMs) at the dermal-epidermal junction (DEJ). However, the impact of topical retinoids for repair of black skin has not been well investigated. OBJECTIVES: To determine the potential of retinoids to repair photoaged black skin. METHODS: An exploratory intervention study was performed using an in vivo, short-term patch test protocol. Healthy but photoaged black volunteers (>45 years) were recruited to the study, and participant extensor forearms were occluded with either 0.025% ATRA (n = 6; 4-day application due to irritancy) or ROL (12-day treatment protocol for a cosmetic) at concentrations of 0.3% (n = 6) or 1% (n = 6). Punch biopsies from occluded but untreated control sites and retinoid-treated sites were processed for histological analyses of epidermal characteristics, melanin distribution and dermal remodelling. RESULTS: Treatment with ATRA and ROL induced significant acanthosis (all p < 0.001) accompanied by a significant increase in keratinocyte proliferation (Ki67; all p < 0.01), dispersal of epidermal melanin and restoration of the FRMs at the DEJ (all p < 0.01), compared to untreated control. CONCLUSIONS: This study confirms that topical ATRA has utility for the repair of photoaged black skin and that ROL induces comparable effects on epidermal and dermal remodelling, albeit over a longer timeframe. The effects of topical retinoids on black photoaged skin are similar to those reported for white photoaged skin and suggest conserved biology in relation to repair of UVR-induced damage. Further investigation of topical retinoid efficacy in daily use is warranted for black skin.

All-trans retinoic acid exhibits anti-proliferative and differentiating activity in Merkel cell carcinoma cells via retinoid pathway modulation.

BACKGROUND: The limited therapies available for treating Merkel cell carcinoma (MCC), a highly aggressive skin neoplasm, still pose clinical challenges, and novel treatments are required. Targeting retinoid signalling with retinoids, such as all-trans retinoic acid (ATRA), is a promising and clinically useful antitumor approach. ATRA drives tumour cell differentiation by modulating retinoid signalling, leading to anti-proliferative and pro-apoptotic effects. Although retinoid signalling is dysregulated in MCC, ATRA activity in this tumour is unknown. This study aimed to evaluate the impact of ATRA on the pathological phenotype of MCC cells. METHODS: The effect of ATRA was tested in various Merkel cell polyomavirus-positive and polyomavirus-negative MCC cell lines in terms of cell proliferation, viability, migration and clonogenic abilities. In addition, cell cycle, apoptosis/cell death and the retinoid gene signature were evaluated upon ATRA treatments. RESULTS: ATRA efficiently impaired MCC cell proliferation and viability in MCC cells. A strong effect in reducing cell migration and clonogenicity was determined in ATRA-treated cells. Moreover, ATRA resulted as strongly effective in arresting cell cycle and inducing apoptosis/cell death in all tested MCC cells. Enrichment analyses indicated that ATRA was effective in modulating the retinoid gene signature in MCC cells to promote cell differentiation pathways, which led to anti-proliferative and pro-apoptotic/cell death effects. CONCLUSIONS: These results underline the potential of retinoid-based therapy for MCC management and might open the way to novel experimental approaches with other retinoids and/or combinatorial treatments.

Developmental exposure to pesticides that disrupt retinoic acid signaling causes persistent retinoid and behavioral dysfunction in zebrafish.

Early developmental exposure to environmental toxicants may play a role in the risk for developing autism. A variety of pesticides have direct effects on retinoic acid (RA) signaling and as RA signaling has important roles in neurodevelopment, such compounds may cause developmental neurotoxicity through an overlapping adverse outcome pathway. It is hypothesized that a pesticide's embryonic effects on retinoid function may correspond with neurobehavioral disruption later in development. In the current studies, we determined the effects of RA-acting pesticides on neurobehavioral development in zebrafish. Buprofezin and imazalil caused generalized hypoactivity in the larval motility test, whereas chlorothalonil and endosulfan I led to selective hypoactivity and hyperactivity, respectively. With buprofezin, chlorothalonil, and imazalil, hypoactivity and/or novel anxiety-like behaviors persisted in adulthood and buprofezin additionally decreased social attraction responses in adulthood. Endosulfan I did not produce significant adult behavioral effects. Using qPCR analyses of adult brain tissue, we observed treatment-induced alterations in RA synthesis or catabolic genes, indicating persistent changes in RA homeostasis. These changes were compound-specific, with respect to expression directionality, and potential patterns of homeostatic disruption. Results suggest the likely persistence of disruptions in RA signaling well into adulthood and may represent compensatory mechanisms following early life stage exposures. This study demonstrates that early developmental exposure to environmental toxicants that interfere with RA signaling causes short as well as long-term behavioral disruption in a well-established zebrafish behavioral model and expand upon the meaning of the RA adverse outcome pathway, indicating that observed effects likely correspond with the nature of underlying homeostatic effects.

A retinoid analogue, TTNPB, promotes clonal expansion of human pluripotent stem cells by upregulating CLDN2 and HoxA1.

Enzymatic dissociation of human pluripotent stem cells (hPSCs) into single cells during routine passage leads to massive cell death. Although the Rho-associated protein kinase inhibitor, Y-27632 can enhance hPSC survival and proliferation at high seeding density, dissociated single cells undergo apoptosis at clonal density. This presents a major hurdle when deriving genetically modified hPSC lines since transfection and genome editing efficiencies are not satisfactory. As a result, colonies tend to contain heterogeneous mixtures of both modified and unmodified cells, making it difficult to isolate the desired clone buried within the colony. In this study, we report improved clonal expansion of hPSCs using a retinoic acid analogue, TTNPB. When combined with Y-27632, TTNPB synergistically increased hPSC cloning efficiency by more than 2 orders of magnitude (0.2% to 20%), whereas TTNPB itself increased more than double cell number expansion compared to Y-27632. Furthermore, TTNPB-treated cells showed two times higher aggregate formation and cell proliferation compared to Y-27632 in suspension culture. TTNPB-treated cells displayed a normal karyotype, pluripotency and were able to stochastically differentiate into all three germ layers both in vitro and in vivo. TTNBP acts, in part, by promoting cellular adhesion and self-renewal through the upregulation of Claudin 2 and HoxA1. By promoting clonal expansion, TTNPB provides a new approach for isolating and expanding pure hPSCs for future cell therapy applications.

Retinoids and EZH2 inhibitors cooperate to orchestrate anti-oncogenic effects on bladder cancer cells.

The highly mutated nature of bladder cancers harboring mutations in chromatin regulatory genes opposing Polycomb-mediated repression highlights the importance of targeting EZH2 in bladder cancer. Furthermore, the critical role of the retinoic acid signaling pathway in the development and homeostasis of the urothelium, and the anti-oncogenic effects of retinoids are well established. Therefore, our aim is to simultaneously target EZH2 and retinoic acid signaling in bladder cancer to potentiate the therapeutic response. Here we report that this coordinated targeting strategy stimulates an anti-oncogenic profile, as reflected by inducing a synergistic reduction in cell viability that was associated with increased apoptosis and cell cycle arrest in a cooperative and orchestrated manner. This study characterized anti-oncogenic transcriptional reprogramming centered on the transcriptional regulator CHOP by stimulating the endoplasmic reticulum stress response. We further portrayed a molecular mechanism whereby EZH2 maintains H3K27me3-mediated repression of a subset of genes involved in unfolded protein responses, reflecting the molecular mechanism underlying this co-targeting strategy. These findings highlight the importance of co-targeting the EZH2 and retinoic acid pathway in bladder cancers and encourage the design of novel treatments employing retinoids coupled with EZH2 inhibitors in bladder carcinoma.

Synergistic effect of chitosan and ß-carotene in inhibiting MNU-induced retinitis pigmentosa.

In this study, N-Methyl-N-nitrosourea (MNU) was intraperitoneally injected to construct a mouse retinitis pigmentosa (RP) model to evaluate the protective effect of chitosan and ß-carotene on RP. The results demonstrated that chitosan synergized with ß-carotene significantly reduced retinal histopathological structural damage in RP mice. The co-treatment group of ß-carotene and chitosan restored the retinal thickness and outer nuclear layer thickness better than the group treated with the two alone, and the thickness reached the normal level. The content of ß-carotene and retinoids in the liver of chitosan and ß-carotene co-treated group increased by 46.75 % and 20.69 %, respectively, compared to the ß-carotene group. Chitosan and ß-carotene supplement suppressed the expressions of Bax, Calpain2, Caspase3, NF-κB, TNF-α, IL-6, and IL-1ß, and promoted the up-regulation of Bcl2. Chitosan and ß-carotene interventions remarkably contributed to the content of SCFAs and enhanced the abundance of Ruminococcaceae, Rikenellaceae, Odoribacteraceae and Helicobacteraceae. Correlation analysis demonstrated a strong association between gut microbiota and improvement in retinitis pigmentosa. This study will provide a reference for the study of the gut-eye axis.

Endoplasmic reticulum stress as a target for retinoids in cancer treatment.

Retinoids, natural and synthetic derivatives of vitamin A, have various regulatory activities including controlling cellular proliferation, differentiation, and death. Furthermore, they have been used to treat specific cancers with satisfying results. Nevertheless, retinoids have yet to be converted into effective systemic therapies for the majority of tumor types. Regulation of unfolded protein response signaling, and persistent activation of endoplasmic reticulum stress (ER-stress) are promising treatment methods for cancer. The present article reviews the current understanding of how vitamin A and its derivatives may aid to cause ER-stress-activated apoptosis, as well as therapeutic options for exploiting ER-stress for achieving beneficial goal. The therapeutic use of some retinoids discussed in this article was related to decreased disease recurrence and improved therapeutic outcomes via ER-stress activation and promotion, indicating that retinoids may play an important role in cancer treatment and prevention. More research is needed to expand the use of vitamin A derivatives in cancer therapy, either alone or in combination with unfolded protein response inducers.

IRX4204 Induces Senescence and Cell Death in HER2-positive Breast Cancer and Synergizes with Anti-HER2 Therapy.

PURPOSE: Rexinoids, agonists of nuclear retinoid X receptor (RXR), have been used for the treatment of cancers and are well tolerated in both animals and humans. However, the usefulness of rexinoids in treatment of breast cancer remains unknown. This study examines the efficacy of IRX4204, a highly specific rexinoid, in breast cancer cell lines and preclinical models to identify a biomarker for response and potential mechanism of action. EXPERIMENTAL DESIGN: IRX4204 effects on breast cancer cell growth and viability were determined using cell lines, syngeneic mouse models, and primary patient-derived xenograft (PDX) tumors. In vitro assays of cell cycle, apoptosis, senescence, and lipid metabolism were used to uncover a potential mechanism of action. Standard anti-HER2 therapies were screened in combination with IRX4204 on a panel of breast cancer cell lines to determine drug synergy. RESULTS: IRX4204 significantly inhibits the growth of HER2-positive breast cancer cell lines, including trastuzumab and lapatinib-resistant JIMT-1 and HCC1954. Treatment with IRX4204 reduced tumor growth rate in the MMTV-ErbB2 mouse and HER2-positive PDX model by 49% and 44%, respectively. Mechanistic studies revealed IRX4204 modulates lipid metabolism and induces senescence of HER2-positive cells. In addition, IRX4204 demonstrates additivity and synergy with HER2-targeted mAbs, tyrosine kinase inhibitors, and antibody-drug conjugates. CONCLUSIONS: These findings identify HER2 as a biomarker for IRX4204 treatment response and demonstrate a novel use of RXR agonists to synergize with current anti-HER2 therapies. Furthermore, our results suggest that RXR agonists can be useful for the treatment of anti-HER2 resistant and metastatic HER2-positive breast cancer.

Rosiglitazone and trametinib exhibit potent anti-tumor activity in a mouse model of muscle invasive bladder cancer.

Muscle invasive bladder cancers (BCs) can be divided into 2 major subgroups-basal/squamous (BASQ) tumors and luminal tumors. Since Pparg has low or undetectable expression in BASQ tumors, we tested the effects of rosiglitazone, Pparg agonist, in a mouse model of BASQ BC. We find that rosiglitazone reduces proliferation while treatment with rosiglitazone plus trametinib, a MEK inhibitor, induces apoptosis and reduces tumor volume by 91% after 1 month. Rosiglitazone and trametinib also induce a shift from BASQ to luminal differentiation in tumors, which our analysis suggests is mediated by retinoid signaling, a pathway known to drive the luminal differentiation program. Our data suggest that rosiglitazone, trametinib, and retinoids, which are all FDA approved, may be clinically active in BASQ tumors in patients.

ROS play an important role in ATPR inducing differentiation and inhibiting proliferation of leukemia cells by regulating the PTEN/PI3K/AKT signaling pathway

BACKGROUND: Acute myeloid leukemia (AML) is an aggressive and mostly incurable hematological malignancy with frequent relapses after an initial response to standard chemotherapy. Therefore, novel therapies are urgently required to improve AML clinical outcomes. 4-Amino-2-trifluoromethyl-phenyl retinate (ATPR), a novel all-trans retinoic acid (ATRA) derivative designed and synthesized by our team, has been proven to show biological anti-tumor characteristics in our previous studies. However, its potential effect on leukemia remains unknown. The present research aims to investigate the underlying mechanism of treating leukemia with ATPR in vitro. METHODS: In this study, the AML cell lines NB4 and THP-1 were treated with ATPR. Cell proliferation was analyzed by the CCK-8 assay. Flow cytometry was used to measure the cell cycle distribution and cell differentiation. The expression levels of cell cycle and differentiation-related proteins were detected by western blotting and immunofluorescence staining. The NBT reduction assay was used to detect cell differentiation. RESULTS: ATPR inhibited cell proliferation, induced cell differentiation and arrested the cell cycle at the G0/G1 phase. Moreover, ATPR treatment induced a time-dependent release of reactive oxygen species (ROS). Additionally, the PTEN/PI3K/Akt pathway was downregulated 24 h after ATPR treatment, which might account for the anti-AML effects of ATPR that result from the ROS-mediated regulation of the PTEN/PI3K/AKT signaling pathway. CONCLUSIONS: Our observations could help to develop new drugs targeting the ROS/PTEN/PI3K/Akt pathway for the treatment of AML.

Abordagem cirúrgica de faixas constritivas em Síndrome de Vohwinkel / Surgical correction of constrictive bands in Vohwinkel syndrome

A Síndrome de Vohwinkel ou ceratodermia hereditária mutilante é uma ceratodermia palmoplantar rara, que se manifesta na infância e se torna mais evidente nas fases de adolescência e idade adulta. Doença de herança preferencialmente autossômica dominante, acomete mais mulheres e caucasianos. A hiperceratose palmoplantar difusa, com aparência de favo de mel; as faixas constritivas digitais conhecidas como pseudoainhum, e as placas ceratósicas em forma de estrela-do-mar no dorso de mãos e pés, podendo acometer cotovelos e joelhos, são os achados clínicos característicos da Síndrome. O presente trabalho trata de um relato de caso de uma paciente com Síndrome de Vohwinkel e a terapêutica cirúrgica realizada nas faixas constritivas.

Vohwinkel syndrome, also known as hereditary mutilating keratoderma, is a rare palmoplantar keratoderma that manifests in childhood and becomes more evident in adolescence and adulthood. This preferential autosomal dominant disease affects more women and Caucasians. Its clinical features are diffuse palmoplantar keratoderma with the appearance of honeycomblike constricting rings in the fingers and toes known as pseudo-ainhum, and starfish-shaped keratotic plaques on the dorsal aspect of the hands and feet that can affect the elbows and knees. The present report describes a case report of a patient with Vohwinkel syndrome and surgical correction of the constrictive bands.

Use of retinoids in the treatment of oral leukoplakia: a review / Uso de retinoides no tratamento de leucoplasias bucais: revisão

OBJECTIVE: The purpose of this paper is to review the literature regarding the topical use of the retinoids in the treatment of oral leukoplakia, discussing their mechanisms of action, indications, effectiveness, and adverse effects. DISCUSSION: Leukoplakia is defined as white lesion in oral mucous membrane that cannot be characterized as any other entity and it has potential for malignancy. It does not present specific histological pattern. Due to its potential for malignancy and high prevalence, dentists should know how to diagnose and treat it correctly. The retinoids are chemopreventive agents derived from the vitamin A. They could be either natural or synthetic and their main role is to suppress cellular mitosis. Retinoid derivatives have been used as agents for chemoprevention of malignant transformation of leukoplakias due to its potential effect on the control of the differentiation and proliferation of the epithelial cells, as well as their induction of apoptosis. CONCLUSION: The topical use of retinoids to treat oral leukoplakia is safe, convenient and effective, with minor side effects than the systemic administration.

OBJETIVO: A proposta deste artigo é revisar a literatura referente ao uso de retinoides no tratamento de lecoplasiasbucais e discutir o mecanismo de ação, indicações, efetividade e efeitos adversos. DISCUSSÃO: Leucoplasia é definida como lesão branca na mucosa bucal que não pode ser caracterizada como qualquer outra entidade e tem potencial de malignização. Não apresenta padrão histológico específico e, por causa de seu potencial de malignização e alta prevalência, os cirurgiões-dentistas devem conhecer como diagnosticá-la e tratá-la corretamente. Os retinoidestêm sido usados como agentes quimio-profiláticos para a transformação maligna das leucoplasias por seu efeito potencial no controle da diferenciação e proliferação da células epiteliais, bem como capazes de indução de apoptose. CONCLUSÃO: O uso tópico de retinoides para tratar leucoplasias é seguro, conveniente e efetivo, com efeitos colaterais menores do que na administração sistêmica.

Retonoides, avances farmacológicos: isotretinoína / Retonoids, advances in pharmacology: isotretinoin

Se presenta una actualización farmacológica y terapéutica de la isotretinoína sobre la base de la experiencia clínica nacional e internacional acumulada hasta la fecha. Integrante de la familia química de los retonoides, la isotretinoína permite obtener remisiones significativas en la acné severa, particularmente noduloquística y conglobata. Para su correcto manejo clínico se recomienda seguir el esquema posológico, observar cuidadosamente las contraindicaciones, precauciones y advertencias, dado su potencial teratogénico, y manejar las reacciones adversas para no desalentar al paciente al comienzo del tratamiento y evitar una pérdida del efecto terapéutico a largo plazo.

Desarrollo de los retinoides en investigación básica y clinica en oncología: conceptos actuales / The development of retinoids in basic research and clinics in oncology: current concepts

Después de mencionar brevemente algunos conceptos generales sobre el cáncer, se revisan los conceptos farmacológicos principales de los retinoides, (compuestos que comprenden a la vitamina A y a sus análogos naturales y sintéticos), así como los estudios epidemiológicos y mecanísmos de acción probables en cuanto al efecto anticancerígeno de estos compuestos. Después, se analiza la acción de ellos sobre neoplasias no cancerosas, enfermedades premalignas y cáncer de los aparatos digestivo, respiratorio, urinario, reproductor, locomotor y circulatorio, así como sobre el sistema nervioso central, órganos de los sentidos, tejidos blandos y, especialmente, de la piel y sus anexos. Se concluye que los retinoides han probado poseer acción contra las neoplasias malignas, probablemente por sus efectos sobre la proliferacción y diferenciacción celulares y que las indicaciones primordiales en ellos en el campo de la oncología las constituyen la prevención de neoplasias malignas en sujeitos de alto riesgo y el tratamiento de tumores malignos en fases iniciales (en combinacción con la modalidades terapéuticas clásicas y, sobre todo, cuando se descubre inmunosupresión), siendo el futuro muy promisorio en este aspecto de investigacción a la medicina

Bases para el uso combinado de los interferones y de los retinoides en oncología clínica / Basis for the combined use of interferon and retinoid in clinical oncology

El acido retinoico y el interferón alfa tienen actividad limitada en el tratamiento de cáncer avanzado. La información obtenida de los cultivos celulares indican que, en combinación, estos agentes tienen incremento de la actividad biológica modulando el crecimiento y la diferenciación en un número de tipos celulares malignos. Trabajos clínicos recientes sobre el tratamiento de algunos carcinomas avanzados de células escamosas informan actividad terapéutica con este régimen. Este artículo revisa los datos preclínicos obtenidos al evaluar el ácido retinoico en combinación con interferones

La prevención química del cáncer / The chemoprevention of cancer

El objetivo de este trabajo fue evaluar el concepto, la situación actual y las perspectivas en la prevención química del cáncer. Para dicho análisis se consideraron los mecanismos involucrados en el proceso, las características que requieren los compuestos para ubicarlos en estudios preclínicos y clínicos, y el estado actual en que se encuentran agentes como los retinoides, carotenoides, calcio, ácido alérgico y fumárico, curcumino y aspirina. La información sugiere que la estrategia planteada tiene bases sólidas y que en un futuro cercano se verán efectos positivos en el hombre