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Messenger RNA (mRNA) cancer vaccines are a new class of immunotherapies that can activate the immune system to recognize and destroy cancer cells. However, their effectiveness in treating colorectal cancer located on the mucosal surface of the gut is limited due to the insufficient activation of mucosal immune response and inadequate infiltration of cytotoxic T cells into tumors. To address this issue, a new mRNA cancer vaccine is developed that can stimulate mucosal immune responses in the gut by co‐delivering all‐trans‐retinoic acid (ATRA) and mRNA using lipid nanoparticle (LNP). The incorporation of ATRA has not only improved the mRNA transfection efficiency of LNP but also induced high expression of gut‐homing receptors on vaccine‐activated T cells. Additionally, the use of LNP improves the aqueous solubility of ATRA, eliminating the need for toxic solvents to administer ATRA. Upon intramuscular injections, ATRA‐adjuvanted mRNA‐LNP significantly increase the infiltration of antigen‐specific, cytotoxic T cells in the lamina propria of the intestine, mesenteric lymph nodes, and orthotopic colorectal tumors, resulting in significantly improved tumor inhibition and prolonged animal survival compared to conventional mRNA‐LNP without ATRA. Overall, this study provides a promising approach for improving the therapeutic efficacy of mRNA cancer vaccines against colorectal cancer. [ABSTRACT FROM AUTHOR]

ABSTRACT Background Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia defined by a fusion gene transcript called PML::RARA. Pseudotumor cerebri (PTC) is characterized by elevated intracranial pressure (ICP) and presents with pulsatile tinnitus, headaches, and visual disturbances. Pseudotumor cerebri has been observed in some patients undergoing long‐term ATRA therapy. While both APL and PTC have been individually described in the literature, their coexistence in a single patient, especially with PTC being the first clinical manifestation of APL, is an exceptionally rare occurrence, making this case particularly unique and warranting further investigation. Case Presentation We present the case of a 30‐year‐old woman who initially presented with symptoms suggestive of PTC. The diagnosis of PTC was confirmed through a lumbar puncture. However, further investigations revealed that the patient had APL, which is typically sensitive to treatment with all‐trans‐retinoic acid (ATRA). To our knowledge, the association between APL and PTC as the first clinical manifestation of APL in adult patients has not been previously reported in the literature, further highlighting the exceptional rarity of this case. Conclusions This case underscores the importance of considering underlying systemic diseases in patients presenting with PTC, as it may represent an exceptionally rare initial manifestation of a rare underlying malignancy such as APL. The coexistence of APL and PTC in this patient highlights the need for a comprehensive evaluation and management approach to promptly diagnose and treat coexisting conditions. Healthcare providers must be aware of this association and consider the possibility of APL when evaluating patients with PTC symptoms. Such awareness can prompt timely recognition and appropriate management, thereby improving patient outcomes and preventing potential delays in diagnosis and treatment.

Abstract Background Breast cancer (BC) is the most commonly diagnosed cancer in women. Treatment approaches that differ between estrogen-positive (ER+) and triple-negative BC cells (TNBCs) and may subsequently affect cancer biomarkers, such as H19 and telomerase, are an emanating delight in BC research. For instance, all-trans-Retinoic acid (ATRA) could represent a potent regulator of these oncogenes, regulating microRNAs, mostly let-7a microRNA (miR-let-7a), which targets the glycolysis pathway, mainly pyruvate kinase M2 (PKM2) and lactate dehydrogenase A (LDHA) enzymes. Here, we investigated the potential role of ATRA in H19, telomerase, miR-let-7a, and glycolytic enzymes modulation in ER + and TNBC cells. Methods MCF-7 and MDA-MB-231 cells were treated with 5 µM ATRA and/or 100 nM fulvestrant. Then, ATRA-treated or control MCF-7 cells were transfected with either H19 or hTERT siRNA. Afterward, ATRA-treated or untreated MDA-MB-231 cells were transfected with estrogen receptor alpha ER(α) or beta ER(β) expression plasmids. RNA expression was evaluated by RT‒qPCR, and proteins were assessed by Western blot. PKM2 activity was measured using an NADH/LDH coupled enzymatic assay, and telomerase activity was evaluated with a quantitative telomeric repeat amplification protocol assay. Student’s t-test or one-way ANOVA was used to analyze data from replicates. Results Our results showed that MCF-7 cells were more responsive to ATRA than MDA-MB-231 cells. In MCF-7 cells, ATRA and/or fulvestrant decreased ER(α), H19, telomerase, PKM2, and LDHA, whereas ER(β) and miR-let-7a increased. H19 or hTERT knockdown with or without ATRA treatment showed similar results to those obtained after ATRA treatment, and a potential interconnection between H19 and hTERT was found. However, in MDA-MB-231 cells, RNA expression of the aforementioned genes was modulated after ATRA and/or fulvestrant, with no significant effect on protein and activity levels. Overexpression of ER(α) or ER(β) in MDA-MB-231 cells induced telomerase activity, PKM2 and LDHA expression, in which ATRA treatment combined with plasmid transfection decreased glycolytic enzyme expression. Conclusions To the best of our knowledge, our study is the first to elucidate a new potential interaction between the estrogen receptor and glycolytic enzymes in ER + BC cells through miR-let-7a.

Background: Breast cancer (BC) is the most commonly diagnosed cancer in women. Treatment approaches that differ between estrogen-positive (ER+) and triple-negative BC cells (TNBCs) and may subsequently affect cancer biomarkers, such as H19 and telomerase, are an emanating delight in BC research. For instance, all-trans-Retinoic acid (ATRA) could represent a potent regulator of these oncogenes, regulating microRNAs, mostly let-7a microRNA (miR-let-7a), which targets the glycolysis pathway, mainly pyruvate kinase M2 (PKM2) and lactate dehydrogenase A (LDHA) enzymes. Here, we investigated the potential role of ATRA in H19, telomerase, miR-let-7a, and glycolytic enzymes modulation in ER + and TNBC cells. Methods: MCF-7 and MDA-MB-231 cells were treated with 5 µM ATRA and/or 100 nM fulvestrant. Then, ATRA-treated or control MCF-7 cells were transfected with either H19 or hTERT siRNA. Afterward, ATRA-treated or untreated MDA-MB-231 cells were transfected with estrogen receptor alpha ER(α) or beta ER(β) expression plasmids. RNA expression was evaluated by RT‒qPCR, and proteins were assessed by Western blot. PKM2 activity was measured using an NADH/LDH coupled enzymatic assay, and telomerase activity was evaluated with a quantitative telomeric repeat amplification protocol assay. Student's t-test or one-way ANOVA was used to analyze data from replicates. Results: Our results showed that MCF-7 cells were more responsive to ATRA than MDA-MB-231 cells. In MCF-7 cells, ATRA and/or fulvestrant decreased ER(α), H19, telomerase, PKM2, and LDHA, whereas ER(β) and miR-let-7a increased. H19 or hTERT knockdown with or without ATRA treatment showed similar results to those obtained after ATRA treatment, and a potential interconnection between H19 and hTERT was found. However, in MDA-MB-231 cells, RNA expression of the aforementioned genes was modulated after ATRA and/or fulvestrant, with no significant effect on protein and activity levels. Overexpression of ER(α) or ER(β) in MDA-MB-231 cells induced telomerase activity, PKM2 and LDHA expression, in which ATRA treatment combined with plasmid transfection decreased glycolytic enzyme expression. Conclusions: To the best of our knowledge, our study is the first to elucidate a new potential interaction between the estrogen receptor and glycolytic enzymes in ER + BC cells through miR-let-7a. [ABSTRACT FROM AUTHOR]

Combining new therapeutics with all-trans-retinoic acid (ATRA) could improve the efficiency of acute myeloid leukemia (AML) treatment. Modeling the process of ATRA-induced differentiation based on the transcriptomic profile of leukemic cells resulted in the identification of key targets that can be used to increase the therapeutic effect of ATRA. The genome-scale transcriptome analysis revealed the early molecular response to the ATRA treatment of HL-60 cells. In this study, we performed the transcriptomic profiling of HL-60, NB4, and K562 cells exposed to ATRA for 3–72 h. After treatment with ATRA for 3, 12, 24, and 72 h, we found 222, 391, 359, and 1032 differentially expressed genes (DEGs) in HL-60 cells, as well as 641, 1037, 1011, and 1499 DEGs in NB4 cells. We also found 538 and 119 DEGs in K562 cells treated with ATRA for 24 h and 72 h, respectively. Based on experimental transcriptomic data, we performed hierarchical modeling and determined cyclin-dependent kinase 6 (CDK6), tumor necrosis factor alpha (TNF-alpha), and transcriptional repressor CUX1 as the key regulators of the molecular response to the ATRA treatment in HL-60, NB4, and K562 cell lines, respectively. Mapping the data of TMT-based mass-spectrometric profiling on the modeling schemes, we determined CDK6 expression at the proteome level and its down-regulation at the transcriptome and proteome levels in cells treated with ATRA for 72 h. The combination of therapy with a CDK6 inhibitor (palbociclib) and ATRA (tretinoin) could be an alternative approach for the treatment of acute myeloid leukemia (AML). [ABSTRACT FROM AUTHOR]

Objective: This study attempts to modify Polylactic Acid (PLA) with the natural polymer Collagen (Coll), to develop materials such as an electrospun scaffold that have better mechanical stability and biocompatibility. Retinoic acid (RA), a bioactive material that promotes nerve growth, is to be added to the nanofiber scaffolds as part of this project. Methods: One of the most important methods we employed in this work to create nanofibrous scaffolds was electrospinning. Results: The synthesized nanofiber scaffold exhibited a diameter of 255 ± 40 nm and a tensile strength of 175 ± 10.4 N, providing sufficient support for native peripheral nerve repair. The inclusion of Coll enhanced the scaffold's hydrophilic behavior (contact angle: 56 ± 4°), ensuring stability in aqueous solutions. In addition, cell adhesion and proliferation are demonstrated to be improved by PLA composite nanofibers based on Collagen, while PC12 cell adhesion and proliferation are further improved by RA. Conclusion: Based on their biodegradability, robust mechanical properties, and porous structure, these scaffolds are excellent choices for nerve tissue engineering, according to our findings. The significant increase in PC12 cells' adhesion and proliferation upon the addition of RA demonstrates the cells' potential for nerve repair. [ABSTRACT FROM AUTHOR]

All-trans retinoic acid (ATRA) is a vitamin A derivative which can increase intracranial pressure, causing visual loss and papilledema. Those patients should be treated similarly to others patients with idiopathic intracranial hypertension. We described a case of a 32-year-old woman presenting with severe visual loss and intracranial hypertension induced by ATRA for acute promyelocytic leukemia, which was treated clinically and with optic nerve sheath fenestration. Patients receiving ATRA therapy should be monitored to neurological and ophthalmic signs and symptoms of intracranial hypertension.

Acute promyelocytic leukemia (APL) is a rare and aggressive form of acute myeloid leukemia (AML). Instead of cytotoxic chemotherapy, a combination of all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO) represents front-line therapy in low-risk patients. However, the therapeutic approach could be challenging in the case of a concomitant diagnosis of Brugada syndrome (BrS), a genetic disease characterized by an increased risk of arrhythmias and sudden cardiac death. Here, we present the case of a BrS patient who has been diagnosed with low-risk APL and treated with ATRA and ATO without observing arrhythmic events. In particular, we highlight the difficulties encountered by clinicians during the diagnostic work-up and the choice of the best treatment for these patients.

Cataloging human proteins and evaluation of their expression, cellular localization, functions, and potential medical significance are important tasks for the global proteomic community. At present, localization and functions of protein products for almost half of protein-coding genes remain unknown or poorly understood. Investigation of organelle proteomes is a promising approach to uncovering localization and functions of human proteins. Nuclear proteome is of particular interest because many nuclear proteins, e.g., transcription factors, regulate functions that determine cell fate. Meta-analysis of the nuclear proteome, or nucleome, of HL-60 cells treated with all-trans-retinoic acid (ATRA) has shown that the functions and localization of a protein product of the SOWAHD gene are poorly understood. Also, there is no comprehensive information on the SOWAHD gene expression at the protein level. In HL-60 cells, the number of mRNA transcripts of the SOWAHD gene was determined as 6.4 ± 0.7 transcripts per million molecules. Using targeted mass spectrometry, the content of the SOWAHD protein was measured as 0.27 to 1.25 fmol/μg total protein. The half-life for the protein product of the SOWAHD gene determined using stable isotope pulse-chase labeling was ~19 h. Proteomic profiling of the nuclear fraction of HL-60 cells showed that the content of the SOWAHD protein increased during the ATRA-induced granulocytic differentiation, reached the peak value at 9 h after ATRA addition, and then decreased. Nuclear location and involvement of the SOWAHD protein in the ATRA-induced granulocytic differentiation have been demonstrated for the first time. [ABSTRACT FROM AUTHOR]

Acute promyelocytic leukemia (APL) is a rare and aggressive form of acute myeloid leukemia (AML). Instead of cytotoxic chemotherapy, a combination of all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO) represents front-line therapy in low-risk patients. However, the therapeutic approach could be challenging in the case of a concomitant diagnosis of Brugada syndrome (BrS), a genetic disease characterized by an increased risk of arrhythmias and sudden cardiac death. Here, we present the case of a BrS patient who has been diagnosed with low-risk APL and treated with ATRA and ATO without observing arrhythmic events. In particular, we highlight the difficulties encountered by clinicians during the diagnostic work-up and the choice of the best treatment for these patients. [ABSTRACT FROM AUTHOR]

Vitamin A and its synthetic analogues are used in the treatment of numerous skin diseases. The main genomic effects of the natural form of vitamin A (retinol palmitate) are associated with its active metabolite all-trans-retinoic acid and are compensated by several restrictive mechanisms. Numerous studies have proved that retinol stimulates the proliferation of keratinocytes of the basal layer of the epidermis and endothelial cells, and also activates dermal fibroblasts to synthesize proteins of the extracellular matrix of the dermis. As a result, the thickening the epidermis, increases the mechanical strength of the skin and the hydrating ability of the dermis, angiogenesis increase. The ability of retinol to enhance the adhesion of endothelial cells and leukocytes, regulate the processes of keratinization and sebum secretion was found. Vitamin A is also a powerful antioxidant. Retinol palmitate is used as the main or auxiliary drug for the treatment of a wide range of dermatoses. The principle of application is based on clinical studies and confirmed by existing experimental data. In the treatment, the following algorithm is followed. If retinol palmitate is necessary to improve epithelialization and strengthen the epidermal barrier, medium therapeutic doses should be used. For the treatment of disorders of keratinization processes, depending on the severity of the pathological condition, medium and high therapeutic doses of the drug are used. Violation of the processes of sebum secretion and severe hyperkeratosis respond better to treatment at high therapeutic doses. It should be noted that many skins clinical manifestations mostly regress under the action of vitamin A in doses that do not lead to the appearance of signs of toxicity of the drug.

The zebrafish embryotoxicity test (ZET) is widely used in developmental toxicology. The analysis of gene expression regulation in ZET after chemical exposure provides mechanistic information about the effects of chemicals on morphogenesis in the test. The gene expression response magnitude has been shown to change with exposure duration. The objective of this work is to study the effect of the exposure duration on the magnitude of gene expression changes in the all-trans retinoic acid (ATRA) signaling pathway in the ZET. Retinoic acid regulation is a key driver of morphogenesis and is therefore employed here as an indicator for the regulation of developmental genes. A teratogenic concentration of 7.5 nM of ATRA was given at 3 hrs post fertilization (hpf) for a range of exposure durations until 120 hrs of development. The expression of a selection of genes related to ATRA signaling and downstream developmental genes was determined. The highest magnitudes of gene expression regulation were observed after 2–24 hrs exposure with an optimal response after 4 hrs. Longer exposures showed a decrease in the gene expression response, although continued exposure to 120 hpf caused malformations and lethality. This study shows that assessment of gene expression regulation at early time points after the onset of exposure in the ZET may be optimal for the prediction of developmental toxicity. We believe these results could help optimize sensitivity in future studies with ZET. • ATRA induced duration-dependent gene expression changes in the ZET assay. • Maximal gene expression responses were observed around 4 hrs after exposure. • Early gene expression changes precede the occurrence of malformations. • Timing is important in optimizing ZET assay gene expression readout. [ABSTRACT FROM AUTHOR]

All-trans retinoic acid (RA) is an effective anti-aging chemical substance widely used in skin-care products. RA compromises epidermal differentiation and induces keratinocyte proliferation, causing hyaluronic acid production through mechanisms that are not completely understood. Klotho protein causes the differentiation of human epidermal keratinocytes. Klotho gene expression is mediated by epidermal growth factor (EGF), which inhibits cell apoptosis in aging-related diseases. The klotho gene causes human aging syndrome, including short lifespan, skin atrophy, and osteoporosis. We investigated the relationship between RA and klotho in epidermal keratinocytes for the first time. In human epidermal keratinocytes, RA induced klotho gene expression. Treatment with both RA and recombinant klotho induced hyaluronic acid production in human epidermal keratinocytes. However, in klotho small interfering RNA (siRNA)-transfected keratinocytes, RA produced less hyaluronic acid than in the control group, indicating that RA may partially regulate hyaluronic acid production through a klotho-dependent pathway. Knockdown of klotho gene expression inactivated the EGFR-extracellular signal-regulated kinase (ERK) signaling pathway, which is involved in hyaluronic acid production. We concluded that the effect of RA on hyaluronic acid production is partly regulated through the klotho-mediated EGFR signaling pathway in human epidermal keratinocytes.

Docetaxel (DTX) is a poorly soluble drug. The purpose of this study was to explore a DTX-loaded micelle delivery system using N-(all-trans-retinoyl)-L-cysteic acid methyl ester sodium salt (XMeNa) as the carrier materials. In this study, amphiphilic surfactant XMeNa was synthesized. Then, the blood biocompatibility and the value of critical micelle concentration (CMC) were assessed by a hemolysis test and pyrene-based fluorescent probe techniques, respectively. The XM-DTX micelles were prepared using the method of thin-film hydration, and characterized by dynamic light scattering and transmission electron microscopy (TEM). The entrapment efficiency (EE) and drug loading efficiency (DLE) were assessed by the ultrafiltration method. In vitro release and pharmacokinetic behaviors of XM-DTX micelles were performed in rats using Taxotere (a commercialized DTX injection) as a control. Our data confirmed the excellent blood biocompatibility of XMeNa as a carrier. XMeNa can self-assemble into micelles in aqueous media with a very low CMC (6.2 μg/mL). The average size and zeta potential of the XM-DTX micelles were 17.3 ± 0.2 nm, and −41.6 ± 0.3 mV, respectively. EE and DLE reached up to 95.3 ± 0.7% and 22.4 ± 0.2%, respectively, which may account for the high solubility of DTX in normal saline. The micelles were spherical in TEM with good dispersion and no aggregation and adhesion, and exhibited good stability after reconstitution over 8 hours. Results from in vitro release assay suggested a much slower release behavior of XM-DTX micelles in comparison to Taxotere. Additionally, XM-DTX micelles prolonged DTX retention in blood circulation, increased the area under the curve by 2.4-fold, and significantly decreased the clearance of the drug. Given above, the XM-DTX micelles could improve the solubility and the release of DTX. The amphiphilic surfactant XMeNa also exhibited great potential as a vehicle for exploring delivery of poorly water soluble drugs in the future.

Haimeng Yan,1 Donghua He,1 Weijia Huang,1 Fei Chen,1,2 Jingsong He,1 Zhen Cai,1,3,4 Yi Zhao1 1Bone Marrow Transplantation Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People’s Republic of China; 2Department of Hematology, Haining People’s Hospital, Haining, People’s Republic of China; 3Institute of Hematology, Zhejiang University, Hangzhou, Zhejiang, People’s Republic of China; 4Zhejiang Laboratory for Systems & Precision Medicine, Zhejiang University Medical Center, Hangzhou, 311121, People’s Republic of ChinaCorrespondence: Yi Zhao; Zhen CaiBone Marrow Transplantation Center, Zhejiang University School of Medicine, Qingchun Road 79, Hangzhou, 310009, People’s Republic of ChinaEmail zhaoyi999@zju.edu.cn; caiz@zju.edu.cnBackground: Acute promyelocytic leukemia differentiation syndrome (APL DS) is a common and severe complication seen in patients with APL treated with all-trans retinoic acid (ATRA) and/or arsenic trioxide (ATO). The presenting symptoms of APL DS are diverse, and rare symptoms are easy to be misdiagnosed. Therefore, it is very crucial to identify DS from uncommon signs to avoid delay in treatment.Case Presentation: Here, we report a patient of APL who developed severe abdominal pain during ATRA and ATO therapy, with increasing leukocyte count. Organic diseases were firstly excluded, and empiric treatment for DS was adopted. The abdominal pain was gradually relieved and the patient eventually achieved complete remission.Conclusion: This case history suggests that APL DS may manifest as severe abdominal pain, and the early identification of DS and immediate treatment could improve the prognosis of patients.Keywords: acute promyelocytic leukemia, all-trans-retinoic acid, arsenic trioxide, differentiation syndrome, abdominal pain, case report

Background: Accumulation of evidence suggests that the gut microbiome, its specific metabolites, and differentially expressed proteins (DEPs) are related to non‐small cell lung cancer (NSCLC) pathogenesis. We now report the influences of the gut microbiota, metabolites, and DEPs on the mediation of NSCLC's chronic inflammation and immune dysregulation. Methods: We conducted 16S ribosomal RNA sequencing for the gut microbiome in healthy volunteers and NSCLC patients. Liquid chromatography–mass spectrometry (LC–MS) analysis was employed to explore differences between metabolites and DEPs in serum samples. Additionally, LC–MS‐based metabolomic analysis was conducted in 40 NSCLC tissues and 40 adjacent tissues. The omics data were separately analysed and integrated by using Spearman's correlation coefficient. Then, faecal microbiota transplantation (FMT) assay was used to assess the effects of the gut microbiome and specific metabolites in mice. Results: Faecal microbiome analysis revealed gut microflora dysbiosis in NSCLC patients with Prevotella, Gemmiger, and Roseburia significantly upregulated at the genus level. Then, we identified that nervonic acid/all‐trans‐retinoic acid level was negatively related to Prevotella. Additionally, a total of core 8 DEPs were selected in the proteome analysis, which mainly participated in the production of IL‐8 and NF‐κB pathways. CRP, LBP, and CD14 were identified as potential biomarkers for NSCLC. Transplantation of faecal microbiota from patients with NSCLC or Prevotella copri‐colonized recipient in mice resulted in inflammation and immune dysregulation. In turn, nervonic acid/all‐trans‐retinoic acid treatment improved the phenotype of C57BL/6 mice bearing P. copri‐treated Lewis lung cancer (LLC). Conclusions: Overall, these results pointed out that P. copri‐nervonic acid/all‐trans‐retinoic acid axis may contribute to the pathogenesis of NSCLC. [ABSTRACT FROM AUTHOR]

The title compound, C33H50N2O2, is a side product in the reaction of all-trans-retinoic acid (atRA) with N-hydroxysuccinimide, in the presence of the coupling agent N,N′-dicyclohexylcarbodiimide, which produces the 'active' ester succinimidyl all-trans-retinoate as the product. It crystallizes in the orthorhombic Pbca space group. The compound was characterized by 1H-NMR, 13C-NMR, ESI–MS and IR spectroscopy and its structure was determined by single-crystal X-ray diffraction. For example in the 13C-NMR spectrum, diagnostic peaks are those of the two amide carbonyl C atoms at δ 169.5 and 154.2 ppm, the ten olefinic C atoms of the unsaturated chain of atRA moiety at δ 149.0, 139.3, 137.7, 137.3, 134.9, 130.2, 130.0, 129.4, 128.5 and 121.5 ppm and the two methine C atoms of the N,N′-dicyclohexylurea moiety at δ 57.9 and 49.5 ppm. Detailed analysis of its molecular and supramolecular structure showed that close-packing principles (elongated shape/large hydrophobic region of the molecule) together with chemical factors (N–H⋯O and C–H⋯O intermolecular interactions) direct the 3D self-assembly process in the crystalline state. Hirshfeld surface analysis was employed, a powerful approach to quickly and easily gain insight into molecular environments in the crystalline state. The synthesis and X-ray structure of 1-((2E, 4E, 6E, 8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-1-enyl)nona-2,4,6,8-tetraenoyl)-1,3-dicyclohexylurea, a side product in the synthesis of succinimidyl all-trans-retinoate, is reported; Hirshfeld surface analysis was employed to identify intermolecular interactions. [ABSTRACT FROM AUTHOR]

All-trans-retinoic acid (ATRA) has transformed the treatment of acute promyelocytic leukemia. Most of the adverse effects associated with this drug are minor barring differentiation syndromes. Genital ulcers feature among the underreported adverse effects of ATRA which needs to be kept in mind to avoid life-threatening complications. We describe two cases who developed genital ulcers while treated with ATRA. [ABSTRACT FROM AUTHOR]

AIM: To explore the apoptosis of ARPE-19 cells after the treatment with different doses of all-trans-retinoic acid (ATRA). METHODS: ARPE-19 cells were used in the in-vitro experiment. Flow cytometry assay was employed to evaluate the level of reactive oxygen species (ROS) and apoptosis. The effects of ATRA (concentrations from 2.5 to 20 μmol/L) on the expression of endoplasmic reticulum stress (ERS) markers in vitro were evaluated by Western blot and real-time quantitative polymerase chain reaction (qRT-PCR) assays. The contribution of ROS and ERS-induced apoptosis in vitro was determined by using N-acetyl-L-cysteine (NAC) and Salubrinal, an antagonist of NAC and ERS, respectively. RESULTS: Flow cytometry showed that ATRA significantly increased ARPE-19 cell apoptosis and ROS levels in each group (F=86.39, P

All-trans retinoic acid (RA) is an effective anti-aging chemical substance widely used in skin-care products. RA compromises epidermal differentiation and induces keratinocyte proliferation, causing hyaluronic acid production through mechanisms that are not completely understood. Klotho protein causes the differentiation of human epidermal keratinocytes. Klotho gene expression is mediated by epidermal growth factor (EGF), which inhibits cell apoptosis in aging-related diseases. The klotho gene causes human aging syndrome, including short lifespan, skin atrophy, and osteoporosis. We investigated the relationship between RA and klotho in epidermal keratinocytes for the first time. In human epidermal keratinocytes, RA induced klotho gene expression. Treatment with both RA and recombinant klotho induced hyaluronic acid production in human epidermal keratinocytes. However, in klotho small interfering RNA (siRNA)-transfected keratinocytes, RA produced less hyaluronic acid than in the control group, indicating that RA may partially regulate hyaluronic acid production through a klotho-dependent pathway. Knockdown of klotho gene expression inactivated the EGFR-extracellular signal-regulated kinase (ERK) signaling pathway, which is involved in hyaluronic acid production. We concluded that the effect of RA on hyaluronic acid production is partly regulated through the klotho-mediated EGFR signaling pathway in human epidermal keratinocytes. [ABSTRACT FROM AUTHOR]

Vitamin A, acting through its metabolite, all-trans-retinoic acid, is a potent transcriptional regulator affecting expression levels of hundreds of genes through retinoic acid response elements present within these genes. However, the literature is replete with claims that consider vitamin A to be an antioxidant vitamin, like vitamins C and E. This apparent contradiction in the understanding of how vitamin A acts mechanistically within the body is a major focus of this review. Vitamin E, which is generally understood to act as a lipophilic antioxidant protecting polyunsaturated fatty acids present in membranes, is often proposed to be a transcriptional regulator. The evaluation of this claim is another focus of the review. We conclude that vitamin A is an indirect antioxidant, whose indirect function is to transcriptionally regulate a number of genes involved in mediating the body's canonical antioxidant responses. Vitamin E, in addition to being a direct antioxidant, prevents the increase of peroxidized lipids that alter both metabolic pathways and gene expression profiles within tissues and cells. However, there is little compelling evidence that vitamin E has a direct transcriptional mechanism like that of vitamin A. Thus, we propose that the term antioxidant not be applied to vitamin A, and we discourage the use of the term transcriptional mediator when discussing vitamin E. [ABSTRACT FROM AUTHOR]

Abstract Introduction EVI1 (MECOM)-positive acute myeloid leukemia (AML) cells have shown in vitro sensitivity to all-trans-retinoic acid (ATRA) by inducing differentiation, cell death, and decreased leukemic engraftment. Methods In this pilot study, we investigated the response to ATRA in 13 high-risk AML patients with overexpression of EVI1. Results Seven of the 13 patients (53.8%) achieved complete remission (CR), and response can be combined with a decreased of the leukemia stem cell pool. Conclusion These primary results tend to confirm in vitro results and suggest that addition of ATRA might be of benefit in the treatment of patients with EVI1-positive AML.

Background: Lichen planus is an inflammatory disease that affects the skin, the oral mucosa, or both.  Generalized cutaneous lichen planus may pose a therapeutic challenge for clinicians if the condition persists or flares after topical or systemic corticosteroid therapy.Purpose: Acitretin, a systemic retinoid, can be considered a potential second-line treatment for patients with generalized cutaneous lichen planus.  Herein, we describe a postmenopausal woman with generalized cutaneous lichen planus who was successfully treated with acitretin.Methods: A 58-year-old woman presented with generalized cutaneous lichen planus involving her upper and lower extremities as well as her lower back.  After failing corticosteroid therapy, she was started on acitretin 20 mg/day, which was later increased to 30 mg/day.  To review the literature on the use of acitretin in cutaneous lichen planus, we used the PubMed search engine and searched for the terms “acitretin” and “cutaneous lichen planus.”Results: Our patient had complete resolution of pruritus within one week of initiating acitretin 20 mg/day.  After an increase in dose to 30 mg/day, the cutaneous lesions completely resolved over a 3-month period.  There was no recurrence of disease as acitretin was tapered and discontinued.Conclusion: Generalized cutaneous lichen planus may pose a therapeutic challenge for the symptomatic relief of skin lesions.  Topical and systemic corticosteroids are first-line treatments.  In patients who fail corticosteroids, relapse after corticosteroid therapy, or have contraindications to corticosteroids, acitretin may be considered a potential second-line therapy.

We previously demonstrated that IL4, IL13, CLCA1, and CCL26 mRNA were significantly upregulated in the lungs of pigs given a low dose of all trans-retinoic acid (ATRA) and infected with Ascaris suum. We also demonstrated that in vitro ATRA induced a state of partial alternative activation in porcine macrophages (Mφs) and amplified certain aspects of M2a activation induced by IL-4. Given these results, we tested the effect of ATRA on IL-4 responses in two porcine intestinal epithelial cell lines, IPEC1 and IPEC-J2 and observed that ATRA increased mRNA for the IL-4 receptor alpha chain. ATRA also increased IL-4 induced phosphorylation of signal transducer and activator of transcription 6 (STAT6) and mRNA expression of the chloride channel, calcium activated, family member 1 (CLCA1), important for mucus formation, and chemokine (C-C motif) ligand 26 (CCL26), a potent eosinophil chemoattractant. We extended these findings to human Mφ THP-1 cells and showed that ATRA synergistically increased IL-4–induced CCL2, CCL13, and CCL26 mRNA and protein levels. Transglutaminase 2 mRNA, protein, and enzyme activity were synergistically induced in THP-1 cells pretreated with ATRA and then treated with IL-4, thus, ATRA increased signaling in response to IL-4 in porcine epithelial cells and porcine and human Mφs. Given the prevalence of allergic and parasitic diseases worldwide and the close similarities in the porcine and human immune responses, these findings have important implications for the nutritional regulation of allergic inflammation at mucosal surfaces.

Abstract Background Cancer stem cells (CSCs) are highly proliferative and tumorigenic, which contributes to chemotherapy resistance and tumor occurrence. CSCs specific therapy may achieve excellent therapeutic effects, especially to the drug-resistant tumors. Results In this study, we developed a kind of targeting nanoparticle system based on cationic albumin functionalized with hyaluronic acid (HA) to target the CD44 overexpressed CSCs. All-trans-retinoic acid (ATRA) was encapsulated in the nanoparticles with ultrahigh encapsulation efficiency (EE%) of 93% and loading content of 8.37%. TEM analysis showed the nanoparticles were spherical, uniform-sized and surrounded by a coating layer consists of HA. Four weeks of continuously measurements of size, PDI and EE% revealed the high stability of nanoparticles. Thanks to HA conjugation on the surface, the resultant nanoparticles (HA-eNPs) demonstrated high affinity and specific binding to CD44-enriched B16F10 cells. In vivo imaging revealed that HA-eNPs can targeted accumulate in tumor-bearing lung of mouse. The cytotoxicity tests illustrated that ATRA-laden HA-eNPs possessed better killing ability to B16F10 cells than free drug or normal nanoparticles in the same dose, indicating its good targeting property. Moreover, HA-eNPs/ATRA treatment decreased side population of B16F10 cells significantly in vitro. Finally, tumor growth was significantly inhibited by HA-eNPs/ATRA in lung metastasis tumor mice. Conclusions These results demonstrate that the HA functionalized albumin nanoparticles is an efficient system for targeted delivery of antitumor drugs to eliminate the CSCs.

B-cell acute lymphoblastic leukemia (B-ALL) is a diverse group of malignant blood disorders both with regard to the biological properties of the tumor and to therapeutic approaches. Immunophenotyping, molecular genetic techniques, whole-genome sequencing characterize B-ALL as a very diverse group for sensitivity to chemotherapy and prognosis. We present three clinical cases of patients with B-ALL and expected good response to standard therapy, in whom standard protocol treatment failured: refractoriness, persistence of minimal residual disease (MRD), and progression (MRD increase). The remission in these patients was achieved after chemotherapy change to immunological targeted therapy. Nowadays a unified therapeutic approach to all primary patients of the B-ALL is considered generally outdated. Great efforts are carrying out to develop molecular genetic classifications. The molecular dissection of subtypes of B-ALL goes on, and new protocols for selective treatment with targeting are clearly outlined for each subtype of B-ALL.

Summary: Severe acquired aplastic anaemia (AA) is a serious disease characterised by autoreactive T cells attacking haematopoietic stem cells, leading to marrow hypoplasia and pancytopenia. Immunosuppressive therapy combined with antithymocyte globulin and ciclosporin can rescue most patients with AA. However, the relapse after ciclosporin withdrawal and the severe side effects of long‐term ciclosporin administration remain unresolved. As such, new strategies should be developed to supplement current therapeutics and treat AA. In this study, the possibility of all‐trans‐retinoic acid (ATRA) as an alternative AA treatment was tested by using an immune‐mediated mouse model of AA. Results revealed that ATRA inhibited T‐cell proliferation, activation and effector function. It also restrained the Fas/Fasl pathway, shifted Th1 towards Th2 cell development, rebalanced T‐cell subsets at a relatively high level and corrected the Th1/Th2 ratio by targeting NFAT1 signalling. In addition, ATRA inhibited Th17 cell differentiation and promoted regulatory T‐cell development. Therefore, ATRA was an effective agent to improve AA treatment outcomes. [ABSTRACT FROM AUTHOR]

Introduction: Acute promyelocytic leukemia is an oncologic emergency. The limited cases reported in the literature have led to poor understanding of the safety of management of acute promyelocytic leukemia during pregnancy. Case report: Herein is an acute promyelocytic leukemia case of a 22-year-old young pregnant woman who had various social problems. The patient was diagnosed with acute promyelocytic leukemia in her the second trimester of her first pregnancy. Management and outcome: She was treated with all-trans-retinoic acid with idarubicin and successfully delivered a healthy baby. She completed induction with idarubicin but defaulted her all-trans-retinoic acid, 6-mercaptopurine and methotrexate maintenance. She relapsed after one year and was salvaged with all-trans-retinoic acid high dose cytarabine and arsenic trioxide. She went into remission and had autologous stem cells collected and was planned for an autologous stem cell transplant but she defaulted. She relapsed when she was pregnant with her second baby during her third trimester (29+weeks) 10 months later. Salvage chemotherapy with arsenic trioxide, all-trans-retinoic acid and idarubicin was given. Patient underwent an emergency lower segment caesarian section at 31 weeks of pregnancy due to abnormal fetal cardiotocography. A healthy baby was delivered. Discussion: This drug regimen is controversial during pregnancy owing to the teratogenic effects and fatal retinoic acid syndrome especially in early gestation. In this case, patient was started the induction therapy of all-trans-retinoic acid treatment at her second trimester during her first pregnancy. Conclusion: Our lady demonstrated the possibility of using all-trans-retinoic acid and arsenic trioxide and chemotherapy during second and third trimester with successful pregnancy outcomes. [ABSTRACT FROM AUTHOR]

The prognosis of patients with acute myeloid leukemia (AML) caused by the FLT3-ITD mutation is poor. Arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) can down-regulate FLT3-ITD level and selectively kill leukemia cells carrying the FLT3-ITD mutation. However, the mechanisms of action of these two compounds are unknown. Here, we found that ATO could bind FLT3-ITD at Lys91 and Asp225, whereas ATRA could bind FLT3-ITD at Lys5 and Gln6. Both compounds could not bind wild-type FLT3. Further studies revealed that ATO/ATRA may suppress the Expression of FLT3-ITD by promoting the UBE2L6-mediated ubiquitination pathway and decreasing the expression of C-MYC. However, further studies are needed to define the mechanisms of these compounds on AML. Our research provides an experimental basis for the use of ATO/ATRA in FLT3-ITD AML in clinical practice. [ABSTRACT FROM AUTHOR]

Aims: Failure of neural tube closure resulting from excessive apoptosis leads to neural tube defects (NTDs). NADPH oxidase 4 (NOX4) is a critical mediator of cell growth and death, yet its role in NTDs has never been characterized. NOX4 is a potential target of miR‐322, and we have previously demonstrated that miR‐322 was involved in high glucose‐induced NTDs. In this study, we investigated the effect of NOX4 on the embryonic neuroepithelium in NTDs and reveal a new regulatory mechanism for miR‐322 that disrupts neurulation by ameliorating cell apoptosis. Methods: All‐trans‐retinoic acid (ATRA)‐induced mouse model was utilized to study NTDs. RNA pull‐down and dual‐luciferase reporter assays were used to confirm the interaction between NOX4 and miR‐322. In mouse neural stem cells and whole‐embryo culture, Western blot and TUNEL were carried out to investigate the effects of miR‐322 and NOX4 on neuroepithelium apoptosis in NTD formation. Results: NOX4, as a novel target of miR‐322, was upregulated in ATRA‐induced mouse model of NTDs. In mouse neural stem cells, the expression of NOX4 was inhibited by miR‐322; still further, NOX4‐triggered apoptosis was also suppressed by miR‐322. Moreover, in whole‐embryo culture, injection of the miR‐322 mimic into the amniotic cavity attenuated cell apoptosis in NTD formation by silencing NOX4. Conclusion: miR‐322/NOX4 plays a crucial role in apoptosis‐induced NTD formation, which may provide a new understanding of the mechanism of embryonic NTDs and a basis for potential therapeutic target against NTDs. [ABSTRACT FROM AUTHOR]

In recent years, microfluidic devices present unique advantages for the development of a new generation of nanoparticle synthesis method compared to bulk methods. In this study, we report a microfluidic flow-focusing method for the production of all trans retinoic acid (ATRA)-loaded methoxy poly(ethylene glycol)-poly(lactide-coglycolide) (mPEG-PLGA) nanoparticles (NPs). Box–Behnken experimental design (BBD) was applied to optimize of formulation ingredients and process conditions with minimum particle size, maximum drug loading% (DL%) and encapsulation efficiency% (EE%). Polymer concentration, drug concentration and flow rates of solvent (S) and antisolvent (AS) were selected as independent variables. Based on optimization strategy, minimum particle size achieved shows average (SD) particle size of 1 5 9 ± 8 nm with DL of 7. 1 ± 0. 0 4 wt.% and EE of 9 8. 7 1 ± 0. 5 8 wt.%, respectively. While maximum DL has been reported to be 1 6. 5 1 ± 0. 0 3 wt.% with particle size of 2 0 5 ± 5. 2 9 nm and EE of 9 9. 4 2 ± 0. 4 5 wt.%, respectively. Moreover, the results have shown that the AS/S ratio represents the most significant effect on particle size. Indeed, increasing the AS flow rate directly results in generating smaller particles. The AS/S ratio represents the least significant effect on DL%, such that, at fixed flow rates, higher DL was observed at high concentration of drug and lower concentration of polymer. In conclusion, optimization of the ATRA-loaded mPEG-PLGA NPs by BBD yielded in a favorable drug carrier for ATRA that could provide a new treatment modality for different malignancies. A transparent t-shaped microfluidic device consists of three inlets and one main mixing outlet channel was designed and constructed using glass wafer in order to synthesize ATRA loaded mPEG-PLGA nanoparticles. The influence of flow rate ratio, polymer concentration, and drug concentration on the nanoparticles' size has been investigated. An optimized ATRA loaded mPEG-PLGA NPs could provide a new treatment modality for different malignancies. [ABSTRACT FROM AUTHOR]

We previously demonstrated that IL4, IL13, CLCA1, and CCL26 mRNA were significantly upregulated in the lungs of pigs given a low dose of all trans-retinoic acid (ATRA) and infected with Ascaris suum. We also demonstrated that in vitro ATRA induced a state of partial alternative activation in porcine macrophages (Mφs) and amplified certain aspects of M2a activation induced by IL-4. Given these results, we tested the effect of ATRA on IL-4 responses in two porcine intestinal epithelial cell lines, IPEC1 and IPEC-J2 and observed that ATRA increased mRNA for the IL-4 receptor alpha chain. ATRA also increased IL-4 induced phosphorylation of signal transducer and activator of transcription 6 (STAT6) and mRNA expression of the chloride channel, calcium activated, family member 1 (CLCA1), important for mucus formation, and chemokine (C-C motif) ligand 26 (CCL26), a potent eosinophil chemoattractant. We extended these findings to human Mφ THP-1 cells and showed that ATRA synergistically increased IL-4–induced CCL2, CCL13, and CCL26 mRNA and protein levels. Transglutaminase 2 mRNA, protein, and enzyme activity were synergistically induced in THP-1 cells pretreated with ATRA and then treated with IL-4, thus, ATRA increased signaling in response to IL-4 in porcine epithelial cells and porcine and human Mφs. Given the prevalence of allergic and parasitic diseases worldwide and the close similarities in the porcine and human immune responses, these findings have important implications for the nutritional regulation of allergic inflammation at mucosal surfaces. [ABSTRACT FROM AUTHOR]

All-trans-retinoic acid (ATRA), the active metabolite of vitamin A, plays a pivotal role in cell differentiation, proliferation and embryonic development. It is an effective therapy for dermatological disorders and malignancies. ATRA is prone to isomerization and oxidation, which can affect its activity and selectivity. Novel diphenylacetylene-based ATRA analogues with increased stability can help to overcome these problems and may offer significant potential as therapeutics for a variety of cancers and neurodegenerative diseases, including amyotrophic lateral sclerosis. Here, we investigated the effects of these retinoids on cell viability and genotoxicity in the widely used model system of the rapidly proliferating Chinese hamster ovary cell line. DC360 is a fluorescent ATRA analogue and DC324 is a non-active derivative of DC360. EC23, DC525, DC540, DC645, and DC712 are promising analogues with increased bioactivity. The cytotoxic activity of the compounds was evaluated by ATP assay and DNA damage was tested by comet assay. No cytotoxicity was observed in the 10−6–10−5 M concentration range. All compounds induced DNA migration similar to ATRA, but DC324, DC360 and EC23 did so to a greater extent, particularly at higher concentrations. We believe that retinoid receptor-independent genotoxicity is a general characteristic of these compounds; however, further studies are needed to identify the molecular mechanisms and understand their complex biological functions.

The proliferation and migration of vascular smooth muscle cells (VSMC) is extensively involved in pathogenesis of neointimal hyperplasia. All-trans-retinoic acid (ATRA) is a natural metabolite of vitamin A. Here, we investigated the involvement of AMP-activated protein kinase (AMPK) in the anti-neointimal hyperplasia effects of ATRA. We found that treatment with ATRA significantly reduced neointimal hyperplasia in the left common carotid artery ligation mouse model. ATRA reduced the proliferation and migration of VSMC, A7r5 and HASMC cell lines. Our results also demonstrated that ATRA altered the expression of proliferation-related proteins, including CyclinD1, CyclinD3, CyclinA2, CDK2, CDK4, and CDK6 in VSMC. ATRA dose-dependently enhanced the phosphorylation level of AMPKα (Thr172) in the left common carotid artery of experimental mice. Also, the phosphorylation level of AMPKα in A7r5 and HASMC was significantly increased. In addition, ATRA dose-dependently reduced the phosphorylation levels of mTOR and mTOR target proteins p70 S6 kinase (p70S6K) and 4E-binding protein 1 (4EBP1) in A7r5 and HASMC. Notably, the inhibition of AMPKα by AMPK inhibitor (compound C) negated the protective effect of ATRA on VSMC proliferation in A7r5. Also, knockdown of AMPKα by siRNA partly abolished the anti-proliferative and anti-migratory effects of ATRA in HASMC. Molecular docking analysis showed that ATRA could dock to the agonist binding site of AMPK, and the binding energy between AMPK and ATRA was -7.91 kcal/mol. Molecular dynamics simulations showed that the binding of AMPK-ATRA was stable. These data demonstrated that ATRA might inhibit neointimal hyperplasia and suppress VSMC proliferation and migration by direct activation of AMPK and inhibition of mTOR signaling.

All-trans retinoic acid (ATRA) has been studied for the treatment of cancer, including leukemia and breast cancer. This work aims to develop nanoemulsions (NE) loaded with a hydrophobic ion pair (HIP) of all-trans retinoic acid (ATRA) and a lipophilic amine, stearylamine (SA), and coated with hyaluronic acid (HA) to enhance anticancer activity and reducing toxicity. Blank NE was prepared by spontaneous emulsification and optimized prior to HIP incorporation. NE-ATRA was electrostatically coated with different concentrations of HA. Incorporation of ATRA-SA led to monodisperse NE with small size (129 ± 2 nm; IP 0.18 ± 0.005) and positive zeta potential (35.7 ± 1.0 mV). After coating with 0.5 mg/mL HA solution, the mean diameter slightly increased to 158 ± 5 nm and zeta potential became negative (-19.7 ± 1.2 mV). As expected, high encapsulation efficiency (near 100%) was obtained, confirmed by polarized light microscopy and infrared analysis. Formulations remained stable over 60 days and release of ATRA from NE was delayed after the hydrophilic HA-coating. HA-coated NE-ATRA was more cytotoxic than free ATRA for MDA-MB-231 and MCF-7 breast cancer cell lines, especially in the CD44 overexpressing cells. Blank coated formulations showed no cytotoxicity. These findings suggest that this easily-made HA-coated NE-ATRA formulation is a promising alternative for parenteral administration, thus improving the breast cancer therapy with this drug.

A 68-year-old male was diagnosed with acute promyelocytic leukemia (APL). A G-banding chromosomal analysis revealed the co-existence of two clones: one with del(20q) and t(15;17)(q22;q12) and another with del(20q) alone. During the remission of APL following treatment with all-trans-retinoic acid, del(20q) was persistently identified, indicating a diagnosis of cytogenetic abnormalities of undetermined significance (CCAUS) with isolated del(20q). Bicytopenia developed 48 months after the remission of APL. The presence of isolated del(20q) was detected in the G-banding analysis, whereas morphological dysplasia of hematopoietic cells was not confirmed. This case showed indolent progression from CCAUS after the remission of APL to clonal cytopenia of undetermined significance (CCUS). CCUS with isolated del(20q) persisted for 24 months without any finding of hematological malignancies. At the most recent follow-up, targeted capture sequencing showed the U2AF1 S34F mutation. Considerable attention needs to be paid in follow-ups for CCAUS with del(20q) after the treatment of leukemia. [ABSTRACT FROM AUTHOR]

Background: Despite advances in the treatment of acute promyelocytic leukemia (APL) with all‐trans‐retinoic acid (ATRA), its underlying mechanism has not been fully elucidated. The oncogenic microRNA cluster miR‐17‐92 modulates multiple cellular processes, including survival, proliferation, and apoptosis. However, the role of miR‐17‐92 and its regulation has not yet been documented for APL. Methods: We analyzed miR‐17‐92 expression in APL samples and cell lines by qRT‐PCR. The expression of c‐Myc was measured by western blot. Cell differentiation was assessed by measuring the surface CD11b antigen expression by flow cytometry analysis. Results: We observed that miR‐17‐92 was upregulated in APL compared with healthy donors. Furthermore, we demonstrated that expressions of c‐Myc and miR‐17‐92 are markedly suppressed during ATRA‐induced NB4 cell differentiation. Importantly, we also demonstrated that miR‐17‐92 is directly regulated by c‐Myc during the granulocytic differentiation of APL cells. Finally, the overexpression of miR‐17‐5p blocks ATRA‐induced differentiation. Conclusions: We report abnormal expression of the miR‐17‐92 cluster in APL cells, which is responsible for the differentiation block in blast cells in APL. In addition, we identified miR‐17‐92 as a target gene of c‐Myc during ATRA‐induced granulocytic differentiation. [ABSTRACT FROM AUTHOR]

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Introduction: EVI1 (MECOM)-positive acute myeloid leukemia (AML) cells have shown in vitro sensitivity to all-trans-retinoic acid (ATRA) by inducing differentiation, cell death, and decreased leukemic engraftment. Methods: In this pilot study, we investigated the response to ATRA in 13 high-risk AML patients with overexpression of EVI1. Results: Seven of the 13 patients (53.8%) achieved complete remission (CR), and response can be combined with a decreased of the leukemia stem cell pool. Conclusion: These primary results tend to confirm in vitro results and suggest that addition of ATRA might be of benefit in the treatment of patients with EVI1-positive AML. [ABSTRACT FROM AUTHOR]

Conjunctival fiber generation is implicated in a wide spectrum of ocular diseases. Conjunctival wound healing is characterized by inflammation followed by re-epithelialization, synthesis of new extracellular matrix (ECM), wound contraction and subconjunctival scar formation. The primary cause for the failure of glaucoma filtration surgery results from the excessive scarring of the filtering bleb. All-trans-retinoic acid (ATRA), a derivative of vitamin A, is a potent regulator of ECM synthesis, growth and differentiation. Following a previous study, which revealed that ATRA could inhibit transforming growth factor-β-induced human conjunctival fibroblast (HConF)-mediated collagen gel contraction, the present study aimed to investigate the effects of ATRA on HConF migration, apoptosis, proliferation and ECM synthesis. To achieve this, the present study used Transwell migration, wound healing and Cell Counting Kit-8 assays, flow cytometry and western blot analysis. In addition, the present study aimed to elucidate the mechanism of ATRA in mediating resistance to conjunctival scar formation. ATRA treatment resulted in an increased level of HConF apoptosis, reduced proliferation and migration, decreased collagen I and fibronectin expression, and decreased phosphorylation of PI3K and AKT. Thus, the present study showed a role for ATRA in inhibiting HConF migration, proliferation and ECM synthesis, and in promoting HConF apoptosis through the inhibition of the PI3K/AKT signaling pathway. [ABSTRACT FROM AUTHOR]

Arsenic has been known for centuries for its double-edged potential: a poison and at the same time a therapeutic agent. The name "arsenikon," meaning "potent," speaks itself for the pharmaceutical properties of this compound, questioned and analyzed for at least 2000 years. In the last decades, acute promyelocytic leukemia (APL) has evolved from a highly fatal to a curable disease, due to the use of all-trans-retinoic acid and, more recently, arsenic trioxide combinations. The success of these entirely chemo-free regimens increased the awareness of APL and reduced the prevalence of early deaths, which was an impending issue in this disease. Further improvements are expected with the next use of oral arsenic formulations, which will allow a complete outpatient approach, at least in the post-induction settings, further improving patients' quality of life. The wide use of standardized approaches in APL will also help unravel long-standing open questions, including the pathogenesis, prevention, and treatment of the differentiation syndrome and of short-term organ toxicities. In the long term, the study of survivorship issues, such as fertility and organ-related and psychological damages, in the increasing number of survivors will help further improve their life after APL. [ABSTRACT FROM AUTHOR]

We previously demonstrated that the most bioactive vitamin A metabolite, all-trans retinoic acid (ATRA), increased T helper 2-associated responses induced in pigs by infection with the parasitic nematode Ascaris suum We also showed that ATRA potentiated the mRNA expression of several IL-4 induced chemokines (chemokine (C C motif) ligand 11 [(CCL11), CCL17, CCL22 and CCL26] associated with alternative activation (M2a) in porcine macrophages in vitro. Herein, several mechanisms whereby ATRA affects IL-4 signaling are profiled using large-scale real time PCR and RNA-Seq analysis. Twenty-three genes associated with M2a markers in other species were independently upregulated by both IL-4 and ATRA, including the adenosine receptor A2B (ADORA2B), cysteinyl leukotriene receptor 2 (CYSLTR2) and the vitamin D receptor (VDR). ATRA synergistically enhanced IL-4 up-regulation of Hepatitis A virus cellular receptor 2 (HAVCR2) and transglutaminase 2 (TGM2) and further repressed IL-4 down-regulated CD163 and Cytochrome b-245, beta polypeptide (CYBB) mRNA. Macrophages treated with ATRA exhibited a dose-dependent reduction in phagocytosis of opsonized Staphylococcus aureus. In addition, the combination of IL-4 and ATRA up-regulated the anti-inflammatory protein, IL-1R antagonist (IL1RN) and TGM2. These data indicate that ATRA induces a state of partial alternative activation in porcine macrophages, and amplifies certain aspects of M2a activation induced by IL-4. Given the prevalence of allergic and parasitic diseases worldwide and the close similarities in the porcine and human immune responses, these findings have important implications for the nutritional regulation of allergic inflammation at mucosal surfaces. • We identified 23 mRNA that are independently induced by both RA and IL-4 associated with the M2 activation state. • We also identified 18 additional mRNA that increase or decrease synergistically, when macrophages are exposed to IL-4 and RA. • We observed a reduction in phagocytosis of Staphylococcus aureus, in cells treated with either IL-4 or RA. • We observed that combination of RA and IL-4 induced the interleukin 1 receptor antagonist and the M2a marker, TGM2, proteins. [ABSTRACT FROM AUTHOR]

Abstract FoxP3 is a transcription factor essential for differentiation and function of T regulatory cells (Tregs). There are two major subsets of Tregs: natural Tregs (nTregs) generated in thymus and inducible Tregs (iTregs) produced in peripheral immune system. It has been documented that iTreg development is dependent on soluble mediators including interleukin 2 (IL2), transforming growth factor β (TGFβ) and all- trans -retinoic acid (ATRA). In our experiments we performed a gene expression array, followed by Real-time PCR experiments to study expression of genes regulated by ATRA in cells of myeloid origin. Our experiments revealed that ATRA alone, but also a cocktail of mediators consisting of IL2, TGFβ and ATRA, upregulate expression of FOXP3 gene in normal and leukemic myeloid cells. Our results indicate that signaling pathways which are used at the late steps of T cell differentiation, are also active in the cells of myeloid lineage. Highlights • We discover that FOXP3 expression is upregulated by ATRA in HL60 cells. • FOXP3 encodes a master regulator of regulatory T cells, while HL60 cells belong to myeloid lineage of blood differentiation. • Combination of ATRA, IL2 and TGFβ upregulates FOXP3 in Jurkat which belong to lymphoid lineage. • ATRA and IL2 and TGFβ upregulate FOXP3 in HL60 cells stronger than in Jurkat cells. • ATRA and IL2 and TGFβ upregulate FOXP3 in normal human myeloid cells. [ABSTRACT FROM AUTHOR]

Anti‐epidermal growth factor receptor (EGFR) drugs including erlotinib cause a side effect of hypomagnesemia. In lung adenocarcinoma A549 cells, anticancer agents such as cisplatin and doxorubicin dose‐dependently increased toxicity, but the effects were significantly suppressed by culturing the cells in low Mg2+‐containing media. To obtain the maximum effect in cancer chemotherapy, it should be necessary to prevent the reduction of body Mg 2+ content. Anti‐EGFR drugs inhibit EGF‐induced elevation of transient receptor potential melastatin 6 (TRPM6) Mg 2+ channel in renal tubular epithelial NRK‐52E cells. Here, we found that rosiglitazone, an antidiabetic drug, and all‐ trans‐retinoic acid (ATRA), a vitamin A derivative, increase the messenger RNA (mRNA) level of TRPM6 in the presence of erlotinib. The rosiglitazone‐ and ATRA‐induced elevation of mRNA level, Mg 2+ influx, and promoter activity of TRPM6 were inhibited by GW‐9662, a potent antagonist of peroxisome proliferator‐activated receptor (PPAR)γ, and LE135, a retinoic acid receptor (RAR) antagonist, respectively. Rosiglitazone increased the phosphorylation and nuclear localization levels of PPARγ, which were inhibited by GW‐9662. In contrast, RAR was mainly distributed in the nuclei under control conditions, which was unchanged by ATRA and LE135. The promoter activity of TRPM6 was inhibited by a mutation in the peroxisome proliferator hormone response element (PPRE). A chromatin immunoprecipitation assay revealed that PPARγ and RAR bind to the PPRE, which was blocked by GW‐9662 and LE135, respectively. These results suggest that rosiglitazone and ATRA reverse the reduction in Mg 2+ reabsorption caused by anti‐EGFR drugs. Rosiglitazone and all‐trans‐retinoic acid (ATRA) increased transient receptor potential melastatin 6 (TRPM6) expression in renal tubular epithelial cells. Rosiglitazone and ATRA increased Mg 2+ influx. Rosiglitazone and ATRA may reverse the reduction in Mg 2+ reabsorption caused by antiepidermal growth factor receptor (anti‐EGFR) drugs. [ABSTRACT FROM AUTHOR]

Abstract The retinoid system controls essential cellular processes including mitosis, differentiation and metabolism among others. Although the retinoid-signalling pathway is a potential target for the action of several endocrine disrupting chemicals (EDCs), the information about the developmental effects of bisphenol-A (BPA) on the hepatic retinoid system is scarce. Herein, male mice were in utero exposed to BPA following maternal subcutaneous doses of 0, 10 and 100 μg/kg bw/day from gestational day 9–16 and they were sacrificed at post-natal day 30. Retinoid concentrations and gene expression of key elements involved in the retinoid system were determined in liver. BPA increased all- trans -retinoic acid concentration and expression of Adh1 , Aox1 and Cyp1a2 (biosynthesis of retinoic acid), while reduced Mrp3 (efflux from hepatocyte to blood), increased Bcrp expression (biliary excretion) and changed the retinoid-dependent signalling system after reducing expression of Rxrβ and increasing that of Fgf21. Furthermore, we found bivariate associations of Rarγ and Rxrγ expressions with all- trans -retinoic acid concentrations and of Fgf21 expression with that of Rarγ. Those findings occurred in animals which showed altered pancreatic function and impaired glucose metabolism during adulthood. The present information should be useful for enhancing testing methods for the identification of EDCs. Highlights • In utero exposure to BPA induced retinoic acid biosynthesis. • BPA modulated transporter expressions towards the biliary excretion. • BPA triggered retinoid-dependent signalling. [ABSTRACT FROM AUTHOR]

Miliaria crystallina is a benign, self‐limiting disorder of the eccrine sweat glands characterized by the obstruction of the sweat ducts, which leads to secondary sweat retention into stratum corneum. We present two patients with MC during treatment with idarubicin and all‐trans‐retinoic acid (ATRA) for acute promyelocytic leukaemia (APL). Anthracyclines can be excreted through sweat and induce MC through exfoliation. The use of idarubicin in combination with ATRA would favour the process of producing a peeling effect. Reports of MC associated with idarubicin and ATRA are scarce. Recognizing this benign entity and its triggers will help to differentiate it from other skin reactions, improving the management of patients by avoiding unnecessary studies and treatments. [ABSTRACT FROM AUTHOR]