All-trans Retinoic Acid Research Articles

Recommendations for laboratory testing of UK patients with acute myeloid leukaemia.

Recommendations for laboratory testing of UK patients with acute myeloid leukaemia.

The role of BMP4 in adipose-derived stem cell differentiation: A minireview.

Bone morphogenetic protein 4 (BMP4) is a member of the transforming growth factor beta (TGF-β) superfamily of cytokines responsible for stem cells' commitment to differentiation, proliferation, and maturation. To date, various studies have utilized BMP4 as a chemical inducer for in vitro differentiation of human mesenchymal stem cells (MSCs) based on its potential. BMP4 drives in vitro differentiation of ADSC via TGF-β signaling pathway by interactions with BMP receptors leading to the activation of smad-dependent and smad-independent pathways. The BMP4 signaling pathways are regulated by intracellular and extracellular BMP4 antagonists. Extracellular BMP4 antagonist prevents interaction between BMP4 ligand to its receptors, while intracellular BMP4 antagonist shutdowns the smad-dependent pathways through multiple mechanisms. BMP4 proved as one of the popular differentiation factors to induce ADSC differentiation into cell from mesodermal origin. However, addition of all-trans retinoic acid is also needed in trans-differentiation of ADSC into ectodermal lineage cells. Suggesting that both BMP4 and RA signaling pathways may be necessary to be activated for in vitro trans-differentiation of ADSC.

Differentiation of Human Wharton Jelly Mesenchymal Stem Cells into Germ-Like Cells; emphasis on evaluation of Germ-long non-coding RNAs.

The proliferation and differentiation of stem cells into Germ-Like Cells (GLCs) is mediated by several growth factors and specific genes, of which some are related to long non-coding RNAs (lncRNAs). We have developed a modified differentiation process and identified a panel of GermlncRNAs related to GLCs. Human Wharton Jelly Mesenchymal Stem Cells were treated with 25 ng/ml Bone Morphogenetic Protein (BMP)-4 and 10- 5M all-trans retinoic acid to differentiate them into germ-like cells. To confirm the differentiation, changes in the expression of Oct-4, C-kit, Stella, and Vasa genes were assessed using quantitative Real-Time PCR (qPCR) and immunocytochemistry. QPCR was also used before and after differentiation to evaluate the changes in a lncRNA panel, using a 96-well array. Statistical analysis of the data was performed by SPSS 21. After 21 days of induction, the HWJ-MSCs derived germ-like cells were formed. Also, qPCR and immunocytochemistry showed that the pluripotent Oct4 marker was expressed in the undifferentiated HWJ-MSCs, but its expression gradually decreased in the differentiated cells. C-kit was expressed on days 7, 14, and 21 of differentiation. Both GLC markers of Stella and Vasa genes/proteins were present only in differentiated cells. Of the 44 lncRNA genes array, 36 of them showed an increase and eight genes showed a decrease. Our study showed that BMP4 and RA are effective in inducing HWJ-MSCs differentiation into GLCs. In addition, our study for the first time showed changes in the lncRNAs expression during the differentiation of HWJ-MSCs into GLCs by using BMP4 and RA.

A Multifunctional Conjugated Polymer Developed as an Efficient System for Differentiation of SH-SY5Y Tumour Cells.

Polymer-based systems have been demonstrated in novel therapeutic and diagnostic (theranostic) treatments for cancer and other diseases. Polymers provide a useful scaffold to develop multifunctional nanosystems that combine various beneficial properties such as drug delivery, bioavailability, and photosensitivity. For example, to provide passive tumour targeting of small drug molecules, polymers have been used to modify and functionalise the surface of water-insoluble drugs. This approach also allows the reduction of adverse side effects, such as retinoids. However, multifunctional polymer conjugates containing several moieties with distinct features have not been investigated in depth. This report describes the development of a one-pot approach to produce a novel multifunctional polymer conjugate. As a proof of concept, we synthesised polyvinyl alcohol (PVA) covalently conjugated with rhodamine B (a tracking agent), folic acid (a targeting agent), and all-trans retinoic acid (ATRA, a drug). The obtained polymer (PVA@RhodFR) was characterised by MALDI-TOF mass spectrometry, gel permeation chromatography, thermal analysis, dynamic light-scattering, NMR, UV-Vis, and fluorescence spectroscopy. Finally, to evaluate the efficiency of the multifunctional polymer conjugate, cellular differentiation treatments were performed on the neuroblastoma SH-SY5Y cell line. In comparison with standard ATRA-based conditions used to promote cell differentiation, the results revealed the high capability of the new PVA@RhodFR to induce neuroblastoma cells differentiation, even with a short incubation time and low ATRA concentration.

Nuclear Proteomics of Induced Leukemia Cell Differentiation.

Studies of induced granulocytic differentiation help to reveal molecular mechanisms of cell maturation. The nuclear proteome represents a rich source of regulatory molecules, including transcription factors (TFs). It is important to have an understanding of molecular perturbations at the early stages of the differentiation processes. By applying the proteomic quantitative profiling using isobaric labeling, we found that the contents of 214, 319, 376, 426, and 391 proteins were altered at 3, 6, 9, 12, and 72 h, respectively, compared to 0 h in the HL-60 cell nuclear fraction under all-trans-retinoid acid (ATRA) treatment. From 1860 identified nuclear proteins, 231 proteins were annotated as proteins with transcription factor (TF) activity. Six TFs (RREB1, SRCAP, CCDC124, TRIM24, BRD7, and BUD31) were downregulated and three TFs EWSR1, ENO1, and FUS were upregulated at early time points (3–12 h) after ATRA treatment. Bioinformatic annotation indicates involvement of the HL-60 nuclear proteome in DNA damage recognition in the RUNX1-triggered pathway, and in the p53-regulation pathway. By applying scheduled multiple reaction monitoring using stable isotopically labeled peptide standards (MRM/SIS), we found a persistent increase in the content of the following proteins: PRAM1, CEPBP, RBPJ, and HIC1 in the HL-60 cell nuclear fraction during ATRA-induced granulocytic differentiation. In the case of STAT1, CASP3, PARP1, and PRKDC proteins, a transient increase in their content was observed at early time points (3–12 h) after the ATRA treatment. Obtained data on nuclear proteome composition and dynamics during granulocytic differentiation could be beneficial for the development of new treatment approaches for leukemias with the mutated p53 gene.

Mechanism underlying retinoic acid-dependent metamorphosis in the starfish

The evolution of the biphasic life cycle in marine invertebrates has attracted considerable interest in zoology. We recently provided evidence that retinoic acid (RA) is involved in the regulation of metamorphosis in starfish. It also functions in life cycle transitions of jellyfish (cnidaria). Thus, documenting the evolutionarily conserved role of RA in such transitions will help to trace the life cycle evolution of bilaterians and cnidarians. In this study, we examined the molecular mechanisms by which RA signaling is involved in the commencement of metamorphosis in starfish. First, we measured RA levels during the larval and metamorphosis stages by liquid chromatography-tandem mass spectrometry. We found that all-trans RA levels in the larval body are high before larvae acquire competence for metamorphosis, suggesting that the commencement of metamorphosis is not controlled by increased RA synthesis. Furthermore, the suppression of rar gene expression by TALEN-mediated gene knockout revealed that RA receptor (RAR) is essential for metamorphosis. These observations suggest that the initiation of metamorphosis is regulated at the level of synthesized RA to activate RAR. We discuss the divergence of ligand molecules and receptors during the evolution of life cycle regulation.

Retinoic Acid Receptor Alpha (RARα) in Macrophages Protects from Diet-Induced Atherosclerosis in Mice.

Retinoic acid signaling plays an important role in regulating lipid metabolism and inflammation. However, the role of retinoic acid receptor alpha (RARα) in atherosclerosis remains to be determined. In the current study, we investigated the role of macrophage RARα in the development of atherosclerosis. Macrophages isolated from myeloid-specific Rarα-/- (RarαMac-/-) mice showed increased lipid accumulation and inflammation and reduced cholesterol efflux compared to Rarαfl/fl (control) mice. All-trans retinoic acid (AtRA) induced ATP-binding cassette subfamily A member 1 (Abca1) and Abcg1 expression and cholesterol efflux in both RarαMac-/- mice and Rarαfl/fl mice. In Ldlr-/- mice, myeloid ablation of RARα significantly reduced macrophage Abca1 and Abcg1 expression and cholesterol efflux, induced inflammatory genes, and aggravated Western diet-induced atherosclerosis. Our data demonstrate that macrophage RARα protects against atherosclerosis, likely via inducing cholesterol efflux and inhibiting inflammation.

Hyperthermia promotes degradation of the acute promyelocytic leukemia driver oncoprotein ZBTB16/RARα.

The acute promyelocytic leukemia (APL) driver ZBTB16/RARα is generated by the t(11;17) (q23;q21) chromosomal translocation, which is resistant to combined treatment of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) or conventional chemotherapy, resulting in extremely low survival rates. In the current study, we investigated the effects of hyperthermia on the oncogenic fusion ZBTB16/RARα protein to explore a potential therapeutic approach for this variant APL. We showed that Z/R fusion protein expressed in HeLa cells was resistant to ATO, ATRA, and conventional chemotherapeutic agents. However, mild hyperthermia (42 °C) rapidly destabilized the ZBTB16/RARα fusion protein expressed in HeLa, 293T, and OCI-AML3 cells, followed by robust ubiquitination and proteasomal degradation. In contrast, hyperthermia did not affect the normal (i.e., unfused) ZBTB16 and RARα proteins, suggesting a specific thermal sensitivity of the ZBTB16/RARα fusion protein. Importantly, we found that the destabilization of ZBTB16/RARα was the initial step for oncogenic fusion protein degradation by hyperthermia, which could be blocked by deletion of nuclear receptor corepressor (NCoR) binding sites or knockdown of NCoRs. Furthermore, SIAH2 was identified as the E3 ligase participating in hyperthermia-induced ubiquitination of ZBTB16/RARα. In short, these results demonstrate that hyperthermia could effectively destabilize and subsequently degrade the ZBTB16/RARα fusion protein in an NCoR-dependent manner, suggesting a thermal-based therapeutic strategy that may improve the outcome in refractory ZBTB16/RARα-driven APL patients in the clinic.

Simultaneous HPLC Determination of Clindamycin Phosphate, Tretinoin, and Preservatives in Gel Dosage Form Using a Novel Stability-Indicating Method

The most well-known, effective medicines for acne therapy are clindamycin phosphate and tretinoin. For the first time, we have developed and validated a reversed-phase HPLC stability-indicating technique for the detection of clindamycin phosphate (CLP), tretinoin (TRN), and two preservatives, methylparaben (MP) and imidazolidinyl urea (IU), simultaneously in this work. Most of the chromatographic conditions in the present study were optimized to achieve better separation. The best separation results were obtained using gradient elution on a C-18 (250 × 4.6 mm), 5 µm column, with a mobile phase consisting of solution A (1 mL/L ortho-phosphoric acid in water) and solution B (methanol), at a flow rate of 1.0 mL/min, with UV detection at wavelengths of 200 nm and 353 nm. Standard parameters such as system suitability, precision, accuracy, specificity, robustness, linearity, range, detection limit, quantification limit, and reagent stability were used to validate the developed technique. According to the standards of the International Council for Harmonization, all of the experimental parameters were found to be within allowable bounds (ICH). The simultaneous concentrations of clindamycin phosphate, tretinoin, methylparaben, and imidazolidinyl urea in pharmaceutical formulations were successfully determined using the suggested approach. The proposed RP-HPLC method detected no interfering peaks in the chromatogram. We may conclude from the data that the new RP-HPLC method can be utilized in pharmaceutical laboratories to simultaneously assess clindamycin phosphate, tretinoin, and two preservatives, methylparaben and imidazolidinyl urea, for both qualitative and quantitative analyses.

All-Trans Retinoic Acid Effect on Candida albicans Growth and Biofilm Formation.

Candida albicans (C. albicans) is the most common fungal pathogen causing recurrent mucosal and life-threatening systemic infections. The ability to switch from yeast to hyphae and produce biofilm are the key virulence determinants of this fungus. In fact, Candida biofilms on medical devices represent the major risk factor for nosocomial bloodstream infections. Novel antifungal strategies are required given the severity of systemic candidiasis, especially in immunocompromised patients, and the lack of effective anti-biofilm treatments. Retinoids have gained attention recently due to their antifungal properties. Material and methods: The present study aimed at evaluating the in vitro effects of different concentrations (300 to 18.75 µg/mL) of All-trans Retinoic Acid (ATRA), a vitamin A metabolite, on Candida growth and biofilm formation. Results: ATRA completely inhibited the fungal growth, by acting as both fungicidal (at 300 µg/mL) and fungistatic (at 150 µg/mL) agent. Furthermore, ATRA was found to negatively affect Candida biofilm formation in terms of biomass, metabolic activity and morphology, in a dose-dependent manner, and intriguingly, its efficacy was as that of amphotericin B (AmB) (2–0.12 μg/mL). Additionally, transmission electron microscopy (TEM) analysis showed that at 300 μg/mL ATRA induced plasma membrane damage in Candida cells, confirming its direct toxic effect against the fungus. Conclusion: Altogether, the results suggest that ATRA has a potential for novel antifungal strategies aimed at preventing and controlling biofilm-associated Candida infections.

Cytotoxic Mechanism of Momilactones A and B against Acute Promyelocytic Leukemia and Multiple Myeloma Cell Lines.

Simple SummaryThough the anticancer potentiality of momilactones has been reported in several studies, their cytotoxic mechanism has not been comprehensively scrutinized. In this study, we investigated the cytotoxicity of momilactones A (MA) and B (MB) against acute promyelocytic leukemia (APL) HL-60 and multiple myeloma (MM) U266 cell lines. According to MTT results, MB and the mixture MAB (1:1, w/w) show a substantial inhibition on the cell viability of HL-60 and U266, with IC50 ranging from 4.49 to 5.59 µM. Besides, MB and MAB at 5 µM inhibit HL-60 cells through the regulations of relevant proteins to apoptosis-inducing factors (p-38, BCL-2, and caspase-3) and cell cycle arrest at G2 phase (p-38, CDK1, and cyclin B1). Meanwhile, these compounds enhance U266 apoptosis by altering p-38, BCL-2, and caspase-3 signaling pathways. Significantly, momilactones exhibit a minor effect on a non-cancerous cell line (MeT-5A), implying that they are promising candidates for developing novel anti-APL and anti-MM medicines.This is the first study clarifying the cytotoxic mechanism of momilactones A (MA) and B (MB) on acute promyelocytic leukemia (APL) HL-60 and multiple myeloma (MM) U266 cell lines. Via the MTT test, MB and the mixture MAB (1:1, w/w) exhibit a potent cytotoxicity on HL-60 (IC50 = 4.49 and 4.61 µM, respectively), which are close to the well-known drugs doxorubicin, all-trans retinoic acid (ATRA), and the mixture of ATRA and arsenic trioxide (ATRA/ATO) (1:1, w/w) (IC50 = 5.22, 3.99, and 3.67 µM, respectively). Meanwhile MB, MAB, and the standard suppressor doxorubicin substantially inhibit U266 (IC50 = 5.09, 5.59, and 0.24 µM, respectively). Notably, MB and MAB at 5 µM may promote HL-60 and U266 cell apoptosis by activating the phosphorylation of p-38 in the mitogen-activated protein kinase (MAPK) pathway and regulating the relevant proteins (BCL-2 and caspase-3) in the mitochondrial pathway. Besides, these compounds may induce G2 phase arrest in the HL-60 cell cycle through the activation of p-38 and disruption of CDK1 and cyclin B1 complex. Exceptionally, momilactones negligibly affect the non-cancerous cell line MeT-5A. This finding provides novel insights into the anticancer property of momilactones, which can be a premise for future studies and developments of momilactone-based anticancer medicines.

Subcellular Partitioning of Arsenic Trioxide Revealed by Label-Free Imaging.

Subcellular partitioning of therapeutic agents is highly relevant to their interactions with target molecules and drug efficacy, but studying subcellular partitioning is an enormous challenge. Here, we describe the application of nanoscale secondary ion mass spectrometry (NanoSIMS) analysis to define the subcellular pharmacokinetics of a cytotoxic chemotherapy drug, arsenic trioxide (ATO). We reasoned that defining the partitioning of ATO would yield valuable insights into the mechanisms underlying ATO efficacy. NanoSIMS imaging made it possible to define the intracellular fate of ATO in a label-free manner─and with high resolution and high sensitivity. Our studies of ATO-treated cells revealed that arsenic accumulates in the nucleolus. After prolonged ATO exposure, ∼40 nm arsenic- and sulfur-rich protein aggregates appeared in the cell nucleolus, nucleus, and membrane-free compartments in the cytoplasm, and our studies suggested that the partitioning of nanoscale aggregates could be relevant to cell survival. All-trans retinoic acid increased intracellular ATO levels and accelerated the nanoscale aggregate formation in the nucleolus. This study yielded fresh insights into the subcellular pharmacokinetics of an important cancer therapeutic agent and the potential impact of drug partitioning and pharmacokinetics on drug activity.

AML-156 Early Deaths in Patients With Newly Diagnosed Acute Promyelocytic Leukemia: A Single-Center Retrospective Study From a General Hospital

To evaluate the early death (ED; death within 30 days) rate and its causes in newly diagnosed acute promyelocytic leukemia (APL) patients. APL [t(15;17)] is a highly curable disease. EDs can be as high as 30% in a general hospital. We retrospectively analyzed new APL patients ≥18 years old treated at MHH between January 2009 and December 2021 using electronic medical records. Data included demographics, WBC, hemoglobin, platelet count on admission, coagulation parameters, presence/absence of disseminated intravascular coagulation, bone marrow or peripheral blood molecular analysis, immunohistochemistry, cytogenetics, Sanz score and risk stratification, timing of initiation of all trans retinoid acid (ATRA), complete response (CR) rate, major adverse events during induction, and ED rate. Twenty-five patients had newly diagnosed APL with flow cytometry, immunohistochemistry, cytogenetics, and molecular testing for t(15;17). Median age was 40 years (20-67 years), and 52% were men. Ten patients were white, 4 were African American, 7 were Hispanic, and 4 were Asian. By Sanz risk stratification, 5 patients had low-risk, 5 had intermediate-risk, and 15 had high-risk disease. Sixteen patients had bleeding diathesis: 8 with intracranial hemorrhage (ICH), 6 with gastrointestinal or genitourinary bleeding, and 1 each with retinal bleed and abdominal wall hematoma. Median time to ATRA initiation was 12 hours. High-risk patients (WBC>10,000) received idarubicin or gemtuzumab ozogomicin. Three patients died before evaluation. Twenty-two patients had a CR with ATRA and arsenic trioxide induction. Induction adverse events were febrile neutropenia (n=6), differentiation syndrome (n=5), and respiratory failure (mechanical ventilation, n=6); 12 required ICU admission, and 4 had acute kidney injury (1 requiring dialysis). Eight patients had ICH with 4 emergent craniotomies and 4 managed conservatively. ED occurred in 3 (12%) patients: 2 within 48 hours of admission and another between days 8 and 15. Two patients died of ICH and one from pseudomonas sepsis and multiorgan failure. Five patients developed thrombotic events: 2 each had pulmonary embolism and stroke and 1 had splenic and renal infarct. In 25 patients, the ED rate was low despite 8 patients presenting with ICH. Early diagnosis, timely administration of ATRA, coagulopathy correction, and critical and neurosurgery care can reduce ED in APL.

AML-173 Pseudotumor Cerebri (PTC) in Patients With Acute Leukemia (AL)

Pseudotumor cerebri (PTC) is characterized by headache, vision changes, and fundus papilledema. Primary PTC is often seen in obese women (childbearing age) and secondary with medications such as all-trans retinoic acid (ATRA). We analyze clinical presentation, and outcomes of PTC in patients with acute leukemia (AL) treated at a general hospital. Single-center retrospective study. We reviewed cases of AL patients with PTC at Memorial Hermann Hospital, Texas Medical Center between January 2013 and April 2022. Three (2.3%) of 127 patients (AML=85, APL=29, ALL= 13) had PTC. Fit non-APL patients received induction chemotherapy (IC) with purine analogs-cytarabine-anthracycline. Unfit patients received a hypomethylating agent and venetoclax. APL patients received IC with arsenic trioxide and ATRA. Patients suspected of having APL were started on ATRA, and discontinued with a negative PML-RARA FISH test. We describe the incidence, risk factors, clinical presentation, and outcomes of AL patients with PTC. Mean age was 42 years. Mean BMI was 42. All were white women. Two had AML, and one Philadelphia chromosome-positive ALL. AML patients received 3 doses of ATRA discontinued after negative PML-RARA FISH. One AML patient had PTC at presentation. The other developed PTC 3 months later. One AML patient had PTC 30 years before being treated for 6 months with acetazolamide; PTC recurred 3 months after her diagnosis. All patients had headaches, blurry vision, and papilledema with brain MRI showing optic sheath distension, globe flattening, and papilla cupping, all features suggestive of PTC. In two, the opening lumbar puncture pressures were elevated at 30 and 35 cm H2O. Cerebrospinal fluid cytology and flow cytometry were negative for leukemia. Two patients (AML=1, ALL=1) received intrathecal (IT) chemotherapy for CNS prophylaxis. All patient's symptoms improved with acetazolamide. LP done for IT chemotherapy helped to alleviate symptoms. No patient with APL (29 patients) developed PTC during treatment with ATRA. PTC is a rare diagnosis that can complicate the clinical course of AL patients. In addition to ATRA-induced PTC, clinicians should consider primary PTC, seen most often in morbidly obese women of childbearing age.

All-trans Retinoic Acid-incorporated Glycol Chitosan Nanoparticles Regulate Macrophage Polarization in Pg-LPS-Induced Inflammation.

The occurrence and development of inflammation are closely correlated to the polarization of macrophages. All-trans retinoic acid (ATRA) has been proven to promote the polarization of macrophages from M1 to M2, but this lacks an effective carrier to participate in the biological response. The present study aims to determine whether retinoic acid-incorporated glycol chitosan (RA-GC) nanoparticles can regulate macrophage polarization in Porphyromonas gingivalis-lipopolysaccharide (Pg-LPS)-induced inflammation. Mouse 264.7 cell lines were treated with 1 µg/mL Pg-LPS to induce inflammation. After the effects of ATRA and RA-GC on the activity of macrophages were detected by CCK-8 assay, cells induced with Pg-LPS were assigned to the blank control group (GC) nanoparticles without ATRA, and experimental groups (GC nanoparticles loaded with different concentrations of ATRA: 1, 10 and 100 µg/mL). The effects of RA-GC on inflammatory cytokines tumor necrosis factor-α, interleukin (IL)-10 and IL-12 in macrophages were detected by enzyme-linked immunosorbent assay (ELISA). Subsequently, the effects of GC nanoparticles loaded with/without ATRA on macrophage polarization in an inflammatory environment were detected by RT-PCR and Western blotting. The results revealed that RA-GC had no significant effect on macrophage activity. However, RA-GC could effectively inhibit the Pg-LPS-induced inflammatory factor expression in macrophages. Meanwhile, the experimental results confirmed that RA-GC could downregulate the expression of inducible nitric oxide synthase (iNOS) (a marker of M1 macrophages) and upregulate the expression of mannose receptor and Arginase-1 (a marker of M2 macrophages) in a dose-dependent manner. The present study confirms that RA-GC can promote the M2 polarization of macrophages in an inflammatory environment, and proposes this as a promising target for the clinical treatment of Pg-LPS-related diseases.

AML-434 Retrospective Review of Outcomes in Newly Diagnosed Leukemia Patients Aged 65 and Older When Admitted to the Hospital: A Single Center Experience

Acute leukemia patients have a diminished survival inversely proportional to their age. 5-year overall survival in younger AML patients is 50%, however reduced to <10% if age >70. Factors contributing include poor performance status, decreased response to induction therapy, increased treatment related mortality, unfavorable cytogenetics and secondary leukemia. Report observed characteristics and outcomes of elderly leukemia patients. Retrospective chart review of newly diagnosed acute myeloid leukemia (AML) patients >65 admitted from 7/1/2015 through 6/30/2021. Demographic information, classification, duration of hospital stay, blood products administered, treatment, discharge condition, 3 and 6 month remission, and survival data collected. Academic medical center. 149 patients identified. AML[n=130], acute promyelocytic leukemia (APL)[n=9], and acute leukemia not otherwise specified (AML-NOS)[n=10]. 97 patients treated. AML treatment: Induction therapy, daunorubicin and cytarabine (liposomal), or hypomethylating agent +/-venetoclax. APL treatment: all-trans retinoic acid (ATRA) +/- arsenic trioxide (ATO). One patient with AML-NOS received hypomethylator. Patients separated into three groups: <70[n=55], 70 to 74[n=52], and >75[n=60]. Percent of patients who did not receive any therapy increased as age group increased (21.8%, 32.7%, and 41.7%). Length of hospital stay, reflective of treatment, was greatest in the younger population (28 days, 17.6 days, and 15.3 days). 6-month survival 51% younger, 42.3% middle and 23.4% for eldest cohort. Treatment related mortality (TRM) including transitioning to hospice care increased as age increased (29%, 34% and 50%). 25/130 patients received induction chemotherapy. Nineteen patients were <70. The expected TRM for the younger cohort was 10.68% (1 - 41%) and 10.1% (1-20%) for elder cohort. The observed TRM was 10.5% in the younger cohort and 50% in the older cohort. Most of the eldest AML patients received a hypomethylating mono- or combination therapy. Nearly 50% of all AML were discharged home. The 6-month survival was 50% for younger, 26.8% for middle and 13.3% for eldest cohort. Nine APL patients were identified with 5 being in the eldest cohort. Only 3(33.3%) survived 6 months. None of the patients with AML-NOS were alive at 6 months. Acute leukemia in the elderly population remains a challenge with poor outcomes despite considering patient's age and performance status.

Zebrafish Model of Stickler Syndrome Suggests a Role for Col2a1a in the Neural Crest during Early Eye Development.

Most cases of Stickler syndrome are due to autosomal-dominant COL2A1 gene mutations leading to abnormal type II collagen. Ocular findings include axial eye lengthening with vitreal degeneration and early-onset glaucoma, which can result in vision loss. Although COL2A1 is a major player in cartilage and bone formation, its specific role in eye development remains elusive. We investigated the role of Col2a1a in neural crest migration and differentiation during early zebrafish eye development. In situ hybridization, immunofluorescence, live imaging, exogenous treatments [10 μM diethylaminobenzaldehyde (DEAB), 100 nM all-trans retinoic acid (RA) and 1–3% ethanol (ETOH)] and morpholino oligonucleotide (MO) injections were used to analyze wildtype Casper (roy−/−;nacre−/−), TgBAC(col2a1a::EGFP), Tg(sox10::EGFP) and Tg(foxd3::EGFP) embryos. Col2a1a colocalized with Foxd3- and Sox10-positive cells in the anterior segment and neural crest-derived jaw. Col2a1a expression was regulated by RA and inhibited by 3% ETOH. Furthermore, MO knockdown of Col2a1a delayed jaw formation and disrupted the ocular anterior segment neural crest migration of Sox10-positive cells. Interestingly, human COL2A1 protein rescued the MO effects. Altogether, these results suggest that Col2a1a is a downstream target of RA in the cranial neural crest and is required for both craniofacial and eye development.

AML-165 Clinical Outcomes of Patients With FLT3-Mutated Acute Myeloid Leukemia (AML): A Single-Center Retrospective Review

Fms-like tyrosine kinase-3 (FLT3) gene activating mutations predominate in AML, with internal tandem duplication (ITD) in 25 to 35% and point mutations in 5 to 7% of patients with normal karyotype. They associate with shorter relapse-free survival (RFS) and inferior outcome. To examine targeted FLT-3 mutations therapy during induction chemotherapy (IC) of AML. We reviewed all FLT3 mutated AML (both ITD and point mutations in the tyrosine kinase domain (TKD)) patients treated with FLT-3 targeted therapy during IC from March 2013 till December 2021. 28 patients (de novo AML=22, APL=6) with FLT3 mutated AML were identified. Fit patients received IC with fludarabine, cytarabine, and idarubicin (FIA) or IA (3+7 regimen). Older patients received hypomethylating agents (HMA) alone or with venetoclax (Ven). All received IC with FLT3 inhibitors (FLT3I, gilteritinib). All 6 APL patients achieved CR with arsenic trioxide (ATO) and all-trans-retinoic acid (ATRA). Analysis included overall response rate (ORR), complete response (CR), and relapse-free survival (RFS). 14 patients (50%) were men. Races included Whites (n=9), Blacks (n=6), Hispanics (n=8) and Others (n=5). The median age was 54 years (range, 20-68). 20 (71.40%) had ITD mutation, 4 (14.20%) had TKD mutation and 4 had both. 15 had NPM1 and 3 DNMT3A mutations. 14 patients had intermediate and 8 adverse risk AML (ELN). Of the AML patients 14 received standard, IC (FIA=8, IA=2, FIA+FLT3I=4), and 12 (85%) achieved CR. Unfit patients received (HMA alone=2, HMA+ Ven=4, HMA+Ven+FLT3I=1, HMA+FLT3I=1). The ORR was 60% with 50% CR. One FIA dead during IC. Three AML patients (10.70%) had allogeneic stem cell transplantations (ASCTs) and had remained in CR. Two non-ASCT were treated with HMA and one with FLT3I maintenance remaining in CR. 4 patients (14.20%) died in remission. Median relapse-free survival (RFS) was 360 days (range, 218-669). The median RFS for non-ASCT patients was 240 days (range, 195-405). Historically RFS in FLT-3 AML is 120 days. IC with FLT3I is highly effective with low induction mortality. Response duration was shorter in the non-ASCT group. In FLT-3 AML ASCT ineligible patients, maintenance therapy may reduce relapse risk.

Effect of All-trans Retinoic Acid on Panniculus Carnosus Muscle Regeneration in Fetal Mouse Wound Healing.

Background:The dermal panniculus carnosus (PC) muscle is critical for wound contraction in lower mammals and is a useful model of muscle regeneration owing to its high cellular metabolic turnover. During wound healing in mice, skin structures, including PC, are completely regenerated up to embryonic day (E) 13, but PC is only partially regenerated in fetuses or adult animals after E14. Nevertheless, the mechanisms underlying wound repair for complete regeneration in PC have not been fully elucidated. We hypothesized that retinoic acid (RA) signaling, which is involved in muscle differentiation, regulates PC regeneration.Methods:Surgical injury was induced in ICR mice on E13 and E14. RA receptor alpha (RARα) expression in tissue samples from embryos was evaluated using immunohistochemistry and reverse transcription-quantitative polymerase chain reaction. To evaluate the effects of RA on PC regeneration, beads soaked in all-trans RA (ATRA) were implanted in E13 wounds, and tissues were observed. The effects of RA on myoblast migration were evaluated using a cell migration assay.Results:During wound healing, RARα expression was enhanced at the cut surface in PCs of E13 wounds but was attenuated at the cut edge of E14 PCs. Implantation of ATRA-containing beads inhibited PC regeneration on E13 in a concentration-dependent manner. Treatment of myoblasts with ATRA inhibited cell migration.Conclusions:ATRA inhibits PC regeneration, and decreased RARα expression in wounds after E14 inhibits myoblast migration. Our findings may contribute to the development of therapies to promote complete wound regeneration, even in the muscle.

Combination Treatment of Retinoic Acid Plus Focal Adhesion Kinase Inhibitor Prevents Tumor Growth and Breast Cancer Cell Metastasis.

All-trans retinoic acid (RA), the primary metabolite of vitamin A, controls the development and homeostasis of organisms and tissues. RA and its natural and synthetic derivatives, both known as retinoids, are promising agents in treating and chemopreventing different neoplasias, including breast cancer (BC). Focal adhesion kinase (FAK) is a crucial regulator of cell migration, and its overexpression is associated with tumor metastatic behavior. Thus, pharmaceutical FAK inhibitors (FAKi) have been developed to counter its action. In this work, we hypothesize that the RA plus FAKi (RA + FAKi) approach could improve the inhibition of tumor progression. By in silico analysis and its subsequent validation by qPCR, we confirmed RARA, SRC, and PTK2 (encoding RARα, Src, and FAK, respectively) overexpression in all breast cells tested. We also showed a different pattern of genes up/down-regulated between RA-resistant and RA-sensitive BC cells. In addition, we demonstrated that both RA-resistant BC cells (MDA-MB-231 and MDA-MB-468) display the same behavior after RA treatment, modulating the expression of genes involved in Src-FAK signaling. Furthermore, we demonstrated that although RA and FAKi administered separately decrease viability, adhesion, and migration in mammary adenocarcinoma LM3 cells, their combination exerts a higher effect. Additionally, we show that both drugs individually, as well as in combination, induce the expression of apoptosis markers such as active-caspase-3 and cleaved-PARP1. We also provided evidence that RA effects are extrapolated to other cancer cells, including T-47D BC and the human cervical carcinoma HeLa cells. In an orthotopic assay of LM3 tumor growth, whereas RA and FAKi administered separately reduced tumor growth, the combined treatment induced a more potent inhibition increasing mice survival. Moreover, in an experimental metastatic assay, RA significantly reduced metastatic lung dissemination of LM3 cells. Overall, these results indicate that RA resistance could reflect deregulation of most RA-target genes, including genes encoding components of the Src-FAK pathway. Our study demonstrates that RA plays an essential role in disrupting BC tumor growth and metastatic dissemination in vitro and in vivo by controlling FAK expression and localization. RA plus FAKi exacerbate these effects, thus suggesting that the sensitivity to RA therapies could be increased with FAKi coadministration in BC tumors.