Retinoid Agonists in the Targeting of Heterotopic Ossification

Retinoids are metabolic derivatives of vitamin A and regulate the function of many tissues and organs both prenatally and postnatally. Active retinoids, such as all trans-retinoic acid, are produced in the cytoplasm and then interact with nuclear retinoic acid receptors (RARs) to up-regulate the transcription of target genes. The RARs can also interact with target gene response elements in the absence of retinoids and exert a transcriptional repression function. Studies from several labs, including ours, showed that chondrogenic cell differentiation and cartilage maturation require (i) the absence of retinoid signaling and (ii) the repression function by unliganded RARs. These and related insights led to the proposition that synthetic retinoid agonists could thus represent pharmacological agents to inhibit heterotopic ossification (HO), a process that recapitulates developmental skeletogenesis and involves chondrogenesis, cartilage maturation, and endochondral ossification. One form of HO is acquired and is caused by injury, and another severe and often fatal form of it is genetic and occurs in patients with fibrodysplasia ossificans progressiva (FOP). Mouse models of FOP bearing mutant ACVR1R206H, characteristic of most FOP patients, were used to test the ability of the retinoid agonists selective for RARα and RARγ against spontaneous and injury-induced HO. The RARγ agonists were found to be most effective, and one such compound, palovarotene, was selected for testing in FOP patients. The safety and effectiveness data from recent and ongoing phase II and phase III clinical trials support the notion that palovarotene may represent a disease-modifying treatment for patients with FOP. The post hoc analyses showed substantial efficacy but also revealed side effects and complications, including premature growth plate closure in some patients. Skeletally immature patients will need to be carefully weighed in any future regulatory indications of palovarotene as an important therapeutic option in FOP.

Download Full-text

Transcriptional repression of microRNA genes by PML-RARA increases expression of key cancer proteins in acute promyelocytic leukemia

Blood ◽

10.1182/blood-2008-05-158139 ◽

2009 ◽

Vol 113 (2) ◽

pp. 412-421 ◽

Cited By ~ 77

Author(s):

Anne Saumet ◽

Guillaume Vetter ◽

Manuella Bouttier ◽

Elodie Portales-Casamar ◽

Wyeth W. Wasserman ◽

...

Keyword(s):

Retinoic Acid ◽

Acute Promyelocytic Leukemia ◽

Transcriptional Repression ◽

Promyelocytic Leukemia ◽

Mirna Biogenesis ◽

Cell Physiology ◽

Small Noncoding Rnas ◽

Mirna Genes ◽

All Trans Retinoic Acid ◽

Key Aspects

Abstract Micro(mi)RNAs are small noncoding RNAs that orchestrate many key aspects of cell physiology and their deregulation is often linked to distinct diseases including cancer. Here, we studied the contribution of miRNAs in a well-characterized human myeloid leukemia, acute promyelocytic leukemia (APL), targeted by retinoic acid and trioxide arsenic therapy. We identified several miRNAs transcriptionally repressed by the APL-associated PML-RAR oncogene which are released after treatment with all-trans retinoic acid. These coregulated miRNAs were found to control, in a coordinated manner, crucial pathways linked to leukemogenesis, such as HOX proteins and cell adhesion molecules whose expressions are thereby repressed by the chemotherapy. Thus, APL appears linked to transcriptional perturbation of miRNA genes, and clinical protocols able to successfully eradicate cancer cells may do so by restoring miRNA expression. The identification of abnormal miRNA biogenesis in cancer may therefore provide novel biomarkers and therapeutic targets in myeloid leukemias.

Download Full-text

Mutation of Cellular Retinoic Acid-Binding Protein-II (Crabp-II) Does Not Account for Resistance to All-Trans Retinoic Acid (ATRA) in Relapse Acute Promyelocytic Leukemia (APL).

Blood ◽

10.1182/blood.v104.11.2081.2081 ◽

2004 ◽

Vol 104 (11) ◽

pp. 2081-2081

Author(s):

Binu-John Sankoorikal ◽

Da-Cheng Zhou ◽

Peter H. Wiernik ◽

Robert E. Gallagher

Keyword(s):

Retinoic Acid ◽

Target Genes ◽

Retinoic Acid Receptor ◽

Treated Patient ◽

Coding Region ◽

Treatment Regimens ◽

All Trans Retinoic Acid ◽

Negative Role ◽

Multiple Relapse ◽

Crabp Ii

Abstract An increase in CRABP-II has frequently been invoked as a cause of resistance to ATRA in APL due to cytoplasmic sequestration and catabolism of ATRA. However, recent evidence indicates that CRABP-II has a positive rather than a negative role in ATRA activity by facilitating delivery of ATRA to retinoic acid receptor-alpha (RARα) associated with ATRA target genes in the cell nucleus or/and by serving as a co-activator of RARα-regulated transcription. This implies that if CRABP-II has a role in the development of ATRA resistance in APL, this would more likely occur through a deficiency rather than from an increase in CRABP-II. We previously reported that CRABP-II is constitutively expressed at similar levels in pretreatment and relapse APL cells (Zhou, et al, Cancer Res58, 5770, 1998), suggesting that putative CRABP-II deficiency is not due to the loss of CRABP-II expression. To investigate the alternative possibility that CRABP-II deficiency might arise through inactivating mutations, we sequenced the entire coding region of CRABP-II from 18 cases of APL who had relapsed from prior ATRA-containing treatment regimens. In 8 cases RNA was transcribed by reverse transcriptase to cDNA and amplified by polymerase chain reaction (PCR), using primers anchored in the 5′ and 3′ untranslated region of mRNA; in 10 cases, genomic DNA was PCR amplified for sequence analysis, using primers anchored in the introns between the 4 exons of the gene. No CRABP-II mutations were identified. The samples tested included 11 first-relapse cases, 2 of whom were refractory to reinduction therapy with intravenous liposomal-ATRA, and 7 multiple relapse cases, all of whom were clinically refractory to ATRA and had, additionally, relapsed from arsenic trioxide therapy. Also, no mutations were found in 3 APL patients who had relapsed from chemotherapy-induced remissions or in 3 APL cell lines (NB4, UF-1 and AP-1060). Two heterozygous base substitutions were incidentally identified in CRABP-II intron 2 in a chemotherapy-only treated patient. These results indicate that CRABP-II mutations rarely, if ever, contribute to ATRA-resistance or disease relapse in APL.

Download Full-text

RTP801 Is a Novel Retinoic Acid Responsive Gene Possibly Involved in Myeloid Differentiation.

Blood ◽

10.1182/blood.v106.11.2715.2715 ◽

2005 ◽

Vol 106 (11) ◽

pp. 2715-2715

Author(s):

Sigal Gery ◽

Dorothy J. Park ◽

Peter T. Vuong ◽

H. Phillip Koeffler

Keyword(s):

Retinoic Acid ◽

Target Gene ◽

Target Genes ◽

Myeloid Cell ◽

Representational Difference Analysis ◽

Dependent Manner ◽

All Trans Retinoic Acid ◽

Myeloid Cell Line ◽

Specific Protease ◽

Stress Signals

Abstract Retinoic acid (RA) promotes terminal differentiation of both normal hematopoietic cells and acute promyelocytic leukemia (APL) blasts by transcriptional regulation of myeloid genes. To identify additional RA target genes, we used representational difference analysis (RDA) with RNA derived from a PML/RARα inducible U937 myeloid cell line. From this screen we identified a novel early responsive RA target gene, RTP801 (REDD1). Recent studies showed that RTP801 is a critical transducer of several cellular stress signals, including hypoxia and energy depletion, through the TSC-mTOR pathway. We show that All-trans retinoic acid (ATRA) induces RTP801 mRNA in AML cell lines in a dose- and time-dependent manner. ATRA regulation of RTP801 is direct and does not require protein synthesis. Inhibition of endogenous RTP801 in U937 cells by siRNA abrogates ATRA-induced dephosphorylatioin of 4E-BP1, a key mTOR substrate. Overexpression of RTP801 in these cells results in growth arrest and apoptosis. RTP801 is differently expressed during maturation of normal CD34+ cells, suggesting it is involved in this process. We performed a yeast two-hybrid screen using a leucocyte cDNA library and identified the myeloid-specific protease, neutrophil elastase, as a binding partner of RTP801. Taken together, RTP801 is a novel ATRA target gene possibly involved in ATRA-induced differentiation of myeloid cells.

Download Full-text

Cooperative Action of 1alpha,25-Dihydroxyvitamin D3 and Retinoic Acid in NB4 Acute Promyelocytic Leukemia Cell Differentiation Is Transcriptionally Controlled.

Blood ◽

10.1182/blood.v106.11.4247.4247 ◽

2005 ◽

Vol 106 (11) ◽

pp. 4247-4247

Author(s):

Jean-Noel Bastie ◽

Nicole Balitrand ◽

Isabelle Guillemot ◽

Christine Chomienne ◽

Laurent Delva

Keyword(s):

Retinoic Acid ◽

Transcriptional Activity ◽

Target Genes ◽

Leukemia Cell ◽

Leukemic Cells ◽

Dihydroxyvitamin D3 ◽

Nb4 Cells ◽

Cooperative Action ◽

Trans Retinoic Acid ◽

All Trans Retinoic Acid

Abstract All-trans-retinoic acid (RA) and 1alpha,25-dihydroxyvitamin D3 (1,25D3) are involved in the control of hematopoiesis and have been suggested to play a role in cellular differentiation and are as such potent inducers of differentiation of myeloid leukemia cells. In this study, we have shown that in promyelocytic NB4 cells, addition of 1,25D3 enhances terminal granulocytic RA-dependent differentiation concomitant with the enhanced activation of the RA-transcriptional activity through an RARbeta promoter. By EMSA and ChIP assays, we further demonstrate that while both VDR and RAR are bound to the RARbeta promoter in NB4 cells, addition of 1,25D3 increases VDR binding to this promoter while that of RA induces the release of VDR and increases the binding of RAR. Thus, contrary to normal myeloid cells, 1,25D3 does not act as a transrepressor of RA-transcriptional activity in leukemic cells suggesting that transcriptional regulation of RA-target genes may be modified in malignant cells. In promyelocytic leukemic cells the combination of 1,25D3 and RA results in both enhanced transactivation and differentiation.

Download Full-text

Phase III Trial of All-Trans Retinoic Acid (ATRA) vs Daunorubicin (D) and Cytosine Arabinoside (A) as Induction Therapy and ATRA vs Observation as Maintenance Therapy for Children with Newly Diagnosed Acute Promyelocytic Leukemia (APL).

Blood ◽

10.1182/blood.v106.11.894.894 ◽

2005 ◽

Vol 106 (11) ◽

pp. 894-894

Author(s):

John Gregory ◽

Haesook Kim ◽

Todd Alonzo ◽

Rob Gerbing ◽

Angela Ogden ◽

...

Keyword(s):

Retinoic Acid ◽

Maintenance Therapy ◽

Pseudotumor Cerebri ◽

Phase Iii ◽

Phase Iii Trial ◽

All Trans Retinoic Acid ◽

Female Predominance ◽

One Year ◽

To Receive ◽

Salvage Rate

Abstract Between April 1992 and February 1995, 71 children with locally diagnosed APL were enrolled on the national trial (ECOG E2491) to test ATRA during induction and maintenance (MAINT). Induction consisted of either ATRA, 45 mg/m2/d orally, or 1–2 cycles of D, 45 mg/m2/d IV bolus days 1–3, plus A, 100 mg/m2/day by continuous intravenous (IV) infusion days 1–7. All patients (pts) achieving complete remission (CR) were scheduled to receive two cycles of consolidation chemotherapy consisting of one cycle the same as induction followed by A, 2 gm/m2 IV over one hour every 12 hours days 1–4, plus D, 45 mg/m2/d IV bolus days 1–2. Pts on both arms were then randomized to receive either MAINT ATRA, 45 mg/m2/d orally for one year, or observation (OBS). Fifty-three children with the (15;17) translocation or centrally reviewed M3 FAB APL are the subject of this report. These patients were aged 1–18 years (median 12 years; only 2 < 2 yrs). A female predominance was noted (60% female). The distribution by race was: White 35, African American 7, Hispanic 8, Asian 2, and Filipino 1 patient. No extramedullary disease was proven at diagnosis. Twenty-seven patients were reported to have bleeding symptoms at diagnosis. The median WBC at study entry was 3.2 (4.2 for the DA arm, 2.6 for the ATRA arm). Only one patient was noted to have the M3v subtype. Twenty-seven pts were treated on the ATRA induction arm and 26 on the DA induction arm. A CR rate of 70% was obtained (ATRA CR 81%, DA CR 58%, P=0.08) after Induction and 3 additional patients achieved a CR after cross-over to DA (overall CR=75%). The 3 year DFS from achieving CR was 49% (DA 46%, ATRA 51%, P=0.33). Thirty-three patients reached maintenance therapy after CR- 16 in the OBS arm and 17 in the MAINT ATRA arm. The 3 year DFS from the start of MAINT was 48%( MAINT ATRA 75%, OBS 19%, P=0.0001). The 5 year OS was 68% (DA 62%, ATRA 73%, P=0.33). Induction toxicity data for 53 patients treated on this study included: four patients had a Grade III/IV hemorrhage during induction (DA 3, ATRA 1), intracranial hemorrhage(ICH) in 3, retinoic acid syndrome (RAS) in 2, pseudotumor cerebri definite in 2 and probable in 6, typhlitis in 2, and pancreatitis in 1. Four lethal toxicities occurred including two from ICH and one each from infection and RAS. (DA 3, ATRA 1) In conclusion, 1) the outcome for children with APL is excellent when treated with ATRA and anthracycline-based induction; 2) ATRA as maintenance resulted in a statistically significant advantage in DFS; 3) the salvage rate for relapsed patients appeared promising.

Download Full-text

Ligands and DNA in the allosteric control of retinoid receptors function

Essays in Biochemistry ◽

10.1042/ebc20200168 ◽

2021 ◽

Author(s):

Pierre Germain ◽

Natacha Rochel ◽

William Bourguet

Keyword(s):

Retinoic Acid ◽

Dna Sequences ◽

Target Genes ◽

Retinoic Acid Receptor ◽

Signal Propagation ◽

Retinoid Receptors ◽

Allosteric Control ◽

Current State ◽

All Trans Retinoic Acid ◽

Structural Mechanisms

Abstract Retinoids are a family of compounds that include both vitamin A (all-trans retinol) and its naturally occurring metabolites such as retinoic acids (e.g. all-trans retinoic acid) as well as synthetic analogs. They are critically involved in the regulation of a wide variety of essential biological processes, such as embryogenesis and organogenesis, apoptosis, reproduction, vision, and the growth and differentiation of normal and neoplastic cells in vertebrates. The ability of these small molecules to control the expression of several hundred genes through binding to nuclear ligand-dependent transcription factors accounts for most of their functions. Three retinoic acid receptor (RARα,β,γ) and three retinoid X receptor (RXRα,β,γ) subtypes form a variety of RXR–RAR heterodimers that have been shown to mediate the pleiotropic effects of retinoids through the recruitment of high-molecular weight co-regulatory complexes to response-element DNA sequences found in the promoter region of their target genes. Hence, heterodimeric retinoid receptors are multidomain entities that respond to various incoming signals, such as ligand and DNA binding, by allosteric structural alterations which are the basis of further signal propagation. Here, we provide an overview of the current state of knowledge with regard to the structural mechanisms by which retinoids and DNA response elements act as allosteric effectors that may combine to finely tune RXR–RAR heterodimers activity.

Download Full-text

All-trans-Retinoic Acid Represses Obesity and Insulin Resistance by Activating both Peroxisome Proliferation-Activated Receptor β/δ and Retinoic Acid Receptor

Molecular and Cellular Biology ◽

10.1128/mcb.01742-08 ◽

2009 ◽

Vol 29 (12) ◽

pp. 3286-3296 ◽

Cited By ~ 207

Author(s):

Daniel C. Berry ◽

Noa Noy

Keyword(s):

Insulin Resistance ◽

Retinoic Acid ◽

Target Genes ◽

Retinoic Acid Receptor ◽

Biological Activities ◽

In Vivo Studies ◽

Peroxisome Proliferation ◽

The Metabolic Syndrome ◽

All Trans Retinoic Acid

ABSTRACT Many biological activities of all-trans-retinoic acid (RA) are mediated by the ligand-activated transcription factors termed retinoic acid receptors (RARs), but this hormone can also activate the nuclear receptor peroxisome proliferation-activated receptor β/δ (PPARβ/δ). We show here that adipocyte differentiation is accompanied by a shift in RA signaling which, in mature adipocytes, allows RA to activate both RARs and PPARβ/δ, thereby enhancing lipolysis and depleting lipid stores. In vivo studies using a dietary-induced mouse model of obesity indicated that onset of obesity is accompanied by downregulation of adipose PPARβ/δ expression and activity. RA treatment of obese mice induced expression of PPARβ/δ and RAR target genes involved in regulation of lipid homeostasis, leading to weight loss and improved insulin responsiveness. RA treatment also restored adipose PPARβ/δ expression. The data indicate that suppression of obesity and insulin resistance by RA is largely mediated by PPARβ/δ and is further enhanced by activation of RARs. By targeting two nuclear receptors, RA may be a uniquely efficacious agent in the therapy and prevention of the metabolic syndrome.

Download Full-text

Synergy between all-trans retinoic acid and tumor necrosis factor pathways in acute leukemia cells

Blood ◽

10.1182/blood-2002-09-2725 ◽

2003 ◽

Vol 102 (1) ◽

pp. 237-245 ◽

Cited By ~ 47

Author(s):

Michael Witcher ◽

Douglas T. Ross ◽

Caroline Rousseau ◽

Leslie Deluca ◽

Wilson H. Miller

Keyword(s):

Retinoic Acid ◽

Tumor Necrosis Factor ◽

Dna Binding ◽

Cell Line ◽

Tumor Necrosis ◽

Target Genes ◽

Trans Retinoic Acid ◽

All Trans Retinoic Acid ◽

Necrosis Factor

Abstract The nuclear receptor ligand all-trans retinoic acid (ATRA) causes dramatic terminal differentiation of acute promyelocytic leukemia (APL) cells in vitro and in patients, but it is less active in other malignancies. However, downstream mediators of the effects of ATRA are not well understood. We used a cDNA microarray to search for ATRA-regulated genes in the APL cell line NB4 and found that ATRA regulated several members of the tumor necrosis factor (TNF) pathway. Here we show that TNF can synergize with ATRA to induce differentiation, showing monocytic characteristics more typical of differentiation mediated by TNF than by ATRA. ATRA and TNF can also induce differentiation of the non-APL cell line U937. Underlying this response was an increase in TNF-induced nuclear factor-κB (NF-κB) DNA binding within 2 hours in the presence of ATRA and activation of NF-κB DNA binding and transcriptional activity in response to ATRA alone within 48 hours of ATRA treatment. Furthermore, we found a synergistic induction of the NF-κB target genes BCL-3, Dif-2, and TNF receptor 2 (TNFR2) in response to the combination of TNF and ATRA. These genes have been previously shown to play a role in TNF signaling, and amplification of such genes may represent a mechanism whereby TNF and ATRA can act synergistically. We propose that ATRA can prime cancer cells for differentiation triggered by TNF and suggest that targeting the TNF pathway in combination with ATRA may represent a novel route to treat leukemias. (Blood. 2003;102:237-245)

Download Full-text

Phase III study of all-trans retinoic acid in previously untreated patients 61 years or older with acute myeloid leukemia

Leukemia ◽

10.1038/sj.leu.2403528 ◽

2004 ◽

Vol 18 (11) ◽

pp. 1798-1803 ◽

Cited By ~ 115

Author(s):

R F Schlenk ◽

◽

S Fröhling ◽

F Hartmann ◽

J Th Fischer ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Retinoic Acid ◽

Myeloid Leukemia ◽

Phase Iii ◽

Trans Retinoic Acid ◽

All Trans Retinoic Acid ◽

Phase Iii Study ◽

Acute Myeloid

Download Full-text

Nuclear and extranuclear effects of vitamin A

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2014-0522 ◽

2015 ◽

Vol 93 (12) ◽

pp. 1065-1075 ◽

Cited By ~ 20

Author(s):

Madina Iskakova ◽

Mikhail Karbyshev ◽

Aleksandr Piskunov ◽

Cécile Rochette-Egly

Keyword(s):

Retinoic Acid ◽

Vitamin A ◽

Nuclear Receptors ◽

Target Genes ◽

Dependent Manner ◽

Active Metabolites ◽

Trans Retinoic Acid ◽

All Trans Retinoic Acid ◽

Cell Growth And Differentiation ◽

Per Se

Vitamin A or retinol is a multifunctional vitamin that is essential at all stages of life from embryogenesis to adulthood. Up to now, it has been accepted that the effects of vitamin A are exerted by active metabolites, the major ones being 11-cis retinal for vision, and all trans-retinoic acid (RA) for cell growth and differentiation. Basically RA binds nuclear receptors, RARs, which regulate the expression of a battery of target genes in a ligand dependent manner. During the last decade, new scenarios have been discovered, providing a rationale for the understanding of other long-noted but not explained functions of retinol. These novel scenarios involve: (i) other nuclear receptors such as PPAR β/δ, which regulate the expression of other target genes with other functions; (ii) extranuclear and nontranscriptional effects, such as the activation of kinases, which phosphorylate RARs and other transcription factors, thus expanding the list of the RA-activated genes; (iii) finally, vitamin A is active per se and can work as a cytokine that regulates gene transcription by activating STRA6. New effects of vitamin A and RA are continuously being discovered in new fields, revealing new targets and new mechanisms thus improving the understanding the pleiotropicity of their effects.

Download Full-text