Combination Of All-trans Retinoic Acid Research Articles

All-Trans Retinoic Acid Promotes M2 Macrophage Polarization in Vitro by Activating the p38MAPK/STAT6 Signaling Pathway

ABSTRACT Background M2-type macrophages are inflammation-suppressing cells that are differentiated after induction by cytokines such as IL-4 or IL-13, which play an important regulatory role in inflammation and influence the regression of inflammation-related diseases. All-trans retinoic acid (ATRA) has an important role in suppressing immune-mediated inflammatory responses but the effect and underlying mechanism of ATRA on the polarization of M2 macrophages remains unclear. Methods Macrophages were isolated from peritoneal wash fluid, and IL-4 (20 ng/mL) was used to construct a m2-type macrophage polarization model. The model was incubated with different concentrations of ATRA (15 µg/ml, 30 µg/ml, 45 µg/ml) for 24 h, and pretreated macrophages with p38MAPKα inhibitor SB202190 (20 μM). MTT, Trypan blue staining, Annexin V-PE/7-AAD staining, flow cytometry, real-time PCR and western blotting were used to investigate the effect and mechanism of ATRA on the polarization of M2 macrophages. Results Compared with the IL-4 group, the proportion of F4/80+CD206+ M2-type macrophages was significantly higher in the ATRA group (P < 0.01). mRNA and protein expression levels of Arg-1, IL-10 and TGF-β1 were as significantly higher (P < 0.01) in the ATRA group as phosphorylation levels of STAT6 and p38MAPK (P < 0.01). After pretreatment with the addition of the inhibitor SB202190, M2-type macrophages proportion and their associated factors expression were significantly (P < 0.01) reduced, as compared with those in the ATRA group, but they were comparable (P > 0.05) with the IL-4 group. Conclusion The combination of ATRA and IL-4 activated the p38MAPK/STAT6-signaling pathway to promote polarization of M2 macrophages.

Compound Nanoemulsion Combined with Differentiation/Cytotoxicity Drugs for Modulating Breast Cancer Stemness.

Breast cancer stem cells (BCSCs) are the culprit of triple-negative breast cancer invasiveness and are heterogeneous. It is recognized that the combination of chemotherapy and differentiation therapy for killing BCSCs and non-BCSCs simultaneously is a reliable strategy. In this study, an oil-in-water nanoemulsion was prepared by high-pressure homogenization with coencapsulation of all-trans retinoic acid (ATRA) and doxorubicin (DOX). The preparation process was simple, and the production was easy to scale up. The particle size of the nanoemulsion was 127.2 ± 2.0 nm. Cellular toxicity assay showed that the composite index of the ATRA and DOX was less than 1 and exhibited a fine combined effect. In vivo antitumor efficacy showed that the compound nanoemulsion could reduce the proportion of BCSCs to 1.18% by inhibiting the expression of Pin1. In addition, the combination of ATRA and DOX could reduce the cardiotoxicity of DOX and had higher safety. Hopefully, this work can provide a new insight into developing pharmaceutically acceptable technology for treating BCSCs.

The immunomodulatory effects of all-trans retinoic acid and docosahexaenoic acid combination treatment on the expression of IL-2, IL-4, T-bet, and GATA3 genes in PBMCs of multiple sclerosis patients

ABSTRACT Objectives Multiple sclerosis (MS) is a potentially disabling autoimmune disease of the central nervous system. Neither the pathogenesis nor the effectiveness of treatment of MS has been fully understood. This in vitro trial evaluated the beneficial immunomodulatory effects of single and combined treatments of all-trans retinoic acid (ATRA) and docosahexaenoic acid (DHA) on the peripheral blood mononuclear cells (PBMCs) of relapsing-remitting MS (RRMS) patients who were receiving interferon beta (IFN-β). Methods The PBMCs of 15 RRMS patients were isolated, cultured, and treated with single and combined treatments of ATRA and DHA. The expressions of IL-2, IL-4, T-bet, and GATA3 genes were evaluated using real-time PCR. Results The results showed that a single treatment of ATRA could significantly suppress the gene expression of the pro-inflammatory cytokine, IL-2 (P < 0.05), and related transcription factor, T-bet (P < 0.001). The gene expression level of the anti-inflammatory cytokine, IL-4, and its transcription factor, GATA3, were not significantly changed. The expression of IL-2 and T-bet genes was significantly decreased in combination treatments of ATRA and DHA (P < 0.001). Significant suppression of IL-2 and T-bet (P < 0.001) was observed in ATRA and DHA combination therapy with half doses of their single treatment, which suggested a synergistic effect of these components. Discussion Co-administration of vitamin A and DHA, an omega-3 fatty acid derivative, may exert a synergistic effect in modulating the immune system in MS patients; however, more studies are needed to evaluate the exact effects and mechanism of their actions on the immune cells.

Remodeling of imbalanced extracellular matrix homeostasis for reversal of pancreatic fibrosis

Pancreatic fibrosis is mainly manifested by imbalance in extracellular matrix (ECM) homeostasis due to excessive deposition of collagen in pancreas by activated pancreatic stellate cells (PSCs). Recently, some drugs have exhibited therapeutic potentials for the treatment of pancreatic fibrosis; however, currently, no effective clinical strategy is available to remodel imbalanced ECM homeostasis because of inferior targeting abilities of drugs and collagen barriers that hinder the efficient delivery of drugs. Herein, we design and prepare collagen-binding peptide (CBP) and collagenase I co-decorated dual drug-loaded lipid nanoparticles (named AT-CC) for pancreatic fibrosis therapy. Specifically, AT-CC can target fibrotic pancreas via the CBP and degrade excess collagen by the grafted collagenase I, thereby effectively delivering all-trans-retinoic acid (ATRA) and ammonium tetrathiomolybdate (TM) into pancreas. The released ATRA can reduce collagen overproduction by inhibiting the activation of PSCs. Moreover, the released TM can restrain lysyloxidase activation, consequently reducing collagen cross-linking. The combination of ATRA and TM represses collagen synthesis and reduces collagen cross linkages to restore ECM homeostasis. The results of this research suggest that AT-CC is a safe and efficient collagen-targeted degradation drug-delivery system for reversing pancreatic fibrosis. Furthermore, the strategy proposed herein will offer an innovative platform for the treatment of chronic pancreatitis.

Effect of IL-27, Teriflunomide and Retinoic Acid and Their Combinations on CD4+ T Regulatory T Cells—An In Vitro Study

The principal goal of the study was to verify the concept of pharmacological induction of Foxp3+CD25+CD4+ T regulatory (Treg) cells which will additionally be characterized by a highly suppressive phenotype, i.e., by extensive CD25 and CD39 expression and IL-10 and TGF-β production. Stimulated and unstimulated murine lymphocytes were exposed to IL-27, teriflunomide (TER), and all trans retinoic acid (ATRA) alone and to their combinations. The study demonstrated that: (a) IL-27 alone induced CD39 expression on Treg cells and the generation of Tr1 cells; (b) TER alone induced Foxp3-expressing CD4+ T cells and up-regulated density of CD25 on these cells; TER also induced the ability of Treg cells to TGF-β production; (c) ATRA alone induced CD39 expression on Treg cells. The experiments revealed a strong superadditive effect between IL-27 and ATRA with respect to increasing CD39 expression on Treg cells. Moreover, IL-27 and ATRA in combination, but not alone, induced the ability of Treg cells to IL-10 production. However, the combination of IL-27, TER, and ATRA did not induce the generation of Treg cell subset with all described above features. This was due to the fact that TER abolished all listed above desired effects induced by IL-27 alone, ATRA alone, and their combination. IL-27 alone, ATRA alone, and their combination affected TER-induced effects to a lesser extent. Therefore, it can be concluded that in the aspect of pharmacological induction of Treg cells with a highly suppressive phenotype, the triple combination treatment with TER, IL-27, and ATRA does not provide any benefits over TER alone or dual combination including IL-27 and ATRA.

An effective and chemotherapy-free strategy of all-trans retinoic acid and arsenic trioxide for acute promyelocytic leukemia in all risk groups (APL15 trial)

The combination of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) has been demonstrated to have comparable effectiveness or better to ATRA and chemotherapy (CHT) in non-high-risk acute promyelocytic leukemia (APL). However, the efficacy of ATRA-ATO compared to ATRA-ATO plus CHT in high-risk APL remains unknown. Here we performed a randomized multi-center non-inferiority phase III study to compare the efficacy of ATRA-ATO and ATRA-ATO plus CHT in newly diagnosed all-risk APL to address this question. Patients were assigned to receive ATRA-ATO for induction, consolidation, and maintenance or ATRA-ATO plus CHT for induction followed by three cycles of consolidation therapy, and maintenance therapy with ATRA-ATO. In the non-CHT group, hydroxyurea was used to control leukocytosis. A total of 128 patients were treated. The complete remission rate was 97% in both groups. The 2-year disease-free, event-free survival rates in the non-CHT group and CHT group in all-risk patients were 98% vs 97%, and 95% vs 92%, respectively (P = 0.62 and P = 0.39, respectively). And they were 94% vs 87%, and 85% vs 78% in the high-risk patients (P = 0.52 and P = 0.44, respectively). This study demonstrated that ATRA-ATO had the same efficacy as the ATRA-ATO plus CHT in the treatment of patients with all-risk APL.

How retinoic acid and arsenic transformed acute promyelocytic leukemia therapy.

Acute promyelocytic leukemia (APL) is associated with severe coagulopathy leading to rapid morbidity and mortality if left untreated. The definitive diagnosis of APL is made by identifying a balanced reciprocal translocation between chromosomes 15 and 17. This t(15;17) results in a fusion transcript of promyelocytic leukemia (PML) and retinoic acid receptor alpha (RARA) genes and the expression of a functional PML/RARA protein. Detection of a fused PML/RARA genomic DNA sequence using fluorescence in situ hybridization (FISH) or by detection of the PML/RARA fusion transcript via reverse transcriptase polymerase chain reaction (RT-PCR) has revolutionized the diagnosis and monitoring of APL. Once confirmed, APL is cured in over 90% of cases, making it the most curable subtype of acute leukemia today. Patients with low-risk APL are successfully treated using a chemotherapy-free combination of all-trans retinoic acid and arsenic trioxide (ATO). In this review, we explore the work that has gone into the modern-day diagnosis and highly successful treatment of this once devastating leukemia.

Tetra-arsenic tetra-sulfide enhances NK-92MI mediated cellular immunotherapy in all-trans retinoic acid-resistant acute promyelocytic leukemia.

Acute promyelocytic leukemia (APL) is liable to induce disseminated intravascular coagulation and has a high early mortality. Although the combination of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) has significantly improved the complete remission rate, there are still some patients developed drug resistance. Growing evidence suggests that natural killer (NK) cell-mediated immunotherapy as a new treatment can help slow the progression of hematological malignancies. Previous studies also indicated that some tumors exhibited excellent responsiveness to NK cells in vitro. However, many clinical trial results showed that the anti-tumor effect of NK cells infusion alone was not ideal, which may be related to the inactivation of infiltrating NK cells caused by strong immunosuppression in tumor microenvironment, but the specific mechanism remains to be further explored. In the present study, we demonstrated that low doses of tetra-arsenic tetra-sulfide (As4S4) not only enhanced the in vitro killing of NK-92MI against ATRA-resistant APL cells, but also strengthened the growth inhibition of xenografted tumors in APL mouse model. Mechanistically, As4S4 altered the expression of natural killer group 2 member D ligands (NKG2DLs) and cytokines in APL cells, and PD-1 in NK-92MI cells. In addition, database retrieval results further revealed the relationship between the differentially regulated molecules of As4S4 and immune infiltration and its impact on prognosis. In conclusion, our findings confirmed the potential of As4S4 as an adjuvant for NK-92MI in the treatment of ATRA-resistant APL.

ATRA works synergistically with the γ-secretase inhibitor crenigacestat to augment BCMA on multiple myeloma and the efficacy of BCMA-CAR T-cells.

B-cell maturation antigen (BCMA) is the lead antigen for CAR T-cell therapy in multiple myeloma (MM). A challenge is inter- and intra-patient heterogeneity in BCMA expression on MM cells and BCMA downmodulation under therapeutic pressure. Accordingly, there is a desire to augment and sustain BCMA expression on MM cells in patients that receive BCMA-CAR T-cell therapy. We used all-trans retinoic acid (ATRA) to augment BCMA expression on MM cells and to increase the efficacy of BCMA-CAR T-cells in pre-clinical models. We show that ATRA treatment leads to an increase in BCMA transcripts by quantitative PCR and an increase in BCMA protein expression by flow cytometry in MM cell lines and primary MM cells. Analyses with super-resolution microscopy confirmed increased BCMA protein expression and revealed an even distribution of non-clustered BCMA molecules on the MM cell membrane after ATRA treatment. The enhanced BCMA expression on MM cells after ATRA treatment led to enhanced cytolysis, cytokine secretion and proliferation of BCMA-CAR T-cells in vitro, and increased efficacy of BCMA-CAR T-cell therapy in a murine xenograft model of MM in vivo (NSG/MM1.S). Combination treatment of MM cells with ATRA and the γ-secretase inhibitor crenigacestat further enhanced BCMA expression and the efficacy of BCMA-CAR T-cell therapy in vitro and in vivo. Taken together, the data show that ATRA treatment leads to enhanced BCMA expression on MM cells and consecutively, enhanced reactivity of BCMA-CAR T-cells. The data support the clinical evaluation of ATRA in combination with BCMA-CAR T-cell therapy and potentially, other BCMA-directed immunotherapies.

All-trans retinoic acid works synergistically with the γ-secretase inhibitor crenigacestat to augment BCMA on multiple myeloma and the efficacy of BCMA-CAR T cells.

B-cell maturation antigen (BCMA) is the lead antigen for chimeric antigen receptor (CAR) T-cell therapy in multiple myeloma (MM). A challenge is inter- and intra-patient heterogeneity in BCMA expression on MM cells and BCMA downmodulation under therapeutic pressure. Accordingly, there is a desire to augment and sustain BCMA expression on MM cells in patients that receive BCMA-CAR T-cell therapy. We used all-trans retinoic acid (ATRA) to augment BCMA expression on MM cells and to increase the efficacy of BCMA-CAR T cells in pre-clinical models. We show that ATRA treatment leads to an increase in BCMA transcripts by quantitative reverse transcription polymerase chain reaction and an increase in BCMA protein expression by flow cytometry in MM cell lines and primary MM cells. Analyses with super-resolution microscopy confirmed increased BCMA protein expression and revealed an even distribution of non-clustered BCMA molecules on the MM cell membrane after ATRA treatment. The enhanced BCMA expression on MM cells after ATRA treatment led to enhanced cytolysis, cytokine secretion and proliferation of BCMA-CAR T cells in vitro, and increased efficacy of BCMA-CAR T-cell therapy in a murine xenograft model of MM in vivo (NSG/MM.1S). Combination treatment of MM cells with ATRA and the γ- secretase inhibitor crenigacestat further enhanced BCMA expression and the efficacy of BCMA-CAR T-cell therapy in vitro and in vivo. Taken together, the data show that ATRA treatment leads to enhanced BCMA expression on MM cells and consecutively, enhanced reactivity of BCMA-CAR T cells. The data support the clinical evaluation of ATRA in combination with BCMA-CAR T-cell therapy and potentially, other BCMA-directed immunotherapies.

Acute Myeloid Leukemia - Update 2022

The suspicion of acute myeloid leukemia (AML) is a haematological emergency that requires a rapid diagnostic workup. Symptoms are usually caused by cytopenias of all blood cell lines. The differentiation of acute promyelocytic leukemia (APL) is important because of the early death rate caused by thrombembolic and bleeding events. Rapid immunophenotypic and genetic characterization is necessary for risk stratification and therapy selection. For this purpose, a center with appropriate expertise should be contacted. Therapy has become more complex due to numerous new approvals. For certain patients, the established intensive induction therapy with cytarabine and anthracycline is now combined with targeted agents, like the antibody conjugate Gemtuzumab-Ozogamicin or the FLT3 inhibitor Midostaurin. Patients with secondary AML benefit from the liposomal chemotherapy combination CPX-351. Therapy with the hypomethylating agent Azacitidine and the BCL2-inhibitor Venetoclax (Aza/Ven) represents the standard for patients who are not fit for intensive therapy. Here, it is important to consider interactions with CYP3A4-effective drugs.In most cases, APL is treated "chemotherapy-free" with all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). In high-risk patients, the combination of chemotherapy and ATRA is still standard.Moreover, maintenance therapies were (re)established as an important therapeutic element of post-remission therapy. For example, Midostaurin is used in patients with FLT3 mutations, as is the multikinase inhibitor sorafenib after allogeneic stem cell transplantation. In addition, oral azacitidine is available for non-allogeneic transplant eligible patients in first complete remission. These new drugs have improved prognosis and resulted in a more individualized therapy mostly driven by genetic aberrations. This development will continue in the next years and will significantly improve treatment options, especially for older patients.

The immunomodulatory role of all-trans retinoic acid in tumor microenvironment.

Retinoids are essential nutrients for human beings. Among them, all-trans retinoic acid (ATRA), considered one of the most active metabolites, plays important roles in multiple biological processes. ATRA regulates the transcription of target genes by interacting with nuclear receptors bonded to retinoic acid response elements (RAREs). Besides its differentiation-inducing effect in the treatment of acute promyelocytic leukemia and some solid tumor types, its immunoregulatory role in tumor microenvironment (TME) has attracted considerable attention. ATRA not only substantially abrogates the immunosuppressive effect of tumor-infiltrating myeloid-derived suppressor cells but also activates the anti-tumor effect of CD8 + T cells. Notably, the combination of ATRA with other therapeutic approaches, including immune checkpoint inhibitors (ICIs), tumor vaccines, and chemotherapy, has been extensively investigated in a variety of tumor models and clinical trials. In this review, we summarize the current understanding of the role of ATRA in cancer immunology and immunotherapy, dissect the underlying mechanisms of ATRA-mediated activation or differentiation of different types of immune cells, and explore the potential clinical significance of ATRA-based cancer therapy.

Combination of midostaurin and ATRA exerts dose-dependent dual effects on acute myeloid leukemia cells with wild type FLT3

BackgroundMidostaurin combined with chemotherapy is currently used to treat newly diagnosed acute myeloid leukemia (AML) patients with FMS-like tyrosine kinase 3 (FLT3)-mutations. However, midostaurin acts as an antagonist to some chemotherapeutic agents in leukemia cell lines without FLT3 mutations. All-trans retinoic acid (ATRA) induces apoptosis when used in combination with midostaurin in FLT3-mutated AML cells. This combination has been shown to be safe in AML patients. However, the effect of this combination has not been investigated in AML without FLT3 mutations.MethodsCell proliferation was assessed by a cell counting assay. Cell death was evaluated by cell viability and Annexin-V assays. Cell differentiation was assessed by CD11b expression profiling and morphological analysis. To explore the underlying mechanisms, we studied the role of caspase3/7, Lyn, Fgr, Hck, RAF, MEK, ERK, AKT, PU.1, CCAAT/enhancer binding protein β (C/EBPβ) and C/EBPε by Western blot analysis and immunoprecipitation assays. Antitumor activity was also confirmed in mouse xenograft models established with AML cells.ResultsIn this study, 0.1 − 0.25 μM midostaurin (mido(L)) combined with ATRA induced differentiation while 0.25 − 0.5 μM midostaurin (mido(H)) combined with ATRA triggered apoptosis in some AML cell lines without FLT3-mutations. Midostaurin combined with ATRA (mido-ATRA) also exhibited antitumor activity in mouse xenograft models established with AML cells. Mechanistically, mido(H)-ATRA-induced apoptosis was dependent on caspase-3/7. Mido(L)-ATRA inhibited Akt activation which was associated with decreased activity of Lyn/Fgr/Hck, resulted in dephosphorylation of RAF S259, activated RAF/MEK/ERK, along with upregulating the protein levels of C/EBPβ, C/EBPε and PU.1. A MEK specific inhibitor was observed to suppress mido(L)-ATRA-induced increases in the protein levels of C/EBPs and PU.1 and mido(L)-ATRA-induced differentiation. Furthermore, inhibition of Akt activity promoted mido(L)-ATRA-induced downregulation of RAF S259 phosphorylation and mido(L)-ATRA-induced differentiation. Therefore, Lyn/Fgr/Hck-associated Akt inhibition activated RAF/MEK/ERK and controlled mido(L)-ATRA-induced differentiation by upregulation of C/EBPs and PU.1. Mido(L)-ATRA also promoted assembly of the signalosome, which may facilitate RAF activation.ConclusionsMidostaurin combined with ATRA exerts antitumor activity against AML with wild-type FLT3 mutations in vitro and in vivo. These findings may provide novel therapeutic strategies for some AML patients without FLT3 mutations and imply a new target of midostaurin.

Abstract 2124: ATRA mediated inhibition of myeloid-derived suppressor cells overcomes resistance to immune checkpoint inhibition in murine models of LKB1-deficient non-small cell lung cancer

Abstract Lung cancer remains the deadliest form of cancer, claiming the lives of 1.8 million worldwide in 2020. While treatment options have improved with the advent of immune checkpoint inhibitors (ICI), many patients do not respond to immunotherapy or develop resistance following initial response. A significant subset of patients harbor somatic mutations in both Kirsten rat sarcoma virus (KRAS) and Liver kinase 1 [LKB1, also known as serine/threonine kinase 11 (STK11)] genes. LKB1 loss has been identified as a driver of primary resistance to ICI therapy. Tumors from patients that possess these mutations are characterized by an increase in the population of myeloid derived suppressor cells (MDSCs). MDSCs are thought to play a critical role in promoting tumor progression by blocking the tumor killing function of cytotoxic T cells in the tumor microenvironment (TME). Our studies revealed all-trans retinoic acid (ATRA), a metabolite derived from vitamin A, sensitized murine models of non-small cell lung cancer (NSCLC) with LKB1 and KRAS co-mutations to PD-1 blockade. Combination therapy with anti-PD-1 and ATRA improved local and systemic T cell proliferation and generated systemic tumor-specific immunity. We observed that ATRA augmented anti-PD-1 efficacy in additional murine NSCLC models. We demonstrated that ATRA suppresses tumor growth through the inhibition of immunosuppressive MDSCs in the TME, and preliminary data indicates that ATRA increases intracellular reactive oxygen species (ROS) and IFN signaling in MDSC. Our findings implicate MDSCs as a potential mediator of immunosuppression in Lkb1-deficient NSCLC and provide a rationale for utilizing ATRA in combination with anti-PD-1 therapy in patients with Lkb1-deficient NSCLC refractory to ICIs. * B. Liu and S. M. Dubinett contributed equally to this work Citation Format: William P. Crosson, Rui Li, Ramin Salehi-Rad, Raymond J. Lim, Jensen W. Abascal, Bitta P. Kahangi, Edgar Perez Reyes, Camelia Dumitras, Zhe Jing, Kostyantyn Krysan, Linh M. Tran, Bin Liu, Steven M. Dubinett. ATRA mediated inhibition of myeloid-derived suppressor cells overcomes resistance to immune checkpoint inhibition in murine models of LKB1-deficient non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2124.

All-Trans-Retinoic Acid Combined With Valproic Acid Can Promote Differentiation in Myeloid Leukemia Cells by an Autophagy Dependent Mechanism.

Acute myeloid leukemia (AML) is an aggressive blood cancer with an overall survival of 30%. One form of AML, acute promyelocytic leukemia (APL) has become more than 90% curable with differentiation therapy, consisting of all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO). Application of differentiation therapy to other AML subtypes would be a major treatment advance. Recent studies have indicated that autophagy plays a key role in the differentiation of ATRA-responsive APL cells. In this study, we have investigated whether differentiation could be enhanced in ATRA resistant cells by promoting autophagy induction with valproic acid (VPA). ATRA sensitive (NB4) and resistant leukemia cells (NB4R and THP-1) were co-treated with ATRA and valproic acid, followed by assessment of autophagy and differentiation. The combination of VPA and ATRA induced autophagic flux and promoted differentiation in ATRA-sensitive and -resistant cell lines. shRNA knockdown of ATG7 and TFEB autophagy regulators impaired both autophagy and differentiation, demonstrating the importance of autophagy in the combination treatment. These data suggest that ATRA combined with valproic acid can promote differentiation in myeloid leukemia cells by mechanism involving autophagy.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

De-Escalating Therapy in Pediatric Acute Promyelocytic Leukemia

High cure rates are achieved in adults with acute promyelocytic leukemia (APML) using combined all-trans retinoic acid (ATRA) and arsenic trioxide,

Combination of Decitabine and ATRA in Newly Diagnosed Myelodysplastic Syndromes Subtype EB-Interim Analysis of a Multicenter, Randomized, Open-Label Trial

Background: HMAs are mainstay treatment of higher-risk myelodysplastic syndromes (MDS). However, clinical outcomes of patients treated with decitabine (DEC) monotherapy were far from satisfactory with an overall response rate (ORR) of 33%-55.4% and an overall survival (OS) of 17.7-22 months. Some clinical researches reported that the addition of all-trans retinoic acid (ATRA) to DEC increased response rate and prolonged survival of MDS and elderly acute myeloid leukemia (AML) patients. Our data showed ATRA enhanced the cytotoxic effect of DEC on MDS via activating RARα-Nrf2 complex (2021 EHA abstract EP891). These findings suggested that addition of ATRA to DEC in treatment-naive patients may improve response rate based on the synergetic function. We therefore conducted a study of combination of DEC and ATRA in MDS subtype excessive blasts (EB) patients.Methods: In this randomized, multicenter, open-label trial, patients with newly diagnosed MDS subtype EB based on the 2016 WHO classification from 7 different tertiary medical centers in China were included. Patients were randomized 1:1 to receive either oral ATRA (25mg/m 2/day on days 1-28) plus DEC (20 mg/m 2 daily on days 1-5) or DEC monotherapy（Figure 1）. The primary endpoint was overall response rate ORR, defined as complete remission (CR), partial remission (PR), marrow complete remission (mCR), or hematological improvement (HI). Key secondary endpoints were mCR, HI, overall survival (OS), and progress free survival (PFS). Response was assessed after completion of four cycles of treatment. For patients who bridged to allo-HSCT later on and did not complete four cycles of treatments, response was defined as best response ever observed before receiving allo-HSCT. Here, we report results of the interim analysis.Results: Between May 2018 and July 2021, 165 patients were randomly allocated into either DEC plus ATRA (n=82) or DEC monotherapy (n=83). 63.6% of patients were male and 36.4% were female, with a median age of 62 years (range, 19 to 81 years). 38.8% of patients had EB1 and 61.2% had EB2. As of July 31, 2021, 126 patients were available for the assessment of treatment results.After a median follow up of 9.6 months, median number of courses on treatment was 4 courses (range, 1-14), 61 in DEC plus ATRA arm and 65 in DEC arm . OR was achieved in 85.2% of DEC plus ATRA patients compared to 56.9% in DEC monotherapy (p<0.001). mCR rate was 73.8% in patients treated with DEC plus ATRA and 53.8% in those with DEC monotherapy (p=0.02). HI rate was 63.9% and 44.6% in patients with DEC plus ATRA and DEC monotherapy, respectively (p=0.03). The median OS and PFS were 18.8 months and 13.5 months for DEC plus ATRA arms, 19.2 months and 13.0 months for in DEC arm, respectively.72.7% patients developed at least one adverse event (AE) during the trial, 73.3% in the DEC plus ATRA arm and 72.0% in DEC arm, respectively. Grade 3/4 Hematological toxicity occurred in 73.68 % of DEC plus ATRA arm and 76.92 % of DEC arm. Hyperlipidemia occurred in 31 patients in DEC plus ATRA arm (3.2% grade 3/4), and 18 (no grade 3/4) in DEC arm (p<0.001). Incidence of headache was higher in DEC plus ATRA arm (14.7% vs 4.0% in DEC arm, respectively, p<0.001). No other statistically significant differences were observed in the incidence of treatment-related AEs between the two groups. No early death occurred.Conclusion: Combination of DEC and ATRA achieved an OR rate of 85.2% in MDS subtype EB. Enrollment is ongoing to assess its efficacy and safety in treating EB. This therapy may be a new treatment option for EB subjects. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Real World Data of Concurrent Arsenic Trioxide and All-Trans Retinoic Acid with Minimal Use of Anthracycline in the Treatment of Acute Promyelocytic Leukemia

▪In the setting of clinical trials, high cure rates have been reported for acute promyelocytic leukemia (APL) with the chemotherapy-free combination of arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) for low-intermediate risk disease, and with the addition of gemtuzumab ozogamicin or minimal anthracycline for high-risk disease. Despite clear in-vitro synergy between ATO and ATRA, most clinical trial protocols in APL have not used these drugs concurrently beyond induction. There is limited real world data on the use of chemotherapy-free combination of ATO and ATRA with minimal anthracycline use in the treatment of APL, especially in the high risk group. We did a retrospective analysis of the clinical outcomes of patients with newly diagnosed APL treated at our center from January 2015 to May 2020 using concurrent ATO, ATRA and minimal anthracycline in a risk stratified manner. The data was frozen and analyzed as on 1st June 2021. During the study period, 167 patients were diagnosed to have APL at our hospital. Of these, we excluded 5 patients who had presented with relapsed disease and 28 patients who were treated with single agent ATO. The remaining 134 patients were treated with a uniform protocol as summarized in Figure 1a. Figure 1b shows the KM plot for EFS (2 year: 90.8±2.5%) for these 134 patients. For analysis of regimen safety and efficacy, we excluded patients who wished to pursue treatment elsewhere within the first 1 week of treatment (n=7), and patients who had severe infections or life-threatening bleeding at presentation or before therapy initiation and subsequently died (n=4). Thus, a total of 123 patients with newly diagnosed APL were included for further analysis. The median age was 35 years (IQR: 24 to 45 years). Forty-six (37.4%) were females. The median duration of symptoms prior to admission was 14 days (IQR: 7 to 28 days). Sixty-one (49.6%) had high risk APL while the remaining 62 (50.4%) had low-intermediate risk APL. During induction, 28 (22.7%) patients had major bleeding while 5 (4%) patients developed major thrombosis. Sixty-seven (55%) patients had at least one documented infection during induction therapy. The median number of packed red cell concentrates, fresh frozen plasma, platelet rich concentrates and cryoprecipitates transfused during induction therapy was 5 (IQR: 3 to 6.5), 10 (IQR: 3 to 30), 40 (IQR: 23 to 55) and 6 (IQR: 0 to 18) respectively. Nineteen (15.4%) patients developed differentiation syndrome; all were treated with steroids, 8 required transient cessation of treatment and 6 required intensive care. Eight (6.5%) patients died during induction. During induction, grade 3 hepatotoxicity was noted in 8 (6.5%) patients, 10 (8.1%) patients had ATRA related headache or benign intracranial hypertension of which 5 required transient cessation of ATRA, while 11 (8.9%) patients had transient QTc prolongation of which 6 required transient cessation of ATO. Seventeen (13.8%) patients developed symptomatic sensory neuropathy requiring treatment. None required permanent discontinuation of therapy. At a median follow up of 854 days, there were 2 (1.6%) hematologic relapses and no deaths beyond induction therapy. The 2-year OS and EFS for the cohort (n=123) are 93.4% ± 2.3% and 91.6% ± 2.6% respectively (Figure 1c). Two (1.6%) patients have developed second malignancies. In a real world setting, concurrently administered ATO and ATRA with minimal anthracycline use results in excellent long term survival, even in the high risk group. Early deaths due to delayed presentation with infections and life threatening bleeding remain an unmet need for future research along with the need for strategies to reduce treatment-related toxicities. [Display omitted] DisclosuresMathews: Christian Medical College: Patents & Royalties: US 2020/0345770 A1 - Pub.Date Nov.5, 2020; AML: Other: Co-Inventor.

Genetic Ablation of Nuclear Receptor Interacting Protein 1 (NRIP1) Sensitizes Acute Myeloid Leukemia Cells to Retinoic Acids

The success of differentiation therapy is limited to acute promyelocytic leukemia (APL), and approaches to overcome the differentiation block in non-M3 AML have been unsuccessful. Nuclear hormone receptors (NHR) belong to ligand-inducible transcription factors that govern many cellular functions like differentiation, metabolism, and development. Retinoic Acid Receptor Alpha (RXRA) is a class of NHR that, when activated by all-trans retinoic acid (ATRA), successfully alleviates differentiation block in APL.To identify the NHRs/cofactors that could mediate or prevent differentiation in AML, we examined the differentially expressed NHRs and cofactors between ATRA sensitive (ATs) (NB4 and HL60) vs. ATRA resistant (ATr) AML cell lines (KG1a, Hel, K562, MV4-11, and OCI-AML3). Nuclear Receptor Interacting Protein 1 (NRIP1), a corepressor known to prevent transactivation of ligand-activated NHRs preferentially, was one of the top upregulated targets in the ATr cell lines (3.5 fold increase in RNA expression, figure 1a ). Immunoblot analysis also showed a significant increase in NRIP1 protein expression in the ATr than ATs cell lines (Figure 1b). Further, probing for NRIP1 expression in the publicly available TCGA and MILE AML study cohorts showed decreased NRIP1 expression in the APL cohort compared to other AML subtypes. Methylation profile from CCLE database of the NRIP1 promoter in AML cell lines showed ATs cell lines to be highly methylated compared to the ATr cell lines, suggesting the involvement of NRIP1 in mediating differentiation block in non-M3 AML (Figure 1c). To further dissect the role of NRIP1 in mediating this differentiation block, we carried out experiments in the AML cell line KG1a (having primitive blast features, high expression of NRIP1, and unresponsive to ATRA). Using CRISPR-cas9, we developed an NRIP1 knock-out (KO) cell line (Figure 1d). NRIP1 KO cell line showed a significant reduction in proliferation rate (Doubling time 26.2 vs. 36.5Hrs p<0.05). Further, cell cycle analysis revealed that NRIP1 KO leads to increased accumulation of cells in the G0 phase than in the S-phase (Figure 1e & f). We next assessed the sensitivity of the NRIP1 WT/KO cells to retinoic acids ATRA and bexarotene. Cells were treated with 1µM ATRA / bexarotene or in combination for 72 hours and evaluated for differentiation using CD11b marker by flow cytometry. NRIP1 KO alone leads to a marginal increase in basal CD11b expression compared to the WT cells (Mean CD11b expression 2.03% Vs 0.91%). ATRA treatment further increased the CD11b expression to 3.8% in KO cells compared to 1.6% in the WT cells. A similar increase in CD11b expression was observed in bexarotene-treated cells (3.7% Vs 1.24%). Combination of ATRA with bexarotene showed a 3-fold increase in CD11b expression in the KO cells compared to the WT (23.9% Vs 7.2%, Figure 1g). NRIP1 KO diminishes its repressive action on ligand-activated RARA (ATRA activated) and RXRA (Bexarotene-activated), thereby allowing synergistic differentiation induction by retinoic acids in AML cells.This study suggests a potential mechanism of differentiation inhibition mediated by corepressor NRIP1 in AML cells unresponsive to retinoic acids. Further in-depth analyses of molecular pathways governed by NRIP1 during ligand activation of NHRs are warranted to design differentiation therapies for AML. [Display omitted] DisclosuresMathews: Christian Medical College: Patents & Royalties: US 2020/0345770 A1 - Pub.Date Nov.5, 2020; AML: Other: Co-Inventor.