ABSTRACT
Objective:To evaluate the inhibitory effect of a retinoid derivative ECPIRM on proliferation of a cutaneous T-cell lymphoma (CTCL) cell line HH, and to explore its potential mechanisms.Methods:Cultured HH cells were treated with ECPIRM at different concentrations of 0 (control group) , 5, 10 and 20 μmol/L separately for 72 hours, cell counting kit-8 (CCK8) assay was performed to evaluate the effect of ECPIRM on the proliferative activity of HH cells, and flow cytometry to investigate the effect of ECPIRM on apoptosis of HH cells. Some HH cells were treated with 10 μmol/L ECPIRM for 72 hours, transcriptome sequencing was performed to investigate gene expression changes triggered by ECPIRM in HH cells, and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis and gene ontology (GO) enrichment analysis were then performed to analyze differentially expressed genes in HH cells induced by ECPIRM. Reverse transcription-qPCR was subsequently conducted to verify changes in key gene expression in related pathways. Intergroup differences were analyzed by using one-way analysis of variance, and least significant difference (LSD) - t test was used for multiple comparisons. Results:CCK8 assay showed that the 50% inhibitory concentration (IC50) of ECPIRM on HH cells was 4.91 ± 2.48 μmol/L, the viability of HH cells significantly differed among the control group, and 5-, 10-and 20-μmol/L ECPIRM groups (100.00% ± 2.87%, 49.58% ± 4.53%, 48.36% ± 2.88%, 31.44% ± 2.46%, respectively, F=162.86, P < 0.001) , and was significantly lower in the 5-, 10-and 20-μmol/L ECPIRM groups than in the control group ( t=15.36, 15.73, 20.89, respectively, all P < 0.001) . Flow cytometry showed that there was a significant difference in the apoptosis rate among the 4 groups (11.51% ± 1.84%, 23.83% ± 5.72%, 36.19% ± 8.33%, 49.75% ± 4.10%, respectively, F=17.62, P < 0.001) , and the 10-and 20-μmol/L groups showed significantly increased apoptosis rates compared with the control group ( t=4.46, 6.92 respectively, both P < 0.01) . Transcriptomics analysis revealed that the inhibitory effect of ECPIRM on the cellular proliferative activity may be related to the metabolic regulation of steroids. As reverse transcription-qPCR revealed, the 10-μmol/L ECPIRM group showed significantly decreased mRNA expression of L-amino acid oxidase (IL4I1) , acetyl-coenzyme A acetyltransferase 2 (ACAT2) , 3-hydroxy-3-methylglutaryl-coenzyme A synthase 1 (HMGCS1) , mevalonate diphosphate decarboxylase (MVD) , 3-β-hydroxysteroid-8,7-isomerase (EBP) , very low-density lipoprotein receptor (VLDLR) , 3-hydroxy 3-methylglutaryl-CoA reductase (HMGCR) compared with the control group (all P < 0.05) . Conclusion:The retinoid derivative ECPIRM exerted marked anti-proliferative and apoptosis-inducing effects on HH cells, which may be related to the decreased expression of key genes involved in steroid metabolism.
ABSTRACT
Objective To estimate the effect of a tretinoin derivative ECPIRM on retinoic acid receptors (RARs),and to observe skin irritation responses to it in mice.Methods Cultured SCL-1 cells were divided into 2 groups to be treated with culture medium containing 10 μmol/L ECPIRM (ECPIRM group) or 10 μmol/L all-trans retinoic acid (ATRA) (ATRA group) for 24 hours,and those treated with drug-free culture medium served as the control group.Western blot analysis and real-time fluorescence-based quantitative PCR were performed to quantify the protein and mRNA expressions of RARs (RARα,RARβ,RARγ and RXRα) respectively.In addition,real-time fluorescence-based quantitative PCR was conducted to measure the mRNA expressions of two target genes of the activated RAR signaling pathway,i.e.,cytochrome P450 26A1 (CYP26A1) and tazarotene-induced gene 1 (TIG1).Eight BALB/c mice were equally divided into 2 groups to be topically treated with 0.075％ ECPIRM gel or 0.05％ ATRA cream at equal molar concentrations on the shaved skin once daily for 21 successive days.Skin irritation reactions were assessed in these mice.Results Compared with the control group,the ATRA group showed significantly increased protein and mRNA expressions of RARα,RARβ and RARγ (all P ＜ 0.05).The mRNA expressions of CYP26A1 and TIG1 genes in the ATRA group were 25.49 and 3.88 times that in the control group respectively (both P ＜ 0.01).However,there was no significant difference in the protein expressions of RARα,RARβ,RARγ and RXRα,or mRNA expressions of RARα,RARβ,RARγ CYP26A1 and TIG1 between the ECPIRM group and control group (all P ＞ 0.05).Obvious Skin irritation reactions such as erythema and desquamation were observed in BALB/c mice after 2-day topical treatment with ATRA cream,and their degree peaked after 5-day treatment.However,neither erythema nor desquamation was observed in BALB/c mice during 21-day treatment with 0.075％ ECPIRM gel.Conclusion Unlike ATRA,ECPIRM cannot activate the canonical RAR signaling pathway or cause skin irritation reactions.