A case of life-threatening retinoic acid syndrome and review of literature

Multi-species transcriptome meta-analysis of the response to retinoic acid in vertebrates and comparative analysis of the effects of retinol and retinoic acid on gene expression in LMH cells

Background

Retinol (RO) and its active metabolite retinoic acid (RA) are major regulators of gene expression in vertebrates and influence various processes like organ development, cell differentiation, and immune response. To characterize a general transcriptomic response to RA-exposure in vertebrates, independent of species- and tissue-specific effects, four publicly available RNA-Seq datasets from Homo sapiens, Mus musculus, and Xenopus laevis were analyzed. To increase species and cell-type diversity we generated RNA-seq data with chicken hepatocellular carcinoma (LMH) cells. Additionally, we compared the response of LMH cells to RA and RO at different time points.

Results

By conducting a transcriptome meta-analysis, we identified three retinoic acid response core clusters (RARCCs) consisting of 27 interacting proteins, seven of which have not been associated with retinoids yet. Comparison of the transcriptional response of LMH cells to RO and RA exposure at different time points led to the identification of non-coding RNAs (ncRNAs) that are only differentially expressed (DE) during the early response.

Conclusions

We propose that these RARCCs stand on top of a common regulatory RA hierarchy among vertebrates. Based on the protein sets included in these clusters we were able to identify an RA-response cluster, a control center type cluster, and a cluster that directs cell proliferation. Concerning the comparison of the cellular response to RA and RO we conclude that ncRNAs play an underestimated role in retinoid-mediated gene regulation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07451-2.

Heterogeneous Differentiation of Highly Proliferative Embryonal Carcinoma PCC4 Cells Induced by Curcumin: An In Vitro Study

Curcumin, the yellow pigment derived from turmeric rhizomes, exhibits antioxidant, anti-inflammatory, antimicrobial, and anticancer properties. We have previously reported in a study that curcumin could induce differentiation in embryonal carcinoma cell (EC). EC cells are the primary constituents of teratocarcinoma tumors, and hence differentiating them to a non-proliferative cell type may be useful in anticancer therapies. Here, we conducted a detailed study using various molecular approaches to characterize this differentiation at the cellular and molecular levels. The cells were treated with 20 µM curcumin, which was the optimal concentration to produce the highest amount of differentiated cells. Changes in protein and RNA expression, membrane dynamics, and migration of these cells after treatment with curcumin were then studied in a time-dependent manner. The differentiated cells were morphologically distinct from the precursor cells, and gene expression profiles were altered in curcumin-treated cells. Curcumin promoted cell motility and cell adhesion. Curcumin also induced changes in membrane fluidity and the lateral mobility of lipids in the plasma membrane. The findings of this study suggest that curcumin might have therapeutic potential in differentiation therapy for the treatment of teratocarcinomas or germ cell tumors (GCTs) such as testicular and ovarian GCTs.

Retinoid Chemoprevention: Who Can Benefit?

Acute promyelocytic leukemia (APL) is a treatment success story. From a highly deadly disease it was turned into a highly curable disease by the introduction of differentiation-induction therapy with all-trans retinoic acid (ATRA) in the 1990's. During the last quarter of century, ATRA and other retinoids were used for the treatment and prevention of other cancers and even other diseases. The results were less spectacular, but nevertheless important. Progress has been made toward understanding the mechanism of action of retinoids in different physiological and pathological contexts. For some diseases, specific genetic backgrounds were found to confer responsiveness to retinoid therapy. Therapies that include retinoids and other modalities are very diverse and used both for combined targeting of multiple pathways and for diminishing toxicity.