Detection of molecular affecting sensitivity to local glucocorticoid therapy in oral lichen planus through transcriptome sequencing / 北京大学学报(医学版)

Objective:To detect key genes of local glucocorticoid therapy in oral lichen planus(OLP)through transcriptome sequencing.Methods:The study prospectively enrolled 28 symptomatic patients who visitied Department of Oral Mucosa,Peking University Hospital of Stomatology from November 2019 to March 2023.Topical inunction of 0.1 g/L of dexamethasone was applied for 1 min,3 times daily for 4 weeks.The patients'signs and pain symptoms were recorded and they were classified as effective group and ineffective group according to the treatment outcome.Their mucosa samples were collected before treatment.After isolating total RNA,transcriptome sequencing was performed.The gene expression data obtained by sequencing were analyzed differently using the DESeq2 package in R software,and the Kyoto encyclopedia of genes and genomes(KEGG)pathway enrichment analysis was performed on the basis of the hypergeometric distribution algorithm to describe the biological function of differentially expressed genes(DEGs),accordingly detecting sensitivity related molecular affecting therapeutic effect of dexamethasone.Results:After 4 weeks treatment by topical dexamethasone,13 cases of the 28 OLP pa-tients responding well with the sign score reducing from 7.0(4.5,9.0)to 5.0(3.0,6.3),pain score decreasing from 5.0(2.0,5.5)to 2.0(0.0,3.5),oral health impact profile lessening from 5.0(3.5,9.0)to 1.0(0.0,5.0)significantly(P＜0.01)were classified as effective group and 15 cases with poor response to the drug were sorted as ineffective group.There were no significant differences of demographic and baseline levels of clinical features,especially disease severity between these two groups.A total of 499 DEGs including 274 upregulated and 225 downregulated genes were identified between ef-fective group and ineffective group.KEGG enrichment analysis showed that upregulated genes in effective group compared with ineffective group including CLDN8,CTNNA3,MYL2 and MYLPF were associated with leukocyte transendothelial migration,while downregulated genes were significantly enriched in tumor necrosis factor(TNF),interleukin-17(IL-17),nuclear factor kappa B(NF-κB)signaling pathways,and cortisol synthesis and secretory.Conclusion:High expressions of CLDN8,CTNNA3,MYL2 and MYLPF genes in patients with oral lichen planus have a good clinical response to topical dexamethasone,while patients with high expression genes of inflammation pathway such as TNF,IL-17,NF-κB and corti-sol synthesis and secretion received poor effect.

Multiple Roles of BRIT1/MCPH1 in DNA Damage Response, DNA Repair, and Cancer Suppression

Mammalian cells are frequently at risk of DNA damage from both endogenous and exogenous sources. Accordingly, cells have evolved the DNA damage response (DDR) pathways to monitor and assure the integrity of their genome. In cells, the intact and effective DDR is essential for the maintenance of genomic stability and it acts as a critical barrier to suppress the development of cancer in humans. Two central kinases for the DDR pathway are ATM and ATR, which can phosphorylate and activate many downstream proteins for cell cycle arrest, DNA repair, or apoptosis if the damages are irreparable. In the last several years, we and others have made significant progress to this field by identifying BRIT1 (also known as MCPH1) as a novel key regulator in the DDR pathway. BRIT1 protein contains 3 breast cancer carboxyl terminal (BRCT) domains which are conserved in BRCA1, MDC1, 53BP1, and other important molecules involved in DNA damage signaling, DNA repair, and tumor suppression. Our in vitro studies revealed BRIT1 to be a chromatin-binding protein required for recruitment of many important DDR proteins (ATM, MDC1, NBS1, RAD51, BRCA2) to the DNA damage sites. We recently also generated the BRIT1 knockout mice and demonstrated its essential roles in homologous recombination DNA repair and in maintaining genomic stability in vivo. In humans, BRIT1 is located on chromosome 8p23.1, where loss of hetero-zigosity is very common in many types of cancer. In this review, we will summarize the novel roles of BRIT1 in DDR, describe the relationship of BRIT1 deficiency with cancer development, and also discuss the use of synthetic lethality approach to target cancers with HR defects due to BRIT1 deficiency.

Multiple Roles of BRIT1/MCPH1 in DNA Damage Response, DNA Repair, and Cancer Suppression

Mammalian cells are frequently at risk of DNA damage from both endogenous and exogenous sources. Accordingly, cells have evolved the DNA damage response (DDR) pathways to monitor and assure the integrity of their genome. In cells, the intact and effective DDR is essential for the maintenance of genomic stability and it acts as a critical barrier to suppress the development of cancer in humans. Two central kinases for the DDR pathway are ATM and ATR, which can phosphorylate and activate many downstream proteins for cell cycle arrest, DNA repair, or apoptosis if the damages are irreparable. In the last several years, we and others have made significant progress to this field by identifying BRIT1 (also known as MCPH1) as a novel key regulator in the DDR pathway. BRIT1 protein contains 3 breast cancer carboxyl terminal (BRCT) domains which are conserved in BRCA1, MDC1, 53BP1, and other important molecules involved in DNA damage signaling, DNA repair, and tumor suppression. Our in vitro studies revealed BRIT1 to be a chromatin-binding protein required for recruitment of many important DDR proteins (ATM, MDC1, NBS1, RAD51, BRCA2) to the DNA damage sites. We recently also generated the BRIT1 knockout mice and demonstrated its essential roles in homologous recombination DNA repair and in maintaining genomic stability in vivo. In humans, BRIT1 is located on chromosome 8p23.1, where loss of hetero-zigosity is very common in many types of cancer. In this review, we will summarize the novel roles of BRIT1 in DDR, describe the relationship of BRIT1 deficiency with cancer development, and also discuss the use of synthetic lethality approach to target cancers with HR defects due to BRIT1 deficiency.