DNA methylation and Transcriptome Changes Associated with Cisplatin Resistance in Ovarian Cancer

Abstract

High-grade serous ovarian cancer is the most common ovarian cancer type. Although the combination of surgery and platinum-taxane chemotherapy provide an effective treatment, drug resistance frequently occurs leading to poor outcome. In order to clarify the molecular mechanisms of drug resistance, the DNA methylation and transcriptomic changes, associated with the development of drug resistance in high-grade serous ovarian cancer, were examined from patient derived malignant ascites cells. In parallel with large-scale transcriptome changes, cisplatin resistance was associated with loss of hypermethylation at several CpG sites primarily localized in the intergenic regions of the genome. The transcriptome and CpG methylome changes in response to cisplatin treatment of both sensitive and resistant cells were minimal, indicating the importance of post-translational mechanisms in regulating death or survival of the cells. The response of resistant cells to high concentrations of cisplatin revealed transcriptomic changes in potential key drivers of drug resistance, such as KLF4. Among the strongest changes was also induction of IL6 in resistant cells and the expression was further increased in response to cisplatin. Also, several other components of IL6 signaling were affected, further supporting previous observations on its importance in malignant transformation and development of drug resistance in ovarian cancer.High-grade serous ovarian cancer (HGSOC) is the most common ovarian cancer subtype and accounts for 80% of the deaths caused by the disease. The prognosis of HGSOC is poor as most diagnosis is at late stages of the disease when the 10-year survival rate is only in the order of 15%. The main strategy for treatment involves surgical removal of the tumor tissue and chemotherapy 1 . Platinium compounds, such as cisplatin, in combination with taxane are typically used in chemotherapy. However, recurrence of the cancer is frequent and most of the patients will eventually become refractory to the treatment 2 . In order to improve the prognosis of the patients with HGSOC, new biomarkers enabling early diagnosis of the disease as well as new therapeutic strategies overcoming the drug resistance are needed 1,3 . Detailed characterization of the molecular mechanisms leading to drug resistance is important for development of improved therapies.The molecular mechanisms leading to drug resistance can be heterogeneous and complex 4 . In addition to genetic factors, the development may involve epigenetic changes, which enable tumor cells, and possibly non-transformed cells in the microenvironment, to adapt and lose sensitivity to drug treatment. DNA methylation and transcriptional changes associated with drug resistance have been detected in several genomic sites in both cell lines and patient samples [5][6][7][8] . For example, methylation and transcriptional silencing of the MLH1 gene have been repeatedly associated with cisplatin resistance 8,9 . Although several candidate driver genes for cisplatin resistance have been ...

Vitamin D promotes the cisplatin sensitivity of oral squamous cell carcinoma by inhibiting LCN2-modulated NF-κB pathway activation through RPS3

“…Chemotherapy sensitivity may be due to changes in gene expression caused by epigenetic changes such as DNA methylation at the promoter after treatment 18 . Methylation at promoters has been reported to play an important role in regulating LCN2 expression 17 .…”

Resistance to cis- and carboplatin initiated by epigenetic changes in ovarian cancer patients

“…Resistance/sensitization Genes Cisplatin resistance OXCT1 [18] , GPCR [19] , TET1 [20] , MLH1 [21][22][23] , HOXA10, HOXA11 [21,24] , NAGA [25] , UCHL1 [26] , BCL2L1 [27] , FANCF [28][29][30] Cisplatin sensitization FANCF [31] , NAGA [25] , CCDC69 [32] , UCHL1 [26] Carboplatin Resistance TMEM88 [33] , DOK2 [34,35] , p57(Kip2) [36] , Plk2 [37] , HERV-K [38] , SFRP5 [39] , SLFN11 [40] , ASS1 [41] ASS1: argininosuccinate synthase 1; BCL2L1: BCL2 like 1; CCDC69: coiled-coil domain containing 69; DOK2: docking protein 2; FANCF: fanconi anemia complementation group F; GPCR: protein coupled receptor; HOXA: homeobox A cluster; HERV-K: for HERV-K: human endogenous retrovirus type K; MLH1: mutL homolog 1; NAGA: N-acetylgalactosaminidase; OXCT1: 3-oxoacid CoA-transferase 1; Plk2: polo like kinase 2; SFRP5: secreted frizzled-related protein 5; SLFN11: schlafen family member 11; TET1: tet methylcytosine dioxygenase 1; TMEM88: transmembrane protein 88; UCHL1: ubiquitin C-terminal hydrolase L1 β-catenin independent (non-canonical) pathways. Wnt proteins bind to receptors of the Frizzled and the low-density lipoprotein receptor-related protein families on the cell surface.…”

Methylation and ovarian cancer: Can DNA methylation be of diagnostic use? (Review)

“…A study from 2017 also suggests that hypomethylation can be induced by cisplatin treatment in resistant OC patients, however loss of methylation was primarily observed in intergenic regions (109). Other recent studies have suggested a correlation between hypomethylation of developmental genes and platinum resistance in OC patients.…”