Histone demethylase JARID1C inactivation triggers genomic instability in sporadic renal cancer
Beatrice Rondinelli, … , Davide Cittaro, Giovanni Tonon
Beatrice Rondinelli, … , Davide Cittaro, Giovanni Tonon
Published November 9, 2015
Citation Information: J Clin Invest. 2015;125(12):4625-4637. https://doi.org/10.1172/JCI81040.
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Research Article Genetics Oncology

Histone demethylase JARID1C inactivation triggers genomic instability in sporadic renal cancer

Abstract

Mutations in genes encoding chromatin-remodeling proteins are often identified in a variety of cancers. For example, the histone demethylase JARID1C is frequently inactivated in patients with clear cell renal cell carcinoma (ccRCC); however, it is largely unknown how JARID1C dysfunction promotes cancer. Here, we determined that JARID1C binds broadly to chromatin domains characterized by the trimethylation of lysine 9 (H3K9me3), which is a histone mark enriched in heterochromatin. Moreover, we found that JARID1C localizes on heterochromatin, is required for heterochromatin replication, and forms a complex with established players of heterochromatin assembly, including SUV39H1 and HP1α, as well as with proteins not previously associated with heterochromatin assembly, such as the cullin 4 (CUL4) complex adaptor protein DDB1. Transcription on heterochromatin is tightly suppressed to safeguard the genome, and in ccRCC cells, JARID1C inactivation led to the unrestrained expression of heterochromatic noncoding RNAs (ncRNAs) that in turn triggered genomic instability. Moreover, ccRCC patients harboring JARID1C mutations exhibited aberrant ncRNA expression and increased genomic rearrangements compared with ccRCC patients with tumors endowed with other genetic lesions. Together, these data suggest that inactivation of JARID1C in renal cancer leads to heterochromatin disruption, genomic rearrangement, and aggressive ccRCCs. Moreover, our results shed light on a mechanism that underlies genomic instability in sporadic cancers.

Authors

Beatrice Rondinelli, Dalia Rosano, Elena Antonini, Michela Frenquelli, Laura Montanini, DaChuan Huang, Simona Segalla, Kosuke Yoshihara, Samir B. Amin, Dejan Lazarevic, Bin Tean The, Roel G.W. Verhaak, P. Andrew Futreal, Luciano Di Croce, Lynda Chin, Davide Cittaro, Giovanni Tonon

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Figure 4

JARID1C, together with DDB1, belongs to a heterochromatin-remodeling complex and acts upstream of HP1α and SUV39H1.

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JARID1C, together with DDB1, belongs to a heterochromatin-remodeling com...
Co-IP of JARID1C (J1C) with (A) HP1α, (B) SUV39H1, and (C) DDB1 in Caki-1 renal cancer cells. (A) IP for JARID1C and Western blotting for JARID1C and HP1α, (B) for JARID1C and a Myc Ab against SUV39H1, and C) for JARID1C and an HA Ab against DDB1, respectively. (D) Left: Total cell lysates of control (CTRsh) and downregulated (J1CshA) NIH-3T3 cells were analyzed by Western blotting for expression of JARID1C, HP1α, and β-actin. Middle: Representative confocal immunofluorescence images of NIH-3T3 cells stained with anti-HP1α–specific Ab and DAPI. Representative cells with (positive) or without (negative) heterochromatic HP1α dots are shown. Right: Graphs represent quantification (percentage of cells) of positive and negative CTRsh- and J1CshA-transfected cells from 3 independent experiments. Approximately 150 cells per condition were counted in each experiment. *P < 0.05, Fisher’s exact test. (E) Confocal immunofluorescence images of control and silenced NIH-3T3 cells transfected with Myc-tagged SUV39H1 and stained with anti-Myc–specific Ab and DAPI. Representative cells with heterochromatic Myc dots (positive) and without dots (negative) are shown. Graph represents quantification of CTRsh and J1CshA cells with heterochromatic Myc-SUV39H1 dots from 2 independent experiments. Approximately 100 cells per condition were counted in each experiment. *P < 0.05, Fisher’s exact test. (F) Chromatin of NIH-3T3 rescue experiment was immunoprecipitated with an anti-HP1α–specific Ab. Enrichment was analyzed by qPCR at major repeats using specific primers. Results are expressed as the percentage of input. Orange square represents ChIP performed with control IgGs. Error bars represent the SEM of 3 independent replicates. *P < 0.05, Student’s t test. IB, immunoblot; TI, total input.