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 5

JARID1C loss deregulates expression of heterochromatic ncRNAs, triggering genomic instability.

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JARID1C loss deregulates expression of heterochromatic ncRNAs, triggerin...
(A) Western blot analysis and qPCR expression of the indicated ncRNAs in NIH-3T3 cells knocked down with CTRsh or J1CshA. Results are expressed relative to GAPDH as the mean ± SEM of 3 independent experiments. **P < 0.01, Student’s t test. (B) Total RNA from CTRsh, J1CshA, or J1CshB NIH-3T3 cells was collected and ncRNAs expression analyzed by qPCR. Results are expressed relative to GAPDH as the mean ± SEM of 1 of 3 experimental replicates. (C) Rescue experiments were performed as described in the Supplemental Methods. Results are expressed relative to GAPDH. Bars depict 1 representative experiment of 5 independently performed experiments. *P < 0.05 and **P < 0.01, Student’s t test. (D) Left: Representative immunofluorescence images of early-passage (P2) MEFs transduced with CTRsh or J1CshA-specific lentiviruses and analyzed for DAPI and α-tubulin (P5/P6). Right: Bars represent aberrant nuclei (see Supplemental Methods) in control and J1C-silenced MEFs, as quantified in 3 independent experiments (approximately 150 cells per condition for each experiment). Data are expressed as the mean ± SEM. *P < 0.05, Fisher exact test; n = 3 experimental replicates. (E) Expression of minor and major satellite repeats in MEFs knocked down with CTRsh or J1CshA and subsequently transfected with a control sequence (Mock LNAs) or a mixture of LNAs targeting both minor and major transcripts (Target LNAs). Bars depict the mean ± SEM of 3 independent experiments. *P < 0.05, Student’s t test. (F) Stacked bar chart shows percentages of normal and aberrant nuclei in CTRsh- and J1CshA-transduced MEFs (see Supplemental Methods). Bars represent the mean ± SEM of 3 independent experiments (n = 150 nuclei per condition per experiment). P < 0.001, χ2 test over the distribution of the mean.