Fudan University Shanghai Cancer Center and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China.
Cancer Institute, Shanghai Medical College, Fudan University, Shanghai 200032, China.
Theranostics. 2020 Apr 6;10(12):5242-5258. doi: 10.7150/thno.43744. eCollection 2020.
: Chromodomain Y-like 2 (CDYL2) is a member of the CDY gene family involved in spermatogenesis, but its role in human cancer has not been reported. Analyses of publicly available databases demonstrate that CDYL2 is abundantly expressed in breast tumors. However, whether CDYL2 is involved in breast cancer progression remains unknown. : Quantitative real-time PCR and immunoblotting assays were used to determine the expression levels of CDYL2 transcript variants in breast cancer cell lines and primary breast tumors. The effect of CDYL2 transcript variants on the malignant phenotypes of breast cancer cells was examined through and assays. Immunofluorescent staining, RNA-seq, ATAC-seq, and ChIP-qPCR were used to investigate the underlying mechanisms behind the aforementioned observations. : Here we show that CDYL2 generated four transcript variants, named CDYL2a-CDYL2d. CDYL2a and CDYL2b were the predominant variants expressed in breast cancer cell lines and breast tumors and exerted strikingly discrete functions in breast cancer growth and metastasis. CDYL2a was upregulated in the majority of the breast cancer cell lines and tumors, and promoted breast cancer cell proliferation, colony formation , and tumorigenesis in xenografts. In contrast, CDYL2b was mainly expressed in luminal- and HER2-positive types of breast cancer cell lines and tumors, and suppressed the migratory, invasive, and metastatic potential of breast cancer cells and . Mechanistically, CDYL2a partially localized to SC35-positive nuclear speckles and promoted alternative splicing of a subset of target genes, including FIP1L1, NKTR, and ADD3 by exon skipping. Elimination of full-length FIP1L1, NKTR, and ADD3 rescued the impaired cell proliferation through CDYL2a depletion. In contrast, CDYL2b localized to heterochromatin and transcriptionally repressed several metastasis-promoting genes, including HPSE, HLA-F, and SELL. Restoration of HPSE, HLA-F, or SELL expression in CDYL2b-overexpressing cells attenuated the ability of CDYL2b to suppress breast cancer cell migration and invasion. : Collectively, these findings establish an isoform-specific function of CDYL2 in breast cancer development and progression and highlight that pharmacological inhibition of the CDYL2a, but not the CDYL2b, isoform may be an effective strategy for breast cancer therapy.
CDYL2 是 CDY 基因家族的成员之一，参与精子发生，但它在人类癌症中的作用尚未报道。对公开数据库的分析表明，CDYL2 在乳腺癌中大量表达。然而，CDYL2 是否参与乳腺癌的进展尚不清楚。
我们使用定量实时 PCR 和免疫印迹分析来确定乳腺癌细胞系和原发性乳腺癌组织中 CDYL2 转录变体的表达水平。通过划痕和侵袭实验，研究了 CDYL2 转录变体对乳腺癌细胞恶性表型的影响。免疫荧光染色、RNA-seq、ATAC-seq 和 ChIP-qPCR 用于研究上述观察结果的潜在机制。
在这里，我们展示了 CDYL2 产生了四个转录变体，分别命名为 CDYL2a-CDYL2d。CDYL2a 和 CDYL2b 是在乳腺癌细胞系和乳腺癌组织中表达最丰富的变体，并且在乳腺癌的生长和转移中发挥了截然不同的作用。CDYL2a 在大多数乳腺癌细胞系和肿瘤中上调，并促进乳腺癌细胞增殖、集落形成和异种移植中的肿瘤发生。相比之下，CDYL2b 主要在腔型和 HER2 阳性的乳腺癌细胞系和肿瘤中表达，并抑制乳腺癌细胞的迁移、侵袭和转移潜力。
在机制上，CDYL2a 部分定位于 SC35 阳性核斑点，并通过外显子跳跃促进包括 FIP1L1、NKTR 和 ADD3 在内的一组靶基因的选择性剪接。通过 CDYL2a 耗竭消除全长 FIP1L1、NKTR 和 ADD3，可挽救因 CDYL2a 缺失而导致的增殖受损。相比之下，CDYL2b 定位于异染色质，并转录抑制包括 HPSE、HLA-F 和 SELL 在内的几个促进转移的基因。在 CDYL2b 过表达细胞中恢复 HPSE、HLA-F 或 SELL 的表达，可减弱 CDYL2b 抑制乳腺癌细胞迁移和侵袭的能力。
总之，这些发现确立了 CDYL2 在乳腺癌发生和发展中的异构体特异性功能，并强调了药理学抑制 CDYL2a（而不是 CDYL2b）异构体可能是一种有效的乳腺癌治疗策略。
