Biology subjects

Nishio, K.

Publications and source records attributed to Nishio, K..

4 recordsLinked to original sources

bioRxiv2021

Frequent PIK3CA mutations in eutopic endometrium of patients with ovarian clear cell carcinoma

Recent studies have reported cancer-associated mutations in normal endometrium. Mutations in eutopic endometrium may lead to endometriosis and endometriosis-associated ovarian cancer. We investigated PIK3CA mutations (PIK3CAm) for three hotspots (E542K, E545K, H1047R) in eutopic endometrium in patients with ovarian cancer and endometriosis from formalin-fixed paraffin-embedded specimens by laser-capture microdissection and droplet digital PCR. The presence of PIK3CAm in eutopic endometrial glands with mutant allele frequency [≥]15% were as follows: ovarian clear cell carcinoma (OCCC) with PIK3CAm in tumors, 20/300 hotspots in 11/14 cases; OCCC without PIK3CAm, 42/78 hotspots in 11/12 cases; high-grade serous ovarian carcinoma, 8/45 hotspots in 3/5 cases; and endometriotic cysts, 5/63 hotspots in 5/6 cases. These rates were more frequent than in non-cancer non-endometriosis controls (7/309 hotspots in 5/17 cases). In OCCC without PIK3CAm, 7/12 (58%) cases showed multiple hotspot mutations in the same eutopic endometrial glands. In 3/54 (5.6%) cases, PIK3CAm was found in eutopic endometrial stroma. Multi-sampling of the OCCC tumors with PIK3CAm showed intratumor heterogeneity in three of eight cases. In two cases, PIK3CAm was detected in the stromal component of the tumor. Homogenous PIK3CAm in the epithelial component of the tumor matched the mutation in eutopic endometrial glands in only one case. Eutopic endometrial glands in ovarian cancer and endometriosis show high frequency of PIK3CAm that is not consistent with tumors, and multiple hotspot mutations are often found in the same glands. Our results suggest that most PIK3CAm in eutopic endometrial glands are passenger rather than driver mutations.

cancer biology↗

bioRxiv2019

Differential effects of Doxorubicin and Actinomycin D on the stability of RNA binding proteins, RBM10 and RBM5: Actinomycin D promotes the nuclear speckles targeting of RBM10 and RBM5 through the novel structural elements.

BackgroundRNA binding motif (RBM) proteins, RBM10v1, RBM10v2 and RBM5 share a high degree of the conserved domains. So far, the drug-sensitivities of the RBMs in tumor cells have not been fully examined.\n\nObjectiveThe expression profiles of RBM10 and RBM5 in several virus-transformed tumor cells, and the effect of the most established antitumor agents, actinomycin D and doxorubicin, were investigated.\n\nMethods and ResultsDoxorubicin and actinomycin D differentially reduced RBM10 and RBM5 protein, respectively in both of HeLa and COS-7 cells. RBM10 protein was highly sensitive to doxorubicin in HeLa, COS-7 and A549 cells. In silico analysis revealed the several sumoylation sites of RBM10 and its sumoylated form could be targeted for the activated ubiquitin proteasome system. Actinomycin D affected the nuclear speckles localization of RBM10 and RBM5 in COS-7 and A549 lung carcinoma cells. Addition of actinomycin D in the culture medium and following culture for 34 hours promoted the prominent nuclear speckles of RBM10v2-GFP and RBM5. Hence, we explored the subnuclear localization of the full length RBM10v2 (852aa) and the amino terminally truncated forms and the responsible structural elements. The amino terminally truncated RBM10v2 [#486-852, #642-852], RBM10v2 [#648-852], RBM10v2 [#681-759, #681-852], and RBM10v2 [#660-852] retained the targeting elements for the nuclear speckles, nucleoplasm, nucleoli and whole nuclei, respectively.\n\nConclusionRBM10 is highly sensitive to doxorubicin. Actinomycin D affects the structural elements of RBM10 and promotes the nuclear speckles targeting. The C-terminal regions: RBM10v2 [#642-647], [#642-659], and [#660-680] play critical roles in the targeting to the subnuclear compartments. SIM and sumoylation sits of RBM10 and PML4 are important for molecular interaction of RBM10 and PML.

cell biology↗

bioRxiv2019

RBM10 variants and RBM5 involve in alternative splicing of RBM10v1 pre-mRNA: RBM10v1 includes its own exon 4, but RBM10v2 and RBM5 skip it.

RNA binding motif (RBM) proteins, RBM10v1, RBM10v2 and RBM5 have quite similar molecular structures with a high degree of the conserved domains. Alternative splicing of RBM10 pre-mRNA produces the two mRNA variants, RBM10v1 (exon 4-included) and RBM10v2 (exon 4-skipped). RBM10v1 has a 77 amino acids-domain coded by its exon 4, but RBM10v2 lacks it. I explored the alternative splicing of the RBM10 pre-mRNA by the above three RBMs in COS-7, lung adenocarcinoma A549 and differentiated mouse cardiomyocytes H9c2 cells. Firstly, COS-7 and A549 cells express both RBM10v1 and RBM10v2 mRNA variants in contrast to H9c2 cells which express RBM10v2 variant alone. Transfection experiments of RBM10v1, RBM10v2 or RBM5 were performed to examine the alternative splicing of RBM10v1 pre-mRNA in COS-7, A549 and H9c2 cells. The result showed that RBM10v1 includes, by itself, its own exon 4 of the pre-mRNA in contrast to RBM10v2 and RBM5 which exclude the exon 4. The inclusion of the exon 4 seems to be repressed in differentiated H9c2 cells.

cancer biology↗

bioRxiv2019

Targeting of RBM10 to S1-1 Nuclear Bodies: Targeting Sequences and its Biological Significance

RBM10 is an RNA-binding protein that regulates alternative splicing (AS). It localizes to the extra-nucleolar nucleoplasm and S1-1 nuclear bodies (NBs) in the nucleus. We investigated the biological significance of this localization in relation to its molecular function. Our analyses, employing deletion mutants, revealed that RBM10 possesses two S1-1 NB-targeting sequences (NBTSs), one in the KEKE motif region and another in the C2H2 Zn finger (ZnF). These NBTSs act synergistically to localize RBM10 to S1-1 NBs. The C2H2 ZnF not only acts as an NBTS, but is also essential for AS regulation by RBM10. Moreover, RBM10 does not participate in S1-1 NB formation, and without alterations of RBM10 protein levels, its NB-localization changes, increasing as cellular transcriptional activity declines, and vice versa. These results indicate that RBM10 is a transient component of S1-1 NBs and is sequestered in NBs via its NBTSs when cellular transcription decreases. We propose that the C2H2 ZnF exerts its NB-targeting activity when RBM10 is unbound by pre-mRNAs, and that NB-localization of RBM10 is a mechanism to control its AS activity in the nucleus. Note that the previous title of this manuscript was Targeting of RBM10 to S1-1 Nuclear Bodies: Targeting Sequences and its Biological Significance.

molecular biology↗