Leukemogenic kinase FIP1L1‐PDGFRA and a small ubiquitin‐like modifier E3 ligase, PIAS1, form a positive cross‐talk through their enzymatic activities

Abstract

Fusion tyrosine kinases play a crucial role in the development of hematological malignancies. FIP1L1‐PDGFRA is a leukemogenic fusion kinase that causes chronic eosinophilic leukemia. As a constitutively active kinase, FIP1L1‐PDGFRA stimulates downstream signaling molecules, leading to cellular proliferation and the generation of an anti‐apoptotic state. Contribution of the N‐terminal FIP1L1 portion is necessary for FIP1L1‐PDGFRA to exert its full transforming activity, but the underlying mechanisms have not been fully characterized. We identified PIAS1 as a FIP1L1‐PDGFRA association molecule by yeast two‐hybrid screening. Our analyses indicate that the FIP1L1 portion of FIP1L1‐PDGFRA is required for efficient association with PIAS1. As a consequence of the association, FIP1L1‐PDGFRA phosphorylates PIAS1. Moreover, the kinase activity of FIP1L1‐PDGFRA stabilizes PIAS1. Therefore, PIAS1 is one of the downstream targets of FIP1L1‐PDGFRA. Moreover, we found that PIAS1, as a SUMO E3 ligase, sumoylates and stabilizes FIP1L1‐PDGFRA. In addition, suppression of PIAS1 activity by a knockdown experiment resulted in destabilization of FIP1L1‐PDGFRA. Therefore, FIP1L1‐PDGFRA and PIAS1 form a positive cross‐talk through their enzymatic activities. Suppression of sumoylation by ginkgolic acid, a small molecule compound inhibiting a SUMO E1‐activating enzyme, also destabilizes FIP1L1‐PDGFRA, and while the tyrosine kinase inhibitor imatinib suppresses FIP1L1‐PDGFRA‐dependent cell growth, ginkgolic acid or siRNA of PIAS1 has a synergistic effect with imatinib. In conclusion, our results suggest that sumoylation by PIAS1 is a potential target in the treatment of FIP1L1‐PDGFRA‐positive chronic eosinophilic leukemia.

Utilisation of semiconductor sequencing for detection of actionable fusions in solid tumours

“…In contrast, less prevalent actionable fusions exhibited tumour type specificity including CCDC6-RET fusions in thyroid and lung cancer, FGFR2-BICC1 in cholangiocarcinoma, PTPRZ1-MET in glioblastoma, EIF3E-RSPO2 and PTPRK-RSPO3 in colorectal cancer and KIF5B-RET in NSCLC as previously reported [3,[25][26][27][28]. Other low frequency actionable fusions namely, AGK-BRAF, FIP1L1-PDGFRA, FNDC3B-PIK3CA, RET-NCOA4, SND1-BRAF, TMEM178B-MET, TMEM178B-BRAF, KANK1-NTRK3, EIF3E-RSPO2 and PTPRK -RSPO3 have been previously reported as rare fusions in tumours of other type [1,[28][29][30][31][32][33][34]. Non targeted novel fusions were also identified including FGFR1-NRG1 in breast,…”

Intestinal Lymphatic Endothelial Cells Produce R-Spondin3

“…The small intestine was lysed in RIPA buffer (50 mM Tris–HCl (pH 8.0), 150 mM NaCl, 1% NP-40, 0.1% SDS, 0.5% sodium deoxycholate, 5 mM EDTA, 0.1% Triton X-100) supplemented with 50 mM N-ethylmaleimide, 10 μg/ml aprotinin, 50 μg/ml leupeptin, 100 mM NaF and 1 mM Na3VO4. Western blotting was performed as previously described 35 . Proteins were separated by SDS-PAGE and transferred onto nitrocellulose membranes and detected with antibodies shown in Supplementary Table 1 .…”

Utilisation of semiconductor sequencing for detection of actionable fusions in solid tumors

“…A proportion of low frequency fusions did however exhibit tumour type specificity including CCDC6-RET fusions in thyroid and lung cancer, FGFR2-BICC1 in cholangiocarcinoma, PTPRZ1-MET in glioblastoma, EIF3E-RSPO2 and PTPRK-RSPO3 in colorectal cancer and KIF5B-RET in NSCLC [24][25][26][27][28]. Other low frequency fusions namely, AGK-BRAF, FIP1L1-PDGFRA, FNDC3B-PIK3CA, RET-NCOA4, SND1-BRAF, TMEM178B-MET, TMEM178B-BRAF, KANK1-NTRK3, EIF3E-RSPO2 and PTPRK -RSPO3 have been previously reported as rare fusions in tumours of other type [27,[29][30][31][32][33][34][35]. Non targeted novel fusions were also identified including FGFR1-NRG1 in breast, BRAF-MRPS33 in prostate, SND1-MET in lung, PCM1-BRAF in sarcoma and TMEM178B-MET in rectal cancer.…”