Mechanism of Oncogenic Signal Activation by the Novel Fusion Kinase FGFR3–BAIAP2L1

Nakanishi, Yoshito; Akiyama, Nukinori; Tsukaguchi, Toshiyuki; Fujii, Toshihiko; Satoh, Yasuko; Ishii, Nobuya; Aoki, Masahiro

doi:10.1158/1535-7163.mct-14-0927-t

Cited by 55 publications

(54 citation statements)

References 34 publications

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“…For the spheroid formation assay, stably transfected Rat-2 cells were seeded to Nunclon Sphera Microplates (Thermo Scientific) and incubated for 7 or 21 days. Cell morphologies and cell viabilities were measured as previously described (33).…”

Section: Focus Formation Colony Formation and Spheroid Formation Asmentioning

confidence: 99%

Activating Mutations in PIK3CB Confer Resistance to PI3K Inhibition and Define a Novel Oncogenic Role for p110β

Nakanishi¹,

Walter²,

Spoerke³

et al. 2016

Cancer Research

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Activation of the PI3K pathway occurs commonly in a wide variety of cancers. Experience with other successful targeted agents suggests that clinical resistance is likely to arise and may reduce the durability of clinical benefit. Here, we sought to understand mechanisms underlying resistance to PI3K inhibition in PTEN-deficient cancers. We generated cell lines resistant to the pan-PI3K inhibitor GDC-0941 from parental PTEN-null breast cancer cell lines and identified a novel PIK3CB D1067Y mutation in both cell lines that was recurrent in cancer patients. Stable expression of mutant PIK3CB variants conferred resistance to PI3K inhibition that could be overcome by downstream AKT or mTORC1/2 inhibitors. Furthermore, we show that the p110b D1067Y mutant was highly activated and induced PIP3 levels at the cell membrane, subsequently promoting the localization and activation of AKT and PDK1 at the membrane and driving PI3K signaling to a level that could withstand treatment with proximal inhibitors. Finally, we demonstrate that the PIK3CB D1067Y mutant behaved as an oncogene and transformed normal cells, an activity that was enhanced by PTEN depletion. Collectively, these novel preclinical and clinical findings implicate the acquisition of activating PIK3CB D1067 mutations as an important event underlying the resistance of cancer cells to selective PI3K inhibitors.

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Section: Focus Formation Colony Formation and Spheroid Formation Asmentioning

confidence: 99%

Activating Mutations in PIK3CB Confer Resistance to PI3K Inhibition and Define a Novel Oncogenic Role for p110β

Nakanishi¹,

Walter²,

Spoerke³

et al. 2016

Cancer Research

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“…In a previous study, we analyzed the signaling pathway of an FGFR fusion kinases, FGFR3-BAIAP2L1 (15). A Rat-2 cell line stably expressing FGFR3-BAIAP2L1 exhibited potent tumorigenic activity.…”

Section: Introductionmentioning

confidence: 99%

ERK Signal Suppression and Sensitivity to CH5183284/Debio 1347, a Selective FGFR Inhibitor

Nakanishi¹,

Mizuno²,

Sase³

et al. 2015

Molecular Cancer Therapeutics

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Drugs that target specific gene alterations have proven beneficial in the treatment of cancer. Because cancer cells have multiple resistance mechanisms, it is important to understand the downstream pathways of the target genes and monitor the pharmacodynamic markers associated with therapeutic efficacy. We performed a transcriptome analysis to characterize the response of various cancer cell lines to a selective fibroblast growth factor receptor (FGFR) inhibitor (CH5183284/Debio 1347), a mitogen-activated protein kinase kinase (MEK) inhibitor, or a phosphoinositide 3-kinase (PI3K) inhibitor. FGFR and MEK inhibition produced similar expression patterns, and the extracellular signal-regulated kinase (ERK) gene signature was altered in several FGFR inhibitor-sensitive cell lines. Consistent with these findings, CH5183284/Debio 1347 suppressed phospho-ERK in every tested FGFR inhibitor-sensitive cell line. Because the mitogen-activated protein kinase (MAPK) pathway functions downstream of FGFR, we searched for a pharmacodynamic marker of FGFR inhibitor efficacy in a collection of cell lines with the ERK signature and identified dual-specificity phosphatase 6 (DUSP6) as a candidate marker. Although a MEK inhibitor suppressed the MAPK pathway, most FGFR inhibitor-sensitive cell lines are insensitive to MEK inhibitors and we found potent feedback activation of several pathways via FGFR. We therefore suggest that FGFR inhibitors exert their effect by suppressing ERK signaling without feedback activation. In addition, DUSP6 may be a pharmacodynamic marker of FGFR inhibitor efficacy in FGFR-addicted cancers.

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“…The fusion gene leads to a constitutive activation of the FGFR3 tyrosine kinase domain. An FGFR3-BAIAP2L1 fusion-positive cell line showed sensitivity to an FGFR inhibitor in vitro[50]. In this study, the FGFR3-BAIAP2L1 fusion gene was not examined.…”

Section: Discussionmentioning

confidence: 99%

“…The BAIAP2L1 gene is located on chromosome 7 at position 7q22.1, which is a different chromosome from the location of the FGFR3 gene. The FGFR3-BAIAP2L1 fusion has been detected by DNA-FISH, which is easily applied to clinical cases[10][50]. …”

Section: Discussionmentioning

confidence: 99%

Development of RNA-FISH Assay for Detection of Oncogenic FGFR3-TACC3 Fusion Genes in FFPE Samples

et al. 2016

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Introduction and ObjectivesOncogenic FGFR3-TACC3 fusions and FGFR3 mutations are target candidates for small molecule inhibitors in bladder cancer (BC). Because FGFR3 and TACC3 genes are located very closely on chromosome 4p16.3, detection of the fusion by DNA-FISH (fluorescent in situ hybridization) is not a feasible option. In this study, we developed a novel RNA-FISH assay using branched DNA probe to detect FGFR3-TACC3 fusions in formaldehyde-fixed paraffin-embedded (FFPE) human BC samples.Materials and MethodsThe RNA-FISH assay was developed and validated using a mouse xenograft model with human BC cell lines. Next, we assessed the consistency of the RNA-FISH assay using 104 human BC samples. In this study, primary BC tissues were stored as frozen and FFPE tissues. FGFR3-TACC3 fusions were independently detected in FFPE sections by the RNA-FISH assay and in frozen tissues by RT-PCR. We also analyzed the presence of FGFR3 mutations by targeted sequencing of genomic DNA extracted from deparaffinized FFPE sections.ResultsFGFR3-TACC3 fusion transcripts were identified by RNA-FISH and RT-PCR in mouse xenograft FFPE tissues using the human BC cell lines RT112 and RT4. These cell lines have been reported to be fusion-positive. Signals for FGFR3-TACC3 fusions by RNA-FISH were positive in 2/60 (3%) of non-muscle-invasive BC (NMIBC) and 2/44 (5%) muscle-invasive BC (MIBC) patients. The results of RT-PCR of all 104 patients were identical to those of RNA-FISH. FGFR3 mutations were detected in 27/60 (45%) NMIBC and 8/44 (18%) MIBC patients. Except for one NMIBC patient, FGFR3 mutation and FGFR3-TACC3 fusion were mutually exclusive.ConclusionsWe developed an RNA-FISH assay for detection of the FGFR3-TACC3 fusion in FFPE samples of human BC tissues. Screening for not only FGFR3 mutations, but also for FGFR3-TACC3 fusion transcripts has the potential to identify additional patients that can be treated with FGFR inhibitors.

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Mechanism of Oncogenic Signal Activation by the Novel Fusion Kinase FGFR3–BAIAP2L1

Cited by 55 publications

References 34 publications

Activating Mutations in PIK3CB Confer Resistance to PI3K Inhibition and Define a Novel Oncogenic Role for p110β

Activating Mutations in PIK3CB Confer Resistance to PI3K Inhibition and Define a Novel Oncogenic Role for p110β

ERK Signal Suppression and Sensitivity to CH5183284/Debio 1347, a Selective FGFR Inhibitor

Development of RNA-FISH Assay for Detection of Oncogenic FGFR3-TACC3 Fusion Genes in FFPE Samples

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