Association between gain-of-function mutations in PIK3CA and resistance to HER2-targeted agents in HER2-amplified breast cancer cell lines

Kataoka, Yu; Mukohara, Toru; Shimada, Hideaki; Saijo, Nagahiro; Hirai, Mitsuharu; Minami, Hironobu

doi:10.1093/annonc/mdp304

Cited by 204 publications

(158 citation statements)

References 36 publications

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“…(44) NF-kB activation in breast cancer cells has been shown to increase trastuzumab resistance, (45) supporting the idea of NF-kB as a potential target in trastuzumab-resistant breast cancers. Our results of significant nuclear accumulation of p65 (RelA), the most predominant active complex of NF-kB family in epithelial cells in association with p50 subunit, indicate that NF-kB pathway is functional in resistant cells.…”

Section: Mechanism Of Nf-jb Activation In Trastuzumab-resistant Cellsmentioning

confidence: 81%

“…Moreover, the up-regulation of the HER2 downstream signal pathway is another cause of trastuzumab resistance. PTEN loss (36,53) has been implicated in trastuzumab resistance by increasing PI3K/Akt (33,45) and activating IL-6 to mediate cancer stem cells. (29) Our data have established that the activation of PI3K/Akt pathway is sensitive to the NFkB inhibitor in resistant cells.…”

Section: Mechanism Of Nf-jb Activation In Trastuzumab-resistant Cellsmentioning

confidence: 99%

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Trastuzumab-Resistant Luminal B Breast Cancer Cells Show Basal-Like Cell Growth Features Through NF-κB-Activation

Kanzaki

Mukhopadhya

Cui

et al. 2016

Monoclonal Antibodies in Immunodiagnosis and Immunotherapy

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A major clinical problem in the treatment of breast cancer is mortality due to metastasis. Understanding the molecular mechanisms associated with metastasis should aid in designing new therapeutic approaches for breast cancer. Trastuzumab is the main therapeutic option for HER2+ breast cancer patients; however, the molecular basis for trastuzumab resistance (TZR) and subsequent metastasis is not known. Earlier, we found expression of basal-like molecular markers in TZR tissues from patients with invasive breast cancer. (1) The basal-like phenotype is a particularly aggressive form of breast cancer. This observation suggests that TZR might contribute to an aggressive phenotype. To understand if resistance to TZR can lead to basal-like phenotype, we generated a trastuzumab-resistant human breast cancer cell line (BT-474-R) that maintained human epidermal growth factor receptor 2 (HER2) overexpression and HER2 mediated signaling. Analysis showed that nuclear factor-kappa B (NF-kB) was constitutively activated in the BT-474-R cells, a feature similar to the basal-like tumor phenotype. Pharmacologic inhibition of NF-kB improved sensitivity of BT-474-R cells to trastuzumab. Interestingly, activation of HER2 independent NF-kB is not shown in luminal B breast cancer cells. Our study suggests that by activating the NF-kB pathway, luminal B cells may acquire a HER2+ basal-like phenotype in which NF-kB is constitutively activated; this notion is consistent with the recently proposed ''progression through grade'' or ''evolution of resistance'' hypothesis. Furthermore, we identified IKK-a/IKK-b and nuclear accumulation of RelA/p65 as the major determinants in the resistant cells. Thus our study additionally suggests that the nuclear accumulation of p65 may be a useful marker for identifying metastasis-initiating tumor cells and targeting RelA/p65 may limit metastasis of breast and other cancers associated with NF-kB activation.

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Section: Mechanism Of Nf-jb Activation In Trastuzumab-resistant Cellsmentioning

confidence: 81%

Section: Mechanism Of Nf-jb Activation In Trastuzumab-resistant Cellsmentioning

confidence: 99%

Trastuzumab-Resistant Luminal B Breast Cancer Cells Show Basal-Like Cell Growth Features Through NF-κB-Activation

Kanzaki

Mukhopadhya

Cui

et al. 2016

Monoclonal Antibodies in Immunodiagnosis and Immunotherapy

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“…Albeit the impact of these mutations concerning patient outcome is not completely clear yet, it has been reported that PI3K hyperactivity contributes to a lower response to trastuzumab and lapatinib treatment in patients with HER2-positive tumors (Berns et al, 2007;Eichhorn et al, 2008;Serra et al, 2008;Kataoka et al, 2010) as well as to resistance to anti-estrogen therapies. Furthermore, mutations regarding exon 20 of PIK3CA have been associated with poor prognosis (Lai et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

“…T47D cells carry a point mutation in exon 20 leading to an amino acid change at position 1047 (H1047R). Finally, SKBR-3 cells were reported to exhibit no PIK3CA mutations at these positions (Hollestelle et al, 2007;Jensen et al, 2011;Kataoka et al, 2010;Weigelt et al, 2011). In the beginning, primer sets for exon amplification described in Hurst et al (2009) were used but gave non-satisfying results within our setting.…”

Section: 2mentioning

confidence: 94%

“…SKBR-3 cells were reported to contain a PIK3CA wild-type gene, while MCF-7 and T47D cells harbor heterozygous hotspot mutations in the PIK3CA gene: MCF-7 is mutated in exon 9 (E545K), T47D in exon 20 (H1047R) (Hollestelle et al, 2007;Jensen et al, 2011;Kataoka et al, 2010;Weigelt et al, 2011). All cell lines were cultured in RPMI 1640 containing 10% fetal calf serum and 1% PenicillinStreptomycin (all Gibco, Karlsruhe, Germany).…”

Section: Cell Lines and Cell Culturementioning

confidence: 99%

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Analysing the Mutational Status of PIK3CA in Circulating Tumor Cells from Metastatic Breast Cancer Patients

Schneck¹,

Blassl²,

Meier-Stiegen³

et al. 2013

Senologie - Zeitschrift für Mammadiagnostik und -therapie

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Metastatic breast cancer PIK3CA mutations SNaPshot assay A B S T R A C TThe frequently altered phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathway is involved in the regulation of cellular processes required for breast carcinogenesis. The aim of the project was to develop a method to identify hotspot mutations in the PIK3CA gene in circulating tumor cells (CTCs) of metastatic breast cancer (metBC) patients.From 44 enrolled CTC-positive metBC patients a total number of 57 peripheral blood samples were analysed by CellSearch Ò . Genomic DNA of enriched CTCs was isolated, amplified and analyzed for PIK3CA mutations in exons 9 and 20 which lead to E542K, E545K or H1047R amino acid changes and result in increased PI3K activity. The mutations were detected by using SNaPshot-methodology comprising PCR amplification and single nucleotide primer extension.SNaPshot analysis was established using genomic DNA from different breast cancer cell lines and then successfully transferred to investigate blood samples and single cells. Overall, twelve hotspot mutations in either exon 9/E545K (6/12, 50%) or exon 20/H1047R (6/12, 50%) could be determined within 9 out of 57 (15.8%) blood samples from 7 out of 44 (15.9%) patients; CTC counts ranged from 1 to 9748. PIK3CA variants E542K, E545G and E545A were not detected.Analysing the PIK3CA genotype of CTCs has clinical relevance with respect to drug resistance, e.g. against HER2-targeted therapy. The herein described approach including SNaPshot technology provides a simple method to characterize hotspot mutations within CTCs Abbreviations: APC, allophycocyanin; CK-PE, cytokeratin-phycoerythrin; CS, CellSearch Ò ; CTC(s), circulating tumor cell(s); DAPI, 4,6-diamidino-2-phenylindole; DTCs, disseminated tumor cells; ER, estrogen receptor; FITC, fluorescein-isothiocyanate; HER2, human epidermal growth factor receptor 2; PI3K, phosphatidylinositol-3-kinase; PTEN, phosphatase and tensin homolog; PR, progesterone receptor; SNP, single nucleotide polymorphism; WGA, Whole Genome Amplification.* Corresponding author.

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T‐DM1, a novel antibody–drug conjugate, is highly effective against primary HER2 overexpressing uterine serous carcinoma in vitro and in vivo

et al. 2014

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Amplification of c-erbB2 has been reported in over 30% of uterine serous carcinoma (USC) and found to confer poor survival because of high proliferation and increased resistance to therapy. In this study, we evaluated for the first time Trastuzumab emtansine (T-DM1), a novel antibody–drug conjugate, against multiple epidermal growth factor receptor-2 (HER2)-positive USC cells in vitro followed by developing a supportive in vivo model. Fifteen primary USC cell lines were assessed by immunohistochemistry (IHC) and flow cytometry for HER2 protein expression. C-erbB2 gene amplification was evaluated using fluorescent in situ hybridization. Sensitivity to T-DM1 and trastuzumab (T)-induced antibody-dependent cell-mediated cytotoxicity was evaluated in 5-h chromium release assays. T-DM1 and T cytostatic and apoptotic activities were evaluated using flow-cytometry-based proliferation assays. In vivo activity of T-DM1 versus T in USC xenografts in SCID mice was also evaluated. High levels of HER2 protein overexpression and HER2 gene amplification were detected in 33% of USC cell lines. T-DM1 was considerably more effective than trastuzumab in inhibiting cell proliferation and in causing apoptosis (P = 0.004) of USC showing HER2 overexpression. Importantly, T-DM1 was highly active at reducing tumor formation in vivo in USC xenografts overexpressing HER2 (P = 0.04) and mice treated with TDM-1 had significantly longer survival when compared to T-treated mice and control mice (P ≤ 0.0001). T-DM1 shows promising antitumor effect in HER2-positive USC cell lines and USC xenografts and its activity is significantly higher when compared to T. T-DM1 may represent a novel treatment option for HER2-positive USC patients with disease refractory to trastuzumab and traditional chemotherapy.

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Association between gain-of-function mutations in PIK3CA and resistance to HER2-targeted agents in HER2-amplified breast cancer cell lines

Abstract: PIK3CA mutations are associated with resistance to HER2-targeted agents. PI3K inhibitors are potentially effective in overcoming trastuzumab resistance caused by PIK3CA mutations. S6K phosphorylation is a possibly useful pharmacodynamic marker in HER2-targeted therapy.

Cited by 204 publications

References 36 publications

Trastuzumab-Resistant Luminal B Breast Cancer Cells Show Basal-Like Cell Growth Features Through NF-κB-Activation

Trastuzumab-Resistant Luminal B Breast Cancer Cells Show Basal-Like Cell Growth Features Through NF-κB-Activation

Analysing the Mutational Status of PIK3CA in Circulating Tumor Cells from Metastatic Breast Cancer Patients

T‐DM1, a novel antibody–drug conjugate, is highly effective against primary HER2 overexpressing uterine serous carcinoma in vitro and in vivo

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