In PTEN-mutated tumors, we show that PI3Kα activity is suppressed and PI3K signaling is driven by PI3Kβ. A selective inhibitor of PI3Kβ inhibits the Akt/mTOR pathway in these tumors but not in those driven by receptor tyrosine kinases. However, inhibition of PI3Kβ only transiently inhibits Akt/mTOR signaling because it relieves feedback inhibition of IGF1R and other receptors and thus causes activation of PI3Kα and a rebound in downstream signaling. This rebound is suppressed and tumor growth inhibition enhanced with combined inhibition of PI3Kα and PI3Kβ. In PTEN-deficient models of prostate cancer, this effective inhibition of PI3K causes marked activation of androgen receptor activity. Combined inhibition of both PI3K isoforms and androgen receptor results in major tumor regressions.
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http://dx.doi.org/10.1016/j.ccell.2014.11.008 | DOI Listing |
Front Oncol
December 2024
Gynecologic Oncology, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
Hum Pathol
April 2024
Department of Pathology and Laboratory Medicine, Alpert Medical School of Brown University, Staff Pathologist, Women & Infants Hospital, 101 Dudley Street, Providence, RI, 02903, USA.
Deleterious germline mutations in multiple genes confer an increased breast cancer (BC) risk. Immunohistochemical (IHC) expression of protein products of mutated high-risk genes has not been investigated in BC. We hypothesized that pathogenic mutations may lead to an abnormal IHC expression pattern in the tumor cells.
View Article and Find Full Text PDFJCO Precis Oncol
August 2023
Department of Neurosurgery, McGovern Medical School, The University of Texas Health Science Center, Houston, TX.
Cancer
June 2023
Merck & Co., Inc., Rahway, New Jersey, USA.
Background: In this first-in-human phase 1b study (ClinicalTrials.gov identifier NCT02761694) of advanced solid tumors with PIK3CA/AKT/PTEN mutations, the authors investigated the safety and efficacy of the pan-AKT inhibitor vevorisertib (MK-4440; ARQ 751) as monotherapy or with paclitaxel or fulvestrant.
Methods: Patients with histologically confirmed, advanced or recurrent, PIK3CA/AKT/PTEN-mutated solid tumors, measurable disease according to Response Evaluation Criteria in Solid Tumors, version 1.
Lab Invest
May 2023
Université de Poitiers, CHU de Poitiers, ProDiCeT, Poitiers, France; Laboratoire de Cancérologie Biologique, CHU de Poitiers, Poitiers, France. Electronic address:
Gliomas are the most common and lethal primary brain tumors in adults. Glioblastomas, the most frequent and aggressive form of gliomas, represent a therapeutic challenge as no curative treatment exists to date, and the prognosis remains extremely poor. Recently, the transcriptional cofactors Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) belonging to the Hippo pathway have emerged as a major determinant of malignancy in solid tumors, including gliomas.
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