We examined expression levels of PIK3CG, a catalytic subunit of phosphatidylinositide 3-OH kinase (PI3K), in colon cancer cells to investigate the hypothesis that PIK3CG might contribute to the growth and progression of colorectal cancers.
Our data further supports the role of PI3K/Akt signaling pathways in the pathogenesis of CRC and contributes to the identification of target molecules in the signal transduction pathway for cancer therapy.
Recently, mutations in PIK3CA, a member of the family of phosphatidylinositol 3'-kinase catalytic subunits, were identified in a significant fraction (25-30%) of colorectal cancers, gastric cancers, and glioblastomas and in a smaller fraction of breast and lung cancers.
Therefore, we investigated the effect of inhibiting the PI3K/AKT/IKK alpha pathway in regulating the inappropriate constitutive activation of NF kappa B and beta-catenin in CRC cell lines.
In colorectal carcinoma, PIK3CA mutations occur preferentially together with activating KRAS-BRAF mutations (MSI and MSS) while in gastric carcinomas PIK3CA mutations tend to occur as isolated events (MSI).
We analysed human colorectal cancers for genetic mutations in 340 serine/threonine kinases and found mutations in eight genes, including in three members of the phosphatidylinositol-3-OH kinase (PI(3)K) pathway.
These were generally found to be mutated in a mutually exclusive manner, thus increasing the mutation frequency of the pathway to 40% in colorectal cancers and emphasizing the importance of the PI3K pathway in tumorigenesis.
Therefore, the purpose of this study was 2-fold: 1) to analyze the distribution pattern of PI3K pathway components in human normal colorectal cancers, and 2) to determine whether targeted inhibition of PI3K inhibits colon cancer growth in vitro and suppresses metastatic growth in vivo.
Multiple logistic analysis showed that lymphatic invasion and RASSF2 methylation with KRAS, BRAF or PIK3CA mutation were independent risk factors for venous invasion in pT1 CRCs.
In this study, we aimed to examine the influence of PIK3CA mutation and K-Ras mutation on AKT activation, and to clarify whether PIK3CA mutation, K-Ras mutation and p-AKT expression may be used as parameters for predicting prognosis in colorectal cancer.
Because PIK3CA and its pathway are potential targets for chemotherapy and radiation therapy, and frequent somatic mutation of PIK3CA has been identified in many human cancer types (e.g., breast cancer, colorectal cancer), the abilities to detect PIK3CA mutations with enhanced sensitivities have great potential impacts on target therapies for many cancer types.
A high prevalence of genetic alterations in PI3K/AKT pathway in Saudi cohort of CRC, predominance of PIK3CA mutations in the MSI subgroup and their possible involvement in development/progression of this subset of CRC are some of the significant findings of our study.
We assayed DNA extracted from human tumors and detected PIK3CA mutation frequencies of 10.2% in colorectal cancer, 38.7% in breast cancer, 1.9% in lung cancer, and 2.9% in melanoma.
In conclusion, PIK3CA mutation is significantly associated with other key molecular events in colorectal cancer, and MGMT loss likely contributes to the development of PIK3CA G>A mutation.
The PIK3CA gene mutation was highly detected in normal imprinting tumors compared to colorectal cancers with insulin-like growth factor II loss of genomic imprinting (27.3% versus 6.7%).