Effects of AKT1 E17K mutation hotspots on the biological behavior of breast cancer cells

OBJECTIVE

To investigate the effect of the AKT1 gene mutation hotspot E17K on the growth, proliferation, survival, and migration of breast cancer cells, based on the survival and prognosis of breast cancer patients with the AKT1 E17K mutation shown in TCGA database.

METHODS

The survival and incidence rates of AKT1 E17K mutation hotspots in breast cancer and other cancers were extracted from the Cancer Genome Atlas (TCGA). The recombinant eukaryotic expression plasmid AKT1 E17K-pIRES2-EGFP was constructed and transfected into breast cancer MCF-7, and MDA-MB-231 cell lines. MCF-7 and MDA-MB-231 cell lines were randomly divided into blank control groups, empty plasmid groups, and recombinant plasmid groups. The growth curve was drawn using the cell counting method. The proliferation and division of breast cancer cells were detected by CFSE fluorescent dye tracking. Apoptosis was detected by Annexin V/PI double labeling and cell vitality was detected using MTT assays, and cell migratory ability was detected by cell scratch and transwell chamber tests.

RESULTS

In breast cancer, and other cancers, the overall survival rate of patients with an AKT E17K mutation was higher than that of patients with non-point mutation, and this mutation was the most common found in breast cancer. Compared with the wild type, the growth function of mutant MCF-7 cells was inhibited (P < 0.05), as was the proliferation of MCF-7 cells expressing the AKT1 E17K mutation gene (P < 0.001). The late apoptosis rate of mutant breast cancer cells increased (P < 0.05) and the viability was lower than that of wild-type cells (P < 0.05). Mutant MDA-MB-231 cells showed increased migration ability when compared to wild-type MDA-MB-231 cells (P < 0.05).

CONCLUSIONS

The expression of the AKT1 E17K mutation hotspot can inhibit the growth, proliferation, and survival ability of breast cancer cells, and promote apoptosis, while it also improves their migratory ability. The survival and prognosis of breast cancer patients with this mutation are good, which may be related to the inhibition of the PI3K/AKT/mTOR signaling pathway.

A Rapid Robust Method for Subgrouping Non-NF2 Meningiomas According to Genotype and Detection of Lower Levels of M2 Macrophages in AKT1 E17K Mutated Tumours

The majority of meningiomas are grade I, but some grade I tumours are clinically more aggressive. Recent advances in the genetic study of meningiomas has allowed investigation into the influence of genetics on the tumour microenvironment, which is important for tumorigenesis. We have established that the endpoint genotyping method Kompetitive Allele Specific PCR (KASP™) is a fast, reliable method for the screening of meningioma samples into different non-NF2 mutational groups using a standard real-time PCR instrument. This genotyping method and four-colour flow cytometry has enabled us to assess the variability in the largest immune cell infiltrate population, M2 macrophages (CD45+HLA-DR+CD14+CD163+) in 42 meningioma samples, and to suggest that underlying genetics is relevant. Further immunohistochemistry analysis comparing AKT1 E17K mutants to WHO grade I NF2-negative samples showed significantly lower levels of CD163-positive activated M2 macrophages in meningiomas with mutated AKT1 E17K, signifying a more immunosuppressive tumour microenvironment in NF2 meningiomas. Our data suggested that underlying tumour genetics play a part in the development of the immune composition of the tumour microenvironment. Stratifying meningiomas by mutational status and correlating this with their cellular composition will aid in the development of new immunotherapies for patients.