Correlation Between Onco-suppressors PTEN and NM23 and Clinical Outcome in Patients With T1 Breast Cancer

The effects of the tumor suppressor gene PTEN on the proliferation and apoptosis of breast cancer cells via AKT phosphorylation

Background

The proliferation and apoptosis of cancer cells play important roles in breast carcinomas. However, to date, there have been few reports on the correlation between the expression of PTEN and AKT phosphorylation in breast cancer. This present study investigated the effects of the phosphatase and tensin homology deleted from chromosome 10 (PTEN) gene on the proliferation and apoptosis of breast cancer cells through protein kinase B (AKT) phosphorylation.

Methods

Human breast cancer MDA-MB-231 cells were transfected with the pcDNA3.0 control vector or the pcDNA3.0-PTEN vector for 48 hours. The Cell Counting Kit 8 (CCK-8) was used to detect cell survival rates, double staining was performed to detect apoptosis, and Western blot (WB) analysis was conducted to detect protein expression. The effects of PTEN expression on the cell cycle and apoptosis of human breast cancer cell line MDA-MB-231, and on the levels of phosphorylated AKT protein were further analyzed. Moreover, the relationship between the PTEN gene and clinical features were also analyzed.

Results

The cell survival rate of cells transfected with pcDNA3.0-PTEN was significantly lower than that of cells transfected with the control pcDNA3.0 vector (55.65%±12.18% vs. 97.32%±12.45%, P=0.004). Compared with the pcDNA3.0 group, the apoptosis rate of the pcDNA3.0-PTEN group was significantly increased (20.65±2.18 vs. 2.32±0.45, P=0.001). The expression of PTEN protein in pcDNA3.0-PTEN group was higher than that in the pcDNA3.0 group, and the expression of the AKT and mTOR proteins was significantly lower than that in pcDNA3.0 group (P<0.05). The expression of PTEN in the lymph node metastasis positive group was significantly higher than that in the lymph node metastasis negative group (P<0.05). The expression of the AKT protein in breast cancer was higher than that in normal breast tissue, and the difference was statistically significant (P<0.01).

Conclusions

Overexpression of the PTEN gene can promote AKT phosphorylation, increase the apoptotic index of breast cancer cells, and reduce the proliferative activity of breast cancer cells. This provided a new direction for the next treatment of breast cancer, but further clinical research is needed.

Sentinel Lymph Node Detection in Breast Cancer: An Innovative Technique

(1) Background: Sentinel lymph node biopsy is important in the search for metastases, especially in patients with malignant breast disease. Our study proposed new techniques to prevent complications such as possible postoperative seroma formation, pain or hypoesthesia of the axillary cord and medial arm surface, as well as motor deficits, to avoid disabling outcomes and presents initial data from our experience with the sentinel lymph node biopsy technique. (2) Methods: We mainly used two radioactive tracer detection techniques and a new technique using a radiotracer called Sentimag-magtrace. The positive lymph node was located and removed to perform histologic analysis. In our study, we evaluate 100 patients who underwent breast cancer surgery. (3) Results: We calculated the identification rates of the different methods of sentinel lymph node detection and found that it was 88.9% using radioactive tracers vs. 89.5% using the magnetic tracer technology (Sentimag). (4) Conclusions: Thus, this technique avoids radiation exposure for both patients and health care providers, and can reduce costs and time.

Phosphatase and Tensin Homolog Deleted on Chromosome Ten (PTEN) Derived from Bone Marrow Stromal Cells Promotes the Development of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) remains a threat to women’s life with a lack of targeted therapy. This study aimed to explore the role of PTEN derived from BMSCs in TNBC. We carried out a retrospective analysis of 65 TNBC patients and 30 healthy subjects from October 2016 to January 2021 with a 10-year follow up. PTEN expression in TNBC tissues and cells was determined by RTqPCR. Functional experiments were conducted to evaluate PTEN’s effect on TNBC cell biological behaviors using MTT assay and Transwell assay, as well as on PI3K-Akt-HIF-1α-VEGF signaling transduction. PTEN was up-regulated in TNBC tissues relative to healthy controls and it was negatively associated with the survival rate. In in vitro experiments, PTEN overexpression increased cell viability and invasion and knocking down of PTEN exerted opposite effect. The expression of PI3K was directly regulated by PTEN. Up-regulation of PTEN resulted in a decline in HIF-1α, Akt and VEGF expressions, which were elevated after knocking down of PTEN. In conclusion, PTEN derived from BMSCs promotes TNBC cell development through blocking PI3K-Akt-HIF-1α-VEGF signaling pathway, providing a new theoretical basis for targeted therapy of TNBC.