Protein tyrosine phosphatase SHP-1 sensitizes EGFR/HER-2 positive breast cancer cells to trastuzumab through modulating phosphorylation of EGFR and HER-2

SHP-1 acts as a tumor suppressor by interacting with EGFR and predicts the prognosis of human breast cancer

OBJECTIVE

The aims of this study were to examine the prognostic value of SHP-1 in breast cancer, its roles in the regulation of breast cancer cell growth and metastasis, and the underlying mechanisms.

METHODS

Tumor specimens from 160 patients with breast cancer and 160 noncancerous tissues were used to examine the expression of SHP-1 and to analyze its association with overall survival through Kaplan-Meier and multivariate Cox regression analyses. RNA sequencing data and the expression and clinical importance of SHP-1 in breast cancer were evaluated with data from The Cancer Genome Atlas. In vitro and in vivo assays were performed to elucidate the effects of SHP-1 on breast cancer cell proliferation and invasion. Confocal immunofluorescence and GST pulldown assays were used to demonstrate the interaction between SHP-1 and epidermal growth factor receptor, as well as its downstream pathways. Immunohistochemistry and The Cancer Genome Atlas database were used to investigate the clinical association between SHP-1 and EGFR in human breast cancer.

RESULTS

SHP-1 expression was associated with better survival in patients with breast cancer, whereas SHP-1 expression was negatively correlated with EGFR in human breast cancer. Ectopic SHP-1 expression significantly suppressed breast cancer cell proliferation, migration, and invasion. SHP-1 knockdown induced a more invasive phenotype and accelerated cell growth. Mechanistically, EGFR, a protein directly interacting with SHP-1, mediates the SHP-1-induced inactivation of Ras/Erk/GSK3β signaling and its downstream effectors.

CONCLUSIONS

SHP-1 is an important prognostic biomarker in patients with breast cancer, and the SHP-1-EGFR axis is a promising target for treatment.

Novel Human Bispecific Aptamer-Antibody Conjugates for Efficient Cancer Cell Killing

Monoclonal antibodies have been approved by the Food and Drug Administration for the treatment of various human cancers. More recently, oligonucleotide aptamers have risen increasing attention for cancer therapy thanks to their low size (efficient tumor penetration) and lack of immunogenicity, even though the short half-life and lack of effector functions still hinder their clinical applications. Here, we demonstrate, for the first time, that two novel bispecific conjugates, consisting of an anti-epidermal growth factor receptor (EGFR) aptamer linked either with an anti-epidermal growth factor receptor 2 (ErbB2) compact antibody or with an immunomodulatory (anti-PD-L1) antibody, were easily and rapidly obtained. These novel aptamer-antibody conjugates retain the targeting ability of both the parental moieties and acquire a more potent cancer cell killing activity by combining their inhibitory properties. Furthermore, the conjugation of the anti-EGFR aptamer with the immunomodulatory antibody allowed for the efficient redirection and activation of T cells against cancer cells, thus dramatically enhancing the cytotoxicity of the two conjugated partners. We think that these bispecific antibody-aptamer conjugates could have optimal biological features for therapeutic applications, such as increased specificity for tumor cells expressing both targets and improved pharmacokinetic and pharmacodynamic properties due to the combined advantages of the aptamer and antibody.

Novel treatment strategies for patients with HER2-positive breast cancer who do not benefit from current targeted therapy drugs

Human epidermal growth factor receptor-2 positive breast cancer (HER2+ BC) is characterized by a high rate of metastasis and drug resistance. The advent of targeted therapy drugs greatly improves the prognosis of HER2+ BC patients. However, drug resistance or severe side effects have limited the application of targeted therapy drugs. To achieve more effective treatment, considerable research has concentrated on strategies to overcome drug resistance. Abemaciclib (CDK4/6 inhibitor), a new antibody-drug conjugate (ADC), src homology 2 (SH2) containing tyrosine phosphatase-1 (SHP-1) and fatty acid synthase (FASN) have been demonstrated to improve drug resistance. In addition, using an effective vector to accurately deliver drugs to tumors has shown good application prospects. Many studies have also found that natural anti-cancer substances produced effective results during in vitro and in vivo anti-HER2+ BC research. This review aimed to summarize the current status of potential clinical drugs that may benefit HER2+ BC patients in the future.