ABSTRACT
Events including antibody‒antigen affinity, internalization, trafficking and lysosomal proteolysis combinatorially determine the efficiency of antibody-drug conjugate (ADC) catabolism and hence the toxicity. Nevertheless, an approach that conveniently identifies proteins requisite for payload release and the ensuing toxicity for mechanistic studies and quality assessment is lacking. Considering the plethora of ADC candidates under development, we developed a target-responsive subcellular catabolism (TARSC) approach that examines ADC catabolism and probes changes in response to targeted interferences of proteins of interest. We firstly applied TARSC to study the commercial T-DM1 and the biosimilar. We recorded unequivocal catabolic behaviors regardless of the absence and presence of the targeted interferences. Their negligible differences in TARSC profiles agreed with their undifferentiated anti-tumoral efficacy according to further
ABSTRACT
@#Breast cancer is the leading cause of cancer-related death in female worldwide. Human epidermal growth factor receptor 2 (HER2) amplification is observed in approximately 20% of breast cancer cases and is associated with poor clinical outcomes. Dual HER2 blockade without chemotherapy represents an attractive therapeutic approach, and it remains unresolved if anti-HER2 therapeutic antibodies are sufficient to replace chemotherapy regimens. In this review, we discuss the approved therapeutic monoclonal antibodies (pertuzumab and trastuzumab) and antibody-drug conjugate (trastuzumab emtansine or T-DM1) for the treatment of HER2-positive breast cancer patients. In summary, phase II and III clinical trials have demonstrated that dual HER2 blockade (pertuzumab and trastuzumab) plus chemotherapy regimens confer better efficacy compared with dual HER2 blockade alone, or anti-HER2 antibody monotherapy, in HER2-positive breast cancer patients. Dual HER2 blockade (pertuzumab and trastuzumab) combined with chemotherapies (5-fluorouracil, epirubicin, cyclophosphamide and docetaxel) yield superior response. Moreover, dual HER2 blockade (T-DM1 and pertuzumab) in combination with docetaxel represents a promising treatment regimen containing T-DM1. Ongoing clinical trials are assessing the optimal chemotherapy of choice with anti-HER2 antibodies combinations. In conclusion, improved outcomes are attributable to selection for the optimal chemotherapy regimen in combination with anti-HER2 antibodies instead of replacing chemotherapy altogether with the current line of anti-HER2 therapeutic antibodies.
ABSTRACT
OBJECTIVE: To investigate the different biological effects of trastuzumab and T-DM1 on BT-474 and HCC1954 cell lines. METHODS: Flow cytometry was employed to study the expression level of HER2 on the two cell lines. ELISA was used to check the binding ability of trastuzumab and T-DM1 with HER2 antigen. With cell proliferation inhibition and killing methods, the dose-response curves were explored to demonstrate the biological effects of trastuzumab and T-DM1 on the two cell lines. RESULTS: HER2 were highly expressed in both of the two cell lines. The HER2 binding ability was highly similar between trastuzumab and T-DM1. Trastuzumab could inhibit the proliferation of BT474 but not HCC1954, while T-DM1 could kill both kinds of cells. CONCLUSION: In the in vitro cell models, T-DM1 can play biological effect in HER2 highly expressed but trastuzumab-resistant cell lines.
ABSTRACT
T-DM1 is a novel antibody-drug conjugate that has similar biological activity with that of trastuzumab. T-DM1 specifically delivers DM1, the effective anti-microtubule drug, into the cytoplasm of tumor cells with HER2 overexpression. The efficacy of T-DM1 monotherapy is better than lapatinib in combination with capecitabine and T-DM and is expected to become the standard second-line treatment for HER2-positive advanced breast cancer drugs. Clinical trials that compare T-DM1 with trastuzumab joint taxane as the first-line of treatment for advanced breast cancer trials are currently being performed. T-DM1 is a brand new anti-HER2 drug after trastuzumab. U.S. FDA already approved T-DM1 as a drug for the treatment of HER2-positive advanced breast cancer patients.