Cooperative antitumor activities of carnosic acid and Trastuzumab in ERBB2+ breast cancer cells

Abstract

BackgroundERBB2 is overexpressed in up to 20–30% of human breast cancers (BCs), and it is associated with aggressive disease. Trastuzumab (Tz), a humanized monoclonal antibody, improves the prognosis associated with ERBB2-amplified BCs. However, the development of resistance remains a significant challenge. Carnosic acid (CA) is a diterpene found in rosemary and sage, endowed with anticancer properties. In this in vitro study, we have investigated whether Tz and CA have cooperative effects on cell survival of ERBB2 overexpressing (ERBB2+) cells and whether CA might restore Tz sensitivity in Tz-resistant cells.MethodsWe have studied BC cell migration and survival upon CA and Tz treatment. In particular, migration ability was assessed by transwell assay while cell survival was assessed by MTT assay. In addition, we have performed cell cycle and apoptosis analysis by high-resolution DNA flow cytometry and annexin-V, resazurin and sytox blue staining by flow cytometry, respectively. The expression of proteins involved in cell cycle progression, ERBB2 signaling pathway, and autophagy was evaluated by immunoblot and immunofluorescence analysis. Cellular structures relevant to the endosome/lysosome and autophagy pathways have been studied by immunofluorescence and transmission electron microscopy.ResultsWe report that, in ERBB2+ BC cells, CA reversibly enhances Tz inhibition of cell survival, cooperatively inhibits cell migration and induces cell cycle arrest in G0/G1. These events are accompanied by ERBB2 down-regulation, deregulation of the PI3K/AKT/mTOR signaling pathway and up-regulation of both CDKN1A/p21WAF1 and CDKN1B/p27KIP1. Furthermore, we have demonstrated that CA impairs late autophagy and causes derangement of the lysosomal compartment as shown by up-regulation of SQSTM1/p62 and ultrastructural analysis. Accordingly, we have found that CA restores, at least in part, sensitivity to Tz in SKBR-3 Tz-resistant cell line.ConclusionsOur data demonstrate the cooperation between CA and Tz in inhibiting cell migration and survival of ERBB2+ BC cells that warrant further studies to establish if CA or CA derivatives may be useful in vivo in the treatment of ERBB2+ cancers.Electronic supplementary materialThe online version of this article (10.1186/s13046-017-0615-0) contains supplementary material, which is available to authorized users.

Anti‑proliferative and pro‑apoptotic effects of rosemary and constituent terpenoids in a model for the HER‑2‑enriched molecular subtype of clinical breast cancer

“…Furthermore, treatment of HER-2-expressing breast cancer cells with trastuzumab-emtansine (T-DM1) conjugate upregulates cyclin B1 expression in T-DM1-sensitive, but not resistant, phenotypes (29); thus, high levels of cyclin B1 in G 2 /M arrested cells raise the possibility that proteasome-mediated degradation of the G 2 -specific cyclin may be impaired resultant to treatment with CA and CSOL. Furthermore, CA has been documented to synergize the antitumor activity of trastuzumab in HER-2-positive breast cancer cells (30), and CSOL has been identified to function as a potent inhibitor of transcriptional activation of inducible COX-2 and of prostaglandin production in 184-B5/HER cells. The mechanisms for efficacy of CSOL in this model involve protein kinase C, ERK1/2, JNK and p38-associated MAPK pathways (15).…”

Carnosic acid potentiates the anticancer effect of temozolomide by inducing apoptosis and autophagy in glioma

“…In addition to its capacities to directly inhibit tumor progression, CA could synergistically augment the activity of some chemotherapeutic agents in several different types of cancer. CA enhanced trastuzumab inhibition of cell survival and cell migration and induced cell cycle arrest in ERBB2 + breast cancer [ 12 ]. CA inhibited cell proliferation and enhanced cell apoptosis by increasing intracellular ROS in hepatocellular carcinoma [ 9 ].…”

Subtype-specific risk models for accurately predicting the prognosis of breast cancer using differentially expressed autophagy-related genes

“…The ERBB2 signal is closely related to autophagy. The activation of the ERBB2 signaling pathway can induce autophagy in a variety of cancers [ 28 – 30 ]. Then, we analyzed three breast cancer subtypes and constructed models by Cox regression and lasso regression, subsequently.…”