Lapatinib In HER2-positive Breast Cancer Research Articles

Induction of EnR stress by Melatonin enhances the cytotoxic effect of Lapatinib in HER2-positive breast cancer.

Despite HER2-targeted cancer treatments have provided considerable clinical benefits, resistance to HER2-targeted agents will inevitably develop. Targeting non-oncogene vulnerabilities including endoplasmic reticulum (EnR) stress has emerged as an attractive alternative approach to improve the efficacy of existing targeted cancer therapies. In the current study, we find that Melatonin sensitizes HER2-positive breast cancer cells to the dual tyrosine kinase inhibitor Lapatinib in vitro. Mechanistically, Melatonin enhances the cytotoxic effects of Lapatinib through promoting excessive EnR stress-induced unfolded protein response (UPR) and ROS overaccumulation. Consistently, the antioxidant N-acetylcysteine remarkably reverses the effects of the drug combination on ROS production, DNA damage and cytotoxicity. Furthermore, Melatonin significantly enhances the anti-tumor effect of Lapatinib in an HCC1954 xenograft model. Meanwhile, Lapatinib resistant HER2-positive breast cancer cells (LapR) display lower basal expression levels of UPR genes and enhanced tolerance to EnR stress with attenuated response to Brefeldin A and Tunicamycin. Importantly, Melatonin also increases the sensitivity of HCC1954 LapR cells to Lapatinib. Together, our findings highlight the potential utility of Melatonin as an adjuvant in the treatment of primary or therapy resistant HER2-positive breast cancer via EnR stress-mediated mechanisms.

Survival, pathologic response, and genomics in CALGB 40601 (Alliance), a neoadjuvant Phase III trial of paclitaxel-trastuzumab with or without lapatinib in HER2-positive breast cancer

Survival, pathologic response, and genomics in CALGB 40601 (Alliance), a neoadjuvant Phase III trial of paclitaxel-trastuzumab with or without lapatinib in HER2-positive breast cancer

Development of acquired resistance to lapatinib may sensitise HER2-positive breast cancer cells to apoptosis induction by obatoclax and TRAIL

BackgroundLapatinib has clinical efficacy in the treatment of trastuzumab-refractory HER2-positive breast cancer. However, a significant proportion of patients develop progressive disease due to acquired resistance to the drug. Induction of apoptotic cell death is a key mechanism of action of lapatinib in HER2-positive breast cancer cells.MethodsWe examined alterations in regulation of the intrinsic and extrinsic apoptosis pathways in cell line models of acquired lapatinib resistance both in vitro and in patient samples from the NCT01485926 clinical trial, and investigated potential strategies to exploit alterations in apoptosis signalling to overcome lapatinib resistance in HER2-positive breast cancer.ResultsIn this study, we examined two cell lines models of acquired lapatinib resistance (SKBR3-L and HCC1954-L) and showed that lapatinib does not induce apoptosis in these cells. We identified alterations in members of the BCL-2 family of proteins, in particular MCL-1 and BAX, which may play a role in resistance to lapatinib. We tested the therapeutic inhibitor obatoclax, which targets MCL-1. Both SKBR3-L and HCC1954-L cells showed greater sensitivity to obatoclax-induced apoptosis than parental cells. Interestingly, we also found that the development of acquired resistance to lapatinib resulted in acquired sensitivity to TRAIL in SKBR3-L cells. Sensitivity to TRAIL in the SKBR3-L cells was associated with reduced phosphorylation of AKT, increased expression of FOXO3a and decreased expression of c-FLIP. In SKBR3-L cells, TRAIL treatment caused activation of caspase 8, caspase 9 and caspase 3/7. In a second resistant model, HCC1954-L cells, p-AKT levels were not decreased and these cells did not show enhanced sensitivity to TRAIL. Furthermore, combining obatoclax with TRAIL improved response in SKBR3-L cells but not in HCC1954-L cells.ConclusionsOur findings highlight the possibility of targeting altered apoptotic signalling to overcome acquired lapatinib resistance, and identify potential novel treatment strategies, with potential biomarkers, for HER2-positive breast cancer that is resistant to HER2 targeted therapies.

Yes1 signaling mediates the resistance to Trastuzumab/Lap atinib in breast cancer

BackgroundOverexpression of human epidermal growth factor receptor 2 (HER2) is observed in approximately 15–23% of breast cancers and these cancers are classified as HER2-positive breast cancer. Trastuzumab is the first-line targeted therapeutic drug for HER2-positive breast cancer and has improved patient overall survival. However, acquired resistance to trastuzumab is still a critical issue in breast cancer treatment. We previously established a trastuzumab-resistant breast cancer cell line (named as BT-474-R) from a trastuzumab-sensitive HER2-amplified cell line BT-474. Lapatinib is also a molecular-targeted drug for HER2-positive breast cancer, which acquired the resistance to trastuzumab. Acquired resistance to lapatinib is also an issue to be conquered.MethodsWe established trastuzumab/lapatinib-dual resistant cell line (named as BT-474-RL2) by additionally treating BT-474-R with lapatinib. We analyzed the mechanisms of resistance to trastuzumab and lapatinib. Besides, we analyzed the effect of the detected resistance mechanism in HER2-positive breast cancer patients.ResultsProto-oncogene tyrosine-protein kinase Yes1, which is one of the Src family members, was amplified, overexpressed and activated in BT-474-R and BT-474-RL2. Silencing of Yes1 by siRNA induced both BT-474-R and BT-474-RL2 to restore the sensitivity to trastuzumab and lapatinib. Pharmaceutical inhibition of Yes1 by the Src inhibitor dasatinib was also effective to restore the sensitivity to trastuzumab and lapatinib in the two resistant cell lines. Combination treatment with dasatinib and trastuzumab induced down-regulation of signaling molecules such as HER2 and Akt. Moreover, the combination treatments induced G1-phase cell-cycle arrest and apoptosis. Consistent with cell line data, high expression of Yes1 mRNA was correlated with worse prognosis in patients with HER2-positive breast cancer.ConclusionYes1 plays an important role in acquired resistance to trastuzumab and lapatinib in HER2-positive breast cancer. Our data suggest that pharmacological inhibition of Yes1 may be an effective strategy to overcome resistance to trastuzumab and lapatinib.

Immunoglobulin G fragment C receptor polymorphisms and efficacy of preoperative chemotherapy plus trastuzumab and lapatinib in HER2-positive breast cancer.

Lapatinib enhances antibody-dependent cell-mediated cytotoxicity (ADCC) activity of trastuzumab. FcγR polymorphisms have been associated with both ADCC and clinical activity of trastuzumab in HER2+ breast cancer (BC) patients (pts). We analyzed FcγRIIa-H131R and FcγRIIIa-V158F polymorphisms in the CHER-LOB trial population of HER2+ BCs treated with preoperative chemotherapy plus trastuzumab (arm A), lapatinib (arm B) or both (arm C). Genotyping was successfully performed in 73/121 (60%) pts. A significant improvement in pathological complete response (pCR) rate was observed for the combination arm C, but only in FcγRIIIa V allele carriers (C vs A, 67 vs 27%, P=0.043; C vs B, 67 vs 22%, P=0.012). An independent interaction between arm C and FcγRIIIa V allele was found for pCR (odds ratio=9.4; 95% confidence interval, 2.3-39.6; P=0.003). No significant associations were observed between pCR and FcγRIIa polymorphism, and between pre-treatment tumor-infiltrating lymphocytes and FcγR polymorphisms. Our study provides evidence for a FcγRIIIa V allele-restricted pCR benefit from neoadjuvant trastuzumab plus lapatinib in HER2+ BC.

Gene expression signatures in pre- and post-therapy (Rx) specimens from CALGB 40601 (Alliance), a neoadjuvant phase III trial of weekly paclitaxel and trastuzumab with or without lapatinib for HER2-positive breast cancer (BrCa).

506 Background: Response to chemotherapy and HER2-targeting varies by molecular subtype. In C40601, 305 patients (pts) with stage II-III HER2+ BrCa were randomized to receive 16 weeks of preoperati...

Clinical and translational results of CALGB 40601: A neoadjuvant phase III trial of weekly paclitaxel and trastuzumab with or without lapatinib for HER2-positive breast cancer.

500 Background: Recent trials in HER2-positive (HER2+) breast cancer (BrCa) demonstrate increased pathological complete response (pCR) using dual HER2-targeting in the neoadjuvant setting and increased progression-free survival in metastatic disease. CALGB 40601 aimed to further quantify the pCR rates of weekly paclitaxel (T) and trastuzumab (H) alone or combined HER2-blockade of H with the small molecule lapatinib (L), and to identify biomarkers of sensitivity to these HER2-targeted agents. Methods: Eligible patients had newly diagnosed, noninflammatory stage II-III HER2+ BrCa and were randomized to receive T (80mg/m2/week IV) + H (4mg/kg then 2mg/kg/week IV) alone (TH) or with the addition of L (750 mg/d PO) (THL) for 16 weeks preoperatively. A third arm, T + L (1500 mg/d) (TL), was closed early when negative efficacy and toxicity data emerged from preliminary analysis of ALTTO. After surgery, 4 cycles of adjuvant dose-dense AC and 1 year H was recommended. Tumors were biopsied for research before therapy; post-Rx samples of residual disease were requested. The primary endpoint was in-breast pCR rate; the study had 85% power to detect an increase from 30% (TH) to 50% (THL). Results: 305 patients were randomized (118 THL, 120 TH, 67 TL); 68% were clinical stage II and 59% hormone receptor-positive. Grade 3+ toxicity was higher among L-containing arms, including neutropenia (12% TL, 7% THL, 2% TH), rash (15% TL, 14% THL, 2% TH), and diarrhea (20% TL, 20% THL, 2% TH). Breast pCR rates with 95% confidence limits were: 51% (42-60%) THL, 40% (32-49%) TH, 32% (22-44%) TL. pCR rate in the TH arm was higher than previous studies, and was not significantly different from THL (p=0.11). We will present molecular subtype, sequence and gene copy number abnormalities in primary tumors and residual disease. Conclusions: pCR rate was higher with combined THL compared with standard TH but did not reach statistical significance. These results are qualitatively similar to other neoadjuvant studies in HER2+ BrCa, and contribute to estimates of pCR rates after these agents. Tissue-based studies may illuminate which patients benefit from HER2-targeting using these agents. Clinical trial information: NCT00770809.

Synergistic activity of ixabepilone plus other anticancer agents: preclinical and clinical evidence.

Ixabepilone demonstrates marked synergistic activity in combination with capecitabine, which served as the rationale for the evaluation of this combination in the clinic. Ixabepilone plus capecitabine is currently approved for patients with locally advanced or metastatic breast cancer (MBC) progressing after treatment with an anthracycline and a taxane; approval was based on the results of two phase III trials comparing the combination with capecitabine monotherapy. An array of preclinical studies in multiple solid tumor types show that ixabepilone demonstrates therapeutic synergy with targeted therapies including trastuzumab, bevacizumab, brivanib, and cetuximab; with immune-modulating agents such as anti-CTLA-4 antibody; and with other chemotherapy drugs such as irinotecan and epirubicin. Notably, experiments in several xenograft models show that ixabepilone provides greater antitumor synergism when combined with bevacizumab than either paclitaxel or nab-paclitaxel combined with bevacizumab. These preclinical findings provide a foundation for ongoing phase II clinical trials using ixabepilone in combination with trastuzumab or lapatinib in HER2-positive breast cancer; with bevacizumab in breast cancer, endometrial cancer, renal cancer, and non-small cell lung cancer (NSCLC); with cetuximab in breast cancer, NSCLC, and pancreatic cancer; and with brivanib, dasatinib, sorafinib, sunitinib, or vorinostat in MBC. Preliminary results from several of these trials suggest that ixabepilone-based combinations have promising anticancer activity.

The emerging role of Lapatinib in HER2-positive breast cancer

In breast cancer, overexpression of HER2 is associated with an aggressive tumor phenotype and poor prognosis. Lapatinib has demonstrated benefit in combination with capecitabine in patients with HER2-positive locally advanced and metastatic breast cancer that has progressed after prior treatment with an anthracycline, a taxane, and trastuzumab. It has also demonstrated benefit with paclitaxel in patients with metastatic disease not previously treated with chemotherapy. This review discusses results from clinical trials suggesting an advantage with the use of lapatinib with other treatment modalities in the setting of metastatic and locally advanced disease.