Generation and Characterization of Trastuzumab/Pertuzumab-Resistant HER2-Positive Breast Cancer Cell Lines.

The combination of trastuzumab and pertuzumab as first-line therapy in patients with HER2-positive breast cancer has shown significant clinical benefits compared to trastuzumab alone. However, despite initial therapeutic success, most patients eventually progress, and tumors develop acquired resistance and invariably relapse. Therefore, there is an urgent need to improve our understanding of the mechanisms governing resistance in order to develop targeted therapeutic strategies with improved efficacy. We generated four novel HER2-positive cell lines via prolonged exposure to trastuzumab and pertuzumab and determined their resistance rates. Long-term resistance was confirmed by a significant increase in the colony-forming capacity of the derived cells. We authenticated the molecular identity of the new lines via both immunohistochemistry for the clinical phenotype and molecular profiling of point mutations. HER2 overexpression was confirmed in all resistant cell lines, and acquisition of resistance to trastuzumab and pertuzumab did not translate into differences in ER, PR, and HER2 receptor expression. In contrast, changes in the expression and activity of other HER family members, particularly HER4, were observed. In the same vein, analyses of the receptor and effector kinase status of different cellular pathways revealed that the MAPK pathway may be involved in the acquisition of resistance to trastuzumab and pertuzumab. Finally, proteomic analysis confirmed a significant change in the abundance patterns of more than 600 proteins with implications in key biological processes, such as ribosome formation, mitochondrial activity, and metabolism, which could be relevant mechanisms in the generation of resistance in HER2-positive breast cancer. We concluded that these resistant BCCLs may be a valuable tool to better understand the mechanisms of acquisition of resistance to trastuzumab and pertuzumab-based anti-HER2 therapy.

Molecular Targeted Therapy in Oncology Focusing on DNA Repair Mechanisms.

DNA repair mechanisms are essential for maintaining cellular homeostasis. Malfunction of these repair mechanisms leads to cellular DNA mutations, carcinogenic transformation, and cell death. These same defects also create vulnerabilities that are relatively specific to cancer cells, and which could potentially be exploited to increase the therapeutic index of anticancer treatments and thereby improve patient outcomes. The targeted therapy based on inhibiting the DNA damage response (DDR) opens a new therapeutic landscape for patients with deficient DDR. Currently there are two DNA repair mechanisms that are used as targets for molecular therapies: Mitsmach Repair (MMR) and Homologous Recombination Repair (HRR). These molecular targets allow for immunotherapy treatments based on "checkpoint inhibitors" (ICIs) drugs and "PARP inhibitor" (PARPi) drugs in different solid tumors. In this review we will describe the state of the art of this interesting mechanism and explain the options for treatment based on these alterations. Moreover, many clinical trials are currently underway exploring better treatment options for dMMR and HRD patients with different solid tumours.

Early detection of anthracycline- and trastuzumab-induced cardiotoxicity: value and optimal timing of serum biomarkers and echocardiographic parameters.

AIMS: To evaluate echocardiographic and biomarker changes during chemotherapy, assess their ability to early detect and predict cardiotoxicity and to define the best time for their evaluation. METHODS AND RESULTS: Seventy-two women with breast cancer (52 ± 9.8 years) treated with anthracyclines (26 also with trastuzumab), were evaluated for 14 months (6 echocardiograms/12 laboratory tests). We analysed: high-sensitivity cardiac troponin T, NT-proBNP, global longitudinal strain (GLS), left ventricle end-systolic volume (LVESV), left ventricle end-diastolic volume (LVEDV), and left ventricular ejection fraction (LVEF). Cardiotoxicity was defined as a reduction in LVEF>10% compared with baseline with LVEF<53%. High-sensitivity troponin T levels rose gradually reaching a maximum peak at 96 ± 13 days after starting chemotherapy (P < 0.001) and 62.5% of patients presented increased values during treatment. NT-proBNP augmented after each anthracycline cycle (mean pre-cycle levels of 72 ± 68 pg/mL and post-cycle levels of 260 ± 187 pg/mL; P < 0.0001). Cardiotoxicity was detected in 9.7% of patients (mean onset at 5.2 months). In the group with cardiotoxicity, the LVESV was higher compared with those without cardiotoxicity (40 mL vs. 29.5 mL; P = 0.045) at 1 month post-anthracycline treatment and the decline in GLS was more pronounced (-17.6% vs. -21.4%; P = 0.03). Trastuzumab did not alter serum biomarkers, but it was associated with an increase in LVESV and LVEDV (P < 0.05). While baseline LVEF was an independent predictor of later cardiotoxicity (P = 0.039), LVESV and GLS resulted to be early detectors of cardiotoxicity [odds ratio = 1.12 (1.02-1.24), odds ratio = 0.66 (0.44-0.92), P < 0.05] at 1 month post-anthracycline treatment. Neither high-sensitivity troponin T nor NT-proBNP was capable of predicting subsequent cardiotoxicity. CONCLUSIONS: One month after completion of anthracycline treatment is the optimal time to detect cardiotoxicity by means of imaging parameters (LVESV and GSL) and to determine maximal troponin rise. Baseline LVEF was a predictor of later cardiotoxicity. Trastuzumab therapy does not affect troponin values hence imaging techniques are recommended to detect trastuzumab-induced cardiotoxicity.

Chemotherapy for cholangiocarcinoma: An update.

Cholangiocarcinomas (bile duct cancers) are a heterogeneous group of malignancies arising from the epithelial cells of the intrahepatic, perihilar and extrahepatic bile ducts. Patients diagnosed with cholangiocarcinoma must be evaluated by a multidisciplinary team and be treated with individualized management. First of all, it is very important to define the potential resectability of the tumor because surgery is the main therapeutic option for these patients. Overall, cholangiocarcinomas have a very poor prognosis. The 5-year survival rate is 5%-10%. In cases with a potentially curative surgery, 5-year survival rates of 25%-30% are reported. Therefore, it is necessary to increase the cure rate from surgery, exploring the survival benefit of any adjuvant strategy. It is difficult to clarify the role of adjuvant treatment in localized and locally advanced cholangiocarcinomas. There are limited data and the role of adjuvant chemotherapy/chemoradiation in patients with resected biliary tract cancer is poorly defined. The most relevant studies in the adjuvant setting are one from Japan, the well known ESPAC-3 and BILCAP from the United Kingdom and a meta-analysis. We show the results of these trials. According to medical oncology guidelines, postoperative adjuvant therapy is widely recommended for all patients with intrahepatic or extrahepatic cholangiocarcinoma who have microscopically positive resection margins, as well as for those with a complete resection but node-positive disease. Clinical trials are ongoing. The locally advanced cholangiocarcinoma setting includes a heterogeneous mix of patients: (1) patients who have had surgery but with macroscopic residual disease; (2) patients with locally recurrent disease after potentially curative treatment; and (3) patients with locally unresectable disease at presentation. In these patients, surgery is not an option and chemoradiation therapy can prolong overall survival and provide control of symptoms due to local tumor effects. Nowadays, no neoadjuvant therapy can be considered a standard approach for the treatment of patients with cholangiocarcinoma. There are promising results and randomized trials are needed in patients with a metastatic cholangiocarcinoma. In systemic therapy, no single drug or combination has consistently increased median survival beyond the expected 8-12 mo. It is always recommended that patients enrol in clinical trials. Clinical trials have shown that the more standard chemotherapy for a first line regimen of gemcitabine plus cisplatin (or oxaliplatin as a potentially better tolerated agent) is superior to gemcitabine alone. Leucovorin-modulated 5-fluorouracil, capecitabine monotherapy or single agent gemcitabine are reasonable options for patients with a borderline performance status. After progression in patients with an adequate performance status, active regimens that could be considered include gemcitabine plus capecitabine, or erlotinib plus bevacizumab, for second line treatment.

HER2 and hormone receptor-positive breast cancer--blocking the right target.

HER2-positive tumors have a worse prognosis than HER2-negative cancers. Although the standard treatment for HER2-positive metastatic breast cancer is chemotherapy and trastuzumab, the combination of aromatase inhibitors with anti-HER2 therapies has become an available strategy in patients with HER2-positive and hormone receptor-positive tumors. However, although this new treatment option is more effective than hormone therapy alone, it has not been compared with the standard chemotherapy and trastuzumab-based regimens. In fact, the activity observed in randomized clinical trials with chemotherapy and anti-HER2 therapies seems to be higher than that observed with aromatase inhibitors and trastuzumab-based or lapatinib-based therapies. In this article, we highlight the importance of considering chemotherapy and anti-HER2 therapy as the standard of care in HER2-positive and hormone receptor-positive tumors.