Lapatinib for the treatment of breast cancer in the People's Republic of China

Aneuploidy Rate and Stemness in Low-Level Mosaic Human Embryonic Stem Cells in the Presence/Absence of Bortezomib, Paclitaxel, and Lapatinib

Human embryonic stem cells (hESCs) are predisposed to aneuploidy through continual passages. Some reports indicate more sensitivity of aneuploid hESCs cells to anticancer drugs. The present study was designed to investigate the cytotoxicity of three anticancer drugs (including bortezomib, paclitaxel, and lapatinib) and their effect on aneuploidy rate in hESCs. To create a low-level mosaic cell line, normal hESCs (80%) and trisomic hESCs for chromosomes 12 and 17 (20%) were mixed. The effect of the 3 mentioned anticancer drugs on the chromosomal status was assessed by metaphase spread analysis after selection of the nontoxic conditions. Expression of pluripotency genes was analyzed, and an alkaline phosphatase test was performed to assess pluripotency preservation. Our data showed that treatment with bortezomib, paclitaxel, and lapatinib was nontoxic at 0.01, 0.01, and 0.2 μM concentrations, respectively. Alkaline phosphatase and pluripotency gene expression analyses revealed maintenance of pluripotency following treatment with above-noted nontoxic concentrations. Aneuploid cells were dominant in treated and control groups with a minimum abundance of 70%, with no significant differences between groups. Drug treatments had no negative effect on pluripotency. Insensitivity of aneuploid cells in treatment groups could be related to the specific characteristics of each cell line in response to the drug and the proliferative superiority of cells with trisomies 12 and 17.

Inhibition of the Wnt Signalling Pathway: An Avenue to Control Breast Cancer Aggressiveness

Breast cancer (BC) is the most common tumour in women. Although the introduction of novel therapeutic approaches in clinical practice has dramatically improved the clinical outcome of BC patients, this malignant disease remains the second leading cause of cancer-related death worldwide. The wingless/integrated (Wnt) signalling pathway represents a crucial molecular node relevantly implicated in the regulation of normal somatic stem cells as well as cancer stem cell (CSC) traits and the epithelial-mesenchymal transition cell program. Accordingly, Wnt signalling is heavily dysregulated in BC, and the altered expression of different Wnt genes is significantly associated with cancer-related aggressive behaviours. For all these reasons, Wnt signalling represents a promising therapeutic target currently under clinical investigation to achieve cancer eradication by eliminating CSCs, considered by most to be responsible for tumour initiation, relapse, and drug resistance. In this review, we summarized the current knowledge on the Wnt signalling pathway in BC and have presented evidence implicating the suitability of Wnt targeting in an attempt to improve the outcome of patients without affecting the normal somatic stem cell population.

In vitro assessment of the photo(geno)toxicity associated with Lapatinib, a Tyrosine Kinase inhibitor

The epidermal growth factor receptors EGFR and HER2 are the main targets for tyrosine kinase inhibitors (TKIs). The quinazoline derivative lapatinib (LAP) is used since 2007 as dual TKI in the treatment of metastatic breast cancer and currently, it is used as an oral anticancer drug for the treatment of solid tumors such as breast and lung cancer. Although hepatotoxicity is its main side effect, it makes sense to investigate the ability of LAP to induce photosensitivity reactions bearing in mind that BRAF (serine/threonine-protein kinase B-Raf) inhibitors display a considerable phototoxic potential and that afloqualone, a quinazoline-marketed drug, causes photodermatosis. Metabolic bioactivation of LAP by CYP3A4 and CYP3A5 leads to chemically reactive N-dealkylated (N-LAP) and O-dealkylated (O-LAP) derivatives. In this context, the aim of the present work is to explore whether LAP and its N- and O-dealkylated metabolites can induce photosensitivity disorders by evaluating their photo(geno)toxicity through in vitro studies, including cell viability as well as photosensitized protein and DNA damage. As a matter of fact, our work has demonstrated that not only LAP, but also its metabolite N-LAP have a clear photosensitizing potential. They are both phototoxic and photogenotoxic to cells, as revealed by the 3T3 NRU assay and the comet assay, respectively. By contrast, the O-LAP does not display relevant photobiological properties. Remarkably, the parent drug LAP shows the highest activity in membrane phototoxicity and protein oxidation, whereas N-LAP is associated with the highest photogenotoxicity, through oxidation of purine bases, as revealed by detection of 8-Oxo-dG.

BioPATH: A Biomarker Study in Asian Patients with HER2+ Advanced Breast Cancer Treated with Lapatinib and Other Anti-HER2 Therapy

PURPOSE

BioPATH is a non-interventional study evaluating the relationship of molecular biomarkers (PTEN deletion/downregulation, PIK3CA mutation, truncated HER2 receptor [p95HER2], and tumor HER2 mRNA levels) to treatment responses in Asian patients with HER2+ advanced breast cancer treated with lapatinib and other HER2-targeted agents.

Materials and Methods

Female Asian HER2+ breast cancer patients (n=154) who were candidates for lapatinib-based treatment following metastasis and having an available primary tumor biopsy specimen were included. The primary endpoint was progression-free survival (PFS). Secondary endpoints were response rate, overall survival on lapatinib, correlation between biomarker status and PFS for any previous trastuzumab-based treatment, and conversion/conservation rates of the biomarker status between tissue samples collected at primary diagnosis and at recurrence/metastasis. Potential relationships between tumor mRNA levels of HER2 and response to lapatinib-based therapy were also explored.

RESULTS

p95HER2, PTEN deletion/downregulation, and PIK3CA mutation did not demonstrate any significant co-occurrence pattern and were not predictive of clinical outcomes on either lapatinib-based treatment or any previous trastuzumab-based therapy in the metastatic setting. Proportions of tumors positive for p95HER2 expression, PIK3CA mutation, and PTEN deletion/down-regulation at primary diagnosis were 32%, 31.2%, and 56.2%, respectively. Despite limited availability of paired samples, biomarker status patterns were conserved in most samples. HER2 mRNA levels were not predictive of PFS on lapatinib.

CONCLUSION

The prevalence of p95HER2 expression, PIK3CA mutation, and PTEN deletion/downregulation at primary diagnosis were similar to previous reports. Importantly, no difference was observed in clinical outcome based on the status of these biomarkers, consistent with reports from other studies.

The addition of calcitriol or its synthetic analog EB1089 to lapatinib and neratinib treatment inhibits cell growth and promotes apoptosis in breast cancer cells

In breast cancer the use of small molecule inhibitors of tyrosine kinase activity of the ERBB family members improves survival thus represents a valuable therapeutic strategy. The addition of calcitriol, the most active metabolite of vitamin D, or some of its analogs, to conventional anticancer drugs, including tyrosine kinase inhibitors (TKIs), has shown an increased effect on the inhibition of cancer cell growth. In this work, we have evaluated the effects and the mechanism of action of the combination of calcitriol or its analog EB1089 with lapatinib or neratinib on EGFR and/or HER2 positive breast cancer cell lines. Lapatinib, neratinib, calcitriol and EB1089 inhibited breast cancer cell proliferation in a concentration-dependent manner. Addition of calcitriol or EB1089 to TKIs treatment induced more effective inhibiting effect on cell growth and AKT and MAPK phosphorylation than all compounds alone. The combined treatments incremented also the expression of active caspase 3 and induced cell death in two and three-dimensional cell culture and significantly inhibited anchorage-independent colony formation. Our results suggest that the addition of calcitriol or its analog EB1089 to conventional targeted therapies, including lapatinib or neratinib might be of benefit to patients with breast cancer, particularly those with an EGFR and/or HER2 positive phenotype.

Synthesis of Novel Hybrids of Quinazoline and Artemisinin with High Activities against Plasmodium falciparum, Human Cytomegalovirus, and Leukemia Cells

Many quinazoline derivatives have been synthesized over the last few decades with great pharmacological potential, such as antimalarial, anti-inflammatory, antimicrobial, anticancer, and antiviral. But so far, no quinazoline-artemisinin hybrids have been reported in the literature. In the present study, five novel quinazoline-artemisinin hybrids were synthesized and evaluated for their in vitro biological activity against malarial parasites (Plasmodium falciparum 3D7), leukemia cells (CCRF-CEM and CEM/ADR5000), and human cytomegalovirus. Remarkably, hybrid 9 (EC₅₀ = 1.4 nM), the most active antimalarial compound of this study, was not only more potent than artesunic acid (EC₅₀ = 9.7 nM) but at the same time more active than the clinically used drugs dihydroartemisinin (EC₅₀ = 2.4 nM) and chloroquine (EC₅₀ = 9.8 nM). Furthermore, hybrids 9 and 10 were the most potent compounds with regard to anticytomegaloviral activity (EC₅₀ = 0.15-0.21 μM). They were able to outperform ganciclovir (EC₅₀ = 2.6 μM), which is the relevant standard drug of antiviral therapy, by a factor of 12-17. Moreover, we identified a new highly active quinazoline derivative, compound 14, that is most effective in suppressing cytomegalovirus replication with an EC₅₀ value in the nanomolar range (EC₅₀ = 50 nM). In addition, hybrid 9 exhibited an antileukemia effect similar to that of artesunic acid, with EC₅₀ values in the low micromolar range, and was 45 times more active toward the multidrug-resistant CEM/ADR5000 cells (EC₅₀ = 0.5 μM) than the standard drug doxorubicin.

Synthesis and cytotoxic activities of novel 4-methoxy-substituted and 5-methyl-substituted (3'S,4'S)-(-)-cis-khellactone derivatives that induce apoptosis via the intrinsic pathway

This study deals with the design and synthesis of a series of novel 4-methoxy-substituted and 5-methyl-substituted (3'S,4'S)-(-)-cis-khellactones. The newly synthesized compounds were characterized by 1H nuclear magnetic resonance (NMR), 13C-NMR, mass spectrometry, and elemental analysis. All the derivatives were subjected to in vitro cytotoxicity screening against HEPG-2 (human liver carcinoma), SGC-7901 (human gastric carcinoma), and LS174T (human colon carcinoma), by using the MTT assay. The results revealed that several of the 4-methoxy-substituted compounds exhibited potent cytotoxicity. Among these, compound 12e showed the highest activity against cancer cells which 50% inhibitory concentration (IC50) values were in the range of 6.1-9.2 μM with low toxicity on normal human hepatocyte. Preliminary investigation of possible mechanisms of action of compound 12e against HEPG-2 cells indicated possible induction of apoptosis, as determined by morphological observations and Annexin V/propidium iodide (PI) double staining, in addition to apparent dissipation of mitochondrial membrane potential (MMP), as measured by 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl-imidacarbocyanine iodide (JC-1) staining in combination with the activation of caspase-9 and caspase-3 by Western blot analysis. Overall, the data suggest that compound 12e may be a promising potential anti-cancer agent that could act primarily by inducing apoptosis through the mitochondria-mediated intrinsic pathway in human hepatoma cells.

Lapatinib promotes the incidence of hepatotoxicity by increasing chemotherapeutic agent accumulation in hepatocytes

Lapatinib has been used in combination with capecitabine or paclitaxel to treat patients with progressive HER2-overexpressing metastatic breast cancer (MBC). Unfortunately, an increased incidence of hepatotoxicity had been reported in the combinational therapy. The aim of this study was to investigate the potential mechanisms of this combinational therapy. We found that the patients receiving lapatinib and paclitaxel treatment showed a higher incidence of hepatobiliary system disorders than those receiving paclitaxel alone. Lapatinib was shown to increase the accumulation of doxorubicin in ABCB1-overexpressing hepatocellular cancer cells and normal liver tissues without altering the protein level of ABCB1. Pharmacokinetic studies revealed that lapatinib could increase the systematic exposure of paclitaxel and doxorubicin. Moreover, the in vivo experiments showed that the levels of alanine aminotransferase and serious hepatocyte injury in the group of lapatinib plus chemotherapeutic agent were significantly higher than those in the group of single chemotherapeutic agent such as paclitaxel or doxorubicin. Our study thus revealed for the first time that the higher incidence of hepatotoxicity during this combinational treatment was due to the increased drug accumulation in hepatocytes mediated by the inhibition of ABCB1 by lapatinib. Appropriate dose adjustment may be needed to optimize the combination therapy.