Transcriptome analysis of neratinib treated HER2 positive cancer model vs untreated cancer unravels the molecular mechanism of action of neratinib.

Human estrogen receptor positive cancer cells have mutations and make an excess of the HER2 protein and are far more aggressive than others cancers. Neratinib, an irreversible tyrosine kinase inhibitor is used to treat HER2 positive cancers. Neratinib targets HER2 and blocks its signal transduction resulting in inhibition of cell proliferation and induction of apoptosis without any information about the molecular mechanism involved. To understand the underlying molecular mechanism transcriptome analysis was carried out in normal vs cancer induced SWR/J nude mice. Cancer was induced in SWR/J nude mice with intraperitoneal injection of 5 x 10(6) SKBR3 cells for 14 days. Histopathology confirmed the induction of cancer in liver and kidney after the tumor size was at least 0.5 cm. Genome wide Mouse U133 Array was used to analyze the effect of neratinib treatment on cancer. Validation of expression was done by qPCR and ELISA. Microscopic examination revealed that neratinib treatment has potential effects on cancerous liver. Transcriptome expression profiling showed 1481 transcripts differentially expressed by neratinib treatment. Transcriptome Analysis Console (TAC) showed that 532 upregulated transcripts were exclusively belonging to cell cycle, inflammation, olfaction, oxidative stress, HER, and EGFR1 while 949 downregulated transcripts were involved in immunology, drug resistance such as histocompatibility, T cell receptors, and immunoglobulins. The differentially expressed genes were considered significant under the criteria of an adjusted p-value < 0.02 and log2 ratios >= 1.0 and/or log2 ratios <= -1.0 means two Fold change. qPCR assay and ELISA analysis was used to validate few genes involved in apoptosis and proliferation. This study provides new insights into the neratinib's mode of action by cyclin-dependent kinase inhibitor-3 and calcium-activated chloride channel 3 as markers for treatment progress. (C) 2020 King Saud University. Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).