The oncogenic role of PKCiota gene amplification and overexpression in Chinese non-small cell lung cancer

Abstract

BackgroundThe atypical protein kinase C isozyme iota (PKCiota) has been proposed as an oncogene based on its transformation property and amplification identified in Caucasian non-small cell lung cancer (NSCLC) patients. Because the geography difference of some genetic aberrance such as EGFR mutations between Caucasian and Asian NSCLC patients has been identified previously, it is important to know whether the PKCiota amplification also occurs in Asian NSCLC patients. MethodsThe PKCiota gene copy number changes and protein expression in Chinese patients samples were detected by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC), respectively. Logistic regression was used to assess the association of PKCiota expression with clinicopathological parameters. siRNA-mediated gene silencing was applied to demonstrate the role of PKCiota in promoting cell growth in PKCiota gene amplified and protein overexpressed cancer cells. ResultsThe result showed that PKCiota gene was amplified in 20.2% (24/119) of the tested primary tumor samples from Chinese NSCLC patients. Interestingly this gene amplification was highly enriched in squamous NSCLC patients (37.1%, 23/62). Further IHC analysis indicated that PKCiota protein was highly expressed (IHC score 2+ and 3+) in 91.6% (109/119) of Chinese NSCLC tumors. Moreover, the PKCiota gene amplification was also correlated with gender, subtype and distant metastasis. Knockdown of PKCiota gene in the PKCiota gene amplified and protein overexpressed cells led to significant growth inhibition. ConclusionTaken together, our data demonstrate that PKCiota is a potential oncogene and therapeutic target in Chinese NSCLC.