Downregulating activated epidermal growth factor receptor has no effect on RBM5 expression

Area of Science:

• Oncology
• Molecular Biology
• Cancer Genetics

Background:

• The tumor suppressor gene RBM5 is regulated differently across lung cancer subtypes.
• RBM5 expression is reduced in non-small cell lung carcinomas (NSCLC) and deleted in small cell lung cancers.
• In lung adenocarcinomas, smoking is linked to KRAS mutations, while non-smokers show EGFR mutations, suggesting a link to RBM5 inhibition.

Purpose of the Study:

• To investigate the hypothesis that activating mutations in EGFR indirectly inhibit RBM5 in lung adenocarcinomas.
• To determine if EGFR activation and RBM5 expression are negatively correlated in lung adenocarcinoma.

Main Methods:

• EGFR expression was inhibited in the NCI-H1975 lung adenocarcinoma cell line using small interfering RNA.
• RBM5 expression was quantified at both RNA and protein levels using real-time quantitative PCR and Western blotting.

Main Results:

• Inhibition of EGFR expression did not result in any significant change in RBM5 expression.
• RBM5 expression remained unchanged at both the RNA and protein levels despite EGFR manipulation.

Conclusions:

• EGFR does not appear to directly regulate RBM5 expression in non-smoker associated lung adenocarcinomas.
• Alternative mechanisms likely control RBM5 expression or function in lung cancers that retain the RBM5 gene.