Apoptosis (programmed cell death) is an essential cellular defence mechanism. What is the relationship between the apoptosis and lung cancer?
Caspase-3 as Biomarker of Apoptosis Related to Lung Cancer
In cancer research, we can use the biomarkers to predict the induction of apoptosis. Consequently, this enables us to identify the biological signs that may indicate increased risk for the disease. During the time the cells undergoing apoptosis, the cytochrome c will be released from mitochondria to the cytoplasm and activate the caspase-3. Caspase-3 plays an important role in apoptotic pathway. It has been recognized as biomarkers of apoptosis. The cancer research shows that there is a significant correlation between the expression of caspase-3, survival and metastasis in 135 non-small cell lung carcinomas.
2 Principal Signalling Pathways in Apoptosis Related to Lung Cancer
i. Extrinsic Apoptosis Pathway
In the extrinsic apoptosis pathway, polymorphisms influencing the FASL-FAS interaction will affect the lung cancer predisposition. In cancer research, there are 2 promoter SNPs of FAS and FASL will cause the increased risks of lung cancer.
ii. Intrinsic Apoptosis Pathway
In the intrinsic apoptosis pathway, caspase-9 is the only gene that has been detected for a role in lung cancer development. According to Park et al. cancer study, they found that two caspase-9 promoter SNPs were related to the significantly altered lung cancer risk.
Bcl-2 Proteins as Anti-apoptotic Proteins Causing Lung Cancer
As we all know, apoptosis is a highly programmed pathway that regulated by many of genes. One of the famous genes in apoptosis is Bcl-2 family genes. Bcl-2 is a proto-oncogene that is known to promote cell survival. The Bcl-2 proteins act as anti-apoptotic proteins that regulate the apoptosis. These proteins inhibit the apoptotic cascade.
By doing the cancer research on Bcl-2 mRNA expression in some tissues, the Bcl-2 mRNA expression in lung cancer tissues was significantly increased. This over-expression of Bcl-2 has been recognized to be early event in carcinogenesis that allows the cells with DNA damage to escape from normal mechanisms of apoptosis. In contrast, the lack of Bcl-2 expression may reduce the cause the relatively late in the pathogenesis in lung cancer.
In conclusion, lung cancer is highly associated with the apoptosis especially for the cancer research on finding the treatment. The cancer research needs to go further so that we can manipulate the apoptotic pathway for lung cancer treatment.
(Reference: David S. Albert, Lisa M. Hess. Fundamental of Cancer Prevention, Second edition)
