Preferential expression of c-kit protooncogene transcripts in small cell lung cancer
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1First Department of Internal Medicine, Nagoya University School of Medicine, Japan.
Abstract:
As an initial step to understand rapid growth of small cell lung cancer (SCLC), a complementary DNA library prepared from a SCLC cell line was screened with viral oncogene probes encoding protein-tyrosine kinases, which are known to play an important role in regulation of cell growth. Fifteen clones hybridizing with v-fms probe were isolated, and, by partial sequence analysis, four of them were identified to be c-kit protooncogenes. Northern blot study demonstrated that most of the SCLC tumors and cell lines expressed c-kit transcripts, while non-SCLC tumors and cell lines did not. Neither amplification nor rearrangement of the c-kit gene was demonstrated in SCLC cell lines by Southern blot analysis, however. Our results suggested that c-kit expression in SCLC reflects the unique biological nature of the tumor cells different from non-SCLC and further suggested that the c-kit product may participate in autocrine or paracrine stimulation of SCLC growth.
Insights
Small cell lung cancer (SCLC) cells express c-kit protooncogenes, unlike other lung cancers. This suggests c-kit may drive SCLC growth through autocrine or paracrine signaling pathways.
Area of Science:
- Molecular Biology
- Oncology
- Cancer Research
Background:
- Protein-tyrosine kinases are crucial regulators of cell growth.
- Understanding the molecular basis of small cell lung cancer (SCLC) rapid growth is essential.
Purpose of the Study:
- To investigate the role of protein-tyrosine kinases in SCLC growth.
- To identify specific genes involved in SCLC proliferation.
Main Methods:
- Screening of a complementary DNA library from SCLC cells using viral oncogene probes.
- Partial sequence analysis to identify isolated clones.
- Northern blot analysis to assess gene expression in SCLC and non-SCLC tumors and cell lines.
- Southern blot analysis to detect gene amplification or rearrangement.
Main Results:
- Four c-kit protooncogenes were identified from fifteen clones hybridized with the v-fms probe.
- Most SCLC tumors and cell lines expressed c-kit transcripts.
- Non-SCLC tumors and cell lines did not express c-kit transcripts.
- No amplification or rearrangement of the c-kit gene was found in SCLC cell lines.
Conclusions:
- c-kit expression is a distinguishing feature of SCLC, differentiating it from non-SCLC.
- The c-kit product may be involved in autocrine or paracrine stimulation contributing to SCLC growth.