Apoptosis-prone phenotype of human colon carcinoma cells with a high level amplification of the c-myc gene

Maddalena Donzelli, Rosa Bernardi, Claudia Negri, Ennio Prosperi, Laura Padovan, Christian Lavialle, Olivier Brison, A. Ivana Scovassi

Research output: Contribution to journalArticlepeer-review

Abstract

Although apoptosis can be induced by the enforced expression of exogenously introduced c-myc genes, it is not clear whether overexpression resulting from the amplification of the resident c-myc gene in tumor cells is sufficient to induce apoptosis. We have investigated the relationship between c-myc gene amplification and the propensity of tumor cells to undergo apoptosis, using the SW613-12A1 and SW613-B3 cell lines, which are representatives, respectively, of tumorigenic and non-tumorigenic clones isolated from the SW613-S human colon carcinoma cell line. Tumorigenic clones are characterized by a high level of amplification and expression of the c-myc gene, whereas cells of non-tumorigenic clones have a small number of copies and a lower level of expression of this gene. Analysis of c-myc mRNA level in cells cultured under low serum conditions indicated that the expression of the gene is tightly regulated by serum growth factors in non-tumorigenic B3 cells, whereas it is poorly regulated in tumorigenic 12A1 cells, the level of mRNAs remaining relatively high in serum-starved 12A1 cells. Under these conditions, 12A1 cells showed clear evidence of apoptosis, whereas B3 cells were completely refractory to the induction of apoptosis. Moreover, the study of cell lines derived from non-tumorigenic apoptosis-resistant clones following the introduction by transfection of exogenous c-myc gene copies showed that they have acquired an apoptosis-prone phenotype. Altogether, our results strongly suggest that deregulated c-myc expression due to high-level amplification confers an apoptosis-prone phenotype to tumor cells. The possible consequences of these observations for cancer therapy are discussed.

Original languageEnglish
Pages (from-to)439-448
Number of pages10
JournalOncogene
Volume18
Issue number2
DOIs
Publication statusPublished - Jan 14 1999

Keywords

  • Amplification
  • Apoptosis
  • c-myc
  • Human colon carcinoma cells
  • PARP proteolysis
  • Serum starvation

ASJC Scopus subject areas

  • Molecular Biology
  • Cancer Research
  • Genetics

Fingerprint Dive into the research topics of 'Apoptosis-prone phenotype of human colon carcinoma cells with a high level amplification of the c-myc gene'. Together they form a unique fingerprint.

Cite this