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A vasoactive intestinal peptide receptor analog alters the expression of homeobox genes
Ruth A Steingart1, Eitan Heldenberg, Albert Pinhasov
1Department of Clinical Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Israel.
Abstract:
A lipophilic analog of vasoactive intestinal peptide (VIP), stearyl-Nle(17)-neurotensin(6-11)VIP(7-28) (SNH), that inhibited lung cancer growth, has been previously described. The mechanism of SNH inhibition of cancer growth is still being elucidated. The present study examined the effects of SNH on homeobox genes in the colon cancer cell line HT 29 that expresses VIP receptors. Homeobox genes contain a characteristic DNA sequence, coding for a stretch of 61 amino acid homeodomain that binds specific DNA motifs. While the HOX gene family contains a single homeodomain, the POU gene family contains an additional DNA binding homeodomain. HT 29 cells were incubated with SNH; RNA was extracted and subjected to reverse-transcription-polymerase chain reaction (RT-PCR) with primers that matched the conserved area of the various HOX or POU genes. The PCR products that were altered by SNH treatment were sequenced. Three candidate SNH-responsive genes, the HOX A4, the HOX B5 and the PUO V transcription factor I (Oct-3) were identified. Semi-quantitative RT-PCR with specific primers confirmed the increase in HOX A4 and the decrease in Oct-3 expression levels following SNH treatment. Thus, the HOX A4 and the Oct-3 homeobox genes may partially mediate SNH activity on cancer cells.
Insights
Stearyl-Nle(17)-neurotensin(6-11)VIP(7-28) (SNH) impacts homeobox gene expression in colon cancer cells. HOX A4 and Oct-3 (POU V transcription factor I) levels were altered by SNH, suggesting a role in its anti-cancer effects.
Area of Science:
- Molecular Biology
- Cancer Research
- Genetics
Background:
- Vasoactive intestinal peptide (VIP) analogs, like SNH, show potential in inhibiting cancer growth.
- The precise mechanisms by which SNH exerts its anti-cancer effects are not fully understood.
- Homeobox genes play crucial roles in cellular development and are implicated in various cancers.
Purpose of the Study:
- To investigate the impact of SNH on homeobox gene expression in the HT-29 colon cancer cell line.
- To identify specific homeobox genes that are modulated by SNH treatment.
- To elucidate the potential role of these genes in mediating SNH's anti-cancer activity.
Main Methods:
- Incubation of HT-29 cells with SNH.
- RNA extraction followed by reverse-transcription-polymerase chain reaction (RT-PCR) using primers for HOX and POU genes.
- Sequencing of SNH-altered PCR products to identify responsive genes.
- Semi-quantitative RT-PCR to confirm expression level changes.
Main Results:
- Three candidate SNH-responsive homeobox genes were identified: HOX A4, HOX B5, and Oct-3 (POU V transcription factor I).
- SNH treatment led to an observed increase in HOX A4 expression.
- SNH treatment resulted in a decrease in Oct-3 expression levels.
Conclusions:
- HOX A4 and Oct-3 are identified as potential mediators of SNH's effects on colon cancer cells.
- These findings contribute to understanding the molecular mechanisms underlying SNH's anti-cancer properties.
- Further research into HOX A4 and Oct-3 modulation could offer new therapeutic strategies for colon cancer.