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Octamer 4 small interfering RNA results in cancer stem cell-like cell apoptosis
Tingsong Hu1, Shanrong Liu, Deborah R Breiter
1Department of Medical Genetics, Second Military Medical University, Shanghai, China.
Abstract:
Octamer 4 (Oct4), a member of the POU family of transcription factors, plays a key role in the maintenance of pluripotency and proliferation potential of embryonic stem cells. Cancer stem cell-like cells (CSCLC) are reported to be a minor population in tumors or even in tumor cell lines which also express Oct4. The role of Oct4 in CSCLCs still remains to be defined. In our study, we show that, in vitro, almost all murine Lewis lung carcinoma 3LL cells and human breast cancer MCF7 cells express Oct4 at high levels. This expression of Oct4 is successfully reduced by small interfering RNA, which eventually results in cell apoptosis. The signal pathway Oct4/Tcl1/Akt1 has been observed to be involved in this event. The repression of Oct4 reduces Tcl1 expression and further down-regulates the level of p-Ser.473-Akt1. In vivo, only approximately 5% of tumor cells were detected to express Oct4 in established 3LL and MCF7 tumor models, respectively. Small interfering RNA against Oct4 successfully decreases the CSCLCs and markedly inhibits tumor growth. In summary, we show that Oct4 might maintain the survival of CSCLCs partly through Oct4/Tcl1/Akt1 by inhibiting apoptosis, which strongly indicates that targeting Oct4 may have important clinical applications in cancer therapy.
Insights
Targeting Octamer 4 (Oct4) may offer new cancer therapies. Reducing Oct4 levels in cancer stem cells inhibits tumor growth by triggering apoptosis via the Oct4/Tcl1/Akt1 pathway.
Area of Science:
- Molecular Biology
- Cancer Research
- Stem Cell Biology
Background:
- Octamer 4 (Oct4) is crucial for embryonic stem cell pluripotency.
- Cancer stem cell-like cells (CSCLCs) express Oct4, but its role in these cells is unclear.
- CSCLCs are implicated in tumor development and resistance to therapy.
Purpose of the Study:
- To investigate the role of Oct4 in cancer stem cell survival and proliferation.
- To explore the potential of targeting Oct4 for cancer therapy.
Main Methods:
- Utilized small interfering RNA (siRNA) to reduce Oct4 expression in vitro and in vivo.
- Analyzed the effects of Oct4 reduction on CSCLC apoptosis, proliferation, and tumor growth.
- Investigated the involvement of the Oct4/Tcl1/Akt1 signaling pathway.
Main Results:
- In vitro, Oct4 knockdown in Lewis lung carcinoma (3LL) and breast cancer (MCF7) cells induced apoptosis.
- Oct4 repression led to decreased Tcl1 expression and reduced phosphorylation of Akt1 (p-Ser.473-Akt1).
- In vivo, Oct4 siRNA significantly reduced CSCLCs and inhibited tumor growth in established 3LL and MCF7 models.
Conclusions:
- Oct4 promotes CSCLC survival, partly by inhibiting apoptosis through the Oct4/Tcl1/Akt1 pathway.
- Targeting Oct4 presents a promising therapeutic strategy for cancer treatment.
- Further research into Oct4 inhibition could lead to novel clinical applications in oncology.
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