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Intratumoral injection of PKR shRNA expressing plasmid inhibits B16-F10 melanoma growth
Nayara Delgado André1, Viviane Aline Oliveira Silva2, Maria Angelica Ehara Watanabe3
1Federal University of São João del-Rei, 35501296 Divinópolis, MG, Brazil.
Abstract:
The RNA-dependent protein kinase (PKR) is a serine/threonine kinase that is involved in the regulation of important cell processes such as apoptosis, signal transduction, cell proliferation and differentiation. However, the role played by PKR in cancer remains controversial. RNA interference (RNAi) has currently become an important technique in understanding gene function. Previously, we showed that PKR shRNA downregulates PKR expression in B16-F10 melanoma cells and reduces the metastatic potential of these tumor cells. In the present study, we examined the effect of the intratumoral injection of PKR shRNA‑expressing plasmid on the growth of B16-F10 melanoma in mice. The results showed that this treatment significantly reduced tumor growth. Thus, these findings suggested that PKR acts as a tumor suppressor, a finding that is consistent with our previous study on the experimental model of metastasis. Moreover, the results suggested that this effect may be mediated by the transcription factor NF-κB. The present study confirmed the hypothesis that the direct administration of RNAi-based therapeutics in the target tumor is a promising approach for overcoming the obstacles of systemic delivery. The results also suggested that the intratumoral injection of PKR shRNA‑expressing vector is a novel therapeutic approach for human solid tumors such as cutaneous melanoma and breast cancer, since PKR is overexpressed in these tumors.
Insights
RNA-dependent protein kinase (PKR) acts as a tumor suppressor. Intratumoral injection of PKR shRNA effectively reduced melanoma tumor growth, suggesting a novel therapeutic strategy for cancers.
Area of Science:
- Molecular Biology
- Cancer Research
- Immunology
Background:
- RNA-dependent protein kinase (PKR) is a serine/threonine kinase regulating crucial cellular processes.
- The precise role of PKR in cancer development and progression remains debated.
- RNA interference (RNAi) is a valuable tool for elucidating gene function.
Purpose of the Study:
- To investigate the therapeutic potential of intratumoral PKR shRNA delivery in a murine melanoma model.
- To determine the effect of PKR downregulation on melanoma tumor growth.
- To explore the role of PKR as a tumor suppressor in melanoma.
Main Methods:
- Intratumoral injection of PKR shRNA-expressing plasmid into B16-F10 melanoma tumors in mice.
- Assessment of tumor growth following treatment.
- Analysis of potential involvement of the transcription factor NF-κB.
Main Results:
- Intratumoral administration of PKR shRNA significantly inhibited B16-F10 melanoma tumor growth.
- PKR downregulation demonstrated a tumor-suppressive effect, consistent with prior metastasis studies.
- Evidence suggests the transcription factor NF-κB may mediate the observed anti-tumor effects.
Conclusions:
- Direct intratumoral administration of RNAi-based therapeutics is a viable strategy for cancer treatment, circumventing systemic delivery challenges.
- Intratumoral PKR shRNA represents a promising novel therapeutic approach for solid tumors, including cutaneous melanoma and breast cancer, where PKR is often overexpressed.
