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Therapeutic targeting of polo-like kinase 1 using RNA-interfering nanoparticles (iNOPs) for the treatment of non-small cell lung cancer.

McCarroll JA, Dwarte T, Baigude H, Dang J, Yang L, Erlich RB, Kimpton K, Teo J, Sagnella SM, Akerfeldt MC, Liu J, Phillips PA, Rana TM, Kavallaris M - Oncotarget (2015)

Bottom Line: Polo-like kinase 1 (PLK1) is a serine-threonine protein kinase which is overexpressed in cancer cells, and plays a major role in regulating tumor growth.Notably, iNOP-7 delivered siRNA to orthotopic lung tumors in mice, and administration of iNOP-7-PLK1 siRNA reduced lung tumor burden.These novel data show that iNOP-7 can deliver siRNA against PLK1 to NSCLC cells, and decrease cell proliferation both in vitro and in vivo. iNOP-7-PLK1 siRNA may provide a novel therapeutic strategy for the treatment of NSCLC as well as other cancers which aberrantly express this gene.

View Article: PubMed Central - PubMed

Affiliation: Children's Cancer Institute, Lowy Cancer Research Centre, Randwick, UNSW Australia (UNSW), NSW, Australia.

ABSTRACT
Non-small cell lung cancer (NSCLC) remains the most common cause of cancer death worldwide due its resistance to chemotherapy and aggressive tumor growth. Polo-like kinase 1 (PLK1) is a serine-threonine protein kinase which is overexpressed in cancer cells, and plays a major role in regulating tumor growth. A number of PLK1 inhibitors are in clinical trial; however, poor tumor bioavailability and off-target effects limit their efficacy. Short-interfering-RNA (siRNA) holds promise as a class of therapeutics, which can selectively silence disease-causing genes. However, siRNA cannot enter cells without a delivery vehicle. Herein, we investigated whether RNAi-interfering nanoparticles could deliver siRNA to NSCLC cells and silence PLK1 expression in vitro and in vivo. iNOP-7 was non-toxic, and delivered siRNA with high efficiency to NSCLC cells. iNOP-7-PLK1 siRNA silenced PLK1 expression and reduced NSCLC growth in vitro. Notably, iNOP-7 delivered siRNA to orthotopic lung tumors in mice, and administration of iNOP-7-PLK1 siRNA reduced lung tumor burden. These novel data show that iNOP-7 can deliver siRNA against PLK1 to NSCLC cells, and decrease cell proliferation both in vitro and in vivo. iNOP-7-PLK1 siRNA may provide a novel therapeutic strategy for the treatment of NSCLC as well as other cancers which aberrantly express this gene.

No MeSH data available.


Related in: MedlinePlus

Effect of PLK1 knockdown using siRNA on NSCLC cell death and cell cycle progression(A & B) Representative flow cytometry plots of annexin V staining in NSCLC cells (H1299, H460) and a graph showing an increase in the percentage of cells which stained positive with annexin V, 72h post-transfection with PLK1 siRNA (100 nM) complexed to lipofectamine 2000 (L2K). Cells treated with non-functional (Ctrl) siRNA served as controls. No difference in annexin V staining was observed in normal human lung fibroblasts (MRC-5), 72h post-transfection with PLK1 siRNA complexed to L2K when compared to controls (Ctrl siRNA), n = 3; bars, mean ± SE. **p < 0.01. (C) Cell cycle analysis shows a significant increase in G2/M cell cycle arrest in NSCLC cells, 48h post-treatment with PLK1 siRNA complexed to L2K. Cells treated with non-functional (Ctrl) siRNA served as controls, n = 3; bars, mean ± SE. **p < 0.01.
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Figure 2: Effect of PLK1 knockdown using siRNA on NSCLC cell death and cell cycle progression(A & B) Representative flow cytometry plots of annexin V staining in NSCLC cells (H1299, H460) and a graph showing an increase in the percentage of cells which stained positive with annexin V, 72h post-transfection with PLK1 siRNA (100 nM) complexed to lipofectamine 2000 (L2K). Cells treated with non-functional (Ctrl) siRNA served as controls. No difference in annexin V staining was observed in normal human lung fibroblasts (MRC-5), 72h post-transfection with PLK1 siRNA complexed to L2K when compared to controls (Ctrl siRNA), n = 3; bars, mean ± SE. **p < 0.01. (C) Cell cycle analysis shows a significant increase in G2/M cell cycle arrest in NSCLC cells, 48h post-treatment with PLK1 siRNA complexed to L2K. Cells treated with non-functional (Ctrl) siRNA served as controls, n = 3; bars, mean ± SE. **p < 0.01.

Mentions: Inhibition of PLK1 has been reported to induce apoptosis in a number of different types of cancer cells via a G2/M cell cycle arrest [5]. To confirm whether the observed decrease in cell proliferation in NSCLC cells following treatment with PLK1 siRNA was associated with increased cell death and/or cell cycle arrest, we treated 2 different NSCLC cell lines (H1299 and H460) with PLK1 siRNA complexed to Lipofectamine 2000 (L2K), and measured apoptosis by annexin V staining and flow cytometry. Cell cycle distribution was also measured by propidium iodide staining and flow cytometry 48h post-PLK1 siRNA transfection. Silencing PLK1 expression using siRNA markedly increased cell death in both H1299 and H460 NSCLC cells, 72h post-transfection when compared to cells treated with control siRNA (Figure 2A and 2B). The increase in cell death correlated to a strong induction in G2/M cell cycle arrest 48h post-treatment (Figure 2C). Interestingly, silencing PLK1 expression using siRNA in normal human lung fibroblasts (MRC-5) did not induce cell death (Figure 2A and 2B and Supplementary Figure 3). This suggests that PLK1 may be playing an important role in regulating NSCLC cell survival. Collectively, these results provide strong evidence that PLK1 is highly expressed in NSCLC cells, and that silencing its expression using siRNA strongly inhibits cell proliferation via an induction of mitotic arrest and cell death.


Therapeutic targeting of polo-like kinase 1 using RNA-interfering nanoparticles (iNOPs) for the treatment of non-small cell lung cancer.

McCarroll JA, Dwarte T, Baigude H, Dang J, Yang L, Erlich RB, Kimpton K, Teo J, Sagnella SM, Akerfeldt MC, Liu J, Phillips PA, Rana TM, Kavallaris M - Oncotarget (2015)

Effect of PLK1 knockdown using siRNA on NSCLC cell death and cell cycle progression(A & B) Representative flow cytometry plots of annexin V staining in NSCLC cells (H1299, H460) and a graph showing an increase in the percentage of cells which stained positive with annexin V, 72h post-transfection with PLK1 siRNA (100 nM) complexed to lipofectamine 2000 (L2K). Cells treated with non-functional (Ctrl) siRNA served as controls. No difference in annexin V staining was observed in normal human lung fibroblasts (MRC-5), 72h post-transfection with PLK1 siRNA complexed to L2K when compared to controls (Ctrl siRNA), n = 3; bars, mean ± SE. **p < 0.01. (C) Cell cycle analysis shows a significant increase in G2/M cell cycle arrest in NSCLC cells, 48h post-treatment with PLK1 siRNA complexed to L2K. Cells treated with non-functional (Ctrl) siRNA served as controls, n = 3; bars, mean ± SE. **p < 0.01.
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Figure 2: Effect of PLK1 knockdown using siRNA on NSCLC cell death and cell cycle progression(A & B) Representative flow cytometry plots of annexin V staining in NSCLC cells (H1299, H460) and a graph showing an increase in the percentage of cells which stained positive with annexin V, 72h post-transfection with PLK1 siRNA (100 nM) complexed to lipofectamine 2000 (L2K). Cells treated with non-functional (Ctrl) siRNA served as controls. No difference in annexin V staining was observed in normal human lung fibroblasts (MRC-5), 72h post-transfection with PLK1 siRNA complexed to L2K when compared to controls (Ctrl siRNA), n = 3; bars, mean ± SE. **p < 0.01. (C) Cell cycle analysis shows a significant increase in G2/M cell cycle arrest in NSCLC cells, 48h post-treatment with PLK1 siRNA complexed to L2K. Cells treated with non-functional (Ctrl) siRNA served as controls, n = 3; bars, mean ± SE. **p < 0.01.
Mentions: Inhibition of PLK1 has been reported to induce apoptosis in a number of different types of cancer cells via a G2/M cell cycle arrest [5]. To confirm whether the observed decrease in cell proliferation in NSCLC cells following treatment with PLK1 siRNA was associated with increased cell death and/or cell cycle arrest, we treated 2 different NSCLC cell lines (H1299 and H460) with PLK1 siRNA complexed to Lipofectamine 2000 (L2K), and measured apoptosis by annexin V staining and flow cytometry. Cell cycle distribution was also measured by propidium iodide staining and flow cytometry 48h post-PLK1 siRNA transfection. Silencing PLK1 expression using siRNA markedly increased cell death in both H1299 and H460 NSCLC cells, 72h post-transfection when compared to cells treated with control siRNA (Figure 2A and 2B). The increase in cell death correlated to a strong induction in G2/M cell cycle arrest 48h post-treatment (Figure 2C). Interestingly, silencing PLK1 expression using siRNA in normal human lung fibroblasts (MRC-5) did not induce cell death (Figure 2A and 2B and Supplementary Figure 3). This suggests that PLK1 may be playing an important role in regulating NSCLC cell survival. Collectively, these results provide strong evidence that PLK1 is highly expressed in NSCLC cells, and that silencing its expression using siRNA strongly inhibits cell proliferation via an induction of mitotic arrest and cell death.

Bottom Line: Polo-like kinase 1 (PLK1) is a serine-threonine protein kinase which is overexpressed in cancer cells, and plays a major role in regulating tumor growth.Notably, iNOP-7 delivered siRNA to orthotopic lung tumors in mice, and administration of iNOP-7-PLK1 siRNA reduced lung tumor burden.These novel data show that iNOP-7 can deliver siRNA against PLK1 to NSCLC cells, and decrease cell proliferation both in vitro and in vivo. iNOP-7-PLK1 siRNA may provide a novel therapeutic strategy for the treatment of NSCLC as well as other cancers which aberrantly express this gene.

View Article: PubMed Central - PubMed

Affiliation: Children's Cancer Institute, Lowy Cancer Research Centre, Randwick, UNSW Australia (UNSW), NSW, Australia.

ABSTRACT
Non-small cell lung cancer (NSCLC) remains the most common cause of cancer death worldwide due its resistance to chemotherapy and aggressive tumor growth. Polo-like kinase 1 (PLK1) is a serine-threonine protein kinase which is overexpressed in cancer cells, and plays a major role in regulating tumor growth. A number of PLK1 inhibitors are in clinical trial; however, poor tumor bioavailability and off-target effects limit their efficacy. Short-interfering-RNA (siRNA) holds promise as a class of therapeutics, which can selectively silence disease-causing genes. However, siRNA cannot enter cells without a delivery vehicle. Herein, we investigated whether RNAi-interfering nanoparticles could deliver siRNA to NSCLC cells and silence PLK1 expression in vitro and in vivo. iNOP-7 was non-toxic, and delivered siRNA with high efficiency to NSCLC cells. iNOP-7-PLK1 siRNA silenced PLK1 expression and reduced NSCLC growth in vitro. Notably, iNOP-7 delivered siRNA to orthotopic lung tumors in mice, and administration of iNOP-7-PLK1 siRNA reduced lung tumor burden. These novel data show that iNOP-7 can deliver siRNA against PLK1 to NSCLC cells, and decrease cell proliferation both in vitro and in vivo. iNOP-7-PLK1 siRNA may provide a novel therapeutic strategy for the treatment of NSCLC as well as other cancers which aberrantly express this gene.

No MeSH data available.


Related in: MedlinePlus