Intravesical administration of small interfering RNA targeting PLK-1 successfully prevents the growth of bladder cancer
Masaki Nogawa, Takeshi Yuasa, Shinya Kimura, Motoyoshi Tanaka, Junya Kuroda, Kiyoshi Sato, Asumi Yokota, Hidekazu Segawa, Yoshinobu Toda, Susumu Kageyama, Tatsuhiro Yoshiki, Yusaku Okada, Taira Maekawa
Masaki Nogawa, Takeshi Yuasa, Shinya Kimura, Motoyoshi Tanaka, Junya Kuroda, Kiyoshi Sato, Asumi Yokota, Hidekazu Segawa, Yoshinobu Toda, Susumu Kageyama, Tatsuhiro Yoshiki, Yusaku Okada, Taira Maekawa
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Article Oncology

Intravesical administration of small interfering RNA targeting PLK-1 successfully prevents the growth of bladder cancer

Abstract

The mainstay in the management of invasive bladder cancer continues to be radical cystectomy. With regard to improvement of quality of life, however, therapies that preserve the bladder are desirable. We investigated the use of intravesical PLK-1 small interfering RNA (siRNA) against bladder cancer. Patients with bladder cancers expressing high levels of PLK-1 have a poor prognosis compared with patients with low expression. Using siRNA/cationic liposomes, the expression of endogenous PLK-1 could be suppressed in bladder cancer cells in a time- and dose-dependent manner. As a consequence, PLK-1 functions were disrupted. Inhibition of bipolar spindle formation, accumulation of cyclin B1, reduced cell proliferation, and induction of apoptosis were observed. In order to determine the efficacy of the siRNA/liposomes in vivo, we established an orthotopic mouse model using a LUC-labeled bladder cancer cell line, UM-UC-3LUC. PLK-1 siRNA was successfully transfected into the cells, reduced PLK-1 expression, and prevented the growth of bladder cancer in this mouse model. This is the first demonstration, to our knowledge, of inhibition of cancer growth in the murine bladder by intravesical siRNA/cationic liposomes. We believe intravesical siRNA instillation against bladder cancer will be useful as a therapeutic tool.

Authors

Masaki Nogawa, Takeshi Yuasa, Shinya Kimura, Motoyoshi Tanaka, Junya Kuroda, Kiyoshi Sato, Asumi Yokota, Hidekazu Segawa, Yoshinobu Toda, Susumu Kageyama, Tatsuhiro Yoshiki, Yusaku Okada, Taira Maekawa

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Growth inhibition of bladder cancer by PLK-1 siRNA in orthotopic bladder...
Growth inhibition of bladder cancer by PLK-1 siRNA in orthotopic bladder cancer mouse models. (A) Images were obtained by IVIS at 10 minutes, 1 day, 1 week, 3 weeks, and 4 weeks after transplantation. The photon counts of each mouse are indicated by the pseudo-color scales. (B) FITC-labeled control siRNA with cationic liposomes was successfully transfected into bladder cancer cells as shown by immune staining using an anti-FITC antibody (top left panel). H&:E counterstaining was performed to identify cancer cells (top right panel). The same experiments were performed without cationic liposomes (bottom panels). Original magnification, ×400. (C) Immunohistochemical staining revealed that intravesical PLK-1 siRNA/liposome complexes successfully reduced PLK-1 expression (top left panel). H&:E counterstaining was performed to identify cancer cells (top right panel). The same experiments were performed with the complex of control siRNA and liposomes (bottom panels). Original magnification, ×400. (D) The growth curves of orthotopically transplanted UM-UC-3LUC cells were measured by IVIS. The anticancerous effect of intravesical PLK-1 siRNA was demonstrated in vivo. Open squares, no treatment; filled squares, treatment with control siRNA (6 μM); open circles, treatment with PLK-1 siRNA (6 μM); filled circles, treatment with PLK-1 siRNA (600 nM). The data shown are representative of duplicate experiments. (E) Pathological analysis was performed in UM-UC-3LUC–transplanted murine bladder tissues after PLK-1 siRNA treatment. Residual cancer (top left and middle panels) and noncancerous bladder (top right and lower panels) were observed microscopically. Numbers indicate original magnification. (F) No apparent induction of IFN-β gene expression by either PLK-1 or control siRNAs was observed in RAW264.7 cells.