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Endoplasmic reticulum ribosome-binding protein 1, RRBP1, promotes progression of colorectal cancer and predicts an unfavourable prognosis

View Article: PubMed Central - PubMed

ABSTRACT

Background:: Ribosome-binding protein 1 (RRBP1) has been implicated in the regulation of unfolded protein response, which is involved in almost every aspect of cancer development. We aimed to explore the significance of RRBP1 in the progression and prognosis of colorectal cancer (CRC).

Methods:: The study population consisted of 856 patients with stage I–III CRC from two hospitals. RRBP1 expression was examined by immunohistochemisty (IHC) in colorectal tissues. The correlation of RRBP1 expression and CRC occurrence was assessed in paired cancer-adjacent tissues. Factors contributing to prognosis were evaluated in a training-validation design with univariate and multivariate Cox analysis. Colorectal cancer aggressiveness caused by RRBP1 knockdown or overexpression was evaluated in CRC cells.

Results:: RRBP1 was aberrantly overexpressed in CRC. Compared with low-RRBP1 patients, high-RRBP1 patients had shorter disease-specific survival in the training (hazard ratio (HR), 2.423; 95% confidence interval (CI), 1.531–3.835) and validation cohorts (HR, 3.749; 95% CI, 2.166–6.448) in multivariate Cox analysis. High-RRBP1 independently predicted a shorter disease-free survival (HR, 4.821; 95% CI, 3.220–7.218) in the validation cohort. RRBP1 knockdown reduced the aggressiveness of CRC cells in vitro and inhibited the growth of CRC xenografts in vivo.

Conclusions:: High RRBP1 expression facilitates CRC progression and predicts an unfavourable post-operative prognosis.

No MeSH data available.


Related in: MedlinePlus

RRBP1 promotes the growth and aggressiveness of CRC cells. (A) Relative levels of RRBP1 mRNA in CRC cells examined by Q–PCR (upper panel) and western blot (lower panel). (B) Efficiencies of RRBP1 siRNA pairs 1–3 in downregulating RRBP1 expression in SW480 cells were examined by Q–PCR (upper panel) and western blot (lower panel). (C) Similar to (B), CRC cells were transfected with RRBP1-siRNAs and examined for RRBP1 expression by western blot. Otherwise, LoVo cells were transfected with Mock or RRBP1-Myc vector and examined by western blot. IB, immunoblot. (D–F) Colorectal cancer cells in (C) were examined for cell proliferation (D), colony formation (E) and invasiveness (F). (G, H) Colorectal cancer xenografts in Balb/c nude mice. On indicated days after inoculation, RRBP1 expression in representative tumours was examined by western blot (G) and tumour volumes were monitored and presented as mean±s.e.m. (H). (**P<0.01; ***P<0.001; as compared with control cells, ANOVA or unpaired t tests was used.)
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fig3: RRBP1 promotes the growth and aggressiveness of CRC cells. (A) Relative levels of RRBP1 mRNA in CRC cells examined by Q–PCR (upper panel) and western blot (lower panel). (B) Efficiencies of RRBP1 siRNA pairs 1–3 in downregulating RRBP1 expression in SW480 cells were examined by Q–PCR (upper panel) and western blot (lower panel). (C) Similar to (B), CRC cells were transfected with RRBP1-siRNAs and examined for RRBP1 expression by western blot. Otherwise, LoVo cells were transfected with Mock or RRBP1-Myc vector and examined by western blot. IB, immunoblot. (D–F) Colorectal cancer cells in (C) were examined for cell proliferation (D), colony formation (E) and invasiveness (F). (G, H) Colorectal cancer xenografts in Balb/c nude mice. On indicated days after inoculation, RRBP1 expression in representative tumours was examined by western blot (G) and tumour volumes were monitored and presented as mean±s.e.m. (H). (**P<0.01; ***P<0.001; as compared with control cells, ANOVA or unpaired t tests was used.)

Mentions: To explore the roles of RRBP1 in CRC progression, we examined the effects of RRBP1 expression on growth and aggressiveness of CRC cells. RRBP1 is highly expressed in SW480, HT29 and HCT116 cells, but is relatively low in LoVo cells (Figure 3A). Therefore, we decreased RRBP1 expression in SW480, HT29 and HCT116 cells, and overexpressed RRBP1 in LoVo cells. We synthesised three pairs of siRNA specific for RRBP1, and found that the second siRNA pair (referred to as RRBP1 siRNAs) could most efficiently downregulate RRBP1 expression, as examined by both Q–PCR and western blot (Figure 3B). Then, we examined the proliferation, clone formation and invasion of CRC cells transfected with RRBP1 siRNA in vitro (Figure 3C). The results showed that RRBP1 knockdown significantly inhibited the proliferation, colony formation and invasiveness of SW480, HT29 and HCT116 cells (Figure 3D–F). Meanwhile, RRBP1 overexpression significantly promoted the proliferation, colony formation and invasiveness of LoVo cells (Figure 3D–F). To exclude the possible off-target effects, we transiently overexpressed RRBP1 in SW480 cells after RRBP1 knockdown, and found that RRBP1 could rescue the effects of RRBP1 knockdown on cell proliferation (Supplementary Figure 4). These data suggest that RRBP1 may promote the growth and aggressiveness of CRC cells in vitro. To further investigate the effects of RRBP1 on CRC progression, we inoculated SW480, HT29 and HCT116 cells in Balb/c nude mice and treated the neoplasm with RRBP1 siRNAs (Figure 3G). The results showed that RRBP1 siRNA could significantly inhibit the growth of CRC xenografts in vivo (Figure 3H). Consistently, RRBP1-overexpressed LoVo xenografts demonstrated increased growth in nude mice (Figure 3H). These data indicate that RRBP1 is involved CRC progression in vivo and knockdown of RRBP1 may be a potential therapeutic for CRC.


Endoplasmic reticulum ribosome-binding protein 1, RRBP1, promotes progression of colorectal cancer and predicts an unfavourable prognosis
RRBP1 promotes the growth and aggressiveness of CRC cells. (A) Relative levels of RRBP1 mRNA in CRC cells examined by Q–PCR (upper panel) and western blot (lower panel). (B) Efficiencies of RRBP1 siRNA pairs 1–3 in downregulating RRBP1 expression in SW480 cells were examined by Q–PCR (upper panel) and western blot (lower panel). (C) Similar to (B), CRC cells were transfected with RRBP1-siRNAs and examined for RRBP1 expression by western blot. Otherwise, LoVo cells were transfected with Mock or RRBP1-Myc vector and examined by western blot. IB, immunoblot. (D–F) Colorectal cancer cells in (C) were examined for cell proliferation (D), colony formation (E) and invasiveness (F). (G, H) Colorectal cancer xenografts in Balb/c nude mice. On indicated days after inoculation, RRBP1 expression in representative tumours was examined by western blot (G) and tumour volumes were monitored and presented as mean±s.e.m. (H). (**P<0.01; ***P<0.001; as compared with control cells, ANOVA or unpaired t tests was used.)
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fig3: RRBP1 promotes the growth and aggressiveness of CRC cells. (A) Relative levels of RRBP1 mRNA in CRC cells examined by Q–PCR (upper panel) and western blot (lower panel). (B) Efficiencies of RRBP1 siRNA pairs 1–3 in downregulating RRBP1 expression in SW480 cells were examined by Q–PCR (upper panel) and western blot (lower panel). (C) Similar to (B), CRC cells were transfected with RRBP1-siRNAs and examined for RRBP1 expression by western blot. Otherwise, LoVo cells were transfected with Mock or RRBP1-Myc vector and examined by western blot. IB, immunoblot. (D–F) Colorectal cancer cells in (C) were examined for cell proliferation (D), colony formation (E) and invasiveness (F). (G, H) Colorectal cancer xenografts in Balb/c nude mice. On indicated days after inoculation, RRBP1 expression in representative tumours was examined by western blot (G) and tumour volumes were monitored and presented as mean±s.e.m. (H). (**P<0.01; ***P<0.001; as compared with control cells, ANOVA or unpaired t tests was used.)
Mentions: To explore the roles of RRBP1 in CRC progression, we examined the effects of RRBP1 expression on growth and aggressiveness of CRC cells. RRBP1 is highly expressed in SW480, HT29 and HCT116 cells, but is relatively low in LoVo cells (Figure 3A). Therefore, we decreased RRBP1 expression in SW480, HT29 and HCT116 cells, and overexpressed RRBP1 in LoVo cells. We synthesised three pairs of siRNA specific for RRBP1, and found that the second siRNA pair (referred to as RRBP1 siRNAs) could most efficiently downregulate RRBP1 expression, as examined by both Q–PCR and western blot (Figure 3B). Then, we examined the proliferation, clone formation and invasion of CRC cells transfected with RRBP1 siRNA in vitro (Figure 3C). The results showed that RRBP1 knockdown significantly inhibited the proliferation, colony formation and invasiveness of SW480, HT29 and HCT116 cells (Figure 3D–F). Meanwhile, RRBP1 overexpression significantly promoted the proliferation, colony formation and invasiveness of LoVo cells (Figure 3D–F). To exclude the possible off-target effects, we transiently overexpressed RRBP1 in SW480 cells after RRBP1 knockdown, and found that RRBP1 could rescue the effects of RRBP1 knockdown on cell proliferation (Supplementary Figure 4). These data suggest that RRBP1 may promote the growth and aggressiveness of CRC cells in vitro. To further investigate the effects of RRBP1 on CRC progression, we inoculated SW480, HT29 and HCT116 cells in Balb/c nude mice and treated the neoplasm with RRBP1 siRNAs (Figure 3G). The results showed that RRBP1 siRNA could significantly inhibit the growth of CRC xenografts in vivo (Figure 3H). Consistently, RRBP1-overexpressed LoVo xenografts demonstrated increased growth in nude mice (Figure 3H). These data indicate that RRBP1 is involved CRC progression in vivo and knockdown of RRBP1 may be a potential therapeutic for CRC.

View Article: PubMed Central - PubMed

ABSTRACT

Background:: Ribosome-binding protein 1 (RRBP1) has been implicated in the regulation of unfolded protein response, which is involved in almost every aspect of cancer development. We aimed to explore the significance of RRBP1 in the progression and prognosis of colorectal cancer (CRC).

Methods:: The study population consisted of 856 patients with stage I&ndash;III CRC from two hospitals. RRBP1 expression was examined by immunohistochemisty (IHC) in colorectal tissues. The correlation of RRBP1 expression and CRC occurrence was assessed in paired cancer-adjacent tissues. Factors contributing to prognosis were evaluated in a training-validation design with univariate and multivariate Cox analysis. Colorectal cancer aggressiveness caused by RRBP1 knockdown or overexpression was evaluated in CRC cells.

Results:: RRBP1 was aberrantly overexpressed in CRC. Compared with low-RRBP1 patients, high-RRBP1 patients had shorter disease-specific survival in the training (hazard ratio (HR), 2.423; 95% confidence interval (CI), 1.531&ndash;3.835) and validation cohorts (HR, 3.749; 95% CI, 2.166&ndash;6.448) in multivariate Cox analysis. High-RRBP1 independently predicted a shorter disease-free survival (HR, 4.821; 95% CI, 3.220&ndash;7.218) in the validation cohort. RRBP1 knockdown reduced the aggressiveness of CRC cells in vitro and inhibited the growth of CRC xenografts in vivo.

Conclusions:: High RRBP1 expression facilitates CRC progression and predicts an unfavourable post-operative prognosis.

No MeSH data available.


Related in: MedlinePlus