In vivo pre-activation of monocytes in patients with axial spondyloarthritis

IntroductionInnate immune responses, including monocyte functions, seem to play an important role in the pathogenesis of axial spondyloarthritis (axSpA). Therefore, we characterized the phenotype and functional state of monocytes of patients with axSpA.MethodsFifty-seven patients with axSpA, 11 patients with rheumatoid arthritis (RA), and 29 healthy controls were included in the study. We determined the percentage of classic, intermediate, and non-classic monocytes according to CD14 and CD16 expression and the expression of Toll-like receptor (TLR) 1, 2, and 4 in whole blood by flow cytometry. The percentage of monocytes producing interleukin (IL)-1beta, IL-6, tumor necrosis factor alpha (TNFα), IL-12/23p40, and IL-1 receptor antagonist (IL-1ra) was detected by flow cytometry after stimulation of whole blood without and with different TLR and nucleotide-binding oligomerization domain ligands—i.e., lipopolysaccharide (LPS), fibroblast-stimulating lipopeptid-1, PAM₃CSK₄, and muramyl dipeptide (MDP)—for 5 h. IL-10 production was measured after 18 h of stimulation in supernatants by enzyme-linked immunosorbent assay.ResultsIn patients with axSpA but not patients with RA, we found higher frequencies of classic monocytes than in controls (median of 90.4 % versus 80.4 %, P < 0.05), higher frequencies of monocytes spontaneously producing IL-1beta and IL-1ra (P < 0.05), and a higher percentage of monocytes producing IL-1beta after MDP stimulation (P < 0.05). Elevated cytokine production was confined to axSpA patients under conventional therapy (non-steroidal anti-inflammatory drugs) and not found in patients under TNFα inhibitor treatment. The LPS-induced production of IL-6 and IL-10 was lower in axSpA patients compared with controls (P < 0.05). Monocytic TLR expression was unaffected in patients with axSpA.ConclusionEnhanced spontaneous and MDP-induced cytokine secretion by monocytes suggests in vivo pre-activation of monocytes in axSpA patients under conventional therapy which is reverted under TNF inhibitor treatment.     

Enhanced activity of NLRP3 inflammasome in peripheral blood cells of patients with active rheumatoid arthritis

IntroductionInterleukin-1β (IL-1β) is a major inflammatory cytokine, produced predominantly by innate immune cells through NLRP3-inflammasome activation. Both intrinsic and extrinsic danger signals may activate NLRP3. Genetic variations in NLRP3-inflammasome components have been reported to influence rheumatoid arthritis (RA) susceptibility and severity. We sought to assess the activity of NLRP3-inflammasome in patients with active RA compared to healthy individuals.MethodIntracellular protein expression of NLRP3, ASC, pro- and active caspase-1, pro- and active IL-1β was assessed by immunoblotting both at baseline and upon inflammasome activation. NLRP3 function (IL-1β secretion) was assessed upon priming of TLR2 (Pam(3)CysSK(4), TLR3 (poly(I:C)) or TLR4 (LPS) and ATP sequential treatment. We used caspase inhibitors (casp-1, 3/7 and 8) to assess their contribution to IL-1β maturation. All experiments were performed in whole blood cells.ResultsActive RA patients (n = 11) expressed higher basal intracellular levels of NLRP3 (p < 0.008), ASC (p < 0.003), active caspase-1 (p < 0.02) and pro-IL-1β (p < 0.001). Upon priming with TLR4 (LPS) and ATP, RA-derived cell extracts (n = 7) displayed increased expression of NLRP3 (p < 0.01) and active caspase-1 (p < 0.001). Secreted IL-1β in culture supernatants from whole blood cells activated with TLR4 (LPS) or TLR3 agonist (poly(I:C)) plus ATP was higher in RA patients (n = 20) versus controls (n = 18) (p < 0.02 for both). Caspase-1 inhibition significantly reduced IL-1β secretion induced by all stimuli, whereas caspase-8 inhibition affected only TLR4 and TLR3 cell priming.ConclusionPatients with active RA have increased expression of NLRP3 and NLRP3-mediated IL-1β secretion in whole blood cells upon stimulation via TLR3 and TLR4 but not TLR2. In these patients, IL-1β secretion seems to be predominately driven by caspase-1 and caspase-8. Targeting NLRP3 or downstream caspases may be of benefit in suppressing IL-1β production in RA.     

Differential expression of Toll-like receptors on human alveolar macrophages and autologous peripheral monocytes

Background

Toll-like receptors (TLRs) are critical components in the regulation of pulmonary immune responses and the recognition of respiratory pathogens such as Mycobacterium Tuberculosis (M.tb). Through examination of human alveolar macrophages this study attempts to better define the expression profiles of TLR2, TLR4 and TLR9 in the human lung compartment which are as yet still poorly defined.

Methods

Sixteen healthy subjects underwent venipuncture, and eleven subjects underwent additional bronchoalveolar lavage to obtain peripheral blood mononuclear and bronchoalveolar cells, respectively. Surface and intracellular expression of TLRs was assessed by fluorescence-activated cell sorting and qRT-PCR. Cells were stimulated with TLR-specific ligands and cytokine production assessed by ELISA and cytokine bead array.

Results

Surface expression of TLR2 was significantly lower on alveolar macrophages than on blood monocytes (1.2 ± 0.4% vs. 57 ± 11.1%, relative mean fluorescence intensity [rMFI]: 0.9 ± 0.1 vs. 3.2 ± 0.1, p < 0.05). The proportion of TLR4 and TLR9-expressing cells and the rMFIs of TLR4 were comparable between alveolar macrophages and monocytes. The surface expression of TLR9 however, was higher on alveolar macrophages than on monocytes (rMFI, 218.4 ± 187.3 vs. 4.4 ± 1.4, p < 0.05) while the intracellular expression of the receptor and the proportion of TLR9 positive cells were similar in both cell types. TLR2, TLR4 and TLR9 mRNA expression was lower in bronchoalveolar cells than in monocytes.Pam3Cys, LPS, and M.tb DNA upregulated TLR2, TLR4 and TLR9 mRNA in both, bronchoalveolar cells and monocytes. Corresponding with the reduced surface and mRNA expression of TLR2, Pam3Cys induced lower production of TNF-α, IL-1β and IL-6 in bronchoalveolar cells than in monocytes. Despite comparable expression of TLR4 on both cell types, LPS induced higher levels of IL-10 in monocytes than in alveolar macrophages. M.tb DNA, the ligand for TLR9, induced similar levels of cytokines in both cell types.

Conclusion

The TLR expression profile of autologous human alveolar macrophages and monocytes is not identical, therefore perhaps contributing to compartmentalized immune responses in the lungs and systemically. These dissimilarities may have important implications for the design and efficacy evaluation of vaccines with TLR-stimulating adjuvants that target the respiratory tract.     

Selenoproteins and heat shock proteins play important roles in immunosuppression in the bursa of Fabricius of chickens with selenium deficiency

Selenium (Se) is necessary for the immune system in chicken and mediates its physiological functions through selenoproteins. Heat shock proteins (Hsps) are indispensable for maintaining normal cell function and for directing the immune response. The aim of the present study was to investigate the effects of Se deficiency on the messenger ribonucleic acid (mRNA) expression levels of selenoproteins and Hsps as well as immune functions in the chicken bursa of Fabricius. Two groups of chickens, namely the control and Se-deficient (L group) groups, were reared for 55 days. The chickens were offered a basal diet, which contained 0.15 mg Se/kg in the diet fed to the control group and 0.033 mg Se/kg in the diet fed to the L group. We performed real-time quantitative polymerase chain reactionto detect the mRNA expression levels of selenoproteins and Hsps on days 15, 25, 35, 45 and 55. Western blotting was used to determine the protein expression levels of Hsps on days 35, 45 and 55, and immune functions were assessed through an enzyme-linked immunosorbent assay on days 15, 35, and 55. The data showed that the mRNA expression levels of selenoproteins, such as Txnrd1, Txnrd2, Txnrd3, Dio1, Dio2, Dio3, GPx1, GPx2, GPx3 GPx4, Sepp1, Selo, Sel-15, Sepx1, Sels, Seli, Selu, Selh, and SPS2, were significantly lower (P < 0.05) in the L group compared with the control group. Additionally, the mRNA and protein expression levels of Hsps (Hsp27, Hsp40, Hsp60, Hsp70, and Hsp90) were also significantly higher (P < 0.05) in the L group. The expression levels of IL-2, IL-6, IL-8, IL-10, IL-17, IL-1β, IFN-α, IFN-β, and IFN-γ were significantly lower (P < 0.05) and TNF-α was significantly higher (P < 0.05) in the L group compared with the control group. Our results show that immunosuppression was accompanied by a downregulation of mRNA expression levels of selenoproteins and an upregulation of the Hsp mRNA expression levels. Thus, Se deficiency causes defects in the chicken bursa of Fabricius, and selenoproteins and Hsps play important roles in immunosuppression in the bursa of Fabricius of chickens with Se deficiency.     

Mechanism of programmed cell death factor 4/nuclear factor-κB signaling pathway in porcine coronary micro-embolization-induced cardiac dysfunction

The aim of this study was to investigate the role of the programmed cell death factor 4 (PDCD4)/nuclear factor-κB (NF-κB) signaling pathway in coronary micro-embolism (CME)-induced inflammatory responses and cardiac dysfunction in a porcine model. Bama miniature pigs were randomly divided into four groups (n = 5 per group). Micro-embolization balls or saline were infused through a microcatheter in the left anterior descending (LAD) artery in the CME and Sham groups, respectively. PDCD4 siRNA or control siRNA mixed with transfection reagent was infused via the LAD artery 72 h before CME induction in the CME + siRNA-PDCD4 and siRNA-control groups, respectively. Cardiac function was evaluated with ultrasound. Tissue biopsy was stained with hematoxylin–eosin (HE) and hematoxylin basic fuchsin picric acid (HBFP) to measure infarction area. Myocardial PDCD4 and tumor necrosis factor-α (TNF-α) mRNA and protein expression were analyzed by quantitative PCR and Western blotting. NF-κB activity was evaluated in gel electrophoretic mobility shift assay. Echocardiographic parameters showed that compared with the sham group, the CME group had impaired heart function, manifested as systolic dysfunction and left ventricular dilatation (reduced left ventricular ejection fraction [LVEF], left ventricular fractional shortening [FS], and cardiac output [CO] [P < 0.05] and increased left ventricular end-diastolic diameter [LVEDd] [P < 0.05]). Compared with the CME group, the CME + siRNA-PDCD4 group had attenuated CME-induced cardiac function damage (increased LVEF, FS and CO [P < 0.05] and reduced LVEDd [P < 0.05]). Compared with the sham group, the CME group had significantly increased PDCD4 and TNF-α mRNA and protein expression and increased NF-κB activity (P < 0.05). These effects were significantly inhibited in the CME + siRNA-PDCD4 group (P < 0.05). In conclusion, PDCD4/NF-κB signaling pathway activation is an important mechanism for CME-induced cardiac dysfunction, suggesting that inhibition of PDCD4/NF-κB signaling pathway may be a potential target for the prevention and treatment of CME.     

The natural organosulfur compound dipropyltetrasulfide prevents HOCl-induced systemic sclerosis in the mouse

Introduction

The aim of this study was to test the naturally occurring organosulfur compound dipropyltetrasulfide (DPTTS), found in plants, which has antibiotic and anticancer properties, as a treatment for HOCl-induced systemic sclerosis in the mouse.

Methods

The prooxidative, antiproliferative, and cytotoxic effects of DPTTS were evaluated ex vivo on fibroblasts from normal and HOCl mice. In vivo, the antifibrotic and immunomodulating properties of DPTTS were evaluated in the skin and lungs of HOCl mice.

Results

H₂O₂ production was higher in fibroblasts derived from HOCl mice than in normal fibroblasts (P < 0.05). DPTTS did not increase H₂O₂ production in normal fibroblasts, but DPTTS dose-dependently increased H₂O₂ production in HOCl fibroblasts (P < 0.001 with 40 μM DPTTS). Because H₂O₂ reached a lethal threshold in cells from HOCl mice, the antiproliferative, cytotoxic, and proapoptotic effects of DPTTS were significantly higher in HOCl fibroblasts than for normal fibroblasts. In vivo, DPTTS decreased dermal thickness (P < 0.001), collagen content in skin (P < 0.01) and lungs (P < 0.05), αSMA (P < 0.01) and pSMAD2/3 (P < 0.01) expression in skin, formation of advanced oxidation protein products and anti-DNA topoisomerase-1 antibodies in serum (P < 0.05) versus untreated HOCl mice. Moreover, in HOCl mice, DPTTS reduced splenic B-cell counts (P < 0.01), the proliferative rates of B-splenocytes stimulated by lipopolysaccharide (P < 0.05), and T-splenocytes stimulated by anti-CD3/CD28 mAb (P < 0.001). Ex vivo, it also reduced the production of IL-4 and IL-13 by activated T cells (P < 0.05 in both cases).

Conclusions

The natural organosulfur compound DPTTS prevents skin and lung fibrosis in the mouse through the selective killing of diseased fibroblasts and its immunomodulating properties. DPTTS may be a potential treatment for systemic sclerosis.     

Effects of GHRP-2 and Cysteamine Administration on Growth Performance,Somatotropic Axis Hormone and Muscle Protein Deposition in Yaks (Bos grunniens) with Growth Retardation

The objective of this study was to investigate the effects of growth hormone-releasing peptide-2 (GHRP-2) and cysteamine (CS) administration on growth performance in yaks with growth retardation and try to elucidate its regulatory mechanisms. Trial 1, thirty-six 1-year-old Qinghai high plateau yaks (body weight 38–83.2 kg) were randomly chosen for body weight and jugular blood samples collection. The relationship between body weight and serum GHRH (P < 0.05, R = 0.45), GH (P < 0.05, R = 0.47), IGF-1 (P < 0.05, R = 0.62) was significantly correlated in yaks colonies with lighter body weights. Trial 2, fifteen 1-year-old Qinghai high plateau yaks with growth retardation (average body weight 54.8 ± 8.24 kg) were randomly selected and assigned to negative control group (NG), GHRP-2 injection group (GG) and cysteamine feeding group (CG), with 5 yaks per group. Another five 1-year-old Qinghai high plateau yaks with normal growth performance (average body weight 75.3 ± 2.43 kg) were selected as positive control group (PG). The average daily gain (ADG) of the GG and CG were significantly higher than those in the PG and NG (P < 0.05). Both GHRP-2 and CS administration significantly enhanced the myofiber diameter and area of skeletal muscle (P<0.05). GHRP-2 significantly enhanced the serum GH and IGF-1 levels (P < 0.05), and up-regulated GHR, IGF-1 and IGF-1R mRNA expression in the liver and skeletal muscle (P < 0.05), enhanced the mRNA expression of PI₃K, AKt and mTOR in the skeletal muscle (P<0.05). CS significantly reduced the serum SS levels and the hypothalamus SS mRNA expression (P < 0.05), and enhanced GHR and IGF-1 mRNA expression in the liver (P < 0.05), decreased the mRNA expression of muscle atrophy F-box (Atrogin-1) and muscle ring finger 1 (MuRF1) mRNA (P < 0.05). Conclusions: Growth retardation in yaks was primarily due to somatotropic axis hormones secretion deficiency. Both GHRP-2 and CS administration can accelerate growth performance and GH, IGF-1 secretion in yaks with growth retardation. GHRP-2 enhanced muscle protein deposition mainly by up-regulated the protein synthesis pathways, whereas CS worked mainly by down-regulated the ubiquitin-proteasome pathway.     

RhoA/Rho-Kinase and Nitric Oxide in Vascular Reactivity in Rats with Endotoxaemia

RhoA/Rho-kinase (RhoA/ROK) pathway promotes vasoconstriction by calcium sensitivity mechanism. LPS causes nitric oxide (NO) overproduction to induce vascular hyporeactivity. Thus, we tried to examine the role of RhoA/ROK and NO in the regulation of vascular reactivity in different time-point of endotoxaemia. Male Wistar rats were intravenously infused for 10 min with saline or E. coli endotoxin (lipopolysaccharide, LPS, 10 mg/kg) and divided to five groups (n = 8 in each group): (i) Control, sacrificed at 6 h after saline infusion; (ii) LPS1h, sacrificed at 1 h after LPS infusion; (iii) LPS2h, sacrificed at 2 h after LPS infusion; (iv) LPS4h, sacrificed at 4 h after LPS infusion; and (v) LPS6h, sacrificed at 6 h after LPS infusion. LPS1h and LPS2h were regarded as early endotoxaemia, whereas LPS4h and LPS6h were regarded as late endotoxaemia. Indeed, our results showed that LPS reproduced a biphasic hypotension and sustained vascular hyporeactivity to noradrenaline (NA) in vivo. Interestingly, this hyporeactivity did not occur in ex vivo during early endotoxaemia. This could be due to increases of aortic RhoA activity (n = 5, P<0.05) and myosin phosphatase targeting subunit 1 phosphorylation (n = 3, P<0.05). In addition, pressor response to NA and vascular reactivity in early endotoxaemia were inhibited by ROK inhibitor, Y27632. Furthermore, plasma bradykinin was increased at 10 min (24.6±13.7 ng/mL, n = 5, P<0.05) and aortic endothelial NO synthase expression was increased at 1 h (+200%. n = 3, P<0.05) after LPS. In late endotoxaemia, the vascular hyporeactivity was associated with aortic inducible NO synthase expression (n = 3, P<0.05) and an increased serum NO level (n = 8, P<0.05). Thus, an increased RhoA activity could compensate vascular hyporeactivity in early endotoxaemia, and the large NO production inhibiting RhoA activity would lead to vascular hyporeactivity eventually.     

The liver X receptor agonist TO901317 protects mice against cisplatin-induced kidney injury

Liver X receptors are in the nuclear receptor superfamily and are contained in the regulation of lipid and cholesterol metabolism. Besides, liver X receptors are considered crucial regulators of the inflammatory response and innate immunity. The current study evaluates the in vivo effects that the synthetic liver X receptor agonist TO901317 protects against cisplatin-induced kidney injury in mice. Mice received cisplatin administration through a single intraperitoneal injection (20 mg/kg in saline). And then the mice were treated with the TO901317 by daily gavage (10 mg/kg/day) 12 h postcisplatin administration, and cisplatin nephrotoxicity was evaluated. At 72 h after cisplatin treatment, elevated plasma urea and creatinine levels (P < 0.05) were evidenced which indicates the renal dysfunction of the vehicle-treated mice, consistent with tubular necrosis, protein cast, dilation of renal tubules, and desquamation of epithelial cells in renal tubules. In contrast, the severity of renal dysfunction and histological damage was reduced in TO901317 treated mice (P < 0.05). In accordance, circulating tumor necrosis factor alpha levels, renal tumor necrosis factor alpha, p47^phox, gp91^phox, and protein expression levels and COX-2 mRNA, renal monocyte chemoattractant protein 1, VACAM-1 mRNA and intercellular adhesion molecule-1 contents, and renal prostaglandin E₂ amounts, were higher in samples from cisplatin-treated mice in comparison with controls (P < 0.05) but attenuated in the TO901317 treatment group (P < 0.05). Taken together, treatment with the liver X receptor agonist TO901317 ameliorated the inflammatory response and oxidative stress in cisplatin-induced kidney injury in mice.     

An alternative miRISC targets a cancer‐associated coding sequence mutation in FOXL2

The authors note that P values presented in the original Fig 1A and Appendix Fig S1A were not assessed using a proper statistical analysis method. In contrast to the initially employed two‐group t‐test, a one‐sample one‐tailed t‐test is appropriate here, as the basic null hypothesis is that the proportion of MT FOXL2 mRNA in each AGCT patient is lower than WT {H ₀: WT(%) > MT(%) }. New p values are presented in the corrected Fig 1A and Appendix Fig S1A, which are P < 0.00001 and P < 0.05, respectively. These revised P values did not affect the conclusion drawn.     

MicroRNA-218 Inhibits Cell Cycle Progression and Promotes Apoptosis in Colon Cancer by Downregulating BMI1 Polycomb Ring Finger Oncogene

Deregulated miRNAs participate in colorectal carcinogenesis. In this study, miR-218 was found to be downregulated in human colorectal cancer (CRC) by miRNA profile assay. miR-218 was silenced or downregulated in all five colon cancer cells (Caco2, HT29, SW620, HCT116 and LoVo) relative to normal colon tissues. miR-218 expression was significantly lower in 46 CRC tumor tissues compared with their adjacent normal tissues (P < 0.001). Potential target genes of miR-218 were predicted and BMI1 polycomb ring finger oncogene (BMI-1), a polycomb ring finger oncogene, was identified as one of the potential targets. Upregulation of BMI-1 was detected in CRC tumors compared with adjacent normal tissues (P < 0.001) and in all five colon cancer cell lines. Transfection of miR-218 in colon cancer cell lines (HCT116, HT29) significantly reduced luciferase activity of the wild-type construct of BMI-1 3′ untranslated region (3′UTR) (P < 0.001), whereas this effect was not seen in the construct with mutant BMI-1 3′UTR, indicating a direct and specific interaction of miR-218 with BMI-1. Ectopic expression of miR-218 in HCT116 and HT29 cells suppressed BMI-1 mRNA and protein expression. In addition, miR-218 suppressed protein expression of BMI-1 downstream targets of cyclin-dependent kinase 4, a cell cycle regulator, while upregulating protein expression of p53. We further revealed that miR-218 induced apoptosis (P < 0.01), inhibited cell proliferation (P < 0.05) and promoted cell cycle arrest in the G2 phase (P < 0.01). In conclusion, miR-218 plays a pivotal role in CRC development through inhibiting cell proliferation and cycle progression and promoting apoptosis by downregulating BMI-1.     

Bone mass and quality in patients with juvenile idiopathic arthritis: longitudinal evaluation of bone-mass determinants by using dual-energy x-ray absorptiometry,peripheral quantitative computed tomography,and quantitative ultrasonography

Introduction

Our objective was to evaluate longitudinally the main bone-mass and quality predictors in young juvenile idiopathic arthritis (JIA) patients by using lumbar spine dual-energy X-ray absorptiometry (DXA) scan, radius peripheral quantitative computed tomography (pQCT), and phalangeal quantitative ultrasonography (QUS) at the same time.

Methods

In total, 245 patients (172 females, 73 males; median age, 15.6 years: 148 oligoarticular, 55 polyarticular, 20 systemic, and 22 enthesitis-related-arthritis (ERA) onset) entered the study. Of these, 166 patients were evaluated longitudinally. Data were compared with two age- and sex-matched control groups.

Results

In comparison with controls, JIA patients, but not with ERA, had a reduced spine bone-mineral apparent density (BMAD) standard deviation score (P < 0.001) and musculoskeletal deficits, with significantly lower levels of trabecular bone mineral density (TrabBMD) (P < 0.0001), muscle cross-sectional area (CSA) (P < 0.005), and density-weighted polar section modulus (SSIp) (P < 0.05). In contrast, JIA showed fat CSA significantly higher than controls (P < 0.0001). Finally, JIA patients had a significant reduced amplitude-dependent speed of sound (AD-SoS) (P < 0.001), and QUS z score (P < 0.005).Longitudinally, we did not find any difference in all JIA patients in comparison with baseline, except for the SSIp value that normalized. Analyzing the treatments, a significant negative correlation among spine BMAD values, TrabBMD, AD-SoS, and systemic and/or intraarticular corticosteroids, and a positive correlation among TNF-α-blocking agents and spine BMAD, TrabBMD, and AD-SoS were observed.

Conclusions

JIA patients have a low bone mass that, after a first increase due to the therapy, does not reach the normal condition over time. The pronounced bone deficits in JIA are greater than would be expected because of reduction in muscle cross-sectional area. Thus, bone alterations in JIA likely represent a mixed defect of bone accrual and lower muscle forces.     

Role of Raf-kinase inhibitor protein in colorectal cancer and its regulation by hydroxycamptothecine

Background

Recently accumulated evidence suggests that Raf kinase inhibitor protein (RKIP) participates in regulation of many signaling pathways and plays an important role in tumorigenesis and tumor metastasis. However, studies investigating the role of RKIP in colorectal cancer have not been reported. The aim of this study was to investigate the role of RKIP on colorectal cancer cell differentiation, progression and its correlation with chemosensitivity.

Results

Immunohistochemical analysis revealed that RKIP expression was higher in non-neoplastic colorectal tissue (NCRCT) and colorectal cancer tissue (CRCT) than that in metastatic lymph node tissue (MLNT) (P <0.05). P-ERK protein expression was higher in MLNT and CRCT than that in NCRCT (P = 0.02). Immunocytochemical analysis further revealed that RKIP expression was higher in the well differentiated cell line SW1116 as compared to that in the poorly differentiated cell line LoVo. Matrigel invasive assay demonstrated that the inhibition of RKIP by short hairpin RNA (shRNA) 271 transfection significantly increased the number of migrated cells (90.67 ± 4.04 vs. 37.33 ± 2.51, P <0.05), whereas over-expression of RKIP by PEBP-1 plasmid transfection significantly suppressed the number of migrated cells (79.24 ± 5.18 vs. 154.33 ± 7.25, P <0.05). Meanwhile, down-regulation of RKIP induced an increase in the cell survival rate by inhibiting apoptosis induced by hydroxycamptothecine.

Conclusions

RKIP was also found to be associated with cell differentiation, with a higher activity in well differentiated colorectal cancer cells than in poorly differentiated ones. The upregulated expression of RKIP in colorectal cancer cells inhibited cell invasion and metastasis, while downregulation of RKIP reduced chemosensitivity by inhibiting apoptosis induced by HCPT.