Knockdown of PKM2 and GLS1 expression can significantly reverse oxaliplatin-resistance in colorectal cancer cells.

Clinical treatment for colorectal cancer (CRC) thus far encounters a huge challenge due to oxaliplatin-resistance. As crucial rate-limiting enzymes in aerobic glycolysis and glutaminolysis, pyruvate kinase M2 type (PKM2) and kidney-type glutaminase (GLS1) are proposed to carry important implications in colorectal carcinogenesis and drug-resistance. This study aimed to explore the possible association of oxaliplatin-resistance with aerobic glycolysis/glutaminolysis indexed by PKM2/GLS1 expression. PKM2 and GLS1 expression was quantified by polymerase chain reaction (PCR) and Western blot techniques in CRC cell lines. The abilities of cell formation, kinetics, migration, invasion, survival and apoptosis, as well as permeability glycoprotein (Pgp) expression were inspected before and after knocking-down PKM2/GLS1 expression. In addition, the influence of knocking-down PKM2/GLS1 expression was evaluated in vivo. Differentiated PKM2 and GLS1 expression in both THC8307 and THC8307/Oxa cell lines was identified. In the THC8307 cell line, PKM2 and GLS1 can accelerate malignant behaviors, increase oxaliplatin-resistance, upregulate Pgp expression, and inhibit cell apoptosis. Contrastingly in the THC8307/Oxa cell line, knockdown of PKM2/GLS1 expression can restrain malignant behaviors, reestablish oxaliplatin-sensitivity, downregulate Pgp expression, and induce cell apoptosis. In xenograft, knockdown of PKM2/GLS1 expression can significantly inhibit tumor growth, reduce Pgp expression, and increase tumor apoptosis. Taken together, the present findings enriched our knowledge by demonstrating a significant association of PKM2 and GLS1 with oxaliplatin-resistance in CRC. We further propose that knockdown of PKM2/GLS1 expression may constitute a novel therapeutic strategy toward effective treatment for CRC.

Enhanced circulating transforming growth factor beta 1 is causally associated with an increased risk of hepatocellular carcinoma: a mendelian randomization meta-analysis.

The aim of this study was to test the causal association between circulating transforming growth factor beta 1 (protein: TGF-ß1 and coding gene: TGFB1) and hepatocellular carcinoma by choosing TGFB1 gene C-509T polymorphism as an instrument in a Mendelian randomization (MR) meta-analysis. Ten English articles were identified for analysis. Two authors independently assessed each article and abstracted relevant data. Odds ratio (OR) and weighted mean difference (WMD) with 95% confidence interval (CI) were synthesized under a random-effects model. Overall, the association of C-509T polymorphism with hepatocellular carcinoma was negative, but its association with circulating TGF-ß1 was statistically significant, with a higher concentration observed in carriers of the -509TT genotype (WMD, 95% CI, P: 1.72, 0.67-2.78, 0.001) and -509TT/-509TC genotypes (WMD, 95% CI, P: 0.98, 0.43-1.53, < 0.001). In subgroup analysis, C-509T polymorphism was significantly associated with hepatocellular carcinoma in population-based studies under homozygous-genotype (OR, 95% CI, P: 1.74, 1.08-2.80, 0.023) and dominant (OR, 95% CI, P: 1.48, 1.01-2.17, 0.047) models. Further MR analysis indicated that per unit increase in circulating TGF-ß1 was significantly associated with a 38% (95% CI: 1.03-4.65) and 49% (95% CI: 1.01-6.06) increased risk of hepatocellular carcinoma under homozygous-genotype and dominant models, respectively. Conclusively, based on a MR meta-analysis, our findings suggest that enhanced circulating TGF-ß1 is causally associated with an increased risk of hepatocellular carcinoma.

[Influence of oxaliplatin combined with LCP on proliferation and apoptosis of colon cancer cell line HT29].

OBJECTIVE: To study the effects of oxaliplatin combined with low-molecular-weight citrus pectin (LCP) on cell proliferation and apoptosis in human colon carcinoma cell line HT29 in vitro. METHODS: Effects of oxaliplatin alone and oxaliplatin combined with LCP on HT29 cells proliferation were determined by MTT. Coefficient of drug interaction (CDI) was calculated. Influence of oxaliplatin alone and oxaliplatin combined with LCP on HT29 cell apoptosis was determined by fluorescence activated cell sorting (FACS). Protein expression change of procaspase-3, 8, 9, PARP was examined by Western blotting. RESULTS: Both oxaliplatin alone and oxaliplatin combined with LCP could suppress HT29 cell proliferation in both dose- and time-dependent manner. The inhibitory effect of oxaliplatin combined with LCP on HT29 cell proliferation was more significant (P<0.01) with a CDI less than 1. FACS analysis showed that oxaliplatin alone and combination therapy could increase the apoptosis proportion of HT29 cells. After the drug treatment for 6, 24, and 48 hours, the apoptosis rate of oxaliplatin alone group was (9.76±0.47)%, (20.45±0.74)%, (28.70±3.29)%, and apoptotic rate of the combination group was (20.63±0.69)%, (34.35±1.02)%, (49.47±3.04)%, respectively, which was significantly higher as compared to oxaliplatin alone (P<0.01). Both oxaliplatin alone and combination therapy down-regulated expressions of procaspase-3, 9, and PARP protein. Procaspase-3, 9, PARP protein expression in combination group decreased more significantly, while procaspase-8 expression was not significantly different between the two groups. CONCLUSION: LCP can enhance the ability of oxaliplatin to inhibit cell proliferation and induce apoptosis, which may be associated with the activation of mitochondrial apoptosis pathway.

[Hepatectomy combined with cryoablation and ethanol injection for unresectable multiple liver metastases from colorectal cancer].

OBJECTIVE: To evaluate the efficacy and safety of hepatectomy combined with cryoablation and ethanol injection in patients with unresectable multiple liver metastases from colorectal cancer. METHODS: Clinical data of 23 patients with multiple liver metastases form colorectal cancer in the Affiliated Tumor Hospital of Guangzhou Medical College between January 2005 and December 2010 were analyzed retrospectively. There were 15 males and 8 females with average age of 52.2 years. All the patients underwent hepatectomy combined with ultrasound-guided cryoablation and ethanol injection intraoperatively. RESULTS: Among 98 lesions in 23 patients, 45 were removed intraoperatively and 53 were treated by cryoablation and ethanol injection. Operative time for liver lesions ranged from 27 to 96 minutes and intraoperative blood loss 50 to 450 ml. One patient developed pleural effusion and 1 myoglobinuria after operation. All the patients were followed up with a median follow-up time of 34 months(8 to 70 months). The 1-, 3-, and 5-year survival rates were 83.2%, 45.5% and 37.6% respectively. CONCLUSION: Hepatectomy combined with cryoablation and ethanol injection is an effective and safe treatment option for patients with unresectable multiple liver metastases from colorectal cancer.

Inhibitory effect of modified citrus pectin on liver metastases in a mouse colon cancer model.

AIM: To discuss the expression of glactin-3 in liver metastasis of colon cancer and its inhibition by modified citrus pectin (MCP) in mice. METHODS: Seventy-five Balb/c mice were randomly divided into negative control group (n = 15), positive control group (n = 15), low MCP concentration group (n = 15), middle MCP concentration group (n = 15) and high MCP concentration group (n = 15). CT26 colon cancer cells were injected into the subcapsule of mouse spleen in positive control group, low, middle and high MCP concentrations groups, except in negative control, to set up a colon cancer liver metastasis model. The concentration of MCP in drinking water was 0.0%, 0.0%, 1.0%, 2.5% and 5.0% (wt/vol), respectively. Liver metastasis of colon cancer was observed after 3 wk. Enzyme-linked immunosorbent assay (ELISA) was used to detect the concentration of galectin-3 in serum. Expression of galectin-3 in liver metastasis was detected by immunohistochemistry. RESULTS: Except for the negative group, the percentage of liver metastasis in the other 4 groups was 100%, 80%, 73.3% and 60%, respectively. The number of liver metastases in high MCP concentration group was significantly less than that in positive control group (P = 0.008). Except for the negative group, the median volume of implanted spleen tumor in the other 4 groups was 1.51 cm(3), 0.93 cm(3), 0.77 cm(3) and 0.70 cm(3), respectively. The volume of implanted tumor in middle and high MCP concentration groups was significantly smaller than that in positive control group (P = 0.019; P = 0.003). The concentration of serum galectin-3 in positive control and MCP treatment groups was significantly higher than that in the negative control group. However, there was no significant difference between them. Except for the negative control group, the expression of galectin-3 in liver metastases of the other 4 groups showed no significant difference. CONCLUSION: Expression of galetin-3 increases significantly in liver metastasis of colon cancer, which can be effectively inhibited by MCP.

Correlation between CD105 expression and postoperative recurrence and metastasis of hepatocellular carcinoma.

BACKGROUND: Angiogenesis is one of the mechanisms most critical to the postoperative recurrence and metastasis of hepatocellular carcinoma (HCC). Thus, finding the molecular markers associated with angiogenesis may help identify patients at increased risk for recurrence and metastasis of HCC. This study was designed to investigate whether CD105 or CD34 could serve as a valid prognostic marker in patients with HCC by determining if there is a correlation between CD105 or CD34 expression and postoperative recurrence or metastasis. METHODS: Immunohistochemical staining for the CD105, CD34 and vascular endothelial growth factor (VEGF) antibodies was performed in 113 HCC tissue specimens containing paracarcinomatous tissue and in 14 normal liver tissue specimens. The quantitation of microvessels identified by anti-CD105 and anti-CD34 monoclonal antibodies and the semiquantitation of VEGF expression identified by anti-VEGF monoclonal antibody were analyzed in conjunction with the clinicopathological characteristics of the HCC and any available follow-up information about the patients from whom the specimens were obtained. RESULTS: CD105 was not expressed in the vascular endothelial cells of any normal liver tissue or paracarcinomatous liver tissue but was expressed in the vascular endothelial cells of all HCC tissue. In contrast, CD34 was expressed in the vascular endothelial cells of normal liver tissue, paracarcinomatous tissue, and HCC tissue in the following proportions of specimens: 86.7%, 93.8%, and 100%, respectively. The microvascular densities (MVDs) of HCC determined by using an anti-CD105 mAb (CD105-MVD) and an anti-CD34 mAb (CD34-MVD), were 71.7 +/- 8.3 (SD) and 106.3 +/- 10.4 (SD), respectively. There was a significant correlation between CD105-MVD and CD34-MVD (r = 0.248, P = 0.021). Although CD34-MVD was significantly correlated with VEGF expression (r = 0.243, P = 0.024), CD105-MVD was more closely correlated (r = 0.300, P= 0.005). The correlation between microscopic venous invasion and CD105-MVD, but not CD34-MVD, was also statistically significant (r = 0.254, P = 0.018). Univariate analysis showed that CD105-MVD was significantly correlated with the 2-year overall survival rate (P = 0.014); CD34-MVD was not (P = 0.601). Multivariate analysis confirmed that CD105-MVD was an independent prognostic factor and that CD34-MVD was not. CONCLUSION: The anti-CD105 mAb is an ideal instrument to quantify new microvessels in HCC as compared with anti-CD34 mAb. CD105-MVD as compared with CD34-MVD is relevant a significant and independent prognostic indicator for recurrence and metastasis in HCC patients.

Expression of hypoxia-inducible factor 1alpha and vascular endothelial growth factor in hepatocellular carcinoma: Impact on neovascularization and survival.

AIM: To study the expression of hypoxia-inducible factor 1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) in hepatocellular carcinoma (HCC) and the impact on neovascularization and survival. METHODS: Expressions of HIF-1alpha, VEGF and microvessel density (MVD) are studied through immunohistochemistry in 36 cases of HCC and the corresponding paraneoplastic tissue and 6 cases of normal liver tissue. The relationship of the expressions of HIF-1alpha and VEGF with the clinicopathological data and survival are analyzed. RESULTS: The positive rate of VEGF in HCC was 32/36, which is significantly higher than that in paraneoplastic tissue and normal liver tissue (P<0.05). The expression of HIF-1alpha in HCC tissue is 24/36, also higher than that in paraneoplastic tissue and normal liver tissue (P<0.05). The expression of VEGF and HIF-1alpha in HCC with microscopic venous invasion is significantly higher than that in HCC without microscopic venous invasion (P<0.05). Spearman correlation analysis does not only show the expression of HIF-1alpha as correlated with the expression of VEGF (r(s) = 0.459, P<0.01), but it also shows the expression of HIF-1alpha and VEGF as correlated with MVD (r(s) = 0.412 and 0.336, respectively, P<0.05). The differences of the survival rates among VEGF positive group and VEGF negative group are significant (P<0.05), whereas the differences of the survival rates among the HIF-1alpha negative group and positive group are not significant (P>0.05). CONCLUSION: HIF-1alpha plays important roles in neovascularization in HCC possibly through regulation of VEGF transcription.

ADAM17 mRNA expression and pathological features of hepatocellular carcinoma.

AIM: To study the expression of a disintegrin and metalloproteinase 17 (ADAM17) mRNA in hepatocellular carcinoma (HCC) and to evaluate the relationship between ADAM17 mRNA expression and clinicopathological features of HCC. METHODS: Hepatocellular carcinomas (HCC) from 31 cases were divided into small HCC (SHCC), nodular HCC (NHCC) and solitary large HCC (SLHCC) according to tumor diameter and the number of nodes. ADAM17 mRNA expressions were compared among those groups by means of semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). The relationship between ADAM17 mRNA expression level and clinicopathological features of HCC was evaluated. RESULTS: NHCC had lower differentiation and was more frequently of microvascular invasion (10/12) than SHCC (3/11) and SLHCC (3/8) (P<0.05), but no statistical difference was observed between SHCC and SLHCC comparing their clinicopathological features. ADAM17 mRNA expression was detected in 77.4% (24/31) of HCC tissues and was significantly higher than that in paired non-cancerous liver tissues in which only 35.5% (11/31) of the samples were detected of the expression (P<0.05). The expression of ADAM17 mRNA was much higher in NHCC than in SHCC and SLHCC (P<0.05), while no significant difference was discovered between SHCC and SLHCC. The quantities of ADAM17 mRNA were significantly higher in poorly differentiated HCC than in well or moderately differentiated HCC, but no statistical difference was found concerning liver cirrhosis, tumor capsule formation or microvascular invasion of the cancer. CONCLUSION: The increased expression of ADAM17 may play a key role in the development of HCC. The expression levels of ADAM17 mRNA varied among different pathological types of HCC. Lower mRNA expression of ADAM17 mRNA in SLHCC may be associated with the better molecular pathological features of SLHCC.

[Overexpression of the RhoC gene correlates with invasion and metastasis of hepatocellular carcinoma].

OBJECTIVE: Rho, a ras homologous gene, encodes a group of GTP-binding proteins. Our previous study suggested that one member of the Rho gene family, RhoC, was related to the progression of human hepatocellular carcinoma (HCC). This study is to elucidate correlation of Rho overexpression with invasion and metastasis of HCC. METHODS: The expression level of RhoC mRNA and protein in 25 cases of HCC and adjacent non-cancerous liver tissue was examined by RT-PCR and Western blot. Mutation of RhoC gene was examined by PCR-SSCP. RESULTS: The expression of RhoC mRNA and protein was found in all HCC and adjacent non-cancerous liver tissue. The expression level of RhoC mRNA and protein was significantly higher in tumor tissue than in adjacent non-cancerous liver tissue (1.8 +/- 1.1 vs 1.0 +/- 0.7; 33 992 +/- 10 384 vs 17 342 +/- 9998, P < 0.01). The degree of RhoC overexpression was even more marked in metastatic lesions than in primary tumors (P < 0.01). Overexpression of the rhoC gene was significantly correlated with such clinic-pathological findings as cell differentiation, portal vein invasion, number of primary tumor nodules and metastatic lesions (P < 0.05). Mutation of RhoC gene was found in none of the HCC specimens examined. CONCLUSION: Overexpression of RhoC gene may play an important role in carcinogenesis and progression of HCC.

Effects of PI3K and p42/p44 MAPK on overexpression of vascular endothelial growth factor in hepatocellular carcinoma.

AIM: To study the relationship between hypoxia or epidermal growth factor (EGF) and the overexpression of vascular endothelial growth factor (VEGF) in hepatocellular carcinoma (HCC) and the signal transduction pathway of the transcription of VEGF in hepatoma cells. METHODS: Cobalt chloride and recombinant human EGF were used to stimulate the hepatoma cell lines HepG(2). VEGF mRNA was detected by using of semi-quantitative polymerase chain reaction (RT-PCR). Specific inhibitors of phosphatidylinositol 3-kinase (PI3K) and p42/p44 mitogen activated protein kinase (MAPK) were used to observe the effects of the two kinases on the regulation of the transcription of VEGF in hepatoma cells. RESULTS: The expression of VEGF mRNA in HepG(2) cells cultured in serum-free medium was 0.117. However, 100 mumol/L cobalt chloride for 24 h increased the expression of VEGF mRNA and VEGF mRNA increased gradually with the increase of the concentration and duration of cobalt chloride. Also, 25 ng/mL recombinant human EGF stimulated the expression of VEGF in HepG(2) cells and the expression increased with the increase of EGF concentration. 5 mumol/L LY294002 inhibited the expression of VEGF stimulated by cobalt chloride or recombinant human EGF and the inhibition decreased step by step with increase of the concentration of LY294002. But even 20 mumol/L LY294002 could not completely block the expression of VEGF. In contrast, PD98059 had no inhibitory effects on the transcription of VEGF stimulated by cobalt chloride or recombinant human EGF. CONCLUSION: The overexpression of VEGF in HCC could be promoted by hypoxia and EGF expression in HCC. The signal transduction pathway of VEGF transcription in HepG(2) cells may be through PI3K pathway, but not through p42/p44 MAPK pathway.

Expression and significance of RhoC gene in hepatocellular carcinoma.

AIM: To investigate the expression of RhoC gene in hepatocellular carcinoma (HCC) and to evaluate the relationship between RhoC gene expression and invasion and metastasis of HCC. METHODS: mRNA expression level of RhoC gene was examined by reverse transcription-polymerase chain reaction (RT-PCR) in 25 cases of HCC and para-cancerous normal liver tissues. In addition, mutation of RhoC gene was examined by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP). RESULTS: The mRNA expression levels of RhoC in tumor tissues were significantly higher than those in para-cancerous normal liver tissues (1.8+/-1.1 vs 1.0+/-0.7, P<0.01). The metastatic lesions outside of liver also showed significantly higher RhoC mRNA levels than corresponding tumor tissues in liver (3.3+/-0.5 vs 2.0+/-0.7, P<0.01). There were significant associations between RhoC gene expression and certain clinical and pathological findings, including cell differentiation, vein invasion, number of tumor nodes and metastatic lesions. Mutation of RhoC gene was not found by PCR-SSCP. CONCLUSION: The RhoC gene may be related to malignant transformation and development of HCC and may play an important role in the invasion and metastasis of HCC by overexpression but not mutation.