Proliferating Cell Nuclear Antigen Labeling Index Research Articles

Effects of ursodeoxycholic acid on liver regeneration and Cyclin D1 expression in rats

Objective To investigate the effect of ursodeoxycholic acid(UDCA) on liver regeneration and Cyclin Dl expression in rats. Methods Male Wistar rats were randomly divided into two groups (re=32 in each group: the control group in which the rats were fed on standard diets, and the UDCA group in which rats were given 1% UDCA diets. Seven days later, 70% partial hepatectomy (PH) was performed. On the day 0,1,2 and 3 after PH, the rat liver regeneration and Cyclin Dl expression were examined. Results On the day 0, the PCNA was hardly expressed in all rats. On the day 1 after PH, the PC-NA labeling index reached a peak, and it was significantly higher in the UDCA group than in the control group (40.70±4.73 vs 33. 24 ± 5. 59, P 0.05). On day 1, 2 after PH, the expression of Cyclin Dl in the UDCA group was significantly higher than in the control group (P 0.05 ). Conclusion UDCA can promote liver regeneration, and increase the expression of Cyclin D1. Key words: Uraodeoxycholic acid; Liver regeneration; Cyclin D1

Ginsenosides promote proliferation of granulosa cells from chicken prehierarchical follicles through PKC activation and up‐regulated cyclin gene expression

The effect of GS (ginsenosides) on proliferation of chicken GCs (granulosa cells) from prehierarchical SYF (small yellow follicles) was evaluated, and involvement of the PKC (protein kinase C) signalling pathway as well as mRNA expression of cyclins and CDK (cyclin-dependent kinase) were investigated. Whole SYF or GCs isolated from SYF were cultured in Medium 199 supplemented with 0.5% FCS (fetal calf serum). After 16 h, the cells were challenged with GS alone or in combination with PKC inhibitor H7 or activator PMA (phorbol 12-myristate 13-acetate) for 24 h in serum-free medium. Results showed that in both whole follicles and pure GCs monolayer culture system, GS (0.1-10 microg/ml) significantly increased the number of GCs in SYF in a dose-dependent manner, and this stimulatory effect was inhibited by H7, but enhanced by PMA. Meanwhile, the PCNA-LI (proliferating cell nuclear antigen labelling index) of GCs displayed similar changes with the cell number. Mechanism of GS action was further evaluated in cultured GCs separated from SYF. Western blot analysis showed that 10 microg/ml GS increased PKC translocation from cytoplasm to the plasma membrane of the GCs to become the active state. This effect was blocked by H7. Furthermore, GS up-regulated the expression of cyclin D1/CDK6 and cyclin E/CDK2 mRNAs in GCs; however, inhibition of PKC with H7 attenuated this stimulatory effect. These results indicated that GS could stimulate proliferation of chicken GCs through activated PKC-involved up-regulation of cyclin D1/CDK6 and cyclin E/CDK2 genes, subsequently promoting development of the chicken prehierarchical follicles.

The Impact of the Intra-Abdominal Space on Liver Regeneration After a Partial Hepatectomy in Rats

Little is known about the relationship between intra-abdominal space and liver regeneration. The present study was experimentally designed to investigate the influence of the "occupied space" or the "loss of occupied space" on a regenerating liver. Experiment 1: Rats were randomly assigned to two groups: SO (space occupied) rats (n = 40); occupancy of intra-abdominal space followed by a two-thirds partial hepatectomy (PH) and control rats (n = 40); A PH alone. The rats in both groups were euthanized at 24, 48, 96, and 168 h after the operation. Computed tomography (CT) images were analyzed to evaluate the regenerating-direction and the shape of the regenerated remnant liver. The liver to body weight ratio and the proliferating cell nuclear antigen (PCNA) labeling index were measured at each time point. Experiment 2: A second laparotomy was performed at 168 h after the PH in both groups; occupier-removal for the SO rats and a sham operation for the control rats. The rats in both groups were euthanized at 24 and 168 h after the second operation. The liver to body weight ratio and PCNA labeling index were measured at each time point. Experiment 1: The remnant liver of the SO rats enlarged toward the dorsal and caudal side because liver regeneration toward the ventral side in the SO rats was inhibited with the occupier in the abdominal space at 96 h, and later, after the PH. CT images showed a statistically significant difference in the shape of the regenerated remnant liver between the control group and the SO group. The liver/body weight ratio was significantly decreased in the SO rats at 96 and 168 h after PH (P < 0.05). There was no significant difference between the groups in the PCNA labeling index. The SO rats showed a significant increase of the PCNA labeling of the inferior right lobe (10.6%) in comparison with the index of the superior right lobe (7.8%), which came in direct contact with the occupier, at 96 h after the operation (P < 0.05). The cell density of superior right lobe of the SO rats group was significantly higher than that of the control group at 168 h after operation (P < 0.05). Experiment 2: There was no statistically significant difference in the liver/body weight ratio at 168 hrs after the second operation between the groups. However, there was a statistically significant increase of the PCNA labeling index 24 h after the second operation in the occupier-removal rats in comparison with the control rats (P < 0.05). The occupied intra-abdominal space was therefore found to suppress liver regeneration after a partial hepatectomy, while the removal of such an occupied space stimulated the regeneration of the liver.

Proliferating cell nuclear antigen, p53 and micro vessel density: Grade II vs. Grade III astrocytoma

Histological classification and grading are prime procedures in the management of patients with astrocytoma, providing vital data for therapeutic decision making and prognostication. However, it has limitations in assessing biological tumor behavior. This can be overcome by using newer immunohistochemical techniques. This study was carried out to compare proliferative indices using proliferating cell nuclear antigen (PCNA), extent of p53 expression and micro vessel morphometric parameters in patients with low grade and anaplastic astrocytoma. Twenty-five patients, each of grade II and grade III astrocytoma were evaluated using monoclonal antibodies to PCNA, p53 protein and factor VIII related antigen. PCNA, p53-labeling indices were calculated along with micro vessel morphometric analysis using Biovis Image plus Software. Patients with grade III astrocytoma had higher PCNA and p53 labeling indices as compared with grade II astrocytoma (29.14 plus/minus 9.87% vs. 16.84 plus/minus 6.57%, p 0.001; 18.18 plus/minus 6.14% vs. 6.14 plus/minus 7.23%, p 0.001, respectively). Micro vessel percentage area of patients with grade III astrocytoma was also (4.26 plus/minus 3.70 vs. 1.05 plus/minus 0.56, p 0.001), higher along with other micro vessel morphometric parameters. Discordance between histology and one or more IHC parameters was seen in 5/25 (20%) of patients with grade III astrocytoma and 9/25 (36%) of patients with grade II disease. PCNA and p53 labeling indices were positively correlated with Pearson's correlation, p less than 0.001 for both). Increased proliferative fraction, genetic alterations and neovascularization mark biological aggressiveness in astrocytoma. Immunohistochemical evaluation scores over meet the challenge of accurate prognostication of this potentially fatal malignancy.

Chemoprevention of oral cancer in animal models, and effect on leukoplakias in human patients with ZengShengPing, a mixture of medicinal herbs

ZengShengPing (ZSP), a mixture of six medicinal herbs, has been reported to prevent esophageal squamous cell carcinoma (SCC) in human patients with dysplasia. This study was designed to investigate the chemopreventive effects of ZSP on oral cancer in animal models and human patients. In the 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster cheek pouch model, ZSP (6g/kgBW/day by gavage for 10 weeks) significantly reduced the number of visible tumor, the tumor volume, and the incidence of SCC (P<0.01). Two biomarkers associated with cell proliferation, silver stained nucleolar organizer region (AgNOR) and proliferating cell nuclear antigen (PCNA)-labeling index, were also significantly suppressed by ZSP treatment (P<0.01). In the 4-nitroquinoline 1-oxide (4NQO)-induced oro-esophageal cancer model in mice, ZSP (10% in diet) also significantly reduced the incidence of tongue SCC from 55.2% (16/29) to 22.2% (6/27) (P<0.05), and slightly reduced the incidence of esophageal SCC from 34.5% (10/29) to 22.2% (6/27). Furthermore, in a randomized clinical trial on patients with oral leukoplakia, ZSP (4 tablets, 3 times per day for 8-12months) reduced the size of oral lesion in 67.8% (40/59) patients, whereas the placebo was effective in 17% (9/53) patients (P<0.01). Such an effect was associated with significant decrease of AgNOR and PCNA-labeling index. In summary, our studies have demonstrated the chemopreventive effects of ZSP on two animal models of oral cancer, and human patients with oral leukoplakia.

Effects of lycopene, synbiotic and their association on early biomarkers of rat colon carcinogenesis

This study evaluated whether a synergy exists for the combined treatment with lycopene and synbiotic on early biomarkers of colon carcinogenesis. Male Wistar rats received a diet containing 300mg/kg of lycopene and/or synbiotic (Bifidobacterium lactisplus oligofructose/inulin) or their combination 2weeks before and during carcinogen treatment with 1,2-dimethylhydrazine (DMH). Twenty-four hours after the last DMH application, the colons were processed for immunohistochemical analysis of proliferating cell nuclear antigen (PCNA), p53 protein, hematoxylin–eosin staining for apoptosis analysis and genotoxicity of fecal water by comet assay. Eight weeks after the last DMH application, the colons were analyzed for development of classical aberrant crypt foci (ACF) and mucin-negative ACF. Treatment with lycopene, synbiotic or their combination significantly increased apoptosis, reduced the PCNA and p53 labeling indexes and the development of classical ACF and mucin-negative ACF. Furthermore, a lower genotoxicity of fecal water was also detected in the groups treated with the chemopreventive agents. An additive/synergistic effect of the combined treatment with lycopene/synbiotic was observed only for the fecal water genotoxicity and mucin-negative ACF parameters. These results indicate that an additive/synergistic of the combination of chemopreventive agents on the initiation phase of colon carcinogenesis can be detected using selective early biomarkers.

Expression of Ki-67, PCNA, and p27kip1 in canine pituitary corticotroph adenomas

Pituitary-dependent hypercortisolism (PDH), which is caused by adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas, is a common endocrinopathy in dogs. Dogs with non-enlarged pituitaries harboring a microadenoma have a better prognosis than those with enlarged pituitaries. The aim of this study was to investigate the expression of the proliferation markers Ki-67 and proliferating cell nuclear antigen (PCNA) and the cell-cycle inhibitor p27kip1 in corticotroph adenomas in enlarged and non-enlarged pituitaries. The expression of Ki-67, PCNA, and p27kip1 was analyzed by immunohistochemical staining of 17 pituitary adenoma samples harvested during pituitary surgery in dogs with PDH. The labeling index was calculated by counting the number of immunopositive cells per 1,000 cells. The mean (± standard deviation) labeling index for Ki-67 was 8.4% ± 14.2% for the group with enlarged pituitaries, and 8.8% ± 5.5% for the group with non-enlarged pituitaries; that for PCNA was 35.5% ± 12.2% and 37.0% ± 15.5%; and that for p27kip1 was 29.3% ± 22.6% and 42.5% ± 27.9%, respectively. No significant differences in Ki-67, PCNA, and p27kip1 labeling indices were found between enlarged and non-enlarged pituitaries. However, a trend toward significance was observed when comparing the expression of p27kip1 in enlarged pituitaries versus normal pituitary tissue. It is concluded that Ki-67 and PCNA are not useful as proliferative markers for studying the pathobiology of pituitary corticotroph adenomas in dogs.

Correlation between MR diffusion weighted imaging with malignant degree of rabbit liver VX2 tumor models

To investigate the correlation between MR diffusion weighted imaging with cellularity and PCNA-LI of rabbit liver VX2 tumor models in different periods. 38 successful implanted rabbits were assigned randomly into 2 equal groups and were performed MR DWI in different periods (14 and 21 d) after implantation respectively. Specimens of all tumors were stained with HE and PCNA-LI after MR examination. (1) The ADC value (x 10(-3) mm2/s) in surrounding solid components of liver VX2 tumors in the group of 21 d was lower than that of the group of 14 d (0.77 +/- 0.19 vs 1.00 +/- 0.24, P = 0.007); (2) the cellularity and PCNA-LI in surrounding solid components of liver VX2 tumors in the group of 21 d were higher than those of the group of 14 d respectively (63% +/- 7% vs 43% +/- 10%, P = 0.011; 80% +/- 11% vs 56% +/- 8%, P = 0.008); (3) there were negative correlation between ADC value and cellularity, PCNA-LI of the solid components of the tumors (r = - 0.695, P = 0.000; r = -0. 698, P = 0.000). The cellularity may be the most important factor that affects ADC value in solid components of liver VX2 tumors. Since the degree of malignancy is closely connected with cellularity and PCNA labeling index, ADC value measurement may be a new method which could predict the degree of malignancies in vivo.

Low‐dose simultaneous delivery of adenovirus encoding hepatocyte growth factor and vascular endothelial growth factor in dogs enhances liver proliferation without systemic growth factor elevation

Hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) gene transfer proved to enhance liver regeneration. However, elevation of their plasma levels may induce potentially serious distant effects such as tumorigenesis or proliferative retinopathy. This study was performed to examine whether simultaneous administration of low-dose adenovirus encoding HGF and VEGF genes in dogs will stimulate liver proliferation but without inducing liver toxicity or systemic elevation of HGF and VEGF levels. Adult dogs received an intravenous injection of low-dose adenoviral vectors encoding human HGF and VEGF (HGF/VEGF), beta-galactosidase (lacZ) or phosphate-buffered saline (PBS). Liver proliferation was measured using the proliferating cell nuclear antigen (PCNA) immunostaining labelling index. HGF and VEGF plasma concentrations and transaminases were repeatedly measured. Transgene expression was evaluated using reverse-transcription polymerase chain reaction. Human HGF and VEGF expressions were detected only in the liver of HGF/VEGF dogs at day 2 after injection but declined at sacrifice (day 7). No expression was detected in the liver of the lacZ or PBS groups. Plasma levels of HGF and VEGF were not statistically different from those in the lacZ group (P=0.81, P=0.22 respectively). The PCNA labelling index was five-fold higher in the HGF/VEGF group compared with the lacZ group (P<0.01). No immunostaining was detected in the PBS group. Transaminases were only elevated (P<0.01) in the lacZ group compared with the other groups. We showed that simultaneous administration of low-dose adenoviral vectors encoding human HGF and VEGF genes can induce transgene expression and liver proliferation without liver toxicity or systemic growth factor elevation.

Increased expression of focal adhesion kinase correlates with cellular proliferation and apoptosis during 4‐nitroquinoline‐1‐oxide‐induced rat tongue carcinogenesis

Oral carcinogenesis is a multistep process and requires accumulation and interplay of a series of molecular genetic events. Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase that plays an important role in signalling pathways that are initiated at sites of integrin-mediated cell adhesions and by growth factor receptors. Overexpression of FAK has been linked to oral squamous cell carcinoma (OSCC). So, it is hypothesized that FAK expression might contribute to oral carcinogenesis. During 4-nitroquinoline-1-oxide-induced rat tongue carcinogenesis, FAK protein expression, proliferating cell nuclear antigen (PCNA) and apoptotic nuclei (TUNEL assay) were examined by means of immunohistochemistry. Along with the progress of multistage carcinogenesis, FAK expression increased significantly among different histopathological groups with normal mucosa, mild-dysplastic epithelia, moderate-dysplastic epithelia, severe-dysplastic epithelia and in turn OSCC. Furthermore, FAK immunohistochemical index and PCNA-labelling index displayed positive correlation (r = 0.946, P < 0.05), while negative associations were revealed between apoptotic index and final FAK index (r = -0.959, P < 0.05). Our results implicated a role for FAK in oral carcinogenesis. Inhibition of FAK might be a potential novel treatment strategy in this disease.

Diffusion‐weighted imaging of prostate cancer: Correlation between apparent diffusion coefficient values and tumor proliferation

To investigate whether the apparent diffusion coefficient (ADC) values of prostate cancer (PCa) are able to reflect tumor proliferation. The clinical and pathological information for 38 patients with PCa and 33 patients with benign prostate hyperplasia (BPH) were studied. Examination of the patients was performed using a 1.5 T superconducting magnetic scanner equipped with a pelvic phased-array multicoil. Diffusion-weighted images (DWIs) were acquired using an echo-planar imaging sequence. The ADC values of PCa, BPH, and peripheral zone (PZ) were calculated. The cellularity of PCa was recorded based on hematoxylin and eosin staining. The proliferating cell nuclear antigen (PCNA) was detected using an immunohistochemical technique. The ADC values of PCa, BPH, and PZ were 49.32 +/- 12.68 x 10(-5) mm(2)/s, 86.73 +/- 26.75 x 10(-5) mm(2)/s, and 126.25 +/- 27.21 x 10(-5) mm(2)/s, respectively. The ADC values of PCa were lower than those of BPH and PZ (P < 0.05). The cellularity and PCNA labeling index (LI) of PCa were higher than those of BPH (P < 0.05). The ADC values of PCa were negatively correlated with those of cellularity and PCNA LI (r = -0.646 and -0.446, respectively; P < 0.05). The ADC values of PCa can reveal the differences in proliferative activity between PCa and BPH. These values are therefore able to predict the proliferative rate of variously differentiated prostate cancers.

Regeneration of Graft Livers and Limited Contribution of Extrahepatic Cells After Partial Liver Transplantation in Humans

Background Liver regeneration is still not fully understood. Partial liver transplantation (LT) can provide the opportunity to investigate the mechanisms of liver regeneration, including the contribution of extrahepatic cells to liver regeneration. Methods Of 61 patients transplanted with partial liver graft between August 1997 and October 2006, 56 patients were studied, including 49 adults and 7 children. Sequential computed tomography volumetric analysis was performed for volume measurement, while proliferating cell nuclear antigen (PCNA) labeling index was investigated for liver cell proliferation in nonprotocol liver biopsy specimens. In addition, 15 male recipients who had female liver grafts were investigated in order to detect Y chromosomes as extrahepatic cells in nonprotocol liver biopsy specimens. Results Graft volume per standard liver volume was markedly increased after adult-to-adult living-donor (LD) LT. In pediatric transplants, there was no volume increase over time. PCNA labeling index was vigorous in adult-to-adult LDLT in the early period after LDLT. No Y chromosome was evident in hepatocytes from female-donor male-recipient grafts during or after liver regeneration. However, in the cases of failing grafts of this type, many Y-chromosome-positive cells were observed in the graft liver. The character of those cells was CD34(−), CK9(−), hepatocyte-specific antigen(−), and CD68(+/−). Conclusion In adult-to-adult LDLT, vigorous liver regeneration occurs in the graft liver, demonstrated by not only volumetric but cell kinetic analysis. Involvement of extrahepatic cells in normal liver regeneration seems limited.

Effects of Bicyclol on Liver Regeneration After Partial Hepatectomy in Rats

Bicyclol is a synthetic antihepatitis drug with antioxidative property. The present study was performed to investigate the effect of bicyclol on liver regeneration after partial hepatectomy in rats. Bicyclol (300 mg/kg) was given to rats subjected to 70% hepatectomy three times before operation. At 6, 24, and 48 h after resection, samples were collected for the measurement of serum alanine aminotransferase (ALT), total bilirubin (TBil), hepatic glycogen, malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH). Moreover, liver regeneration rate, proliferating cell nuclear antigen (PCNA) labeling, proliferation index, and histopathological examination were evaluated at 48 h after hepatectomy. As a result, bicyclol significantly increased regeneration rate, mitotic index (MI), PCNA labeling index, and proliferation index in PH rats. Additionally, bicyclol remarkably inhibited the elevation of serum ALT and TBil levels, alleviated the formation of liver MDA, restored impaired antioxidant SOD and GSH, increased hepatic glycogen content, and also attenuated hepatic vacuolar degeneration. These results suggested that bicyclol had a beneficial effect on liver regenerative capacity of the remnant liver tissue after hepatectomy, probably due to its antioxidative property.

Prognostic value of the apoptotic index analysed jointly with selected cell cycle regulators and proliferation markers in non-small cell lung cancer

In a previous small series of surgically treated non-small cell lung cancer patients (NSCLC), we found that higher apoptotic index (AI) negatively influenced survival (Dworakowska D, Jassem E, Jassem J, Karmolinski A, Dworakowski R, Wirth T, et al. Clinical significance of apoptotic index in non-small cell lung cancer: correlation with p53, mdm2, pRb and p21WAF1/CIP1 protein expression. J Cancer Res Clin Oncol 2005; 131:617–623.). In this study we attempted to verify our previous finding in larger group of 170 NSCLC cases, additionally correlating AI to selected cell cycle regulators as well as a proliferation marker. Apoptosis was assessed with the use of the TUNEL technique, whereas the expression of p53, pRb, mdm2, p21 WAF1/CIP1, cyclin D1 and PCNA were assessed immunohistochemically. The mean and the median AI was 12 and 8, respectively. The expression of p53, pRb, mdm2, p21 WAF1/CIP1 proteins and cyclin D1 was found in 47%, 71%, 37%, 65% and 40% of cases, respectively. The mean and the median PCNA labeling index (PCNA LI) was 34 and 35, respectively. AI was not correlated with any patient characteristic or other tumor markers. In uni- and multivariate analysis AI, analysed separately or jointly with cell cycle regulators and PCNA LI, did not influence disease-free or over-all survival. However, patients with “very high AI/very high PCNA LI” had a particularly poor prognosis ( P = 0.001). Patients with “very low AI/negative pRb” phenotype survived for a shorter time in comparison to others ( P = 0.04). In addition, patients with the highest PCNA LI had a worse outcome in comparison to patients with the lowest PCNA LI ( P = 0.04), especially those with concomitant p53 protein expression ( P = 0.026) or lacking pRb protein expression ( P = 0.04). This study demonstrates that joint analysis of several factors involved in apoptosis, proliferation and cell cycle regulation, but not AI alone, might provide additional prognostic information in NSCLC patients.

Targeting calcium/calmodulin-dependence kinase I and II as a potential anti-proliferation remedy for endometrial carcinomas

Calcium/calmodulin-dependent kinase (CaMK) I and II expression in endometrial cancer cells correlates with the malignant potential of this tumor, and CaMKI and II are potential therapeutic targets in endometrial cancer. CaMKI and II expression was significantly associated with PCNA-labeling index, clinical stage, histological grade, the presence of invasion to greater than one-half the myometrium, and clinical outcome. All endometrial cancer cell lines examined were sensitive to the growth-inhibitory effect of KN-93, a membrane-permeant CaMKs-selective inhibitor that is competitive with calmodulin. KN-93 induced the G0/G1 arrest and apoptosis, rising hopes that KN-93 may become a useful treatment for endometrial cancers.

Long-term effect of Spirulina platensis extract on DMBA-induced hamster buccal pouch carcinogenesis (immunohistochemical study)

In cancer research, the use of complementary and alternative medicine has increased over the past decade. In this study, 80 male golden Syrian hamsters were divided into four equal groups; the right buccal pouches of the hamster rats in group 1 were painted with 0.5% solution of 7, 12-dimethylbenz[a]anthracene (DMBA), three times a week for 32 weeks. The same pouches of group 2 were subjected to the same DMBA painting; but at the same time, the animals received 10 mg/daily Spirulina platensis extract for the same period. In group 3, the same regimen of DMBA painting was done but for 24 weeks only and the daily systemically S. platensis was received for the 32 weeks. In group 4, neither DMBA painting nor S. platensis administration was done but pouches were painted with saline and served as a control one. Five rats from each group were sacrificed at 12, 24, 28, and 32 weeks, respectively. The required pouches were excised, fixed, and embedded in paraffin to be immunostained with proliferating cell nuclear antigen (PCNA). The results showed that increased PCNA expression was directly related to the severity of pathological alterations from normal epithelium to dysplasia and from dysplasia to squamous cell carcinoma (SCC) in the study groups at the different extended periods of DMBA application and S. platensis extract administration. Analysis of variance and Duncan's multiple-range test for PCNA labeling index were proved a high significant difference (P < 0.01) between the different groups. From the previous results, it can be concluded that S. platensis extract has a beneficial role in regression of cancer progression.

CXCR‐4 knockdown by small interfering RNA inhibits cell proliferation and invasion of oral squamous cell carcinoma cells

Oral squamous cell carcinomas (OSCCs) are characterized by a high degree of local invasion and a high rate of metastases to cervical lymph nodes. Downregulation of CXCR-4 by siRNA inhibits invasion and growth of breast and colon cancer cells. However, there have been no reports on the downregulation of CXCR-4 by small interfering RNA (siRNA) in oral cancer cells. We generated two stable CXCR-4-knockdown clones (KBsi and KOSCC-25Bsi) from the KB and KOSCC-25B OSCC cell lines by lentiviral delivery. In vitro invasion and cell proliferation assays were used to investigate the effect of CXCR-4 downregulation on cell proliferation and invasiveness in KBsi and KOSCC-25Bsi. Immunohistochemistry was performed to evaluate the correlation between CXCR-4 expression and proliferation in 26 OSCC tissue samples. CXCR4-knockdown OSCC cells showed reduced invasiveness. The invasiveness of KBsi decreased to 29.5% of the vector-infected controls, and KOSCC-25Bsi decreased to 38.1% of the control vector-infected cells (P < 0.05). The CXCR4-knockdown OSCC cells grew significantly slower than the vector-infected control cells. KBsi and KOSCC-25Bsi cells proliferated at 69.5% and 71.7%, respectively, of the rate of control vector-infected cells (P < 0.05). CXCR-4-positive group had significantly higher PCNA labeling index than CXCR-4-negative group in OSCC tissue samples. These results suggest that the downregulation of CXCR-4 induces anti-proliferative and anti-invasive effects in OSCC and that CXCR-4 might be a useful target molecule for the treatment of OSCC.

Synergistic use of epidermal growth factor and 5-fluorouracil for the treatment of human colorectal cancer in BALB/C nude mice subcutaneous xenograft model

To investigate the synergistic effect of epidermal growth factor(EGF) and 5-fluorouracil for the treatment of human colorectal cancer in BALB/C nude mice subcutaneous xenografts model. Human colorectal cancer Caco-2 cells were transplanted into the subcutaneous tissue of nude mice. The tumor growth was followed up every 4 days after treatment, and estimated tumor weight, tumor growth curve, and results from histologic examination were used to evaluate the effects of EGF on the growth of tumors. Proliferation of the tumor cells was estimated by PCNA labeling index. The combined use of EGF and 5-fluorouracil significantly inhibited the growth of colorectal cancer xenografts in nude mice with the inhibitory rate of 57.05% which was higher than 5-fluorouracil did (40.97%)(P<0.05). No pathologic changes were observed in organs. PCNA labeling index was elevated in combined group which implied more tumor cells reentry cell cycle. Epidermal growth factor, which may recruit colorectal cancer cells into activated phases of the cell cycle, can enhance the sensitivity of colorectal cancer cell Caco-2 to 5-fluorouracil.

Metalloproteinases 2 and -9 activity during promotion and progression stages of rat liver carcinogenesis

Activity of metalloproteinases 2 and 9 (MMP-2 and 9) during promotion and progression of rat liver carcinogenesis was investigated in a modified resistant hepatocyte model. Development of preneoplastic liver lesions positive for glutathione S-transferase 7-7-(GST-P 7-7-positive PNL) and tumors besides hepatocytes positive for proliferating cell nuclear antigen (PCNA) were quantified and compared to MMP-2 and-9 activity using gelatin zymography. Marked increases in GST-P 7-7-positive PNL development, PCNA labeling indices, MMP-2 (pro, intermediate and active forms) and pro-MMP-9 activity were observed after proliferative stimulus induced by 2-acetylaminofluorene (2-AAF) exposure cycles. After 2-AAF withdrawal, increase in MMP-2 activity was detected only in neoplastic mixed lesions, whereas active MMP-9 was increased in both PLN and neoplastic tissues. Our findings suggest that MMP-2 may be associated with proliferative events induced by 2-AAF rather than with selective growth of PNL and that MMP-9 could be associated with progression of PNL and neoplastic mixed lesions.

Dynamic contrast-enhanced magnetic resonance imaging for estimating tumor proliferation and microvessel density of oral squamous cell carcinomas

We evaluated the relationship between histopathological prognostic factors, tumor proliferation microvessel density (MVD), and enhancement parameters in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in oral squamous cell carcinoma (SCC). Twenty-eight T2 and T3 patients with primary oral SCC underwent DCE-MRI using three-dimensional fast imaging with a steady-state precession sequence. Tumor cell proliferation and MVD of all surgical specimens were evaluated using immunohistochemical staining with CD34 and the antibody for proliferating cell nuclear antigen (PCNA). Regression analysis was used to statistically analyze the relationship between the PCNA labeling index or MVD and each of three DCE-MRI parameters: maximum CI (CI-max), maximum CI gain (CI-gain) and the CI-gain / CI-max ratio). The PCNA labeling index and MVD showed significant correlations with the CI-gain/CI-max ratio (P=0.0012, r=0.581 and P=0.00141, r=0.574, respectively). The assessment of DCE-MRI parameters may prove to be a valuable non-invasive method for assessing tumor cell proliferation and MVD of patients with oral cancer.