[Association between vitamin D level and grip strength in adults aged 50 and older in Shanghai]

Objective: To understand the association between vitamin D level and grip strength in people aged ≥50 years in Shanghai. Methods: Data were obtained from the WHO's Study on Global Ageing and Adult Health in Shanghai during 2018-2019. Logistic regression model was used to analyze the association between vitamin D level and grip strength, and a stratified analysis was conducted for different gender, age and dairy product intake groups. Restricted cubic spline was used to evaluate the dose-response association between vitamin D level and low grip strength. Results: A total of 4 391 participants were included in the study, including 2 054 men (46.8%), with an average age of (67.02±8.81) years. And 1 421 individuals (32.4%) had low grip strength; 1 533 individuals (34.9%) had vitamin D deficiency, and 401 individuals (9.1%) had vitamin D deficiency. After adjusted for confounding factors, the logistic regression results analysis showed that individuals with vitamin D deficiency had a higher risk for low grip strength (OR=1.41, 95%CI: 1.09-1.83). In men, after adjusting for confounding factors, vitamin D deficiency was positively associated with the risk for low grip strength (OR=1.67, 95%CI: 1.12-2.50), but there was no significant association between vitamin D level and grip strength in women (OR=1.30, 95%CI: 0.97-1.74). In age group 60-69 years and ≥80 years, there was significant association between vitamin D deficiency and low grip strength after adjusting for confounding factors (OR=1.57, 95%CI: 1.05-2.35; OR=2.40, 95%CI: 1.08-5.31). In people who had daily intake of dairy product <250 ml, there was positive association between vitamin D deficiency and low grip strength, but there was no significant association in people who had daily dairy product ≥250 ml after adjusting for confounding factors. The restrictive cubic spline demonstrated that risk of low grip strength might decreased with the increase of vitamin D levels, however, the difference was not significant (P>0.05). Conclusions: This study demonstrated that there is association between vitamin D level and grip strength. People with vitamin D deficiency have higher risk for low grip strength.

[Association between dietary pattern and frailty among people aged 50 years and over in Shanghai]

Objective: To investigate dietary patterns of individuals aged ≥50 in Shanghai and analyze their association with frailty. Methods: Using data from the third wave of the Study on Global Ageing and Adult Health in Shanghai conducted between 2018 and 2019. We collected the frequency and average intake of food by the food frequency questionnaire. Factor analysis was used to extract dietary patterns, and a frailty index was constructed using the ratio of the cumulative total score of health deficits to 35 health-related variables considered. We used an ordinal multinomial logistic regression model to analyze the association between dietary patterns and frailty. Results: A total of 3 274 participants aged (67.9±9.2) years were included in the study, including 1 971 (60.2%) men and 1 303 (39.8%) women. We extracted four dietary patterns: high-protein-nuts pattern, potato-bean-vegetable-fruit pattern, poultry-meat pattern, and high-oil-salt pattern. After adjusting for confounding factors, the logistic regression analysis showed that compared with the high-oil-salt pattern, the high-protein-nuts pattern was negatively associated with the risk of higher frailty (OR=0.743, 95%CI: 0.580-0.951). We did not find an association between dietary patterns and frailty between the different gender groups. In the age group 50-64, the high-protein-nuts and potato-bean-vegetable-fruit patterns were negatively correlated with a higher degree of frailty than the high-oil-salt pattern. In the low-level physical activity group, the high-protein-nuts pattern was negatively correlated with a higher degree of frailty than the high-oil-salt pattern (OR=0.509, 95%CI: 0.361-0.720). However, we found no significant effect of the high-protein nuts pattern, potato-bean-vegetable-fruit pattern, and poultry-meat pattern on the risk of higher frailty compared to the high-oil-salt pattern in the moderate to high level of physical activity group. Conclusions: Compared to the high-oil-salt pattern, dietary patterns with a higher intake of high-protein nuts, potatoes, legumes, and fruits and vegetables might be associated with a lower risk of higher frailty in residents aged 50-64 years of age than with a high oil and salt pattern. At the same time, it may have a more significant protective effect in people with lower physical activity levels. It is suggested that a diet rich in high-protein foods, nuts, potatoes, beans, vegetables, and fruits may help reduce and delay the risk of frailty.

[Frailty trajectories in people aged 50 years and above in China]

Objective: To identify distinct frailty trajectories in a cohort of nationwide community adults aged 50 years and above, and explore the relationship between frailty trajectories and their socioeconomic characteristics and behavioral factors at baseline survey. Methods: Data were from the three waves of "Global Ageing and Adult Health Research" (SAGE) by World Health Organization in China. The frailty index is generated from 32 items. Group-based trajectory modeling using a censored normal model was conducted to identify the patterns in frailty progression over time. Multinomial logistic regression model was used to examine the effect of socioeconomic status and behavioral factors on the frailty trajectories. Results: A total of 4 303 adults aged 50 years and above with complete data from all three rounds of project were included in the final analysis. Three frailty trajectories were identified: low and stable trajectory (LT) (56.8%), moderately increased trajectory (MT) (34.4%) and highly increased trajectory (HT) (8.8%). The results of the multinomial logistic regression analysis showed that the HT group was more likely to be women (OR=1.88, 95%CI:1.22-2.92) and rural residents (OR=1.87, 95%CI:1.29-2.70) compared with the LT group. In terms of household wealth per capita, there was a clear gradient in ORs, the people with lower household wealth were more likely to be classified in the HT group. Conclusion: This study identified three patterns of progression of frailty trajectories in population aged 50 years and above in China and highlighted that interventions should target those vulnerable populations with rapid progression of frailty.

Moxibustion Regulates Gastrointestinal Motility via HCN1 in Functional Dyspepsia Rats

Background

Moxibustion therapy has been found to ameliorate clinical symptoms of functional dyspepsia (FD). We aimed to examine the regulatory effect of moxibustion on the gastrointestinal (GI) motility in FD and explore the underlying mechanism based on the hyperpolarization-activated cyclic nucleotide-gated cation channel 1 (HCN1).

Material/Methods

Moxibustion therapy was used in FD rats induced by using classic tail-pinch and irregular feeding. Weight gain and food intake were recorded weekly, followed by detecting gastric residual rate (GRR) and small intestine propulsion rate (IPR). Next, western blotting was performed to determine the expression levels of HCN1 in the gastric antrum. qRT-PCR was used to detect HCN1 in the small intestine and hypothalamic satiety center. Double immunolabeling was used for HCN1 and ICCs in gastric antrum and small intestine.

Results

The obtained results suggested that moxibustion treatment could increase weight gain and food intake in FD rats. The GRR and IPR were compared among the groups, which showed that moxibustion treatment could decrease GRR and increase IPR. Moxibustion increased the expression of HCN1 in the gastric antrum, small intestine, and hypothalamic satiety center. Histologically, the co-expressions of HCN1 and ICCs tended to increase in gastric antrum and small intestine. Meanwhile, HCN channel inhibitor ZD7288 prevented the above-mentioned therapeutic effects of moxibustion.

Conclusions

The results of the present study suggest that moxibustion can effectively improve the GI motility of FD rats, which may be related to the upregulation of HCN1 expression in gastric antrum, small intestine, and satiety center.

Overexpression of the mitochondrial chaperone tumor necrosis factor receptor-associated protein 1 is associated with the poor prognosis of patients with colorectal cancer

Tumor necrosis factor receptor-associated protein-1 (TRAP-1), a mitochondrial chaperone, contributes significantly to the progression of cancer. However, the understanding of its involvement in the clinicopathological characteristics and prognosis of colorectal cancer (CRC) remains limited. The aim of the present study was to assess the significance of TRAP-1 expression in CRC. The expression of TRAP-1 was evaluated in corresponding cancerous, paracancerous, lymph node and distant metastatic tissues of 256 cases of CRC by immunohistochemistry. The associations between TRAP-1 expression and the clinicopathological parameters and survival rates of patients was assessed. Out of 256 patients with CRC, TRAP-1 expression was detected in 203 (79.3%). TRAP-1 expression was significantly increased in cancerous tissue compared with that in corresponding paracancerous tissues (P<0.001). Overexpression of TRAP-1 was significantly associated with differentiation (P=0.011), depth of invasion (P=0.006), lymph node metastasis (P<0.001) and tumor-node-metastasis stage (P<0.001). In patients with high TRAP-1 expression, the 5-year overall survival (OS) rate was 38.0%, in contrast to 56.5% in patients with low TRAP-1 expression (P=0.003). Similarly, the 5-year progression-free survival (PFS) was 26.6% for patients with high TRAP-1 expression and 53.3% for patients with low TRAP-1 expression (P<0.001). Multivariate analyses indicated the TRAP-1 expression is an independent prognostic factor for poorer OS [P=0.015; hazard ratio (HR), 1.914] and PFS (P<0.001; HR, 2.534). Thus, TRAP-1 may serve as a potential biomarker for predicting the prognosis of patients with CRC. Specifically, overexpression of TRAP-1 may predict progression and poor survival in cases of CRC.

Two variants on T2DM susceptible gene HHEX are associated with CRC risk in a Chinese population

Increasing amounts of evidence has demonstrated that T2DM (Type 2 Diabetes Mellitus) patients have increased susceptibility to CRC (colorectal cancer). As HHEX is a recognized susceptibility gene in T2DM, this work was focused on two SNPs in HHEX, rs1111875 and rs7923837, to study their association with CRC. T2DM patients without CRC (T2DM-only, n=300), T2DM with CRC (T2DM/CRC, n=135), cancer-free controls (Control, n=570), and CRC without T2DM (CRC-only, n=642) cases were enrolled. DNA samples were extracted from the peripheral blood leukocytes of the patients and sequenced by direct sequencing. The χ² test was used to compare categorical data. We found that in T2DM patients, rs1111875 but not the rs7923837 in HHEX gene was associated with the occurrence of CRC (p= 0.006). for rs1111875, TC/CC patients had an increased risk of CRC (p=0.019, OR=1.592, 95%CI=1.046-2.423). Moreover, our results also indicated that the two variants of HEEX gene could be risk factors for CRC in general population, independent on T2DM (p< 0.001 for rs1111875, p=0.001 for rs7923837). For rs1111875, increased risk of CRC was observed in TC or TC/CC than CC individuals (p<0.001, OR= 1.780, 95%CI= 1.385-2.287; p<0.001, OR= 1.695, 95%CI= 1.335-2.152). For rs7923837, increased CRC risk was observed in AG, GG, and AG/GG than AA individuals (p< 0.001, OR= 1.520, 95%CI= 1.200-1.924; p=0.036, OR= 1.739, 95%CI= 0.989-3.058; p< 0.001, OR= 1.540, 95%CI= 1.225-1.936). This finding highlights the potentially functional alteration with HHEX rs1111875 and rs7923837 polymorphisms may increase CRC susceptibility. Risk effects and the functional impact of these polymorphisms need further validation.

The soy-derived peptide Vglycin inhibits the growth of colon cancer cells in vitro and in vivo

Vglycin, a novel natural polypeptide isolated from pea seeds, possesses antidiabetic properties. Our previous studies have shown that Vglycin can induce the differentiation of human colon adenocarcinoma cells. We aimed to determine the anticancer activity of Vglycin against colon cancer cells and to elucidate related apoptosis-inducing mechanisms. Treatment with purified Vglycin significantly reduced growth, viability, and colony formation of CT-26, SW480, and NCL-H716 colon cancer cells in a dose-dependent manner while down-regulating the expression of proliferating cell nuclear antigen. Mouse xenograft studies showed a 38% inhibition of colon cancer growth in mice treated with Vglycin (20 mg/kg/day) at day 21. Furthermore, the potential mechanisms involved in Vglycin-induced cell apoptosis were examined using cell cycle studies, ultrastructural examination, as well as apoptosis-associated pathway analysis. The results showed that Vglycin significantly promoted apoptosis and G1/S phase cell cycle arrest. As revealed by Western blot, the expression of CDK2 and Cyclin D1 was down-regulated in all three Vglycin-treated colon cancer cells, indicating that the CDK2/Cyclin D1 cell cycle pathway involved in the initiation and progression of colon cancer. Moreover, the inhibition of Vglycin-induced cell proliferation in colon cancer cells was accompanied by alteration of the expression levels of the apoptosis-related proteins Bax, Bcl-2 and Mcl-1, and an increase of caspase-3 activity. Together, our results suggest that Vglycin may be another plant-derived peptide that suppresses colon cancer, supporting the continued investigation of Vglycin as therapeutic agent for colon cancer. Impact statement The antidiabetic properties and the capability of inducing differentiation of human colon adenocarcinoma cells of Vglycin have been reported in our previous studies. However, the anticancer potential of Vglycin on colon cancer cells and its possible related mechanisms were still unknown. In this study, we found that Vglycin could reduce growth, viability, and colony formation or colony size of CT-26, SW480, and NCL-H716 colon cancer cells. Moreover, Vglycin decreased tumor volume by 38% in xenograft mice transplanted with CT-26 cells. The mechanisms of these phenomena may be due to the down-regulated CDK2 and Cyclin D1, G1/S phase cell cycle arrest, and the dysregulated expression of Bax, Bcl-2, and Mcl-1. The findings highlight the anticancer potential of Vglycin against colon cancer cells, and suggest Vglycin may be another colon cancer potential suppressive component of plant-derived peptides.

Physiological behavior and quality of fresh ginseng stored in modified atmospheres generated by several package films

Physiological behaviors and quality attributes of fresh ginseng (Panax Ginseng) stored in modified atmospheres generated by several package films were investigated. The chemical compositions were also measured before and after storage. The respiration rates of fresh ginseng were inhibited effectively by film package, especially in package with lower gas permeability coefficient film. The polyphenol oxidase (PPO) activity reduced markedly and high Hunter L (*) value was maintained. Significant differences (p < 0.05) in firmness, weight loss, decay rate and pectin content were found between 0.10 mm packages and 0.05, 0.07 mm packages after 5 months of storage. The best quality parameters of fresh ginseng were obtained from the combination of 0 °C-0.10 mm. Significant difference (p < 0.05) in total saponin content was not found, and the highest total saponin content was also obtained from the combination of 0 °C-0.10 mm. The content of total sugar and reducing sugar increased significantly (p < 0.05), especially for package film with higher gas permeability coefficient. The storage life of fresh ginseng was extended significantly by film packages to 5 months with good quality and lower decay rate, especially for package film with low gas permeability coefficient.

Clinicopathological and prognostic significance of microRNA-107 in human non small cell lung cancer

BACKGROUND

MicroRNAs (miRNAs) are small, non-coding RNAs which can function as oncogenes or tumor suppressor genes in human cancers. Researchers have found that the expression level of miR-107 was decreased in human non-small cell lung cancer (NSCLC) tissues and cell lines, however, its clinicopathological and prognostic significance in NSCLC has not been investigated.

METHODS

Quantitative real-time PCR (qRT-PCR) was used to analyze the expression of miR-107 in 137 pairs of fresh NSCLC and matched adjacent normal tissue specimens. The chi-square test and Fishers exact tests were used to examine the associations between miR-107 expression and the clinicopathological characters. The overall survival (OS) and progression-free survival (PFS) were analyzed by log-rank test, and survival curves were plotted according to Kaplan-Meier.

RESULTS

The expression level of miR-107 was significantly lower in tumor tissues than that in corresponding noncancerous tissues (0.4676 ± 0.2078 vs. 1.000 ± 0.3953, P<0.001). Low expression of miR-107 was found to significantly correlate with TNM stage (p=0.001), regional lymph node involvement (p=0.04), and tumor differentiation (p=0.003). Kaplan-Meier analysis with the log-rank test indicated that low miR-107 expression had a significant impact on OS (35.2% vs. 69.3%; P=0.008) and PFS (30.0% vs. 56.2%; P=0.029). In a multivariate Cox model, we found that miR-107 expression was an independent poor prognostic factor for both 5-year OS (HR=2.57, 95% CI: 1.88-10.28; P=0.007) and 5-year PFS (HR=3.08, 95% CI: 2.01-8.92; P=0.003).

CONCLUSION

The expression of miR-107 was decreased in NSCLC. Low expression of miR-107 was significantly associated with tumor progression and decreased survival in patients with NSCLC, indicating that miR-107 may serve as a novel prognostic marker in NSCLC.

The meaning of life and health experience for the Chinese elderly with chronic illness: a qualitative study from positive health philosophy

Ageing and the concurrent prevalence of chronic disease in older adults produce a great burden and challenge for family, society and individuals. There is a definite need to build the science about caring for older Chinese adults from their perspective to inform health-care professionals. The aim of the study was to investigate the meaning of life and health experience of Chinese elderly with chronic illness and identify health potential from a positive perspective. A qualitative descriptive study was undertaken to interview 11 older adults ages 64-92 in a day centre. In 2011, the data were collected and analysed by thematic analysis. Four interrelated themes indicated a rich meaning of life and health experience from the older adults: (i) happiness lies in contentment; (ii) sense of responsibility; (iii) letting nature take its course; (iv) and proactive self-balance. These interrelated themes with partial conflict presented a dialectic meaning of life and were interpreted from traditional Chinese culture and compared with positive health philosophy. The significance of finding will encourage nursing practice work with clients and identify the potential and self-help strength of the elderly.

Inhibition of beta-amyloid precursor protein gene in SK-N-SH cells by piperlonguminine/dihydropiperlonguminine components separated from Chinese herbal medicine Futokadsura stem

Alzheimer disease (AD) is a progressive neurodegenerative disease characterized by progressive cognitive and memory decline. Amyloid precursor protein (APP) is a transmembrane protein, it has been known to play an important role in AD pathogenesis. Previous studies have shown that a Chinese herb Futokadsura stem can selectively inhibit the expression of amyloid precursor protein (APP) gene. We want to find the effective components in Futokadsura stem which have the inhibitory effect. Futokadsura stem was separated and purified with chemical methods, and then different separation components were added on SK-N-SH cells in different concentrations. Using MTT methods, we detected proliferation activity of SK-N-SH cells which were treated with different separation components of Futokadsura stem. Using RT-PCR, Western blot methods, we detected APP gene expression in SK-N-SH cells after they are treated with different Futokadsura stem separation components. We found that piperlonguminine/dihydropiperlonguminine components (1:0.8) separated from Futokadsura stem acetic ether extracts could selectively inhibit the expression of APP gene in SK-N-SH cells in mRNA and protein levels. This inhibition effect is concentration-dependent. Under experimental concentrations, the components did not affect the proliferation activity of SK-N-SH cells. These data suggest that piperlonguminine/dihydropiperlonguminine components are the effective components in Futokadsura stem which can inhibit the expression of APP gene.

Curcumin downregulates homeobox gene NKX3.1 in prostate cancer cell LNCaP

AIM

To elucidate the effect and the mechanisms of curcumin on the expression of the human homeobox gene NKX3.1 in the prostate cancer cell LNCaP.

METHODS

The expression change of NKX3.1 in cells incubated with varying concentrations of curcumin was observed by Western blotting and RT-PCR. A dual luciferase reporter assay was used to test the effect of curcumin on the activity of the NKX3.1 1040 bp promoter. Curcumin-treated cells disposed to a designated amount of androgen analog R1881 and the androgen receptor (AR) antagonist flutamide, then the expression of NKX3.1 or the activity of the NKX3.1 promoter were investigated by Western blotting or reporter gene assay, respectively. Finally, Western blotting and electrophoretic mobility shift assay were performed to demonstrate the effect of curcumin on the expression of AR and its binding activity to the androgen response element (ARE).

RESULTS

Curcumin downregulated the expression of NKX3.1 and the activity of the NKX3.1 1040 bp promoter in LNCaP cells. R1881 increased the expression of NKX3.1, and the AR antagonist flutamide decreased the expression of NKX3.1 in LNCaP cells, while curcumin could inhibit androgen-AR mediated induction of NKX3.1 expression. Curcumin decreased the expression of AR and the binding activity to ARE directly.

CONCLUSION

Curcumin could downregulate NKX3.1 expression in LNCaP cells. It could also inhibit the androgen-AR mediated induction of NKX3.1 expression by downregulating AR expression and blocking its DNA binding activity.

[Up-regulates the expression of maspin gene in prostate cancer cell line LNCaP]

AIM

To study the effect of curcumin on the apoptosis of prostate cancer cell line LNCaP and regulation of expression of maspin gene.

METHODS

MTT and DNA electrophoresis were used to examine the cell growth and apoptosis of prostate cancer cell line LNCaP after treated with different doses of curcumin. The expression of maspin gene at transcription level and translation level was also detected by RT-PCR and Western blotting. pGL3-maspin luciferase expression vector, containing 847 bp (- 764 -/+ 83) DNA of maspin gene 5' promoter region, was transient transfected into LNCaP cell. Through detecting the activity of luciferase, the effect of curcumin on the promoter of maspin was studied.

RESULTS

Curcumin inhibited cell growth, induced the apoptosis and enhanced the expression of maspin gene in LNCaP cells.

CONCLUSION

Curcumin up-regulated expression of maspin gene in LNCaP cells through enhancing the transcription activity of promoter of maspin gene.

Effects of 9-cis retinoic acid on human homeobox gene NKX3.1 expression in prostate cancer cell line LNCaP

AIM

To study the regulatory effects of 9-cis retinoic acid (RA) on the expression of human homeobox gene NKX3.1 in prostate cancer cell line LNCaP.

METHODS

Flow cytometry, reverse transcriptase polymerase chain reaction and Western blotting were performed to evaluate the effects of 9-cis RA on NKX3.1 expression and cell cycle of LNCaP cells. To identify a regulatory region within the NKX3.1 promoter contributing to the regulation induced by 9-cis RA, we have constructed an NKX3.1 promoter-reporter plasmid, pGL3-1040bp, and its 5'-deletion mutants, which were transfected into LNCaP cells with treatment of 9-cis RA in indicated concentrations.

RESULTS

With the treatment of 9-cis RA, the NKX3.1 promoter activity was increased in reporter gene assay and NKX3.1 expression was enhanced at both mRNA and protein levels in LNCaP cells. We found that the region between -936 and -921 in the upstream of NKX3.1 gene involved the inducible regulation by 9-cis RA treatment. In flow cytometry, 9-cis RA treatment caused accumulation of cells in the G(1) phase of the cell cycle and a fewer cells pass through to G(2)/M.

CONCLUSION

Our results demonstrated that 9-cis RA as a differentiating agent can arrest prostate cancer cells in G(1) phase and reduce cell mitosis, and upregulate the expression of human homeobox gene NKX3.1, which is thought to play an important role in prostate differentiation and to act as a tumor suppressor gene in the prostate.

Gum mastic inhibits the expression and function of the androgen receptor in prostate cancer cells

Accumulating evidence suggests that the androgen receptor (AR) may play an important role in the development and progression of prostate cancer. To find new, useful compounds that effectively may attenuate the function of AR in prostate cancer cells, the authors investigated the effect of gum mastic, a natural resin, on AR activity. An androgen-responsive prostate cancer cell line LNCaP was used as a model for this study. Gene transfer, reverse transcriptase-polymerase chain reaction analysis, electrophoretic mobility shift assay, and Western blot analysis were used to test the effect of gum mastic on the expression and function of the AR. To demonstrate the inhibitory effect of gum mastic on the function of the AR, the expression of androgen-regulated genes, including prostate-specific antigen (PSA), human kallikrein 2 (hK2), and NKX3.1 were measured. In addition, transient transfection assays with the PSA promoter and the AR promoter also were used to test the effects of mastic. The results showed that gum mastic inhibited the expression of the AR at the transcriptional level, resulting in the down-regulation of both AR messenger RNA and protein levels. Therefore, the function of the AR was inhibited, as reflected by the reduced expression of NKX3.1 and PSA and by androgen-stimulated growth. Because gum mastic exhibited a strong in vitro potency to attenuate the expression and function of the AR, further investigation will be required to determine whether this naturally occurring substance has in vivo potency to inhibit prostate cancer development.

Identification of a positive Cis-element upstream of human NKX3.1 gene

NKX3.1 is a prostate-specific homeobox gene related to prostate development and prostate cancer. In this work, we aimed to identify precisely the functional cis-element in the 197 bp region (from -1032 to -836 bp) of the NKX3.1 promoter (from -1032 to +8 bp), which was previously identified to present positive regulatory activity on NKX3.1 expression, by deletion mutagenesis analysis and electrophoretic mobility shift assay (EMSA). A 16 bp positive cis-element located between -920 and -905 bp upstream of the NKX3.1 gene was identified by deletion mutation analysis and proved to be a functional positive cis-element by EMSA. It will be important to further study the functions and regulatory mechanisms of this positive cis-element in NKX3.1 gene expression.

Identification of androgen-responsive element ARE and Sp1 element in the maspin promoter

Maspin is a serine protease inhibitor (serpin) with tumor-suppressing function in mammary gland. It is down-regulated in primary prostate cancer cells and lost in metastatic cells. To better understand the transcriptional regulation of maspin gene, the 860bp (-765 approximately +95) of its promoter sequence was amplified by PCR from the human genomic DNA. Then this 860bp sequence and a series of deletions from 5' and 3' ends were inserted into the upstream of luciferase reporter gene respectively. Results from dual luciferase reporter assay and electrophoretic mobility shift assay indicated that there were a negative androgen-responsive element (ARE) in the region of -277 to -262 and a positive Sp1 element in the region of +14 to +35, respectively. In addition, androgen receptor (AR) can recognize and bind to the ARE element, and then inhibit the activity of maspin promoter.

Up-regulation of NKX3.1 expression and inhibition of LNCaP cell proliferation induced by an inhibitory element decoy

NKX3.1 is an androgen-regulated prostate-specific homeobox gene that is thought to play an important role in prostate development and cancerogenesis. NKX3.1 acts as a tumor suppressor gene specifically in the prostate. Up-regulation of NKX3.1 gene offers a promising gene therapy for prostate cancer. The decoy strategy has been developed and is considered a useful tool for regulating gene expression and gene therapy. In our previous studies, we identified a 20 bp inhibitory element upstream of the NKX3.1 promoter. In this study, we focused on using the 20 bp inhibitory element decoy to block negative regulation of the NKX3.1 gene and to up-regulate NKX3.1 expression using synthetic double-stranded oligodeoxynucleotides of the 20 bp inhibitory element. We found in an electrophoretic mobility shift assay experiment that the 20 bp inhibitory decoy presented competitive binding to a specific binding protein of the 20 bp inhibitory element in prostate cancer cell line LNCaP. In luciferase reporter gene assays, we found that the 20 bp inhibitory decoy could enhance NKX3.1 promoter activity, and RT-PCR and Western blot analysis revealed that NKX3.1 expression was up-regulated effectively by the transfection with the 20 bp inhibitory decoy. Furthermore, cell proliferation was inhibited by up-regulated NKX3.1 expression induced by the 20 bp inhibitory decoy.

Molecular cloning and characterization of human homeobox gene Nkx3.1 promoter

Nkx3.1 is a prostate-specific homeobox gene related strongly to prostate development and prostate cancer. To study its regulation of transcription, 1.06 kb 5' flanking region of Nkx3.1 gene and its 5' deletion mutants (861, 617, 417 and 238 bp) were obtained by PCR and cloned into pGL(3)-basic, a promoter-less luciferase reporter vector, to examine their promoter activities driving the reporter gene transcription. pRL-TK, a Renilla luciferase reporter vector was used as internal control, and pGL(3)-control and pGL(3)-basic were used as positive and negative control respectively. The promoter activities were determined by dualluciferase reporter assay 48 h after pGL(3) constructs were cotransfected with pRL-TK into prostate cancer cell LNCaP. The results showed that dual-luciferase reporter assay (M(1)/M(2)) of pGL(3)-1.06 kb cotransfection with pRL-TK was 2.7, which was about 1.5-fold higher than that of pGL(3)-control cotransfection with pRL-TK and 50-fold higher than that of pGL(3)-basic cotransfection with pRL-TK. The results also showed that the relative activities (M(1)/M(2)) were 0.71, 0.84, 0.44 and 2.07 respectively for pGL(3)-861 bp, pGL(3)-617 bp, pGL(3)-417 bp, pGL(3)-238 bp, the last one still had 80% promoter activity compared with pGL(3)-1.06 kb, which showed that deletion from 1.06 kb to 238 bp had small effects on promoter activity. The conclusion was that the 238 bp fragment containing a TATA box and two CAAT boxes had strong promoter activity. However, the deletion from 1.06 kb to 861 bp reduced activity 3.8-fold while the deletion from 417 bp to 238 bp enhanced activity 4.7-fold, which indicated that these deleted sequences might contain some important positive or negative regulatory elements. It will be important to identify the elements within the Nkx3.1 promoter that contribute to regulation of the gene transcription in the future studies.

Chemical Modification of N-acetylglucosaminyltransferases

The essential groups of three N-acetylglucosaminyltransferases (GnTs) of rat kidney were studied by using chemical modification and substrate protection methods. It was found that the amino and indolyl groups were the common essential groups of GnT-III, GnT-IV and GnT-V. Amino group was proposed to participate in the binding of common donor substrate--UDP-GlcNAc. Indolyl group might be the binding group of acceptor substrate--Gn(2)M(3)Gn(2)-PA heptosaccharide glycan for GnT-III and GnT-IV, and it might be the essential group but not substrate-binding for GnT-V. Guanidino group was also supposed to be one of the donor substrate-binding groups of GnT-III, but was a non-substrate-binding essential group for GnT-IV and a non-essential group for GnT-V, respectively. Carboxyl group might be the binding group of acceptor substrate for GnT-V, but the non-substrate-binding essential group for GnT-III and non-essential for GnT-V, respectively. In contrast, sulfhydryl, hydroxyl and imidazolyl groups were found to be non-essential groups of the three GnTs. The effects of amino sugars on GnT-III and GnT-V also showed the difference in essential groups in the active centers of GnT-III and GnT-V.

Opposing changes in N-acetylglucosaminyltransferase-V and -III during the cell cycle and all-trans retinoic acid treatment of hepatocarcinoma cell line

The changes in N-acetylglucosaminyltransferase-V and -III (GnT-V, GnT-III) during the cell-cycle of synchronized 7721 human hepatocarcinoma cell line were investigated. Using an HPLC method to assay GnT and flow cytometry (FCM) for cell cycle analysis, it was found that GnT-V showed the highest activity, but GnT-III reached the lowest activity when G(2)/M cells were most abundant. In contrast, GnT-V declined to the minimum while GnT-III elevated to maximum when G(0)/G(1) cells were most predominant. The opposing changes were more obvious when the activities of GnT-V and GnT-III were expressed as relative activities (activity of GnT-V or GnT-III/the sum of activities of GnT-V plus GnT-IV plus GnT-III). These opposing changes of GnT-V and GnT-III during the cell cycle might result from the different regulatory mechanisms of GnT-V and GnT-III expression in the cell cycle. The alterations in the structures of cell surface N-glycans were compatible with the changes of the activities of GnTs. The results from immunocytochemistry and Northern blot showed that the protein and mRNA contents of GnT-V were not significantly changed during the cell cycle. The activity of a cell cycle regulating protein kinase, p34(cdc2) kinase, correlated to the activity of GnT-V. These findings suggested that the change of GnT-V activity in cell cycle was not the consequence of the alteration of gene transcription or enzyme protein synthesis, but might be caused by the post-translational regulation. The decrease in GnT-V and the corresponding increase in GnT-III activities were also found after the cells were treated with all-trans retinoic acid (ATRA), and the mechanism of this might be different from that in the cell cycle.

[Changes with cell cycle of N-acetylglucosaminyl transferase III, IV and V in 7721 human hepatocarcinoma cells]

In order to investigate the changes of N-acetylglucosaminyl transferase (GlcNAc-T) III, IV and V in cell cycle, the synchronization of 7721 human hepatocellular carcinoma cells was performed using serum hunger method. The percentages of cells in different phases during cell cycle were measured by flow cytometry (FCM) and the cell cycle was checked by determining the activity of cellular p34cdc2 kinase. It was found that the activities of GlcNAc-T III increased in G0/G1 cell peak phase and had correlation with the cell percentage of G0/G1 phase (r = 0.760, P < 0.05), while GlcNAc-T V showed the highest activity when G2/M cells were most abundant and had an apparent correlation with the cell percentage of G2/M phase (r = 0.868, P < 0.001). The changes of GlcNAc-T IV activity seemed not related to the cell cycle. The changes in opposite directions of relative activities (percentage of total GlcNAc-T III, IV, V) of GlcNAc-T III and GlcNAc-T V were observed during cell cycle (r = -0.951, P < 0.001), suggesting that these two enzymes might be regulated differently and functioned oppositely in the cells: GlcNAc-T V may be related to the proliferation of 7721 cells, while GlcNAc-T III may be related to the non-mitotic silence phase of the cells, or, it may be a factor against proliferation. Immunohistochemical results showed that the protein content of GlcNAc-T V was not significantly changed during cell cycle, and had no correlation with the activity of GlcNAc-T V, suggesting that the changes of GlcNAc-T V activity in cell cycle might not be resulted from the alteration of enzyme protein synthesis. The correlation between the activities of GlcNAc-T V and p34cdc2 kinase (r = 0.752, P < 0.05) was observed in cell cycle, implicating that GlcNAc-T V might possibly be regulated by p34cdc2 kinase.