[Effects of different organic amendments on soil organic carbon and its labile fractions in the paddy soil of a double rice cropping system]. / æœ‰æœºç‰©æ–™è¿˜ç”°å¯¹åŒå­£ç¨»ç”°åœŸå£¤æœ‰æœºç¢³åŠå ¶æ´»æ€§ç»„åˆ†çš„å½±å“.

Application of organic amendments is an effective approach for improving soil organic carbon and soil fertility. To investigate the effects of different organic amendments on soil organic carbon and its labile fraction content, a batch of incubation experiments was conducted on the fluvo-aquic soil in Dongting Lake region, Hunan Province. There were six treatments, including soil amended with rice straw, soil amended with Chinese milk vetch, soil amended with bio-organic fertilizer, soil amended with pig manure, and soil amended with rice straw-derived biochar, with unamended soil as control. Each treatment had the same amount of carbon input. After 180 days of incubation, application of organic amendments increased soil labile organic carbon content. Application of bio-organic fertilizer, pig manure and rice straw-derived biochar significantly increased soil organic carbon content by 26.1%, 9.7% and 30.7%, respectively. There was no significant change in soil organic carbon content in rice straw and Chinese milk vetch treatments which were more favourable to the accumulation of soil dissolved organic carbon and microbial biomass carbon. Pig manure was more favourable to the accumulation of soil dissolved organic carbon. Bio-organic fertili-zer could benefit the accumulation of soil microbial biomass carbon and readily oxidizable organic carbon. Rice straw-derived biochar could promote the accumulation of soil microbial biomass carbon and light fraction organic carbon. Compared with rice straw, soil carbon pool management index was increased by 31.8%, 111.6%, 62.2% and 50.7% in Chinese milk vetch, bio-organic fertilizer, pig manure and rice straw-derived biochar treatments, respectively. The performance of bio-organic fertilizer, pig manure, and rice straw biochar was better than rice straw and Chinese milk vetch from the perspective of soil carbon sequestration and soil carbon pool management index.

Rotundic acid induces Cas3-MCF-7 cell apoptosis through the p53 pathway.

In the present study, the functions and mechanisms of rotundic acid (RA) underlying its induction of apoptosis in caspase-3-transfected MCF-7 human breast cancer cells (Cas3-MCF-7 cells) were investigated. RA induced apoptosis in Cas3-MCF-7 cells more efficiently compared with that in MCF-7 cells transfected with control plasmid. The results from an MTT assay demonstrated that RA effectively inhibited Cas3-MCF-7 cell viability in a dose-dependent manner and induced cell apoptosis via caspase-3 activity within 12 to 48 h. Western blotting and fluorescence-activated cell sorting demonstrated that RA initiated Cas3-MCF-7 cell apoptosis via p53 activation. The silencing of the p53 gene in the Cas3-MCF-7 cell line led to decreased RA-induced Cas3-MCF-7 cell caspase-3 activity and cell apoptosis. Collectively, the results of the present study indicate that caspase-3 serves a critical function in rotundic acid-induced apoptosis, and suggest that caspase-3 deficiency may contribute to the chemotherapy-resistance of breast cancer. Reconstitution of caspase-3 sensitizes MCF-7 breast cancer cells to chemotherapy. RA has the potential for development as a novel drug combined with reconstitution of caspase-3 gene therapy for the treatment of human breast cancer with caspase-3 deficiency.

Rotundic acid enhances the impact of radiological toxicity on MCF-7 cells through the ATM/p53 pathway.

Although radiation therapy is a powerful anticancer modality, radiation- induced stress response and gene expression with adaptive resistance may severely compromise the effectiveness of radiation. The function of rotundic acid (RA) on inducing apoptosis in the human breast cancer cell line MCF-7 has been investigated in a previous study. In the present study, the combined effect of chemotherapy and radiotherapy on reducing side effects was examined. The results of an MTT assay revealed that radiation (0.5, 2 and 10 Gy) effectively inhibit MCF-7 cell viability in a dose-dependent manner, consistent with the effects of RA (2, 5 and 12.5 µM). Interestingly, a lower dose of radiation (1 Gy) combined with RA (5 µM) exhibited a greater inhibition efficiency compared with a high dose of radiation alone. Flow cytometry revealed that radiation combined with RA induced the apoptosis of MCF-7 cells. Using western blotting, it was demonstrated that radiation induced the expression of ataxia-telangiectasia mutated (ATM) and p53 protein, and that RA enhanced this effect. On examining the potential underlying mechanism, it was revealed that radiation and RA combined induce Bcl-2-associated X protein expression and cell apoptosis in MCF-7 cells. An ATM inhibitor was able to restore the effect of radiation and RA on inducing MCF-7 cell apoptosis. These results suggest that the ATM/p53 pathway directly participates in radiation and RA-induced apoptosis in MCF-7 cells. RA has the potential for development as a novel drug for the treatment of human breast cancer combined with radiation therapy, given that the combined side effects are reduced.

Therapeutic effect of chitosan on CCl4­induced hepatic fibrosis in rats.

Chitosan is a linear polysaccharide that is made by treating the chitin shells of shrimp and crustaceans with an alkaline substance, for example sodium hydroxide. Due to its unique physical and chemical properties, chitosan has a wide range of applications in the medical field. Currently, there are no effective treatments for liver fibrosis; therefore, the aim of the present study was to investigate the therapeutic effect of chitosan in a CCl4­induced hepatic fibrosis (HF) rat model. The serum levels of aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP) were measured by ELISA. Collagen (COL) 3 and α­smooth muscle actin (SMA) expression levels in the rat liver were detected by reverse transcription­semiquantitative polymerase chain reaction and western blotting, respectively. The results demonstrated that treatment with chitosan significantly improved HF, by decreasing the serum levels of AST, ALT, and ALP; improving liver histology; and decreasing the expression levels of COL3 and α­SMA. Chitosan may offer an alternative approach for the clinical treatment of HF.

Low-dose irradiation inhibits proliferation of the p53null type human prostate cancer cells through the ATM/p21 pathway.

Low-dose ionizing radiation (LDIR) induces hormesis, exerts an adoptive effect on normal mammalian cells and stimulates cell proliferation; however, this effect is absent in cancer cells. Little is known on the molecular mechanisms underlying this differential response between normal and cancer cells. In the present study, it was demonstrated that the human prostate cancer cell line PC-3 and the normal prostate cell line RWPE-1 exhibited differential biological responses to LDIR. Through cell cycle analyses, it was demonstrated that LDIR inhibited cell growth and arrested the cell cycle at the S and G2/M phases in PC-3 cells, but not in RWPE-1 cells. Using western blotting, it was demonstrated that LDIR at 75 mGy induced the expression of ataxia-telangiectasia mutated (ATM) protein in PC-3 as well as RWPE-1 cells. However, the ATM̸p21 pathway was activated in PC-3, but not in RWPE-1 cells. Although the expression of p53 was not affected by 75 mGy LDIR in RWPE-1 cells, the ATM̸p21 pathway was activated when RWPE-1 cells lost p53 function. In addition, when using ATM inhibitors, the ATM̸p21 pathway was inactivated in both cell lines, and the LDIR-induced cell proliferation inhibition was also abolished. These findings suggested that the ATM/p21 pathway directly participated in the LDIR-induced cell proliferation inhibition in p53null type prostate tumor cells, whereas this mechanism was absent in normal prostate cells. Thus, p53 may affect cell stability following LDIR, and plays a crucial role in regulating the ATM/p21 pathway activated by LDIR.

Sodium cantharidinate induces HepG2 cell apoptosis through LC3 autophagy pathway.

The function of sodium cantharidinate on inducing hepatocellular carcinoma cell apoptosis was investigated for the first time. Sodium cantharidinate inhibits HepG2 cell growth mainly by LC3 autophagy pathway. MTT results show that sodium cantharidinate effectively inhibits the proliferation of HepG2 cells in a dose- and time-dependent manner and induce cell apoptosis by caspase-3 activity. The further western blotting and FACS detection show that sodium cantharidinate initiates HepG2 cell autophagy program by LC3 pathway. Autophagy-specific inhibitor 3-MA reduce sodium cantharidinate-induced caspase-3 activity and HepG2 cell apoptosis. Silence of the LC3 gene in HepG2 cell lines also reduce sodium cantharidinate-induced cell apoptosis. Collectively, our data indicate that sodium cantharidinate induces HepG2 cell apoptosis through LC3 autophagy pathway. Sodium cantharidinate has potential for development as a new drug for treatment of human HCC.

A novel engineered interferon-α hybrid molecule increases anticancer efficacy of doxorubicin in breast cancer chemotherapy.

Breast cancer is the most common carcinoma among Chinese women. Interferon α (IFNα) has been used to treat various types of cancer, including breast cancer, but its antitumor activity is relative low, which significantly hinders its clinical application. In this study, we utilized a Ph.D.-12 peptide library screening system to identify a short peptide that specifically binds to MCF-7 breast cancer cells. By fusing the MCF-7 binding peptide (MBP) to the C-terminus of IFNα, we constructed an engineered IFNα-MBP fusion molecule (IMBP), and applied this novel fusion protein to the treatment of breast cancer. We found that IMBP exhibited significantly higher activity than wild-type IFNα in inhibiting cell growth and inducing cell apoptosis. Additionally, IMBP potentiated the therapeutic efficacy of doxorubicin-based breast cancer chemotherapy via the activation of cell cycle arrest and cell apoptosis pathway genes including p53, p21, CDK2, cyclin A, caspase 9, Bcl-2 and Bax. The enhanced activity of the synthetic IMBP was also associated with the activation of signal transducer and activation of transcription 1 (STAT1) pathway target genes (STAT1, IFIT1, IFITM1 and MX1). This study evaluated the potential value of the synthetic IMBP as a novel anti-breast cancer agent.

Low-dose irradiation promotes proliferation of the human breast cancer MDA-MB-231 cells through accumulation of mutant P53.

Low-dose irradiation (LDIR) has been proven to have differential biological effects on normal mammalian somatic cells and cancer cells. Our previous study showed that p53 gene status is a critical factor regulating the effect of LDIR on cancer cells. We investigated the effect of LDIR on the breast cancer cell line MDA-MB-231 that harbors a mutant p53 gene, and the normal breast fibroblast cell line Hs 578Bst. In the present study, we showed that 150 mGy LDIR pormoted growth of MDA-MB-231 cells but not Hs 578Bst cells. Through cell cycle analyses, we found that LDIR accelerated cell cycle into S phase in MDA-MB-231 cells, but did not affect the cell cycle of Hs 578Bst cells. Using western blotting, we demonstrated that the expression of CDK4, CDK6 and cyclin D1 was upregulated in MDA-MB-231 cells after LDIR. Although LDIR increased ataxia-telangiectasia mutated (ATM) level in both MDA-MB-231 cells and Hs 578Bst cells and activated ATM/p53/p21 pathway, only the mutant type of p53 (mtp53) protein in MDA-MB-231 cells was shown to be accumulated after LDIR. Using ATM inhibitor or lentivirus-mediated small interfering RNA (siRNA) to block the ATM/p53/p21 pathway in MDA-MB-231 cells, the LDIR-induced cell proliferation was abolished. When we introduced wild-type p53 (wtp53) protein into MDA-MB-231 cells, the LDIR-induced cell proliferation was also abolished. These findings suggest that normal p53 function is crucial in ATM/p53/p21 pathway activated by LDIR. The p53 status is the most probable reason leading to differential LDIR biological activities between breast tumor cells and normal breast cells.

Serum anti-p53 antibody detection in carcinomas and the predictive values of serum p53 antibodies, carcino-embryonic antigen and carbohydrate antigen 12-5 in the neoadjuvant chemotherapy treatment for III stage non-small cell lung cancer patients.

BACKGROUND: The serum p53 antibody (s-p53 Ab) is a valuable prognostic factor for carcinomas, but its common detection method, based on enzyme linked immunosorbent assay (ELISA), needs to be improved due to low sensitivity. Although neoadjuvant chemotherapy (NACT) is widely used in the treatment of non-small cell lung cancer (NSCLC) in China, forecasting chemoresistance is still a pressing problem. METHODS: Hybrid phage and wild-type p53 protein (wt p53 protein) were produced before the establishment of phage-ELISA and p53-ELISA. S-p53 Abs of 829 patients with various types of cancer was detected by a double ELISA system. 47 ΙΙΙ stage NSCLC patients treated with mitomycin, vindesine and cisplatin (MCV)-based NACT were chosen for s-p53 Abs, carcino-embryonic antigen (CEA) and carbohydrate antigen (CA) 12-5 predictive value analysis. RESULTS: Through the combination of p53-ELISA and phage-ELISA (p53-phage ELISA), the sensitivity of s-p53 Abs in lung, breast, colorectal, gastric, esophageal, liver and ovarian cancer increased to 39.0%, 33.3%, 41.7%, 32.1%, 30.9%, 23.1% and 43.2% respectively. S-p53 Abs proved to correlate with nodal involvement, TNM stage, histological type (in lung cancer) or tumor size (in gastric cancer). As for the 47 ΙΙΙ stage NSCLC treated with NACT, s-p53 Abs and CA12-5 remarkably decreased after NACT treatment (P=0.034 and P=0.007) and pre-NACT low s-p53 Abs correlated with high objective chemoresponse rate (P=0.016). CONCLUSIONS: p53-phage ELISA system has an edge over single p53-ELISA. S-p53 Abs level correlates with cancer patients' clinicalpathological parameters and can predict the chemoresponse of ΙΙΙ stage NSCLC patients during MCV-based NACT treatment.

Neamine inhibits cell proliferation, migration, and invasion in H7402 human hepatoma cells.

OBJECTIVE: To explore the effect of neamine on cell proliferation, migration, and invasion in H7402 human hepatoma cells. METHODS: This study was conducted at the Institute of Genetics and Cytology, School of Life Science, Northeast Normal University, Changchun, China between October 2008 and February 2010. First, we employed the MTT (thiazol blue tetrazolium bromide) and soft agar assay to detect the effect of neamine on cell proliferation, and investigated the migration and invasion by using a transwell assay in H7402 cells. We, then, investigated nuclear translocation of angiogenin by immunofluorescence staining. Finally, we stable transfected H7402 cells with the plasmids pCI-Ang (+) and pCI-Ang (-), which contain the entire coding region of human angiogenin in the sense and antisense orientations, to obtain angiogenin under-expressing/over-expressing transfectants, and investigated the effect of neamine on angiogenin induced cell proliferation. RESULTS: The results showed that neamine positively inhibited the proliferation, migration, and invasion of H7402 cells. Nuclear translocation of angiogenin was blocked by neamine, and angiogenin-induced cell proliferation was inhibited by neamine. CONCLUSION: Neamine positively inhibited H7402 cells. Since the toxicity of neamine is much less than neomycin, and is close to that of streptomycin and kanamycin, it may serve as a lead agent for the development of hepatocellular carcinoma therapeutics.