Search

Immunodeficient murine models are usually used as the preclinical models of osteosarcoma. Such models do not effectively simulate the process of tumorigenesis and metastasis. Establishing a suitable animal model for understanding the mechanism of osteosarcoma and the clinical translation is indispensable. The UMR-106 cell suspension was injected into the marrow cavity of Balb/C nude mice. Tumor masses were harvested from nude mice and sectioned. The tumor fragments were transplanted into the marrow cavities of SD rats immunosuppressed with cyclosporine A. Through muti-rounds selection in SD rats, we constructed orthotopic osteosarcoma animal models using rats with intact immune systems. The primary tumor cells were cultured in-vitro to obtain the immune-tolerant cell line. VX2 tumor fragments were transplanted into the distal femur and parosteal radius of New Zealand white rabbit to construct orthotopic osteosarcoma animal models in rabbits. The rate of tumor formation in SD rats (P1 generation) was 30%. After four rounds of selection and six rounds of acclimatization in SD rats with intact immune systems, we obtained immune-tolerant cell lines and established the orthotopic osteosarcoma model of the distal femur in SD rats. Micro-CT images confirmed tumor-driven osteolysis and the bone destruction process. Moreover, the orthotopic model was also established in New Zealand white rabbits by implanting VX2 tumor fragments into rabbit radii and femurs. We constructed orthotopic osteosarcoma animal models in rats with intact immune systems through muti-rounds in-vivo selection and the rabbit osteosarcoma model. [ABSTRACT FROM AUTHOR]

Background and purpose: This study aims to explore the advantages and robustness of the partial arc combined with prone position planning technique for radiotherapy in rectal cancer patients. Adaptive radiotherapy is recalculated and accumulated on the synthesis CT (sCT) obtained by deformable image registration between planning CT and cone beam CT (CBCT). Full and partial volume modulation arc therapy (VMAT) with the prone position on gastrointestinal and urogenital toxicity, based on the probability of normal tissue complications (NTCP) model in rectal cancer patients were evaluated. Materials and methods: Thirty-one patients were studied retrospectively. The contours of different structures were outlined in 155 CBCT images. First, full VMAT (F-VMAT) and partial VMAT (P-VMAT) planning techniques were designed and calculated using the same optimization constraints for each individual patient. The Acuros XB (AXB) algorithm was used in order to generate more realistic dose distributions and DVH, considering the air cavities. Second, the Velocity 4.0 software was used to fuse the planning CT and CBCT to obtain the sCT. Then, the AXB algorithm was used in the Eclipse 15.6 software to conduct re-calculation based on the sCT to obtain the corresponding dose. Furthermore, the NTCP model was used to analyze its radiobiological side effects on the bladder and the bowel bag. Results: With a CTV coverage of 98%, when compared with F-VMAT, P-VMAT with the prone position technique can effectively reduce the mean dose of the bladder and the bowel bag. The NTCP model showed that the P-VMAT combined with the prone planning technique resulted in a significantly lower complication probability of the bladder (1.88 ± 2.08 vs 1.62 ± 1.41, P = 0.041) and the bowel bag (1.28 ± 1.70 vs 0.95 ± 1.52, P < 0.001) than the F-VMAT. In terms of robustness, P-VMAT was more robust than F-VMAT, considering that less dose and NTCP variation was observed in the CTV, bladder and bowel bag. Conclusion: This study analyzed the advantages and robustness of the P-VMAT in the prone position from three aspects, based on the sCT fused by CBCT. Whether it is in regards to dosimetry, radiobiological effects or robustness, P-VMAT in the prone position has shown comparative advantages. [ABSTRACT FROM AUTHOR]

Background: European researchers have underscored associations between single nucleotide polymorphism (SNP) rs2287622 of the hepatobiliary bile salt export pump (BSEP) gene and the risk of hepatitis C virus (HCV) infection. The distributions of SNP rs2287622 are racially specific. This study was aimed to preliminarily investigate the distribution of BSEP gene SNP rs2287622 in the Han patients with chronic HCV-infection (CHC) in Hunan, China.Methods: BSEP gene SNP rs2287622 of 165 CHC patients, 99 patients with chronic hepatitis B virus infection (CHB) and 99 healthy individuals were analyzed by polymerase chain reaction-restriction fragment length polymorphism analysis and nucleotide sequencing.Results: The overall frequencies of the C allele of BESP gene SNP rs2287622 in the CHC patients, CHB patients and healthy individuals were 74.2, 72.7 and 74.2%, respectively (P > 0.05). The overall odds ratios (ORs) aiming at predicting CHC risk by comparing the ratios of the frequency distribution of alleles or genotypes in the CHC group with those in the non-CHC group had no statistical significance (P > 0.05). However, the CHC ORs of CC vs TT, TC vs TT and CC + CT vs TT among the individuals aged over 40 years were 2.680, 3.122 and 2.824 respectively (P < 0.05), and the higher risk did not relate to gender, HCV genotypes and presence of HCV-related liver cirrhosis.Conclusions: Among the Han individuals aged over 40 years in Hunan, China, genotype CC or CT of BSEP gene SNP rs2287622 may correlate with higher risk of CHC in comparison with genotype TT. Further study with a larger cohort is essential. [ABSTRACT FROM AUTHOR]

Background: Pancreatic cancer is one of the most lethal human cancers. N6-methyladenosine (m6A), a common eukaryotic mRNA modification, plays critical roles in both physiological and pathological processes. However, its role in pancreatic cancer remains elusive. Methods: LC/MS was used to profile m6A levels in pancreatic cancer and normal tissues. Bioinformatics analysis, real-time PCR, immunohistochemistry, and western blotting were used to identify the role of m6A regulators in pancreatic cancer. The biological effects of methyltransferase-like 14 (METTL14), an mRNA methylase, were investigated using in vitro and in vivo models. MeRIP-Seq and RNA-Seq were used to assess the downstream targets of METTL14. Results: We found that the m6A levels were elevated in approximately 70% of the pancreatic cancer samples. Furthermore, we demonstrated that METTL14 is the major enzyme that modulates m6A methylation (frequency and site of methylation). METTL14 overexpression markedly promoted pancreatic cancer cell proliferation and migration both in vitro and in vivo, via direct targeting of the downstream PERP mRNA (p53 effector related to PMP-22) in an m6A-dependent manner. Methylation of the target adenosine lead to increased PERP mRNA turnover, thus decreasing PERP (mRNA and protein) levels in pancreatic cancer cells. Conclusions: Our data suggest that the upregulation of METTL14 leads to the decrease of PERP levels via m6A modification, promoting the growth and metastasis of pancreatic cancer; therefore METTL14 is a potential therapeutic target for its treatment. [ABSTRACT FROM AUTHOR]

Background: Corynebacterium glutamicum (C. glutamicum) has traditionally been used as a microbial cell factory for the industrial production of many amino acids and other industrially important commodities. C. glutamicum has recently been established as a host for recombinant protein expression; however, some intrinsic disadvantages could be improved by genetic modification. Gene editing techniques, such as deletion, insertion, or replacement, are important tools for modifying chromosomes., Results: In this research, we report a CRISPR/Cas9 system in C. glutamicum for rapid and efficient genome editing, including gene deletion and insertion. The system consists of two plasmids: one containing a target-specific guide RNA and a homologous sequence to a target gene, the other expressing Cas9 protein. With high efficiency (up to 100%), this system was used to disrupt the porB, mepA, clpX and Ncgl0911 genes, which affect the ability to express proteins. The porB- and mepA-deletion strains had enhanced expression of green fluorescent protein, compared with the wild-type stain. This system can also be used to engineer point mutations and gene insertions., Conclusions: In this study, we adapted the CRISPR/Cas9 system from S. pyogens to gene deletion, point mutations and insertion in C. glutamicum. Compared with published genome modification methods, methods based on the CRISPR/Cas9 system can rapidly and efficiently achieve genome editing. Our research provides a powerful tool for facilitating the study of gene function, metabolic pathways, and enhanced productivity in C. glutamicum.

Background: European researchers have underscored associations between single nucleotide polymorphism (SNP) rs2287622 of the hepatobiliary bile salt export pump (BSEP) gene and the risk of hepatitis C virus (HCV) infection. The distributions of SNP rs2287622 are racially specific. This study was aimed to preliminarily investigate the distribution of BSEP gene SNP rs2287622 in the Han patients with chronic HCV-infection (CHC) in Hunan, China., Methods: BSEP gene SNP rs2287622 of 165 CHC patients, 99 patients with chronic hepatitis B virus infection (CHB) and 99 healthy individuals were analyzed by polymerase chain reaction-restriction fragment length polymorphism analysis and nucleotide sequencing., Results: The overall frequencies of the C allele of BESP gene SNP rs2287622 in the CHC patients, CHB patients and healthy individuals were 74.2, 72.7 and 74.2%, respectively (P > 0.05). The overall odds ratios (ORs) aiming at predicting CHC risk by comparing the ratios of the frequency distribution of alleles or genotypes in the CHC group with those in the non-CHC group had no statistical significance (P > 0.05). However, the CHC ORs of CC vs TT, TC vs TT and CC + CT vs TT among the individuals aged over 40 years were 2.680, 3.122 and 2.824 respectively (P < 0.05), and the higher risk did not relate to gender, HCV genotypes and presence of HCV-related liver cirrhosis., Conclusions: Among the Han individuals aged over 40 years in Hunan, China, genotype CC or CT of BSEP gene SNP rs2287622 may correlate with higher risk of CHC in comparison with genotype TT. Further study with a larger cohort is essential.

Background: Significant challenges, including low expression and extracellular secretion of soluble protein, are encountered in expressing and purifying Bacillus acidopullulyticus pullulanase (BaPul) in Escherichia coli., Methods: An N-terminal domain truncation was adopted to facilitate BaPul variant expression and/or secretion., Results: BaPul possesses a complex modular architecture that consists of CBM41-X45a-X25-X45b-CBM48-GH13. The activities of M1 (ΔCBM41) and M5 (ΔCBM41ΔX25) variants were 2.9- and 2.4-fold that of wild-type (WT) enzyme, respectively. The enhanced expression of soluble protein is the main reason for these improved activities. PelB-M1 and PelB-M5 were transported to the periplasmic space, where PelB is part of the PelB-pET28a(+) construct, and PelB-M3 (ΔX25) and PelB-WT variants were largely retained in the cytoplasm. After fermentation, about 56.6 and 93.4 % of the total activity of PelB-M1 and PelB-M5 were transferred to the periplasm, respectively, followed by cell lysis and leakage of the partial enzyme into the extracellular medium. The optimal temperature and pH for purified preparations of M1, M3, and M5 were similar to those of the WT enzyme. In a starch saccharification reaction, the dextrose equivalents of M1, M3, and M5 proteins were 94.7, 94.5, and 93.1 %, respectively, which were also essentially identical to that of WT (93.6 %)., Conclusion: The deletion of CBM41 and/or X25 domain did not affect the enzyme application, and the truncated variants were more highly expressed and secreted in E. coli. Thus, the truncated variants may be more suitable for industrial applications.

Background: Corncob as one of the most suitable feedstock for the production of a variety of high-value-added chemicals is receiving increasing attention worldwide because of the characteristics of high carbohydrate (cellulose and hemicelluloses) contents and high energy densities. Furfural produced from hemicelluloses is a highly versatile and key feedstock used in the manufacture of a wide range of biofuel and important chemicals in different fields. Achieving high furfural yields from corncob combining green approaches and efficient equipment has the promising potential for biomass-to-biofuel technologies. To understand the dissolving mechanism of corncob sugars and reveal the relationship between the hydrolysate composition and furfural yields, a two-step approach was proposed using microwave-assisted hydrothermal pretreatment and subsequently heterogeneous catalytic process., Results: Released hemicelluloses in the first stage were mainly in forms of monosaccharide, oligosaccharides, and water-soluble polysaccharide. Hydrolysates with the maximum xylose content (99.94 mg g(-1), 160 °C, 90 min), the maximum xylobiose content (20.89 mg g(-1), 180 °C, 15 min), and the maximum total xylose content in monosaccharide and oligosaccharides (DP ≤ 6) (272.06 mg g(-1), 160 °C, 60 min) were further converted to furfural using tin-loaded montmorillonite as the catalyst in a biphasic system. The highest furfural yield (57.80 %) was obtained at 190 °C for 10 min from hydrolysates with the maximum xylose content. Moreover, controlled experiments showed that furfural yields from corncob hydrolysates were higher than those from the pure xylose solutions, and lower initial xylose concentration may be in favor of the furfural production., Conclusions: This work provides an efficient approach to produce furfural by a two-step process for the biomass-to-biofuel industry. Results indicated that the production of furfural from biomass raw materials can be controlled by the depolymerization degree of hemicelluloses.

Background: The microscopic residual tumor at the bronchial margin after radical surgery (R1 resection) affects prognosis negatively in non-small-cell lung cancer (NSCLC) patients. For patients with good performance status, a potential cure still exists. Here, we report the outcomes of concurrent paclitaxel-based chemo-radiotherapy (CRT) for NSCLC patients with microscopically positive bronchial margins or peribronchial infiltration., Methods: A retrospective search in the clinical database was conducted in three hospitals. Patients were identified and evaluated if treated with radiotherapy combined with paclitaxel-based chemotherapy. The objects analyzed were local control time, progression-free survival (PFS), overall survival (OS), and treatment-related toxicity., Results: Sixty-one patients with microscopic residual tumor at the bronchial stump following pulmonary lobectomy were identified. Forty-six patients who had received concurrent paclitaxel-based CRT were analyzed. The median follow-up was 40 months (range: 15.0-77.5 months). The 1-, 2- and 3-year survival rates were 97.8%, 60.9% and 36.9%, respectively. The local recurrences were recorded in 19.6% (9/46) patients. Median PFS and OS for the evaluated cohort were 23.0 [95% confidence interval (CI): 21.3-24.7] and 32.0 (95% CI: 23.7-40.3) months, respectively. The most common side effects were hematological toxicity (neutropenia, 93.5%; anemia, 89.1%; and thrombocytopenia, 89.1%) and no treatment-related deaths. Grade ≥2 acute radiation-induced pneumonitis and esophagitis were recorded in 43.5% (20/46) and 26.1% (12/46) patients, respectively. By univariate analysis, non-squamous cell lung cancer was associated with a significantly longer survival time (45.1 vs 26.4 months, p = 0.013)., Conclusions: For NSCLC patients with post-surgical microscopic residual tumor at the bronchial stump, concurrent paclitaxel-based chemo-radiotherapy achieved promising outcomes with accepted treatment-related toxicity.