Role of STAT3 in cancer cell epithelial­mesenchymal transition (Review).

Since its discovery, the role of the transcription factor, signal transducer and activator of transcription 3 (STAT3), in both normal physiology and the pathology of numerous diseases, including cancer, has been extensively studied. STAT3 is aberrantly activated in different types of cancer, fulfilling a critical role in cancer progression. The biological process, epithelial­mesenchymal transition (EMT), is indispensable for embryonic morphogenesis. During the development of cancer, EMT is hijacked to confer motility, tumor cell stemness, drug resistance and adaptation to changes in the microenvironment. The aim of the present review was to outline recent advances in knowledge of the role of STAT3 in EMT, which may contribute to the understanding of the function of STAT3 in EMT in various types of cancer. Delineating the underlying mechanisms associated with the STAT3­EMT signaling axis may generate novel diagnostic and therapeutic options for cancer treatment.

Forensic characterisation and polymorphism analysis of 16 X-chromosomal STRs in the Jining Han population in Eastern China.

BACKGROUND: X-chromosomal short tandem repeats (X-STRs) are a useful supplementary approach to analysing autosomal markers in forensics and kinship studies; such markers are not well-characterised in many populations. AIM: To investigate population genetic polymorphism and forensic characterisation of 16 X-STRs in the Jining Han population, and analyse genetic relationships with other Chinese populations. SUBJECTS AND METHODS: Allele frequencies for 16 X-STR loci were obtained from a sample set of 527 unrelated individuals from the Jining Han population. Population genetic analyses of Jining Han and another 10 reference populations were conducted using phylogenetic tree, principal component analysis and multidimensional scaling. RESULTS: We detected 149 alleles, with frequencies ranging from 0.0013 to 0.8242. The combined powers of discrimination in males and females were 0.999999997194774 and 0.999999999999995, respectively. The combined mean exclusion change (MEC)Krüger, MECKishida, MECDesmarais, and MECDesmarais Duos values were 0.999974632649096, 0.999999976997582, 0.999999977013201, and 0.999993755768423, respectively. We detected relatively high genetic homogeneity in populations with similar ethnic or geographic origins, and a close relationship between the Jining Han and Beijing Han populations. CONCLUSIONS: The present findings indicate that the 16 X-STR loci examined are highly polymorphic in the Han population of Jining, providing useful information for forensic science and population genetics studies.

Genetic polymorphism and forensic efficiency of 21 autosomal STR loci from Shandong Han population in Northern China.

BACKGROUND: Highly polymorphic autosomal STR loci are useful for understanding population structure better and for forensic application, however the non-CODIS STR loci in the Han population of Shandong, located in Northern China, are not well-characterised. AIM: To investigate population genetic polymorphism and forensic efficiency of 21 autosomal STR loci from the Shandong Han population in Northern China and reveal the genetic relationships with other populations both at home and abroad. SUBJECTS AND METHODS: In this study, population genetic data of 21 autosomal STR loci included in the Goldeneye DNA ID 22NC Kit that includes four CODIS loci and 17 non-CODIS loci were determined for 523 unrelated Han individuals in Shandong. RESULTS: Significant deviations from Hardy-Weinberg equilibrium were not observed. A total of 233 alleles were detected with allele frequencies ranging from 0.0010 to 0.3728. The combined power of discrimination was 0.99999999999999999999999990011134, and the combined power of exclusion was 0.99999999788131. Furthermore, in an analysis of population differentiation Nei's standard genetic distance and multidimensional scaling analysis, which were conducted based on the overlapping 15 STR loci, revealed that the Shandong Han population was most closely related to populations in close geographic proximity. CONCLUSIONS: This study demonstrated that the 21 autosomal STR loci included in the GoldeneyeTM DNA ID 22NC system are highly polymorphic and suitable for forensic identification and paternity testing in the Shandong Han population. Additionally, the present results enrich the population genetic database.

Verification of a loss of heterozygosity at the D8S1179 locus in a paternity case by the MiSeq FGx system.

Capillary electrophoresis is widely used to study short tandem repeats (STRs) in forensic genetics. However, next-generation sequencing platforms have become a new strategy for forensic DNA typing. In this study, we report a false four-step STR mutation between an alleged father (AF) and child in a paternity case. A total of 23 autosomal STR loci were evaluated using the Huaxia™ Platinum and Goldeneye™ 20A kits, revealing a single mismatch in D8S1179 between the AF (10/10) and the male child (14/14). Additional Y-STR typing of the AF and child was performed, and the results were consistent with those based on 27 Y-STR loci. To further confirm the experimental results, we sequenced the individuals using the MiSeq FGx system and detected 10/15 unbalanced alleles in the D8S1179 locus of the AF and 14/15 unbalanced alleles in the D8S1179 locus of the child. Sanger sequencing revealed that both the AF and child had the C→G point mutation in the primer binding region of D8S1179 resulting in allelic dropout. Therefore, the verification of STR typing by different sequencing systems is helpful for the interpretation of results in cases of multistep STR mutations.

Analysis of five rare alleles at the STR loci D1S1656, D12S391, D13S317, Penta D, and D2S441.

Short tandem repeat (STR) automatic typing technology is extensively used in forensic laboratories with commercial kits, in rare cases genotyping misinterpretations or mislabeling may occur due to unexpected rare alleles. This study refers to the investigation of several rare alleles observed from routine cases. Besides cross-kit verification with Goldeneye 25A (Beijing PeopleSpot Inc, China) and Huaxia platinum (Thermo Fisher Scientific, USA) kits, the next-generation sequencing technology by MiSeq FGx System (Illumina, USA) was applied to further validation. To solve the inconsistent outcomes reached by the above mentioned approaches at D2S441 locus, single gene amplification, gene cloning, and genetic sequencing was also performed. As a result, five rare alleles were detected. Two novel alleles of allele 3 at the D13S317 locus and allele 5 at the D2S441 locus were found; three previously reported alleles of allele 9 at D1S1656 locus, allele 19 at Penta D locus, and allele 28 at D12S391 locus in STRBase were initially supplemented with sequence information. We, therefore, propose that such uncommon observations with rare events should be carefully investigated and interpreted.

A nonautophagic role of ATG5 in regulating cell growth by targeting c-Myc for proteasome-mediated degradation.

Autophagy is a conserved biological process that maintains cell homeostasis by targeting macromolecules for lysosome-mediated degradation. The levels of autophagy are relatively lower under normal conditions than under stress conditions (e.g., starvation), as autophagy is usually stimulated after multiple stresses. However, many autophagy-related regulators are still expressed under normal conditions. Although these regulators have been studied deeply in autophagy regulation, the nonautophagic roles of these regulators under normal conditions remain incompletely understood. Here, we found that autophagy-related 5 (ATG5), which is a key regulator of autophagy, regulates c-Myc protein degradation under normal conditions through the ubiquitin-proteasome pathway. We also found that ATG5 binds c-Myc and recruits the E3 ubiquitin-protein ligase FBW7 to promote c-Myc degradation. Moreover, ATG5-mediated degradation of c-Myc limits cell growth under normal conditions and is essential for embryonic stem cell differentiation. Therefore, this study reveals a nonautophagic role of ATG5 in regulating of c-Myc protein degradation.

The nucleolus functions as the compartment for histone H2B protein degradation.

Histones are main components of chromatin, and the protein levels of histones significantly affect chromatin assembly. However, how histone protein levels are regulated, especially whether and how histones are degraded, is largely unclear. Here, we found that histone H2B is mainly degraded through the proteasome-mediated pathway, and the lysine-120 site of H2B is essential for its K48-linked polyubiquitination and degradation. Moreover, the degradation-impaired H2BK120R mutant shows an increased nucleolus localization, and inhibition of the proteasome results in an elevated nucleolus distribution of wild-type H2B, which is similar to that of H2BK120R mutants. More importantly, the nucleolus fractions can ubiquitinate and degrade the purified H2B in vitro, suggesting that the nucleolus, in addition to its canonical roles regulating ribosome genesis and protein translation, likely associates with H2B degradation. Therefore, these findings revealed a novel mechanism for the regulation of H2B degradation in which a nucleolus-associated proteasome pathway is involved.

Pharmaceutical inhibition of AXL suppresses tumor growth and invasion of esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is a common type of cancer in a number of regions of the world, including East Asia, South Africa and Iran. It is often associated with poor prognosis rates. Tyrosine-protein kinase receptor UFO (AXL) is overexpressed in a subset of ESCC tumors, therefore the present study aimed to determine the effect of R428, a selective inhibitor of AXL, on ESCC tumor cells. TE1 and KYSE150 cell lines were used as models to investigate the effects of R428 treatment. The proliferative rate of the tumor cells was analyzed using MTT and colony formation assays. In addition, cell migration and invasion rates were analyzed using wound healing and Matrigel assays, respectively. The expression levels of matrix metalloproteinase (MMP)2 and MMP9, and the activation of protein kinase B (AKT), extracellular signal-regulated kinase (ERK) and AXL signaling were analyzed using gelatin zymography and western blotting. The results revealed that R428 inhibited the proliferative and invasive abilities of both cell lines. Furthermore, AXL, AKT and ERK signaling were all decreased in response to R428 treatment, alongside the expression levels of MMP2 and MMP9. In conclusion, the results of the present study suggested that R428 treatment may suppress ESCC tumor cell proliferation and invasion, representing a potential therapeutic target for ESCC.

Evaluation of allelic alterations in short tandem repeats in papillary thyroid cancer.

BACKGROUND: Malignant tissue samples may be the only source of biological material for forensic investigations, including individual identification or paternity testing; however, such samples may lead to uncertainties due to frequent genomic aberrations associated with tumors, including alterations of the short tandem repeat (STR) loci used for forensic casework. METHODS: Short tandem repeat loci routinely used in forensic analysis (n = 23) were analyzed in 68 surgically removed papillary thyroid cancer specimens. Tumor cells and normal stromal cells were separated by laser capture microdissection. RESULTS: Four kinds of changes were detected between normal and tumor tissues: partial loss of heterozygosity (pLOH), complete loss of heterozygosity, an additional allele, and a new allele not found in normal tissue. These changes were distributed across 20 of the tested STRs, with no mutations in VWA, D16S539, or Penta D. The most frequently affected locus was D2S1338, and the most frequent type of alteration was pLOH. Samples from patients aged 40-59 years exhibited the highest frequencies of STR variation. CONCLUSION: Our results suggest that great care should be taken in the evaluation of DNA typing results obtained from malignant tissues, particularly when no normal tissue reference samples are available.

Population genetic data from 23 autosomal STR loci of Huaxia Platinum system in the Jining Han population.

BACKGROUND: Genetic polymorphisms at 23 short tandem repeat (STR) loci were investigated in 1,215 Jining Han individuals from Jining city, Shandong province, eastern China. METHODS: We used population genetic data of 23 autosomal STR loci included in the Huaxia Platinum system to evaluate 1,215 unrelated Chinese Han individuals in the Jining Han population. Allele frequencies and forensic parameters of the STR loci were determined and genetic relationships among the Jining Han and other Chinese populations were evaluated. RESULTS: In total, we observed 321 alleles, with frequencies ranging from 0.00041 to 0.52222. The combined discrimination power and probability of excluding paternity were 0.99999999999999999999999999919 and 0.99999999962, respectively. No deviations from HWE were observed at any loci. Population comparisons showed that the Xinjiang groups (Uyghur and Kazakh) and the Mongolian and Tibetan groups were isolated, while the Jining Han population clustered together with other populations, except the Guizhou Han population. CONCLUSION: This study demonstrated that 23 autosomal STR loci included in the Huaxia Platinum system are highly polymorphic and suitable for personal forensic identification and paternity testing in this population.

Epigenetic regulation of ferroptosis by H2B monoubiquitination and p53.

Monoubiquitination of histone H2B on lysine 120 (H2Bub1) is an epigenetic mark generally associated with transcriptional activation, yet the global functions of H2Bub1 remain poorly understood. Ferroptosis is a form of non-apoptotic cell death characterized by the iron-dependent overproduction of lipid hydroperoxides, which can be inhibited by the antioxidant activity of the solute carrier family member 11 (SLC7A11/xCT), a component of the cystine/glutamate antiporter. Whether nuclear events participate in the regulation of ferroptosis is largely unknown. Here, we show that the levels of H2Bub1 are decreased during erastin-induced ferroptosis and that loss of H2Bub1 increases the cellular sensitivity to ferroptosis. H2Bub1 epigenetically activates the expression of SLC7A11. Additionally, we show that the tumor suppressor p53 negatively regulates H2Bub1 levels independently of p53's transcription factor activity by promoting the nuclear translocation of the deubiquitinase USP7. Moreover, our studies reveal that p53 decreases H2Bub1 occupancy on the SLC7A11 gene regulatory region and represses the expression of SLC7A11 during erastin treatment. These data not only suggest a noncanonical role of p53 in chromatin regulation but also link p53 to ferroptosis via an H2Bub1-mediated epigenetic pathway. Overall, our work uncovers a previously unappreciated epigenetic mechanism for the regulation of ferroptosis.

Genetic diversity and haplotype structure of 27 Y-STR loci in a Yanbian Korean population from Jilin Province, Northeast China.

In this study, 27 Y-STRs were analyzed in 347 male individuals from the Yanbian Korean population. Haplotype diversity (HD) and discrimination capacity (DC) values were calculated. Pairwise Rst values were evaluated in AMOVA analysis and visualized through multidimensional scaling (MDS). Yflier Plus system indicated higher Discrimination Power (DP), HD and DC which is 0.9969, 0.9998 and 0.9769. There is no significant genetic distance between Yanbian Koreans and South Koreans, however, there is a great distance from Chinese Han population. The present results may provide useful information for paternal lineages in forensic cases and increase our understanding of the genetic relationships between Yanbian Korean and other groups.

Mechanical stretch and hypoxia inducible factor-1 alpha affect the vascular endothelial growth factor and the connective tissue growth factor in cultured ACL fibroblasts.

PURPOSES: The adult human anterior cruciate ligament (ACL) has poor functional healing response. Hypoxia plays an important role in regulating the microenvironment of the joint cavity after ACL injury, however, its role in mechanical injury is yet to be examined fully in ACL fibroblasts. In this study, we used CoCl2 to induce Hypoxia-inducible factor-1α (HIF-1α) in our experimental model to study its affect on matrix metalloproteinase-2 (MMP-2), vascular endothelial growth factor (VEGF), and connective tissue growth factor (CTGF) expression in ACL fibroblasts after mechanical stretch. MATERIALS AND METHODS: Cell treatments were performed in the stretch chamber in all experimental groups. Quantitative real-time PCR was used to check mRNA expression levels of MMP-2, CTGF, VEGF, and HIF-1α. Western blot was used to detect the HIF-1α production. Enzyme-Linked immunosorbent assay was performed to check the VEGF and CTGF protein contents in supernatant. MMP-2 activity was assayed by gelatin zymography. RESULTS: The real-time PCR results show that mechanical stretch or CoCl2 treatment increases the expression of MMP-2, VEGF, CTGF, and HIF-1α; however, the combined effects of mechanical stretch and CoCl2-induced HIF-1α increased MMP-2 production but decreased the VEGF and CTGF expression, compared to the CoCl2 treatment group alone. Western blot analysis and ELISA also confirmed these results. CONCLUSIONS: Our results demonstrated that mechanical stretch and CoCl2-induced HIF-1α together increased the level of MMP-2 and decreased the levels of VEGF and CTGF in cultured ACL fibroblasts. The differential expression and production of HIF-1α, VEGF, MMP-2, and CTGF might help to explain the poor healing ability of ACL.

[Application of a new design of cryo-jaw and its biomechanical evaluation in rat achilles tendon in vitro].

This study was aimed to design a new, accurate and easy-to-use water bath cryo-jaw, and try to solve the problems met in small animals achilles tendon mechanical testing. The muscle-tendon-bony units were fixed in the clamps. SD rats achilles tendon were randomly divided into group A and B. Group A was tested by the newly designed water bath cryo-jaw, while group B was treated by non-water bath cryo-jaw. The mechanical tests revealed that non of the samples of the newly-designed water bath cryo-jaw in group A slipped and fell off, and the achilles tendons were in a physiologically active state, but one of the group B samples slipped and fell off, and the others had the frozen phenomenon obviously. The maximum stress, fracture displacement and Young's modulus of the rats in group A were significantly different compared to those in group B (P < 0.05). In conclusion, the new water bath cryo-jaw has more advantages than traditional ones. It exhibits a good simulation in vivo in the environmental conditions for testing the mechanical properties of the achilles tendon.

Magnetic bead-based separation of sperm from buccal epithelial cells using a monoclonal antibody against MOSPD3.

Forensic DNA analysis of sexual assault evidence requires unambiguous differentiation of DNA profiles in mixed samples. To investigate the feasibility of magnetic bead-based separation of sperm from cell mixtures using a monoclonal antibody against MOSPD3 (motile sperm domain-containing protein 3), 30 cell samples were prepared by mixing 10(4) female buccal epithelial cells with sperm cells of varying densities (10(3), 10(4), or 10(5) cells/mL). Western blot and immunofluorescence assays showed that MOSPD3 was detectable on the membrane of sperm cells, but not in buccal epithelial cells. After biotinylated MOSPD3 antibody was incubated successively with the prepared cell mixtures and avidin-coated magnetic beads, microscopic observation revealed that each sperm cell was bound by two or more magnetic beads, in the head, neck, mid-piece, or flagellum. A full single-source short tandem repeat profile could be obtained in 80% of mixed samples containing 10(3) sperm cells/mL and in all samples containing ≥10(4) sperm cells/mL. For dried vaginal swab specimens, the rate of successful detection was 100% in both flocked and cotton swabs preserved for 1 day, 87.5% in flocked swabs and 40% in cotton swabs preserved for 3 days, and 40% in flocked swabs and 16.67% in cotton swabs preserved for 10 days. Our findings suggest that immunomagnetic bead-based separation is potentially a promising alternative to conventional methods for isolating sperm cells from mixed forensic samples.

Human iPSC-derived neural crest stem cells promote tendon repair in a rat patellar tendon window defect model.

Induced pluripotent stem cells (iPSCs) hold great potential for cell therapy and tissue engineering. Neural crest stem cells (NCSCs) are multipotent that are capable of differentiating into mesenchymal lineages. In this study, we investigated whether iPSC-derived NCSCs (iPSC-NCSCs) have potential for tendon repair. Human iPSC-NCSCs were suspended in fibrin gel and transplanted into a rat patellar tendon window defect. At 4 weeks post-transplantation, macroscopical observation showed that the repair of iPSC-NCSC-treated tendons was superior to that of non-iPSC-NCSC-treated tendons. Histological and mechanical examinations revealed that iPSC-NCSCs treatment significantly enhanced tendon healing as indicated by the improvement in matrix synthesis and mechanical properties. Furthermore, transplanted iPSC-NCSCs produced fetal tendon-related matrix proteins, stem cell recruitment factors, and tenogenic differentiation factors, and accelerated the host endogenous repair process. This study demonstrates a potential strategy of employing iPSC-derived NCSCs for tendon tissue engineering.

Differential response to CoCl2-stimulated hypoxia on HIF-1α, VEGF, and MMP-2 expression in ligament cells.

The adult human anterior cruciate ligament (ACL) has a poor functional healing response, whereas the medial collateral ligament (MCL) does not. The difference in intrinsic properties of these ligament cells can be due to their different response to their located microenvironment. Hypoxia is a key environmental regulator after ligament injury. In this study, we investigated the differential response of ACL and MCL fibroblasts to hypoxia on hypoxia-inducible factor-1α, vascular endothelial growth factor, and matrix metalloproteinase-2 (MMP-2) expression. Our results show that ACL cells responded to hypoxia by up-regulating the HIF-1α expression significantly as compared to MCL cells. We also observed that in MCL fibroblasts response to hypoxia resulted in increase in expression of VEGF as compared to ACL fibroblasts. After hypoxia treatment, mRNA and protein levels of MMP-2 increased in both ACL and MCL. Furthermore we found in ACL pro-MMP-2 was converted more into active form. However, hypoxia decreased the percentage of wound closure for both ligament cells and had a greater effect on ACL fibroblasts. These results demonstrate that ACL and MCL fibroblasts respond differently under the hypoxic conditions suggesting that these differences in intrinsic properties may contribute to their different healing responses and abilities.

Combined effects of TNF-α, IL-1ß, and HIF-1α on MMP-2 production in ACL fibroblasts under mechanical stretch: an in vitro study.

The dynamics between inflammatory factors, mechanical stress, and healing factors, in an intra-articular joint, are very complex after injury. Injury to intra-articular tissue [anterior cruciate ligament (ACL), synovium] results in hypoxia, accumulation of various pro-inflammatory factors, cytokines, and metalloproteases. Although the presence of increased amounts of matrix-metalloproteinases (MMP) in the joint fluid after knee injury is considered the key factor for ACL poor healing ability; however, the exact role of collective participants of the joint fluid on MMP-2 activity and production has not been fully studied yet. To investigate the combined effects of mechanical injury, inflammation and hypoxia induced factor-1α (HIF-1α) on induction of MMP-2; we mimicked the microenvironment of joint cavity after ACL injury. The results show that TNF-α and IL-1ß elevate the activity of MMP-2 in a dose- and time-dependent manner. In addition, mechanical stretch further enhances the MMP-2 protein levels with TNF-α, IL-1ß, and their mixture. CoCl(2) -induced HIF-1α (100 and 500 µM) also increases the levels and activity of MMP-2. Mechanical stretch has a strong additional effect on MMP-2 production with HIF-1α. Our results conclude that mechanical injury, HIF-1α and inflammatory factors collectively induce increased MMP-2 production in ACL fibroblasts, which was inhibited by NF-κB pathway inhibitor (Bay-11-7082).

TGF-ß1 promoted MMP-2 mediated wound healing of anterior cruciate ligament fibroblasts through NF-κB.

The adult human anterior cruciate ligament (ACL) has poor functional healing response. Transforming growth factor (TGF)-ß1 enhances the wound repair by stimulating matrix proteins deposition as well as the proliferation and migration of cells. However, the function of the TGF-ß1-induced matrix metalloproteinases' (MMPs) activities in the wound healing process is poorly understood. In this study, exogenous MMP-2 is added to mimic the TGF-ß1-induced MMP-2 expression. Role of NF-κB pathway is further examined. Our results show that TGF-ß1 induces dramatic elevation of MMP-2 activities and the MMP-2/tissue inhibitors of metalloproteinases ratio. Furthermore, the exogenous MMP-2 significantly promoted in vitro wound healing abilities of ACL fibroblasts that are significantly blocked with the addition of its inhibitors. TGF-ß1 also increases the proliferation of ACL fibroblasts whereas MMP-2 alone does not, indicating that MMP-2 activities are not involved in the proliferation. TGF-ß1-induced MMP-2 activity is inhibited by Bay11-7082 and Bay11-7085 (NF-κB inhibitors). Our results demonstrate that increased TGF-ß1 facilitates the ACL healing process by promoting the fibroblasts migration and proliferation. The migration process is mediated by MMP-2 and NF-κB pathway is involved in TGF-ß1-mediated MMP-2 release.