USP4 promotes PTC progression by stabilizing LDHA and activating the MAPK and AKT signaling pathway.

Ubiquitin-specific protease 4 (USP4) has been identified as a promising oncogenic factor implicated in various human malignancies. However, the exact biological functions and underlying mechanisms of USP4 in the progression of papillary thyroid carcinoma (PTC) remain elusive. In this study, we observed a marked upregulation of USP4 expression in PTC tumor tissues. Elevated levels of USP4 were significantly correlated with aggressive clinicopathological features and poor prognosis. Functional assays for loss-of-function demonstrated that silencing USP4 hindered the proliferation of PTC cells. Furthermore, our investigation revealed a specific interaction between USP4 and lactate dehydrogenase A (LDHA), wherein USP4 played a crucial role in stabilizing LDHA protein levels via deubiquitination in PTC cells. Notably, this study demonstrated that USP4 promotes PTC proliferation by modulating the MAPK and AKT signaling pathways. In summary, our findings elucidate the critical involvement of the USP4/LDHA axis in driving PTC progression through the modulation of MAPK and AKT pathways, thereby identifying USP4 as a potential therapeutic target for the treatment of PTC.

Circ_0084653 promotes the tumor progression and immune escape in triple-negative breast cancer via the deubiquitination of MYC and upregulation of SOX5.

The role of circular RNAs (circRNAs) in cancers is gaining more and more attention, yet related reporters are limited. In triple-negative breast cancer (TNBC), circRNA circ_0084653 originated from COP9 signalosome subunit 5 (COPS5), and COPS5 has been validated to be upregulated in breast cancer before. In our research, COPS5 was also upregulated in TNBC cells, and knockdown of it repressed cell proliferation, invasion, EMT, stemness and PDL-1 protein expression but increased T-cell percentage. Further, circ_0084653 was an aberrantly upregulated circRNA in TNBC cells, and similarly, circ_0084653 silence inhibited TNBC development. Besides, circ_0084653 expression was distributed in both cytoplasm and nucleus. COPS5 overexpression partially rescued the suppressing effects of circ_0084653 depletion in TNBC. Subsequently, circ_0084653 triggered deubiquitination of MYC, the upstream transcription factor of COPS5, via recruiting ubiquitin specific peptidase 36 (USP36). Moreover, circ_0084653 served as the sponge of miR-1323 to release the expression the target gene SRY-box transcription factor 5 (SOX5). SOX5 upregulation completely remedied the inhibiting influence of circ_0084653 downregulation in TNBC. Meanwhile, transcription factor SOX5 activated transcriptionally circ_0084653. To sum up, SOX5-induced circ_0084653 promotes TNBC via the deubiquitination of USP36, which may provide some fresh ideas for TNBC-related molecular mechanisms.

Improved complete ensemble empirical mode decomposition with adaptive noise and composite multiscale permutation entropy for denoising blast vibration signal.

Monitoring the building blast vibration signal is an efficient way to determine the power of blast vibration hazards. Due to the harsh measurement environment, noise is inevitably introduced into the recorded signals. This research presents a denoising approach based on Improved complete ensemble empirical mode decomposition with adaptive noise(ICEEMDAN) and Composite Multiscale Permutation Entropy (CMPE). First, the noisy blast vibration signal is decomposed into different intrinsic mode functions using ICEEMDAN; then multiple intrinsic mode functions (IMFs) are separated into pure and noisy using CMPE, the noisy IMFs are denoised using wavelet thresholding; finally the blast wave is reconstructed using the pure and denoised mixed IMFs. The proposed approach was compared with four other approaches (CEEMDAN-CMPE, VMD-CMPE, SVMD-CMPE, and WST). The results indicate that the proposed approach has better performance and can be considered as an effective denoising method for building blast vibration signals.

Study on the Influence of Temperature and Water Content on the Static Mechanical Properties of Sandstone.

The area of permafrost worldwide accounts for approximately 20% to 25% of land area. In cold-climate regions of China, which are garnering international attention, the study of low-temperature and moisture effects on rock mass mechanical properties is of significant importance. China has a wide area of cold regions. This research can provide a foundation for China's exploration activities in such extreme environments. This paper examines the mechanical behavior of rock specimens subjected to various low temperatures and water contents through uniaxial compression tests. The analysis encompasses failure modes, stress-strain relationships, uniaxial compressive strength (UCS), and elastic modulus (EM) of these specimens. Findings reveal that at lower temperatures, the rock specimens' fracture patterns transition from compressive shear failure to cleavage failure, reflecting a shift from a plastic-elastic-plastic to a plastic-elastic response. Specifically, saturated rocks exhibit a 40.8% decrease in UCS and an 11.4% reduction in EM compared to their dry counterparts. Additionally, in cold conditions, an increased water content in rocks primarily leads to vertical cracking. Under such conditions, saturated rocks show a 52.3% decline in UCS and a 15.2% reduction in EM, relative to their dry state.

Micro- and Mesoporous Structural Effects of Beta Zeolites for Volatile Organic Compound Sorption.

To fully exploit pore engineering in the design of more efficient zeolite adsorbents for volatile organic compound (VOC) treatment, the roles of meso- and micropores need to be clarified to provide the theoretical basis and feasible measures. In this work, the three VOC sorption properties of conventional and hierarchical porous beta zeolites were comparatively investigated to study the roles of meso- and micropores. There is a division of functions between micro- and mesopores, with micropores being the main VOC adsorption sites and mesopores greatly enhancing VOC diffusion and adsorbent reusability. On the one hand, micropores should be preserved as much as possible because obtaining mesopores by sacrificing micropores (i.e., alkali treatment) results in 28-60% decreases in adsorption capacities. On the other hand, mesopore introduction is highly desirable, which results in an enhancement of VOC intraparticle diffusion rates by 1.3-2.3 times (at the VOC concentration of 600 ppm) and chlorobenzene adsorption capacity on the 20th cycle increasing from 78% of the initial value to 89 and 93%. The findings may provide valuable information about zeolite-based adsorbents for adsorption removal or recovery of VOCs.

Preparation of nano-MFI zeolites doped with Al/Ti and their performance in VOC sorption.

Highly crystalline nano-MFI-type zeolites containing different elements were synthesized, and the sorption effects of the elements on volatile organic compounds (VOCs) were investigated. The results showed that the optimal toluene and acetone breakthrough time of the synthesized zeolites was 2.1 and 1.9 times as long as that of the commercial zeolite, respectively. For a weakly polar toluene molecule, MFI zeolites (aluminum-free) showed better adsorption properties than aluminum-containing zeolites. For the highly polar acetone molecule, zeolites with a Si/Al ratio of 87 showed the highest adsorption capacity, which was 7% higher than that of the all-silica zeolite and 1.4 times that of the commercial zeolite. Furthermore, MFI zeolites with Ti replacing part of Al proved to have better performance for highly polar molecules. In the adsorption process of VOCs, in addition to internal diffusion, diffusion on the external surface of the zeolite also played a remarkable role, and the adsorption data of all samples fitted better with the pseudo-first-order model. This study may provide a reliable structure-performance relationship for the synthesis of nanosized zeolite-based adsorbents and their use in the industrial recovery/treatment of VOCs.

Testing and Analysis of Ultra-High Toughness Cementitious Composite-Confined Recycled Aggregate Concrete under Axial Compression Loading.

In order to analyze the axial compressive properties of ultra-high-toughness cementitious composite (UHTCC)-confined recycled aggregate concrete (RAC), a batch of UHTCC-confined RAC components was designed and manufactured according to the requirements of GB/T50081-2002 specifications. After analyzing the surface failure phenomenon, load-displacement curves, scanning electron microscope (SEM), and parameter analysis of the specimen, the result shows that UHTCC-confined RAC is an effective confinement method, which can effectively improve the mechanical properties and control the degree of surface failure of RAC structures. Compared with the unconfined specimen, the maximum peak load of the UHTCC confinement layer with a thickness of 10 mm and 20 mm increased by 44.61% and 79.27%, respectively, meeting the requirements of engineering practice. Different fiber mixing amounts have different effects on improving the mechanical performance of RAC structural. The specific rule was steel fiber (SF) > polyvinyl alcohol fiber (PVAF) > polyvinyl alcohol fiber (PEF) > no fiber mixture, and the SF improves the axial compression properties of UHTCC most significantly. When there are strict requirements for improving the mechanical properties of the structure, SF should be added to UHTCC. On the contrary, PVAF should be added to UHTCC.

The mixed subtype has a worse prognosis than other histological subtypes: a retrospective analysis of 217 patients with metaplastic breast cancer.

OBJECTIVE: Metaplastic breast cancer (MpBC) is an aggressive subtype of all breast cancer. We aimed to investigate the clinicopathological features, treatments and prognoses of MpBC patients. METHODS: We collected the data from MpBC patients diagnosed at Tianjin Medical University Cancer Hospital from 2010 to 2017. Kaplan Meier curves and Cox regression model were used to evaluating clinical outcomes and prognostic factors. After removing baseline differences by propensity score matching (PSM), we analyzed the prognosis between MpBC patients and invasive ductal carcinomas of no special type (IDC-NST) patients. RESULTS: A total of 217 MpBC patients were subsumed. Of all histological subtypes, 45.1% were mixed subtypes, followed by with mesenchymal differentiation (27.2%), pure squamous (15.2%) and pure spindle (12.4%) subtypes. 69.6% of MpBC were triple-negative, 25.3% and 6.5% were HR-positive and HER2-positive. MpBC patients had worse survival compared to IDC-NST patients, with 5-year RFS of 73.8 and 83.6% (HR = 1.177 95%CI (1.171-2.676) P = 0.0068), and 5-year BCSS of 79.0% and 89.7% (HR = 2.187 95%CI (1.357-3.523) P = 0.0013). In the multivariate COX model, AJCC stage, mixed subtype and chemotherapy were independent prognostic factors. Mixed MpBC is more aggressive than pure and with heterologous mesenchymal differentiation subtypes. And whether squamous or spindle MpBC, mixed forms have shorter outcomes than pure forms. CONCLUSIONS: MpBCs are associated with poorer prognoses than IDC-NSTs. They are heterogeneous with different clinicopathological features and clinical outcomes between histological subtypes. Pure and with heterologous mesenchymal differentiation subtypes have more survival benefits than the mixed subtype.

Theoretical study on structural and mechanical properties of Si-containing ternary transition metal nitrides M0.5Si0.5N (M = Ti, Zr, Hf).

Si-containing transition-metal nitrides Ti0.5Si0.5N, Zr0.5Si0.5N and Hf0.5Si0.5N with conventional rock salt B1 structure exhibit superior hardness, strength and oxidation resistance. However, the potential phases of the ternary systems at various pressures remain unexplored. In this work, we firstly studied the potential structures of Ti0.5Si0.5N, Zr0.5Si0.5N and Hf0.5Si0.5N in pressures of 0-100 GPa. A hexagonal phase with P63/mmc symmetry was uncovered and verified to be quenchable in the ambient conditions. The structural, mechanical and electronic properties were systematically studied and compared with the well-known ordered B1 structure. We surprisingly found that Ti0.5Si0.5N within this hexagonal phase displayed much improved ideal indentation shear strength from about 10 GPa for a B1 structure to 30 GPa. The estimated hardness based on the empirical formula is up to 38 GPa, greatly exceeding that of the B1 structure. By the detailed electronic analysis, the underlying atomic mechanism for the outstanding mechanical properties was also studied.

Cryogel-Templated Fabrication of n-Al/PVDF Superhydrophobic Energetic Films with Exceptional Underwater Ignition Performance.

The rapid heat loss and corrosion of nano-aluminum limits the energy performance of metastable intermolecular composites (MICs) in aquatic conditions. In this work, superhydrophobic n-Al/PVDF films were fabricated by the cryogel-templated method. The underwater ignition performance of the energetic films was investigated. The preparation process of energetic materials is relatively simple, and avoids excessively high temperatures, ensuring the safety of the entire experimental process. The surface of the n-Al/PVDF energetic film exhibits super-hydrophobicity. Because the aluminum nanoparticles are uniformly encased in the hydrophobic energetic binder, the film is more waterproof and anti-aging. Laser-induced underwater ignition experiments show that the superhydrophobic modification can effectively induce the ignition of energetic films underwater. The results suggest that the cryogel-templated method provides a feasible route for underwater applications of energetic materials, especially nanoenergetics-on-a-chip in underwater micro-scale energy-demanding systems.

In Vitro and in Vivo Study of the Effect of Osteogenic Pulsed Electromagnetic Fields on Breast and Lung Cancer Cells.

Introduction: Although there have been significant advances in research and treatments over the past decades, cancer remains a leading cause of morbidity and mortality, mostly due to resistance to standard therapies. Pulsed electromagnetic field (PEMF), a newly emerged therapeutic strategy, has been highly regarded as less invasive and almost safe to patients, is now a clinically accepted form to treat diseases including cancer. Breast and lung cancer are the most prevalent forms of human cancers, yet reported investigations on exploring regimes including PEMF are limited. Methods: Intended to examine the anti-tumor effects of a clinically accepted osteogenic PEMF and the possibility of including PEMF in breast and lung cancer treatments, we studied the effects of 2 PEMF signals (PMF1 and PMF2) on breast and lung cancer cell growth and proliferation, as well as the possible underline mechanisms in vitro and in vivo. Results: We found that both signals caused modest but significant growth inhibition (∼5%) in MCF-7 and A549 cancer cells. Interestingly, mice xenograft tumors with A549 cells treated by PEMF were smaller in sizes than controls. However, for mice with MCF-7 tumor implants, treatment with PMF1 resulted in a slight increase (2.8%) in mean tumor size, while PMF2 treated tumors showed a 9% reduction in average size. Furthermore, PEMF increased caspase 3/7 expression levels and percentage of annexin stained cells, indicating the induction of apoptosis. It also increased G0 by 8.5%, caused changes in the expression of genes associated with cell growth suppression, DNA damage, cell cycle arrest, and apoptosis. When cancer cells or xenograft tumors treated with combined PEMF and chemotherapy drugs, PEMF showed growth inhibition effect independent of cisplatin in A549 cells, but with added effect by pemetrexed for the inhibition of MCF-7 growth. Conclusion: Together, our data suggested that clinically used osteogenic PEMF signals moderately suppressed cancer cell growth and proliferation both in vitro and in vivo.

Whole-genome bisulfite sequencing analysis of circulating tumour DNA for the detection and molecular classification of cancer.

BACKGROUND: Cancer cell-specific variation and circulating tumour DNA (ctDNA) methylation are promising biomarkers for non-invasive cancer detection and molecular classification. Nevertheless, the applications of ctDNA to the early detection and screening of cancer remain highly challenging due to the scarcity of cancer cell-specific ctDNA, the low signal-to-noise ratio of DNA variation, and the lack of non-locus-specific DNA methylation technologies. METHODS: We enrolled three cohorts of breast cancer (BC) patients from two hospitals in China (BC: n = 123; healthy controls: n = 40). We developed a ctDNA whole-genome bisulfite sequencing technology employing robust trace ctDNA capture from up to 200 µL plasma, mini-input (1 ng) library preparation, unbiased genome-wide coverage and comprehensive computational methods. RESULTS: A diagnostic signature comprising 15 ctDNA methylation markers exhibited high accuracy in the early (area under the curve [AUC] of 0.967) and advanced (AUC of 0.971) BC stages in multicentre patient cohorts. Furthermore, we revealed a ctDNA methylation signature that discriminates estrogen receptor status (Training set: AUC of 0.984 and Test set: AUC of 0.780). Different cancer types, including hepatocellular carcinoma and lung cancer, could also be well distinguished. CONCLUSIONS: Our study provides a toolset to generate unbiased whole-genome ctDNA methylomes with a minimal amount of plasma to develop highly specific and sensitive biomarkers for the early diagnosis and molecular subtyping of cancer.

Experimental study on compression mechanical characteristics of filled rock joints after multiple pre-impacts.

The prefabricated artificial filled jointed rock specimens are impacted by a self-made drop hammer impact device for many times, and the specimens with different degrees of cumulative damage characteristics are obtained. Then, the static and dynamic compression mechanical properties are studied by using universal testing machine and SHPB device. Through the static compression test, the strength and deformation characteristics of jointed rock specimens after multiple impacts are obtained, and the influence of the damage degree of jointed rock specimens characterized by wave velocity on the compressive strength of filled joints is analysed. Based on the results of SHPB impact test, the dynamic strength and deformation evolution, wave propagation law and energy dissipation law of filled joints after multiple impacts are analysed. During the SHPB test, the impact failure process of rock specimens is recorded by a high-speed camera. The experimental results show that the damage degree of jointed rock samples increases nonlinearly after multiple impacts. The attenuation laws of static strength and dynamic strength of rock samples under the same damage evolution conditions are different. With the increase of impact times, the failure mode of jointed rock samples after damage is simpler and tends to compression failure.

Analysis of Clinical Characteristics, Treatment, and Prognostic Factors of 106 Breast Cancer Patients With Solitary Pulmonary Nodules.

OBJECTIVE: The clinical features of solitary pulmonary nodules (SPN) in breast cancer patients were retrospectively analyzed, and the clinical features of primary lung cancer (PLC) and metastatic pulmonary breast cancer (MBC) in breast cancer patients were compared, and the treatment plan, curative effect and influencing factors were analyzed. METHODS: The clinical data of 106 patients of SPN combined with breast cancer surgery in our hospital from January 2015 to June 2020 were analyzed. There were 65 patients of PLC and 41 patients of MBC. Record the characteristics of the primary breast cancer lesion in our patient, the interval between the initial diagnosis of breast cancer and the appearance of SPN, the previous treatment history of our patient, and the characteristics and surgical method of SPN. The survival status of all patients during the follow-up period was recorded. RESULTS: The onset age, interval, maximum nodule diameter, ER expression positive rate and radiotherapy history ratio of PLC patients were higher than those of MBC patients, and the lymph node positive rate and triple negative rate were lower than those of MBC patients (P < 0.05). Median survival was 51 months in patients with PLC and 37 months in patients with MBC. The 1, 3, and 5 year overall survival rates in patients with PLC were higher than those in patients with MBC (P < 0.05). Vascular tumor thrombus, SPN type and chemotherapy were all independent factors affecting the prognosis of patients with breast cancer combined with SPN (P < 0.05). CONCLUSION: PLC patients and MBC patients have significant differences in pathological characteristics, like the onset age, interval, maximum nodule diameter, ER expression positive rate, radiotherapy history ratio, the lymph node positive rate, and triple negative rate. Septum, vascular tumor thrombus, SPN type, and chemotherapy are all independent factors that affect the curative effect of breast cancer patients with SPN. Based on the nature of SPN, it can provide reference for clinicians to decide the treatment plan, improve patients' quality of life and prolong their survival time.

Tensile Properties and Fracture Mechanism of Thermal Spraying Polyurea.

In this study, polyurea was experimentally tested under various spraying temperatures and pressures. The number of holes and the pore size produced after the tensile fracture of the polyurea were counted to illustrate the effect of the various spraying temperatures and pressures on the performance of the polyurea. The tensile characteristics of polyurea were greatly influenced by the spraying temperatures and pressures, according to the experimental findings and statistical analysis. The polyurea tensile performance was best when the spraying pressure was 17.25 MPa with a spraying temperature of 70 °C. The fracture mechanism was illustrated by the silver streaking phenomenon generated during the tensile stretching process. The fracture energy was absorbed by the fracture holes and pores during silver streaking, thus creating the huge gap in tensile properties.

Tolerance and Pharmacokinetics of Recombinant Human Endostatin Administered as Single-Dose or Multiple-Dose Infusions in Patients With Advanced Solid Tumors: A Phase I Clinical Trial.

Objective: This study aimed to investigate the tolerance and pharmacokinetic characteristics of recombinant human endostatin (rh-endostatin) administered as single-dose or multiple-dose infusions in patients with advanced solid tumors. Methods: This phase I trial was designed as a single-center, single-arm, nonrandomized, open-label, dose-escalation study. The trial consisted of 2 parts: a single-dose part and a multiple-dose part, each with 3 dose comparison groups. Rh-endostatin was administered as an intravenous injection only once at a dose of 5 mg/m2, 7.5 mg/m2, or 10 mg/m2 in the single-dose part and as a daily intravenous injection for 14 days at the same doses in the multiple-dose part. The serum pharmacokinetics, toxicity and immunogenicity of rh-endostatin were evaluated. Results: Dose-limiting toxicity (DLT) was not observed in any group. A few patients developed cardiotoxicity, such as QT prolongation or narrow arrhythmia. Other adverse events were slight coagulation abnormalities and haematological abnormalities. For rh-endostatin doses of 5 mg/m2, 7.5 mg/m2, and 10 mg/m2, the mean Cmax values in the single-dose part were 344 ± 38.7 ng/mL, 524 ± 157 ng/mL, and 800 ± 201 ng/mL, respectively, and the average AUC0-t values were 3290 ± 3790 ng•h/mL, 4940 ± 4380 ng•h/mL, and 5050 ± 3980 ng•h/mL, respectively. The Cmax ss values of the 3 doses in the multiple-dose part were 575 ± 270 ng/mL, 531 ± 106 ng/mL, and 864 ± 166 ng/mL, respectively, and the AUC0-τ values were 3610 ± 1040 ng•h/mL, 3290 ± 1090 ng•h/mL, and 5180 ± 1210 ng•h/mL, respectively. The Cmax of a single-dose regimen showed linear kinetic characteristics. The patients in the single-dose group were negative for serum antibodies against rh-endostatin, while one patient in the multiple-dose group was positive. Conclusions: Rh-endostatin as a daily intravenous injection for 14 days in patients with advanced solid tumors is safe and well tolerated, without DLT, at doses of 5 mg/m2, 7.5 mg/m2, and 10 mg/m2. Serum antibodies against rh-endostatin were very low after multiple infusions. For phase II trials, the recommended rh-endostatin dose is 10 mg/m2 as a daily intravenous injection for 14 days.

Visualization of Combustion Phases of Biomass Particles: Effects of Fuel Properties.

This work established a high-speed camera-assisted visualization system that investigated the effect of volatile matter and fixed carbon content in biomass particles on single-particle combustion phases and their luminous properties. Three types of biomass particles, namely, sawdust (a mixture of pine and willow), corncob, and rice husk, were examined on a Hencken flat-flame burner. The luminous region and intensity of single biomass particles were closely related to the flammability and calorific value of biomass fuel and derived by analyzing a sequence of images captured using a high-speed camera. The combustion temperature was determined through analysis of its radiant energy. The results showed that the ignition mechanisms of volatile matter and fixed carbon corresponded to homogeneous and heterogeneous reactions, respectively. The maximum luminous region values of 1.75 × 106, 2.1 × 106, and 1.0 × 106 µm2 for sawdust (SD), corncob (CC), and rice husk (RH) correlated to the volatile matter content of each biomass sample, which was 69.38, 74.15, and 64.56%, respectively. Because of the high fixed carbon content, the peak temperature of the SD particles could reach 1549 °C. The luminous region and intensity of the combusting particles were significantly affected by the volatile matter and fixed carbon, respectively.

Metastasis patterns and prognosis in breast cancer patients aged ≥ 80 years: a SEER database analysis.

Background: This study aimed to investigate the metastasis patterns and prognosis of breast cancer (BC) in patients aged ≥ 80 years with distant metastases, as the current literature lacks studies in this population. Methods: A retrospective, population-based study using data from the Surveillance, Epidemiology, and End Results (SEER) database was conducted to evaluate 36,203 patients with BC from 2010 to 2016. Patients were classified into three groups, the older group (aged ≥ 80 years), middle-aged group (aged 60-79 years), and younger group (aged < 60 years). The role of age at the time of BC diagnosis in metastasis patterns was investigated, and the survival of different age groups of patients with BC was assessed. Results: Overall, 4,359 (12%) patients were diagnosed with BC at age ≥ 80 years, 19,688 (54%) at 60-79 years, and 12,156 (34%) at < 60 years. Compared with the other two groups, those in the older group had a lower rate of treatment acceptance. Statistical analysis revealed that older patients were more likely to have lung invasion only (odds ratio [OR]: 1.274, 95% confidence interval [CI]: 1.163-2.674) and less likely to have bone invasion only (OR: 0.704, 95% CI: 0.583-0.851), brain invasion only (OR: 0.329, 95% CI: 0.153-0.706), or multiple metastatic sites (OR: 0.361, 95% CI: 0.284-0.458) compared to the other two groups. Age at diagnosis was an independent prognostic factor for survival. The older group had the worst overall survival (OS, P<0.001) and BC-specific survival (CSS, P<0.001). Furthermore, patients aged ≥ 80 years with only liver metastasis had the worst CSS and OS. Conclusion: Patients aged ≥ 80 years were less likely to be receptive to cancer-related therapy and had the highest cancer mortality rate among all patients. Our findings will hopefully help clinicians develop more appropriate modalities of cancer treatment in elderly BC patients.

Co-cultivation of progenitor cells enhanced osteogenic gene expression and angiogenesis potential in vitro.

OBJECTIVES: The efficiencies of osteogenesis and angiogenesis present challenges that need to be overcome before bone tissue engineering can be widely applied to clinical uses. We aimed to optimize an in vitro culture system to enhance osteogenesis and angiogenesis. We investigated if hematopoietic stem cells (HSCs) promoted osteogenesis in vitro when co-cultured with mesenchymal stem cells (MSCs) and endothelial progenitor cells (EPCs). METHODS: MSC/HSC, MSC/EPC/HSC, and MSC/EPC co-cultures were incubated for 21 days. Alkaline phosphatase (ALP) activity and calcium content were analyzed to assess mineralization. Expression levels of genes encoding osteogenesis-related proteins (ALP (ALPL), collagen type IA (COL1A1), osteocalcin (BGLAP), and osteopontin (OSTP)) were also evaluated by measuring mRNA levels at day 28. Angiogenesis was evaluated by tube-formation assay. RESULTS: COL1A1, OSTP, ALPL, and BGLAP genes were upregulated in MSC/HSC and MSC/EPC/HSC co-cultures compared with the MSC/EPC group. Upregulation was strongest in the MSC/EPC/HSC co-cultures. There were no significant changes in ALP levels and calcium content, but ALP activity was slightly higher and calcium content was relatively lower in the MSC/EPC and MSC/EPC/HSC groups. CONCLUSIONS: Co-culture of MSCs with HSCs or EPCs/HSCs upregulated the expression of osteogenesis-related genes but did not affect the efficiency of osteogenesis.