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Xiaobo Chen

Publications and source records attributed to Xiaobo Chen.

9 recordsLinked to original sources
PubMed2026

The molecular similarity landscape of preclinical cancer models to patient tumors.

Selecting appropriate preclinical models is fundamental for translational oncology, yet a large-scale, multi-omic quantitative comparison of their similarity to primary human tumors is lacking. To address this, we integrated transcriptomic, proteomic, and genomic profiles from over 10,000 primary tumors from The Cancer Genome Atlas (TCGA) and the Clinical Proteomic Tumor Analysis Consortium (CPTAC), alongside 4,000 preclinical models. Using a robust computational framework, we revealed a clear hierarchy of transcriptomic and proteomic similarity to patient tumors: with patient-dervied xenografts (PDXs) having greater transcriptomic and proteomic similarity to patient tumors (>) compared with patient-derived organoids (PDOs), which are equal in hierarchy to that of PDX-dervied organoids (PDXOs) > cell lines. We also quantified high molecular conservation (Pearson correlation coefficient = 0.96) across paired in vitro to in vivo platform (organoids to PDX) transitions. Furthermore, genomic analysis demonstrated that whole-exome sequencing (WES) outperforms RNA-seq in detecting DNA variants, and it identified a clonal complexity hierarchy (cell lines > PDXOs > PDXs > PDOs) reflecting the effect of passaging history on intratumor heterogeneity. Ultimately, this study delivers a comprehensive quantitative benchmark, establishing a population-level hierarchy of molecular similarity between preclinical models and primary tumors and providing a data-driven reference for model selection. These findings offer a data-driven framework for selecting models that balance biological representativeness with experimental practicality.

Humans↗
PubMed2006

Synthesis of titanium dioxide (TiO2) nanomaterials.

Titanium dioxide (TiO2) is a promising material for many emerging applications. Even more promising are the benefits offered by the material when its length scale is reduced to the nanometer range. Nanomaterials usually exhibit unique properties resulting from either the extremely large surface area-to-volume ratio or the quantum confinement effect of energy carriers. In this article we present an overview of recent progress in the synthesis of TiO2 nanomaterials. The topics include synthesis of TiO2 nanoparticles, nanorods, nanowires, nanotubes, and mesoporous/nanoporous materials using different preparation approaches such as sol-gel, sol, hydrothermal, solvothermal, and vapor deposition. The applications of TiO2 nanomaterials are also briefly summarized.

Biocompatible Materials↗
PubMed2005

Investigation of the crystallization process in 2 nm CdSe quantum dots.

Investigation of the growth of CdSe nanocrystals ( approximately 160 atoms) to the uniquely stable size of 2 nm allows the monitoring of the crystallization process in semiconductor quantum dots. By using a combination of optical techniques, high-resolution transmission electron microscopy (HRTEM), and powder X-ray diffractometry (XRD), new phenomena were explored during the CdSe nanocrystal growth process, which involved significant morphological reconstruction and crystallization of the initially formed amorphous nanoparticles. During the crystallization, the absorption onset of the CdSe quantum dots blue shifted toward higher energies at 3 eV (414 nm), while the photoluminescence red shifted to lower energies. Furthermore, an apparent increasing Stokes shift was observed during the formation of small CdSe nanoparticles. On the other hand, the photoluminescence excitation spectra showed constant features over the reaction time. Additionally, results from HRTEM and XRD studies show that the CdSe nanoparticles were amorphous at early reaction stages and became better crystallized after longer reaction times, while the particle size remained the same during the crystallization process. These observations demonstrate the important role of the surface on the optical properties of small CdSe quantum dots and facilitated the spectroscopic monitoring of the crystallization process in quantum dots.

Journal Article↗
PubMed2005

Doped semiconductor nanomaterials.

The development and properties of doped nanomaterials including doped titanium dioxide, doped silicon, and doped cadmium telluride are reviewed, as well as their ultrafast dynamics. Doping nanomaterials provides a flexible way to tune to the properties of the materials while maintaining their high surface areas. The electronic, optical, photochemical, photoelectrochemical, photocatalytic and photoexcited relaxation properties can be tuned towards the desired direction by doping different elements. The materials can be engineered towards specific applications through careful selection of the dopants.

Crystallization↗
PubMed2004

The possible role of hydrogen sulfide as a smooth muscle cell proliferation inhibitor in rat cultured cells.

Hydrogen sulfide (H(2)S) was recently suggested to be a possible endogenous gasotransmitter in physiological concentration. For the purpose of understanding its possible role in the regulation of the cardiovascular system, we explored the potential effect of H(2)S on the proliferation of cultured aortic vascular smooth muscle cells (VSMCs) of rats and mitrogen-activated protein kinase (MAPK) as a signaling transduction pathway. Vascular smooth muscle cells were cultured in vitro and the cells were divided into six groups: (1). control group, (2). serum group, (3). endothelin group, (4). NaHS group, (5). serum + NaHS group, and (6). endothelin + NaHS group. VSMC proliferation was measured by [(3)H]thymidine ([(3)H]TdR) incorporation and MAPK activity in the VSMCs was determined by radioactivity assay. The results showed that endothelin-1 increased VSMC [(3)H]TdR incorporation 2.39-fold ( P << 0.01) and MAPK activity 1.62-fold ( P << 0.01), as compared with controls. Hydrogen sulfide at 5 x 10(-5) mol/l, 1 x 10(-4) mol/l, and 5 x 10(-4) mol/l decreased VSMC [(3)H]TdR incorporation by 16.8%, 26.60%, and 37.40%, respectively, and reduced MAPK activity by 7.37% ( P >> 0.05), 23.39%, and 33.57%, respectively ( P << 0.01). The results demonstrated that H(2)S could dose-dependently suppress the proliferation of VSMCs through the MAPK pathway.

Animals↗
PubMed2003

Semiconductor quantum dots for photodynamic therapy.

The applicability of semiconductor QDs in photodynamic therapy (PDT) was evaluated by studying the interaction between CdSe QDs with a known silicon phthalocyanine PDT photosensitizer, Pc4. The study revealed that the QDs could be used to sensitize the PDT agent through a fluorescence resonance energy transfer (FRET) mechanism, or interact directly with molecular oxygen via a triplet energy-transfer process (TET). Both mechanisms result in the generation of reactive singlet oxygen species that can be used for PDT cancer therapy.

Cadmium Compounds↗
PubMed2003

ACE inhibitors and statins acutely improve endothelial dysfunction of human coronary arterioles.

Long-term treatment with angiotensin-converting enzyme (ACE) inhibitors as well as angiotensin II type 1 (AT(1)) receptor antagonists and statins reduces cardiovascular mortality in patients with coronary artery disease as well as chronic heart failure. Little is known about the acute effects of these compounds on vascular reactivity of coronary resistance vessels. Coronary arterioles were obtained from patients undergoing coronary bypass operation (atherosclerosis group) or valve replacement (control group). Responses to endothelium-dependent agonists (histamine, serotonin, and acetylcholine) as well as to the endothelium-independent agonist sodium nitroprusside (SNP) were investigated under baseline conditions and after incubation (15 min) with lisinopril (ACE inhibitor), candesartan (AT(1) receptor antagonist), or fluvastatin. In atherosclerotic vessels, vasorelaxation was significantly reduced to all endothelium-dependent agonists but not, however, to SNP (77 +/- 8, -24 +/- 16, -46 +/- 24, and 98 +/- 8% relaxation for histamine, serotonin, acetylcholine, and SNP, respectively). Lisinopril and fluvastatin but not candesartan significantly improved the responses to the endothelium-dependent agonists (lisinopril: 94 +/- 4, 17 +/- 22, and -20 +/- 13%; fluvastatin: 96 +/- 8, 23 +/- 21, and -25 +/- 18% relaxation for histamine, serotonin, and acetylcholine, respectively). The effect of lisinopril was prevented by pretreatment with a bradykinin antagonist (HOE-130) and dichloroisocoumarine, an inhibitor of kinine-forming enzymes. Pretreatment with a nitric oxide (NO) synthase inhibitor abolished the improvement of endothelial function by lisinopril and fluvastatin. Vascular reactivity in the control group was not influenced by any of the pharmacological interventions. The data demonstrate that in atherosclerosis, endothelium-dependent relaxation of coronary resistance arteries is severely compromised. The impairment can acutely be reversed by ACE inhibitors and statins via increasing the availability of NO.

Acetylcholine↗
PubMed2003

Hydrothermal syntheses and crystal structures of complex-linked three-Dimensional coordination vanadium selenites: M(4,4'-bipy)(H(2)O)V(2)Se(2)O(10) (M = Co, Ni).

Two inorganic-organic hybrid compounds with the formula M(4,4'-bipy)(H(2)O)V(2)Se(2)O(10) (M = Co, Ni) were hydrothermally synthesized and characterized by single-crystal X-ray diffraction. Compounds Co(4,4'-bipy)(H(2)O)V(2)Se(2)O(10) (1) and Ni(4,4'-bipy)(H(2)O)V(2)Se(2)O(10) (2), which are structural analogues, crystallize in the triclinic space group Ponemacr; with crystal data a = 7.9665(3) A, b = 8.1974(3) A, c = 13.8096(4) A, alpha = 85.704(2) degrees, beta = 73.5180(10) degrees, gamma = 75.645(2) degrees, V = 837.76(5) A(3), and Z = 2 and a = 7.9489(19) A, b = 8.128(2) A, c = 13.709 A, alpha = 85.838(6) degrees, beta = 73.736(8) degrees, gamma = 75.594(9) degrees, V = 823.5(4) A(3), and Z = 2, respectively. [M(4,4'-bipy)(H(2)O)V(2)Se(2)O(10)] (M = Co, Ni) have a three-dimensional structure and consist of two subunits, [(VO(2))(SeO(3))](-) infinite chains and [M(4,4'-bipy)(H(2)O)](2+) fragments. The [(VO(2))(SeO(3))](-) chains are composed of [V(2)Se(4)O(14)](4)(-) clusters linked by VO(4)N triangular bipyramids. The 4,4'-bipy molecule as a bifunctional organic ligand is directly linked to Co or Ni and V atoms, affording the three-dimensionality. The compounds were characterized by infrared spectroscopy and differential thermal and thermogravimetric analyses.

Journal Article↗