Wenxiu Zhao

Engineered Iron-Oxide-Based Nanoparticles as Enhanced T1 Contrast Agents for Efficient Tumor Imaging

We report the design and synthesis of small-sized zwitterion-coated gadolinium-embedded iron oxide (GdIO) nanoparticles, which exhibit a strong T1 contrast effect for tumor imaging through enhanced permeation and retention effect and the ability to clear out of the body in living subjects. The combination of spin-canting effects and the collection of gadolinium species within small-sized GdIO nanoparticles led to a significantly enhanced T1 contrast effect. For example, GdIO nanoparticles with a diameter of ∼4.8 nm exhibited a high r1 relaxivity of 7.85 mM(-1)·S(-1) and a low r2/r1 ratio of 5.24. After being coated with zwitterionic dopamine sulfonate molecules, the 4.8 nm GdIO nanoparticles showed a steady hydrodynamic diameter (∼5.2 nm) in both PBS buffer and fetal bovine serum solution, indicating a low nonspecific protein absorption. This study provides a valuable strategy for the design of highly sensitive iron-oxide-based T1 contrast agents with relatively long circulation half-lives (∼50 min), efficient tumor passive targeting (SKOV3, human ovarian cancer xenograft tumor as a model), and the possibility of rapid renal clearance after tumor imaging.

Activated hepatic stellate cells promote hepatocellular carcinoma development in immunocompetent mice

Activated hepatic stellate cells (HSCs) play a central role in the hepatic fibrosis and cirrhosis. Recently, HSCs were reported to have strong immune modulatory activities. However, the role of HSCs in hepatocellular carcinoma (HCC) remains unclear. In this study, we showed that HSCs could promote HCC growth both in vitro and in vivo. We examined the HSC‐mediated inhibition of T‐cell proliferation and the ability of conditioned medium from activated HSCs to promote the growth of murine HCC cell lines in vitro. We also assessed the immune suppression by HSCs during the development of HCC in immunocompetent mice. Cotransplantation of HSCs promoted HCC growth and progression by enhancing tumor angiogenesis and tumor cell proliferation and by creating an immunosuppressed microenvironment. Cotransplanted HSCs inhibited the lymphocyte infiltration in tumors and the spleens of mice bearing tumors, induced apoptosis of infiltrating mononuclear cells, and enhanced the expression of B7H1 and CD4+CD25+ Treg cells. The immune modulation by HSCs seemed to be systemic. In conclusion, our data provide new information to support an integral role for HSCs in promoting HCC progression in part via their immune regulatory activities, and suggest that HSCs may serve as a therapeutic target in HCC.

Hepatic stellate cells promote tumor progression by enhancement of immunosuppressive cells in an orthotopic liver tumor mouse model

The immunosuppressive properties of hepatic stellate cells (HSCs) contribute to the occurrence and development of hepatocellular carcinoma (HCC). The accumulation of cells with immune suppressive activities, such as myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs) is a key mechanism for tumor immune evasion. However, the impact of HSCs on immune cell populations in tumor-bearing hosts is unclear. In this study, we established an orthotopic liver tumor mouse model for studying the complex tumor–host interactions in HCC. The activated HSCs promoted HCC growth not only induced tumor angiogenesis and lymphangiogenesis, but also significantly increased the suppressive immune cell population of Tregs and MDSCs in the spleen, bone marrow, and tumor tissues of the tumor-bearing mice. Murine HCC cell line H22-activated HSCs also expanded the expression of Tregs and MDSCs in vitro. In conclusion, our study suggests a novel role for HSCs in the HCC microenvironment. HSCs can promote HCC progression by enhancement of the immunosuppressive cell population. Targeting HSCs, which is a new concept in adjuvant immunotherapy, may be introduced in the near future to improve the outcome of patients with HCC.

18β-glycyrrhetinic acid inhibits hepatocellular carcinoma development by reversing hepatic stellate cell-mediated immunosuppression in mice

Hepatic stellate cells (HSCs) have immunosuppressive capabilities and contribute to the occurrence and development of hepatocellular carcinoma (HCC). Thus, activated HSCs may be a suitable target for HCC therapy. Our study used mixed leukocyte reactions (MLR) in vitro to demonstrate that 18β‐glycyrrhetinic acid (GA) could reverse HSC‐mediated immunosuppression by reducing T‐cell apoptosis and regulatory T (Treg) cells expression, thereby enhancing the ability of T cells to attack tumor cells and attenuating HCC cell invasiveness. Moreover, we established a HCC orthotopic implantation model in immunocompetent C57BL/6 mice, which suggested that GA played a protective role in HCC development by reducing immunosuppression mediated by HSCs in the tumor microenvironment.

Decreased expression of ARID1A associates with poor prognosis and promotes metastases of hepatocellular carcinoma

BackgroundHepatocellular carcinoma (HCC) is a common malignancy worldwide, which is especially prevalent in Asia. Elucidating the molecular basis of HCC is crucial to develop targeted diagnostic tools and novel therapies. Recent studies have identified AT-rich interactive domain-containing protein 1A (ARID1A) as a broad-spectrum tumor suppressor. We evaluated the clinical implications of decreased ARID1A expression in HCC, and investigated the mechanisms of ARID1A-mediated tumor suppression.MethodsQuantitative PCR, western blotting, immunohistochemical analysis of ARID1A mRNA and protein expression was conducted in 64 paired HCC and adjacent non-tumorous tissues. ARID1A function was evaluated in vitro in MHCC-97H and Huh7 HCC cell lines, and in vivo in a xenografted HCC tumor model.ResultsARID1A mRNA and protein expression were significantly decreased in HCC tissues, and decreased expression was significantly associated with overall metastasis, including local lymph node and distant metastasis, and poor prognosis. ARID1A knockdown promoted HCC cell migration and invasion in vitro, whereas overexpression of ARID1A inhibited migration and invasion. E-cadherin levels were closely correlated with ARID1A expression, suggesting a role in migration and invasion. In addition, ARID1A and E-cadherin (CDH1) expression were found to be regulated in a coordinated fashion in HCC samples. Furthermore, ARID1A knockdown significantly increased HCC tumor growth and lung metastasis in vivo.ConclusionsARID1A served as an important tumor suppressor. Decreased expression of ARID1A was associated with tumor progression, metastasis, and reduced overall survival in mice and humans. ARID1A could represent a promising candidate therapeutic target for HCC.

The role of hepatic stellate cells in the regulation of T-cell function and the promotion of hepatocellular carcinoma

Hepatic stellate cells (HSCs) have immunosuppressive abilities and may be responsible for the occurrence and development of hepatocellular carcinoma (HCC). However, the mechanisms through which HSCs affect T-cell-mediated immune responses remain unclear. The aim of this study was to elucidate these mechanisms. We examined the effect of HSCs on T-cell proliferation and apoptosis, regulatory T cells (Treg cells) and T-cell-mediated cytotoxicity using mixed leukocyte reactions (MLRs). Furthermore, we examined the cytokines present in the supernatant and the effect of this supernatant on the proliferation and migration of cancer cells. Finally, we examined the effect of HSCs on HCC cells in vivo. We found that activated HSCs induced T-cell hyporesponsiveness, accelerated activated T-cell apoptosis, increased the number of Treg cells and inhibited T-cell-mediated cytotoxicity. HSCs also enhanced the expression of some cytokines and promoted the proliferation and migration of cancer cells. Furthermore, activated HSCs were able to induce HCC proliferation and Treg cells expansion in vivo. Activated HSCs may induce T cell anergy, thereby facilitating the immunologic escape of HCC cells.

Activated hepatic stellate cells promote liver cancer by induction of myeloid-derived suppressor cells through cyclooxygenase-2

Hepatic stellate cells (HSCs) are critical mediators of immunosuppression and the pathogenesis of hepatocellular carcinoma (HCC). Our previous work indicates that HSCs promote HCC progression by enhancing immunosuppressive cell populations including myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs). MDSCs are induced by inflammatory cytokines (e.g., prostaglandins) and are important in immune suppression. However, how HSCs mediate expansion of MDSCs is uncertain. Thus, we studied activated HSCs that could induce MDSCs from bone marrow cells and noted that HSC-induced MDSCs up-regulated immunosuppressive activity via iNOS, Arg-1, and IL-4Rα. After treating cells with a COX-2 inhibitor or an EP4 antagonist, we established that HSC-induced MDSC accumulation was mediated by the COX2-PGE2-EP4 signaling. Furthermore, in vivo animal studies confirmed that inhibition of HSC-derived PGE2 could inhibit HSC-induced MDSC accumulation and HCC growth. Thus, our data show that HSCs are required for MDSC accumulation mediated by the COX2-PGE2-EP4 pathway, and these data are the first to link HSC and MDSC subsets in HCC immune microenvironment and provide a rationale for targeting PGE2 signaling for HCC therapy.

Chloride intracellular channel 1 is overexpression in hepatic tumor and correlates with a poor prognosis

Chloride intracellular channel 1 (CLIC1) is expressed in many human tissues and has been reported to be involved in the regulation of cell cycle, cell proliferation, and differentiation. Its roles in human hepatic tumor, however, remain unclear. The aim of this study was to investigate the clinicopathological significance and expression pattern of CLIC1 in human primary hepatic tumors. We examined the expression pattern of CLIC1 mRNA and protein in hepatic tumors using real‐time quantitative RT‐PCR and Western blot, respectively. CLIC1 protein and mRNA levels were significantly higher in cancerous tissues compared with corresponding normal tissue. In 85 hepatic tumor tissues, CLIC1 was significantly higher in 69 cases (81.2%), as determined by immunohistochemical staining. Increased CLIC1 expression was correlated with tumor size (p = 0.021), distant metastasis (p = 0.025), pathological TNM (pTNM) stage (p = 0.023), and poor survival (25.11 ± 2.27 vs 45.29 ± 4.28 months, p = 0.001). Our data show that increased CLIC1 protein expression is associated with clinicopathological factors and a poor prognosis of hepatic tumors, and suggest that CLIC1 might represent a valuable prognostic marker for human hepatic tumors.

Capsaicin Enhances the Drug Sensitivity of Cholangiocarcinoma through the Inhibition of Chemotherapeutic-Induced Autophagy

Cholangiocarcinoma (CCA), a devastating cancer with a poor prognosis, is resistant to the currently available chemotherapeutic agents. Capsaicin, the major pungent ingredient found in hot red chili peppers of the genus Capsicum, suppresses the growth of several malignant cell lines. Our aims were to investigate the role and mechanism of capsaicin with respect to the sensitivity of CCA cells to chemotherapeutic agents. The effect of capsaicin on CCA tumor sensitivity to 5-fluorouracil (5-FU) was assessed in vitro in CCA cells and in vivo in a xenograft model. The drug sensitivity of QBC939 to 5-FU was significantly enhanced by capsaicin compared with either agent alone. In addition, the combination of capsaicin with 5-FU was synergistic, with a combination index (CI) < 1, and the combined treatment also suppressed tumor growth in the CCA xenograft to a greater extent than 5-FU alone. Further investigation revealed that the autophagy induced by 5-FU was inhibited by capsaicin. Moreover, the decrease in AKT and S6 phosphorylation induced by 5-FU was effectively reversed by capsaicin, indicating that capsaicin inhibits 5-FU-induced autophagy by activating the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway in CCA cells. Taken together, these results demonstrate that capsaicin may be a useful adjunct therapy to improve chemosensitivity in CCA. This effect likely occurs via PI3K/AKT/mTOR pathway activation, suggesting a promising strategy for the development of combination drugs for CCA.

Subsets of myeloid-derived suppressor cells in hepatocellular carcinoma express chemokines and chemokine receptors differentially.

Tumors induce the recruitment and expansion of myeloid-derived suppressor cells (MDSCs), a heterogeneous population of cells that can be further sub-divided into polymorphonuclear Ly6G(+) PMN-MDSCs and monocytic Ly6G(-) Mo-MDSCs. To identify chemokines and chemokine-related genes that are differentially expressed within the tumor microenvironment in these two MDSC subsets, we established an orthotopic hepatocellular carcinoma model in immunocompetent mice. Splenic PMN-MDSCs and Mo-MDSCs were isolated to >95% homogeneity by flow cytometry. Using a real-time PCR array, we investigated the expression of 84 genes encoding chemokines and cytokines, chemokine receptors, and related signaling molecules involved with chemotaxis. Clustering analysis suggested that a core set of chemokine-related genes is expressed in both PMN-MDSC and Mo-MDSC populations, but that the expression profile is broader for Mo-MDSCs. Furthermore, 11 genes are more highly expressed in PMN-MDSCs and 12 genes are more highly expressed in Mo-MDSCs. Among these, PMN-MDSCs express Cxcr1, Cxcr2 and Il1b at 33.03- to 109.76-fold higher levels than in Mo-MDSCs, and Mo-MDSCs express eight genes (Ccr2, Ccr5, Cmklr1, Cx3cr1, Ccr3, Ccl9, Cmtm3 and Cxcl16) at 30.2 to 515.5-fold higher levels than in PMN-MDSCs. These results suggest that the profile of chemokines and chemokine-related genes is more expansive for Mo-MDSCs than for PMN-MDSCs. The differential expression of chemokines and chemokine-associated genes may regulate the presence and activity of PMN-MDSCs and Mo-MDSCs in the tumor microenvironment.