Zhenyu Yin

Nanoprobes for in vitro diagnostics of cancer and infectious diseases.

The successful and explosive development of nanotechnology is significantly impacting the fields of biology and medicine. Among the spectacular developments of nanobiotechnology, interest has grown in the use of nanomaterials as nanoprobes for bioanalysis and diagnosis. Herein, we review state-of-the-art nanomaterial-based probes and discuss their applications in in vitro diagnostics (IVD) and challenges in bringing these fields together. Major classes of nanoprobes include quantum dots (QDs), plasmonic nanoparticles, magnetic nanoparticles, nanotubes, nanowires, and multifunctional nanomaterials. With the advantages of high volume/surface ratio, surface tailorability, multifunctionality, and intrinsic properties, nanoprobes have tremendous applications in the areas of biomarker discovery, diagnostics of infectious diseases, and cancer detection. The distinguishing features of nanoprobes for in vitro use, such as harmlessness, ultrasensitivity, multiplicity, and point-of-care use, will bring a bright future of nanodiagnosis.

Magnetite nanoparticles as smart carriers to manipulate the cytotoxicity of anticancer drugs: magnetic control and pH-responsive release

We described the smart and targeted magnetic nanocarriers to control the delivery and release of anticancer drug doxorubicin (DOX) in vitro and demonstrated that they can exhibit much higher cytotoxicity to cancer cells than free DOX. The conjugation of targeted magnetite nanoparticles (∼14 nm in diameter) and DOX molecule via acid-labile imine bond endows the nanocarriers with three advanced features: magnetically controllable, specific targeting, and pH-responsive. The cell toxicity assays indicated the pH-sensitive magnetic nanocarriers (IC50 of 0.13 μg mL−1 to HeLa cells) have much higher anticancer activity than free DOX (IC50 of 1.16 μg mL−1 to HeLa cells). Moreover, the magnetically guided delivery of nanocarriers can further improve the drug efficacy (IC50 of ∼0.087 μg mL−1 to HeLa cells). The arginine–glycine–aspartic acid (RGD)-modified magnetic nanocarriers recognized the specific cells effectively (IC50 of 0.93 μg mL−1 to U-87 MG cells) and showed the increased cytotoxicity to cancer cells under external magnetic fields. This intelligent (magnetically guided, molecular targeted, and pH-responsive) drug delivery system has the ability to improve the chemotherapeutic efficacy and reduce the side effects, which has a great potential to become a favorable strategy for delivery of drugs to the desired sites in patients.

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.

Real-Time Monitoring of Arsenic Trioxide Release and Delivery by Activatable T1 Imaging

Delivery of arsenic trioxide (ATO), a clinical anticancer drug, has drawn much attention to improve its pharmacokinetics and bioavailability for efficient cancer therapy. Real-time and in situ monitoring of ATO behaviors in vivo is highly desirable for efficient tumor treatment. Herein, we report an ATO-based multifunctional drug delivery system that efficiently delivers ATO to treat tumors and allows real-time monitoring of ATO release by activatable T1 imaging. We loaded water-insoluble manganese arsenite complexes, the ATO prodrug, into hollow silica nanoparticles to form a pH-sensitive multifunctional drug delivery system. Acidic stimuli triggered the simultaneous release of manganese ions and ATO, which dramatically increased the T1 signal (bright signal) and enabled real-time visualization and monitoring of ATO release and delivery. Moreover, this smart multifunctional drug delivery system significantly improved ATO efficacy and strongly inhibited the growth of solid tumors without adverse side effects. This strategy has great potential for real-time monitoring of theranostic drug delivery in cancer diagnosis and therapy.

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.

Ubiquitination in Rho signaling.

The Rho family small GTPases of the Ras superfamily play key roles in regulating diverse signaling pathways that control a myriad of fundamental cellular processes such as cytoskeletal dynamics, cell cycle progression, gene expression, cell polarity, migration and cell transformation. The Rho GTPases cycle between an active GTP-bound and an inactive GDP-bound form, which is controlled by many regulators including GEFs, GAPs and GDIs. Recent studies have revealed a new layer of regulation for Rho GTPases, indicating that several members of the Rho family of small GTPases including RhoA, Rac1, and RhoBTB, as well as the Ras family member Rap1B, are also regulated by the ubiquitin-proteasome pathway, which plays important roles in controlling cell polarity, migration, cell transformation and actin dynamics. Importantly, regulators for Rho GTP-GDP cycling such as RhoGDI and Rho-GEF ECT2 were also found to be modulated by the ubiquitin pathway. In this review, we focus on how ubiquitin signaling guides the fate and function of Rho GTPases and their regulators, especially how the E3 ubiquitin ligase Smurf1 regulates cell polarity and motility through targeting RhoA for ubiquitination and degradation.

Immunosuppressive function of bone marrow mesenchymal stem cells on acute rejection of liver allografts in rats.

Bone marrow mesenchymal stem cells (MSCs) demonstrate functions of immunologic regulation. However, little is known about the role of interferon-gamma (IFN-gamma) on MSCs and whether MSCs alone can prevent allograft rejection. We purified MSCs, which were or were not treated with IFN-gamma, to act as regulatory cells in mixed lymphocyte reactions. We measured their expression of PDL-1, MHC-I, MHC-II, CD40, CD54, and CD86. The MSCs stained with carboxyfluorescein diacetate-succinimidyl ester were used to detect homing in vivo. The MSCs were injected into an orthotopic liver transplantation model. The result suggested that IFN-gamma enhances expression of PDL-1, MHC-I, MHC-II, and CD54 and boosts immunosuppressive ability in vivo. The MSCs demonstrated homing to the liver, alleviating acute immunologic rejection of an hepatic graft in rats. We conclude that IFN-gamma may enhance the immunosuppressive function of MSCs to protect liver allografts in rats from acute immunologic rejection.

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.

HOX Antisense lincRNA HOXA-AS2 Promotes Tumorigenesis of Hepatocellular Carcinoma

Background: Recent studies reveal that long non-coding RNAs (LncRNAs) play critical roles in the proliferation and migration of human cancer. Previous report has shown that LncRNA HOXA-AS2 was involved in carcinoma processes. However, the expression and biological function of HOXA-AS2 in hepatocellular carcinoma (HCC) are poorly understood. Methods: Quantitative real-time PCR (qRT-PCR) was performed to detect the expression of HOXA-AS2 in HCC tissues and cell lines. The relation between lncRNA HOXA-AS2 expression and clinicopathological characteristics was assessed by chi-square test. The prognosis was analyzed using Kaplan-Meier method, and compared differences between the two groups by log-rank test. The biological function of HOXA-AS2 on HCC cells were determined both in vitro and in vivo. Results: In the present study, we found that HOXA-AS2 expression was increased in HCC tissues and adjacent normal tissues and high HOXA-AS2 expression was associated with bigger tumor size, advanced tumor stage, and shorter survival time. Knockdown of HOXA-AS2 significantly inhibited HCC cell proliferation and invasion and resulted in an increase of apoptosis. Furthermore, inhibition of HOXA-AS2 in HCC cells significantly repressed tumorigenicity in nude mice. Conclusion: Our results indicated that the inhibition of HOXA-AS2 in HCC cells significantly inhibited cell proliferation in vitro and in vivo, which might provide a potential possibility for targeted therapy of HCC.