In Vitro Targeted Magnetic Delivery and Tracking of Superparamagnetic Iron Oxide Particles Labeled Stem Cells for Articular Cartilage Defect Repair

To assess a novel cell manipulation technique of tissue engineering with respect to its ability to augment superparamagnetic iron oxide particles （SPIO） labeled mesenchymal stem cells （MSCs） density at a localized cartilage defect site in an in vitro phantom by applying magnetic force. Meanwhile, non-invasive imaging techniques were use to track SPIO-labeled MSCs by magnetic resonance imaging （MRI）. Human bone marrow MSCs were cultured and labeled with SPIO. Fresh degenerated human osteochondral fragments were obtained during total knee arthroplasty and a cartilage defect was created at the center. Then, the osteochondral fragments were attached to the sidewalls of culture flasks filled with phosphate-buffered saline （PBS） to mimic the human joint cavity. The SPIO-labeled MSCs were injected into the culture flasks in the presence of a 0.57 Tesla （T） magnetic force. Before and 90 min after cell targeting, the specimens underwent T2-weighted turbo spin-echo （SET2WI） sequence of 3.0 T MRI. MRI results were compared with histological findings. Macroscopic observation showed that SPIO-labeled MSCs were steered to the target region of cartilage defect. MRI revealed significant changes in signal intensity （P0.01）. HE staining exibited that a great number of MSCs formed a three-dimensional （3D） cell ＂sheet＂ structure at the chondral defect site. It was concluded that 0.57 T magnetic force permits spatial delivery of magnetically labeled MSCs to the target region in vitro. High-field MRI can serve as an very sensitive non-invasive technique for the visualization of SPIO-labeled MSCs.

Therapies targeting cancer stem cells: Current trends and future challenges

Traditional therapies against cancer, chemo- and radiotherapy, have multiple limitations that lead to treatment failure and cancer recurrence. These limitations are related to systemic and local toxicity, while treatment failure and cancer relapse are due to drug resistance and self-renewal, properties of a small population of tumor cells called cancer stem cells(CSCs). These cells are involved in cancer initiation, maintenance, metastasis and recurrence. Therefore, in order to develop efficient treatments that can induce a longlasting clinical response preventing tumor relapse it is important to develop drugs that can specifically target and eliminate CSCs. Recent identification of surface markers and understanding of molecular feature associated with CSC phenotype helped with the design of effective treatments. In this review we discuss targeting surface biomarkers, signaling pathways that regulate CSCs self-renewal and differentiation, drug-efflux pumps involved in apoptosis resistance, microenvironmental signals that sustain CSCs growth, manipulation of mi RNA expression, and induction of CSCs apoptosis and differentiation, with specific aim to hamper CSCs regeneration and cancer relapse. Some of these agents are under evaluation in preclinical and clinical studies, most of them for using in combination with traditional therapies. The combined therapy using conventional anticancer drugs with CSCs-targeting agents, may offer a promising strategy for management and eradication of different types of cancers.

A novel gene delivery system targeting cells expressing VEGF receptors

Two ligand oligopeptides GV1 and GV2 were designed according to the putative binding region of VEGF to its receptors. GV1, GV2 and endosome releasing oligopeptide HA20 were conjugated with poly-L-lysine or protamine and the resulting conjugates could interact with DNA in a noncovalent bond to form a complex. Using pSV2-β-galactosidase as a reporter gene, it has been demonstrated that exogenous gene was transferred into bovine aortic arch-derived endothelial cells (ABAE) andhuman malignant melanoma cell lines (A375) in vitro. In vivo experiments, exogenous gene was transferred into tumor vascular endothelial cells and tumor cells of subcutaneously transplanted human colon cancer LOVO, human malignant melanoma A375 and human hepatoma graft in nude mice. This system could also target gene to intrahepatically transplanted human hepatoma injected via portal vein in nude mice. These results are correlated with theGene delivery system targeting VEGF receptors relevant receptors (flt-1, flk-1/KDR) expression on the targeted cells and tissues.

Donor-Derived CD19-Targeted T Cell Infusion Eliminates B Cell Acute Lymphoblastic Leukemia Minimal Residual Disease with No Response to Donor Lymphocytes after Allogeneic Hematopoietic Stem Cell Transplantation

Leukemia relapse is still the leading cause of treatment failure after allogeneic hematopoietic stem cell transplantation (allo-HSCT) for B cell acute lymphoblastic leukemia (B-ALL). Relapsed patients with BALL after allo-HSCT have a very short median survival. Minimal residual disease (MRD) is predictive of forthcoming hematological relapse after hematopoietic stem cell transplantation (HSCT);furthermore, eliminating MRD effectively prevents relapse. Donor lymphoblastic infusion (DLI) is the main established approach to treat B-ALL with MRD after allo-HSCT. However, about one-third of patients with MRD are non-responsive to DLI and their prognosis worsens. Although donor-derived cluster of differentiation (CD)19-directed chimeric antigen receptor-modified (CAR) T cells (CART19s) can potentially cure leukemia, the efficiency and safety of infusions with these cells have not yet been investigated in patients with MRD after HSCT. Between September 2014 and February 2018, six patients each received one or more infusions of CART19s from HSCT donors. Five (83.33%) achieved MRD-negative remission, and one case was not responsive to the administration of CAR T cells. Three of the six patients are currently alive without leukemia. No patient developed acute graft-versus-host disease (aGVHD), and no patient died of cytokine release syndrome. Donor-derived CAR T cell infusions seem to be an effective and safe intervention for patients with MRD in B-ALL after allo-HSCT and for those who were not responsive to DLI.

Mechanisms of hepatocellular carcinoma and challenges and opportunities for molecular targeted therapy

The incidence and mortality of hepatocellular carcinoma(HCC) have fallen dramatically in China and elsewhere over the past several decades. Nonetheless, HCC remains a major public health issue as one of the most common malignant tumors worldwide and one of the leading causes of death caused by cancer in China. Hepatocarcinogenesis is a very complex biological process associated with many environmental risk factors and factors in heredity, including abnormal activation of cellular and molecular signaling pathways such as Wnt/β-catenin, hedgehog, MAPK, AKT, and ERK signaling pathways, and the balance between the activation and inactivation of the proto-oncogenes and anti-oncogenes, and the differentiation of liver cancer stem cells. Molecule-targeted therapy, a new approach for the treatment of liver cancer, blocks the growth of cancer cells by interfering with the molecules required for carcinogenesis and tumor growth, making it both specific and selective. However, there is no one drug completely designed for liver cancer, and further development in the research of liver cancer targeted drugs is now almost stagnant. The purpose of this review is to discuss recent advances in our understanding of the molecular mechanisms underlying the development of HCC and in the development of novel strategies for cancer therapeutics.

A new prospect in cancer therapy: targeting cancer stem cells to eradicate cancer

According to the cancer stem cell theory, cancers can be initiated by cancer stem cells. This makes cancer stem cells prime targets for therapeutic intervention. Eradicating cancer stem cells by efficient targeting agents may have the potential to cure cancer. In this review, we summarize recent breakthroughs that have improved our understanding of cancer stem cells, and we discuss the therapeutic strategy of targeting cancer stem cells, a promising future direction for cancer stem cell research.

Oxymatrine liposome attenuates hepatic fibrosis via targeting hepatic stellate cells

AIM:To investigate the potential mechanism of ArgGly-Asp(RGD) peptide-labeled liposome loading oxymatrine(OM) therapy in CCl 4-induced hepatic fibrosis in rats.METHODS:We constructed a rat model of CCl 4 induced hepatic fibrosis and treated the rats with different formulations of OM.To evaluate the antifibrotic effect of OM,we detected levels of alkaline phosphatase,hepatic histopathology(hematoxylin and eosin stain and Masson staining) and fibrosis-related gene expression of matrix metallopeptidase(MMP)-2,tissue inhibitor of metalloproteinase(TIMP)-1 as well as type Ⅰ procollagen via quantitative real-time polymerase chain reaction.To detect cell viability and apoptosis of hepatic stellate cells(HSCs),we performed 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-diphenytetrazoliumromide assay and flow cytometry.To reinforce the combination of oxymatrine with HSCs,we constructed fluorescein-isothiocyanate-conjugated Arg-Gly-Asp peptide-labeled liposomes loading OM,and its targeting of HSCs was examined by fluorescent microscopy.RESULTS:OM attenuated CCl 4-induced hepatic fibrosis,as defined by reducing serum alkaline phosphatase(344.47 ± 27.52 U/L vs 550.69 ± 43.78 U/L,P < 0.05),attenuating liver injury and improving collagen deposits(2.36% ± 0.09% vs 7.70% ± 0.60%,P < 0.05) and downregulating fibrosis-related gene expression,that is,MMP-2,TIMP-1 and type Ⅰ procollagen(P < 0.05).OM inhibited cell viability and induced apoptosis of HSCs in vitro.RGD promoted OM targeting of HSCs and enhanced the therapeutic effect of OM in terms of serum alkaline phosphatase(272.51 ± 19.55 U/L vs 344.47 ± 27.52 U/L,P < 0.05),liver injury,collagen deposits(0.26% ± 0.09% vs 2.36% ± 0.09%,P < 0.05) and downregulating fibrosis-related gene expression,that is,MMP-2,TIMP-1 and type Ⅰ procollagen(P < 0.05).Moreover,in vitro assay demonstrated that RGD enhanced the effect of OM on HSC viability and apoptosis.CONCLUSION:OM attenuated hepatic fibrosis by inhibiting viability and inducing apoptosis of HSCs.The RGD-labeled formulation enhanced the targeting efficiency for HSCs and the therapeutic effect.

Polylactic Acid Nanoparticles Targeted to Brain Microvascular Endothelial Cells

In this work, blank polylactic acid （PLA） nanoparticles with unstained surface were prepared by the nano-deposition method. On the basis of the preparation, the effect of surface modification on brain microvascular endothelial cells （BMECs） targeting was examined by in vivo experiments and fluorescence microscopy. The results showed that PLA nanoparticles are less toxic than PACA nanoparticles but their BMECs targeting is similar to PACA nanoparticles. The experiments suggest that drugs can he loaded onto the particles and become more stable through adsorption on the surface of PLA nanoparticles with high surface activity. The surface of PLA nanoparticles was obviously modified and the hydrophilicity was increased as well in the presence of non-ionic surfactants on PLA nanoparticles. As a targeting moiety, polysobate 80 （T-80） can facilitate BMECs targeting of PLA nanoparticles.

Ovarian cancer stem cells: Can targeted therapy lead to improved progression-free survival?

Despite significant effort and research funds, epithelial ovarian cancer remains a very deadly disease. There are no effective screening methods that discover early stage disease; the majority of patients are diagnosed with advanced disease. Treatment modalities consist primarily of radical debulking surgery followed by taxane and platinum-based chemotherapy. Newer therapies including limited targeted agents and intraperitoneal delivery of chemotherapeutic drugs have improved disease-free intervals, but failed to yield longlasting cures in most patients. Chemotherapeutic resistance, particularly in the recurrent setting, plagues the disease. Targeting the pathways and mechanisms behind the development of chemoresistance in ovarian cancer could lead to significant improvement in patient outcomes. In many malignancies, including blood and other solid tumors, there is a subgroup of tumor cells, separate from the bulk population, called cancer stem cells(CSCs). These CSCs are thought to be the cause of metastasis, recurrence and resistance. However, todate, ovarian CSCs have been difficult to identify, isolate, and target. It is felt by many investigators that finding a putative ovarian CSC and a chemotherapeutic agent to target it could be the key to a cure for this deadly disease. This review will focus on recent advances in this arena and discuss some of the controversies surrounding the concept.

Histone modifications:Targeting head and neck cancer stem cells

Head and neck squamous cell carcinoma(HNSCC) is the sixth most common cancer worldwide, and is responsible for a quarter of a million deaths annually. The survival rate for HNSCC patients is poor, showing only minor improvement in the last three decades. Despite new surgical techniques and chemotherapy protocols, tumor resistance to chemotherapy remains a significant challenge for HNSCC patients. Numerous mechanisms underlie chemoresistance, including genetic and epigenetic alterations in cancer cells that may be acquired during treatment and activation of mitogenic signaling pathways, such as nuclear factor kappa-light-chain-enhancer-of activated B cell, that cause reduced apoptosis. In addition to dysfunctional molecular signaling, emerging evidence reveals involvement of cancer stem cells(CSCs) in tumor development and in tumor resistance to chemotherapy and radiotherapy. These observations have sparked interest in understanding the mechanisms involved in the control of CSC function and fate. Post-translational modifications of histones dynamically influence gene expression independent of alterations to the DNA sequence. Recent findings from our group have shown that pharmacological induction of posttranslational modifications of tumor histones dynamically modulates CSC plasticity. These findings suggest that a better understanding of the biology of CSCs in response to epigenetic switches and pharmacological inhibitors of histone function may directly translate to the development of a mechanism-based strategy to disrupt CSCs. In this review, we present and discuss current knowledge on epigenetic modifications of HNSCC and CSC response to DNA methylation and histone modifications. In addition, we discuss chromatin modifications and their role in tumor resistance to therapy.

Relevance and therapeutic potential of Cyp A targeting to block apoptosis inducing factor-mediated neuronal cell death

Programmed cell death （PCD） signaling pathways are import- ant contributors to acute neurological insults such as hypox- ic-ischemic brain damage, traumatic brain injury, stroke etc. The pathogenesis of all these diseases is closely linked with ab- erration of apoptotic cell death pathways. Mitochondria play a crucial role during PCD, acting as both sensors of death signals, and as initiators of biochemical path- ways, which cause cell death （Bras et al., 2005）. Cytochrome c was the firstly identified apoptogenic factor released from mitochondria into the cytosol, where it induces apoptosome formation through the activation of caspases. Other proteins, such as apoptosis inducing factor （AIF）, have been subsequently identified as mitochondrial released factors. AIF contributes to apoptotic nuclear DNA damage （Bras et al., 2005）. in a caspase-independent way

Is there a role for systemic targeted therapy after surgical treatment for metastases of renal cell carcinoma?

Metastatic renal cell carcinoma(m RCC) is a challenging disease. Despite the new targeted therapies, complete remissions occur only in 1%-3% of the cases, and the most effective first-line treatment drugs have reached a ceiling in overall survival(ranging from 9 to 49 mo). Metastasectomy remains to be the only curative option in most patients with m RCC. Prognostic nomograms have been recently published, so we have tools to classify patients in risk groups, allowing us to detect the cases with the higher risk of recurrence after metastasectomy. Although sparse, there is some evidence of effectiveness of neoadjuvant targeted therapy before metastasectomy; but with an increase in surgical complications due to the effects of these new drugs in tissue healing. We have aimed to answer the question: Is there a role for systemic targeted therapy after surgical treatment for metastases of renal cell carcinoma? We have made a search in Pubmed database. As far as we know, evidence is low and it's based in case reports and small series of patients treated with adjuvant drugs after neoadjuvant therapy plus metastasectomy in cases of partial response to initial systemic treatment. Despite the limitations and high risk of bias, promising results and cases with longterm survival with this approach have been described. Two ongoing clinical trials may answer the question that concerns us.

Role of the tissue microenvironment as a therapeutic target in hepatocellular carcinoma

Hepatocellular carcinoma is difficult to treat,primarilybecause the underlying molecular mechanisms drivingclinical outcome are still poorly understood.Growingevidence suggests that the tissue microenvironmenthas a role in the biological behavior of the tumor.Themain clinical issue is to identify the best target fortherapeutic approaches.Here,we discuss the hypothesis that the entire tissue microenvironment might beconsidered as a biological target.However,the tissuemicroenvironment consists of several cellular and biochemical components,each of which displays a distinctbiological activity.We discuss the major components ofthis environment and consider how they may interactto promote tumor/host crosstalk.

Targeting head and neck tumoral stem cells： From biologicalaspects to therapeutic perspectives

Head and neck squamous cell cancer(HNSCC) is the sixth most common cancer in the world. Effective therapeutic modalities such as surgery, radiation, chemotherapy and combinations of each are used in the management of the disease. In most cases, treatment fails to obtain total cancer cure. In recent years, it appears that one of the key determinants of treatment failure may be the presence of cancer stem cells(CSCs) that escape currently available therapies. CSCs form a small portion of the total tumor burden but may play a disproportionately important role in determining outcomes. CSCs have stem features such as self-renewal, high migration capacity, drug resistance, high proliferation abilities. A large body of evidence points to the fact that CSCs are particularly resistant to radiotherapy and chemotherapy. In HNSCC, CSCs have been increasingly shown to have an integral role in tumor initiation, disease progression, metastasis and treatment resistance. In the light of such observations, the present review summarizes biological characteristics of CSCs in HNSCC, outlines targeted strategies for the successful eradication of CSCs in HNSCC including targeting the self-renewal controlling pathways, blocking epithelial mesenchymal transition, niche targeting, immunotherapy approaches and highlights the need to better understand CSCs biology for new treatments modalities.

VEGF Pathway-targeted Therapy for Advanced Renal Cell Carcinoma: A Meta-analysis of Randomized Controlled Trials

Immunotherapy which has been in practice for more than 20 years proves effective for the treatment of metastatic renal cell carcinoma （mRCC）. Anti-angiogenesis-targeted therapy has recently been identified as a promising therapeutic strategy for mRCC. This study was aimed to evaluate the effectiveness of vascular endothelial growth factor （VEGF） pathway-targeted therapy for mRCC by comparing its effectiveness with that of immunotherapy. The electronic databases were searched. Randomized controlled trials （RCTs） on comparison of VEGF inhibiting drugs （sorafenib, sunitinib and bevacizumab） with interferon （IFN） or placebo for mRCC treatment were included. Data were pooled to meta-analyze. A total of 7 RCTs with 3451 patients were involved. The results showed that anti-VEGF agents improved progression-free survival （PFS） and offered substantial clinical benefits to patients with mRCC. Among them, sunitinib had a higher overall response rate （ORR） than IFN （47% versus 12%, P〈0.000001）. Bevacizumab plus IFN produced a superior PFS [risk ratio （RR）： 0.86, 95% confidence interval （CI）： 0.76-0.97; P=0.01] and ORR （RR： 2.19; 95% CI： 1.72-2.78; P〈0.00001） in patients with mRCC over IFN, but it yielded an increase by 31% in the risk of serious toxic effects （RR： 1.31; 95% CI 1.20-1.43; P〈0.00001） as compared with IFN. The overall survival （OS） was extended by sorafenib （17.8 months） and sunitinib （26.4 months） as compared with IFN （13 months）. It was concluded that compared with IFN therapy, VEGF pathway-targeted therapies improved PFS and achieved significant therapeutic benefits in mRCC. However, the risk to benefit ratio of these agents needs to be further evaluated.

Quantitative examination of the inhibitory activation of molecular targeting agents in hepatocellular carcinoma patient-derived cell invasion via a novel in vivo tumor model

Background: The outcomes for patients with advanced hepatocellular carcinoma(HCC) receiving sorafenib are far from satisfactory because of treatment resistance to sorafenib. However, the exact mechanism of resistance to sorafenib remains unclear and it is valuable to establish a novel mouse model to quantitatively analyze the inhibition rates of sorafenib on the invasive growth of HCC cells in the liver.Methods: HCC tissue microblocks derived from patients were cultured and mixed with hydrogel drops. Then, hydrogel drops containing microblocks of HCC tissue were attached onto the surface of the livers of nude mice to form lesions or nodules of HCC. The mice received molecular targeting agents through oral administration. Livers with tumor nodules were harvested for H&E staining(hematoxylin-eosin staining) analysis and H&E staining images were quantitatively analyzed using image J software. The invasive growth of HCC cells into the liver was calculated using the depth of the lesions compared with the total thickness of the liver.Results: Microblocks containing cells derived from HCC patients can form lesions in the liver of nude mice. Oral administration of molecular targeting agents inhibited the invasive growth of HCC cells in the liver of nude mice.Conclusions: The model established in this study involves the invasive growth of HCC cells in the liver of nude mice, and the model allows for the quantitative analysis of the inhibitory effect of molecular targeting agents on the invasion of HCC cells in vivo.

Changing the paradigm：the potential for targeted therapy in laryngeal squamous cell carcinoma

Laryngeal squamous cell carcinoma(LSCC) remains a highly morbid and fatal disease. Historically, it has been a model example for organ preservation and treatment stratification paradigms. Unfortunately, survival for LSCC has stagnated over the past few decades. As the era of next-generation sequencing and personalized treatment for cancer approaches, LSCC may be an ideal disease for consideration of further treatment stratification and personalization. Here, we will discuss the important history of LSCC as a model system for organ preservation, unique and potentially targetable genetic signatures of LSCC, and methods for bringing stratified, personalized treatment strategies to the 21^(st) century.

Targeting leukemia stem cells:The new goal of therapy in adult acute myeloid leukemia

The most popular view of hematopoietic cell lineage organization is that of complex reactive or adaptative systems.Leukemia contains a subpopulation of cells that display characteristics of stem cells.These cells maintain tumor growth.The properties of leukemia stem cells indicate that current conventional chemotherapy, directed against the bulk of the tumor,will not be effective.Leukemia stem cells are quiescent and do not respond to cell cycle-specific cytotoxic agents used to treat leukemia and thus contribute to treatment failure. New strategies are required that specifically target this malignant stem cell population.

Magnetic nanoparticles conjugated with “RPE cell-MCP-1 antibody-VEGF antibody” compounds for the targeted therapy of age-related macular degeneration: a hypothesis

Age-related macular degeneration（AMD） is the leading cause of vision loss in the elderly throughout the world. Treatment of AMD utilizing retinal pigment epithelium（RPE） transplantation represents a promising therapy. However, simplex RPE transplantation can only replace the diseased RPE cells, but has no abilities to stop the development of AMD. It has been indicated that oxidization triggers the development of AMD by inducing the dysfunction and degeneration of RPE cells, which results in the upregulation of local monocyte chemotactic protein-1（MCP-1） expression. MCP-1 induces macrophage recruiment which triggers local inflammation. As a result, the expression of vascular endothelial growth factor（VEGF） is upregulated by MCP-1mediated inflammation and results in the formation of choroidal neovascularization（CNV）. We accordingly propose a targeted therapy of AMD by subretinal transplanting the compound of RPE cell, MCP-1 antibody, and VEGF antibody and using a magnetic system to guide RPE cell compounds conjugated with superparamagnetic iron oxide nanoparticles（SPIONs）. Furthermore, SPION-labelled RPE cells can be tracked and detected in vivo by non-invasive magnetic resonance imaging（MRI）. This novel RPE cell transplantation methodology seems very promising to provide a new therapeutic approach for the treatment of AMD.