Xiangqian Xiao

Degradable hyaluronic acid/protamine sulfate interpolyelectrolyte complexes as miRNA-delivery nanocapsules for triple-negative breast cancer therapy.

Metastatic relapse is a leading cause of cancer-associated death and one of the major obstacles for effective therapy against triple-negative breast cancer. To address this problem, a miRNA-delivering nanocapsule technology based on hyaluronic acid (HA)/protamine sulfate (PS) interpolyelectrolyte complexes (HP-IPECs) is developed for efficient encapsulation and intracellular delivery microRNA-34a (miR-34a), which is a potent endogenous tumor suppressor of breast cancer. The nanocapsules are successfully generated through a self-assembly approach mediated by an electrostatic interaction. In vitro and in vivo experiments illustrate that miR-34a can be efficiently encapsulated into HP-IPECs and delivered into breast cancer cells or breast cancer tissues. Nanocomplex-assisted delivery of miR-34a induces cell apoptosis and suppresses migration, proliferation, and tumor growth of breast cancer cells via targeting CD44 and a Notch-1-signaling pathway. The obtained results suggest that HP-IPECs have a great potential as a biodegradable vector for microRNA-based therapy against triple-negative breast cancer.

Immunization of N terminus of enterovirus 71 VP4 elicits cross-protective antibody responses

BackgroundEnterovirus 71 (EV71) is major cause of hand, foot and mouth disease. Large epidemics of EV71 infection have been recently reported in the Asian-Pacific region. Currently, no vaccine is available to prevent EV71 infection.ResultsThe peptide (VP4N20) consisting of the first 20 amino acids at the N-terminal of VP4 of EV71 genotype C4 were fused to hepatitis B core (HBcAg) protein. Expression of fusion proteins in E. coli resulted in the formation of chimeric virus-like particles (VLPs). Mice immunized with the chimeric VLPs elicited anti-VP4N20 antibody response. In vitro microneutralization experiments showed that anti-chimeric VLPs sera were able to neutralize not only EV71 of genotype C4 but also EV71 of genotype A. Neonatal mice model confirmed the neutralizing ability of anti-chimeric VLPs sera. Eiptope mapping led to the identification of a “core sequence” responsible for antibody recognition within the peptide.ConclusionsImmunization of chimeric VLPs is able to elicit antibodies displaying a broad neutralizing activity against different genotypes of EV71 in vitro. The “core sequence” of EV71-VP4 is highly conserved across EV71 genotypes. The chimeric VLPs have a great potential to be a novel vaccine candidate with a broad cross-protection against different EV71 genotypes.

Targeting long non-coding RNA ASBEL with oligonucleotide antagonist for breast cancer therapy

Long non-coding RNAs (lncRNAs) are defined as a class of RNA transcripts longer than 200 nucleotides encoded by mammalian genomes that lack protein-coding potential. LncRNA ASBEL has been identified as an anti-sense transcript of BTG3 (B cell translocation gene 3) gene, which encodes an anti-proliferation protein. Remarkable down-regulation of BTG3 has been reported in triple-negative breast cancer (TNBC). In the present study, a number of single-stranded modified anti-sense DNA oligonucleotides (antago) were designed, synthesized and screened for specific lncRNA ASBEL knockdown. We showed here that anti-ASBEL antago played a significant tumor suppressive role in TNBC by effective down-regulating lncRNA ASBEL, which in turn led to increased BTG3 expression. The obtained data suggest lncRNA ASBEL as a novel therapeutic target in TNBC.

miR-100 suppresses the proliferation and tumor growth of esophageal squamous cancer cells via targeting CXCR7

MicroRNAs are highly conserved non-coding RNAs that regulate gene expression at the post-transcriptional level, and play pivotal roles in cancer development and progression. miR-100 has been reported to be significantly downregulated in a variety of cancers, including esophageal cancer. However, the role of miR-100 in human esophageal cancer has not been fully elucidated. We demonstrated that overexpression of miR-100 in esophageal cancer cells markedly inhibited cell proliferation, migration and invasion as well as tumor growth. We subsequently showed that CXCR7 is a direct target gene of miR-100. Our results indicated that miR-100 plays a tumor-suppressor role in esophageal cancer and suggest its potential application for esophageal cancer treatment.

Phage display-derived cross-reactive neutralizing antibody against enterovirus 71 and coxsackievirus A16

Enterovirus 71 (EV71) and coxsackievirus A16 (CVA16) are members of the Picornaviridae family and are considered the main causative agents of hand, foot and mouth disease (HFMD). In recent decades large HFMD outbreaks caused by EV71 and CVA16 have become significant public health concerns in the Asia-Pacific region. Vaccines and antiviral drugs are unavailable to prevent EV71 and CVA16 infection. In the current study, a chimeric antibody targeting a highly conserved peptide in the EV71 VP4 protein was isolated by using a phage display technique. The antibody showed cross-neutralizing capability against EV71 and CVA16 in vitro. The results suggest that this phage display-derived antibody will have great potential as a broad neutralizing antibody against EV71 and CVA16 after affinity maturation and humanization.

EV71 virus-like particles produced by co-expression of capsid proteins in yeast cells elicit humoral protective response against EV71 lethal challenge

BackgroundEnterovirus 71 (EV71) is the most common causative pathogens of hand, foot and mouth disease (HFMD) associated with severe neurological complications. There is a great need to develop prophylactic vaccine against EV71 infection.ResultsEV71 virus-like particle (VLP) was produced in yeast expression system by the co-expression of four EV71 structural proteins VP1–VP4. Immunization with the recombinant VLPs elicited potent anti-EV71 antibody responses in adult mice and anti-VLP sera were able to neutralize EV71 virus in vitro. Neonatal mice model demonstrated VLP immunization conferred protection to suckling mice against the lethal viral challenge.ConclusionsCo-expression of four EV71 structural proteins VP1–VP4 in yeast expression systems is an effective method to produce EV71 VLPs. VLP-based vaccine shows great potential to prevent EV71 infection.

C3-Luc Cells Are an Excellent Model for Evaluation of Cellular Immunity following HPV16L1 Vaccination.

C3 and TC-1 are the two model cell lines most commonly used in studies of vaccines and drugs against human papillomavirus (HPV) infection. Because C3 cells contain both the HPV16 E and L genes, but TC-1 cells contain only the HPV16 E genes, C3 cells are usually used as the model cell line in studies targeting the HPV16 L protein. However, expression of the L1 protein is difficult to detect in C3 cells using common methods. In our study, Short tandem repeat analysis (STR) was used to demonstrate that C3 cells are indeed derived from mice, PCR results show that HPV16 L1, E6 and E7 genes were detected in C3 genomic DNA, and RT-PCR results demonstrated that L1 transcription had occurred in C3 cells. However, the expression of C3 protein was not found in the results of western blot and immunohistochemistry (IHC). Growth and proliferation of C3 were inhibited by mice spleen lymphocytes that had been immunized with a vaccine against HPV16L1. The luciferase gene was integrated into C3 cells, and it was confirmed that addition of the exogenous gene had no effect on C3 cells by comparing cell growth and tumor formation with untransformed cells. Cells stably expressing luciferase (C3-luc) were screened and subcutaneously injected into the mice. Tumors became established and were observed using a Spectrum Pre-clinical in Vivo Imaging System. Tumor size of mice in the different groups at various time points was calculated by counting photons. The sensitivity of the animals to the vaccine was quantified by statistical comparison. Ten or 30 days following injection of the C3-luc cells, tumor size differed significantly between the PBS and vaccine groups, indicating that C3 cells were susceptible to vaccination even after tumors were formed in vivo.

One-prime multi-boost strategy immunization with recombinant DNA, adenovirus, and MVA vector vaccines expressing HPV16 L1 induces potent, sustained, and specific immune response in mice.

Human papillomavirus (HPV) is associated with various human diseases, including cancer, and developing vaccines is a cost-efficient strategy to prevent HPV-related disease. The major capsid protein L1, which an increasing number of studies have confirmed is typically expressed early in infection, is a promising antigen for such a vaccine, although the E6 and E7 proteins have been characterized more extensively. Thus, the L1 gene from HPV16 was inserted into a recombinant vector, AdHu5, and MVA viral vectors, and administered by prime-boost immunization. Virus-like particles were used as control antigens. Our results indicate that prime-boost immunization with heterologous vaccines induced robust and sustained cellular and humoral response specific to HPV16 L1. In particular, sera obtained from mice immunized with DNA + DNA + Ad + MVA had excellent antitumor activity in vivo. However, the data also confirm that virus-like particles can only elicit low levels cellular immunity and not be long-lasting, and are therefore unsuitable for treatment of existing HPV infections.

Nanodiamond-based layer-by-layer nanohybrids mediate targeted delivery of miR-34a for triple negative breast cancer therapy

Triple-negative breast cancer (TNBC) is the most lethal subtype of breast cancer and significantly associated with poor prognosis and high risk of recurrence. miR-34a has been identified as a potent tumor suppressor whose expression is dramatically downregulated in TNBC. Currently, rectification of miRNA abnormality serves as a novel tumor therapeutic strategy. miR-34a is thus used as powerful antitumor agent for miRNA-based therapy against TNBC. However, miRNA-based antitumor therapy is challenged by effective targeted delivery of miRNA. In the present study, nanodiamond (ND), protamine (PS) and folic acid (FA) were used to construct ND-based layer-by-layer nanohybrids through a self-assembly approach for targeted miR-34a delivery in TNBC cells and xenograft TNBC tumors. We found that the targeted delivery of miR-34a remarkably suppressed cell proliferation, migration and induced the apoptosis of TNBC cells in vitro and inhibited tumor growth in vivo via down-regulating Fra-1 expression. The data suggest a great potential of ND-based nanohybrids for targeted intratumoral delivery of miR-34a for TNBC therapy.