Are you Yan Jin?

Claim your profile

Publications (6)34.39 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Several RNA targeted therapeutics including antisense oligonucleotides, small interfering RNAs and microRNAs constitute immunostimulatory CpG motifs as integral part of their design. The limited success with free anti-sense oligonucleotides in hematological malignancies in recent clinical trials has been attributed to the CpG motif mediated TLR induced pro-survival effects and inefficient target modulation in desired cells. In an attempt to diminish their off-target pro-survival and pro-inflammatory effects and specific delivery, as a proof of principle, we developed an antibody-targeted liposomal delivery strategy using a clinically relevant CD20 antibody (Rituximab) conjugated lipopolyplex nanoparticles (RIT-INPs) and Bcl-2 targeted anti-sense G3139 as archetypical antisense therapeutics. The adverse immunostimulatory responses were abrogated by selective B cell targeted delivery and early endosomal compartmentalization of G3139 encapsulated RIT-INPs, resulting in reduced NF-kB activation, robust Bcl-2 down-regulation and enhanced sensitivity to fludarabine induced cytotoxicity. Furthermore, significant in-vivo therapeutic efficacy was noted following RIT-INP-G3139 administration in a disseminated xenograft leukemia model. These results demonstrate that CD20 targeted delivery overcomes the immunostimulatory properties of CpG containing oligonucleotide therapeutics and improves efficient gene silencing and in vivo therapeutic efficacy for B-cell malignancies. The broader implications of similar approaches in overcoming immunostimulatory properties of RNA directed therapeutics in hematological malignancies are discussed.
    Blood 11/2012; · 9.78 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Therapeutic use of oligodeoxynucleotides (ODNs) that hybridize to and downregulate target mRNAs encoding proteins that contribute to malignant transformation has a sound rationale, but has had an overall limited clinical success in cancer due to insufficient intracellular delivery. Here we report a development of formulations capable of promoting targeted delivery and enhanced pharmacologic activity of ODNs in acute myeloid leukemia (AML) cell lines and patient primary cells. In this study, transferrin (Tf) conjugated pH-sensitive lipopolyplex nanoparticles (LPs) were prepared to deliver GTI-2040, an antisense ODN against the R2 subunit of ribonucleotide reductase that has been shown to contribute to chemoresistance in AML. LPs had an average particle size around 110 nm and a moderately positive zeta potential at approximately 10 mV. The ODN encapsulation efficiency of LPs was >90%. These nanoparticles could release ODNs at acidic endosomal pH and facilitate the cytoplasmic delivery of ODNs after endocytosis. In addition, Tf-mediated targeted delivery of GTI-2040 was achieved. R2 downregulation at both mRNA and protein levels was improved by 8-fold in Kasumi-1 cells and 2- to 20-fold in AML patient primary cells treated with GTI-2040-Tf-LPs, compared to free GTI-2040 treatment. Moreover, Tf-LPs were more effective than nontargeted LPs, with 10 to 100% improvement at various concentrations in Kasumi-1 cells and an average of 45% improvement at 3 microM concentration in AML patient primary cells. Treatment with 1 microM GTI-2040-Tf-LPs sensitized AML cells to the chemotherapy agent cytarabine, by decreasing its IC(50) value from 47.69 nM to 9.05 nM. This study suggests that the combination of pH sensitive LP formulation and Tf mediated targeting is a promising strategy for antisense ODN delivery in leukemia therapy.
    Molecular Pharmaceutics 11/2009; 7(1):196-206. · 4.57 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A multi-inlet microfluidic hydrodynamic focusing (MF) system to prepare lipopolyplex (LP) containing Bcl-2 antisense deoxyoligonucleotide (ODN) was developed and evaluated. The lipopolyplex nanoparticles consist of ODN:protamine:lipids (1:0.3:12.5wt/wt ratio) and the lipids included DC-Chol:egg PC:PEG-DSPE (40:58:2mol/mol%). Using K562 human erythroleukemia cells, which contain an abundance of Bcl-2 and overexpression of transferrin receptors (TfR), and G3139 (oblimerson sodium or Genasense(TM)) as a model cell line and drug, respectively, the Bcl-2 down-regulation at the mRNA and protein levels as well as cellular uptake and apoptosis was compared between the conventional bulk mixing (BM) method and the MF method. The lipopolyplex size and surface charge were characterized by dynamic light scattering (DLS) and zeta potential (zeta) measurement, respectively, while the ODN encapsulation efficiency was determined by gel electrophoresis. Cryogenic transmission electron microscopy (Cryo-TEM) was used to determine the morphology of LPs. Our results demonstrated that MF produced LP nanoparticles had similar structures but smaller size and size distribution compared to BM LP nanoparticles. MF LP nanoparticles had higher level of Bcl-2 antisense uptake and showed more efficient down-regulation of Bcl-2 protein level than BM LP nanoparticles.
    Journal of Controlled Release 09/2009; 141(1):62-9. · 7.63 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Antisense oligonucleotide G3139-mediated down-regulation of Bcl-2 is a potential strategy for overcoming chemoresistance in leukemia. However, the limited efficacy shown in recent clinical trials calls attention to the need for further development of novel and more efficient delivery systems. In order to address this issue, transferrin receptor (TfR)-targeted, protamine-containing lipid nanoparticles (Tf-LNs) were synthesized as delivery vehicles for G3139. The LNs were produced by an ethanol dilution method, and lipid-conjugated Tf ligand was then incorporated by a postinsertion method. The resulting Tf-LNs had a mean particle diameter of approximately 90 nm and G3139 loading efficiency of 90.4%. Antisense delivery efficiency of Tf-LNs was evaluated in K562, MV4-11, and Raji leukemia cell lines. The results showed that Tf-LNs were more effective than nontargeted LNs and free G3139 (p < 0.05) in decreasing Bcl-2 expression (by up to 62% at the mRNA level in K562 cells) and in inducing caspase-dependent apoptosis. In addition, Bcl-2 down-regulation and apoptosis induced by Tf-LN G3139 were shown to be blocked by excess free Tf and thus were TfR-dependent. Cell lines with higher TfR expression also showed greater Bcl-2 down-regulation. Furthermore, up-regulation of TfR expression in leukemia cells by iron chelator deferoxamine resulted in a further increase in antisense effect (up to 79% Bcl-2 reduction in K562 at the mRNA level) and in caspase-dependent apoptosis (by approximately 3-fold) by Tf-LN. Tf-LN-mediated delivery combined with TfR up-regulation by deferoxamine appears to be a potentially promising strategy for enhancing the delivery efficiency and therapeutic efficacy of antisense oligonucleotides.
    Molecular Pharmaceutics 02/2009; 6(1):221-30. · 4.57 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: CD20 antibody is a FDA-approved therapeutic antibody that has been used in clinical treatment for leukemia. In this study, we conjugated antiCD20 on nano-lipopolyplexes (NLP) carrying Bcl-2 targeted antisense oligonucleotide (AS-ODN) for enhancing delivery to leukemia cells. In comparison to free ODN, the formulated ODN in antiCD20-NLP showed preferential uptake by B leukemia cells. The uptake of AS ODN correlated well with the CD20 expression levels on the cells. antiCD20-NLP mediated ODN delivery can enhance the intracellular Bcl-2 down-regulation in both B cell lines, such as Raji, and leukemia patient cells. The uptake and intracellular trafficking of ODN loaded antiCD20-NLP were characterized by confocal microscopy and Quantum Dot-FRET technology. We also found that the antiCD20 conjugated to NLPs can induce apoptosis on primary leukemia cells by the CD20 cross-linking mechanism. Our findings provide a new approach to improving the clinical efficacy of AS-ODNs therapy in treatment of B cell malignancies. The same approach can also be applied to therapeutic antibodies mediated small interfering RNA (siRNA) delivery for leukemia and other B cell related malignancies.
    2008 AIChE Annual Meeting; 11/2008
  • [Show abstract] [Hide abstract]
    ABSTRACT: To date, efforts to study CD52-targeted therapies, such as alemtuzumab, have been limited due to the lack of stable CD52 expressing transformed B-cell lines and animal models. We describe generation and utilization of cell lines that stably express CD52 both in vitro and in vivo. By limiting dilution, we have established several clones of Raji-Burkitt's lymphoma cell line that express surface CD52. Immunophenotype and cytogenetic characterization of these clones was done. In vivo usefulness of the CD52(high) cell line to evaluate the therapeutic efficacy of CD52-directed antibody was investigated using a SCID mouse xenograft model. Stable expression of CD52 was confirmed in cells cultured in vitro up to 52 weeks of continuous growth. The functional integrity of the expressed CD52 molecule was shown using alemtuzumab, which induced cytotoxic effects in vitro in the CD52(high) but not the CD52(low) clone. Compared with control antibody, alemtuzumab treatment in CD52(high) inoculated mice resulted in significantly increased median survival. Comparable levels of CD52-targeted direct cytotoxicity, complement-dependent cytotoxicity, and antibody-dependent cytotoxicity and anti-CD52 immunoliposome-mediated delivery of synthetic oligodeoxyribo nucleotides in CD52(high) clone and primary B-chronic lymphocytic leukemia cells implicated potential in vivo application of this model for evaluation of CD52-targeted antibody and immunoliposomes encapsulating therapeutic agents. These results show the in vitro utility of the cloned Raji cell lines that stably express high levels CD52. The disseminated leukemia-lymphoma mouse model described herein using these stable cell lines can serve as an excellent system for in vivo therapeutic and mechanistic evaluation of existing and novel antibodies directed against CD52 molecule.
    Clinical Cancer Research 02/2008; 14(2):569-78. · 7.84 Impact Factor