Doxorubicin-conjugated siRNA lipid nanoparticles for combination cancer therapy

Evasion of apoptosis is a hallmark of cancer, attributed in part to overexpression of the anti-apoptotic protein B-cell lymphoma 2 (Bcl-2). In a variety of cancer types, including lymphoma, Bcl-2 is overexpressed. Therapeutic targeting of Bcl-2 has demonstrated efficacy in the clinic and is the subject of extensive clinical testing in combination with chemotherapy. Therefore, the development of co-delivery systems for Bcl-2 targeting agents, such as small interfering RNA (siRNA), and chemotherapeutics, such as doxorubicin (DOX), holds promise for enabling combination cancer therapies. Lipid nanoparticles (LNPs) are a clinically advanced nucleic acid delivery system with a compact structure suitable for siRNA encapsulation and delivery. Inspired by ongoing clinical trials of albumin-hitchhiking doxorubicin prodrugs, here we developed a DOX-siRNA co-delivery strategy via conjugation of doxorubicin to the surface of siRNA-loaded LNPs. Our optimized LNPs enabled potent knockdown of Bcl-2 and efficient delivery of DOX into the nucleus of Burkitts' lymphoma (Raji) cells, leading to effective inhibition of tumor growth in a mouse model of lymphoma. Based on these results, our LNPs may provide a platform for the co-delivery of various nucleic acids and DOX for the development of new combination cancer therapies.

Concurrent silencing of TBCE and drug delivery to overcome platinum-based resistance in liver cancer

Platinum-based chemotherapy resistance is a key factor of poor prognosis and recurrence in hepatocellular carcinoma (HCC). Herein, RNAseq analysis revealed that elevated tubulin folding cofactor E (TBCE) expression is associated with platinum-based chemotherapy resistance. High expression of TBCE contributes to worse prognoses and earlier recurrence among liver cancer patients. Mechanistically, TBCE silencing significantly affects cytoskeleton rearrangement, which in turn increases cisplatin-induced cycle arrest and apoptosis. To develop these findings into potential therapeutic drugs, endosomal pH-responsive nanoparticles (NPs) were developed to simultaneously encapsulate TBCE siRNA and cisplatin (DDP) to reverse this phenomena. NPs (siTBCE + DDP) concurrently silenced TBCE expression, increased cell sensitivity to platinum treatment, and subsequently resulted in superior anti-tumor effects both in vitro and in vivo in orthotopic and patient-derived xenograft (PDX) models. Taken together, NP-mediated delivery and the co-treatment of siTBCE + DDP proved to be effective in reversing chemotherapy resistance of DDP in multiple tumor models.

Anti-melanoma effect of intratumoral injection of PD-L1-siRNA-loaded phenylboronic acid-modified chitooligosaccharide nanoparticles: a preliminary study / 国际药学研究杂志

Objective: To prepare phenylboronic acid-modified chitooligosaccharide(PBA-COS)nanoparticles(PBA-COS/ siPD-L1) loaded with PD-L1-siRNA(siPD-L1) and investigate the properties and in vivo anti -melanoma(B16F10) effect of the nanoparticles in mice. Methods: PBA-COS/siPD-L1 nanoparticles were prepared by the complex coacervation method. The particle size and Zeta potential of nanoparticles were investigated by dynamic light scattering. Agarose gel electrophoresis was used to evaluate the binding capacity of PBA-COS carriers to siRNA. The morphology of nanoparticles was observed by transmission electron microscope. In vitro cell uptake efficiency was analyzed by flow cytometry. The mouse subcutaneous B16F10 melanoma model was used to in- vestigate the in vivo effect of intratumoral injection of the nanoparticles on the tumor growth and metastasis. The apoptosis of tumor cells and the lung metastasis of tumors were analyzed and examined by TUNEL staining and HE staining, respectively. Results: The particle size of the PBA-COS/siPD-L1 nanoparticles was(101.9±1.89)nm and the Zeta potential was(25.6±1.52)mV. The nanoparticles were observed to be spherical under the transmission electron microscope. The nanoparticles were efficiently ingestible by B16F10 cells, and the intratumoral injection of the nanoparticles could inhibit tumor growth and lung metastasis of B16F10 melanoma in vivo in mice by inducing the B16F10 cell apoptosis. Conclusion: The intratumoral injection of PBA-OS/siPD-L1 nanoparticles could significantly inhibit tumor growth(the tumor inhibition rate was 42.4%, P<0.01)and lung metastasis of melanoma in mice.

Delivery of BACE1 siRNA mediated by TARBP-BTP fusion protein reduces b-amyloid deposits in a transgenic mouse model of Alzheimer’s disease

Systemic delivery of nucleic acids to the central nervous system (CNS) is a major challenge for the development of RNAinterference-based therapeutics due to lack of stability, target specificity, non-permeability to the blood–brain barrier (BBB),and lack of suitable carriers. Using a designed bi-functional fusion protein TARBP-BTP in a complex with siRNA, weearlier demonstrated knockdown of target genes in the brain of both AbPP-PS1 (Alzheimer’s disease, AD) and wild-typeC57BL/6 mice. In this report, we further substantiate the approach through an extended use in AbPP-PS1 mice, which upontreatment with seven doses of b-secretase AbPP cleaving Enzyme 1 (BACE1) TARBP-BTP:siRNA, led to target-specificeffect in the mouse brain. Concomitant gene silencing of BACE1, and consequent reduction in plaque load in the cerebralcortex and hippocampus ([60%) in mice treated with TARBP-BTP:siRNA complex, led to improvement in spatial learningand memory. The study validates the efficiency of TARBP-BTP fusion protein as an efficient mediator of RNAi, givingconsiderable scope for future intervention in neurodegenerative disorders through the use of short nucleic acids as genespecific inhibitors.

Small interfering RNA delivery to the neurons near the amyloid plaques for improved treatment of Alzheimer׳s disease

Gene therapy represents a promising treatment for the Alzheimer׳s disease (AD). However, gene delivery specific to brain lesions through systemic administration remains big challenge. In our previous work, we have developed an siRNA nanocomplex able to be specifically delivered to the amyloid plaques through surface modification with both CGN peptide for the blood-brain barrier (BBB) penetration and QSH peptide for -amyloid binding. But, whether the as-designed nanocomplex could indeed improve the gene accumulation in the impaired neuron cells and ameliorate AD-associated symptoms remains further study. Herein, we prepared the nanocomplexes with an siRNA against -site amyloid precursor protein-cleaving enzyme 1 (BACE1), the rate-limiting enzyme of A production, as the therapeutic siRNA of AD. The nanocomplexes exhibited high distribution in the A deposits-enriched hippocampus, especially in the neurons near the amyloid plaques after intravenous administration. In APP/PS1 transgenic mice, the nanocomplexes down-regulated BACE1 in both mRNA and protein levels, as well as A and amyloid plaques to the level of wild-type mice. Moreover, the nanocomplexes significantly increased the level of synaptophysin and rescued memory loss of the AD transgenic mice without hematological or histological toxicity. Taken together, this work presented direct evidences that the design of precise gene delivery to the AD lesions markedly improves the therapeutic outcome.

Advances in non-viral vector research of siRNA / 中国药理学通报

siRNA drug research and development is becoming one of the main objectives in the future. However, due to the in-stability of siRNA and the complex environment in vivo, the safe and effective delivery of siRNA is limited in vivo. Thus, special vectors are used to assist siRNA to express biological effects. This paper reviews the advances in non-viral vector for delivery of siRNA in vivo.