Simultaneous delivery of siRNA and paclitaxel via a "two-in-one" micelleplex promotes synergistic tumor suppression

Enhancing anti-tumor efficiency in hepatocellular carcinoma through the autophagy inhibition by miR-375/sorafenib in lipid-coated calcium carbonate nanoparticles

Sorafenib is a first-line drug for hepatocellular carcinoma (HCC). Autophagy has been shown to facilitate sorafenib resistance. miR-375 has been shown to be an inhibitor of autophagy. In this study, miR-375 and sorafenib were co-loaded into calcium carbonate nanoparticles with lipid coating (miR-375/Sf-LCC NPs). The nanoparticles had high loading efficiency and were ∼50 nm in diameter. Besides, the NPs could increase the stability and residence time of both drugs. Moreover, we demonstrated that autophagy was activated in HCC cells by sorafenib but not by miR-375/Sf-LCC NPs. In vitro, miR-375/Sf-LCC NPs exhibited pH-dependent drug release and potent cytotoxicity. In vivo, miR-375/Sf-LCC NPs increased miR-375 and sorafenib uptake in tumor (2 folds compared with Lipofectamine 2000-miR-375 and 2-5 folds compared with free sorafenib). Furthermore, miR-375/Sf-LCC NPs showed greatly enhanced therapeutic efficacy in an HCC xenograft model. These findings suggest that miR-375/Sf-LCC NPs may be a promising agent for the HCC therapy.

STATEMENT OF SIGNIFICANCE

Hepatocellular carcinoma (HCC) is the most common primary liver tumor and the third leading cause of cancer mortality globally. In this manuscript, miR-375 and sorafenib were co-loaded into calcium carbonate nanoparticles with lipid coating (miR-375/Sf-LCC NPs) to treat HCC. We demonstrated that miR-375/Sf-LCC NPs can deliver sorafenib and miR-375 into HCC cells and tumor tissues, increase drug retention time in tumor, significantly inhibit autophagy and produce enhanced anti-tumor effect.

Smart polymeric nanoparticles with pH-responsive and PEG-detachable properties for co-delivering paclitaxel and survivin siRNA to enhance antitumor outcomes

Background

The co-delivery of chemotherapeutic agents and small interfering RNA (siRNA) within one cargo can enhance the anticancer outcomes through its synergistic therapeutic effects.

Materials and methods

We prepared smart polymeric nanoparticles (NPs) with pH-responsive and poly(ethylene glycol) (PEG)-detachable properties to systemically co-deliver paclitaxel (PTX) and siRNA against survivin gene for lung cancer therapy. The cationic polyethyleneimine-block-polylactic acid (PEI-PLA) was first synthesized and characterized, with good biocompatibility. PTX was encapsulated into the hydrophobic core of the PEI-PLA polymers by dialysis, and then the survivin siRNA was loaded onto the PTX-loaded NPs (PEI-PLA/PTX) through electrostatic interaction between siRNA and PEI block. Finally, the negatively charged poly(ethylene glycol)-block-poly(L-aspartic acid sodium salt) (PEG-PAsp) was coated onto the surface of NPs by electrostatic interaction to form final smart polymeric NPs with mean particle size of 82.4 nm and zeta potential of 4.1 mV. After uptake of NPs by tumor cells, the PEG-PAsp segments became electrically neutral owing to the lower endosome pH and consequently detached from the smart NPs. This process allowed endosomal escape of the NPs through the proton-sponge effect of the exposed PEI moiety.

Results

The resulting NPs achieved drug loading of 6.04 wt% and exhibited good dispersibility within 24 h in 10% fetal bovine serum (FBS). At pH 5.5, the NPs presented better drug release and cellular uptake than at pH 7.4. The NPs with survivin siRNA effectively knocked down the expression of survivin mRNA and protein owing to enhanced cell uptake of NPs. Cell counting kit-8 (CCK-8) assay showed that the NPs presented low systemic toxicity and improved antiproliferation effect of PTX on A549 cells. Moreover, in vivo studies demonstrated that accumulated NPs in the tumor site were capable of inhibiting the tumor growth and extending the survival rate of the mice by silencing the survivin gene and delivering PTX into tumor cells simultaneously.

Conclusion

These results indicate that the prepared nano-vectors could be a promising co-delivery system for novel chemo/gene combination therapy.

Advancements and Challenges in Multidomain Multicargo Delivery Vehicles

Reparative and regenerative processes are well-orchestrated temporal and spatial events that are governed by multiple cells, molecules, signaling pathways, and interactions thereof. Yet again, currently available implantable devices fail largely to recapitulate nature's complexity and sophistication in this regard. Herein, success stories and challenges in the field of layer-by-layer, composite, self-assembly, and core-shell technologies are discussed for the development of multidomain/multicargo delivery vehicles.

Irinotecan/IR-820 coloaded nanocomposite as a cooperative nanoplatform for combinational therapy of tumor

Aim: To enhance synergistic therapeutic effects in breast cancer therapy. Here, we used hollow mesoporous silica nanoparticles as a biocompatible carrier to coload chemotherapy drugs Irinotecan and near-infrared IR-820 dye, which enhanced antitumor efficacy by combining chemotherapy and phototherapy. Methods: The successful synthesis of hollow mesoporous silica nanoparticles/Irinotecan/IR820 (HMII) nanocomplex was confirmed by Fourier  transform infrared spectroscopy and Fluorescence spectra. The photothermal conversion efficiency and antitumor efficiency in murine breast cancer cells (EMT-6) bearing mice were further evaluated. Results: The results demonstrated that HMII enhanced the delivery of Irinotecan and IR-820 into EMT-6 cells. HMII generated a high temperature upon a near-infrared laser irradiation (808 nm), and showed higher therapeutic efficacy in EMT-6-bearing mice compared with either HMII without laser or free drug with a laser. Conclusion: HMII is a desired drug codelivery system to efficiently inhibit the growth of breast cancer.

Sequential delivery of therapeutic agents using a rationally designed disulfide-linked glycolipid-like nanocarrier

Usage of combination therapies to deliver multiple therapeutics to increase treatment efficacy has shown promising results in the clinic. In an effort to maximize the synergistic effect of co-delivery of a drug and siRNA, we have developed a time-dependent sequential drug delivery system (DDS) based on a disulfide-linked chitosan-based nanocarrier (CS-ss-SA) for the co-delivery of paclitaxel (PTX) and Bcl-2 specific siRNA (siBcl-2). This CS-ss-SA nanocarrier is able to transport both drug and siRNA by entrapment of PTX and adsorption of siRNA on the shell by electrostatic attraction. We show that this nanocarrier transports siRNA into tumor cells via its glycolipid-like spatial structure and releases a hydrophobic model drug, Nile Red 8-11 h later. Next, when siRNA and the hydrophobic drug PTX were co-delivered to tumor cells, a synergistic effect was observed in both cell cycle arrest and cell viability. Ultimately, the co-delivery of PTX and siBcl-2 by CS-ss-SA may prove to be more efficacious and may even help overcome drug resistance.

Polydopamine-Functionalized CA-(PCL-ran-PLA) Nanoparticles for Target Delivery of Docetaxel and Chemo-photothermal Therapy of Breast Cancer

Current limitations of cancer therapy include the lack of effective strategy for target delivery of chemotherapeutic drugs, and the difficulty of achieving significant efficacy by single treatment. Herein, we reported a synergistic chemo-photothermal strategy based on aptamer (Apt)-polydopamine (pD) functionalized CA-(PCL-ran-PLA) nanoparticles (NPs) for effective delivery of docetaxel (DTX) and enhanced therapeutic effect. The developed DTX-loaded Apt-pD-CA-(PCL-ran-PLA) NPs achieved promising advantages, such as (i) improved drug loading content (LC) and encapsulation efficiency (EE) initiated by star-shaped copolymer CA-(PCL-ran-PLA); (ii) effective target delivery of drugs to tumor sites by incorporating AS1411 aptamers; (iii) significant therapeutic efficacy caused by synergistic chemo-photothermal treatment. In addition, the pD coating strategy with simple procedures could address the contradiction between targeting modification and maintaining formerly excellent bio-properties. Therefore, with excellent bio-properties and simple preparation procedures, the DTX-loaded Apt-pD-CA-(PCL-ran-PLA) NPs effectively increased the local drug concentration in tumor sites, minimized side effects, and significantly eliminated tumors, indicating the promising application of these NPs for cancer therapy.

Biomimetic Nanovesicles for Enhanced Antitumor Activity of Combinational Photothermal and Chemotherapy

The combination of multiple modalities has shown great potential in cancer treatment with improved therapeutic effects and minimized side effects. Here, we fabricated a type of doxorubicin-encapsulated biomimetic nanovesicle (NV) by a facile method with near-infrared dye insertion in the membrane for combinatorial photothermal and chemotherapy. With innate biomimetic properties, NVs enhanced the uptake by tumor cells while reducing the phagocytosis of macrophages. Upon laser irradiation, NVs can convert the absorbed fluorescent energy into heat for effective tumor killing. Hyperthermia can further induce membrane ablation of NVs to accelerate the release of chemotherapeutic drug for potent cytotoxicity to tumor cells. The NVs improved drug accumulation and showed a more efficient in vivo photothermal effect with a rapid temperature increase in tumors. Moreover, the NV-based combinational photothermal and chemotherapy exhibited significant tumor growth suppression with a high inhibitory rate of 91.6% and negligible systemic toxicity. The results indicate that NVs could be an appealing vehicle for combinational cancer treatment.

Amphiphilic poly(α)glutamate polymeric micelles for systemic administration of siRNA to tumors

RNAi therapeutics carried a great promise to the area of personalized medicine: the ability to target "undruggable" oncogenic pathways. Nevertheless, their efficient tumor targeting via systemic administration had not been resolved yet. Amphiphilic alkylated poly(α)glutamate amine (APA) can serve as a cationic carrier to the negatively-charged oligonucleotides. APA polymers complexed with siRNA to form round-shaped, homogenous and reproducible nano-sized polyplexes bearing ~50 nm size and slightly negative charge. In addition, APA:siRNA polyplexes were shown to be potent gene regulators in vitro. In light of these preferred physico-chemical characteristics, their performance as systemically-administered siRNA nanocarriers was investigated. Intravenously-injected APA:siRNA polyplexes accumulated selectively in tumors and did not accumulate in the lungs, heart, liver or spleen. Nevertheless, the polyplexes failed to induce specific mRNA degradation, hence neither reduction in tumor volume nor prolonged mice survival was seen.

Functional evaluation of doxorubicin decorated polymeric liposomal curcumin: a surface tailored therapeutic platform for combination chemotherapy

The present study deals with the hypothesis and design of new platform for the accommodation of curcumin and doxorubicin in surface engineered liposomes for combination chemotherapy.

ATRP Fabricated and Short Chain Polyethylenimine Grafted Redox Sensitive Polymeric Nanoparticles for Codelivery of Anticancer Drug and siRNA in Cancer Therapy

To overcome the limitations of conventional chemotherapy, nanoparticle-mediated combinatorial delivery of siRNA and drugs represents a new approach to overcome its associated side effects. Designing safe and efficient vehicles for their codelivery has emerged as a potential challenge in the clinical translation of these formulations. Herein, we have demonstrated a novel "two-in-one" polyplex nanosystem developed from redox sensitive, short chain polyethylenimine modified poly[(poly(ethylene)glycol methacrylate]-s-s-polycaprolactone copolymer synthesized by atom-transfer free-radical polymerization (ATRP), which can deliver doxorubicin and polo-like kinase I (plk1) siRNA, simultaneously for an enhanced chemotherapeutic effect. The nanoparticles were found to be stable at physiological buffer with and without fetal bovine serum (FBS). The developed polymeric nanosystem was found to be biocompatible and hemocompatible in vitro and in vivo at repeated dose administrations. The polymer could easily self-assemble into ∼100 nm spherical nanoparticles with enhanced doxorubicin loading (∼18%) and effective siRNA complexation at a polymer to siRNA weight ratio of 15. The doxorubicin loaded nanoparticles exhibited ∼4-fold higher drug release in endosomal pH (pH 5) containing 10 mmol of GSH compared to pH 7.4, depicting their redox-sensitive behavior. The polyplexes were capable of delivering both cargos simultaneously to cancer cells in vitro as observed by their excellent colocalization in the cytoplasm of MDA-MB-231 and HeLa cells using confocal laser microscopy. Moreover, in vitro transfection of the cells with polyplexes exhibited 50-70% knockdown of plk1-mRNA expression in both cell lines. In vivo administration of the drug loaded polyplexes to EAT tumor bearing (EAT, Ehrlich ascites tumor) Swiss albino mice showed a ∼29-fold decrease in percent tumor volume in comparison to the control group. The results highlight the therapeutic potential of the polyplexes as a combined delivery of doxorubicin and plk1-siRNA in cancer therapy.

Targeted iron nanoparticles with platinum-(IV) prodrugs and anti-EZH2 siRNA show great synergy in combating drug resistance in vitro and in vivo

Resistance to platinum agents is challenging in cancer treatment with platinum drugs. Such resistant cells prevent effective platinum accumulation intracellular and alter cellular adaptations to survive from cytotoxicity by regulating corresponding proteins expression. Ideal therapeutics should combine resolution to these pump and non-pump relevant resistance of cancer cells to achieve high efficacy and low side effect. Fe₃O₄ nanocarrier loaded with drugs could enter cells in a more efficient endocytosis manner which circumvents pump-relevant drug resistance. EZH2 protein which was previously found to be over-expressed in drug-resistant cancer cells was reported to be involved in platinum drug resistance and play a vital role in anti-apoptosis pathways. Here, we report Fe₃O₄ nanoparticles loaded with siEZH2 (siRNA), a platinum prodrug in +4 oxidation state (cis, cis, trans-diamminedichlorodisuccinato-platinum-(IV), namely Pt(IV)) and luteinizing hormone-releasing hormone (LHRH) targeting polypeptides. Results show that targeted nanoparticles loading with siEZH2 synergize with Pt(IV) and result in similar cell killing performance to A2780/DDP cells (cisplatin resistant) compared with non-siEZH2 loaded nanoparticles to A2780 cells (cisplatin sensitive). Thus, this Fe₃O₄@PEI-Pt(IV)-PEG-LHRH@siEZH2 nanoparticles reverse the cisplatin resistance from the pump and non-pump relevant aspects, fully taking advantage of nanocarrier system.

A drug-self-gated and tumor microenvironment-responsive mesoporous silica vehicle: "four-in-one" versatile nanomedicine for targeted multidrug-resistant cancer therapy

The design of multifunctional nanocarriers for the co-delivery of anticancer drugs and genetic agents offers an effective and promising strategy to combat multidrug-resistant cancer. Herein, we developed a simple and facile method to fabricate a drug-self-gated and pH-sensitive mesoporous silica vehicle as a "four-in-one" versatile co-delivery system, which possesses targeted chemo and gene therapy capability against multidrug-resistant cancer. P-gp siRNA molecules were loaded into the channels of mesoporous silica nanoparticles. A chemotherapeutic drug (DOX) was employed as a gatekeeper via a pH-sensitive benzoic-imine covalent bond. Folic acid conjugation onto the surface endowed this system with an excellent tumor-targeting effect, which was demonstrated by the cellular and tumor targeting assay. The effective downregulation of P-gp protein by the co-delivered P-gp siRNA was observed by western blotting. Both the in vitro cell viability study and in vivo tumor inhibition assay showed a synergistic effect in suppressing cancer cell proliferation. Therefore, this drug-self-gated nanosystem exhibited great potential for improved multidrug-resistant cancer treatment without any further potential risks of capping agents.

Facile construction of bioreducible crosslinked polypeptide micelles for enhanced cancer combination therapy

In this study, we developed pH and redox-responsive crosslinked polypeptide-based combination micelles for enhanced chemotherapeutic efficacy and minimized side effects. The stability and drug release properties of the polypeptide micelles were efficiency balanced by the corona-crosslinking of the triblock copolymer, poly(ethylene glycol)-b-poly(aspartic acid)-b-poly(tyrosine) (PEG-b-pAsp-b-pTyr) with coordinated redox and pH dual-sensitivity by introducing disulfide crosslinkages. Because of the crosslinking of the middle shell of the triblock polypeptide micelles, their robust structure was maintained in strong destabilization conditions and exhibited excellent stability. GSH concentrations were significantly higher in tumor tissue than in normal tissue, which formed the basis for our design. Drug release was elevated under redox and low acidic conditions. Furthermore, crosslinked micelles showed a superior anticancer effect compared to that of non-crosslinked micelles. Incorporation of docetaxel (DTX) and lonidamine (LND) in crosslinked polypeptide micelles increased the intracellular reactive oxygen species (ROS) level and oxidative stress and caused damage to intracellular components that resulted in greater apoptosis of cancer cells than when DTX or LND was used alone. The combination of DTX and LND in crosslinked micelles exhibited efficacious inhibition of tumor growth with an excellent safety profile compared to that reported for drug cocktail combinations and non-crosslinked micelles. Overall, redox/pH-responsive polypeptide micelles could be an interesting platform for efficient chemotherapy.

STATEMENT OF SIGNIFICANCE

We have synthesized a biodegradable polypeptide block copolymer to construct a facile pH and redox-responsive polymeric micelle asan advanced therapeutic system for cancer therapy. We have designed a corona-crosslinked triblock copolymer (poly (ethylene glycol)-b-poly(aspartic acid)-b-poly(tyrosine) (PEG-b-pAsp-b-pTyr)) micelles co-loaded with docetaxel and lonidamine (cl-M/DL). The corona of triblock polymer was crosslinked to maintain its structural integrity in the physiological environment. The mitochondrial targeting LND is expected to generate ROS, oxidative stress and thereby synergize the chemotherapeutic efficacy of DTX in killing cancer cells. Consistently, cl-M/DL exhibited excellent antitumor efficacy in xenograft tumor model with remarkable tumor regression. Overall, we demonstrated the construction of bioreducible nanosystem for the effective synergistic delivery of DTX/LND in tumor tissues towards cancer treatment.

The potential of multi-compound nanoparticles to bypass drug resistance in cancer

PURPOSE

The therapeutic efficacy of conventional chemotherapy against several solid tumors is generally limited and this is often due to the development of resistance or poor delivery of the drugs to the tumor. Mechanisms of resistance may vary between cancer types. However, with current development of genetic analyses, imaging, and novel delivery systems, we may be able to characterize and bypass resistance, e.g., by inhibition of the right target at the tumor site. Therefore, combined drug treatments, where one drug will revert or obstruct the development of resistance and the other will concurrently kill the cancer cell, are rational solutions. However, drug exposure of one drug will defer greatly from the other due to their physicochemical properties. In this sense, multi-compound nanoparticles are an excellent modality to equalize drug exposure, i.e., one common physicochemical profile. In this review, we will discuss novel approaches that employ nanoparticle technology that addresses specific mechanisms of resistance in cancer.

METHODS

The PubMed literature was consulted and reviewed.

RESULTS

Nanoparticle technology is emerging as a dexterous solution that may address several forms of resistance in cancer. For instance, we discuss advances that address mechanisms of resistance with multi-compound nanoparticles which co-deliver chemotherapeutics with an anti-resistance agent. Promising anti-resistance agents are (1) targeted in vivo gene silencing methods aimed to disrupt key resistance gene expression or (2) protein kinase inhibitors to disrupt key resistance pathways or (3) efflux pumps inhibitors to limit drug cellular efflux.

Multifunctional nanoparticles co-delivering EZH2 siRNA and etoposide for synergistic therapy of orthotopic non-small-cell lung tumor

Malignant proliferation and metastasis in non-small cell lung carcinoma (NSCLC) are great challenges for effective clinical treatment through conventional chemotherapy. The combinational therapy strategy of RNA interfering (RNAi) technology and chemotherapeutic agents have been reported to be promising for effective cancer therapy. In this study, based on multifunctional nanoparticles (NPs), the simultaneous delivery of etoposide (ETP) and anti-Enhancer of Zeste Homologue 2 (EZH2) siRNA for the effective treatment of orthotopic lung tumor was achieved. The NPs exhibited pH/redox dual sensitivity verified by particle size changes, morphological changes, and in vitro release of drugs. Confocal microscopy analysis confirmed that the NPs exhibited endosomal escape property and on-demand intracellular drug release behavior, which can protect siRNA from degradation and facilitate the chemotherapeutic effect respectively. In vitro tumor cell motility study demonstrated that EZH2 siRNA loaded in NPs can decrease the migration and invasion capabilities of tumor cells by downregulating the expression of EZH2 mRNA and protein. In particular, an antiproliferation study revealed that the co-delivery of siRNA and ETP in the multifunctional NPs can induce a synergistic therapeutic effect on NSCLC. In vivo targeting evaluation showed that cRGDyC-PEG modification on NPs exhibited a low distribution in normal organs and an obvious accumulation in orthotopic lung tumor. Furthermore, targeted NPs co-delivering siRNA and ETP showed superior inhibition on tumor growth and metastasis and produced minimal systemic toxicity. These findings indicated that multifunctional NPs can be utilized as a co-delivery system, and that the combination of EZH2 siRNA and ETP can effectively treat NSCLC.

Nanocarriers for TRAIL delivery: driving TRAIL back on track for cancer therapy

Since its initial identification, tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) has been shown to be capable of selectively inducing apoptosis in cancer cells. However, translation of the encouraging preclinical studies of this cytokine into the clinic has been restricted by its extremely short half-life, the presence of resistant cancer cell populations, and its inefficient in vivo delivery. Recently, there has been exceptional progress in developing novel formulations to increase the circulatory half-life of TRAIL and new combinations to treat cancers that are resistant to TRAIL. In particular, TRAIL-based nanotherapies offer the potential to improve the stability of TRAIL and prolong its half-life in plasma, to specifically deliver TRAIL to a particular target site, and to overcome resistance to TRAIL. The aim of this review is to provide an overview of the state-of-the art drug delivery systems that are currently being tested or developed to improve the biological attributes of TRAIL-based therapies.

Elaboration on the Distribution of Hydrophobic Segments in the Chains of Amphiphilic Cationic Polymers for Small Interfering RNA Delivery

Hydrophobization of cationic polymers, as an efficient strategy, had been widely developed in the structure of cationic polymer micelles to improve the delivery efficiency of nucleic acids. However, the distribution of hydrophobic segments in the polymer chains is rarely considered. Here, we have elaborated three types of hydrophobized polyethylene glycol (PEG)-blocked cationic polymers with different distributions of the hydrophobic segments in the polymer chains PEG-PAM-PDP (E-A-D), PEG-PDP-PAM (E-D-A), and PEG-P(AM/DP) (E-(A/D)), which were synthesized by reversible addition-fragmentation chain transfer polymerization of methoxy PEG, cationic monomer aminoethyl methacrylate, and pH-sensitive hydrophobic monomer 2-diisopropylaminoethyl methacrylate, respectively. In aqueous solution, all of the three copolymers, E-A-D, E-D-A, and E-(A/D), were able to spontaneously form nanosized micelles (100-150 nm) (M_E-A-D, M_E-D-A, and M_E-(A/D)) and well-incorporated small interfering RNA (siRNA) into complex micelles (CMs). The effect of distributions of the hydrophobic segments on siRNA delivery had been evaluated in vitro and in vivo. Compared with M_E-D-A and M_E-(A/D), M_E-A-D showed the best siRNA binding capacity to form stable M_E-A-D/siRNA CMs less than 100 nm, mediated the best gene-silencing efficiency and inhibition effect of tumor cell growth in vitro, and showed better liver gene-silencing effect in vivo. In the case of M_E-(A/D) with a random distribution of cationic and hydrophobic segments, a gene-silencing efficiency higher than Lipo2000 but lesser than M_E-A-D and M_E-D-A was obtained. As the mole ratio of positive and negative charges increased, M_E-D-A/siRNA and M_E-A-D/siRNA showed similar performances in size, zeta potential, cell uptake, and gene silencing, but M_E-(A/D)/siRNA showed reversed performances. In addition, M_E-A-D as the best siRNA carrier was evaluated in the tumor tissue in the xenograft murine model and showed good anticancer capacity. Obviously, the distribution of the hydrophobic segments in the amphiphilic cationic polymer chains should be seriously considered in the design of siRNA vectors.

Gold nanoconjugates reinforce the potency of conjugated cisplatin and doxorubicin

Osteosarcoma or osteogenic sarcoma is the most common and prevalent cancerous tumor of bone and occurs especially in children and teens. Recent treatment strategy includes a combination of both chemotherapy and surgeries. Although, the use of single drug-based chemotherapy treatment remains unsatisfactory. Therefore, combinatorial therapy has emerged as a potential strategy for treatment with limited side- effects. Here, we evaluated the combinatorial anticancerous effect of cisplatin (CIS) and doxorubicin (DOX) bioconjugated bromelain encapsulated gold nanoparticles (B-AuNPs conjugated CIS and DOX) in the treatment of osteosarcoma. The synthesized B-AuNPs conjugated CIS and DOX were characterized by various characterization techniques like UV-vis spectroscopy, TEM, DLS and zeta potential to ensure the synthesis, size, shape, size distribution and stability. Drug loading efficiency bioconjugation of CIS and DOX was ensured by UV-vis spectroscopy. Bioconjugation of CIS and DOX was further confirmed using UV-vis spectroscopy, TEM, DLS, Zeta potential and FT-IR analysis. The combinatorial effect of CIS and DOX in B-AuNPs conjugated CIS and DOX showed highly improved potency against MG-63 and Saos-2 cells at a very low concentration where primary osteoblasts didn't show any cytotoxic effect. The apoptotic effect of B-AuNPs conjugated CIS and DOX on osteosarcoma and primary osteoblasts cells were analyzed by increased permeability of the cell membrane, condensed chromatin and deep blue fluorescent condensed nucleus. The results clearly showed that B-AuNPs conjugated CIS and DOX significantly improved the potency of both the chemotherapeutic drugs by delivering them specifically into the nucleus of cancer cells through caveolae-dependent endocytosis. Thus, the greater inhibitory effect of combinatorial drugs (B-AuNPs conjugated CIS and DOX) over single drug based chemotherapy would be of great advantage during osteosarcoma treatment.

Combining Smoothened Agonist and NEL-Like Protein-1 Enhances Bone Healing

BACKGROUND

Nonhealing bone defects represent an immense biomedical burden. Despite recent advances in protein-based bone regeneration, safety concerns over bone morphogenetic protein-2 have prompted the search for alternative factors. Previously, the authors examined the additive/synergistic effects of hedgehog and Nel-like protein-1 (NELL-1) on the osteogenic differentiation of mesenchymal stem cells in vitro. In this study, the authors sought to leverage their previous findings by applying the combination of Smoothened agonist (SAG), hedgehog signal activator, and NELL-1 to an in vivo critical-size bone defect model.

METHODS

A 4-mm parietal bone defect was created in mixed-gender CD-1 mice. Treatment groups included control (n = 6), SAG (n = 7), NELL-1 (n = 7), and SAG plus NELL-1 (n = 7). A custom fabricated poly(lactic-co-glycolic acid) disk with hydroxyapatite coating was used as an osteoinductive scaffold.

RESULTS

Results at 4 and 8 weeks showed increased bone formation by micro-computed tomographic analyses with either stimulus alone (SAG or NELL-1), but significantly greater bone formation with both components combined (SAG plus NELL-1). This included greater bone healing scores and increased bone volume and bone thickness. Histologic analyses confirmed a significant increase in new bone formation with the combination therapy SAG plus NELL-1, accompanied by increased defect vascularization.

CONCLUSIONS

In summary, the authors' results suggest that combining the hedgehog signaling agonist SAG and NELL-1 has potential as a novel therapeutic strategy for the healing of critical-size bone defects. Future directions will include optimization of dosage and delivery strategy for an SAG and NELL-1 combination product.

Multifunctional Molecular Beacon Micelles for Intracellular mRNA Imaging and Synergistic Therapy in Multidrug-Resistant Cancer Cells

Multidrug resistance (MDR) resulting from overexpression of P-glycoprotein (Pgp) transporters increases the drug efflux and thereby limits the chemotherapeutic efficacy. It is desirable to administer both an MDR1 gene silencer and a chemotherapeutic agent in a sequential way to generate a synergistic therapeutic effect in multidrug-resistant cancer cells. Herein, we rationally designed an anti-MDR1 molecular beacon (MB)-based micelle (a-MBM) nanosystem, which is composed of a diacyllipid core densely packed with an MB corona. One of Pgp-transportable agents, doxorubicin (DOX), was encapsulated in the hydrophobic core of the micelle and in the stem sequence of MB. The a-MBM-DOX nanosystem showed an efficient self-delivery, enhanced enzymatic stability, excellent target selectivity, and high drug-loading capacity. With its relatively high enzymatic stability, a-MBM-DOX initially facilitated intracellular MDR1 mRNA imaging to distinguish multidrug-resistant and non-multidrug-resistant cells and subsequently downregulated the MDR1 gene expression owing to an antisense effect. After that, the MB corona was degraded, destroying the micellar nanostructure and releasing DOX, which resulted in a high accumulation of DOX in OVCAR8/ADR cells and a high chemotherapeutic efficacy owing to successful restoration of drug sensitivity. This micelle approach has the potential for both visualizing MDR1 mRNA and overcoming MDR in a sequential and synergistic way.

pH-sensitive polymeric nanoparticles for co-delivery of doxorubicin and curcumin to treat cancer via enhanced pro-apoptotic and anti-angiogenic activities

Co-delivery of multiple drugs with complementary anticancer mechanisms by nano-carriers offers an effective strategy to treat cancer. The combination of drugs with pro-apoptotic and anti-angiogenic activities is potentially effective in treating human hepatocellular carcinoma (HCC). Herein, we developed a co-delivery system for doxorubicin (Dox), a pro-apoptotic drug, and curcumin (Cur), a potent drug for antiangiogenesis, in pH-sensitive nanoparticles (NPs) constituted with amphiphilic poly(β-amino ester) copolymer. Dox & Cur co-loaded NPs ((D+C)/NPs) were prepared with optimized drug ratio, showing low polydispersity, high encapsulation efficiency, and enhanced release in the acidic environment of cancer cells. Furthermore, enhanced cellular internalization of cargoes delivered from (D+C)/NPs were observed in human liver cancer SMMC 7721 cells and human umbilical vein endothelial cells (HUVECs) compared to the use of free drugs. The (D+C)/NPs induced a high rate of apoptosis in SMMC 7721 cells through decreased mitochondrial membrane potential. Additionally, (D+C)/NPs exhibited stronger anti-angiogenic effects including inhibition of HUVEC proliferation, migration, invasion, and tube formation mediated VEGF pathway modulation in vitro and in vivo. Taken together, encapsulation of the pro-apoptotic drug Dox and antiangiogenic agent Cur in pH-sensitive NPs provides a promising strategy to effectively inhibit HCC progression in a synergistic manner.

STATEMENT OF SIGNIFICANCE

The combination of multiple drugs has been demonstrated to be more effective than single treatment. However, the different physicochemical and pharmacokinetic profiles of each drug render optimal delivery challenging. In view of the great delivery advantage of nanocarriers to unify the multiple drugs in vivo, stimulus-responsive nano-carriers are more crucial to increase efficacy and reduce toxicity from off-target exposure. Therefore, herein the pH-sensitive nanoparticles, composed by d-α-tocopheryl polyethylene glycol 1000-block-poly (β-amino ester) (TPGS-PAE) polymers, have been fabricated for doxorubicin (Dox) and curcumin (Cur) co-delivery, which exhibited diverse anticancer approaches, i.e. pro-apoptosis and antiangiogenesis. The precise intracellular target site and effective drug combination concentration result in the enhanced antitumor efficiency and the reduced systematic toxicity of Dox. The co-encapsulation of the pro-apoptotic drug and antiangiogenic agent in pH-sensitive NPs provides a promising strategy to effectively inhibit malignant neoplasm progression in a synergistic manner.

Co-delivery of paclitaxel and anti-survivin siRNA via redox-sensitive oligopeptide liposomes for the synergistic treatment of breast cancer and metastasis

The overexpression of survivin in breast cancer cells is an important factor of paclitaxel (PTX) resistance in breast cancer. To overcome PTX resistance and improve the antitumor effect of PTX, we developed a novel liposome-based nanosystem (PTX/siRNA/SS-L), composed of a redox-sensitive cationic oligopeptide lipid (LHSSG2C₁₄) with a proton sponge effect, natural soybean phosphatidylcholine (SPC), and cholesterol for co-delivery of PTX and anti-survivin siRNA, which could specifically downregulate survivin overexpression. PTX/siRNA/SS-L exhibited high encapsulation efficiency and rapid redox-responsive release of both PTX and siRNA. Moreover, in vitro studies on the 4T1 breast cancer cells revealed that PTX/siRNA/SS-L offered significant advantages over other experimental groups, such as higher cellular uptake, successful endolysosomal escape, reduced survivin expression, the lowest cell viability and wound healing rate, as well as the highest apoptosis rate. In particular, in vivo evaluation of 4T1 tumor-bearing mice showed that PTX/siRNA/SS-L had lower toxicity and induced a synergistic inhibitory effect on tumor growth and pulmonary metastasis. Collectively, the collaboration of anti-survivin siRNA and PTX via redox-sensitive oligopeptide liposomes provides a promising strategy for the treatment of breast cancer and metastasis.

Magnetic alginate microspheres detected by MRI fabricated using microfluidic technique and release behavior of encapsulated dual drugs

Alginate microspheres loaded with superparamagnetic iron oxide nanoparticles (SPIO NPs) have been fabricated by a T-junction microfluidic device combined with an external ionic crosslinking. The obtained microspheres possess excellent visuality under magnetic resonance due to the presence of only 0.6 mg/mL SPIO NPs. The microspheres also show uniform size with narrow distribution and regular spherical shape characterized by optic microscope and environmental scanning electron microscope. Furthermore, dual drugs (5-fluorouracil and doxorubicin hydrochloride) have been loaded within the microspheres. The release behavior of dual drugs from the microspheres show typical sustained release profiles. As a novel embolic agent, such microspheres in blood vessels can be tracked by magnetic resonance scanner. Thus, the integration of embolotherapy, chemotherapy, and postoperative diagnosis can be realized.

NIR responsive liposomal system for rapid release of drugs in cancer therapy

To design a rapid release liposomal system for cancer therapy, a NIR responsive bubble-generating thermosensitive liposome (BTSL) system combined with photothermal agent (Cypate), doxorubicin (DOX), and NH4HCO3 was developed. Cypate/DOX-BTSL exhibited a good aqueous stability, photostability, and photothermal effect. In vitro release suggested that the amounts of DOX released from BTSL were obviously higher than that of (NH4)2SO4 liposomes at 42°C. After NIR irradiation, the hyperthermic temperature induced by Cypate led to the decomposition of NH4HCO3 and the generation of a large number of CO2 bubbles, triggering a rapid release of drugs. Confocal laser scanning microscope and acridine orange staining indicated that Cypate/DOX-BTSL upon irradiation could facilitate to disrupt the lysosomal membranes and realize endolysosomal escape into cytosol, improving the intracellular uptake of DOX clearly. MTT and trypan blue staining implied that the cell damage of Cypate/DOX-BTSL with NIR irradiation was more severe than that in the groups without irradiation. In vivo results indicated that Cypate/DOX-BTSL with irradiation could dramatically increase the accumulation of DOX in tumor, inhibit tumor growth, and reduce systemic side effects of DOX. These data demonstrated that Cypate/DOX-BTSL has the potential to be used as a NIR responsive liposomal system for a rapid release of drugs in thermochemotherapy.

The generation of compartmentalized nanoparticles containing siRNA and cisplatin using a multi-needle electrohydrodynamic strategy

This study outlines a novel manufacturing technique for the generation of compartmentalized trilayered nanoparticles loaded with an anti-cancer agent and siRNA as a platform for the combination treatment of cancers. More specifically, we describe the use of a multi-needle electrohydrodynamic approach to produce nanoparticles with high size specificity and scalable output, while allowing suitable environments for each therapeutic agent. The inner polylactic-glycolic-acid (PLGA) layer was loaded with cisplatin while the middle chitosan layer was loaded with siRNA. The corresponding polymeric solutions were characterized for their viscosity, surface tension and conductivity, while particle size was determined using dynamic light scattering. The internal structure was studied using transmission electron microscopy (TEM) and Structured Illumination Microscopy (SIM). The inclusion of cisplatin was studied using electron dispersive spectroscopy (EDS). We were able to generate nanoparticles of approximate size 130 nm with three distinct layers containing an outer protective PLGA layer, a middle layer of siRNA and an inner layer of cisplatin. These particles have the potential not only for uptake into tumors via the enhanced permeability and retention (EPR) effect but also the sequential release of the siRNA and chemotherapeutic agent, thereby providing a means of overcoming challenges of targeting and tumor drug resistance.

Lipid nanoparticle-based co-delivery of epirubicin and BCL-2 siRNA for enhanced intracellular drug release and reversing multidrug resistance

At present, combined therapy has become an effective strategy for the treatment of cancer. Co-delivery of the chemotherapeutic drugs and siRNA can more effectively inhibit tumor growth by nano drug delivery systems (NDDSs). Here, we prepared and evaluated a multifunctional envelope-type nano device (MEND). This MEND was a kind of composite lipid-nanoparticles possessing both the properties of liposomes and nanoparticles. In this study, an acid-cleavable ketal containing poly (β-amino ester) (KPAE) was used to bind siBCL-2 and the KPAE/siBCL-2 complexes were further coated by epirubicin (EPI) containing lipid to form EPI/siBCL-2 dual loaded lipid-nanoparticles. The results showed that the average size of EPI/siBCL-2-MEND was about 120 nm, and the average zeta potential was about 41 mV. The encapsulation efficiency (EE) of EPI and siBCL-2 was 86.13% and 97.07%, respectively. EPI/siBCL-2 dual loaded lipid-nanoparticles showed enhanced inhibition efficiency than individual EPI-loaded liposomes on HepG₂ cells by MTT assay. Moreover, western blot experiment indicated co-delivery of EPI/siBCL-2 can significantly down-regulate the expression of P-glycoprotein (P-gp), while free EPI and EPI-loaded liposomes up-regulated it. Therefore, the strategy of co-delivering EPI and siBCL-2 simultaneously by lipid-nanoparticles showed promising potential in reversing multidrug resistance of tumor cells.

siRNA Delivery Strategies: A Comprehensive Review of Recent Developments

siRNA is a promising therapeutic solution to address gene overexpression or mutations as a post-transcriptional gene regulation process for several pathological conditions such as viral infections, cancer, genetic disorders, and autoimmune disorders like arthritis. This therapeutic method is currently being actively pursued in cancer therapy because siRNA has been found to suppress the oncogenes and address mutations in tumor suppressor genes and elucidate the key molecules in cellular pathways in cancer. It is also effective in personalized gene therapy for several diseases due to its specificity, adaptability, and broad targeting capability. However, naked siRNA is unstable in the bloodstream and cannot efficiently cross cell membranes besides being immunogenic. Therefore, careful design of the delivery systems is essential to fully utilize the potential of this therapeutic solution. This review presents a comprehensive update on the challenges of siRNA delivery and the current strategies used to develop nanoparticulate delivery systems.

Redox-Activatable ATP-Depleting Micelles with Dual Modulation Characteristics for Multidrug-Resistant Cancer Therapy

A fast adenosine triphosphate (ATP)-depleting micellar system that is activated by intracellular redox for the codelivery of anticancer drug paclitaxel (PTX) and small interference RNA (siRNA) targeting polo-like kinase1 (PLK1) is developed to address the key challenges of multidrug-resistant (MDR) cancer therapy. The ATP-depleting micelle is self-assembled from a redox-responsive amphiphilic polymer (termed as bPEG-SS-P123-PEI (PSPP)) that is composed of biocompatible branched polyethylene glycol (PEG) with 8 arms (bPEG), ATP-depleting Pluronic P123 (P123), and cationic low molecular weight polyethylenimine (PEI) blocks. Upon critical micelle concentration, the PSPP unimer self-assembles into a well-ordered multilayered nanostructure and is able to load PTX and siRNA targeting PLK1. The cleavage of disulfide linkages at intracellular glutathione-rich reduction milieu not only promotes PTX and siRNA release, but also activates the fast ATP-depletion action that is critical in preventing intracellular PTX efflux by multidrug-resistant cancer cells. The combination of ATP depletion and siRNA inhibition by PSPP micelles is found to provide dual modulations for resensitizing multidrug-resistant cancer cells for PTX treatment. As a result, the codelivery of PTX and PLK1 siRNA exerts a stronger combinational effect against tumor growth in MDR tumor models in vivo. The development of fast ATP-depleting nanomicelle represents an original delivery strategy for the distinctive dual modulation of cancer MDR with spatial and temporal control.

Polyphosphoester nanoparticles as biodegradable platform for delivery of multiple drugs and siRNA

Delivery of multiple therapeutics and/or diagnostic agents to diseased tissues is challenging and necessitates the development of multifunctional platforms. Among the various strategies for design of multifunctional nanocarriers, biodegradable polyphosphoester (PPE) polymers have been recently synthesized via a rapid and simple synthetic strategy. In addition, the chemical structure of the polymer could be tuned to form nanoparticles with varying surface chemistries and charges, which have shown exceptional safety and biocompatibility as compared to several commercial agents. The purpose of this study was to exploit a mixture of PPE nanoparticles of cationic and neutral surface charges for multiple delivery of anticancer drugs (ie, sorafenib and paclitaxel) and nucleic acids (ie, siRNA). Cationic PPE polymers could efficiently complex siRNA, and the stability of the nanoparticles could be maintained in physiological solutions and upon freeze-drying and were able to deliver siRNA in vivo when injected intravenously in mice. Commercially available cationic polyethylenimine polymer had LD50 of ca. 61.7 mg/kg in mice, whereas no animal died after injection of the cationic PPE polymer at a dose of >130 mg/kg. Neutral PPE nanoparticles were able to encapsulate two hydrophobic drugs, namely, sorafenib and paclitaxel, which are commonly used for the treatment of hepatocellular carcinoma. Mixing the neutral and cationic PPE nanoparticles did not result in any precipitation, and the size characteristics of both types of nanoparticles were maintained. Hence, PPE polymers might have potential for the delivery of multiple drugs and diagnostic agents to diseased tissues via simple synthesis of the individual polymers and assembly into nanoparticles that can host several drugs while being mixed in the same administration set, which is of importance for industrial and clinical development.

Dual responsive hydrogels based on functionalized mesoporous silica nanoparticles as an injectable platform for tumor therapy and tissue regeneration

A dual responsive hydrogel based on MSNs was fabricated to offer a strategy for sequential tumor therapy and tissue regeneration.

Targeted Co-delivery of PTX and TR3 siRNA by PTP Peptide Modified Dendrimer for the Treatment of Pancreatic Cancer

A new type of tumor-targeted nanovehicle peptide-conjugated PSPG (PSPGP) is successfully synthesized for co-delivery of paclitaxel (PTX) and TR3 small interfering RNA (siRNA). In vitro and in vivo investigations demonstrate that the redox-responsive PSPGP exhibit enhanced endosomal escape and intracellular degradation, which facilitate PTX and TR3 siRNA release, effectively improving the antitumor efficacy.

Nanocarrier-based co-delivery of small molecules and siRNA/miRNA for treatment of cancer

Aberrant gene expression can trigger several vital molecular events that not only result in carcinogenesis but also cause chemoresistance, metastasis and relapse. Gene-based therapies using siRNA/miRNA have been suggested as new treatment method to improve the current regimen. Although these agents can restore the normal molecular cascade thereby resensitizing the cancer cells, delivering a standard regimen (either subsequently or simultaneously) is necessary to achieve the therapeutic benefit. However, co-delivery using a single carrier could give an additional advantage of similar biodistribution profile of the loaded agents. While much research has been carried out in this field in recent years, challenges involved in designing combination formulations including efficient coloading, stability, appropriate biodistribution and target specificity have hampered their clinical translation. This article highlights current aspects of nano-carriers used for co-delivery of small molecules and genes to treat cancer.

Multivalent Aptamer-RNA Conjugates for Simple and Efficient Delivery of Doxorubicin/siRNA into Multidrug-Resistant Cells

Multivalent aptamer-siRNA conjugates containing multiple mucin-1 aptamers and BCL2-specific siRNA are synthesized, and doxorubicin, an anthracycline anticancer drug, is loaded into these conjugates through intercalation with nucleic acids. These doxorubicin-incorporated multivalent aptamer-siRNA conjugates are transfected to mucin-1 overexpressing MCF-7 breast cancer cells and their multidrug-resistant cell lines. Doxorubicin-incorporated multivalent aptamer-siRNA conjugates exert promising anticancer effects, such as activation of caspase-3/7 and decrease of cell viability, on multidrug-resistant cancer cells because of their high intracellular uptake efficiency. Thus, this delivery system is an efficient tool for combination oncotherapy with chemotherapeutics and nucleic acid drugs to overcome multidrug resistance.