Targeting Mitochondria-Located circRNA SCAR Alleviates NASH via Reducing mROS Output.

Mitochondria, which play central roles in immunometabolic diseases, have their own genome. However, the functions of mitochondria-located noncoding RNAs are largely unknown due to the absence of a specific delivery system. By circular RNA (circRNA) expression profile analysis of liver fibroblasts from patients with nonalcoholic steatohepatitis (NASH), we observe that mitochondrial circRNAs account for a considerable fraction of downregulated circRNAs in NASH fibroblasts. By constructing mitochondria-targeting nanoparticles, we observe that Steatohepatitis-associated circRNA ATP5B Regulator (SCAR), which is located in mitochondria, inhibits mitochondrial ROS (mROS) output and fibroblast activation. circRNA SCAR, mediated by PGC-1α, binds to ATP5B and shuts down mPTP by blocking CypD-mPTP interaction. Lipid overload inhibits PGC-1α by endoplasmic reticulum (ER) stress-induced CHOP. In vivo, targeting circRNA SCAR alleviates high fat diet-induced cirrhosis and insulin resistance. Clinically, circRNA SCAR is associated with steatosis-to-NASH progression. Collectively, we identify a mitochondrial circRNA that drives metaflammation and serves as a therapeutic target for NASH.

LCDR regulates the integrity of lysosomal membrane by hnRNP K-stabilized LAPTM5 transcript and promotes cell survival.

Lysosome plays important roles in cellular homeostasis, and its dysregulation contributes to tumor growth and survival. However, the understanding of regulation and the underlying mechanism of lysosome in cancer survival is incomplete. Here, we reveal a role for a histone acetylation-regulated long noncoding RNA termed lysosome cell death regulator (LCDR) in lung cancer cell survival, in which its knockdown promotes apoptosis. Mechanistically, LCDR binds to heterogenous nuclear ribonucleoprotein K (hnRNP K) to regulate the stability of the lysosomal-associated protein transmembrane 5 (LAPTM5) transcript that maintains the integrity of the lysosomal membrane. Knockdown of LCDR, hnRNP K, or LAPTM5 promotes lysosomal membrane permeabilization and lysosomal cell death, thus consequently resulting in apoptosis. LAPTM5 overexpression or cathepsin B inhibitor partially restores the effects of this axis on lysosomal cell death in vitro and in vivo. Similarly, targeting LCDR significantly decreased tumor growth of patient-derived xenografts of lung adenocarcinoma (LUAD) and had significant cell death using nanoparticles (NPs)-mediated systematic short interfering RNA delivery. Moreover, LCDR/hnRNP K/LAPTM5 are up-regulated in LUAD tissues, and coexpression of this axis shows the increased diagnostic value for LUAD. Collectively, we identified a long noncoding RNA that regulates lysosome function at the posttranscriptional level. These findings shed light on LCDR/hnRNP K/LAPTM5 as potential therapeutic targets, and targeting lysosome is a promising strategy in cancer treatment.

Remodeling of Mitochondrial Metabolism by a Mitochondria-Targeted RNAi Nanoplatform for Effective Cancer Therapy.

Emerging evidence has demonstrated the significant contribution of mitochondrial metabolism dysfunction to promote cancer development and progression. Aberrant expression of mitochondrial genome (mtDNA)-encoded proteins widely involves mitochondrial metabolism dysfunction, and targeted regulation of their expression can be an effective strategy for cancer therapy, which however is challenged due to the protection by the mitochondrial double membrane. Herein, a mitochondria-targeted RNAi nanoparticle (NP) platform for effective regulation of mitochondrial metabolism and breast cancer (BCa) therapy is developed. This nanoplatform is composed of a hydrophilic polyethylene glycol (PEG) shell, a hydrophobic poly(2-(diisopropylamino)ethyl methacrylate) (PDPA) core, and charged-mediated complexes of mitochondria-targeting and membrane-penetrating peptide amphiphile (MMPA) and small interfering RNA (siRNA) embedded in the core. After tumor accumulation and internalization by tumor cells, these NPs can respond to the endosomal pH to expose the MMPA/siRNA complexes, which can specifically transport siRNA into the mitochondria to down-regulate mtDNA-encoded protein expression (e.g., ATP6 and CYB). More importantly, because ATP6 down-regulation can suppress ATP production and enhance reactive oxygen species (ROS) generation to induce mitochondrial damage and mtDNA leakage into tumor tissues, the NPs can combinatorially inhibit tumor growth via suppressing ATP production and repolarizing tumor-associated macrophages (TAMs) into tumor-inhibiting M1-like macrophages by mtDNA.

Excessive fatty acids activate PRMT5/MDM2/Drosha pathway to regulate miRNA biogenesis and lipid metabolism.

BACKGROUND: Excessive fatty acids in the liver lead to the accumulation of lipotoxic lipids and then cellular stress to further evoke the related disease, like non-alcoholic fatty liver disease (NAFLD). As reported, fatty acid stimulation can cause some specific miRNA dysregulation, which caused us to investigate the relationship between miRNA biogenesis and fatty acid overload. METHODS: Gene expression omnibus (GEO) dataset analysis, miRNA-seq, miRNA cleavage assay, RT-qPCR, western blotting, immunofluorescence and co-immunoprecipitation (co-IP) were used to reveal the change of miRNAs under pathological status and explore the relevant mechanism. High fat, high fructose, high cholesterol (HFHFrHC) diet-fed mice transfected with AAV2/8-shDrosha or AAV2/8-shPRMT5 were established to investigate the in vivo effects of Drosha or PRMT5 on NAFLD phenotype. RESULTS: We discovered that the cleavage of miRNAs was inhibited by analysing miRNA contents and detecting some representative pri-miRNAs in multiple mouse and cell models, which was further verified by the reduction of the Microprocessor activity in the presence of palmitic acid (PA). In vitro, PA could induce Drosha, the core RNase III in the Microprocessor complex, degrading through the proteasome-mediated pathway, while in vivo, knockdown of Drosha significantly promoted NAFLD to develop to a more serious stage. Mechanistically, our results demonstrated that PA can increase the methyltransferase activity of PRMT5 to degrade Drosha through MDM2, a ubiquitin E3 ligase for Drosha. The above results indicated that PRMT5 may be a critical regulator in lipid metabolism during NAFLD, which was confirmed by the knocking down of PRMT5 improved aberrant lipid metabolism in vitro and in vivo. CONCLUSIONS: We first demonstrated the relationship between miRNA dosage and NAFLD and proved that PA can activate the PRMT5-MDM2-Drosha signalling pathway to regulate miRNA biogenesis.

LARAI portal provides a safe method for lateral meniscus repair: three-dimensional computed tomography and cadaveric assessment.

BACKGROUND: Lateral, All-Round and All-Inside (LARAI) portal is a viewing or working portal for observing and repairing the lesions of the lateral meniscus. However, there are safety concerns about popliteal artery (PA) injuries during the procedure. This study aimed to assess the safe distance between the trajectory of the LARAI portal and PA. MATERIALS AND METHODS: Both three-dimensional computed tomography (3D-CT) and cadavers were used to simulate the LARAI portal trajectory. In the 3D-CT study, between January 2020 and September 2020, 45 participants who underwent computed tomography angiography were included in the study. The shortest distance from the PA to the simulated trajectory needle (PS) was measured using 3D-CT. Mean -3SD -2 was calculated to assess the safety of the LARAI portal trajectory. If this value was more than zero, the trajectory was considered "safe." In the cadaveric study, lower limbs from seven fresh-frozen cadavers were used to establish the "safe" trajectories of the LARAI portal, and the PS was measured. RESULTS: In the 3D-CT study, the longest PS (P < 0.001) was found 20 mm lateral to the edge of the patellar tendon trajectory at 0 mm from the posterior cruciate ligament (PCL). Safe trajectories were also found 10 mm, 15 mm, and 20 mm lateral to the edge of the patellar tendon at 0 mm from the PCL, as well as the 20 mm lateral to the edge of the patellar tendon at 3 mm from the PCL. The cadaveric study showed that the average PS of all safe trajectories closely adjoined to PCL was greater than 14 mm. CONCLUSIONS: The LARAI portal trajectory in the "figure of four" is safe, and the optimal insertion point is 10-20 mm lateral to the edge of the patellar tendon and closely adjoined to the posterolateral margin of the PCL at knee joint line level. LEVEL OF EVIDENCE: Level IV.

HMGN4 plays a key role in STAT3-mediated oncogenesis of triple-negative breast cancer.

High-mobility group nucleosome-binding domain 4 (HMGN4) exerts biological functions by regulating gene transcription through binding with nucleosome. As a new epigenetic regulator discovered in 2001, its biological functions have not been clarified. HMGN4 belongs to HMGNs family, in which HMGN1, 2 and 5 have been reported to play roles in oncogenesis of various cancers. However, it is reported that HMGN4 was associated with thyroid and liver cancer. In this study, we discovered for the first time that HMGN4 was highly expressed in human triple-negative breast cancer (TNBC), based on the analysis of the TCGA database. Moreover, we found that HMGN4 controlled the proliferation of human TNBC cells both in vitro and in vivo. Mechanistically, the positive correlation occurred between HMGN4 and STAT3 downstream genes while HMGN4 played an indispensable role in constitutively active STAT3 (STAT3C) induced colony formation. Interestingly, we reported that STAT3 regulated HMGN4 transcription as its transcriptional factor by chromatin immunoprecipitation and HMGN4 promoter-luc assays. That is to say, there is a feed-forward signaling circuit between HMGN4 and STAT3, which might control TNBC cell growth. Finally, we proved that the interference of HMGN4 by nanovehicle-packaged siRNA may be a potentially effective approach in TNBC treatment. In summary, our findings not only identified a novel regulator in TNBC cell proliferation but also revealed the mechanism by which HMGN4 acted as a downstream gene of STAT3 to participate in the STAT3 pathway, which indicated that HMGN4 was likely to be a potential novel target for anti-TNBC therapy.

Biomedical Applications of a Novel Class of High-Affinity Peptides.

Most therapeutic peptides available on the market today are naturally occurring hormones or protein fragments that were serendipitously discovered to possess therapeutic effects. However, the limited repertoire of available natural resources presents difficulties for the development of new peptide drug candidates. Traditional peptides possess several shortcomings that must be addressed for biomedical applications, including relatively low affinity or specificity toward biological targets compared to antibody- and protein scaffold-based affinity molecules, poor in vivo stability owing to rapid enzymatic degradation, and rapid clearance from circulation owing to their small size. Going forward, it will be increasingly important for scientists to develop novel classes of high-affinity and -specificity peptides against desired targets that mitigate these limitations while remaining compatible with pharmaceutical manufacturing processes. Recently, several highly constrained, artificial cyclic peptides have emerged as platforms capable of generating high-affinity peptide binders against various disease-associated protein targets by combining with phage or mRNA display method, some of which have entered clinical trials. In contrast, although linear peptides are relatively easy to synthesize cost-effectively and modify site-specifically at either N- or C-termini compared to cyclic peptides, there have been few linear peptide-based platforms that can provide high-affinity and -specificity peptide binders.In this Account, we describe the creation and development of a novel class of high-affinity peptides, termed "aptide"-from the Latin word "aptus" meaning "to fit" and "peptide"-and summarize their biomedical applications. In the first part, we consider the design and creation of aptides, with a focus on their unique structural features and binding mode, and address screening and identification of target protein-specific aptides. We also discuss advantages of the aptide platform over ordinary linear peptides lacking preorganized structures in terms of the affinity and specificity of identified peptide binders against target molecules. In the second part, we describe the potential biomedical applications of various target-specific aptides, ranging from imaging and therapy to theranostics, according to the types of aptides and diseases. We show that certain aptides can not only bind to a target protein but also inhibit its biological function, thereby showing potential as therapeutics per se. Further, aptides specific for cancer-associated protein antigens can be used as escort molecules or targeting ligands for delivery of chemotherapeutics, cytokine proteins, and nanomedicines, such as liposomes and magnetic particles, to tumors, thereby substantially improving therapeutic effects. Finally, we present a strategy capable of overcoming the critical issue of short blood circulation time associated with most peptides by constructing a hybrid system between an aptide and a hapten cotinine-specific antibody.

Nanoparticle-Mediated Inhibition of Mitochondrial Glutaminolysis to Amplify Oxidative Stress for Combination Cancer Therapy.

Selective amplification of reactive oxygen species (ROS) generation in tumor cells has been recognized as an effective strategy for cancer therapy. However, an abnormal tumor metabolism, especially the mitochondrial glutaminolysis, could promote tumor cells to generate high levels of antioxidants (e.g., glutathione) to evade ROS-induced damage. Here, we developed a tumor-targeted nanoparticle (NP) platform for effective breast cancer therapy via combining inhibition of mitochondrial glutaminolysis and chemodynamic therapy (CDT). This NP platform is composed of bovine serum albumin (BSA), ferrocene, and purpurin. After surface decoration with a tumor-targeting aptamer and then intravenous administration, this NP platform could target tumor cells and release ferrocene to catalyze hydrogen peroxide (H2O2) into the hydroxyl radical (·OH) for CDT. More importantly, purpurin could inhibit mitochondrial glutaminolysis to concurrently prevent the nutrient supply for tumor cells and disrupt intracellular redox homeostasis for enhanced CDT, ultimately leading to the combinational inhibition of tumor growth.

New PCSK9 inhibitor miR-552-3p reduces LDL-C via enhancing LDLR in high fat diet-fed mice.

PCSK9 has emerged as a promising new therapeutic target for hyperlipidemia. The efficacy of PCSK9 siRNA in clinic trials clues the feasibility of exploring more PCSK9 inhibitors based on genetic inhibition in the treatment of hyperlipidemia. MicroRNAs (miRNAs) as a class of endogenous non-coding small RNAs can regulate genes at transcriptional and/or translational level. Here, we screened miRNAs from the prediction of TargetScan database with possible inhibitory activities in PCSK9 protein level via AlphaLISA and Western blotting, in which miR-552-3p was selected out for its strongest inhibitory effect. MiR-552-3p could bind to the 3' untranslated region (3'-UTR) of PCSK9 to inhibit translation and interact with the promoter of PCSK9 to suppress transcription. Further in vitro and in vivo experiments proved the effects of miR-552-3p on PCSK9 and downstream effectors: it could increase LDLR protein level, promote LDL-C uptake in HepG2 cells and lower serum LDL-C in high fat diet (HFD)-fed mice. In conclusion, our findings firstly identified miR-552-3p as a new PCSK9 inhibitor with the dual-inhibition mechanism, which suggested the possible application of miR-552-3p in the treatment of hyperlipidemia.

Dual Hypoxia-Targeting RNAi Nanomedicine for Precision Cancer Therapy.

As a hallmark of solid tumors, hypoxia promotes tumor growth, metastasis, and therapeutic resistance by regulating the expression of hypoxia-related genes. Hypoxia also represents a tumor-specific stimulus that has been exploited for the development of bioreductive prodrugs and advanced drug delivery systems. Cell division cycle 20 (CDC20) functions as an oncogene in tumorigenesis, and we demonstrated the significant upregulation of CDC20 mRNA in the tumor vs paratumor tissues of breast cancer patients and its positive correlation with tumor hypoxia. Herein, a hypoxia-responsive nanoparticle (HRNP) was developed by self-assembly of the 2-nitroimidazole-modified polypeptide and cationic lipid-like compound for delivery of siRNA to specifically target CDC20, a hypoxia-related protumorigenic gene, in breast cancer therapy. The delivery of siCDC20 by HRNPs sufficiently silenced the expression of CDC20 and exhibited potent antitumor efficacy. We expect that this strategy of targeting hypoxia-correlated protumorigenic genes by hypoxia-responsive RNAi nanoparticles may provide a promising approach in cancer therapy.

Stimuli-Responsive Polymer-Prodrug Hybrid Nanoplatform for Multistage siRNA Delivery and Combination Cancer Therapy.

Nanoparticles (NPs) formulated with cationic lipids and/or polymers have shown substantial potential for systemic delivery of RNA therapeutics such as small interfering RNA (siRNA) for the treatment of cancer and other diseases. While both cationic lipids and polymers have demonstrated the promise to facilitate siRNA encapsulation and endosomal escape, they could also hamper cytosolic siRNA release due to charge interaction and induce potential toxicities. Herein, a unique polymer-prodrug hybrid NP platform was developed for multistage siRNA delivery and combination cancer therapy. This NP system is composed of (i) a hydrophilic polyethylene glycol (PEG) shell, (ii) a hydrophobic NP core made with a tumor microenvironment (TME) pH-responsive polymer, and (iii) charge-mediated complexes of siRNA and amphiphilic cationic mitoxantrone (MTO)-based prodrug that are encapsulated in the NP core. After intravenous administration, the long-circulating NPs accumulate in tumor tissues and then rapidly release the siRNA-prodrug complexes via TME pH-mediated NP disassociation for subsequent tissue penetration and cytosolic transport. With the overexpressed esterase in tumor cells to hydrolyze the amphiphilic structure of the prodrug and thereby induce destabilization of the siRNA-prodrug complexes, the therapeutic siRNA and anticancer drug MTO can be efficiently released in the cytoplasm, ultimately leading to the combinational inhibition of tumor growth via concurrent RNAi-mediated gene silencing and MTO-mediated chemotherapy.

Nanostructure Engineering by Simple Tuning of Lipid Combinations.

Structural morphology is the key parameter for efficacy of nanomedicine. To date, lipid-based nanomaterial has been the most widely used material in nanomedicine and many other biomedical applications. However, to the best of our knowledge, there has not been an in-depth or systematic investigation of the structure-function relationship of lipid-based nanostructures. In this report, we investigated the formulation of novel lipid-based nanostructures via simple tuning of lipid combinations. To prove this concept, we used a combination of various ratios of simple and common phospholipids with different chain lengths (14-carbon chain DMPC: 6-carbon chain DHPC) to find out whether a myriad of novel lipid nanostructures could be obtained. Interestingly, many combinations resulted in distinct lipid nanostructures. Drug encapsulation tests confirmed that they are able to load large amounts of drugs for biological application. In vivo anti-tumor efficacy revealed that certain lipid nanostructures possessed superior tumor retardation effects.

Dynamic Liquid Surface Enhanced Raman Scattering Platform Based on Soft Tubular Microfluidics for Label-Free Cell Detection.

Cell detection is of great significance for biomedical research. Surface enhanced Raman scattering (SERS) has been widely applied to the detection of cells. However, there is still a lack of a general, low-cost, rapid, and sensitive SERS method for cell detection. Herein, a dynamic liquid SERS platform, which combines label-free SERS technique with soft tubular microfluidics for cell detection, is proposed. Compared with common static solid and static liquid measurement, the dynamic liquid SERS platform can present dynamical mixing, precise control of the mixing time, and continuous spectra collection. By characterizing the model molecules, the proposed dynamic liquid SERS platform has successfully demonstrated good stability and repeatability with 1.90% and 4.98% relative standard deviation (RSD), respectively. Three cell lines including one normal breast cell line (MCF-10A) and two breast cancer cell lines (MCF-7 and MDA-MB-231) were investigated in this platform. 270 cell spectra were selected as the training set for the classification of the models based on the K-Nearest Neighbor (K-NN) algorithm. In three independent experiments, three types of cells were identified by a test set containing 180 cell spectra with sensitivities above 83.3% and specificities above 91.6%. The accuracy was 94.1 ± 1.14% among three independent cell identifications. The dynamic liquid SERS platform has shown higher signal intensity, better repeatability, less pretreatment, and obtainment of more spectra with less time consumption. It will be a powerful detection tool in the area of cell research, clinical diagnosis, and food safety.

Theranostic near-infrared fluorescent nanoplatform for imaging and systemic siRNA delivery to metastatic anaplastic thyroid cancer.

Anaplastic thyroid cancer (ATC), one of the most aggressive solid tumors, is characterized by rapid tumor growth and severe metastasis to other organs. Owing to the lack of effective treatment options, ATC has a mortality rate of ∼100% and median survival of less than 5 months. RNAi nanotechnology represents a promising strategy for cancer therapy through nanoparticle (NP) -mediated delivery of RNAi agents (e.g., siRNA) to solid tumors for specific silencing of target genes driving growth and/or metastasis. Nevertheless, the clinical success of RNAi cancer nanotherapies remains elusive in large part because of the suboptimal systemic siRNA NP delivery to tumors and the fact that tumor heterogeneity produces variable NP accumulation and thus, therapeutic response. To address these challenges, we here present an innovative theranostic NP platform composed of a near-infrared (NIR) fluorescent polymer for effective in vivo siRNA delivery to ATC tumors and simultaneous tracking of the tumor accumulation by noninvasive NIR imaging. The NIR polymeric NPs are small (∼50 nm), show long blood circulation and high tumor accumulation, and facilitate tumor imaging. Systemic siRNA delivery using these NPs efficiently silences the expression of V-Raf murine sarcoma viral oncogene homolog B (BRAF) in tumor tissues and significantly suppresses tumor growth and metastasis in an orthotopic mouse model of ATC. These results suggest that this theranostic NP system could become an effective tool for NIR imaging-guided siRNA delivery for personalized treatment of advanced malignancies.

Redox-Responsive Nanoparticle-Mediated Systemic RNAi for Effective Cancer Therapy.

Biodegradable polymeric nanoparticles (NPs) have demonstrated significant potential to improve the systemic delivery of RNA interference (RNAi) therapeutics, such as small interfering RNA (siRNA), for cancer therapy. However, the slow and inefficient siRNA release inside tumor cells generally observed for most biodegradable polymeric NPs may result in compromised gene silencing efficacy. Herein, a biodegradable and redox-responsive NP platform, composed of a solid poly(disulfide amide) (PDSA)/cationic lipid core and a lipid-poly(ethylene glycol) (lipid-PEG) shell for systemic siRNA delivery to tumor cells, is developed. This newly generated NP platform can efficiently encapsulate siRNA under extracellular environments and can respond to the highly concentrated glutathione (GSH) in the cytoplasm to induce fast intracellular siRNA release. By screening a library of PDSA polymers with different structures and chain lengths, the optimized NP platform shows the unique features of i) long blood circulation, ii) high tumor accumulation, iii) fast GSH-triggered intracellular siRNA release, and iv) exceptionally effective gene silencing. Together with the facile polymer synthesis technique and robust NP formulation enabling scale-up, this new redox-responsive NP platform may become an effective tool for RNAi-based cancer therapy.

Tumor Microenvironment-Responsive Multistaged Nanoplatform for Systemic RNAi and Cancer Therapy.

While RNA interference (RNAi) therapy has demonstrated significant potential for cancer treatment, the effective and safe systemic delivery of RNAi agents such as small interfering RNA (siRNA) into tumor cells in vivo remains challenging. We herein reported a unique multistaged siRNA delivery nanoparticle (NP) platform, which is comprised of (i) a polyethylene glycol (PEG) surface shell, (ii) a sharp tumor microenvironment (TME) pH-responsive polymer that forms the NP core, and (iii) charge-mediated complexes of siRNA and tumor cell-targeting- and penetrating-peptide-amphiphile (TCPA) that are encapsulated in the NP core. When the rationally designed, long circulating polymeric NPs accumulate in tumor tissues after intravenous administration, the targeted siRNA-TCPA complexes can be rapidly released via TME pH-mediated NP disassembly for subsequent specific targeting of tumor cells and cytosolic transport, thus achieving efficient gene silencing. In vivo results further demonstrate that the multistaged NP delivery of siRNA against bromodomain 4 (BRD4), a recently discovered target protein that regulates the development and progression of prostate cancer (PCa), can significantly inhibit PCa tumor growth.

Antimonene Quantum Dots: Synthesis and Application as Near-Infrared Photothermal Agents for Effective Cancer Therapy.

Photothermal therapy (PTT) has shown significant potential for cancer therapy. However, developing nanomaterials (NMs)-based photothermal agents (PTAs) with satisfactory photothermal conversion efficacy (PTCE) and biocompatibility remains a key challenge. Herein, a new generation of PTAs based on two-dimensional (2D) antimonene quantum dots (AMQDs) was developed by a novel liquid exfoliation method. Surface modification of AMQDs with polyethylene glycol (PEG) significantly enhanced both biocompatibility and stability in physiological medium. The PEG-coated AMQDs showed a PTCE of 45.5 %, which is higher than many other NMs-based PTAs such as graphene, Au, MoS2 , and black phosphorus (BP). The AMQDs-based PTAs also exhibited a unique feature of NIR-induced rapid degradability. Through both in vitro and in vivo studies, the PEG-coated AMQDs demonstrated notable NIR-induced tumor ablation ability. This work is expected to expand the utility of 2D antimonene (AM) to biomedical applications through the development of an entirely novel PTA platform.

Fabrication of Alginate/Calcium Carbonate Hybrid Microparticles for Synergistic Drug Delivery.

A hybrid drug delivery system coloaded with different drugs for synergistic drug delivery was developed. Alginate/calcium carbonate (CaCO3) hybrid microparticles (MPs) were fabricated via a facile coprecipitation method under mild conditions without using any organic solvent and surfactant. Due to the incorporation of negatively charged alginate chains onto the surface, the obtained hybrid MPs with spherical morphology showed good colloidal stability in an aqueous solution. An antitumor drug (doxorubicin, DOX) and a drug resistance reversal agent (verapamil, VP) were coloaded in the hybrid MPs simultaneously to obtain dual-drug-loaded MPs (DOX/VP/MP). Due to the presence of inorganic CaCO3 (∼54 wt%), the drugs could be loaded in the hybrid MPs with high encapsulation efficiency and the drug release could be effectively sustained. The cell growth inhibition of the drug-loaded MPs was evaluated in HeLa cells. An in vitro study showed DOX/VP/MP exhibited higher cell growth inhibition as compared with DOX monodrug-loaded MPs (DOX/MP). These results suggest the hybrid MPs can potentially be used as a synergistic drug delivery platform for cancer chemotherapy.

Ultra-pH-Responsive and Tumor-Penetrating Nanoplatform for Targeted siRNA Delivery with Robust Anti-Cancer Efficacy.

RNA interference (RNAi) gene silencing technologies have shown significant potential for treating various diseases, including cancer. However, clinical success in cancer therapy remains elusive, mainly owing to suboptimal in vivo delivery of RNAi therapeutics such as small interference RNA (siRNA) to tumors. Herein, we developed a library of polymers that respond to a narrow pH change (ultra-pH-responsive), and demonstrated the utility of these materials in targeted and deep tumor-penetrating nanoparticle (NP) for in vivo RNAi. The new NP platform is mainly composed of the following key components: i) internalizing RGD (iRGD) to enhance tumor targeting and tissue penetration; ii) polyethylene glycol (PEG) chains to prolong blood circulation; and iii) sharp pH-responsive hydrophobic polymer to improve endosome escape. Through systematic studies of structure-function relationship, the optimized RNAi NPs (<70 nm) showed efficient gene silencing and significant inhibition of tumor growth with negligible toxicities in vivo.

Hydrophobic Cysteine Poly(disulfide)-based Redox-Hypersensitive Nanoparticle Platform for Cancer Theranostics.

Selective tumor targeting and drug delivery are critical for cancer treatment. Stimulus-sensitive nanoparticle (NP) systems have been designed to specifically respond to significant abnormalities in the tumor microenvironment, which could dramatically improve therapeutic performance in terms of enhanced efficiency, targetability, and reduced side-effects. We report the development of a novel L-cysteine-based poly (disulfide amide) (Cys-PDSA) family for fabricating redox-triggered NPs, with high hydrophobic drug loading capacity (up to 25 wt% docetaxel) and tunable properties. The polymers are synthesized through one-step rapid polycondensation of two nontoxic building blocks: L-cystine ester and versatile fatty diacids, which make the polymer redox responsive and give it a tunable polymer structure, respectively. Alterations to the diacid structure could rationally tune the physicochemical properties of the polymers and the corresponding NPs, leading to the control of NP size, hydrophobicity, degradation rate, redox response, and secondary self-assembly after NP reductive dissociation. In vitro and in vivo results demonstrate these NPs' excellent biocompatibility, high selectivity of redox-triggered drug release, and significant anticancer performance. This system provides a promising strategy for advanced anticancer theranostic applications.