Biomimetic Nano-Drug Delivery System: An Emerging Platform for Promoting Tumor Treatment.

With the development of nanotechnology, nanoparticles (NPs) have shown broad prospects as drug delivery vehicles. However, they exhibit certain limitations, including low biocompatibility, poor physiological stability, rapid clearance from the body, and nonspecific targeting, which have hampered their clinical application. Therefore, the development of novel drug delivery systems with improved biocompatibility and high target specificity remains a major challenge. In recent years, biofilm mediated biomimetic nano-drug delivery system (BNDDS) has become a research hotspot focus in the field of life sciences. This new biomimetic platform uses bio-nanotechnology to encapsulate synthetic NPswithin biomimetic membrane, organically integrating the low immunogenicity, low toxicity, high tumor targeting, good biocompatibility of the biofilm with the adjustability and versatility of the nanocarrier, and shows promising applications in the field of precision tumor therapy. In this review, we systematically summarize the new progress in BNDDS used for optimizing drug delivery, providing a theoretical reference for optimizing drug delivery and designing safe and efficient treatment strategies to improve tumor treatment outcomes.

Biomimetic liposomal nanozymes improve breast cancer chemotherapy with enhanced penetration and alleviated hypoxia.

BACKGROUND: Doxorubicin (Dox) has been recommended in clinical guidelines for the standard-of-care treatment of breast cancer. However, Dox therapy faces challenges such as hypoxia, acidosis, H2O2-rich conditions and condensed extracellular matrix in TME as well as low targeted ability. METHODS: We developed a nanosystem H-MnO2-Dox-Col NPs based on mesoporous manganese dioxide (H-MnO2) in which Dox was loaded in the core and collagenase (Col) was wrapped in the surface. Further the H-MnO2-Dox-Col NPs were covered by a fusion membrane (MP) of inflammation-targeted RAW264.7 cell membrane and pH-sensitive liposomes to form biomimetic MP@H-MnO2-Dox-Col for in vitro and in vivo study. RESULTS: Our results shows that MP@H-MnO2-Dox-Col can increase the Dox effect with low cardiotoxicity based on multi-functions of effective penetration in tumor tissue, alleviating hypoxia in TME, pH sensitive drug release as well as targeted delivery of Dox. CONCLUSIONS: This multifunctional biomimetic nanodelivery system exhibited antitumor efficacy in vivo and in vitro, thus having potential for the treatment of breast cancer.

A ferroptosis-inducing biomimetic nanocomposite for the treatment of drug-resistant prostate cancer.

Second-generation androgen receptor (AR) inhibitors such as enzalutamide are the first-line treatments for castration-resistant prostate cancer (CRPC). Resistance to enzalutamide will greatly increase the difficulty of prostate cancer treatment and reduce the survival time of patients. However, drug-resistant cancer cells seem to be more sensitive to ferroptosis. Therefore, we constructed a biomimetic tumor-targeting magnetic lipid nanoparticle (t-ML) to codeliver dihomo-γ-linolenic acid (DGLA) and 2,4-dienoyl-CoA reductase 1 (DECR1) siRNA (t-ML@DGLA/siDECR1). DGLA is a dietary polyunsaturated fatty acid (PUFA), while DECR1 is overexpressed in prostate cancer and can inhibit the generation of PUFAs. The combination of DGLA and siDECR1 can efficiently induce ferroptosis by peroxidation of PUFAs, which has been verified both in vitro and in vivo. With the assistance of an external magnet, t-ML showed good tumor targeting ability and biocompatibility, and t-ML@DGLA/siDECR1 exhibited significant ferroptosis induction and tumor suppression capabilities. Moreover, in a nude mouse model of prostate cancer fed on a high-fat diet (HFD), there was no distant organ metastasis when the tumor-bearing mice were treated with t-ML@DGLA/siDECR1 and an external magnet, with upregulated PUFAs and downregulated monounsaturated fatty acids (MUFAs). Hence, this study has broadened the way of treating drug-resistant prostate cancer based on ferroptosis induction.

Co-delivery of the autophagy inhibitor si-Beclin1 and the doxorubicin nano-delivery system for advanced prostate cancer treatment.

Resistance to apoptosis is a key mechanism underlying how cancer cells evade tumor therapy. Autophagy can prevent anticancer drug-induced apoptosis and promote tumor resistance. The purpose of this study was to improve the sensitivity and efficacy of chemotherapeutic drugs through the inhibition of autophagy. Hydrophobic doxorubicin-hydrazone-caproyl-maleimide (DOX-EMCH) and autophagy-inhibiting si-Beclin1 were simultaneously delivered via the amphiphilic peptide micelle system (Co-PMs) using poly(L-arginine)-poly(L-histidine)-DOX-EMCH as the copolymer building unit. The constructed micelle system promoted the escape of si-Beclin1 from endosomes and the release of DOX into the nucleus. The Co-PMs exhibited 2.7-fold higher cytotoxicity and proapoptotic ability in PC3 cells than DOX treatment alone, demonstrating that si-Beclin1 could inhibit the autophagic activity of prostate cancer (PCa) cells by targeting the type III PI3K pathway and enhance the sensitivity of the cells to the chemotherapeutic drug DOX. In addition, the peptide micelles successfully passively targeted DOX and si-Beclin1 to the tumor tissue. Compared with DOX or si-Beclin1 treatment alone, the Co-PMs showed a 3.4-fold greater tumor inhibitory potential in vivo, indicative of a significant antiproliferative effect. Our results suggested that the Co-PMs developed in this study have the potential to combine autophagy inhibition and chemotherapy in cancer treatment, especially for PCa.

γ-Cyclodextrin metal-organic framework as a carrier to deliver triptolide for the treatment of hepatocellular carcinoma.

Triptolide (TPL) has been employed to treat hepatocellular carcinoma (HCC). However, the poor water solubility of TPL restricts its applications. Therefore, we prepared TPL-loaded cyclodextrin-based metal-organic framework (TPL@CD-MOF) to improve the solubility and bioavailability of TPL, thus enhancing the anti-tumor effect on HCC. The BET surface and the pore size of TPL@CD-MOF were 10.4 m2·g-1 and 1.1 nm, respectively. The results of XRD indicated that TPL in TPL@CD-MOF was encapsuled. TPL@CD-MOF showed a slower release than free TPL in vitro. Moreover, the CD-MOF improved the bioavailability of TPL. TPL@CD-MOF showed slightly higher, but statistically significant, anti-tumor efficacy in vitro and in vivo compared to free TPL. In addition, TPL@CD-MOF exhibited a modest improvement of the anti-tumor effects, which may be associated to the enhanced in vivo absorption. Overall, these findings suggested the potential CD-MOF as oral drug delivery carriers for anti-tumor drugs. The process of TPL loading into CD-MOF and its enhanced oral bioavailability and anti-tumor activity.

Erythrocyte-cancer Hybrid Membrane-camouflaged Mesoporous Silica Nanoparticles Loaded with Gboxin for Glioma-targeting Therapy.

OBJECTIVE: The purpose of this research is to formulate a biomimetic drug delivery system, which can selectively target glioblastoma (GBM) to deliver the antitumor agent, Gboxin, a novel Complex V inhibitor. Gboxin can specifically inhibit GBM cell growth but not normal cells. METHODS: In the present study, we utilized red blood cell (RBC) membrane and U251 cell membrane to obtain a hybrid biomimetic membrane (RBC-U), and prepared RBC-U coated Gboxin-loaded mesoporous silica nanoparticles ((MSNs/Gboxin)@[RBC-U]) for GBM chemotherapy. The zeta potential, particle size, and morphology of (MSNs/Gboxin)@[RBC-U] were characterized. The cellular uptake, effect of cells growth inhibition, biocompatibility, and specific self-recognition of nanoparticles were evaluated. RESULTS: The (MSNs/Gboxin)@[RBC-U] was successfully fabricated and possessed high stability in the circulation system. The drug loading of Gboxin was 13.9%. (MSNs/Gboxin)@ [RBC-U] could effectively retain drugs in the physiological environment and released Gboxin rapidly in the tumor cells. Compared to the MSNs/Gboxin, the (MSNs/Gboxin)@[RBC-U] exhibit highly specific self-recognition to the source cell line. Additionally, the (MSNs/Gboxin) @[RBC-U] showed excellent anti-proliferation efficiency (IC50 = 0.21 µg/mL) in the tumor cell model and few side effects in normal cels in vitro. CONCLUSION: The (MSNs/Gboxin)@[RBC-U] exhibited significant anti-cancer effects in vitro and the specific self-recognition to GBM cells. Hence, (MSNs/Gboxin)@[RBC-U] could be a promising delivery system for GBM targeted therapy.

Immunologically modified enzyme-responsive micelles regulate the tumor microenvironment for cancer immunotherapy.

Immune checkpoint blockade has been proven to have great therapeutic potential and has revolutionized the treatment of tumors. However, various limitations remain, including the low response rate of exhausted T cells and mutual regulation of multiple immunosuppressive cell types that compromise the effect of single-target therapy. Nano-delivery systems can be used to regulate the tumor immune microenvironment in favor of immunotherapy. In this study, we constructed a polypeptide-based micellar system that encapsulates an aryl hydrocarbon receptor (AhR) inhibitor (CH223191) conjugated to T cell activator anti-CD28. The inhibition of AhR activation downregulates the fraction of immunosuppressive cells and effectively inhibits tumor cell metastasis. In addition, the combination with co-stimulatory antibodies improves T-cell activation and synergistically enhances the antitumor effect of AhR inhibitors. The micellar system developed in this study represents a novel and effective tumor immunotherapy approach.

Sorafenib and triptolide loaded cancer cell-platelet hybrid membrane-camouflaged liquid crystalline lipid nanoparticles for the treatment of hepatocellular carcinoma.

In addition to early detection, early diagnosis, and early surgery, it is of great significance to use new strategies for the treatment of hepatocellular carcinoma (HCC). Studies showed that the combination of sorafenib (SFN) and triptolide (TPL) could reduce the clinical dose of SFN and maintain good anti-HCC effect. But the solubility of SFN and TPL in water is low and both drugs have certain toxicity. Therefore, we constructed a biomimetic nanosystem based on cancer cell-platelet (PLT) hybrid membrane camouflage to co-deliver SFN and TPL taking advantage of PLT membrane with long circulation functions and tumor cell membrane with homologous targeting. The biomimetic nanosystem, SFN and TPL loaded cancer cell-PLT hybrid membrane-camouflaged liquid crystalline lipid nanoparticles ((SFN + TPL)@CPLCNPs), could simultaneously load SFN and TPL at the molar ratio of SFN to TPL close to 10:1. (SFN + TPL)@CPLCNPs achieved long circulation function and tumor targeting at the same time, promoting tumor cell apoptosis, inhibiting tumor growth, and achieving a better "synergy and attenuation effect", which provided new ideas for the treatment of HCC.

Tumor microenvironment-activated cancer cell membrane-liposome hybrid nanoparticle-mediated synergistic metabolic therapy and chemotherapy for non-small cell lung cancer.

BACKGROUND: Biomimetic nanotechnology-based RNA interference (RNAi) has been successful in improving theranostic efficacy in malignant tumors. Its integration with hybrid biomimetic membranes made of natural cell membranes fused with liposomal membranes is mutually beneficial and extends their biofunctions. However, limited research has focused on engineering such biomimetics to endow them with unique properties and functions, in particular, those essential for a "smart" drug delivery system, such as a tumor microenvironment (TME)-activated multifunctional biomimetic nanoplatform. RESULTS: Herein, we utilized an integrated hybrid nanovesicle composed of cancer cell membranes (Cm) and matrix metallopeptidase 9 (MMP-9)-switchable peptide-based charge-reversal liposome membranes (Lipm) to coat lipoic acid-modified polypeptides (LC) co-loaded with phosphoglycerate mutase 1 (PGAM1) siRNA (siPGAM1) and DTX. The nanovesicle presented a negatively charged coating (citraconic anhydride-grafted poly-L-lysine, PC) in the middle layer for pH-triggered charge conversion functionalization. The established chemotherapeutic drug (DTX) co-delivery system CLip-PC@CO-LC nanoparticles (NPs) have a particle size of ~ 193 nm and present the same surface proteins as the Cm. Confocal microscopy and flow cytometry results indicated a greater uptake of MMP-9-treated CLip-PC@CO-LC NPs compared with that of the CLip-PC@CO-LC NPs without MMP-9 pretreatment. The exposure to MMP-9 activated positively charged cell-penetrating peptides on the surface of the hybrid nanovesicles. Moreover, pH triggered membrane disruption, and redox triggered DTX and siRNA release, leading to highly potent target-gene silencing in glycolysis and chemotherapy with enhanced antiproliferation ability. The biodistribution results demonstrated that the CLip-PC@LC-DiR NPs accumulated in the tumor owing to a combination of long blood retention time, homologous targeting ability, and TME-activated characteristics. The CLip-PC@CO-LC NPs led to more effective tumor growth inhibition than the DTX and free siPGAM1 formulations. CONCLUSIONS: TME-activated cancer cell membrane-liposome integrated hybrid NPs provide an encouraging nanoplatform that combines RNAi with chemotherapy for precise treatment of non-small cell lung cancer.

Regulating the immunosuppressive tumor microenvironment to enhance breast cancer immunotherapy using pH-responsive hybrid membrane-coated nanoparticles.

The combination of an immuno-metabolic adjuvant and immune checkpoint inhibitors holds great promise for effective suppression of tumor growth and invasion. In this study, a pH-responsive co-delivery platform was developed for metformin (Met), a known immuno-metabolic modulator, and short interfering RNA (siRNA) targeting fibrinogen-like protein 1 mRNA (siFGL1), using a hybrid biomimetic membrane (from macrophages and cancer cells)-camouflaged poly (lactic-co-glycolic acid) nanoparticles. To improve the endo-lysosomal escape of siRNA for effective cytosolic siRNA delivery, a pH-triggered CO2 gas-generating nanoplatform was developed using the guanidine group of Met. It can react reversibly with CO2 to form Met-CO2 for the pH-dependent capture/release of CO2. The introduction of Met, a conventional anti-diabetic drug, promotes programmed death-ligand 1 (PD-L1) degradation by activating adenosine monophosphate-activated protein kinase, subsequently blocking the inhibitory signals of PD-L1. As a result, siFGL1 delivery by the camouflaged nanoparticles of the hybrid biomimetic membrane can effectively silence the FGL1 gene, promoting T-cell-mediated immune responses and enhancing antitumor immunity. We found that a combination of PD-L1/programmed death 1 signaling blockade and FGL1 gene silencing exhibited high synergistic therapeutic efficacy against breast cancer in vitro and in vivo. Additionally, Met alleviated tumor hypoxia by reducing oxygen consumption and inducing M1-type differentiation of tumor-related macrophages, which improved the tumor immunosuppressive microenvironment. Our results indicate the potential of hybrid biomimetic membrane-camouflaged nanoparticles and combined Met-FGL1 blockade in breast cancer immunotherapy.

Macrophage-cancer hybrid membrane-coated nanoparticles for targeting lung metastasis in breast cancer therapy.

Cell membrane- covered drug-delivery nanoplatforms have been garnering attention because of their enhanced bio-interfacing capabilities that originate from source cells. In this top-down technique, nanoparticles (NPs) are covered by various membrane coatings, including membranes from specialized cells or hybrid membranes that combine the capacities of different types of cell membranes. Here, hybrid membrane-coated doxorubicin (Dox)-loaded poly(lactic-co-glycolic acid) (PLGA) NPs (DPLGA@[RAW-4T1] NPs) were fabricated by fusing membrane components derived from RAW264.7(RAW) and 4T1 cells (4T1). These NPs were used to treat lung metastases originating from breast cancer. This study indicates that the coupling of NPs with a hybrid membrane derived from macrophage and cancer cells has several advantages, such as the tendency to accumulate at sites of inflammation, ability to target specific metastasis, homogenous tumor targeting abilities in vitro, and markedly enhanced multi-target capability in a lung metastasis model in vivo. The DPLGA@[RAW-4T1] NPs exhibited excellent chemotherapeutic potential with approximately 88.9% anti-metastasis efficacy following treatment of breast cancer-derived lung metastases. These NPs were robust and displayed the multi-targeting abilities of hybrid membranes. This study provides a promising biomimetic nanoplatform for effective treatment of breast cancer metastasis.

Intravenous delivery of enzalutamide based on high drug loading multifunctional graphene oxide nanoparticles for castration-resistant prostate cancer therapy.

BACKGROUND: Enzalutamide (Enz) has shown limited bioavailability via oral administration. Castration-resistant prostate cancer (CRPC) is frequent among patients receiving 18-24 months of androgen deprivation therapy. The nonsteroidal anti-androgen enzalutamide (Enz) used in the treatment of prostate cancer has shown limited bioavailability via oral administration. Therefore, we developed a multifunctional enzalutamide-loaded graphene oxide nanosystem (TP-GQDss/Enz) for CRPC intravenous treatment, with high drug loading efficiency. METHODS: Aminated graphene quantum dots (GQDs) were first cross-linked via disulfide bonds into a graphene quantum dot derivative of approximately 200 nm (GQDss), which was further functionalized with a tumour-targeting peptide and PEG to form TP-GQDss. Enz was loaded into TP-GQDss for in vitro and in vivo study. RESULTS: The results showed that high drug-loading efficiency was achieved by TP-GQDss via π-π electron interaction. TP-GQDss could be rapidly internalized by CRPC cells via endocytosis. Moreover, Enz in TP-GQDss could inhibit the growth of C4-2B and LNCaP prostate cancer cell lines in vitro. Further, TP-GQDss exhibited an enhanced cancer-targeting ability and alleviated the side effects of Enz in vivo. CONCLUSIONS: The multifunctional nanocarrier constructed here could accomplish controlled Enz release and serve as an intravenous therapy platform for CRPC.

Dual-Blockade Immune Checkpoint for Breast Cancer Treatment Based on a Tumor-Penetrating Peptide Assembling Nanoparticle.

Cancer immunotherapy can enhance the antitumor effect of drugs through a combinatorial approach in a synergistic manner. However, the effective targeted delivery of various drugs remains a challenge. We generated a peptide assembling tumor-targeted nanodelivery system based on a breast cancer homing and penetrating peptide for the codelivery of a programmed cell death ligand 1 (PD-L1) small interfering RNA (siRNA) (siPD-L1) and an indoleamine 2,3-dioxygenase inhibitor as a dual blockade of an immune checkpoint. The vector is capable of specifically accumulating in the breast cancer tumor site in a way that allows the siRNA to escape from endosomal vesicles after being endocytosed by tumor cells. The drug within these cells then acts to block tryptophan metabolism. The results showed that locally released siPD-L1 and 1-methyl-dl-tryptophan favor the survival and activation of cytotoxic T lymphocytes, resulting in apoptosis of breast cancer cells. Therefore, this study provides a potential approach for treating breast cancer by blocking immunological checkpoints through the assembly of micelles with functional peptides.

Functional exosome-mediated co-delivery of doxorubicin and hydrophobically modified microRNA 159 for triple-negative breast cancer therapy.

Exosomes (Exo) hold great promise as endogenous nanocarriers that can deliver biological information between cells. However, Exo are limited in terms of their abilities to target specific recipient cell types. We developed a strategy to isolate Exo exhibiting increased binding to integrin αvß3. Binding occurred through a modified version of a disintegrin and metalloproteinase 15 (A15) expressed on exosomal membranes (A15-Exo), which facilitated co-delivery of therapeutic quantities of doxorubicin (Dox) and cholesterol-modified miRNA 159 (Cho-miR159) to triple-negative breast cancer (TNBC) cells, both in vitro and in vivo. The targeted A15-Exo were derived from continuous protein kinase C activation in monocyte-derived macrophages. These cell-derived Exo displayed targeting properties and had a 2.97-fold higher production yield. In vitro, A15-Exo co-loaded with Dox and Cho-miR159 induced synergistic therapeutic effects in MDA-MB-231 cells. In vivo, miR159 and Dox delivery in a vesicular system effectively silenced the TCF-7 gene and exhibited improved anticancer effects, without adverse effects. Therefore, our data demonstrate the synergistic efficacy of co-delivering miR159 and Dox by targeted Exo for TNBC therapy.

A novel macrophage-mediated biomimetic delivery system with NIR-triggered release for prostate cancer therapy.

BACKGROUND: Macrophages with tumor-tropic migratory properties can serve as a cellular carrier to enhance the efficacy of anti neoplastic agents. However, limited drug loading (DL) and insufficient drug release at the tumor site remain the main obstacles in developing macrophage-based delivery systems. In this study, we constructed a biomimetic delivery system (BDS) by loading doxorubicin (DOX)-loaded reduced graphene oxide (rGO) into a mouse macrophage-like cell line (RAW264.7), hoping that the newly constructed BDS could perfectly combine the tumor-tropic ability of macrophages and the photothermal property of rGO. RESULTS: At the same DOX concentration, the macrophages could absorb more DOX/PEG-BPEI-rGO than free DOX. The tumor-tropic capacity of RAW264.7 cells towards RM-1 mouse prostate cancer cells did not undergo significant change after drug loading in vitro and in vivo. PEG-BPEI-rGO encapsulated in the macrophages could effectively convert the absorbed near-infrared light into heat energy, causing rapid release of DOX. The BDS showed excellent anti-tumor efficacy in vivo. CONCLUSIONS: The BDS that we developed in this study had the following characteristic features: active targeting of tumor cells, stimuli-release triggered by near-infrared laser (NIR), and effective combination of chemotherapy and photothermotherapy. Using the photothermal effect produced by PEG-BPEI-rGO and DOX released from the macrophages upon NIR irradiation, MAs-DOX/PEG-BPEI-rGO exhibited a significant inhibitory effect on tumor growth.

Codelivery of miR-4638-5p and Docetaxel Based on Redox-Sensitive Polypeptide Micelles as an Improved Strategy for the Treatment of Castration-Resistant Prostate Cancer.

In this work, we have developed a reducible, self-assembling disulfide cross-linked and peptide-based micelle system for codelivery of miR-4638-5p and DTX to improve the efficacy of castration-resistant prostate cancer (CRPC) therapy. The result showed that DTX in micelles (DTX-VPs) inhibited cell growth and induced apoptosis more effectively than free DTX both in vitro and in vivo. In addition, the DTX and miR-4638-5p loaded micelles (Co-VPs) achieved the most pronounced anticancer effect of all groups. Immunohistochemical analysis indicated that miR-4638-5p in micelle system could effectively downregulate the expression of Kidins220 and further improve the anticancer effect by enhancing tumor cell apoptosis and suppressing tumor cell proliferation. Finally, the bioimaging analysis demonstrated that DIR in micelles (DIR-VPs) showed a higher concentration and a longer retention time in tumor tissue than did free DIR, which indicated an excellent tumor-targeting ability of the micelle system. All these results suggest that codelivery of miR-4638-5p and DTX via polypeptide micelle system has a potential for CRPC treatment.

Aptamer-conjugated multi-walled carbon nanotubes as a new targeted ultrasound contrast agent for the diagnosis of prostate cancer.

Early diagnosis is primarily important for the therapeutic and prognostic outcomes of malignancies including prostate cancer (PCa). However, the visuality and veracity of ultrasound imaging for the diagnosis and prognostic prediction of PCa remains poor at present. In this study, we developed a new nanoultrasound contrast agent by modifying multi-walled carbon nanotubes (MWCNTs) with polyethylene glycol (PEG) and anti-PSMA aptamer. The result showed that the modified MWCNTs offered better visuality and veracity and were able to target PCa cells more effectively as compared with the traditional contrast agent. The zeta potential was about - 38 mv. The length of this contrast agent was about 400 nm and the diameter of it was about 30 nm. The zeta potential, TEM, and FT-IR all proved the successful preparation of the agent. The vitro cytological study revealed good cell uptake and biocompatibility of the new contrast agent. The minimum detection concentration in vitro is 10 µg/ml. The earliest stage of the detection was under the parameters of frequency = 6.0 MHz and medical index = 0.06. Both in vitro and in vivo ultrasound imaging demonstrated that the new nanoultrasound contrast agent had a good development effect, distribution, and metabolism, and may prove to be a good targeted ultrasound contrast agent, especially for PCa.

Functionalized Multi-Walled Carbon Nanotubes for Targeting Delivery of Immunostimulatory CpG Oligonucleotides Against Prostate Cancer.

Immuno-based oncotherapy has been successfully implemented for cancer treatment. In the present study, we developed a Oligodeoxynucleotides (ODNs) containing unmethylated CpG motifs (CpG ODNs) nano-delivery system based on Multi-walled carbon nanotubes (MWCNTs) conjugated with H3R6 polypeptide (MHR-CpG) for prostate cancer immunotherapy. The in vitro and in vivo toxicity data revealed that the prepared MHR showed high biocompatibility. Confocal laser scanning microscopy confirmed that MHR-CpG could specifically target the endosomal TLR9. In addition, the use of MHR enhanced the immunogenicity of CpG in both humoral and cellular immune pathways, as evidenced by the increased expression of CD4+ T-cells, CD8+ T-cells, TNF-α, and IL-6. The in vivo anti-cancer efficacy study on RM-1 tumor-bearing mice demonstrated that MHR-CpG could deliver the immunotherapeutics to the tumor site and the tumor-draining lymph node to suppress tumor growth. These results suggested that MHR-CpG was a promising multifunctional nano system for prostate cancer immunotherapy.

A33 antibody-functionalized exosomes for targeted delivery of doxorubicin against colorectal cancer.

Exosomes have emerged as a promising drug carrier with low immunogenicity, high biocompatibility and delivery efficiency. Here in, we isolated exosomes from A33-positive LIM1215 cells (A33-Exo) and loaded them with doxorubicin (Dox). Furthermore, we coated surface-carboxyl superparamagnetic iron oxide nanoparticles (US) with A33 antibodies (A33Ab-US), expecting that these A33 antibodies on the surface of the nanoparticles could bind to A33-positive exosomes and form a complex (A33Ab-US-Exo/Dox) to target A33-positive colon cancer cells. The results showed that A33Ab-US-Exo/Dox had good binding affinity and antiproliferative effect in LIM1215 cells, as shown by increased uptake of the complex. In vivo study showed that A33Ab-US-Exo/Dox had an excellent tumor targeting ability, and was able to inhibit tumor growth and prolong the survival of the mice with reduced cardiotoxicity. In summary, exosomes functionalized by targeting ligands through coating with high-density antibodies may prove to be a novel delivery system for targeted drugs against human cancers.

Co-delivery of autophagy inhibitor ATG7 siRNA and docetaxel for breast cancer treatment.

The lysosomal degradation pathway of autophagy has a crucial role in protecting cancer cells from multiple endogenous and exogenous stresses, particularly during the pathogenesis of cancer. Accordingly, agents that inhibit autophagy may have broad therapeutic applications. We have developed a novel strategy based on co-delivery of an autophagy related 7 (ATG7) siRNA and docetaxel (DTX) in a crosslinked, reducible, peptide-based micellar system for breast cancer treatment. Our results show that DTX and siATG7 co-treatment exhibited 2.5- and 1.7-fold higher cytotoxicity and apoptosis, respectively, in MCF-7 cells than DTX treatment alone did, which demonstrates that siATG7 enhances the efficacy and apoptotic effect of DTX. Our study showed that breast cancer cell lines differ greatly in their dependency on autophagy under conditions of normal or stress. Furthermore, siATG7 delivery in a micellar system can effectively silence the ATG7 gene, suppress DTX-induced autophagy, and exhibit improved anticancer effects. In addition, DTX in a co-delivery system showed at least a 1.84-fold greater tumor inhibition compared to that of DTX-loaded micelles in vivo. Finally, a Cy5 indicator that was loaded into crosslinked micelles revealed a remarkably high accumulation in tumors, demonstrating excellent tumor targeting ability of the micellar system. Therefore, our research demonstrated the synergistic efficacy of the combination of autophagy inhibition and chemotherapy delivered by polypeptide micelles for breast cancer therapy.