Hybrid Prodrug Nanoparticles with Tumor Penetration and Programmed Drug Activation for Enhanced Chemoresistant Cancer Therapy

Advances in nano-preparations for improving tetrandrine solubility and bioavailability

Tetrandrine (TET) is a natural bis-benzylisoquinoline alkaloid isolated from Stephania species with a wide range of biological and pharmacologic activities; it mainly serves as an anti-inflammatory agent or antitumor adjuvant in clinical applications. However, limitations such as prominent hydrophobicity, severe off-target toxicity, and low absorption result in suboptimal therapeutic outcomes preventing its widespread adoption. Nanoparticles have proven to be efficient devices for targeted drug delivery since drug-carrying nanoparticles can be passively transported to the tumor site by the enhanced permeability and retention (EPR) effects, thus securing a niche in cancer therapies. Great progress has been made in nanocarrier construction for TET delivery due to their outstanding advantages such as increased water-solubility, improved biodistribution and blood circulation, reduced off-target irritation, and combinational therapy. Herein, we systematically reviewed the latest advancements in TET-loaded nanoparticles and their respective features with the expectation of providing perspective and guidelines for future research and potential applications of TET.

Fasting-Mimicking Diet Facilitates Anti-tumor Therapeutic Effects by Nutrient-Sensitive Nanocomposites

Cancer cells support their uncontrolled proliferation primarily by regulating energy metabolism. Inhibiting tumor growth by blocking the supply of nutrients is an effective treatment strategy. Fasting-mimicking diet (FMD), as a low-calorie, low-protein, low-sugar, high-fat diet, can effectively reduce the nutrient supply to tumor cells. However, the significant biological barrier presented by the tumor microenvironment imposes greater demands and challenges for drug design. This study constructs the multifunctional nanocomposite ZnFe2O4@TiO2@CHC@Orl-FA (ZTCOF), which has great potential to overcome the aforementioned drawbacks. ZnFe2O4@TiO2 could produce 1O2 with ultrasound, and stimulate the Fenton-like conversion of endogenous H2O2 to ·OH, achieving a combined therapeutic effect of sonodynamic therapy (SDT) and chemodynamic therapy (CDT). Orl (Orlistat) and CHC (α-cyano-4-hydroxycinnamic acid) not only block tumor cell energy metabolism but also increase sensitivity to reactive oxygen species, enhancing the cytotoxic effect on tumor cells. Furthermore, combining the treatment strategies with FMD condition control can further inhibit cancer cell energy metabolism, achieving significant synergistic anti-tumor therapy. Both in vitro and in vivo experiments confirm that ZTCOF with SDT/CDT/starvation can achieve effective tumor suppression and destruction. This work provides theoretical and technical support for anti-tumor multimodal synergistic therapy.

Ultra-small Janus nanoparticle-induced activation of ferroptosis for synergistic tumor immunotherapy

Ferroptosis induced by lipid peroxide (LPO) accumulation is an effective cell death pathway for cancer therapy. However, how to effectively induce ferroptosis at tumor sites and improve its therapeutic effectiveness remains challenging. Here, MnFe2O4@NaGdF4@NLG919@HA (MGNH) nanocomplex with tumor-specific targeting and TME response is constructed to overcome immunosuppressive tumor microenvironment (TME) to potentiate the curative effect of ferroptosis by coupling the immune checkpoint indoleamine 2,3-dioxygenase (IDO) inhibitor, NLG919, and hyaluronic acid (HA) to novel ultra-small MnFe2O4@NaGdF4 (MG) nanoparticles with a Janus structure. Firstly, tumor site-precise delivery of MG and NLG919 is achieved with HA targeting. Secondly, MG acts as a magnetic resonance imaging contrast agent, which not only has a good photothermal effect to realize tumor photothermal therapy, but also depletes glutathione and catalyzes the production of reactive oxygen species from endogenous H2O2, which effectively promotes the accumulation of LPO and inhibits the expression of glutathione peroxidase 4, achieving enhanced ferroptosis. Thirdly, NLG919 inhibits the differentiation of Tregs by blocking the tryptophan/kynurenine immune escape pathway, thereby reversing immunosuppressive TME together with the Mn2+-activated cGAS-STING pathway. This work contributes new perspectives for the development of novel ultra-small Janus nanoparticles to reshape immunosuppressive TME and ferroptosis activation. STATEMENT OF SIGNIFICANCE: The Janus structured MnFe2O4@NaGdF4@NLG919@HA (MGNH) nanocomplex was synthesized, which can realize the precise delivery of T1/T2 contrast agents MnFe2O4@NaGdF4 (MG) and NLG919 at the tumor site under the ultra-small Janus structural characteristics and targeted molecule HA. The production of ROS, consumption of GSH, and photothermal properties of MGNH make it possible for CDT/PTT activated ferroptosis, and synergistically disrupt and reprogram tumor growth and immunosuppressive tumor microenvironment with NLG919 and Mn2+-mediated activation of cGAS-STING pathway, achieving CDT/PTT/immunotherapy activated by ferroptosis. Meanwhile, ultra-small structural properties of MGNH facilitate subsequent metabolic clearance by the body, allowing for the minimization of potential biotoxicity associated with its prolonged retention.

Therapeutic effects of tetrandrine in inflammatory diseases: a comprehensive review

Inflammation can be triggered by any factor. The primary pathological manifestations can be summarized as the deterioration, exudation, and proliferation of local tissues, which can cause systemic damage in severe cases. Inflammatory lesions are primarily localized but may interact with body systems to cause provocative storms, parenchymal organ lesions, vascular and central nervous system necrosis, and other pathologic responses. Tetrandrine (TET) is a bisbenzylquinoline alkaloid extracted from the traditional Chinese herbal medicine Stephania tetrandra, which has been shown to have significant efficacy in inflammatory conditions such as rheumatoid arthritis, hepatitis, nephritis, etc., through NF-κB, MAPK, ERK, and STAT3 signaling pathways. TET can regulate the body's imbalanced metabolic pathways, reverse the inflammatory process, reduce other pathological damage caused by inflammation, and prevent the vicious cycle. More importantly, TET does not disrupt body's normal immune function while clearing the body's inflammatory state. Therefore, it is necessary to pay attention to its dosage and duration during treatment to avoid unexpected side effects caused by a long half-life. In summary, TET has a promising future in treating inflammatory diseases. The author reviews current therapeutic studies of TET in inflammatory conditions to provide some ideas for subsequent anti-inflammatory studies of TET.

Exploiting Nanomedicine for Cancer Polychemotherapy: Recent Advances and Clinical Applications

The most important limitations of chemotherapeutic agents are severe side effects and the development of multi-drug resistance. Recently, the clinical successes achieved with immunotherapy have revolutionized the treatment of several advanced-stage malignancies, but most patients do not respond and many of them develop immune-related adverse events. Loading synergistic combinations of different anti-tumor drugs in nanocarriers may enhance their efficacy and reduce life-threatening toxicities. Thereafter, nanomedicines may synergize with pharmacological, immunological, and physical combined treatments, and should be increasingly integrated in multimodal combination therapy regimens. The goal of this manuscript is to provide better understanding and key considerations for developing new combined nanomedicines and nanotheranostics. We will clarify the potential of combined nanomedicine strategies that are designed to target different steps of the cancer growth as well as its microenvironment and immunity interactions. Moreover, we will describe relevant experiments in animal models and discuss issues raised by translation in the human setting.

Study of oxygen-deficient W18O49-based drug delivery system readily absorbed through cellular internalization pathways in tumor-targeted chemo-/photothermal therapy

W₁₈O₄₉-mediated photothermal therapy (PTT) is affected by the easily oxidized property and its direct exposure to physiological environment can cause biological events, which limit its development in the biomedical field. Herein, a composite nanoparticle PVP-W₁₈O₄₉@C (PW@C), with significant antioxidant and excellent biocompatibility, was constructed to overcome the limitations of W₁₈O₄₉ in the medical field. Oxygen-deficient W₁₈O₄₉, with irregular defect structure, was combined with hollow carbon nanospheres treated by reflux to obtain W₁₈O₄₉@C (W@C) similar to sea urchins. Compared with W₁₈O₄₉, W@C shows stronger antioxidant properties, and it still has the ability to convert light energy to heat energy after 6 months. In addition, polyvinyl pyrrolidone is coated on the surface of W@C to construct PW@C, which significantly improves biocompatibility of W@C. The photothermal conversion efficiency of PW@C was 42.9 ± 1.3. PWD (PW@C loaded with DOX·HCl) showed controllable drug release behavior under pH and NIR stimulation, and the drug release rate reached 69.1 ± 1.6% at pH = 5.0. Notably, PWD was readily absorbed by cells through clathrin/caveolae-mediated internalization channels, and the viability of HeLa cells treated with PWD + NIR was only 21.5 ± 1.0%. Through photothermal, drug delivery/release and cytotoxicity evaluation, PWD was proved to be an effective platform for chemo-/photothermal combinational tumor therapy.

Impact of macroporous silica nanoparticles at sub-50nm on bio-behaviors and biosafety in drug-resistant cancer models

The in vivo bio-behaviors and biosafety of nanoparticles were demonstrated to be closely correlated with particle sizes, which illustrated whether they could be used as the effective drug delivery carriers. Though tumor penetration capabilities of the small pore sized-mesoporous silica nanoparticles (MSNs) were reported to be in a particle size-dependent manner, the size effects of large pore sized-MSNs on the safe and effective cancer resistance treatment, especially at sub-50 nm, were not explicitly evaluated. In this study, we fabricate the 20 nm and 50 nm MSNs, and aim at investigating their difference in tumor accumulation, penetration, retention and toxicity both in vitro and in vivo. Our results showed that these two particle sized-MSNs possessed the excellent tumor penetration capabilities both in resistant human hepatocellular carcinoma cells-cultured spheroids and in the corresponding xenograft mice models, but the 50 nm MSNs seemed to have the better tumor accumulation and retention effects than the 20 nm MSNs. Moreover, the 50 nm MSNs displayed the lower toxicities than the 20 nm MSNs whatever on resistant cancer cell lines or on zebrafish embryos, indicating the greater systematic biosafety. In a word, our data provide the evidence that selection of the large pore-sized MSNs at the appropriate particle size (not the smaller the better) as bio-macromolecule nanocarriers will play a key role in the safe and effective treatment against cancer resistance.

The reversal of chemotherapy-induced multidrug resistance by nanomedicine for cancer therapy

Multidrug resistance (MDR) of cancer is a persistent problem in chemotherapy. Scientists have considered the overexpressed efflux transporters responsible for MDR and chemotherapy failure. MDR extremely limits the therapeutic effect of chemotherapy in cancer treatment. Many strategies have been applied to solve this problem. Multifunctional nanoparticles may be one of the most promising approaches to reverse MDR of tumor. These nanoparticles can keep stability in the blood circulation and selectively accumulated in the tumor microenvironment (TME) either by passive or active targeting. The stimuli-sensitive or organelle-targeting nanoparticles can release the drug at the targeted-site without exposure to normal tissues. In order to better understand reversal of MDR, three main strategies are concluded in this review. First strategy is the synergistic effect of chemotherapeutic drugs and ABC transporter inhibitors. Through directly inhibiting overexpressed ABC transporters, chemotherapeutic drugs can enter into resistant cells without being efflux. Second strategy is based on nanoparticles circumventing over-expressed efflux transporters and directly targeting resistance-related organelles. Third approach is the combination of multiple therapy modes overcoming cancer resistance. At last, numerous researches demonstrated cancer stem-like cells (CSCs) had a deep relation with drug resistance. Here, we discuss two different drug delivery approaches of nanomedicine based on CSC therapy.

Synergistic Combination of Sodium Aescinate-Stabilized, Polymer-Free, Twin-Like Nanoparticles to Reverse Paclitaxel Resistance

BACKGROUND

The development of paclitaxel (PTX) resistance seriously restricts its clinical efficacy. An attractive option for combating resistance is inhibiting the expression of P-glycoprotein (P-gp) in tumor cells. We have reported that flavokawain A (FKA) inhibited P-gp protein expression in PTX-resistant A549 (A549/T) cells, indicating that FKA combined with PTX may reverse PTX resistance. However, due to the variable pharmacokinetics of FKA and PTX, the conventional cocktail combination in clinics may cause uncertainty of treatment efficacy in vivo.

MATERIALS AND METHODS

To synergistically elevate the anti-cancer activity of PTX and FKA in vivo, the national medical products administration (NMPA) approved sodium aescinate (Aes) was utilized to stabilize hydrophobic PTX and FKA to form polymer-free twin like PTX-A nanoparticles (NPs) and FKA-A NPs.

RESULTS

The resulting nanoparticles prepared simply by nanoprecipitation possessed similar particle size, good stability and ultrahigh drug loadings of up to 50%. With the aid of Aes, these two drugs accumulated in tumor tissue by passive targeting and were efficiently taken up by A549/T cells; this resulted in significant suppression of tumor growth in A549/T homograft mice at a low PTX dose (2.5 mg·kg-1). Synergistic effects and reversed PTX resistance were achieved by the combination of PTX-A NPs and FKA-A NPs by inhibiting P-gp expression in tumor cells.

CONCLUSION

Using NMPA-approved Aes to prepare twin-like nanoparticles without introducing any new materials provides an efficient platform for combination chemotherapy and clinical translation.

Tetrandrine: a review of its anticancer potentials, clinical settings, pharmacokinetics and drug delivery systems

OBJECTIVES

Tetrandrine, a natural bisbenzylisoquinoline alkaloid, possesses promising anticancer activities on diverse tumours. This review provides systematically organized information on cancers of tetrandrine in vivo and in vitro, discuss the related molecular mechanisms and put forward some new insights for the future investigations.

KEY FINDINGS

Anticancer activities of tetrandrine have been reported comprehensively, including lung cancer, colon cancer, bladder cancer, prostate cancer, ovarian cancer, gastric cancer, breast cancer, pancreatic cancer, cervical cancer and liver cancer. The potential molecular mechanisms corresponding to the anticancer activities of tetrandrine might be related to induce cancer cell apoptosis, autophagy and cell cycle arrest, inhibit cell proliferation, migration and invasion, ameliorate metastasis and suppress tumour cell growth. Pharmaceutical applications of tetrandrine combined with nanoparticle delivery system including liposomes, microspheres and nanoparticles with better therapeutic efficiency have been designed and applied encapsulate tetrandrine to enhance its stability and efficacy in cancer treatment.

SUMMARY

Tetrandrine was proven to have definite antitumour activities. However, the safety, bioavailability and pharmacokinetic parameter studies on tetrandrine are very limited in animal models, especially in clinical settings. Our present review on anticancer potentials of tetrandrine would be necessary and highly beneficial for providing guidelines and directions for further research of tetrandrine.

Co-delivery of doxorubicin and oleanolic acid by triple-sensitive nanocomposite based on chitosan for effective promoting tumor apoptosis

Nanocomposites as "stevedores" for co-delivery of multidrugs hold great promise in addressing the drawbacks of traditional cancer chemotherapy. In this work, our strategy presents a new avenue for the stepwise release of two co-delivered agents into the tumor cells. The hybrid nanocomposite consists of a pH-responsive chitosan (CS), a thermosensitive poly(N-vinylcaprolactam) (PNVCL) and a functionalized cell-penetrating peptide (H6R6). Doxorubicin (DOX) and oleanolic acid (OA) are loaded into the nanocomposite (H6R6-CS-g-PNVCL). The system displayed a suitable size (∼190 nm), a high DOX loading (13.2 %) and OA loading efficiency (7.3 %). The tumor microenvironment triggered the nanocomposite to be selectively retained in tumor cells, then releasing the drugs. Both in vitro and in vivo studies showed a significant enhancement in antitumor activity of the co-delivered system in comparison to mono-delivery. This approach which relies on redox, pH and temperature effects utilizing co-delivery nanosystems may be beneficial for future applications in cancer chemotherapy.

pH/redox sequentially responsive nanoparticles with size shrinkage properties achieve deep tumor penetration and reversal of multidrug resistance

pH/redox sequentially responsive nanoparticles with size shrinkage properties achieve deep tumor penetration and reversal of multidrug resistance.

Auto-fluorescent polymer nanotheranostics for self-monitoring of cancer therapy via triple-collaborative strategy

Aberrant regulation of angiogenesis supply sufficient oxygen and nutrients to exacerbate tumor progression and metastasis. Taking this hallmark of cancer into account, reported here is a self-monitoring and triple-collaborative therapy system by auto-fluorescent polymer nanotheranostics which could be concurrently against angiogenesis and tumor cell growth by combining the benefits of anti-angiogenesis, RNA interfere and photothermal therapy (PTT). Auto-fluorescent amphiphilic polymer polyethyleneimine-polylactide (PEI-PLA) with positive charge can simultaneously load hydrophobic antiangiogenesis agent combretastatin A4 (CA4), NIR dye IR825 and absorb negatively charged heat shock protein 70 (HSP70) inhibitor (siRNA against HSP70) to construct self-monitoring nanotheranostics (NPICS). NPICS can effectively restrain the expression of HSP70 to reduce their endurance to the IR825-mediated PTT, leading to an enhanced photocytotoxicity. In a xenograft mouse tumor model, NPICS show an effect of inhibition of tumor angiogenesis and also display a highly synergistic anticancer efficacy with NIR laser irradiation. Significantly, based on its inherent auto-fluorescence, PEI-PLA not only serves as the drug carrier, but also as the self-monitor to real-time track NPICS biodistribution and tumor accumulation via fluorescence imaging. Moreover, IR825 endows NPICS could also be used as photoacoustic (PA) agents for in vivo PA imaging. This nanoplatform shows enormous potentials in cancer theranostics.

Glutathione detonated and pH responsive nano-clusters of Au nanorods with a high dose of DOX for treatment of multidrug resistant cancer

Effects of nanosized drug delivery systems on cancer are often compromised due to their low drug loadings, premature drug release and multi-drug resistance (MDR). Herein, we reported a glutathione detonated and pH responsive nano-cluster of Au nanorods (AuNRs) with chemotherapeutic doxorubicin (DOX) and pre-chemosensitizer polycurcumin to treat MCF-7/ADR cells. The nano-cluster was prepared by self-assembling of AuNRs conjugated with DOX and amphiphilic poly(curcumin-co-dithiodipropionic acid)-b-biotinylated poly(ethylene glycol) via an emulsion/solvent evaporation technique, termed AuNR Cluster. The AuNR Cluster had a high drug loading (31.5% DOX), presenting much better aqueous solubility and stability at physiological pH than their individual AuNRs. The AuNR Cluster could be detonated to be their individual AuNRs at an intracellular concentration level of glutathione (GSH) (5 mM) and triggered to release DOX at an acidic pH (pH 6.8 or 5.0), which effectively facilitated cellular uptake of DOX (607 vs 356 a.u. for AuNRs at 12 h) and inhibited DOX efflux (471.33 vs 39.17 a.u. for free DOX at 24 h). The IC₅₀ value of DOX against MCF-7/ADR cells for AuNR Cluster was 4.15 µg/mL, much lower than that for free DOX (90.97 µg/mL). The AuNR Cluster took much more photothermal effects than their corresponding AuNRs and presented enhanced anti-tumor effect (IC₅₀: 2.61 µg/mL) under 808 nm laser irradiation.

STATEMENT OF SIGNIFICANCE

Nano-sized drug delivery systems for anti-MDR cancer is still a challenging task. Herein, AuNR Cluster was self-assembled by individual AuNRs via emulsion/solvent evaporation technique, having a structure consisting of hydrophobic DOX/PCDA-AuNR core and hydrophilic biotin-PEG chain shell. AuNR Cluster is detonated to disintegrate and yield its individual AuNRs at an intracellular concentration level of glutathione (5 mM) and triggered to release DOX at an acidic pH (6.8 or 5.0). In comparison with its individual AuNRs, AuNR Cluster has better water solubility and stability, greater photothermal effects under NIR irradiation, bigger cytotoxicity against MCF-7/ADR cells. AuNR Cluster is expected to be a potential nanomedicine for treatment of MDR cancer.

Triple Stimuli-Responsive Magnetic Hollow Porous Carbon-Based Nanodrug Delivery System for Magnetic Resonance Imaging-Guided Synergistic Photothermal/Chemotherapy of Cancer

The premature leakage of anticancer drugs during blood circulation may the damage immune system, normal cells, and tissues. Constructing targeted nanocarriers with pH, glutathione, and NIR triple-responsive property can effectively avoid the leakage of anticancer drugs before they arrive at the targeted site. In this paper, magnetic hollow porous carbon nanoparticles (MHPCNs) were successfully fabricated as nanocarrier. Poly(γ-glutamic acid) was used to cap the pores of MHPCNs. The photothermal conversion property of carbon and iron oxide (Fe₃O₄) nanomaterials was utilized to perform photothermal therapy to overcome multidrug-resistance produced by chemotherapy. The biodistribution of nanoparticles was investigated by magnetic resonance imaging. Experiments in vivo confirm the efficient accumulations of nanoparticles at tumor sites. Meanwhile, tumor growth was effectively inhibited via synergistic photothermal/chemotherapy with minimal side effects.

Unified D-α-Tocopherol 5-Fu/SAHA bioconjugates self-assemble as complex nanodrug for optimized combination therapy

Aim: To optimize the synergistic efficacy of combination therapy with controlled molar ratio, complex small molecule-based nanodrug (Co-SMND) of 5-fluorouracil (5-Fu)/vorinostat (SAHA) was developed. Materials & methods: Co-SMND with various ratios of 5-Fu-D-α-tocopherol (VE)/SAHA-VE were prepared and characterized including co-assembly mechanism, hydrolytic stability, cytotoxicity, synergistic effect and apoptosis inducing ability. The antitumor activity, systematic toxicity and biodistribution of optimized Co-SMND were evaluated in CT-26 bearing BALB/c mouse. Results: Maximal synergistic effect of Co-SMND could be obtained via simply adjusting the feeding molar ratio. The optimized Co-SMND showed superior in vivo antitumor efficacy, upregulated security and selective intratumoral accumulation. Conclusion: Such Co-SMND is of great significance for future clinical translation, and would be an efficient platform for combination chemotherapy.

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.

Photosensitive Nanoparticles Combining Vascular-Independent Intratumor Distribution and On-Demand Oxygen-Depot Delivery for Enhanced Cancer Photodynamic Therapy

In drug delivery, the poor tumor perfusion results in disappointing therapeutic efficacy. Nanomedicines for photodynamic therapy (PDT) greatly need deep tumor penetration due to short lifespan and weak diffusion of the cytotoxic reactive oxygen species (ROS). The damage of only shallow cells can easily cause invasiveness and metastasis. Moreover, even if the nanomedicines enter into deeper lesion, the effectiveness of PDT is limited due to the hypoxic microenvironment. Here, a deep penetrating and oxygen self-sufficient PDT nanoparticle is developed for balanced ROS distribution within tumor and efficient cancer therapy. The designed nanoparticles (CNPs/IP) are doubly emulsified (W/O/W) from poly(ethylene glycol)-poly(ε-caprolactone) copolymers doped with photosensitizer IR780 in the O layer and oxygen depot perfluorooctyl bromide (PFOB) inside the core, and functionalized with the tumor penetrating peptide Cys-Arg-Gly-Asp-Lys (CRGDK). The CRGDK modification significantly improves penetration depth of CNPs/IP and makes the CNPs/IP arrive at both the periphery and hypoxic interior of tumors where the PFOB releases oxygen, effectively alleviating hypoxia and guaranteeing efficient PDT performance. The improved intratumoral distribution of photosensitizer and adequate oxygen supply augment the sensitivity of tumor cells to PDT and significantly improve PDT efficiency. Such a nanosystem provides a potential platform for improved therapeutic index in anticancer therapy.

Programmed drug delivery system based on optimized "size decrease and hydrophilicity/hydrophobicity transformation" for enhanced hepatocellular carcinoma therapy of doxorubicin

Requirements on drug delivery systems to surmount a complex series of pathophysiological barriers bear "cascading contradictions", especially size and hydrophilicity/hydrophobicity contradiction. Herein, a programmed drug delivery system (GNPs-Dox-Lac) based on optimized "size decrease and hydrophilicity/hydrophobicity transformation" was developed by combination the gelatin nanoparticle (GNPs) and prodrug Doxorubicin-Lactose (Dox-Lac). The results showed that GNPs-Dox-Lac (133.3 nm) were kinetically stable in blood circulation and inclined to accumulate at the tumor site. Then the degradation of the GNPs triggered by tumor extracellular matrix metalloproteinase-2 (MMP2) led to the release of prodrug Dox-Lac (Mw 898 Da) to facilitate the tumor tissue penetration and cellular uptake. Last, pH-responsive disassociation of Dox-Lac in tumor cells resulted in the free Dox (Mw 543 Da) release to induce toxicity. As expected, GNPs-Dox-Lac achieved superior tumor inhibition rate of 90.8% with low toxicity in vivo, suggesting its potential for enhanced hepatocellular carcinoma (HCC) therapy of doxorubicin in future.