Growth of MCF-7 breast cancer cells and efficacy of anti-angiogenic agents in a hydroxyethyl chitosan/glycidyl methacrylate hydrogel.

BACKGROUND: Breast cancer negatively affects women's health worldwide. The tumour microenvironment plays a critical role in tumour initiation, proliferation, and metastasis. Cancer cells are traditionally grown in two-dimensional (2D) cultures as monolayers on a flat solid surface lacking cell-cell and cell-matrix interactions. These experimental conditions deviate from the clinical situation. Improved experimental systems that can mimic the in vivo situation are required to discover new therapies, particularly for anti-angiogenic agents that mainly target intercellular factors and play an essential role in treating some cancers. METHODS: Chitosan can be modified to construct three-dimensional (3D) tumour models. Here, we report an in vitro 3D tumour model using a hydroxyethyl chitosan/glycidyl methacrylate (HECS-GMA) hydrogel produced by a series of chitosan modifications. Parameters relating to cell morphology, viability, proliferation, and migration were analysed using breast cancer MCF-7 cells. In a xenograft model, secretion of angiogenesis-related growth factors and the anti-angiogenic efficacy of Endostar and Bevacizumab in cells grown in HECS-GMA hydrogels were assessed by immunohistochemistry. RESULTS: Hydroxyethyl chitosan/glycidyl methacrylate hydrogels had a highly porous microstructure, mechanical properties, swelling ratio, and morphology consistent with a 3D tumour model. Compared with a 2D monolayer culture, breast cancer MCF-7 cells residing in the HECS-GMA hydrogels grew as tumour-like clusters in a 3D formation. In a xenograft model, MCF-7 cells cultured in the HECS-GMA hydrogels had increased secretion of angiogenesis-related growth factors. Recombinant human endostatin (Endostar), but not Bevacizumab (Avastin), was an effective anti-angiogenic agent in HECS-GMA hydrogels. CONCLUSIONS: The HECS-GMA hydrogel provided a 3D tumour model that mimicked the in vivo cancer microenvironment and supported the growth of MCF7 cells better than traditional tissue culture plates. The HECS-GMA hydrogel may offer an improved platform to minimize the gap between traditional tissue culture plates and clinical applicability. In addition, the anti-angiogenic efficacy of drugs such as Endostar and Bevacizumab can be more comprehensively studied and assessed in HECS-GMA hydrogels.

Hyaluronan-decorated copper-doxorubicin-anlotinib nanoconjugate for targeted synergistic chemo/chemodynamic/antiangiogenic tritherapy against hepatocellular carcinoma.

Copper-based nanomaterials show considerable potential in the chemodynamic therapy of cancers. However, their clinical application is restricted by low catalytic activity in tumor microenvironment and copper-induced tumor angiogenesis. Herein, a novel copper-doxorubicin-anlotinib (CDA) nanoconjugate was constructed by the combination of copper-hydrazide coordination, hydrazone linkage and Schiff base bond. The CDA nanoconjugate consists of a copper-3,3'-dithiobis(propionohydrazide)-doxorubicin core and an anlotinib-hyaluronan shell. Benefiting from hyaluronan camouflage and abundant disulfide bonds and Cu2+, the CDA nanoconjugate possessed excellent tumor-targeting and glutathione-depleting abilities and enhanced chemodynamic efficacy. Released doxorubicin significantly improved copper-mediated chemodynamic therapy by upregulating nicotinamide adenine dinucleotide phosphate oxidase 4 expression to increase intracellular H2O2 level. Furthermore, the nanoconjugate produced excessive •OH to induce lipid peroxidation and mitochondrial dysfunction, thus greatly elevating doxorubicin-mediated chemotherapy. Importantly, anlotinib effectively inhibited the angiogenic potential of copper ions. In a word, the CDA nanoconjugate is successfully constructed by combined coordination and pH-responsive linkages, and displays the great potential of copper-drug conjugate for targeted synergistic chemo/chemodynamic/antiangiogenic triple therapy against cancers.

Tumor Microenvironment Responsive Hollow Nanoplatform for Triple Amplification of Oxidative Stress to Enhance Cuproptosis-Based Synergistic Cancer Therapy.

Cuproptosis is a recently discovered form of programmed cell death and shows great potential in cancer treatment. Herein, a copper-dithiocarbamate chelate-doped and artemisinin-loaded hollow nanoplatform (HNP) is developed via a chelation competition-induced hollowing strategy for cuproptosis-based combination therapy. The HNP exhibits tumor microenvironment-triggered catalytic activity, wherein liberated Cu2+ catalyzes artemisinin and endogenous H2 O2 to produce C-centered radicals and hydroxyl radicals, respectively. Meanwhile, the disulfide bonds-rich HNP can deplete intracellular glutathione, thus triply amplifying tumor oxidative stress. The augmented oxidative stress sensitizes cancer cells to the cuproptosis, causing prominent dihydrolipoamide S-acetyltransferase oligomerization and mitochondrial dysfunction. Moreover, the HNP can activate ferroptosis via inhibiting GPX4 activity and trigger apoptosis via dithiocarbamate-copper chelate-mediated ubiquitinated proteins accumulation, resulting in potent antitumor efficacy. Such a cuproptosis/ferroptosis/apoptosis synergetic strategy opens a new avenue for cancer therapy.

Hydrazide/Metal/Indocyanine Green Coordinated Nanoplatform for Potentiating Reciprocal Ferroptosis and Immunity against Melanoma.

Ferroptosis holds great potential in cancer treatment, but its efficacy is severely limited by a low Fenton reaction efficacy. Meanwhile, the interactive relationship between Ferroptosis and the PD-1 blockade is still vague. Herein, a hydrazide/Cu/Fe/indocyanine green coordinated nanoplatform (TCFI) is constructed by a hydrazide-metal-sulfonate coordination process. The TCFI nanoplatform exhibits Fenton-/catalase-/glutathione oxidase-like triple activities and accordingly can trigger lipid peroxidation, relieve hypoxia, and downregulate the glutathione/glutathione peroxidase 4 axis, thus achieving positively and negatively dually enhanced Ferroptosis in B16F10 cancer cells. Under near-infrared laser irradiation, the TCFI nanoplatform induces robust immunogenic cancer cell death by elevating the intracellular reactive oxygen species level through synergistic photodynamic therapy/Ferroptosis, which significantly potentiates CD8+ T cell infiltration into tumors and interferon-γ secretion. Moreover, upregulated interferon-γ efficiently inhibits system xc- activity and sensitizes cancer cells to Ferroptosis. Interestingly, the PD-1 blockade may strengthen the reciprocal process. The combination of the TCFI nanoplatform and αPD-1 can eliminate primary tumors and inhibit distant tumor growth, lung metastasis, and tumor recurrence. This study presents a simple and novel coordination strategy to fabricate tumor microenvironment-responsive nanodrugs and highlights the enhancement effect of photodynamic therapy on reciprocal Ferroptosis and antitumor immunity.

Copper-Hydrazide Coordinated Multifunctional Hyaluronan Hydrogels for Infected Wound Healing.

Bacterial infection and delayed healing are two major obstacles in cutaneous wound management, and developing multifunctional hydrogels with antibacterial and prohealing capabilities presents a promising strategy to dress wounds. However, the simple and facile fabrication of such hydrogel dressings remains challenging. Herein, we report the first observation on hydrazide-metal coordination crosslinking that is utilized to successfully construct a series of hyaluronan (HA)-metal hydrogels by mixing hydrazided HA and metal ion solutions. Considering the antibacterial, prohealing, and proangiogenic properties of HA and Cu(II), as a proof of principle, a HA-Cu hydrogel was systematically investigated as a wound dressing. Surprisingly, the hydrazide-Cu(II) coordination was dynamic in nature and imparted the HA-Cu hydrogel with physicochemical multifunctions, including spontaneous self-healing, shear-thinning injectability, reversible pH/redox/ion pair triple responsiveness, etc. Moreover, the HA-Cu hydrogel exhibited a robust broad-spectrum antibacterial activity and could significantly accelerate infectious wound healing. Impressively, glutathione-triggered hydroxyl radical generation further potentiated wound healing, providing a paradigm for on-demand antibacterial activity enhancement. Hence, the HA-Cu hydrogel is a clinically applicable "smart" dressing for multi-scenario wound healing. We envision that the simple and versatile coordination approach opens up a new avenue to develop multifunctional hydrogels and shows great potential in frontier fields, such as biomedicine, wearable devices, and soft robots.

Photo-crosslinked hyaluronic acid hydrogel as a biomimic extracellular matrix to recapitulate in vivo features of breast cancer cells.

2D cell culture is widely utilized to develop anti-cancer drugs and to explore the mechanisms of cancer tumorigenesis and development. However, the findings obtained from 2D culture often fail to provide guidance for clinical tumor treatments since it cannot precisely replicate the features of real tumors. 3D tumor models capable of recapitulating native tumor microenvironments have been proved to be a promising alternative technique. Herein, we constructed a breast tumor model from novel hyaluronic acid (HA) hydrogel which was prepared through photocrosslinking of methacrylated HA. The hydrogel was used as a biomimetic extracellular matrix to incubate MCF-7 cells. It was found that methacrylation degree had great effects on hydrogel's microstructure, mechanical performances, and liquid-absorbing and degradation abilities. Optimized hydrogel exhibited highly porous morphology, high equilibrium swelling ratio, suitable mechanical properties, and hyaluronidase-responsive degradation behavior. The results demonstrated that the HA hydrogel facilitated MCF-7 cell proliferation and growth in an aggregation manner. Furthermore, 3D-cultured MCF-7 cells not only up-regulated the expression of VEGF, bFGF and interleukin-8 but exhibited greater invasion and tumorigenesis capabilities compared with 2D-cultured cells. Therefore, the HA hydrogel is a reliable substitute for tumor model construction.

Hydrazided hyaluronan/cisplatin/indocyanine green coordination nanoprodrug for photodynamic chemotherapy in liver cancer.

It is still a huge challenge for concurrent highly efficient loading of chemotherapeutic agent and photosensitizer into single nanocarrier via stimuli-responsive linkages due to their different physicochemical properties and pharmacokinetics. Herein, based on the discovery of unique cisplatin-hydrazide and cisplatin-indocyanine green (ICG) coordination reactions, a multifunctional coordination nanoprodrug, cisplatin/ICG co-loaded hydrazided hyaluronan/bovine serum albumin (HBCI) nanoparticles, was developed by a desolvation-dual coordination process. The nanoprodrug exhibited ultrahigh drug loading efficiency and glutathione/NIR light dual-responsive drug release behavior. In vitro cellular studies demonstrated efficient internalization and apoptosis-inducing ability of the nanoprodrug in HepG2 cells. In vivo results confirmed the efficacious tumor accumulation and biosafety of HBCI nanoprodrug and synergistic effect of HBCI-based combined photodynamic chemotherapy on inhibiting tumor growth. Overall, this work not only provides a novel dual coordination approach for highly efficient loading of cisplatin and ICG but also verifies the therapeutic potential of HBCI nanoprodrug in combating hepatocellular carcinoma.

Injectable hyaluronan/MnO2 nanocomposite hydrogel constructed by metal-hydrazide coordinated crosslink mineralization for relieving tumor hypoxia and combined phototherapy.

Hydrogel-based drug delivery holds great promise in topical tumor treatment. However, the simple construction of multifunctional therapeutic hydrogels under physiological conditions is still a huge challenge. Herein, for the first time, a multifunctional hyaluronan/MnO2 nanocomposite (HHM) hydrogel with injectable and self-healing capabilities was constructed under physiological conditions through innovative in situ mineralization-triggered Mn-hydrazide coordination crosslinking. The hydrogel formed from Mn2+ and hydrazided hyaluronan under optimized conditions exhibited a high elastic modulus >1 kPa, injectability, self-healing function, stimuli-responsiveness and catalase-like activity. In vitro and in vivo biological experiments demonstrated that our HHM hydrogel could not only efficiently relieve hypoxia by in situ catalytic decomposition of endogenous H2O2 into O2 but also achieve synergistic photodynamic/photothermal therapy of 4T1 breast cancer in a mouse tumor model. This study presented a novel mineralization-driven metal-hydrazide coordination crosslinking approach and developed a multifunctional therapeutic platform for O2-enhanced efficient topical dual-phototherapy of breast cancer.

Hydrazide-manganese coordinated multifunctional nanoplatform for potentiating immunotherapy in hepatocellular carcinoma.

Immune checkpoint blockade (ICB)-based immunotherapy is a revolutionary therapeutic strategy for hepatocellular carcinoma (HCC). However, tumor immune tolerance and escape severely restrict the therapeutic efficacy of ICB therapy. It is urgent to explore new strategies to potentiate ICB therapy in HCC. Herein, we developed manganese oxide-crosslinked bovine albumin/hyaluronic acid nanoparticles (BHM) by an innovative hydrazide-manganese coordination and desolvation process. Successive loading of doxorubicin (DOX) and indocyanine green (ICG) was achieved via hydrazone linkage and electrostatic interactions, respectively, obtaining DOX/ICG-coloaded BHM nanoplatform (abbreviated as BHMDI). The BHMDI nanoplatform exhibited a high drug content (>46%) and pH/reduction dual-responsive drug release behavior. The nanoplatform could efficiently alleviate tumor hypoxia by catalytic decomposition of intracellular H2O2 to O2 and significantly improve BHMDI-based photodynamic chemotherapy efficacy. The BHMDI nanoplatform downregulated the proportion of alternatively activated (M2) macrophages in tumors and simultaneously induced immunogenic death of HCC cells, thus promoting the maturation of dendritic cells and ensuing priming of CD4+ and CD8+ T cells. Importantly, programmed death-1 (PD-1) blockade in combination with BHMDI nanoplatform not only eradicated primary tumors but inhibited tumor recurrence, abscopal tumor growth and lung metastasis of HCC by triggering robust systemic antitumor immunity. This work proved the feasibility of BHMDI-based photodynamic chemotherapy for potentiating PD-1 blockade immunotherapy by reversing hypoxic and immunosuppressive tumor microenvironment.

Hydroxyethyl chitosan hydrogels for enhancing breast cancer cell tumorigenesis.

Polysaccharide hydrogels are promising candidate matrices for recapitulating the characteristics of extracellular matrix (ECM) in breast tumors in terms of their structure and composition. Herein, to obtain an ECM-mimetic matrix, hydroxyethyl chitosan (HECS) hydrogels were prepared through Schiff-base crosslinking reaction using dialdehyde hyaluronic acid as crosslinker. The obtained HECS hydrogels displayed a highly porous structure, a stiffness comparable to that of breast tissue, and a fast water-absorption speed. The amount of crosslinker had great effects on the swelling and rheological behaviors of the HECS hydrogels. Preliminary results from in vitro biological assessments confirmed that MCF-7 cells incubated within HECS hydrogels preferred to grow into three-dimensional spheroids. Importantly, the cells displayed enhanced migrative capability and upregulated expression levels of MMP-2, TGF-ß and VEGF in comparison to two-dimension cultured cells. Hence, the HECS hydrogels show great promise as a biomimetic ECM in constructing breast tumor models.

Pure polylysine-based foamy scaffolds and their interaction with MC3T3-E1 cells and osteogenesis.

Polypeptide-derived copolymers have widely been exploited for drug/gene delivery due to their pendant functional groups and non-toxic degradation products. However, fabrication of polypeptide-based scaffolds for tissue engineering has seldom been reported. In this study, foamy poly(N ε -benzyl formateoxycarbonyl-L-Lysine) (PZL) and poly(N ε -benzyl formateoxycarbonyl-L-lysine-co-L-phenylalanine) (PZLP) scaffolds were successfully prepared by a combination of ring-opening polymerization of α-amino acid N-carboxyanhydride and negative porous NaCl templating approach. The physicochemical properties of these scaffolds including glass transition temperature, contact angle, compression modulus and degradation behavior were characterized. Both in vitro and in vivo biocompatibility of the scaffolds were evaluated by MC3T3-E1 cell culture and SD subcutaneous model, respectively. The results from live-dead staining, MTT and ALP activity assays indicated that PZL scaffolds were more conducive to the adhesion, proliferation and osteoblastic differentiation of MC3T3-E1 cells compared to PZLP scaffolds in the initial culture period due to their specific surface properties. While porous structure rather than surface properties of scaffolds played a decisive role in the later stage of cell culture. The results of in vivo studies including H&E, Masson's trichrome and CD34 staining further demonstrated that PZL scaffolds supported the ingrowth of microvessels than PZLP scaffolds due to their surface property difference. Collectively, PZL scaffolds displayed good biocompatibility and could be a promising candidate for tissue engineering application.

Multiwall carbon nanotube and TiO2 sol assembly.

Carbon nanotube and TiO2 assemblies (CNT/TiO2) have the great promise of combining the advantages of CNTs and TiO2 as photocatalytic and energy conversion materials. In this study, nanoscale TiO2 sol was assembled onto multiwall carbon nanotubes (MWCNTs). The CNT/TiO2 sol assemblies were characterized by transmission electron microscopy, energy dispersive spectroscopy, and Fourier transform infrared spectroscopy. The study shows that the acidic functional group concentration on CNT surfaces increases with surface modification temperature, up to 1.179 mmol/g. Higher concentration of acidic functional group greatly improves the amount of TiO2 sol assembled onto MWCNTs. Higher TiO2 sol concentration also improves the amount of TiO2 sol assembled onto MWCNT surfaces. The assembly mechanism is mainly by chemical reaction between the -COOH groups of MWCNTs and the -OH groups of TiO2 sol by esterification.

NIR/pH dual-responsive polysaccharide-encapsulated gold nanorods for enhanced chemo-photothermal therapy of breast cancer.

Combination of different therapy modalities with multiple tumoricidal mechanisms has emerged as a promising anticancer strategy. Herein, we reported an aldehyde/catechol-functionalized hyaluronic acid (DAHA) and hydroxyethyl chitosan (HECS) decorated gold nanorod (GNR) platform for combined chemo-photothermal therapy of breast cancer. The DAHA was synthesized by conjugating dopamine onto oxidized hyaluronic acid. The nanoplatform was prepared by successively modifying GNR with DAHA via Au-catechol bonds, conjugating DOX onto DAHA moiety through Schiff base linkage, and coating HECS interlayer for charge-reversal and hyaluronic acid corona for tumor cell targeting. The resulting nanoplatform GNR-HADOXCH exhibited acid-triggered surface charge-reversal and pH/NIR dual-responsive drug release behaviors. The nanoplatform could be efficiently internalized into MCF-7 breast cancer cells and displayed greater cancer cell killing than individual modalities. Therefore, polysaccharide decoration could ensure the co-delivery of GNR and DOX into cancer cells, and the developed GNR-HADOXCH holds great potential for breast cancer treatment.

Dual-degradable and injectable hyaluronic acid hydrogel mimicking extracellular matrix for 3D culture of breast cancer MCF-7 cells.

In tumor biology, it is widely recognized that 3D rather than 2D cell culture can recapitulate key features of solid tumors, including cell-extracellular matrix (ECM) interactions. In this study, to mimick the ECM of breast cancer, hyaluronic acid (HA) hydrogels were synthesized from two polyvalent HA derivatives through a hydrazone and photo dual crosslinking process. HA hydrogels could be formed within 120 s. The hydrogels had similar topography and mechanical properties to breast tumor and displayed glutathione and hyaluronidase dual-responsive degradation behavior. Biological studies demonstrated that HA hydrogel could support the proliferation and clustering of breast cancer MCF-7 cells. The expression levels of VEGF, IL-8 and bFGF in hydrogel-cultured cells were significantly greater than those in 2D culture. Moreover, cells from hydrogel culture exhibited greater migration/invasion abilities and tumorigenicity than 2D-cultured cells. Therefore, the HA hydrogels are a promising ECM-mimicking matrix for in vitro construction of breast cancer.

Multifunctional PEG-b-polypeptide-decorated gold nanorod for targeted combined chemo-photothermal therapy of breast cancer.

The combination of chemotherapy and photothermal therapy is acknowledged as one of the most promising approaches in cancer treatment. Targeted delivery and controlled drug release are two important factors for combined chemo-photothermal therapy. In this study, a multifunctional nanoplatform based on gold nanorod (GNR) decorated with folate-conjugated poly(ethylene glycol)-b-poly(L-γ-glutamylhydrazine) (FEGGH) containing disulfide linker and dihydroxyphenyl groups was developed for targeted combined chemo-photothermal therapy of breast cancer. FEGGH was synthesized by ring-opening polymerization of γ-benzyl-l-glutamate-N-carboxyanhydride using folate/cystamine-heterobifunctionalized poly(ethylene glycol) as an initiator, following by hydrazinolysis and carbodiimide reactions. FEGGH was decorated onto GNR through Au-catechol bonds. Chemotherapeutic drug doxorubicin (DOX) was loaded onto the nanoplatform through pH-sensitive hydrazone linkage, obtaining final product FEGGHDOX-GNR. The DOX-loaded nanoplatform displayed excellent photostability and reduction/pH dual-responsive drug release behavior. Cytological studies demonstrated the effective internalization of FEGGHDOX-GNR into MCF-7 cells via folate-mediated endocytosis and additive therapeutic effect of combined photothermal-chemotherapy. These results indicate that our nanoplatform may be a promising strategy for targeted combined chemo-photothermal therapy of breast cancer.

Doxorubicin/cisplatin co-loaded hyaluronic acid/chitosan-based nanoparticles for in vitro synergistic combination chemotherapy of breast cancer.

Combination chemotherapy has attracted more and more attention in the field of anticancer treatment. Herein, a synergetic targeted combination chemotherapy of doxorubicin (DOX) and cisplatin in breast cancer was realized by HER2 antibody-decorated nanoparticles assembled from aldehyde hyaluronic acid (AHA) and hydroxyethyl chitosan (HECS). Cisplatin and DOX were successively conjugated onto AHA through chelation and Schiff's base reaction, respectively, forming DOX/cisplatin-loaded AHA inner core. The core was sequentially complexed with HECS and targeting HER2 antibody-conjugated AHA. The formed near-spherical nanoplatform had an average size of ∼160 nm and a zeta potential of -28 mV and displayed pH-responsive surface charge reversal and drug release behaviors. HER2 receptor-mediated active targeting significantly enhanced the cellular uptake of nanoplatform. Importantly, DOX and cisplatin exhibited a synergistic cell-killing effect in human breast cancer MCF-7 cells. These results clearly indicate that the novel nanoplatform is promising for synergistic combination chemotherapy of breast cancer.

Sequentially self-assembled polysaccharide-based nanocomplexes for combined chemotherapy and photodynamic therapy of breast cancer.

Combination of chemotherapy and photodynamic therapy has emerged as a promising anticancer strategy. Polysaccharide-based nanoparticles are being intensively explored as drug carriers for different forms of combination therapy. In this study, novel multifunctional polysaccharide-based nanocomplexes were prepared from aldehyde-functionalized hyaluronic acid and hydroxyethyl chitosan via sequential self-assembly method. Stable nanocomplexes were obtained through both Schiff's base bond and electrostatic interactions. Chemotherapeutics doxorubicin and pro-photosensitizer 5-aminolevulinic acid were chemically conjugated onto the nanocomplexes via Schiff base linkage. Anti-HER2 antibody as targeting moiety was decorated onto the surface of nanocomplexes. The obtained near-spherical shaped nanocomplexes had an average size of 140 nm and a zeta potential of -24.6 mV, and displayed pH-responsive surface charge reversal and drug release. Active targeting strategy significantly enhanced the cellular uptake of nanocomplexes and combined anticancer efficiency of chemo-photodynamic dual therapy in breast cancer MCF-7 cells. These results suggested that the nanocomplexes had great potential for targeted combination therapy of breast cancer.

A dual-targeted hyaluronic acid-gold nanorod platform with triple-stimuli responsiveness for photodynamic/photothermal therapy of breast cancer.

Multi-stimuli-responsive theranostic nanoplatform integrating functions of both imaging and multimodal therapeutics holds great promise for improving diagnosis and therapeutic efficacy. In this study, we reported a pH, glutathione (GSH) and hyaluronidase (HAase) triple-responsive nanoplatform for HER2 and CD44 dual-targeted and fluorescence imaging-guided PDT/PTT dual-therapy against HER2-overexpressed breast cancer. The nanoplatform was fabricated by functionalizing gold nanorods (GNRs) with hyaluronic acid (HA) bearing pendant hydrazide and thiol groups via Au-S bonds, and subsequently chemically conjugating 5-aminolevulinic acid (ALA), Cy7.5 and anti-HER2 antibody onto HA moiety for PDT, fluorescence imaging and active targeting, respectively. The resulting versatile nanoplatform GNR-HA-ALA/Cy7.5-HER2 had uniform sizes, favorable dispersibility, as well as pH, GSH and HAase triple-responsive drug release manner. In vitro studies demonstrated that HER2 and CD44 receptor-mediated dual-targeting strategy could significantly enhance the cellular uptake of GNR-HA-ALA/Cy7.5-HER2. Under near-infrared (NIR) irradiation, MCF-7 cells could efficiently generate reactive oxygen species (ROS) and heat, and be more efficiently killed by a combination of PDT and PTT as compared with individual therapy. Pharmacokinetic and biodistribution studies showed that the nanoplatform possessed a circulation half-life of 1.9 h and could be specifically delivered to tumor tissues with an accumulation ratio of 12.8%. Upon the fluorescence imaging-guided PDT/PTT treatments, the tumors were completely eliminated without obvious side effects. The results suggest that the GNR-HA-ALA/Cy7.5-HER2 holds great potential for breast cancer therapy. STATEMENT OF SIGNIFICANCE: A combination of photodynamic therapy (PDT) and photothermal therapy (PTT) is emerging as a promising cancer treatment strategy. However, its therapeutic efficacy is compromised by the nonspecific delivery and unintended release of photo-responsive agents. Herein, we developed a multifunctional theranostic nanoplatform GNR-HA-ALA/Cy7.5-HER2 with pH, glutathione and hyaluronidase triple-responsive drug release for HER2 and CD44 dual-targeted and fluorescence imaging-guided PDT/PTT therapy against breast cancer. We demonstrated that HER2 and CD44 receptors-mediated dual-targeting strategy significantly enhanced the cellular uptake of GNR-HA-ALA/Cy7.5-HER2. We also demonstrated that the combined PDT/PTT treatment had significantly superior antitumor effect than PDT or PTT alone both in vitro and in vivo. Therefore, GNR-HA-ALA/Cy7.5-HER2 could serve as a promising nanoplatform for HER2-positive breast cancer therapy.

A novel pH-sensitive targeting polysaccharide-gold nanorod conjugate for combined photothermal-chemotherapy of breast cancer.

Chemo-photothermal combination therapy is a promising strategy for cancer treatment. In this study, to achieve the combined photothermal-chemotherapy of breast cancer, a pH-sensitive oxidized hyaluronic acid-decorated dihydroxyphenyl/hydrazide bifunctionalized hydroxyethyl chitosan (DHHC)-gold nanorod (GNR) conjugate was developed. DHHC was synthesized by successive dihydroxyphenylation and hydrazidation of hydroxyethyl chitosan through carbodiimide reaction and click chemistry, respectively. The conjugate was obtained by chemically bonding DHHC onto GNR via Au-catechol bonds. Doxorubicin (DOX) was loaded onto the conjugate via an acid-labile hydrazone linkage with a drug loading content of 5.1%. DOX-loaded conjugate displayed good stability in neutral aqueous solutions and exhibited pH-responsive drug release and surface charge reversal behaviors. In vitro biological studies indicated that the conjugate could be effectively internalized by breast cancer MCF-7 cells and synergistic therapeutic effects were demonstrated, suggesting its great potential in combined photothermal-chemotherapy of breast cancer.

PEGylated hydrazided gold nanorods for pH-triggered chemo/photodynamic/photothermal triple therapy of breast cancer.

Integration of multimodal therapies into one nanoplatform holds great promise to overcome the drawbacks of conventional single-modal therapy and pursues enhanced anticancer efficacy. Herein, we developed a PEGylated gold nanorods (GNRs)-based nanoplatform (GNRs-MPH-ALA/DOX-PEG) with pH-responsive drug release property for triple-combined chemotherapy (CT), photodynamic therapy (PDT) and photothermal therapy (PTT) of breast cancer. GNRs were first decorated with mercaptopropionylhydrazide (MPH) and thiol-terminated monomethoxyl poly(ethylene glycol) (mPEG-SH) via Au-thiol linkage, and subsequently conjugated with chemotherapeutant doxorubicin (DOX) and pro-photosensitizer 5-aminolevulinic acid (ALA) through acid-liable hydrazone bonds between drugs and MPH molecules. The resulting nanoplatform GNRs-MPH-ALA/DOX-PEG exhibited excellent stability in physiological solutions and pH-responsive DOX and ALA release behaviors. In vitro studies showed that GNRs-MPH-ALA/DOX-PEG could efficiently enter human breast cancer MCF-7 cells and release DOX and ALA into cytoplasm. Furthermore, DOX could locate in the cell nucleus and ALA was productively metabolized into protoporphyrin IX (PpIX). Upon near-infrared (NIR) irradiation, PpIX produced enough reactive oxygen species for PDT and meanwhile GNRs could efficiently induce hyperthermia for PTT. Compared with single CT and dual-modal CT/PDT or CT/PTT treatment, the triple-combined CT/PDT/PTT treatment could more efficiently kill MCF-7 cells via a superadditive antitumor effect. Furthermore, the circulation half-life of GNRs-MPH-ALA/DOX-PEG in the blood was as long as approximately 52 min and it exhibited a tumor accumulation of 3.3%. The triple-combined CT/PDT/PTT treatment could completely suppress tumor growth without obvious systemic toxicity. Our study paves a new avenue for multimodal therapy of breast cancer. STATEMENT OF SIGNIFICANCE: The development of a simple but effective strategy to construct a versatile nanoplatform for multi-combined therapy still remains an enormous challenge. In this work, we developed a novel and simple nanoplatform GNRs-MPH-ALA/DOX-PEG with pH-responsive drug release for triple-combined chemotherapy (CT), photodynamic therapy (PDT) and photothermal therapy (PTT) of breast cancer. The nanoplatform could be efficiently internalized by MCF-7 cells. The intracellular GNRs-MPH-ALA/DOX-PEG could release DOX for CT, induce hyperthermia for PTT and generate high levels of ROS for PTT. Compared with single CT and dual-modal CT/PDT or CT/PTT treatments, the triple-combined CT/PDT/PTT treatment could more efficiently kill MCF-7 cells via a superadditive antitumor effect. Furthermore, upon triple-combined CT/PDT/PTT treatment, the tumor growth was completely suppressed without obvious systemic toxicity.