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Clinically, cancer drug resistance to chemotherapy, targeted therapy or immunotherapy remains the main impediment towards curative cancer therapy, which leads directly to treatment failure along with extended hospital stays, increased medical costs and high mortality. Therefore, increasing attention has been paid to nanotechnology-based delivery systems for overcoming drug resistance in cancer. In this respect, novel tumor-targeting nanomedicines offer fairly effective therapeutic strategies for surmounting the various limitations of chemotherapy, targeted therapy and immunotherapy, enabling more precise cancer treatment, more convenient monitoring of treatment agents, as well as surmounting cancer drug resistance, including multidrug resistance (MDR). Nanotechnology-based delivery systems, including liposomes, polymer micelles, nanoparticles (NPs), and DNA nanostructures, enable a large number of properly designed therapeutic nanomedicines. In this paper, we review the different mechanisms of cancer drug resistance to chemotherapy, targeted therapy and immunotherapy, and discuss the latest developments in nanomedicines for overcoming cancer drug resistance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel inorganic sonosensitizer (a-Mn-CoMo-LDH) was proposed for MRI-guided SDT. • Acid etching of Mn-CoMo-LDH successfully activated its ROS generation activity. • Doped Mn4+ decomposed H 2 O 2 into O 2 to alleviate the hypoxic tumor microenvironment. • Mn4+ consumed GSH to reduce its clearance of ROS and also generated Mn2+ for MRI. Sonodynamic therapy (SDT) has attracted increasing attention owing to its superior tissue penetration compared with other therapies. However, the development of multifunctional sonosensitizers with imaging capability and high production efficiency of reactive oxygen species (ROS) is still a challenge for current sonodynamic cancer therapy. Herein, we report the design and preparation of amorphous 2D Mn-doped CoMo-layered double hydroxide (a-Mn-CoMo-LDH) nanosheets (NSs) through acid etching-induced crystalline-to-amorphous phase transformation as a highly active nano-agent for magnetic resonance imaging (MRI)-guided SDT. The a-Mn-CoMo-LDH NSs exhibit superior ROS production capacity compared with amorphous CoMo-LDH NSs (∼1.3 times) and crystalline Mn-CoMo-LDH NSs (∼3.9 times) under ultrasound (US) irradiation, which is ∼ 9.9 times of the previously reported TiO 2 sonosensitizer. The doped Mn4+ in the a-Mn-CoMo-LDH NSs can not only decompose H 2 O 2 into O 2 to alleviate the hypoxia level in tumor microenvironment (TME), but also consume glutathione (GSH) to reduce its clearance of ROS, promoting the SDT performance synergistically. Importantly, the GSH consumption can partially reduce the Mn4+ to Mn2+ within the tumors, which can serve as an agent for T 1 -weighted MRI, thus endowing the a-Mn-CoMo-LDH NSs with excellent MRI capability. Therefore, the as-prepared a-Mn-CoMo-LDH NSs with polyethylene glycol modification can be used as an efficient nano-agent for MRI-guided SDT, which can effectively achieve apoptosis of cancer cells in vitro and eradication of tumors in vivo under US irradiation. [ABSTRACT FROM AUTHOR]

Currently, reactive oxygen species (ROS)-induced apoptosis systems have drawn increasing attention in cancer therapy, owing to their specific tumor inhibition ability and great biocompatibility. Herein, we developed a highly dispersed nano-enzyme based on the assembly of natural glucose oxidase (GOD) onto CoFe-layered double hydroxides (CoFe-LDHs) monolayer nanosheets. By virtue of the high dispersion of Fe3+ within the host layer, the CoFe-LDHs nanosheets exhibit a collaborative enhanced Fenton catalytic activity with a rate constant of 3.26 × 10−4 s−1, which is 1–3 orders of magnitude higher than other iron-containing Fenton reaction agents. Subsequently, with a massive H 2 O 2 triggered by GOD, GOD/CoFe-LDHs nanohybrid converts a cascade of glucose into hydroxyl radicals under tumor acid conditions, which is validated by a high maximum velocity (V max = 2.23 × 10−6 M) and low Michaelis–Menten constant (K M = 5.40 mM). Through the intracellular catalytic Fenton reaction within the tumor environment, both in vitro and in vivo results demonstrate the excellent antitumor effect of GOD/CoFe-LDHs. Therefore, a self-supplied, ultra-efficient and sequential catalytic tumor-specific therapy has been achieved based on GOD/CoFe-LDHs nano-enzyme, which holds great promise in clinical cancer therapy with minimum side effects. Highly dispersed GOD/CoFe-LDHs nano-enzyme is fabricated by immobilizing natural glucose oxidase (GOD) onto CoFe-LDHs monolayer nanosheets, which provides a paradigm for cancer specific therapy through self-supplied and ultra-efficient intracellular Fenton reaction. Image 1 [ABSTRACT FROM AUTHOR]

Emerging evidences have demonstrated that gold nanoparticles (AuNPs) have been used for cancer treatment. The aim of this study was to investigate the effects and molecular mechanisms of AuNPs on papillary thyroid carcinoma (PTC) cells (BCPAP and TPC-1). Characterizations of AuNPs were detected by UV-Vis spectra, transmission electron microscopy (TEM), and dynamic light scattering (DLS). Cell proliferation and apoptosis, migration, and invasion of PTC cells were evaluated by MTT, flow cytometry, wound healing, and transwell assays, respectively. Furthermore, qRT-PCR and western blot assays were performed to assess the protein expressions related to apoptosis and migration including caspase-3, caspase-9, Bax, Bcl-2, MMP-2, and MMP-9. The study revealed that AuNPs significantly suppressed cell viability, migration, and invasion and remarkably induced apoptosis of BCPAP and TPC-1 cells compared with the control group. Moreover, AuNPs negatively regulated the expression of CCT3 and silencing of CCT3 obviously promoted the proliferation, migration, and invasion inhibition and apoptosis induction of PTC cells combined with AuNPs. Collectively, these results highlighted the potential application of AuNPs in PTC target therapy. [ABSTRACT FROM AUTHOR]

Recently, theranostic has drawn tremendous attention by virtue of the nanotechnology development and new material exploration. Herein, we reported a novel theranostic system by loading Au nanoclusters (AuNCs) and Chlorin e6 (photosensitizer, Ce6) onto the monolayer nanosheet surface of Gd-doped layered double hydroxide (Gd-LDH). The as-prepared Ce6&AuNCs/Gd-LDH exhibits a largely enhanced fluorescence quantum yield (QY) of 18.5% relative to pristine AuNCs (QY = 3.1%) as well as superior T 1 magnetic resonance imaging (MRI) performance ( r 1  = 17.57 mM −1 s −1 ) compared with commercial MRI contrast agent (Gd(III)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (Gd-DOTA): r 1  ≈ 3.4 mM −1 s −1 ), resulting from a synergistic effect between AuNCs and Gd-LDH. In addition, both in vitro and in vivo therapeutic evaluations demonstrate an efficient dual-modality imaging guided anticancer performance, especially the synergetic enhanced magnetic resonance/fluorescence (MR/FL) visualization of tumor site. Therefore, this work demonstrates a successful paradigm for the design and preparation of LDHs monolayer-based theranostic material, which holds great promises in practical applications. [ABSTRACT FROM AUTHOR]

Multidrug resistance (MDR) is a serious phenomenon employed by cancer cells which hampers the success of cancer pharmacotherapy. One of the common mechanisms of MDR is the overexpression of ATP-binding cassette (ABC) efflux transporters in cancer cells such as P-glycoprotein (P-gp/ABCB1), multidrug resistance-associated protein 2 (MRP2/ABCC2), and breast cancer resistance protein (BCRP/ABCG2) that limits the prolonged and effective use of chemotherapeutic drugs. Researchers have found that developing inhibitors of ABC efflux transporters as chemosensitizers could overcome MDR. But the clinical trials have shown that most of these chemosensitizers are merely toxic and only show limited or no benefits to cancer patients, thus new inhibitors are being explored. Recent findings also suggest that efflux pumps of the ABC transporter family are subject to epigenetic gene regulation. In this review, we summarize recent findings of the role of ABC efflux transporters in MDR. [ABSTRACT FROM AUTHOR]

Background: The chemotherapy drug doxorubicin (Dox) is widely used for treating a variety of cancers. However, its high cardiotoxicity hampered its clinical use. Exosomes derived from stem cells showed a therapeutic effect against Dox-induced cardiomyopathy (DIC). Previous studies reported that exosomes derived from mesenchymal stem cells (MSCs) pretreated with macrophage migration inhibitory factor (MIF) (exosomeMIF) showed a cardioprotective effect through modulating long noncoding RNAs/microRNAs (lncRNAs/miRs). This study aimed to investigate the role of exosomeMIF in the treatment of DIC. Results: Exosomes were isolated from control MSCs (exosome) and MIF-pretreated MSCs (exosomeMIF). Regulatory lncRNAs activated by MIF pretreatment were explored using genomics approaches. Fluorescence-labeled exosomes were tracked in vitro by fluorescence imaging. In vivo and in vitro, miR-221-3p mimic transfection enforced miR-221-3p overexpression, and senescence-associated β-galactosidase assay was applied to test cellular senescence. Exosomal delivering LncRNA-NEAT1 induced therapeutic effect in vivo was confirmed by echocardiography. It demonstrated that exosomesMIF recovered the cardiac function and exerted the anti-senescent effect through LncRNA–NEAT1 transfer against Dox. TargetScan and luciferase assay showed that miR-221-3p targeted the Sirt2 3′-untranslated region. Silencing LncRNA–NEAT1 in MSCs, miR-221-3p overexpression or Sirt2 silencing in cardiomyocytes decreased the exosomeMIF-induced anti-senescent effect against Dox. Conclusions: The results indicated exosomeMIF serving as a promising anti-senescent effector against Dox-induced cardiotoxicity through LncRNA–NEAT1 transfer, thus inhibiting miR-221-3p and leading to Sirt2 activation. The study proposed that exosomeMIF might have the potential to serve as a cardioprotective therapeutic agent during cancer chemotherapy. [ABSTRACT FROM AUTHOR]

Abstract: MicroRNA-148a (miR-148a) which suppresses tumor growth by directly decreasing DNMT1 expression has been demonstrated as an important role for cancer therapy. The mechanisms for miR-148a in cancer will become potential future researches. [Copyright &y& Elsevier]