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Breaking the threshold of intracellular reactive oxygen species (ROS) levels can cause nonspecific oxidative damage to proteins and lead to the Fenton reaction-mediated exogenous ROS production to be a new promising anticancer strategy. However, the problems, including the inefficient transport of metal catalysts and insufficient endogenous hydrogen peroxide (H 2 O 2 ) content in cells, still need to be improved. In this study, a functional nanosystem encapsulated with benzothiazole complexes (FeTB 2 ) and the photosensitizer indocyanine green (ICG) was designed for highly effective antitumor therapy. The surface of the nanocarriers was modified with dihydroartemisinin (DHA)-grafted polyglutamic acid. The induced hyperthermia enables the lipid-polymer shell to depolymerize, releasing FeTB 2 . The released FeTB 2 could kill tumor cells in two different ways by inhibiting DNA replication and catalyzing H 2 O 2 to produce active •OH. Moreover, the conjugated DHA could increase the amount of peroxides in tumor cells and significantly enhance the ROS yield. This work has provided solid evidence that the present nanosystem enables a significant effect on tumor killing through the combined inhibition of DNA replication and ROS-mediated oxidative damage by regulation of the tumor microenvironment, providing a ROS-mediated high-efficiency antitumor strategy.

Three peroxidovanadium(v) compounds with different ligands (L1-L3) {L1 = N-tris(hydroxymethyl)methylglycine; L2 = ethylenediamine-N,N'-diacetic acid; L3 = 2,2-[(2-amino-2-oxoethyl)imino]diacetic acid} were first synthesized, characterized and further investigated for their anticancer activities under the mediation of transition metal cations. Encouragingly, all compounds showed preferentially enhanced cytotoxicity toward cancer cells (MCF-7 and A549) compared to normal cells (BEAS-2B) under the mediation of transition metal cations (Mn2+ or Fe2+), especially for Mn2+. It was noted that cell death was triggered by the transition metal cation-mediated peroxidovanadium(v) compounds through the induction of early apoptosis, inhibition of cell cycles, and boosting the generation of intracellular reactive oxygen species (ROS). Mechanistic studies further elucidated the vital roles of an acidic environment and transition metal cations for the anticancer activity of peroxidovanadium(v) compounds. Therefore, this study will offer precious insight into the development of the transition metal cation-mediated peroxidovanadium(v) compounds for further clinical translation.

The acridine derivatives can interact with the double-stranded DNA, which is regarded as the biological target of the anticancer drugs in cancer treatment. We designed and synthesized a new series of 1,3-dimethyl-6-nitroacridine derivatives as potential DNA-targeted anticancer agents. These compounds could partially intercalate into the calf thymus DNA, differing from the parent acridine. The results showed that the substitutions of the acridine ring had great effect on DNA binding affinity. The binding constants determined by UV-vis spectroscopy were found to be 10 5  M -1 grade. Anticancer activity of these compounds was screened using MTT assay. Most compounds inhibited 50% cancer cell growth at concentration below 30 μM, the results were consistent with the DNA binding ability. Compounds 1 and 6 were found to have more effective cytotoxicity, especially in human breast cancer cell lines. To investigate the action mechanism, we studied cell apoptosis, morphological changes, and cell cycle distribution in MCF-7 and MDA-MB-231 cells. Compounds 1 and 6 caused MCF-7 and MDA-MB-231 cells death due to apoptosis, and induced cell apoptosis in a dose-dependent manner. They also had significant effect on cell cycle progression and arrested cell cycle at G2/M phase. The results demonstrated that compounds 1 and 6 are promising candidates for cancer treatment.

A combination of photothermal-chemotherapy has received widespread attention in drug delivery systems for cancer treatment. However, the combination therapy operated in subcellular organelles, such as mitochondria, has been rarely reported. Herein, we designed a novel near-infrared (NIR) triggered dual-targeted nanoplatform (FA/TPP-DINPs) based on mitochondrial combined photothermal-chemotherapy by co-loading FDA-approved NIR dye indocyanine green (ICG) and anticancer drug doxorubicin (DOX). The resulting nanoparticles showed a monodispersed sphere and excellent colloidal stability. Specially, the simultaneous introduction of targeted ligands folic acid (FA) and triphenylphosphine (TPP) to nanoparticles significantly promoted the cellular internalization and mitochondrial co-localization of nanoparticles. Moreover, the encapsulated dye could convert NIR light into heat with high efficiency, which makes the FA/TPP-DINPs an effective platform for mitochondrial combination therapy with chemotherapy drug DOX. Meanwhile, the thermal expansion in response to the change of temperature after sustained 808 nm laser irradiation could cause the disintegration of nanoparticles, which triggered the rapid release of DOX from nanoparticles. As expected, the prepared FA/TPP-DINPs exhibited evidently enhanced cytotoxicity and preeminent combination therapy efficiency on MCF-7 cells. Thus, the NIR triggered dual-targeted nanoplatform provides a new drug delivery strategy for mitochondrial combined photothermal-chemotherapy of cancer.

The complexes of the type [PtCl(L2)(ACRAMTU)](NO 3 ) 2 (ACRAMTU = 1-[2-(acridin-9-ylamino)ethyl]-1,3-dimethylthiourea) were synthesized: PT-ACRAMTU (1), L2 = ethane-1,2-diamine (en); PT(dach)-ACRAMTU (2), L2 = (1R,2R)-1,2-diaminocyclohexane (dach); PT(pda-OH)-ACRAMTU (3), L2 = 2-hydroxy-1,3-propanediamine (pda-OH). The complexes containing diverse diamines exhibit different DNA binding capacity and cytotoxicity. Complex 3 shows excellent capability not only on the strongest non-cisplatin-type DNA damage, but also superior anticancer activity in NCI-H460 cells (IC 50  = 0.23 ± 0.05 μM). For overcoming water insolubly and side effects, we encapsulated complex 3 into liposomes. PT@NPs were characterized in terms of particle size, morphology, drug loading capacity (DLC), encapsulation efficiency (EE) and stability. In vitro triggered release showed that the release of the platinum drug was steerable and the release rate was fast under low pH (<7.0) and high temperature (>T m  = 41 °C). PT@NPs showed significant inhibitory effect in NCI-H460 cells. Flow cytometry analysis indicates G0/G1 phase arrest of cells treated with complex 3, whereas cells treated with cisplatin progress to G2/M of the cell cycle. The mechanistic differences validate that complex 3 is a potent anticancer agent superior than current clinical platinum-based therapies. PT@NPs have the potential in drug delivery systems (DDS) for non-small cell lung cancer (NSCLC) therapy., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The functionalized nanoparticles have been widely studied and reported as carriers of drug transport recently. Furthermore, many groups have focused more on developing novel and efficient treatment methods, such as photodynamic therapy and photothermal therapy, since both therapies have shown inspiring potential in the application of antitumor. The mentioned treatments exhibited the superiority of cooperative manner and showed the ability to compensate for the adverse effects caused by conventional monotherapy in proposed strategies. In view of the above descriptions, we formulated a thermosensitive drug delivery system, which achieved the enhanced delivery of cisplatin and two photosensitizers (ICG and Ce6) by dual-targeting traction. Drawing on the thin film hydration method, cisplatin and photosensitizers were encapsulated inside nanoparticles. Meanwhile, the targeting peptide cRGD and targeting molecule folate can be modified on the surface of nanoparticles to realize the active identification of tumor cells. The measurements of dynamic light scattering showed that the prepared nanoparticles had an ideal dispersibility and uniform particle size of 102.6 nm. On the basis of the results observed from confocal laser scanning microscope, the modified nanoparticles were more efficient endocytosed by MCF-7 cells as a contrast to SGC-7901 cells. Photothermal conversion-triggered drug release and photo-therapies produced a significant apoptosis rate of 85.9% on MCF-7 cells. The distinguished results made it believed that the formulated delivery system had conducted great efforts and innovations for the realization of concise collaboration and provided a promising strategy for the treatment of breast cancer.

DNA is considered to be one of the most promising targets for anticancer agents. Acridine analogues have anticancer activity based on DNA binding and topoisomerases inhibition. However, due to the side effects, resistance and low bioavailability, a few have entered into clinical usage and the mechanisms of action are not fully understood. Novel acridine derivatives are needed for effective cancer therapy. A series of novel 3-nitroacridine-based derivatives were synthesized, their DNA binding and anticancer activities were evaluated. The chemical modifications at position 9 of the 3-nitroacridine were crucial for DNA affinity, thus optimizing anticancer activity. UV-Vis and circular dichroism (CD) spectroscopy indicated interaction of compounds with DNA, and the binding modes were intercalation and groove binding. MTT assay and clonogenic assay showed that compounds 1, 2 and 3 had obvious cell growth inhibition effect. They induced cell apoptosis in human breast cancer cells in a dose-dependent manner, and exhibited anticancer effect via DNA damage as well as cell cycle arrest at G0/G1 phage. Using confocal fluorescent microscope, the apoptotic features were observed. The results suggested that compounds 1-3 with high DNA binding affinity and good inhibitory effect of cancer cell proliferation can be developed as prime candidates for further chemical optimization., (Copyright © 2018 Elsevier Inc. All rights reserved.)

A novel core-shell type nanoparticle (CSNP) was designed here to target co-delivery of doxorubicin (DOX) and photosensitizer indocyanine green (ICG) to tumor sites by the aid of NIR induced photothermal conversion effect for the purpose of synergistic chemo-photothermal cancer therapy. The electrostatically self-assembled CSNPs were prepared by amino-functionalized mesoporous silica nanoparticles (MSN-NH 2 ) as the positive inner core and DSPE-PEG 2000 -COOH and DSPE-PEG 2000 -FA modified lecithin as the negative outer shell. The obtained CSNPs were nanospheres with a uniform size of 47 nm, which were kept stable at 4 °C in PBS (pH = 7). Research on the release of NIR stimulus (808 nm, 1.54 W cm -2 , 6 min) manifested that the release property of the CSNPs was controllable under low pH conditions. In addition, specific concentration (40 μg ml -1 ) ICG-loaded CSNPs, achieving an appropriate temperature up to 45 °C, indicated a desired photothermal conversion efficiency. For targeting the folate receptor, the folate modified CSNPs enabled us to reach a higher cellular uptake by the mean fluorescence intensity. In vitro cell assay, the prepared CSNPs showed outstanding inhibitory efficiency (2.07% cell viability and 91.8% cell apoptosis) on MCF-7 cells for 24 h when irradiated by an 808 nm laser with a power of 1.54 W cm -2 for 6 min. Our research highlights that the prepared nanoparticles hold potential promise for cancer treatment based on photothermal conversion performance and FA-targeted delivery.

Polymeric biomaterials that can be smartly disassembled through the cleavage of the covalent bonds in a controllable way upon an environmental stimulus such as pH change, redox, special enzymes, temperature, or ultrasound, as well as light irradiation, but are otherwise stable under normal physiological conditions have attracted great attention in recent decades. The 2-(4-aminophenyl) benzothiazole molecule (CJM-126), as one of the benzothiazole derivatives, has exhibited a synergistic effect with cisplatin (CDDP) and restrains the bioactivities of a series of human breast cancer cell lines. In our study, novel NIR-responsive targeted binary-drug-loaded nanoparticles encapsulating indocyanine green (ICG) dye were prepared as a new co-delivery and combined therapeutic vehicle. The prepared drug-loaded polymeric nanoparticles (TNPs/CDDP-ICG) are stable under normal physiological conditions, while burst drugs release upon NIR laser irradiation in a mild acidic environment. The results further confirmed that the designed co-delivery platform showed higher cytotoxicity than the single free CDDP due to the synergistic treatment of CJM-126 and CDDP in vitro. Taken together, the work might provide a promising approach for effective site-specific antitumor therapy.

Dysregulated autophagy is involved in various human disorders including cancer. An autophagy-associated cell death pathway can be seen as a back-up cell death mechanism in cancer cells that are deficient in the apoptosis pathway. Therefore, many attempts have been made to induce autophagy for anticancer therapy. Anti-apoptotic Bcl-2 family proteins Bcl-2 and Bcl-xL can inhibit autophagy via binding to the BH3-only protein Beclin 1, an essential autophagy stimulator. In a previous study, we discovered several small molecule Beclin 1 mimetics as autophagy inducers through high-throughput screening and structural optimization, in which 3-nitroacridine warrants further exploration. Here, a series of novel 3-nitroacridine derivatives were designed, synthesized, and their pharmaceutical activities and mechanism of action were investigated against gastric cancer cell lines. As a result, compounds 3, 4, and 9 displayed potent cytotoxicity and induced autophagy in MGC-803 and SGC-7901 gastric cancer cells. Besides, compounds 3 and 9 also inhibited the migration of SGC-7901 cells. The development of 3-nitroacridine analogues as autophagy inducers is not only likely to be a potential strategy for cancer therapy, but it will also facilitate a better understanding of the complicated roles of autophagy in normal physiology and pathophysiology. [ABSTRACT FROM AUTHOR]