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The ataxia telangiectasia-mutated and Rad3-related protein (ATR) plays a crucial role in regulating the cellular DNA-damage response (DDR), making it a promising target for antitumor drug development through synthetic lethality. In this study, we present the discovery and detailed characterization of AD1058, a highly potent and selective ATR inhibitor, with good preclinical pharmacokinetic profiles. AD1058 exhibits superior efficacy in inhibiting cell proliferation, disrupting the cell cycle, and inducing apoptosis compared to AZD6738. AD1058 displays potent antitumor effects as a single agent or in combination with clinically approved tumor therapies such as PARP inhibitors, ionizing radiotherapy, or chemotherapy in vivo. Considering its enhanced ability to permeate the blood-brain barrier, AD1058 is a promising clinical candidate for the treatment of brain metastases and leptomeningeal metastases in solid tumors. Additionally, among reported ATR inhibitors, AD1058 features the shortest synthesis route and the highest efficiency to date.

So far, relatively few small molecules have been reported to promote tubulin degradation. Our previous studies have found that compound 2 , a noncovalent colchicine-site ligand, was capable of promoting αβ-tubulin degradation. To further improve its antiproliferative activity, 66 derivatives or analogues of 2 were designed and synthesized based on 2 -tubulin cocrystal structure. Among them, 12b displayed nanomolar potency against a variety of tumor cells, including paclitaxel- and adriamycin-resistant cell lines. 12b binds to the colchicine site and promotes αβ-tubulin degradation in a concentration-dependent manner via the ubiquitin-proteasome pathway. The X-ray crystal structure revealed that 12b binds in a similar manner as 2 , but there is a slight conformation change of the B ring, which resulted in better interaction of 12b with surrounding residues. 12b effectively suppressed tumor growth at an i.v. dose of 40 mg/kg (3 times a week) on both A2780S (paclitaxel-sensitive) and A2780T (paclitaxel-resistant) ovarian xenograft models, with respective TGIs of 92.42 and 79.75% without obvious side effects, supporting its potential utility as a tumor-therapeutic compound.

Uveal melanoma (UM) is the most common primary intraocular malignancy among adults. Despite significant advances in diagnosis and treatment, the general mortality of UM remains alarmingly high. This calls for the development of new approaches for the treatment of UM, such as targeted cancer therapy. CD71, also known as transferrin receptor 1, is overexpressed in UM cell lines and tissues. Herein, we report the development of a CD71-specific aptamer targeting the XQ-2d-MMAE conjugate that can distinguish UM cells from normal human uveal melanocytes. The cytotoxic drug monomethyl auristatin E (MMAE) could be easily coupled onto XQ-2d, a DNA aptamer that specifically targets CD71, to achieve efficiently targeted cancer growth inhibition in a mouse xenograft model, thus implying that XQ-2d-MMAE might be developed into a promising novel anti-tumor agent for the treatment of UM. Collectively, our results demonstrated that CD71 is a reliable target for drug delivery in UM and could be utilized as a model to explore aptamer-mediated targeted UM treatment strategies.

Hydroxamic acid group is one of the characteristic pharmacophores of histone deacetylase (HDAC) inhibitors. But here, we discovered a series of hydroxamic acid-based microtubule destabilizing agents (MDAs), which were derived from shortening the length of the linker in HDAC6 inhibitor SKLB-23bb. Interestingly, the low nanomolar antiproliferative activity of these MDAs depended on the presence of hydroxamic acid groups, but their inhibitory effects on HDAC were lost. Among them, 12b showed favorable metabolism stability, high bioavailability, and potent antitumor activity in multidrug-resistant cell lines and A2780/T xenograft model. More importantly, in the patient-derived xenograft models of triple-negative breast cancer and osimertinib-resistant non-small-cell lung cancer, both 20 mg/kg oral and 10 mg/kg intravenous administration of 12b could induce more than 70% tumor inhibition without obvious toxicity. Overall, we discovered that 12b , as a novel MDA based on hydroxamic acid, could serve as a potential MDA for further investigation.

Chemodynamic therapy (CDT) is a kind of method utilizing hydroxyl radicals ( • OH) generated by Fenton or Fenton-like reactions in situ to kill tumor cells. Copper, a cofactor of many intracellular enzymes, which has good biocompatibility, is a transition metal with extremely high efficiency in the Fenton-like reaction. However, when the intracellular free copper exceeds the threshold, it will bring serious side effects. Hence, we used the chelation between glutathione (GSH) and copper ions to produce a nanocatalytic drug, which was named as Cu-GSSG NPs, to fix free copper. With the aid of hydrogen peroxide (H 2 O 2 ) in vitro , Cu-GSSG NPs catalyzed it to • OH radicals, which could be confirmed by the electron spin resonance spectrum and the degradation experiment of methylene blue. Based on these results, we further studied the intracellular properties of Cu-GSSG NPs and found that Cu-GSSG NPs could react with the overexpressed H 2 O 2 in tumor cells to produce • OH radicals effectively by the Fenton-like reaction to induce cell death. Therefore, Cu-GSSG NPs could be a kind of potential "green" nanocatalytic drug with good biocompatibility to achieve CDT.

Myeloid cell leukemia 1 (Mcl-1), which belongs to the Bcl-2 family of prosurvival proteins, is a key regulator of cancer cell survival. To date, few drug-like Mcl-1 inhibitors have been reported. Herein, we report the preparation of 10 copper complexes with 9-substituted β-carboline ligands that act as metal-based Mcl-1 inhibitors. Complex 14 was identified as a potent and selective Mcl-1 inhibitor with strong in vitro antitumor activity. Mechanistic studies demonstrated that complex 14 disrupted Mcl-1-Bax/Bak heterodimerization and induced Bax/Bak-dependent apoptosis. In addition, complex 14 significantly ( P < 0.001) inhibited tumor growth in vivo , induced tumor necrosis, and extended survival time in an NCI-H460 xenograft model. Furthermore, complex 14 showed no apparent toxicity in mice. Together, these findings indicate that complex 14 is a copper-based Mcl-1 inhibitor with high efficacy and low toxicity that could be developed for the treatment of Mcl-1-related cancers.

Here we provide an unprecedented biofactory where fluorescent dye-like complex xanthenes could be produced in an engineered Escherichia coli . Feeding the strain with toluquinol or hydroquinones resulted in production of novel "unnatural" natural products including four arthrocolins embedded with indolyltriphenyl quaternary carbons. Arthrocolins A - C potently inhibited various human cancer cell lines including paclitaxel-resistant cell line A549/Taxol and methicillin-resistant Staphylococcus aureus and immensely restored the sensitivity of intractable fluconazole-resistant human pathogen Candida albicans to fluconazole.

Agents inducing both apoptosis and autophagic death can be effective chemotherapeutic drugs. In our present work, we synthesized two organometallic gold(III) complexes harboring C^N ligands that structurally resemble tetrahydroisoquinoline (THIQ): Cyc-Au-1 (AuL 1 Cl 2 , L 1 = 3,4-dimethoxyphenethylamine) and Cyc-Au-2 (AuL 2 Cl 2 , L 2 = methylenedioxyphenethylamine). In screening their in vitro activity, we found both gold complexes exhibited lower toxicity, lower resistance factors, and better anticancer activity than those of cisplatin. The organometallic gold(III) complexes accumulate in mitochondria and induce elevated ROS and an ER stress response through mitochondrial dysfunction. These effects ultimately result in simultaneous apoptosis and autophagy. Importantly, compared to cisplatin, Cyc-Au-2 exhibits lower toxicity and better anticancer activity in a murine tumor model. To the best of our knowledge, Cyc-Au-2 is the first organometallic Au(III) compound that induces apoptosis and autophagic death. On the basis of our results, we believe Cyc-Au-2 to be a promising anticancer agent or lead compound for further anticancer drug development.

Hypoxia as one characteristic hallmark of solid tumors has been demonstrated to be involved in cancer metastasis and progression, induce severe resistance to oxygen-dependent therapies, and hamper the transportation of theranostic agents. To address these issues, an oxygen-self-produced sonodynamic therapy (SDT) nanoplatform involving a modified fluorocarbon (FC)-chain-mediated oxygen delivery protocol has been established to realize highly efficient SDT against hypoxic pancreatic cancer. In this nanoplatform, mesopores and FC chains of FC-chain-functionalized hollow mesoporous organosilica nanoparticle carriers can provide sufficient storage capacity and binding sites for sonosensitizers (IR780) and oxygen, respectively. In vitro and in vivo experiments demonstrate the nanoplatform involving this distinctive oxygen delivery protocol indeed breaks the hypoxia-specific transportation barriers, supplies sufficient oxygen to hypoxic PANC-1 cells especially upon exposure to ultrasound irradiation, and relieves hypoxia. Consequently, hypoxia-induced resistance to SDT is inhibited and sufficient highly reactive oxygen species (ROS) are produced to kill PANC-1 cells and shrink hypoxic PANC-1 pancreatic cancer. This distinctive FC-chain-mediated oxygen delivery method provides an avenue to hypoxia oxygenation and holds great potential in mitigating hypoxia-induced resistance to those oxygen-depleted therapies, e.g., photodynamic therapy, radiotherapy, and chemotherapy.

A series of chiral β-lactam bridged analogues (3-substituted 1,4-diaryl-2-azetidinones) of combretastatin A-4 (CA-4) were synthesized asymmetrically, and their antitumor activities were evaluated in vitro and in vivo. The cocrystal structure of tubulin in complex with compound 9 was determined by X-ray crystallography, which showed that 9 binds to the same site as colchicine with similar binding mode, and the absolute configuration of its C-4 was first identified and demonstrated to be critically important for their antiproliferative activities.

By targeting a new binding region at the interface between αβ-tubulin heterodimers at the colchicine binding site, we designed a series of 7-substituted 1-methyl-1,4-dihydroindeno[1,2-c]pyrazoles as potential tubulin polymerization inhibitors. Among the compounds synthesized, 2-(6-ethoxy-3-(3-ethoxyphenylamino)-1-methyl-1,4-dihydroindeno[1,2-c]pyrazol-7-yloxy)acetamide 6a and 2-(6-ethoxy-3-(3-ethoxyphenylamino)-1-methyl-1,4-dihydroindeno[1,2-c]pyrazol-7-yloxy)-N-hydroxyacetamide 6n showed noteworthy low nanomolar potency against HepG2, Hela, PC3, and MCF-7 cancer cell lines. In mechanism studies, 6a inhibited tubulin polymerization and disorganized microtubule in A549 cells by binding to tubulin colchicine binding site. 6a arrested A549 cells in G2/M phase that was related to the alterations in the expression of cyclin B1 and p-cdc2. 6a induced A549 cells apoptosis through the activation of caspase-3 and PARP. In addition, 6a inhibited capillary tube formation in a concentration-dependent manner. In nonsmall cell lung cancer xenografts mouse model, 6a suppressed tumor growth by 59.1% at a dose of 50 mg/kg (ip) without obvious toxicity, indicating its in vivo potential as anticancer agent.

Antitumor vaccine, which is promising for tumor therapy, has been extensively studied. Some encouraging results of chemically synthetic vaccine designs based on the tumor-associated antigen mucin 1 have been achieved. However, some shortcomings such as low efficiency and difficult purification restrict their clinical application. To overcome these difficulties, we designed a novel antitumor vaccine of glycopeptide nanoconjugates based on the multilayer self-assembly through the interaction of positive and negative charges. This vaccine formed the spherical structure and effectively activated the macrophage in vitro. Besides, it also induced high titer of antibodies against mucin 1 glycopeptide. The induced antibodies could highly bind to the tumor cells and effectively kill them by activation of the complement dependent cytotoxicity complex. This novel strategy provides a new way for the development of simple and effective antitumor vaccine.

Three water-soluble ruthenium(II) complexes with chiral 4-(2,3-dihydroxypropyl)-formamide oxoaporphine (FOA) were synthesized and characterized. It was found that these ruthenium(II) complexes exhibited considerable in vitro anticancer activities and that they were the effective stabilizers of telomeric and G-quadruplex-DNA (G4-DNA) in promoter of c-myc, which acted as a telomerase inhibitor targeting G4-DNA and induced cell senescence and apoptosis. Interestingly, the in vitro anticancer activity of 6 (LC-003) was higher than those of 4 (LC-001) and 5 (LC-002), more selective for BEL-7404 cells than for normal HL-7702 cells, and preferred to activate caspases-3/9. The different biological behaviors of the ruthenium complexes could be correlated with the chiral nature of 4-(2,3-dihydroxypropyl)-formamide oxoaporphine. More significantly, 6 exhibited effective inhibitory on tumor growth in BEL-7402 xenograft mouse model and higher in vivo safety than cisplatin. These mechanistic insights indicate that 6 displays low toxicity and can be a novel anticancer drug candidate.

Two G-quadruplex ligands [Pt(L(a))(DMSO)Cl] (Pt1) and [Pt(L(b))(DMSO)Cl] (Pt2) have been synthesized and fully characterized. The two complexes are more selective for SK-OV-3/DDP tumor cells versus normal cells (HL-7702). It was found that both Pt1 and Pt2 could be a telomerase inhibitor targeting G-quadruplex DNA. This is the first report demonstrating that telomeric, c-myc, and bcl-2 G-quadruplexes and caspase-3/9 preferred to bind with Pt2 rather than Pt1, which also can induce senescence and apoptosis. The different biological behavior of Pt1 and Pt2 may correlate with the presence of a 6-hydroxyl group in L(b). Importantly, Pt1 and Pt2 exhibited higher safety in vivo and more effective inhibitory effects on tumor growth in the HCT-8 and NCI-H460 xenograft mouse model, compared with cisplatin. Taken together, these mechanistic insights indicate that both Pt1 and Pt2 display low toxicity and could be novel anticancer drug candidates.

Dual endosomal pH-sensitive micelles were designed and fabricated to deliver doxorubicin (DOX) for treating breast cancer based on a poly(2-ethyl-2-oxazoline) (PEOz)-DOX (PEOz-hyd-DOX) conjugate. PEOz-hyd-DOX was successfully synthesized by connecting DOX to PEOz via an acid cleavable hydrazone linker and self-assembled into nanosized micelles, which further physically encapsulated DOX. The conjugate and DOX-loaded conjugate micelles displayed faster release of DOX at pH 5.0 than at pH 7.4. This pH-dependent release behavior might assist the quick diffusion of DOX from acidic endosomes or lysosomes and the intracellular transfer into the nucleus after internalization, which was confirmed by confocal laser scanning microscopy images. As expected, PEOz-hyd-DOX conjugate and DOX-loaded conjugate micelles maintained cytotoxicity of DOX. In addition, the dual endosomal pH-sensitive micelles were found to substantially enhance antitumor efficacy and reduce side effects compared with free DOX. Therefore, PEOz-hyd-DOX conjugate-based micelles might be potential drug delivery vehicles of DOX for safe and effective breast cancer therapy.

CXCL12 binds to CXCR4, promoting both chemotaxis of lymphocytes and metastasis of cancer cells. We previously identified small molecule ligands that bind CXCL12 and block CXCR4-mediated chemotaxis. We now report a 1.9 Å resolution X-ray structure of CXCL12 bound by such a molecule at a site normally bound by sY21 of CXCR4. The complex structure reveals binding hot spots for future inhibitor design and suggests a new approach to targeting CXCL12-CXCR4 signaling in drug discovery.

Spherical nanoparticles as a classic delivery vehicle for anticancer drugs have been extensively investigated, but study on the shape of nanoparticles has received little attention until now. Here, a nonspherical poly(ethylene glycol) (PEG)-stabilized bilayer nanodisk consisting of 1,2-distearyl-sn-glycero-3-phosphocholine (DSPC) and PEG5000-glyceryl distearate (PEG5K-GCDS) was prepared for doxorubicin delivery, called DOX-Disks. The prepared disks were open bilayer structures, with a hydrophobic discoid center built by DSPC and a hydrophilic PEG edge. Mean particle diameter of the disk was 80.14 nm, and the disk height was about 6 nm with aspect ratio about 12. Encapsulation efficiency of DOX-Disks was as high as 96.1%, and DOX release from DOX-Disks was pH-dependent (25.6% of total DOX released at 24 h in pH 7.4). The pharmacokinetic performances showed that DOX-Disks demonstrated long circulation time in blood and larger AUC (11.7-fold of t1/2 and 31.7-fold of AUC) in rats compared with DOX solutions (DOX-Sol). Tissue distribution in H22 tumor bearing mice demonstrated higher tumor accumulation (9.7-fold) and lower heart toxicities (25.7-fold) at 48 h after iv administration, in comparison with DOX-Sol. In addition, DOX-Disks exhibited much effectiveness in inhibiting tumor cell growth, and the IC50 values were 2.03, 0.85, and 0.86 μg/mL for DOX-Sol and 0.23, 0.24, and 0.20 μg/mL for DOX-Disks after treatment for 48, 72, and 96 h against MCF-7/Adr cells, respectively. DOX-Disks were taken up into MCF-7/Adr cells via energy-dependent endocytosis processes, involved in clathrin-mediated, macropinocytosis-mediated, and non-clathrin- and non-caveolae-mediated endocytosis pathways. In summary, such PEG-stabilized bilayer nanodisks could be one of the promising carriers for antitumor drugs via extended blood circulation and improved tumor distribution.

A series of 6-substituted and 5-fluoro-6-substituted uridine derivatives were synthesized and evaluated for their potential as anticancer agents. The designed molecules were synthesized from either fully protected uridine or the corresponding 5-fluorouridine derivatives. The mononucleotide derivatives were used for enzyme inhibition investigations against ODCase. Anticancer activities of all the synthesized derivatives were evaluated using the nucleoside forms of the inhibitors. 5-Fluoro-UMP was a very weak inhibitor of ODCase. 6-Azido-5-fluoro and 5-fluoro-6-iodo derivatives are covalent inhibitors of ODCase, and the active site Lys145 residue covalently binds to the ligand after the elimination of the 6-substitution. Among the synthesized nucleoside derivatives, 6-azido-5-fluoro, 6-amino-5-fluoro, and 6-carbaldehyde-5-fluoro derivatives showed potent anticancer activities in cell-based assays against various leukemia cell lines. On the basis of the overall profile, 6-azido-5-fluoro and 6-amino-5-fluoro uridine derivatives exhibited potential for further investigations.

We report a method to generate bifunctional antibodies by grafting full-length proteins into constant region loops of a full-length antibody or an antigen-binding fragment (Fab). The fusion proteins retain the antigen binding activity of the parent antibody but have an additional activity associated with the protein insert. The engineered antibodies have excellent in vitro activity, physiochemical properties, and stability. Among these, a Her2 × CD3 bispecific antibody (BsAb) was constructed by inserting an anti-Her2 single-chain variable fragment (ScFv) into an anti-CD3 Fab. This bispecific antibody efficiently induces targeted cell lysis in the presence of effector cells at as low as sub-picomolar concentrations in vitro. Moreover, the Her2 × CD3 BsAb shows potent in vivo antitumor activity in mouse Her22+ and Her21+ xenograft models. These results demonstrate that insertion of a full-length protein into non-CDR loops of antibodies provides a feasible approach to generate multifunctional antibodies for therapeutic applications. [ABSTRACT FROM AUTHOR]