Low Toxicity of Metal-Organic Framework MOF-74(Co) Nano-Particles In Vitro and In Vivo.

With the rapid development of metal-organic frameworks (MOF), the toxicity and environmental safety of MOF materials should be thoroughly investigated. The behaviors and bio-effects of MOF materials after oral exposure are largely unknown. In this study, we performed a pilot toxicity evaluation of MOF-74(Co) nanoparticles (NPs) both in vitro and in vivo. The cell viability and cell cycle were monitored after LO2 cells were incubated with MOF-74(Co). The Co contents, bodyweight, serum biochemistry, histopathological changes, and oxidative stress parameters were measured after oral exposure to MOF-74(Co) NPs in mice. LO2 cells showed viability loss at 100 mg/L. The cell cycle arrest was more sensitive, which was observed even at 12.5 mg/L. MOF-74(Co) NPs led to a significant accumulation of Co in the liver and kidneys. No bodyweight loss was observed and the serum biochemical index was mainly unchanged. Except for slight inflammation, the histopathological images of the liver and kidneys after oral exposure to MOF-74(Co) NPs were normal compared to the control. Meaningful oxidative stress was found in the liver and kidneys. The results collectively indicated the low toxicity of MOF-74(Co) NPs after oral exposure in mice.

Discovery of 2-Methyl-2-(4-(2-methyl-8-(1H-pyrrolo[2,3-b]pyridin-6-yl)-1H-naphtho[1,2-d]imidazol-1-yl)phenyl)propanenitrile as a Novel PI3K/mTOR Inhibitor with Enhanced Antitumor Efficacy In Vitro and In Vivo.

PI3K/Akt/mTOR signaling pathway is a validated drug target for cancer treatment that plays a critical role in controlling tumor growth, proliferation, and apoptosis. However, no FDA-approved PI3K/mTOR dual inhibitor exists. Thus, a candidate with a better curative effect and lower toxicity is still urgently needed. Herein, we design, synthesize, and evaluate compounds belonging to a novel series of 2-methyl-1H-imidazo[4,5-c]quinoline scaffold derivatives as PI3K/mTOR dual inhibitors. Among them, compound 8o was identified as a novel candidate with excellent kinase selectivity. It manifested remarkable antiproliferative activities against SW620 and HeLa cells. Western blot and immunohistochemical analysis results proved that 8o could regulate the PI3K/AKT/mTOR signaling pathway by inhibiting the phosphorylation of AKT and S6 proteins. Additionally, 8o presented a favorable pharmacokinetic property (oral bioavailability of 76.8%) and significant antitumor efficacy in vivo without obvious toxicity. Collectively, these results indicated that 8o is a promising agent for cancer treatment and merits further development.

Synthesis and biological evaluation of a tumor-selective degrader of PARP1.

Poly (ADP-ribose) polymerase (PARP) inhibitors show potent antiproliferative activity in treatment with triple-negative breast cancer (TNBC) when combined with chemotherapeutic drugs. However, the emergence of safety issues and drug-resistance of PARP inhibitors prompt us to search for new strategies. It was proved that Proteolysis Targeting Chimeras (PROTACs) is more effective than traditional small molecule which can induce target proteins degradation rather than inhibition. In this article, based on the Olaparib derivatives and cereblon (CRBN) E3 ligase ligands, a series of PARP1 degraders, with linkers bearing different length and type were designed and synthesized. Among them, compound LB23 showed efficacious antiproliferative activity in various human cancer cells and can induce PARP1 protein degradation effectively. Moreover, LB23 showed 60-fold degradation selectivity in tumor cells with low degradation toxicity in normal cells. This study shows that the PROTAC tumor selectivity can be optimized by tuning the length and composition of the linker.

Selective degradation of PARP2 by PROTACs via recruiting DCAF16 for triple-negative breast cancer.

Triple negative breast cancer (TNBC) is a complex and heterogeneous neoplasm, and till now no effective therapies are available. PARP inhibitors, which target DNA repair, are lethal to those cells that have impaired homologous recombination (HR) pathway. So, PARP inhibitors might exert promising results in the treatment of BRCA-mutated TNBC, but show compromised effect to those wild-type TNBC. Herein, we describe a novel PROTACs C8, which was obtained by conjugating PARP1/2 inhibitor Olaparib to KB02, can induce potent and specific degradation of PARP2 by recruiting DCAF16 E3 ligase for treatment of wild-type TNBC. Moreover, C8 exhibits therapeutic potential in TNBC cell lines MDA-MB-231 both in vitro and in vivo. These studies demonstrated that the DCAF16 E3 ligases can be used in PARP2 PROTACs design, and C8, as a novel PARP2 selective DCAF16 based PROTACs, might be a promising lead compound for the treatment of BRCA-wild-type TNBC.

Biocompatible zinc gallogermanate persistent luminescent nanoparticles for fast tumor drainage lymph node imaging in vivo.

Tumor drainage lymph node identification and dissection are crucial for the oncological surgery to prevent/delay the recurrence. However, commercial imaging reagents distinguish the lymph nodes by staining them dark, which would be seriously interfered by blood and surrounding tissues. In this study, we reported the Cr3+/Pr3+-doped zinc gallogermanate persistent luminescent nanoparticles (PLNPs) for fast tumor drainage lymph node imaging with high contrast. PLNPs were synthesized by citrate sol-gel method and dispersed in Tween 80 for in vivo applications. PLNPs were well dispersed in water with hydrodynamic radii of 5 nm and emitted strong persistent luminescence at 696 nm upon the irradiation of UV light. The advantage of afterglow imaging over fluorescent imaging of PLNPs was first established after subcutaneous injection to mice with much higher contrast and less interference of autofluorescence. PLNPs quickly migrated to sentinel lymph nodes after the interdermal injection to extremity of mice. The tumor drainage lymph node imaging was achieved within 5 min upon the intratumoral injection to H460 tumor bearing mice and the signal to noise ratio was 462. Due to the lack of targeting moieties, the intravenous injected PLNPs mainly accumulated in liver. There were no statistical changes in serum biochemistry and abnormal histopathological characteristic, indicating the low toxicity of PLNPs. These findings highlighted the great potential of PLNPs as high-performance imaging reagent for lymph node identification.

Discovery of a novel covalent CDK4/6 inhibitor based on palbociclib scaffold.

Cyclin-dependent kinases 4 and 6 (CDK4/6), which are involved in dynamic regulation of cell cycle, play an indispensable role in controlling the tumor growth. Here, based on the scaffold of palbociclib, we designed and synthesized a series of covalent CDK4/6 inhibitors that targeted amino acid Thr107. The optimized compound C-13 exhibited potent in vitro anticancer activity against CDK4/6 with high selectivity over CDK4/6. Moreover, C-13 showed significant tumor growth inhibition in MDA-MB-231 tumor xenograft model (TGI of 93.49% at dose of 40 mg/kg) without causing significant weight loss and toxicity during the treatment period.

Targeting Cysteine Located Outside the Active Site: An Effective Strategy for Covalent ALKi Design.

Potent inhibitors of ALK are highly desired because of the occurrence of drug resistance. We herein firstly report the development of a rationally designed inhibitor, Con B-1, which can covalently bind to Cys1259, a cysteine located outside the ALK active site by linking a warhead with Ceritinib through a 2,2'-Oxybis(ethylamine) linker. The in vitro and in vivo assays showed ConB-1 is a potent selective ALKi with low toxicity to normal cells. In addition, the molecule showed significant improvement of anticancer activities and potential antidrug resistant activity compared with Ceritinib, demonstrating the covalent inhibitor of ALK can be a promising drug candidate for the treatment of NSCLC. This work may provide a novel perspective on the design of covalent inhibitors.

Discovery of a PROTAC targeting ALK with in vivo activity.

Anaplastic lymphoma kinase (ALK) was involved in the development of various cancer types. Although several ALK inhibitors have been advanced to clinical trials, the emergence of drug resistance has limited the clinical application of them. To overcome the drug resistance, proteolysis targeting chimeras (PROTACs) could be an alternative strategy. In this study, a series of ALK degraders were designed and synthesized. The degraders were developed through the conjugation of LDK378 and CRBN E3 ubiquitin ligase ligands. Among all the molecules, compound B3 showed potent selective inhibitory activity to ALK and can decrease the cellular levels of ALK fusion proteins in a concentration- and time-dependent manner in H3122 cell line. Meanwhile, B3 showed improved anticancer activity in vitro comparing with LDK378 and the antiproliferative activity to xenograft tumor model was acceptable. All the results demonstrated that ALK degrader B3 with in vitro and in vivo anti-cancer activities was valuable for further investigation.

Toxicity and photosynthetic inhibition of metal-organic framework MOF-199 to pea seedlings.

Metal-organic framework (MOF) materials are star materials with unique structures and properties. To ensure safe production and applications, the toxicity and environmental hazards of MOF materials should be thoroughly investigated. However, the environmental impact of MOF materials on plants is completely unknown. Herein, we reported the toxicity and photosynthetic inhibitory properties of MOF-199 to pea plants (Pisum sativum L.). MOF-199 was synthesized by hydrothermal method. MOF-199 was copper containing double-pyramid of high surface area (668 m2/g). MOF-199 accelerated the germination of pea seeds, but the total germination rates were unchanged. MOF-199 inhibited the seedling growth at high concentrations. The net photosynthetic rate increased, while the total photosynthesis capability decreased. Damage to the acceptor side of photosystem II was evidenced by chlorophyll fluorescence. Mechanistically, MOF-199 released Cu2+ in the nutrient solution, led to Cu2+ accumulations in seedlings, and promoted oxidative stress. In addition, the photosynthetic inhibitions of MOF-199 were stronger than equivalent concentrations of Cu(NO3)2, implying that MOF-199 particles also contributed to the environmental hazards. Our results highlighted the potential threat of MOF materials to plant growth and photosynthesis.

Discovery of 4-(3,5-dimethoxy-4-(((4-methoxyphenethyl)amino)methyl)phenoxy)-N-phenylaniline as a novel c-myc inhibitor against colorectal cancer in vitro and in vivo.

Proto-oncogene c-Myc plays an essential role in the development of colorectal cancer (CRC), since downregulation of c-Myc inhibits intestinal polyposis, which is the most cardinal pathological change in the development of CRC. Herein, a series of novel phenoxy-N-phenylaniline derivatives were designed and synthesized. The cytotoxicity activities of all the derivatives were measured by MTT assay in different colon cancer cells, 4-(3,5-dimethoxy-4-(((4-methoxyphenethyl)amino)methyl)phenoxy)-N-phenylaniline (42) was discovered, the lead compound 42 with excellent cytotoxicity activity of IC50 = 0.32 µM, IC50 = 0.51 µM, in HT29 and HCT 15 cells, respectively. Compound 42 had a good inhibitory activity of c-Myc/MAX dimerization and DNA binding. Besides, compound 42 could effectively induce apoptosis and induced G2/M arrest in low concentration and G0/G1 arrest in high concentration to prevent the proliferation and differentiation in colon cancer cells. Western blot analysis confirmed the 42 strongly down-regulated expression of c-Myc. Furthermore, during 30 days treatment 42 exhibited excellent efficacy in HT29 tumor xenograft model without causing significant weight loss and toxicity. Consequently, 42 could be a promising drug candidate for CRC therapy.

Fast Identification and Quantification of Graphene Oxide in Aqueous Environment by Raman Spectroscopy.

Today, graphene nanomaterials are produced on a large-scale and applied in various areas. The toxicity and hazards of graphene materials have aroused great concerns, in which the detection and quantification of graphene are essential for environmental risk evaluations. In this study, we developed a fast identification and quantification method for graphene oxide (GO) in aqueous environments using Raman spectroscopy. GO was chemically reduced by hydrazine hydrate to form partially reduced GO (PRGO), where the fluorescence from GO was largely reduced, and the Raman signals (G band and D band) were dominating. According to the Raman characteristics, GO was easily be distinguished from other carbon nanomaterials in aqueous environments, such as carbon nanotubes, fullerene and carbon nanoparticles. The GO concentration was quantified in the range of 0.001-0.6 mg/mL with good linearity. Using our technique, we did not find any GO in local water samples. The transport of GO dispersion in quartz sands was successfully quantified. Our results indicated that GO was conveniently quantified by Raman spectroscopy after partial reduction. The potential applications of our technique in the environmental risk evaluations of graphene materials are discussed further.

Discovery of 4-phenyl-2H-benzo[b][1,4]oxazin-3(4H)-one derivatives as potent and orally active PI3K/mTOR dual inhibitors.

PI3K/Akt/mTOR signaling pathway plays an important role in cancer cell growth and survival. In this study, a new class of molecules with skeleton of 4-phenyl-2H-benzo[b] [1,4]oxazin-3(4H)-one were designed and synthesized targeting this pathway. Bioassays showed that, among all the molecules, 8d-1 was a pan-class I PI3K/mTOR inhibitor with an IC50 of 0.63 nM against PI3Kα. In a wide panel of protein kinases assays, no off-target interactions of 8d-1 were identified. 8d-1 was orally available, and displayed favorable pharmacokinetic parameters in mice (oral bioavailability of 24.1%). In addition, 8d-1 demonstrated significant efficiency in Hela/A549 tumor xenograft models (TGI of 87.7% at dose of 50 mg/kg in Hela model) without causing significant weight loss and toxicity during 30 days treatment. Based on the bioassays, compound 8d-1 could be used as an anti-cancer drug candidate.

Synthesis and biological evaluation of 3-(1,3,4-oxadiazol-2-yl)-1,8-naphthyridin-4(1H)-ones as cisplatin sensitizers.

A series of novel 3-(1,3,4-oxadiazol-2-yl)-1,8-naphthyridin-4(1H)-one derivatives were synthesized and their anti-cancer as well as cisplatin sensitization activities were evaluated. Among them, compounds 6e and 6h exhibited significant cisplatin sensitization activity against HCT116. Hoechst staining and annexin V-FITC/PI dual-labeling studies demonstrated that the combination of 6e/6h and cisplatin can induce tumour cell apoptosis. Western blot showed that the expression of ATR downstream protein, CHK1, decreased in 6e + cisplatin and 6h + cisplatin groups compared with that in the test compound and cisplatin group. Furthermore, docking of 6e/6h into the ATR structure active site revealed that the N1 and N8 atoms in the naphthyridine ring and the hybrid atom in the oxadiazole ring are involved in hydrogen bonding with Val170, Glu168 and Tyr155. Additionally, the naphthyridine ring is also involved in π-π stacking with Trp169. Accordingly, compounds 6e and 6h can be expected to be potential cisplatin sensitizers that can participate in HCT116 cancer therapy.

Pharmacophore-based virtual screening, molecular docking, molecular dynamics simulation, and biological evaluation for the discovery of novel BRD4 inhibitors.

Bromodomain is a recognition module in the signal transduction of acetylated histone. BRD4, one of the bromodomain members, is emerging as an attractive therapeutic target for several types of cancer. Therefore, in this study, an attempt has been made to screen compounds from an integrated database containing 5.5 million compounds for BRD4 inhibitors using pharmacophore-based virtual screening, molecular docking, and molecular dynamics simulations. As a result, two molecules of twelve hits were found to be active in bioactivity tests. Among the molecules, compound 5 exhibited potent anticancer activity, and the IC50 values against human cancer cell lines MV4-11, A375, and HeLa were 4.2, 7.1, and 11.6 µm, respectively. After that, colony formation assay, cell cycle, apoptosis analysis, wound-healing migration assay, and Western blotting were carried out to learn the bioactivity of compound 5.