UNASSIGNED: To investigate the toxicity of combretastatin A4 phosphate (CA4P) hyaluronic acid (HA) gel nanoparticles (HA-CA4P-NPs) in OSCC (oral squamous cell carcinoma).
UNASSIGNED: Toxicity was investigated using fluorescence microscopy, MTT assay, flow cytometry, and OSCC xenograft mouse models.
UNASSIGNED: Compared with CA4P, HA-CA4P-NPs generated nearly 10 times more fluorescence in OSCC cells. Cytotoxicity assays showed that HACA4P-NPs were more toxic to SCC-4 cells but not to HNECs. Remarkable necrosis was induced in SCC-4 cells after exposure to HA-CA4P-NPs, and related proteins were upregulated. Furthermore, HA-CA4P-NPs significantly reduced the tumour size.
UNASSIGNED: HA-CA4P-NPs improved drug release and delivery, and increased cytotoxicity to cancer cells.

Proteolysis-targeting chimaera (PROTAC) has received extensive attention in industry. However, there are still some limitations that hinder its further development. In a previous study, our group first demonstrated that the HSP90 degrader BP3 synthesised by the principle of PROTACs showed therapeutic potential for cancer. However, its application was hindered by its high molecular weight and water insolubility. Herein, we aimed to improve these properties of HSP90-PROTAC BP3 by encapsulating it into human serum albumin nanoparticles (BP3@HSA NPs). The results demonstrated that BP3@HSA NPs showed a uniform spherical shape with a size of 141.01 ± 1.07 nm and polydispersity index < 0.2; moreover, BP3@HSA NPs were more readily taken up by breast cancer cells and had a stronger inhibitory effect in vitro than free BP3. BP3@HSA NPs also demonstrated the ability to degrade HSP90. Mechanistically, the improved inhibitory effect of BP3@HSA NPs on breast cancer cells was related to its stronger ability to induce cell cycle arrest and apoptosis. Furthermore, BP3@HSA NPs improved PK properties and showed stronger tumour suppression in mice. Taken together, this study demonstrated that hydrophobic HSP90-PROTAC BP3 nanoparticles encapsulated by human serum albumin could improve the safety and antitumour efficacy of BP3.

The colchicine binding site of tubulin is a promising target for discovering novel antitumour agents. Previously, we identified 2-aryl-4-amide-quinoline derivatives displayed moderate tubulin polymerisation inhibitory activity and broad-spectrum in vitro antitumour activity. In this study, structure based rational design and systematic structural optimisation were performed to obtain analogues C1∼J2 bearing diverse substituents and scaffolds. Among them, analogue G13 bearing a hydroxymethyl group displayed good tubulin polymerisation inhibitory activity (IC50  =  13.5 μM) and potent antiproliferative activity (IC50 values: 0.65 μM∼0.90 μM). G13 potently inhibited the migration and invasion of MDA-MB-231 cells, and displayed potent antiangiogenic activity. It efficiently increased intracellular ROS level and decreased MMP in cancer cells, and obviously induced the fragmentation and disassembly of the microtubules network. More importantly, G13 exhibited good in vivo antitumour efficacy in MDA-MB-231 xenograft model (TGI  =  38.2%; i.p., 30 mg/kg).

Based on the previous synthesis of tetracyclic and tricyclic benzimidazoles starting from 1,4:3,6-dianhydro-d-fructose and o-phenylenediamines, a series of 5(6)-amino substituted tetracyclic and tricyclic benzimidazolequinones were obtained through the oxidation of 4,7-dimethoxy-benzimidazole analogues with bis(trifluoroacetoxy)iodobenzene (PIFA) and subsequent substitution with various aliphatic and aromatic amines. Biological evaluations of the target benzimidazolequinones indicated that all the arylamino-substituted benzimidazolequinones possess potent antitumour activity against human gastric cancer cells (MGC-803), especially compound a21-2. Furthermore, compound a21-2 inhibits gastric cancer cells proliferation and cell colony formation. Mechanistic investigations showed that compound a21-2 induces ROS production, which subsequently causes DNA damage and activation of ATM/Chk2, leading to G2/M phase arrest. ROS activates the c-Jun N-terminal kinase (JNK) pathway to induce mitochondrial-mediated apoptosis. In vivo studies showed that compound a21-2 inhibits the growth of tumours in nude mice without significant systemic toxicity. These findings suggest that compound a21-2 represents a promising candidate antitumour drug.

The medicinal fungus Sanghuangporus vaninii can be cultivated in large scale and has outstanding antitumour activity. In this study, water-soluble S. vaninii polysaccharides (SVPs) were extracted from fruiting bodies. Four polysaccharide sub-fractions (SVP-W, SVP-1, SVP-2 and SVP-3) were isolated, with molecular weights from 90.50 kDa to 261.70 kDa, and all inhibited the proliferation of non-small cell lung cancer cell lines A549, 95-D and NCI-H460, especially the acidic SVP-1. SVP-1 affected cell morphology and colony formation in NCI-H460 cells. It also promoted cell apoptosis following nuclear fluorescence staining and flow cytometry. Methylation and nuclear magnetic resonance analyses revealed that SVP-1 is a heteroglycan with the main chain →4)-β-D-Glcp-(1 → 6)-β-D-Glcp-(1 → 6)-α-D-Galp-(1 → 6)-β-D-Glcp-(1→, and the branched chain α-D-Manp-(1 → 2)-α-D-Manp-(1 → 3)-β-D-Glcp-(1 → 3,6)-β-D-Glcp-(1→. The findings indicate that this natural acidic polysaccharide has potential for non-small cell lung cancer therapy.

A series of novel α-l-threose nucleoside phosphonate analogs, 4(R)-methyl-3-O-phosphonomethyl-α-l-threose nucleosides, were synthesized in multistep sequences starting from d-xylose. The synthetic sequence consisted of the following key stages: (i) the multistep synthesis of 1,2-O-isopropylidenyl-4(R)-methyl-3-O-phosphonomethyl-l-threose, (ii) the transformation of 1,2-O-isopropylidenyl sugar into suitable 1,2-di-O-acyl l-threose precursor, and (iii) the construction of target α-l-threose nucleoside phosphonate analogs by Vorbrüggen glycosidation reaction, deprotection of acyl group, and hydrolysis of diethyl group on phosphonate. The target nucleoside phosphonates were evaluated for their antitumour activities in cell culture-based assays. Compound 8g, 2-fluroadenosine phosphonate, showed remarkable activity against human breast cancer cell lines (MCF-7 and MDA-MB-231) with IC50 values of 0.476 and 0.391 μM, corresponding to 41- and 47-fold higher potency than the reference compound 5-FU, respectively. Subsequent investigations found that the compound 8g can inhibit the proliferation of breast cancer cells and cell cloning. The mechanistic studies indicated that compound 8g could cause DNA damage to breast cancer cells through the ATM-Chk1/Chk2-cdc25c pathway, leading to blockage of the G2/M phase cycle of breast cancer cells, which ultimately led to apoptosis. Moreover, 8g could inhibit the PI3K/AKT signaling pathway and induce apoptosis. These results indicate that compound 8g holds promising potential as an antitumour agent.

To explore novel antitumor agents with high efficiency and low toxicity, riluzole alkyl derivatives (4a-4i) were synthesized. Their anti-proliferative activities against HeLa, HepG2, SP2/0, and MCF-7 cancer cell lines were assessed by the CCK-8 assay and compared with human normal liver (LO2) cells. Most of them showed potent cytotoxic effects against four human tumor cell lines and low toxic to LO2 cells. In particular, 2-(N-ethylamine)-6-trifluoromethoxy- benzothiazole (4a) showed a IC50 value of 7.76 μmol/L in HeLa cells and was found to be nontoxic to LO2 cells up to 65 μmol/L. Furthermore, flow cytometry indicated that 4a could induce remarkable early apoptosis and G2/M cell cycle arrest in HeLa cells. It also impaired the migration ability of HeLa cells in wound healing assays. Western blot results demonstrated that 4a suppressed Bcl-2 protein expression but increased the level of Bax in HeLa cells, and elevated the Bax/Bcl-2 expression ratio. These new findings suggest that 4a exhibited beneficially anti-cervical cancer effect on HeLa cells by inducing HeLa cell apoptosis.

Specific inhibition of CDK9 is considered a promising strategy for developing effective anticancer therapeutics. However, most of the reported CDK9 inhibitors are still at an early stage of development and lack selectivity against other CDKs. Herein, we discovered coumarin derivative 30i as a potent CDK9 inhibitor with high selectivity (8300-fold over CDK7). Binding mode analysis illustrated that the substituent coumarin moiety is a critical group for CDK9 selectivity by occupying a flexible hinge/αD region, which is sterically hindered in other CDKs. Compound 30i showed excellent cellular antiproliferative activity, moderate pharmacokinetic property and low hERG inhibition. Moreover, 30i significantly induced tumour growth inhibition in a dose-dependent manner without causing an obvious loss of body weight in an MV4-11 xenograft mice model. Altogether, these results suggest that 30i may serve as a potential acute myeloid leukaemia (AML) therapeutics by selectively targeting CDK9.

Colorectal cancer is one of the leading causes of cancer-related death in elderly people. The natural product muricatacin is an important member of the γ-lactone family, and it has exhibited antitumour activity in multiple cancer cell lines; however, the antitumour activities of muricatacin stereoisomers and their derivatives in colorectal cancer cells have not yet been systematically explored.
The colorectal carcinoma cell line HCT116 was investigated in this study. Cell proliferation was assessed by MTT assay or crystal violet staining. Cell cycle arrest and cell apoptosis were evaluated by flow cytometry assay. The expression levels of p53, p21, cyclin E, cyclin D1, caspase-3, cleaved caspase-3, caspase-9, cleaved caspase-9 and LC3B were measured using western blot analysis. Autophagy induced by M2 was monitored by immunofluorescence assay with an antibody against LC3B.
Cell proliferation assays showed that both naturally occurring muricatacin (M4) and its synthetic stereoisomer (M2) are potent cell growth inhibitors in HCT116 cells, with IC50 values of 79.43 and 83.17μM, respectively; these values are much lower than those of the other two isomers, M1 and M3, and those of the sixmembered lactone analogues. The flow cytometry analysis revealed that M2 and M4 induced significant cell cycle arrest during G0/G1 phase and caused relatively low apoptosis rates in HCT116 cells. Further analysis indicated that M2 caused p53-independent p21 induction and cyclin E/cyclin D1 downregulation. In addition, M2 also markedly induced autophagy in the early stage of administration.
Our results suggested that muricatacins possess potent antitumour activity against the colorectal carcinoma cell line HCT116 through inducing G0/G1 phase cell cycle arrest and autophagy in the early stage of administration.

A novel series of methyl indolinone-6-carboxylates bearing an indole moiety were identified as potent angiokinase inhibitors. The most active compound, A8, potently targeted the kinase activities of vascular endothelial growth factor receptors 2 and 3, and platelet-derived growth factor receptors α and β, with IC50 values in the nanomolar range. In addition, A8 effectively suppressed the proliferation of human umbilical vein endothelial cells, and HT-29 and MCF-7 cancer cells, by inducing apoptosis. Compound A8 is thus a promising candidate for further investigation.