Chemical Approach to Positional Isomers of Glucose-Platinum Conjugates Reveals Specific Cancer Targeting through Glucose-Transporter-Mediated Uptake in Vitro and in Vivo

Molecular Tools for Facilitative Carbohydrate Transporters (Gluts)

Facilitative carbohydrate transporters-Gluts-have received wide attention over decades due to their essential role in nutrient uptake and links with various metabolic disorders, including diabetes, obesity, and cancer. Endeavors directed towards understanding the mechanisms of Glut-mediated nutrient uptake have resulted in a multidisciplinary research field spanning protein chemistry, chemical biology, organic synthesis, crystallography, and biomolecular modeling. Gluts became attractive targets for cancer research and medicinal chemistry, leading to the development of new approaches to cancer diagnostics and providing avenues for cancer-targeting therapeutics. In this review, the current state of knowledge of the molecular interactions behind Glut-mediated sugar uptake, Glut-targeting probes, therapeutics, and inhibitors are discussed.

Glycosylated Platinum(IV) Complexes as Substrates for Glucose Transporters (GLUTs) and Organic Cation Transporters (OCTs) Exhibited Cancer Targeting and Human Serum Albumin Binding Properties for Drug Delivery

Glycosylated platinum(IV) complexes were synthesized as substrates for GLUTs and OCTs for the first time, and the cytotoxicity and detailed mechanism were determined in vitro and in vivo. Galactoside Pt(IV), glucoside Pt(IV), and mannoside Pt(IV) were highly cytotoxic and showed specific cancer-targeting properties in vitro and in vivo. Glycosylated platinum(IV) complexes 5, 6, 7, and 8 (IC₅₀ 0.24-3.97 μM) had better antitumor activity of nearly 166-fold higher than the positive controls cisplatin (1a), oxaliplatin (3a), and satraplatin (5a). The presence of a hexadecanoic chain allowed binding with human serum albumin (HSA) for drug delivery, which not only enhanced the stability of the inert platinum(IV) prodrugs but also decreased their reduction by reductants present in human whole blood. Their preferential accumulation in cancer cells compared to noncancerous cells (293T and 3T3 cells) suggested that they were potentially safe for clinical therapeutic use.

Synthesis, Biological Evaluation, and Molecular Docking Studies on the DNA Binding Interactions of Platinum(II) Rollover Complexes Containing Phosphorus Donor Ligands

Cyclometalated rollover complexes of the type [PtMe(κ² N,C-bipyO-H)(L)] [bipyO-H=cyclometalated 2,2'-bipyridine N-oxide; L=tricyclohexylphosphine (PCy₃ , 2 a), 2-(diphenylphosphino)pyridine (PPh₂ py, 2 b), P(OPh)₃ (2 c)] were synthesized by treating [PtMe(κ² N,C-bipyO-H)(SMe₂ )] (1) with various monodentate phosphine and phosphite ligands. These complexes were characterized by NMR spectroscopy, and the structure of 2 a was confirmed by single-crystal X-ray diffraction. Complex 1 was treated with bis(diphenylphosphino)methane (dppm) at a 1:1 ratio to give the corresponding [PtMe(κ² N,C-bipyO-H)(κ¹ P-dppm)] (3 b) complex, in which the dppm ligand acts as a monodentate pendant ligand. The biological activities of these complexes were evaluated against a panel of four standard cancer cell lines: lung carcinoma (A549), ovarian carcinoma (OV-90 and SKOV3), and breast carcinoma (MCF-7). Complexes 2 c and especially 3 b indicated effective potent cytotoxic activity regarding the cell lines. Electrophoresis mobility shift assays and molecular-modeling investigations were performed to determine the specific binding mode and the binding orientation of these alkylating agents to DNA. Detection of cellular reactive oxygen species was also determined.

Mono-functionalized glycosylated platinum(IV) complexes possessed both pH and redox dual-responsive properties: Exhibited enhanced safety and preferentially accumulated in cancer cells in vitro and in vivo

A serious of carbohydrate-conjugated platinum(IV) complexes in the form Pt(L2)(A2)(OH)R based on the clinical drug cisplatin and oxaliplatin were designed, synthesized and evaluated as antitumor agents in vitro and in vivo. The conjugates possessing both pH and redox dual-responsive properties exhibited more potent cytotoxicity in seven different human cancer cell lines and lower toxicity to the normal 3T3 cells than cisplatin, oxaliplatin and even the reported bis-functionalized glycosylated platinum(IV) complexes indicating the enhanced safety of the sugar conjugates. Cellular drug uptake and DNA platination were also superior to cisplatin, oxaliplatin and the reported bis-functionalized ones. Peak current of B7 and B8 with the scan rate of 200mv/s at the concentration of 0.08 mM was 5-fold higher at pH 6.4 than the pH 7.4, indicating that carbohydrate-conjugated mono-functionalized platinum(IV) complexes possessed both pH and redox dual-responsive properties in the cancer cells. The in vivo assays demonstrated that the Pt(IV) compounds could inhibit the growth of MCF-7 tumour and exert more safety than oxaliplatin.

Synthesis, Binding Properties, and Differences in Cell Uptake of G-Quadruplex Ligands Based on Carbohydrate Naphthalene Diimide Conjugates

The G-quadruplexes (G4s) are currently being explored as therapeutic targets in cancer and other pathologies. Six carbohydrate naphthalene diimide conjugates (carb-NDIs) have been synthesized as G4 ligands to investigate their potential selectivity in G4 binding and cell penetration. Carb-NDIs have shown certain selectivity for G4 structures against DNA duplexes, but different sugar moieties do not induce a preference for a specific G4 topology. Interestingly, when monosaccharides were attached through a short ethylene linker to the NDI scaffold, their cellular uptake was two- to threefold more efficient than that when the sugar was directly attached through its anomeric position. Moreover, a correlation between more efficient cell uptake of these carb-NDIs and their higher toxicity in cancerous cell lines has been observed. Carb-NDIs seem to be mainly translocated into cancer cells through glucose transporters (GLUT), of which GLUT4 plays a major role.

A survey of the mechanisms of action of anticancer transition metal complexes

Metal complexes have been the subject of numerous investigations in oncology but, despite the plethora of newly synthesized compounds, their precise mechanisms of action remain generally unknown or, for the best, incompletely determined. The continuous development of efficient and sensitive techniques in analytical chemistry and molecular biology gives scientists new tools to gather information on how metal complexes can be effective toward cancer. This review focuses on recent findings about the anticancer mechanism of action of metal complexes and how the ligands can be used to tune their pharmacological and physicochemical properties.

Total synthesis, structural elucidation and anti-inflammatory activity evaluation of 2-deoxy-3,6-anhydro hexofuranoside derivatives isolated from Sauropus rostratus

The first total synthesis of four 2-deoxy-3,6-anhydro hexofuranoside derivatives isolated from Genus Sauropus rostratus was accomplished.