Hydrazide-hydrazones as Small Molecule Tropomyosin Receptor Kina se A (TRKA) Inhibitors: Synthesis, Anticancer Activities, In silico ADME and Molecular Docking Studies.

AIM: The aim of the study was to search for new anticancer agents as TRKA inhibitors. BACKGROUND: A series of new salicylic acid hydrazide hydrazones were synthesized and evaluated for their in vitro anticancer activities against lung (A549), ovarian (SK-OV-3), skin (SK-MEL-2), and colon (HCT15) cancer cell lines, and tropomyosin receptor kinase A (TRKA) inhibitory activities. OBJECTIVE: In this study, we focused on the synthesis and anticancer properties evaluation of salicylic acid hydrazide hydrazones as TRKA inhibitors. The in vitro anticancer activities of hydrazone analogs were measured against four cancer cell lines, and the TRKA inhibitory properties were investigated using an enzyme assay to determine their modes of action. In silico molecular docking was conducted using the crystal structure of the TRKA receptor to study the interactions and modes of binding at its active site, and ligand-based target predictions were used to identify putative secondary enzymatic targets of the synthesized compounds. Additionally, pharmacokinetic properties, toxicity effects, and drug scores of the studied molecules were also assessed. METHODS: A series of hydrazide hydrazones were prepared by means of a facile and straight-forward two-step reaction under soft reflux conditions from a methyl ester of substituted aromatic acids and hydrazine hydrate followed by the condensation with substituted aldehydes. In vitro cytotoxic properties of the synthesized compounds were screened against four human cancer cells using the SRB (sulforhodamine-B) colorimetric method. The TRKA inhibitory activity was measured by enzymatic assay. In silico ADME, drug score properties, docking studies, and ligand-based target prediction analyses were performed using Osiris Cheminformatics and AutoDock Vina, and SwissTargetPrediction bioinformatics software. RESULTS: In vitro bioassays revealed that compound 6 exhibited the most potent broad-spectrum anticancer activities with IC50 values of 0.144, <0.001, 0.019, and 0.022 µM against A549, SK-OV-3, SK-MEL-2, and HCT15 cancer cells, respectively, followed by compounds 11, 3a, and 9. In TRKA inhibitory assays, compounds 3e and 11 demonstrated the highest potency with IC50 values of 111 and 614 nM, respectively. The results of docking studies on 3e and 11 with the active site of the TRKA receptor revealed that both compounds interacted as previously reported TRKA inhibitors with high docking scores. CONCLUSION: New salicylic acid hydrazide hydrazones were synthesized, and the most active compounds exhibited significant anticancer properties against A549, SK-OV-3, SK-MEL-2, and HCT15 cancer cells, suggesting to be good candidates for in vivo studies. The results obtained in the present study would help in the design and preparation of new hydrazidehydrazone analogs as potential TRKA inhibitors for cancer treatment.

A novel tropomyosin-related kinase A inhibitor, KK5101 to treat pancreatic cancer.

Tropomyosin-related kinase A (TrkA) plays important roles in tumor cell growth and survival signaling and contributes to chemo-resistance in pancreatic cancer. Therefore, we developed KK5101, a novel TrkA target inhibitor and assessed its anti-cancer effects and investigated underlying mechanism of action in pancreatic cancer. KK5101 was characterized to inhibit TrkA selectively and potently by protein binding assay. It effectively inhibited the growth and proliferation of pancreatic cancer cells. Also, KK5101 increased apoptosis with loss of mitochondrial membrane potential, as evidenced by increases of cytochrome c releases. It increased numbers of TUNEL-positive apoptotic cells, and cell death including early and late apoptosis by Annexin V assay. In addition, activation of the TrkA signaling cascades including p-AKT, p-MEK, and p-STAT3 were inhibited by KK5101 treatment in vitro, as well as ex vivo tumor spheroid models, resulting in potent induction of apoptosis. Importantly, KK5101 also significantly attenuated tumor growth of in vivo pancreatic cancer models. These findings indicate that KK5101 may exert antitumor effects by directly affecting cancer cell growth or survival via inhibition of TrkA signaling pathway. We therefore suggest that KK5101 is a novel therapeutic candidate for treating pancreatic cancer.

Nerve growth factor induced after temporomandibular joint inflammation decelerates chondrocyte differentiation.

OBJECTIVE: The goal of this study was to investigate changes in nerve growth factor (NGF) and its high-affinity receptor-tropomyosin receptor kinase A (TrkA) expression in the TMJ after intra-articular inflammation. MATERIALS AND METHODS: We employed the Col1-IL1ß(XAT) inducible model of joint inflammation. Changes in NGF and TrkA expression were evaluated by immunohistochemistry. The function of NGF on cell differentiation was assessed in vitro employing the ATDC5 chondrocyte cell line. RESULTS: NGF expression was observed in articular chondrocytes only after TMJ inflammation, whereas TrkA expression was detected in articular chondrocytes under both naïve as well as inflamed conditions. The potential effect of NGF on articular chondrocytes was studied on the ATDC5 cell line, whereby NGF decelerated the maturation rate of this chondrogenic cell line, presumably by arresting cell differentiation at the prehypertrophic stage of chondrocyte maturation. CONCLUSIONS: NGF-TrkA signaling in the TMJ provides potentially a means of protection against the development of osteoarthritis by decelerating chondrocyte differentiation. This discovery may lead to the development of novel therapies for osteoarthritis of the TMJ and other joints.

Effects of TrkA inhibitory peptide on cancer-induced pain in a mouse melanoma model.

PURPOSE: Tropomyosin receptor kinase (Trk) A, a high-affinity receptor of nerve growth factor, is a therapeutic target for both noxious and neuropathic pain. The present study examined the effects of an inhibitory peptide of Trk activity (IPTRK) 3 that inhibits TrkA activity on cancer-induced pain in a mouse melanoma model. METHODS: The hind paws of mice were inoculated with B16-F1 mouse melanoma cells on day 0. We administered IPTRK3 (20 mg/kg i.p.) repetitively on days 5, 6, 7, 8, and 9, and evaluated pain-related behaviors on days 0, 5, 10, 15, and 20 after tumor inoculation. RESULTS: Following inoculation, mice demonstrated mechanical allodynia and thermal hyperalgesia with an increased number of flinches, and paw volume increased gradually. However, an intraperitoneal injection of IPTRK3 significantly inhibited mechanical allodynia on day 15 and suppressed the number of flinches on day 20. The increased paw volume was significantly suppressed on day 20 after tumor inoculation. IPTRK3, however, showed no significant effect on thermal hyperalgesia. CONCLUSIONS: These results suggest that TrkA inhibitory peptide likely suppress melanoma-induced pain with concomitant reduction in the increased paw volume in a mouse skin cancer pain model.