Abstract
Objective(s):
Osteosarcoma is a major solid malignant tumor of bone, possessing significant burden on healthcare due to non-availability of specific anticancer agents. The current study was conducted to identify novel 1,3,5-triazine derivatives against osteosarcoma.
Materials and Methods:
The compounds were synthesized in a straight-forward two-step reaction and subsequently tested against PI3K and mTOR kinase and anticancer activity against osteosarcoma cells (MG-63, U2-OS, and Saos-2). The effect of the most potent compound was evaluated on apoptosis and cell phase of Saos-2 cells. The pharmacological activity was further established in the patient-derived orthotopic xenograft (PDOX) mouse model.
Results:
The developed compounds 8 (a-f) showed significant inhibitory activities against PI3K, mTOR, and OS cells. Among the tested series, compound 8a showed highly potent PI3K/mTOR inhibitory activity with significant anticancer activity against Saos-2 cells compared with Imatinib as standard. It also induces apoptosis and causes G2/M arrest in Saos-2 cells. Compound 8a significantly improved body weight, reduced tumor volume, and inhibited lung metastasis in athymic nude mice in a PDOX mouse model. It also showed optimal pharmacokinetic parameters in SD rats.
Conclusion:
In summary, 1,3,5-triazine analogs were identified as new PI3K/mTOR inhibitors against osteosarcoma.
Key Words: 1, 3, 5-triazine, Apoptosis, mTOR, Osteosarcoma, PI3K
Introduction
Cancer is the most dreadful disease ever known to humankind. Despite various advances in therapeutics and diagnostics, still, the management of cancer is troublesome (1). Among the types of cancer affecting humans, osteosarcoma is the most common solid malignant tumor of bones (2, 3). Despite advances in chemotherapy, prognosis and survivability of patients are not very encouraging. Various studies suggested that in the past 40 years, the overall survivability of non-metastatic osteosarcoma patients remained sluggish (4).Thus Thus, the development of novel targeted therapies is urgently needed to fill the void.
Imatinib mesylate (Gleevec) is a potent tyrosine kinase anticancer molecule widely used against bcr-abl-positive chronic myeloid leukemia (5-7). Additionally, it showed a significant effect on the bone cells where it targets MCF receptors and induces apoptosis of mature osteoblast (8). Imatinib significantly inhibited the proliferation of osteosarcoma cells by arresting cell-cycle and provoking caspase-dependent apoptosis (9-11). The above studies showed the significant potential of Imatinib against osteosarcoma.
Studies have found that phosphatidylinositol-3-kinase (PI3K)/Akt and the mammalian target of rapamycin (mTOR) are aberrantly activated in osteosarcoma (12). This pathway is critically involved in cell proliferation, growth, cell size, metabolism, and motility. Drugs such as Duvelisib, Copanlisib, and Idelalisib showed potent inhibition of the PI3K/mTOR pathway and were approved clinically against many tumors, including osteosarcoma (13). Thus, discovery of new drugs to inhibit or modulate PI3K/mTOR offers superior benefits against osteocarcinoma.
Almost 80 % of inhibitors used in the treatment of cancers belong to the class of heterocyclic small molecules (14). These molecules are very highly sought over others because of ease of synthesis, intrinsic versatility, and unique physicochemical properties that can be fine-tuned in the light of biological activity, toxicity, and pharmacokinetic activity to obtain molecularly targeted agents. 1,3,5-triazine, a highly active pharmacophore showed a diverse array of biological activity against disease-causing pathogenic organisms, such as bacteria (15–20), fungus (21–23)malaria (24–29), HIV (30), HIV (30), diabetes (15), and cystic fibrosis (31). Much of the work has also been documented on the discovery of anticancer agents from 1,3,5-triazine scaffold (32). It inhibits numerous kinases for anticancer activity, for instance, Cyclin-dependent kinase (CDK)(33), epidermal growth factor receptor tyrosine kinase (EGFR-TK) (34), and phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin (PI3K/Akt/mTOR)(35, 36). Moreover, various 1,3,5-triazines were proven as effective antileukemic agents (37). In our previous study, we developed a novel series of 1,3,5-triazine nicotinohydrazide as potent osteosarcoma agents via inhibition of CDK (38). Therefore, in continuation of our anti-osteosarcoma research program, the present study enumerates the anti-osteosarcoma activity of 1,3,5-triazine analogs inspired by Imatinib and elucidation of its mechanism of action (Figure 1). We have also determined the effect of our designed compound on lung metastases of osteosarcoma because patients affected by osteosarcoma present poor prognosis due to lung metastasis of the disease (39).
Figure 1.

Design of target compounds inspired by Imatinib
Materials and Methods
Chemistry
The molecules were synthesized as per the earlier reported procedure and they were characterized with the help of melting point which is found in agreement with the earlier reported melting points (40).
PI3K and mTOR kinase inhibition assay
The inhibitory activity of developed molecules against PI3K and mTOR was identified using luminescent kinase assay, and Lance Ultra assay from Promega, USA, respectively as per our earlier reported procedure (38).
Pharmacological activity
Cells
The human osteosarcoma cancer cell lines MG-63, U2-OS, and Saos-2 were purchased from CBSIBCB of the Chinese Academy of Sciences (Shanghai, China)
Cellular antiproliferation assay using cell counting kit (CCK-8)
The CCK-8 assay was used in the current study to analyze the effect of compounds on cellular proliferation. The transfected cells were seeded in a 96-well plate, and to this CCK-8 (20 µl) was added. The enzyme microplate reader at 450 nm was used to record the absorbance. The inhibitory effect on cellular proliferation was obtained as per the given formula: Inhibitory activity (%) = (1 - Atest/Acontrol) × 100 %.
Cell cycle analysis
The effect of compound 8a (0, 10, 20, and 30 µM) was investigated on the cell cycle of Saos-2 cells as per our earlier reported procedure using a FACSCalibur flow cytometer with CellQuest V.3.3 software (BD Biosciences, USA) (38).
Flow cytometric apoptosis assay
The effect of compound 8a (0, 10, 20, and 30 µM) on apoptosis was investigated on Saos-2 cells as per our earlier reported procedure using a FACSCalibur flow cytometer with CellQuest V.3.3 software (BD Biosciences, USA) (38).
In vivo pharmacological activity
Surgical orthotopic implantation (SOI) for the establishment of the osteosarcoma PDOX model
The PDOX model in Athymic nu/nu nude mice was established according to our earlier reported procedure (38). The tumor tissue for implantation was obtained from a 10-year old OS patient with written informed consent.
Treatment protocol
The mice were arbitrarily categorized into four dissimilar groups (n=6), and the treatment schedule lasted for 14 days as follows. The compound 8a was dissolved in the solution of PEG400/Tween 80/Saline solution at 10/10/80 % in volume, respectively prior to intraperitoneal administration.
Group 1: Untreated
Groups 2, 3, and 4 received compound 8a (2, 5, and 10 mg/kg, respectively, IP, daily)
The control animals received the vehicle only.
The length and width of the tumor along with the bodyweight of mice were recorded.
The tumor volume was calculated with the following formula:
Tumor volume (mm3)= length (mm) × width (mm) × height (mm))⁄2
Examination of lung histopathology
At the end of the experiment, the lung tissues were harvested and fixed in formalin (10%). The tissues were further entrenched in paraffin, sectioned using a microtome into 5-μm thickness. The resulting sections were dyed using hematoxylin-eosin (HE).
Pharmacokinetic assessment
The compound 8a was administered to female SD rats in a single dose of 1 and 5 mg/kg using intra-venomous and per-oral route in the vehicle. The blood samples from the rats were collected in a timely manner starting from 2 min to 24 hr. The serum was extracted from the blood-aliquots for the estimation of various pharmacokinetic parameters (T1/2, Tmax, Cmax, AUC0-INF) developed using WinNonlin software using LC-MS/MS (Applied Biosystem, USA).
Statistical analysis
One-way analysis of variance (ANOVA) was conducted with the Tukey test for post-hoc analysis. The P-values of 0.05 or less were considered statistically significant.
Results
Chemistry
The earlier reported procedure by Guan and Jiang (40) was adopted to synthesize the target compounds and the authenticity of compounds was ascertained by using elemental analysis which was found in ± 0.4% of the theoretical values.
Kinase inhibition study
The inhibitory activity of designed analogs was tested against PI3K and mTOR and Imatinib as a positive control, Table 1. It has been found that all compounds 8a-f showed significant to moderate IC50 against both kinases in the nanomolar range. The compounds showed a diverse variety of inhibitory profiles against both kinases. Compound 8a exhibited outstanding inhibitory activity among the tested derivatives against PI3K (IC50 = 786 nM) and mTOR (IC50= 345 nM). In the next instance, on replacing chloro with bromo (8b), a slight reduction in kinase inhibitory activity was observed with further decrease in the case of compound 8c, containing p-methyl. The compound 8d having the p-nitro group demonstrated moderate improvement in inhibitory activity against the tested kinase. However, the removal of nitro and the insertion of hydroxy (OH) or methoxy (OCH3) do not significantly influence the inhibitory activity. These analogs showed mild to mostly minor activity against PI3K and mTOR. However, none of the synthesized compounds showed better activity than Imatinib (IC50 value of 312 nM and 214 nM against PI3K, and mTOR kinase, respectively).
Table 1.
Inhibitory activity of designed compounds against PI3K, mTOR, and anticancer activity against osteosarcoma cells
| Compound | R | Kinase inhibition IC50 (nM) | Cell growth inhibition IC50 (nM) |
|||
|---|---|---|---|---|---|---|
| K562 | KU812 | Saos-2 | ||||
| PI3K | mTOR | |||||
| 8a | 4-Cl | 786 | 345 | 620 | 722 | 210 |
| 8b | 4-Br | 885 | 389 | 730 | 830 | 268 |
| 8c | 4-CH3 | 967 | 490 | 900 | 1032 | 530 |
| 8d | 4-NO2 | 905 | 414 | 822 | 950 | 340 |
| 8e | 4-OH | 987 | 456 | 887 | 1140 | 478 |
| 8f | 4-OCH3 | 1247 | 834 | 1200 | 1234 | 905 |
| Imatinib | 312 | 214 | 410 | 165 | 332 | |
Anticancer activity
Impressed by the exceptional kinase inhibitory profile of the designed analogs, it is worthwhile to test its inhibitory activity against various osteosarcoma cells (K562, KU812, and Saos-2), Table 1. It has been shown that compound 8a inhibits the survival of both K562 and KU812. However, it showed potent inhibitory activity against Saos-2 (IC50= 210 nM) compared with Imatinib (IC50= 332 nM) as standard. The anti-proliferative activity of compounds 8b and 8c was found significantly reduced against all tested cell lines. The inhibitory potency was found significantly increased in the case of compound 8d, whereas compounds 8e and 8f showed reduction in inhibitory potency. On closely monitoring the above results, it was inferred that developed compounds showed an approximately similar inhibition pattern against the tested kinases and osteosarcoma cells. Compound 8a was the most potent analog among the tested series in both in vitro experiments, while compound 8f showed the least activity.
Impressed by the strong anticancer effect of compound 8a, we intend to perform the mechanistic analysis underlying its anticancer effect.
Effect on compound 8a cell cycle of Saos-2 cells
As shown in Figure 2, the compound 8a treated group showed that S-phase cells were found almost similar with increase in G2/M phase cells. These results indicated that compound 8a causes G2/M phase arrest.
Figure 2.
Effect of compound 8a on the cell cycle progression of Saos-2 cells, where: (A) control, (B) 10 µM, (C) 20 µM, (D) 30 µM, and (E) cell cycle division percentage
Effect of compound 8a on the apoptosis of Saos-2 cells
As shown in Figure 3, compound 8a dose-dependently increases apoptosis of Saos-2 cells in Annexin V/PI analysis as evidenced by an increase in the percent of apoptosis rate.
Figure 3.
Effect of compound 8a on cell apoptosis of Saos-2 cells determined by using flow cytometry, where: A) control, (B) 10 µM, (C) 20 µM, (D) 30 µM, and (E) comparative bar-graph of flow cytometry analysis estimating the percentage of cell apoptosis rate. Data were shown as mean ± SEM **P<0.01 vs control
In vivo activity
In continuation of the above experiments, in the next study, we have studied the bioactivity of compound 8a in the patient-derived orthotopic xenograft (PDOX) mouse model. Initially, the pharmacological benefit of molecule 8a was assessed based on two parameters, viz., body weight and relative tumor volume. As shown in Figure 4, mice treated with compound 8a showed improvement in body weight in comparison with control. The tumor volume was found significantly reduced in the 8a treated group at the end of the study. Thus, on the basis of the above results, it has been suggested that compound 8a showed excellent anti-cancer activity against patient-derived osteosarcoma cells.
Figure 4.
Anticancer effect of 8a on PDOX mouse model. (A) mice body weight, (B) relative tumor volume all through the study schedule, and (C) lung histopathology of mice corresponding to different treatment groups. Data are shown as mean ± SEM **P<0.01 vs control
Effect on lung metastasis
As shown in Figure 4C, the control group showed well-structured alveoli with no alterations. Compound 8a in low doses (2 mg/kg) does not have a significant effect on the metastasis of the lung as evident by disordered lung architecture, ruptured alveoli with some necrotic portion, and increased permeability due to interstitial hemorrhages. However, in medium dose at 5 mg/kg, mice revealed less necrotic lesions and minimum interstitial hemorrhages. In the high dose of compound 8a (10 mg/kg), the lung architecture of treated mice was found significantly restored close to normal with reduced disease lesions. Thus, it could be suggested that compound 8a significantly ameliorated lung metastasis of osteocarcinoma in a dose-dependent manner.
Pharmacokinetic assessment
As shown in Table 2, Compound 8a showed excellent pharmacokinetics with tmax and t1/2 of 160 min and 210 min, respectively in p.o. route. On the other hand, in i.v. route, compound 8a attained peak plasma level at 8 min with Cmax of 8126 suggesting that it distributed swiftly across the body-compartments. The AUC of compound 8a was found significantly acceptable in both tested dosing routes. Results of the above pharmacokinetic study confirm that compound 8a is well-tolerated with optimal pharmacokinetics.
Table 2.
Pharmacokinetic parameter of compound 8a in SD rats
| Parameter | PO (5 mg/kg) | IV (1 mg/kg) |
|---|---|---|
| T ½ (min) | 210 | 45 |
| T max (min) | 160 | 8 |
| C max (ng/ml) | 410 | 8126 |
| AUC 0- INF (hr*ng/mL) | 297326 | 61201 |
Scheme 1.
Reagents and conditions: a) Liq. NH3, 40-45 °C, NaHCO3, heat, 2–3 hr, b) NaOBu-t/THF 10 °C to RT, 2 hr, c) THF-TEA, 0 °C, 3 hr, d) reflux, 3–5 hr
Discussion
Osteosarcoma (OS) is a malignant tumor of bone that originates in the mesenchymal tissue and is responsible for 20% of all cases of primary malignant bone tumors in the world. In the early 70 sec, surgery was the only option to treat OS which later used chemotherapy as an adjuvant treatment to eliminate the formation of metastases that would not be possible to remove by surgery alone (2, 42). However, resistance to chemotherapy has compromised the clinical utility of current therapeutic modalities and decreased the overall prognosis of the disease (4). In our present study, we have successfully demonstrated the anti-osteosarcoma activity of 1,3,5-triazine derivatives as potent inhibitors of the PI3K/mTOR pathway.
Cell growth is mainly dependent upon the highly conserved biological process known as the cell cycle. Under abnormal circumstances, it has been found abruptly de-regulated and serves as a characteristic hallmark of cancer (43). Various cell-cycle-specific inhibitors were used as a primary therapeutic modality or in combination with other drugs against cancer (44, 45). Therefore, initially, we have enumerated the effect of the most potent inhibitor (8a) on the cell cycle of Saos-2 cells. Results of the study suggest that compound 8a causes G2/M phase arrest. Apoptosis is a process which is termed programmed cell death response to maintain tissue homeostasis. Studies have shown that apoptosis is found aberrantly unbridled in various cancers, including osteosarcoma (45). Results suggest that compound 8a causes a dose-dependent increase of apoptosis of Saos-2 cells. Thus, it is suggested that compound 8a showed a robust anticancer effect against osteosarcoma cells possibly by promoting apoptosis and cell cycle arrest of the G2/M phase. Concerning the above benefit of compound 8a against osteosarcoma, it is worthwhile to assess the pharmacological activity of 8a in in vivo experiments. Therefore, we have chosen our established patient-derived orthotopic xenograft (PDOX) mouse model for the bioactivity determination of compound 8a on various biochemical parameters. According to the American Cancer Society, body weight is considered the first noticeable symptom of the cancer effect. New molecule improves bodyweight because of the anticancer effect; whereas, relative tumor volume directly correlates with the anticancer effect of the test compound on the tumor tissues. The results suggest that compound 8a showed excellent anti-OS activity ascertained on the basis of decreased tumor volume and increase in body weight of 8a-treated mice at the end of the study.
The survivability of osteosarcoma patients has been seriously jeopardized due to lung metastases (46). As per the estimate, osteosarcoma has been found metastasized to the lungs of the patients at the time of the first diagnosis (47). Surgical resection is a current first-line of therapy to treat osteosarcoma patients affected with lung metastasis followed by a chemotherapy regimen (48). Despite this, the relapse of disease is quite frequent in the majority of cases even after using various chemotherapeutic drugs. Thus, the management of osteosarcoma patients with lung metastasis is quite challenging (39). Thus, it is imperative to define the effect of compound 8a on lung metastasis of the PDOX mice. It has been found that compound 8a significantly ameliorated lung metastasis of osteocarcinoma via restoring the lung architecture in a dose-dependent manner. The potency of any pharmacological agent is highly dependent on its bioavailability. It needs to stay in the body in a bioactive form long enough for the expected biological events to occur. Thus, the study of any new lead’s pharmacokinetic properties is imperative in the early drug discovery process. Concerning this and encouraged by the excellent pharmacological profile of compound 8a, lastly, we estimate its pharmacokinetics profile in SD rats. Results of the study suggested that compound 8a is well-tolerated with optimal pharmacokinetics.
Conclusion
In summary, a series of 1,3,5-triazine derivatives were designed and synthesized as new PI3K/mTOR inhibitors. The resulting compounds significantly attenuate the activity of both PI3K and mTOR and potently inhibit the propagation of various osteocarcinoma cells. The results of the above studies enumerated compound 8a as a potent inhibitor of Saos-2 cells. Compound 8a also induced apoptosis and causes G2/M phase arrest of Saos-2 cells. It also showed dose-dependent inhibition of tumor volume and increase in body weight in the patient-derived orthotopic xenograft (PDOX) mouse model. Compound 8a significantly ameliorated lung metastasis of osteocarcinoma via restoring the lung architecture in a dose-dependent manner and showed excellent bioavailability in the pharmacokinetic assay. Collectively, compound 8a is a capable anticancer lead for further development.
Authors’ Contributions
QS performed experiments and formal analysis, BX performed experiments, ZT performed experiments and analyzed the data, ZG conceptualized and supervised the study. All authors approved the current version of the manuscript.
Compliance with Ethical Standard
The ethical committee of Shanghai Jiao Tong University Affiliated Sixth People’s Hospital approved this study (IMREC/SPU/2020/A23). All animal experiments were conducted following the experimental animal guidelines set by the National Institutes of Health Guide for the Care and Use of Laboratory Animals.
Conflicts of Interest
The authors declare no conflicts of interest.
Acknowledgment
Authors are thankful to their respective institutions for infrastructural support of this study. The study did not receive any funding.
References
- 1.Bray F, Ferlay J, Soerjomataram I, Siegel RL, Torre LA, Jemal A. Global cancer statistics 2018: globocan estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 2018;68:394–424. doi: 10.3322/caac.21492. [DOI] [PubMed] [Google Scholar]
- 2.Czarnecka AM, Synoradzki K, Firlej W, Bartnik E, Sobczuk P, Fiedorowicz M, et al. Molecular biology of osteosarcoma. Cancers. 2020;12:1–27. doi: 10.3390/cancers12082130. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Durfee RA, Mohammed M, Luu HH. Review of osteosarcoma and current management. Rheumatol Ther. 2016;3:221–243. doi: 10.1007/s40744-016-0046-y. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Bielack SS, Hecker-Nolting S, Blattmann C, Kager L. Advances in the management of osteosarcoma. F1000Res. 2016;5:2767–2777. doi: 10.12688/f1000research.9465.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Savage DG, Antman KH. Imatinib mesylate — a new oral targeted therapy. N Engl J Med. 2002;346:683–693. doi: 10.1056/NEJMra013339. [DOI] [PubMed] [Google Scholar]
- 6.O’Brien SG, Guilhot F, Larson RA, Gathmann I, Baccarani M, Cervantes F, et al. Imatinib compared with interferon and low-dose cytarabine for newly diagnosed chronic-phase chronic myeloid leukemia. N Engl J Med. 2003;348:994–1004. doi: 10.1056/NEJMoa022457. [DOI] [PubMed] [Google Scholar]
- 7.Verweij J, Van Oosterom A, Blay JY, Judson I, Rodenhuis S, Van Der Graaf W, et al. Imatinib mesylate (STI-571 Glivec®, GleevecTM) is an active agent for gastrointestinal stromal tumours, but does not yield responses in other soft-tissue sarcomas that are unselected for a molecular target: results from an EORTC soft tissue and bone sarcom. Eur J Cancer. 2003;39:2006–2011. [PubMed] [Google Scholar]
- 8.El Hajj Dib I, Gallet M, Mentaverri R, Sévenet N, Brazier M, Kamel S. Imatinib mesylate (Gleevec®) enhances mature osteoclast apoptosis and suppresses osteoclast bone resorbing activity. Eur J Pharmacol. 2006;551:27–33. doi: 10.1016/j.ejphar.2006.09.007. [DOI] [PubMed] [Google Scholar]
- 9.O’Sullivan S, Naot D, Callon K, Porteous F, Horne A, Wattie D, et al. Imatinib promotes osteoblast differentiation by inhibiting PDGFR signaling and inhibits osteoclastogenesis by both direct and stromal cell-dependent mechanisms. J Bone Miner Res. 2007;22:1679–1689. doi: 10.1359/jbmr.070719. [DOI] [PubMed] [Google Scholar]
- 10.Fierro F, Illmer T, Jing D, Schleyer E, Ehninger G, Boxberger S, et al. Inhibition of platelet-derived growth factor receptorβ by imatinib mesylate suppresses proliferation and alters differentiation of human mesenchymal stem cells in vitro. Cell Prolif. 2007;40:355–366. doi: 10.1111/j.1365-2184.2007.00438.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Gobin B, Moriceau G, Ory B, Charrier C, Brion R, Blanchard F, et al. Imatinib mesylate exerts anti-proliferative effects on osteosarcoma cells and inhibits the tumour growth in immunocompetent murine models. PLoS One. 2014;9:1–12. doi: 10.1371/journal.pone.0090795. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Bishop MW, Janeway KA. Emerging concepts for PI3K/mTOR inhibition as a potential treatment for osteosarcoma. F1000Res. 2016;5:1–6. doi: 10.12688/f1000research.8228.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Penel-Page M, Ray-Coquard I, Larcade J, Girodet M, Bouclier L, Rogasik M, et al. Off-label use of targeted therapies in osteosarcomas: data from the french registry OUTC’S (observatoire de i’utilisation des thérapies ciblées dans les sarcomes) BMC Cancer. 2015;15:854–862. doi: 10.1186/s12885-015-1894-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Zhang J, Yang PL, Gray NS. Targeting cancer with small molecule kinase inhibitors. Nat Rev Cancer. 2009;9:28–39. doi: 10.1038/nrc2559. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Srivastava JK, Dubey P, Singh S, Bhat HR, Kumawat MK, Singh UP. Discovery of novel 1,3,5-triazine-thiazolidine-2,4-diones as dipeptidyl peptidase-4 inhibitors with antibacterial activity targeting the S1 pocket for the treatment of type 2 diabetes. RSC Adv. 2015;5:14095–14102. [Google Scholar]
- 16.Solankee A, Kapadia K, Ana Ćirić, Soković M, Doytchinova I, Geronikaki A. Synthesis of some new S-triazine based chalcones and their derivatives as potent antimicrobial agents. Eur J Med Chem. 2010;45:510–518. doi: 10.1016/j.ejmech.2009.10.037. [DOI] [PubMed] [Google Scholar]
- 17.Singh UP, Singh RK, Bhat HR, Subhashchandra YP, Kumar V, Kumawat MK, et al. Synthesis and antibacterial evaluation of series of novel tri-substituted-s-triazine derivatives. Med Chem Res. 2011;20:1603–1610. [Google Scholar]
- 18.Kumar Ghosh S, Saha A, Hazarika B, Pratap Singh U, Raj Bhat H, Gahtori P. Design, facile synthesis, antibacterial activity and structure-activity relationship of novel di- and tri-substituted 1,3,5-triazines. Lett Drug Des Discov. 2012;9:329–335. [Google Scholar]
- 19.Bhat HR, Pandey PK, Ghosh SK, Singh UP. Development of 4-aminoquinoline-1,3,5-triazine conjugates as potent antibacterial agent through facile synthetic route. Med Chem Res. 2013;22:5056–5065. [Google Scholar]
- 20.Singh B, Bhat HR, Kumawat MK, Singh UP. Structure-guided discovery of 1,3,5-triazine-pyrazole conjugates as antibacterial and antibiofilm agent against pathogens causing human diseases with favorable metabolic fate. Bioorganic Med Chem Lett. 2014;24:3321–3325. doi: 10.1016/j.bmcl.2014.05.103. [DOI] [PubMed] [Google Scholar]
- 21.Singh UP, Bhat HR, Gahtori P. Antifungal activity, SAR and physicochemical correlation of some thiazole-1,3,5-triazine derivatives. J Mycol Med. 2012;22:134–141. doi: 10.1016/j.mycmed.2011.12.073. [DOI] [PubMed] [Google Scholar]
- 22.Singh UP, Bhat HR, Gahtori P, Singh RK. Hybrid phenylthiazole and 1,3,5-triazine target cytosolic leucyl-tRNA synthetase for antifungal action as revealed by molecular docking studies. Silico Pharmacol. 2013;1:3–11. doi: 10.1186/2193-9616-1-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Milata V, Reinprecht L, Kizlink J. Synthesis and antifungal efficacy of 1,3,5-triazines. Acta Chim Slovaca. 2012;5:95–99. [Google Scholar]
- 24.Bhat HR, Singh UP, Yadav PS, Kumar V, Gahtori P, Das A, et al. Synthesis, characterization and antimalarial activity of hybrid 4-aminoquinoline-1,3,5-triazine derivatives. Arab J Chem. 2016;9:625–631. [Google Scholar]
- 25.Bhat HR, Singh UP, Thakur A, Kumar Ghosh S, Gogoi K, Prakash A, et al. Synthesis, antimalarial activity and molecular docking of hybrid 4-aminoquinoline-1,3,5-triazine derivatives. Exp Parasitol. 2015;157:59–67. doi: 10.1016/j.exppara.2015.06.016. [DOI] [PubMed] [Google Scholar]
- 26.Bhat HR, Singh UP, Gahtori P, Ghosh SK, Gogoi K, Prakash A, et al. Antimalarial activity and docking studies of novel bi-functional hybrids derived from 4-aminoquinoline and 1,3,5-triazine against wild and mutant malaria parasites as pf-DHFR inhibitor. RSC Adv. 2013;3:2942–2952. [Google Scholar]
- 27.Sunduru N, Sharma M, Srivastava K, Rajakumar S, Puri SK, Saxena JK, et al. Synthesis of oxalamide and triazine derivatives as a novel class of hybrid 4-aminoquinoline with potent antiplasmodial activity. Bioorganic Med Chem. 2009;17:6451–6462. doi: 10.1016/j.bmc.2009.05.075. [DOI] [PubMed] [Google Scholar]
- 28.Gahtori P, Ghosh SK, Parida P, Prakash A, Gogoi K, Bhat HR, et al. Antimalarial evaluation and docking studies of hybrid phenylthiazolyl-1,3,5-triazine derivatives: a novel and potential antifolate lead for Pf-DHFR-TS inhibition. Exp Parasitol. 2012;130:292–299. doi: 10.1016/j.exppara.2011.12.014. [DOI] [PubMed] [Google Scholar]
- 29.Bhat HR, Singh UP, Gahtori P, Ghosh SK, Gogoi K, Prakash A, et al. Synthesis, docking, in vitro and in vivo antimalarial activity of hybrid 4-aminoquinoline-1,3,5-triazine derivatives against wild and mutant malaria parasites. Chem Biol Drug Des. 2015;86:265–271. doi: 10.1111/cbdd.12490. [DOI] [PubMed] [Google Scholar]
- 30.Lozano V, Aguado L, Hoorelbeke B, Renders M, Camarasa MJ, Schols D, et al. Targeting HIV entry through interaction with envelope glycoprotein 120 (gp120): synthesis and antiviral evaluation of 1,3,5-triazines with aromatic amino acids. J Med Chem. 2011;54:5335–5348. doi: 10.1021/jm200560r. [DOI] [PubMed] [Google Scholar]
- 31.Srivastava JK, Awatade NT, Bhat HR, Kmit A, Mendes K, Ramos M, et al. Pharmacological evaluation of hybrid thiazolidin-4-one-1,3,5-triazines for NF-κB, biofilm and CFTR activity. RSC Adv. 2015;5:88710–88718. [Google Scholar]
- 32.Cascioferro S, Parrino B, Spanò V, Carbone A, Montalbano A, Barraja P, et al. 1,3,5-Triazines: a promising scaffold for anticancer drugs development. Eur J Med Chem. 2017;142:523–549. doi: 10.1016/j.ejmech.2017.09.035. [DOI] [PubMed] [Google Scholar]
- 33.Popowycz F, Fournet G, Schneider C, Bettayeb K, Ferandin Y, Lamigeon C, et al. Pyrazolo[1,5-a]-1,3,5-triazine as a purine bioisostere: access to potent cyclin-dependent kinase inhibitor (R)-roscovitine analogue. J Med Chem. 2009;52:655–663. doi: 10.1021/jm801340z. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 34.Srivastava JK, Pillai GG, Bhat HR, Verma A, Singh UP. Design and discovery of novel monastrol-1,3,5-triazines as potent anti-breast cancer agent via attenuating epidermal growth factor receptor tyrosine kinase. Sci Rep. 2017;7:5851–5868. doi: 10.1038/s41598-017-05934-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 35.Yaguchi SI, Fukui Y, Koshimizu I, Yoshimi H, Matsuno T, Gouda H, et al. Antitumor activity of ZSTK474, a new phosphatidylinositol 3-kinase inhibitor. J Natl Cancer Inst. 2006;98:545–556. doi: 10.1093/jnci/djj133. [DOI] [PubMed] [Google Scholar]
- 36.Sciú ML, Sebastián-Pérez V, Martinez-Gonzalez L, Benitez R, Perez DI, Pérez C, et al. Computer-aided molecular design of pyrazolotriazines targeting glycogen synthase kinase 3. J Enzyme Inhib Med Chem. 2019;34:87–96. doi: 10.1080/14756366.2018.1530223. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 37.Singla P, Luxami V, Paul K. Synthesis and in vitro evaluation of novel triazine analogues as anticancer agents and their interaction studies with bovine serum albumin. Eur J Med Chem. 2016;117:59–69. doi: 10.1016/j.ejmech.2016.03.088. [DOI] [PubMed] [Google Scholar]
- 38.Su Q, Xu B, Tian Z, Gong Z. Novel 1,3,5‐triazine‐nicotinohydrazide derivatives induce cell arrest and apoptosis in osteosarcoma cancer cells and inhibit osteosarcoma in a patient‐derived orthotopic xenograft mouse model. Chem Biol Drug Des. 2022;99:320–330. doi: 10.1111/cbdd.13986. [DOI] [PubMed] [Google Scholar]
- 39.Huang X, Zhao J, Bai J, Shen H, Zhang B, Deng L, et al. Risk and clinicopathological features of osteosarcoma metastasis to the lung: a population-based study. J Bone Oncol. 2019;16:100230–100237. doi: 10.1016/j.jbo.2019.100230. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 40.Guan B, Jiang C. Design and development of 1,3,5-triazine derivatives as protective agent against spinal cord injury in rat via inhibition of NF-ĸB. Bioorganic Med Chem Lett. 2021;41:127964–127971. doi: 10.1016/j.bmcl.2021.127964. [DOI] [PubMed] [Google Scholar]
- 41.Higuchi T, Miyake K, Oshiro H, Sugisawa N, Yamamoto N, Hayashi K, et al. Trabectedin and irinotecan combination regresses a cisplatinum-resistant osteosarcoma in a patient-derived orthotopic xenograft nude-mouse model. Biochem Biophys Res Commun. 2019;513:326–331. doi: 10.1016/j.bbrc.2019.03.191. [DOI] [PubMed] [Google Scholar]
- 42.Li J, Yang Z, Li Y, Xia J, Li D, Li H, et al. Cell apoptosis, autophagy and necroptosis in osteosarcoma treatment. Oncotarget. 2016;7:44763–44778. doi: 10.18632/oncotarget.8206. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 43.Jingwen B, Yaochen L, Guojun Z. Cell cycle regulation and anticancer drug discovery. Cancer Biol Med. 2017;14:348–362. doi: 10.20892/j.issn.2095-3941.2017.0033. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 44.Raghavendra NM, Pingili D, Kadasi S, Mettu A, Prasad SVUM. Dual or multi-targeting inhibitors: the next generation anticancer agents. Eur J Med Chem. 2018;143:1277–1300. doi: 10.1016/j.ejmech.2017.10.021. [DOI] [PubMed] [Google Scholar]
- 45.Geromichalos GD, Alifieris CE, Geromichalou EG, Trafalis DT. Overview on the current status on virtual high-throughput screening and combinatorial chemistry approaches in multi-target anticancer drug discovery; part II. J BUON. 2016;21:1337–1358. [PubMed] [Google Scholar]
- 46.Isakoff MS, Bielack SS, Meltzer P, Gorlick R. Osteosarcoma: current treatment and a collaborative pathway to success. J Clin Oncol. 2015;33:3029–3035. doi: 10.1200/JCO.2014.59.4895. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 47.Kaste SC, Pratt CB, Cain AM, Jones-Wallace DJ, Rao BN. Metastases detected at the time of diagnosis of primary pediatric extremity osteosarcoma at diagnosis: imaging features. Cancer. 1999;86:1602–1608. doi: 10.1002/(sici)1097-0142(19991015)86:8<1602::aid-cncr31>3.0.co;2-r. [DOI] [PubMed] [Google Scholar]
- 48.Nataraj V, Rastogi S, Khan SA, Sharma MC, Agarwala S, Vishnubhatla S, et al. Prognosticating metastatic osteosarcoma treated with uniform chemotherapy protocol without high dose methotrexate and delayed metastasectomy: a single center experience of 102 patients. Clin Transl Oncol. 2016;18:937–944. doi: 10.1007/s12094-015-1467-8. [DOI] [PubMed] [Google Scholar]




