Research progress on small molecule inhibitors targeting KRAS G12C with acrylamide structure and the strategies for solving KRAS inhibitor resistance.

KRAS (Kirsten-RAS) is a highly mutated gene in the RAS (rat sarcoma) gene family that acts as a critical switch in intracellular signaling pathways, regulating cell proliferation, differentiation, and survival. The continuous activation of KRAS protein resulting from mutations leads to the activation of multiple downstream signaling pathways, inducing the development of malignant tumors. Despite the significant role of KRAS in tumorigenesis, targeted drugs against KRAS gene mutations have failed, and KRAS was once considered an undruggable target. The development of KRAS G12C mutant conformational modulators and the introduction of Sotorasib (R&D code: AMG510) have been a breakthrough in this field, with its remarkable clinical outcomes. Consequently, there is now a great number of KRAS G12C mutations. Patent applications for mutant GTPase KRAS G12C inhibitors, which are said to be covalently modified by cysteine codon 12, have been submitted since 2014. This review classifies KRAS G12C inhibitors based on their chemical structure and evaluates their biological properties. Additionally, it discusses the obstacles encountered in KRAS inhibitor research and the corresponding solutions.

Novel quinazoline-based dual EGFR/c-Met inhibitors overcoming drug resistance for the treatment of NSCLC: Design, synthesis and anti-tumor activity.

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) have demonstrated the ability to impede tumor cell proliferation by suppressing EGFR expression. Nonetheless, patients undergoing treatment may acquire resistance, which may occur through an EGFR-dependent (such as T790M mutation) or an EGFR-independent (such as c-Met amplification) manner. Therefore, developing dual-target inhibitors might present a potential avenue for addressing treatment-acquired resistance in patients. Herein, we designed, synthesized, and screened several novel 4-phenoxyquinazoline derivatives, aiming to identify a potent dual EGFR/c-Met inhibitor for the treatment of NSCLC, among which H-22 emerged as the most promising candidate exhibiting significant antitumor properties. Moreover, we assessed the in vitro inhibitory effect of H-22 on EGFR kinase and c-Met kinase in five cancer cell lines. In addition, a series of functional experiments (cell cycle, apoptosis assays, in vitro/in vivo animal model, etc.) were conducted to further investigate the anti-tumor mechanisms of H-22. The present study revealed that H-22 exhibited strong antitumor activity both in vitro and in vivo. Interestingly, H-22 exhibited anti-proliferative activity (2.27-3.35 µM) similar to Afatinib against all five cancer cells, with inhibitory functions against EGFRWT, EGFRL858R/T790M, and c-Met kinases at a concentration of 64.8, 305.4 and 137.4 nM, respectively. Cell cycle analysis indicated that the antiproliferative activity of H-22 was associated with its ability to cause G2/M arrest. Furthermore, in vivo data showed that H-22 could inhibit tumor growth in our xenograft models and induce apoptosis. Collectively, our findings uncovered that H-22 is a novel dual EGFR and c-Met inhibitor and a prospective anti-tumor therapeutic drug.

Design, synthesis, and evaluation of antitumor activity of Mobocertinib derivatives, a third-generation EGFR inhibitor.

Mobocertinib, as a structural analog of the third generation TKI Osimertinib, can selectively act on the EGFRex20 mutation. We have structurally modified Mobocertinib to obtain new EGFR inhibitors. In this paper, we chose Mobocertinib as a lead compound for structural modification to investigate the effect of Mobocertinib derivatives on EGFRT790M mutation. We designed and synthesized 63 Mobocertinib derivatives by structural modification using the structural similarity strategy and the bioelectronic isoarrangement principle. Then, we evaluated the in vitro antitumor activity of the 63 Mobocertinib derivatives and found that the IC50 of compound H-13 against EGFRL858R/T790M mutated H1975 cells was 3.91 µM, and in further kinase activity evaluation, the IC50 of H-13 against EGFRL858R/T790M kinase was 395.2 nM. In addition, the preferred compound H-13 was able to promote apoptosis of H1975 tumor cells and block the proliferation of H1975 cells in the G0/G1 phase; meanwhile, it was able to significantly inhibit the migratory ability of H1975 tumor cells and inhibit the growth of H1975 cells in a time-concentration-dependent manner. In the in vivo anti-tumor activity study, the preferred compound H-13 had no obvious toxicity to normal mice, and the tumor inhibition effect on H1975 cell-loaded nude mice was close to that of Mobocertinib. Finally, molecular dynamics simulations showed that the binding energy between compound H-13 and 3IKA protein was calculated to be -162.417 ± 14.559 kJ/mol. In summary, the preferred compound H-13 can be a potential third-generation EGFR inhibitor.

Discovery of novel 4-arylamino-quinazoline derivatives as EGFRL858R/T790M inhibitors with the potential to inhibit the non-small cell lung cancers.

Three series of quinazoline derivatives (7a-j, 8a-o, 9a-l) were designed and synthesized as EGFRL858R/T790M inhibitors. Series 7a-j and 8a-o are urea and thiourea derivatives while category 9a-l contain the Michael receptor active warhead. Most of the compounds exhibited excellent anti-proliferative activity in vitro against several cancer cell lines, including non-small cell lung cancer (NSCLC) cell lines A549 and H1975, among which 14 compounds had strong antiproliferative activity against A549 and H1975 cancer cells. What's more, they also showed moderate to excellent kinase inhibitory activity against EGFRWT and EGFRL858R/T790M. 8o exhibited the best kinase inhibitory activity with IC50 values of 0.8, 2.7 nM against EGFRWT and EGFRL858R/T790M, respectively. Moreover, AO single staining and Annexin V-FITC/PI staining results also indicated that both 8o and 9b significantly induced apoptosis in A549 cells. 8o arrested the cell cycle at S phase and 9b arrested the cell cycle at G1 phase.

Design, synthesis and pharmacological evaluation of 2-arylurea-1,3,5-triazine derivative (XIN-9): A novel potent dual PI3K/mTOR inhibitor for cancer therapy.

Blocking the PI3K/AKT/mTOR pathway has been widely recognized as an attractive cancer therapeutic strategy because of its crucial role in cell growth and survival. In this study, a novel series of 2-arylurea-1,3,5-triazine derivatives had been synthesized and evaluated as highly potent PI3K and mTOR inhibitors. The new compounds exhibited cytotoxic activities against MCF-7, Hela and A549 cancer cell lines (IC50 = 0.03-36.54 µM). The most promising compound XIN-9 exhibited potent inhibition against PI3K and mTOR kinase (IC50 = 23.8 and 10.9 nM). Mechanistic study using real-time PCR revealed the ability of XIN-9 to inhibit PI3K and mTOR. In addition, compound XIN-9 arrested the cell cycle of MCF-7 cells at the G0/G1 phase. XIN-9 also caused a significant dose-dependent increase of early and late apoptotic events. Molecular docking analysis revealed a high binding affinity for XIN-9 toward PI3K and mTOR. Following in vitro studies, XIN-9 was further evaluated in MCF-7 xenograft models to show significant in vivo anticancer efficacies with tumor growth inhibitions of 41.67% (po, 75 mg/kg). Overall, this work indicated that compound XIN-9 represents a potential anticancer targeting PI3K/AKT/mTOR pathway.

Design, synthesis and biological evaluation of novel 4-(pyrrolo[2,3-d]pyrimidine-4-yloxy)benzamide derivatives as potential antitumor agents.

Cancer is a major cause of death worldwide. Small molecule inhibitors have become a major therapeutic treatment for cancer. In this study, a series of novel 4-(pyrrolo[2,3-d]pyrimidine-4-yloxy)benzamide derivatives were designed, synthesized and evaluated for their antitumor activity against the A549, Hela and MCF-7 cell lines. Among them, the optimal compound 35 was found to possess excellent inhibitory activity against the A549, Hela and MCF-7 cell lines with IC50 values of 5.29 ± 0.58, 3.72 ± 0.91, and 9.23 ± 0.56 µM, which were superior to Golvatinib. The structure-activity relationship showed that the introduction of 7H-pyrrolo[2,3-d]pyrimidine along with the F atom of the central and terminal benzene was beneficial to the improvement of inhibitory activity of the target compounds. Besides, we took further study on the combined mode between compound 35 and c-Met kinase through molecular docking.

Design, synthesis and evaluation of anti-proliferative activity of 2-aryl-4-aminoquinazoline derivatives as EGFR inhibitors.

A class of 2-aryl-4-aminoquinazoline derivatives (7a-7j, 8a-8h, 9a-9h and 10a-10k) were designed, synthesized and evaluated as EGFR inhibitors. The anti-proliferative activity of compounds in vitro showed that compound 9e was considered to be a promising derivative. Compared with the lead compound Angew2017-7634-1, 9e exhibited excellent inhibitory activity against A549, NCI-H460 and H1975 cell lines, with IC50 values of 14.33 ± 1.16 µM, 17.81 ± 1.25 µM and 13.41 ± 1.14 µM, respectively. Moreover, 9e could effectively inhibit against Ba/F3-EGFRDel19/T790M/C797S cell lines. In the kinase experiment, the most promising compound 9e exhibited excellent enzymatic inhibitory activity and selectivity for EGFRL858R/T790M, with an IC50 value of 0.74 µM. Further activity studies showed that 9e could not only induce remarkable cell-apoptosis of A549, but also block A549 cell lines in S-phase in a concentration-dependent manner. Furthermore, molecular docking study revealed the binding mode of 9e. All in all, we analyzed the structure-activity relationship of the target compounds, and explored their mechanism of action.

Design, Synthesis, and Antitumor Activity of Olmutinib Derivatives Containing Acrylamide Moiety.

Two series of olmutinib derivatives containing an acrylamide moiety were designed and synthesized, and their IC50 values against cancer cell lines (A549, H1975, NCI-H460, LO2, and MCF-7) were evaluated. Most of the compounds exhibited moderate cytotoxic activity against the five cancer cell lines. The most promising compound, H10, showed not only excellent activity against EGFR kinase but also positive biological activity against PI3K kinase. The structure-activity relationship (SAR) suggested that the introduction of dimethylamine scaffolds with smaller spatial structures was more favorable for antitumor activity. Additionally, the substitution of different acrylamide side chains had different effects on the activity of compounds. Generally, compounds H7 and H10 were confirmed as promising antitumor agents.

Design, synthesis and biological evaluation of 4-(pyridin-4-yloxy)benzamide derivatives bearing a 5-methylpyridazin-3(2H)-one fragment.

A series of 4-(pyridin-4-yloxy)benzamide derivatives bearing a 5-methylpyridazin-3(2H)-one fragment were designed, synthesized, and evaluated for their biological activity. Most compounds showed effective inhibitory activity against cancer cell lines of A549, HeLa and MCF-7. Among them, the most promising compound 40 showed excellent activity against A549, HeLa and MCF-7 cell lines with IC50 values of 1.03, 1.15 and 2.59 µM, respectively, which was 2.606.95 times more active than that of Golvatinib. The structure-activity relationships (SARs) showed that the introduction of 5-methylpyridazin-3(2H)-one to "5-atom linker" and the modification of the amide with morpholine group were beneficial for enhancing the inhibitory activity of compounds. In addition, the further research on compound 40 mainly include c-Met kinase activity, concentration dependence, apoptosis (acridine orange staining), and molecular docking.

Discovery of novel pyrrolo[2,3-b]pyridine derivatives bearing 4-oxoquinoline moiety as potential antitumor inhibitor.

A series of pyrrolo[2,3-b]pyridine derivatives bearing 4-oxoquinoline moiety were designed, synthesized and evaluated for the anti-proliferative on three cancer cell lines (A549, HepG2 and MCF-7) in vitro. Most of the compounds showed moderate to high potency. Some excellent compounds were tested for the inhibitory activity of c-Met kinase. Compound 34 (c-Met IC50 = 17 nM) was investigated the selectivity against Flt-3, c-Kit, VEGFR-2, ALK, PDGFR-ß and RON. Structure-activity relationship studies indicated that hydrogen, fluorine atom, and mono-electron-withdrawing groups (mono-EWGs, such as R2 = F) on R, R1 and R2, respectively, were beneficial for the anti-proliferative activities of the target compounds. Besides, we have took further study on the combined mode between compound 34 and c-Met kinase through molecular docking.

Discovery of thiapyran-pyrimidine derivatives as potential EGFR inhibitors.

A series of novel thiapyran-pyrimidine derivatives (10a-10h, 11a-11g, 12a-12f, 13a-13f, 14a-14f) were synthesized and their antiproliferative activities were tested. Most of the target compounds showed good activity on one or more cancer cell lines but low activity on human normal cell LO2. The most promising compound 13a exhibited the similar IC50 values on A549 and H1975 cell lines to the lead drug Olmutinib, and exhibited excellent activity and selectivity on EGFRT790M/L858R in the kinase experiment. AO and Hoechst33258 staining indicated that 13a could effectively induce H1975 cells apoptosis. Cell cycle and apoptosis analysis suggested that 13a could block cancer cells in G2/M phase and induce into late apoptosis in a manner of concentration-dependent. The structure-activity relationship of 13a was analyzed to explore its mechanism. All the results showed that 13a was a promising EGFR inhibitor.

Design, synthesis and biological evaluation of substituted 2-(thiophen-2-yl)-1,3,5-triazine derivatives as potential dual PI3Kα/mTOR inhibitors.

The phosphoinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) have been regarded as promising targets for the treatment of cancer. Herein, we synthesized a new series of substituted 2-(thiophen-2-yl)-1,3,5-triazine derivatives as novel PI3Kα/mTOR dual inhibitors for cancer therapy. All compounds were evaluated for the IC50 values against three cancer cell lines (A549, MCF-7 and Hela). Most of the target compounds exhibited moderate to excellent anti-tumor activities against these three tested cancer cell lines especially against A549 and Hela cancer cell lines. Among them, the most promising compound 13g showed excellent anti-tumor potency for A549, MCF-7 and Hela cell lines with IC50 values of 0.20 ± 0.05 µM, 1.25 ± 0.11 µM and 1.03 ± 0.24 µM, respectively. Notably, according to the result of enzymatic activity assay, compound 13g was identified as a novel PI3Kα/mTOR dual inhibitor, which had an approximately 10-fold improvement in mTOR inhibition, compared to the class I PI3K inhibitor 1 (pictilisib, GDC-0941), with IC50 values of 525 nM to 48 nM. And western blot analysis indicated compound 13g could efficiently suppress the phosphorylation of AKT at the dose of 0.1 µM, which further demonstrated compound 13g had significant inhibitory effect on the PI3K/Akt/mTOR pathway. Furthermore, compound 13g could stimulate A549 cells arrest at G0/G1 phase in a dose-dependent manner, and induced apoptosis at a low concentration.

Research Progress of Small Molecule VEGFR/c-Met Inhibitors as Anticancer Agents (2016-Present).

Vascular endothelial growth factor receptor 2 (VEGFR-2) binds to VEGFR-A, VEGFR-C and VEGFR-D and participates in the formation of tumor blood vessels, mediates the proliferation of endothelial cells, enhances microvascular permeability, and blocks apoptosis. Blocking or downregulating the signal transduction of VEGFR is the main way to discover new drugs for many human angiogenesis-dependent malignancies. Mesenchymal epithelial transfer factor tyrosine kinase (c-Met) is a high affinity receptor for hepatocyte growth factor (HGF). Abnormal c-Met signaling plays an important role in the formation, invasion and metastasis of human tumors. Therefore, the HGF/c-Met signaling pathway has become a significant target for cancer treatment. Related studies have shown that the conduction of the VEGFR and c-Met signaling pathways has a synergistic effect in inducing angiogenesis and inhibiting tumor growth. In recent years, multi-target small molecule inhibitors have become a research hotspot, among which the research of VEGFR and c-Met dual-target small molecule inhibitors has become more and more extensive. In this review, we comprehensively summarize the chemical structures and biological characteristics of novel VEGFR/c-Met dual-target small-molecule inhibitors in the past five years.

Design, synthesis and biological evaluation of novel 4-anlinoquinazoline derivatives as EGFR inhibitors with the potential to inhibit the gefitinib-resistant nonsmall cell lung cancers.

A series of quinazoline derivatives with benzylidene hydrazine carboxamide were designed and synthesised as EGFR inhibitors. Most compounds exhibited exceptional anti-proliferative activity against A549, HepG2, MCF-7 and H1975 cells. Furthermore, six compounds demonstrated excellent inhibition activity against EGFRWT with the IC50 value both less than 2 nM. Among the six compounds, 44 exhibited the strongest activity (0.4 nM) and potently inhibited EGFRL858R/T790M (0.1 µM). Excitingly, the most potent compound 14 showed excellent enzyme inhibitory activity with 6.3 nM and 8.4 nM for both EGFRWT and EGFRT790M/L858R. The result of AO single staining and Annexin V/PI staining showed that the compound 14 and 44 could induce remarkable apoptosis of A549 cells. The compound 14 arrested the cell cycle at the S phase and compound 44 arrested the cell cycle at the G0 phase in A549 cells. These preliminary results demonstrate that compound 14 and 44 may be promising lead compound-targeting EGFR.

Design, Synthesis, and Biological Evaluation of Pyridineamide Derivatives Containing a 1,2,3-Triazole Fragment as Type II c-Met Inhibitors.

A series of 4-(pyridin-4-yloxy)benzamide derivatives containing a 1,2,3-triazole fragment were designed, synthesized, and their inhibitory activity against A549, HeLa, and MCF-7 cancer cell lines was evaluated. Most compounds exhibited moderate to potent antitumor activity against the three cell lines. Among them, the promising compound B26 showed stronger inhibitory activity than Golvatinib, with IC50 values of 3.22, 4.33, and 5.82 µM against A549, HeLa, and MCF-7 cell lines, respectively. The structure-activity relationships (SARs) demonstrated that the modification of the terminal benzene ring with a single electron-withdrawing substituent (fluorine atom) and the introduction of a pyridine amide chain with a strong hydrophilic group (morpholine) to the hinge region greatly improved the antitumor activity. Meanwhile, the optimal compound B26 showed potent biological activity in some pharmacological experiments in vitro, such as cell morphology study, dose-dependent test, kinase activity assay, and cell cycle experiment. Finally, the molecular docking simulation was performed to further explore the binding mode of compound B26 with c-Met.

Design, Synthesis, and Biological Evaluation of Novel Thienopyrimidine Derivatives as PI3Kα Inhibitors.

Three series of novel thienopyrimidine derivatives 9a-l, 15a-l, and 18a-h were designed and synthesized, and their IC50 values against four cancer cell lines HepG-2, A549, PC-3, and MCF-7 were evaluated. Most compounds show moderate cytotoxicity against the tested cancer cell lines. The most promising compound 9a showed moderate activity with IC50 values of 12.32 ± 0.96, 11.30 ± 1.19, 14.69 ± 1.32, and 9.80 ± 0.93 µM, respectively. The inhibitory activities of compounds 9a and 15a against PI3Kα and mTOR kinase were further evaluated. Compound 9a exhibited PI3Kα kinase inhibitory activity with IC50 of 9.47 ± 0.63 µM. In addition, docking studies of compounds 9a and 15a were also investigated.

Discovery of novel 2-substituted-4-phenoxypyridine derivatives as potential antitumor agents.

A series of 2-substituted-4-phenoxypyridine derivatives were designed, synthesized, and evaluated for their antiproliferative activity against 4 cancer cell lines (A549, HT-29, H460, and U87MG) in vitro. Most compounds showed moderate to excellent potency. Nine tyrosine kinases (c-Met, Flt-3, ALK, VEGFR-2, VEGFR-3, PDGFR-α, PDGFR-ß, c-Kit, and EGFR) were used to evaluate the inhibitory activities with the most promising analogue 39, which showed the Flt-3/c-Met IC50 values of 2.18/2.61 nM. Structure-activity relationship studies indicated that n-Pr served as R1 group showed a higher preference, and stronger mono-EWGs on the phenyl ring (such as R2 = 4-F) was benefited to the potency.

Synthesis and bioevaluation study of novel N-methylpicolinamide and thienopyrimidine derivatives as selectivity c-Met kinase inhibitors.

Four series of N-methylpicolinamide moiety and thienopyrimidine moiety bearing pyridazinone were designed and synthesized and evaluated for the IC50 values against three cancer cell lines (A549, HepG2 and MCF-7) and some selected compounds were further evaluated for the activity against c-Met, Flt-3, VEGFR-2, c-Kit and EGFR kinases. Three compounds (35, 39 and 43) showed more active than positive control Foretinib against A549, HepG2 and MCF-7 cell lines. The most promising compound 43 showed superior activity against A549, HepG2 and MCF-7, with the IC50 values of 0.58 ±â€¯0.15 µM, 0.47 ±â€¯0.06 µM and 0.74 ±â€¯0.12 µM, which were 3.73-5.39-fold more activity than Foretinib, respectively. The experiments of enzyme-based showed that 43 restrain the c-Met selectively, with the IC50 values of 16 nM, which showed equal activity to Foretinib (14 nM) and better than the compound 5 (90 nM). Moreover, AO and Annexin V/PI staining and docking studies were carried out.

Discovery of thinopyrimidine-triazole conjugates as c-Met targeting and apoptosis inducing agents.

Five series of N-methylpicolinamide moiety and thienopyrimidine moiety bearing triazole (21-26, 27-34, 35-41, 42-47 and 48-54) were designed and synthesized. And all the target compounds were evaluated for the IC50 values against three cancer cell lines (A549, HepG2 and MCF-7) and some selected compounds (43, 49 and 52) were further evaluated for the activity against c-Met, Flt-3, VEGFR-2, c-Kit and EGFR kinases. Moreover, SARs and docking studies indicated that thieno[3,2-d]pyrimidine bearing triazole moiety was privileged structure for the activity. Especially, the Cl atom on the 4-C position of aryl group showed the best activity. The most promising compound 49 showed 3.7-5.4-fold more activity than the lead drug Foretinib against A549, HepG2 and MCF-7 cell lines, with the IC50 values of 0.9 ±â€¯0.1 µM, 0.5 ±â€¯0.1 µM and 1.1 ±â€¯0.2 µM, respectively. And The experiments of enzyme-based showed that 49 inhibitor the c-Met selectively, with the IC50 values of 16 nM, which showed equal activity to Foretinib (14 nM). What's more, According to the result of AO single staining and Annexin V/PI staining, it's claimed that the 49 could induce late apoptosis of HepG2 cells and by a concentration-dependent manner.