Design and synthesis of a novel class EGFR/HER2 dual inhibitors containing tricyclic oxazine fused quinazolines scaffold

Two series of novel tricyclic oxazine and oxazepine fused quinazolines have been designed, synthesized and evaluated for their inhibitory activity against EGFR and HER2. Structure-activity relationship (SAR) of these compounds was discussed. From the SAR studies, we found that intramolecular cyclization which possessed a functional Michael acceptor group can enhance the antitumor activities. Compounds 1e and 1h were identified as lead compounds which displayed almost 3–4 times more potent inhibition of EGFR and HER2 than the approved drug lapatinib. The satisfactory physicochemical properties of these compounds were also supported by ACD labs. The results presented here will promote the development of newer dual inhibitors of EGFR and HER2.     

Identification of novel 4-anilinoquinazoline derivatives as potent EGFR inhibitors both under normoxia and hypoxia

A novel series of 4-anilinoquinazoline derivatives (19a–19t) were designed and synthesized through incorporation of the 2-nitroimidazole moiety into the 4-anilinoquinazoline scaffold of EGFR inhibitors. The most promising compound 19h displayed potent EGFR inhibitory activity with the IC₅₀ value of 0.47 nM. It also strongly suppressed the proliferation of A549 and HT-29 cells with sub-micromolar IC₅₀ values both under normoxia and hypoxia, which were several folds more potent than gefitinib and erlotinib. Further reductive mimic investigation revealed that 19h could be reductive activated under hypoxia and was fully consistent with the results of cell apoptotic assay and in vitro metabolism evaluation. Our results suggest that the incorporation of hypoxia-activated moiety into EGFR inhibitor scaffold might be a tractable strategy to overcome the tumor hypoxia.     

Design,synthesis, biological evaluation,QSAR analysis and molecular modelling of new thiazol-benzimidazoles as EGFR inhibitors

Heterocyclic rings such as thiazole and benzimidazole are considered as privileged structures, since they constitute several FDA-approved drugs for cancer treatment. In this work, a new set of 2-(2-(substituted) hydrazinyl)-4-(1-methyl-1H-benzo[d]imidazol-2-yl) thiazoles 4a-q were designed as epidermal growth factor receptor (EGFR) inhibitors and synthesized using concise synthetic methods. The new target compounds have been evaluated in vitro for their suppression activity against EGFR TK. Compounds 4n, 4h, 4i, 4a and 4d exhibited significant potency in comparison with erlotinib which served as a reference drug (IC50, 71.67–152.59 nM; IC50 erlotinib, 152.59 nM). Furthermore, MTT assay revealed that compounds 4j, 4a, 4f, 4h, 4n produced the most promising cytotoxic potency against the human breast cancer cell line (MCF-7) (IC50; 5.96–11.91 µM; IC50 erlotinib; 4.15 µM). Compound 4a showed promising activity as EGFR TK inhibitor as well as anti-breast cancer agent. In addition, 4a induced apoptotic effect and cell cycle arrest at G2/M phase preventing the mitotic cycle in MCF-7 cells. Moreover, 4a upregulated the oncogenic parameters; caspase-3, p53, Bax/Bcl-2 as well as it inhibited the level of PARP-1 enzyme. QSAR study was carried out for the new derivatives and it revealed the goodness of the models. Furthermore, molecular docking studies represented the binding modes of the promising compounds in the active pocket of EGFR.     

Design,synthesis, and biological evaluation of novel 1-oxo-1,2,3,4-tetrahydropyrazino[1,2-a]indole-3-carboxamide analogs in MCF-7 and MDA-MB-468 breast cancer cell lines

A series of novel 1-oxo-1,2,3,4-tetrahydropyrazino[1,2-a]indole-3-carboxamide analogs were designed and synthesized for developing pyrazinoindolone scaffolds as anti-breast cancer agents. Compounds 1h and 1i, having a furan-2-yl-methylamide and benzylamide group, respectively, exhibited more potent cytotoxicity in MDA-MB-468 triple-negative breast cancer (TNBC) cells than compounds possessing aliphatic groups. Compounds 2a and 2b, as (R)-enantiomers of 1h and 1i, also had inhibitory activity against MDA-MB-468 cells. Moreover, analogs (3a–b and 3d–e) bearing a benzyl group at the N-2 position showed more potent activity than gefitinib, as a potent EFGR-TK inhibitor. Especially, compound 3a exhibited selective cytotoxic activity against MDA-MB-468 cells; it also had a synergistic effect in combination with gefitinib against MDA-MB-468 cells. In addition, we confirmed that compounds 3a and 3d inhibit phosphorylation of Akt in MDA-MB-468 cells using western blot analysis. Therefore, these 1-oxo-1,2,3,4-tetrahydropyrazino[1,2-a]indole-3-carboxamide analogs may be helpful for investigating new anti-TNBC agents.     

Design,synthesis and anticancer evaluation of thieno[2,3-d]pyrimidine derivatives as dual EGFR/HER2 inhibitors and apoptosis inducers

Deregulation of many kinases is directly linked to cancer development and the tyrosine kinase family is one of the most important targets in current cancer therapy regimens. In this study, we have designed and synthesized a series of thieno[2,3-d]pyrimidine derivatives as an EGFR and HER2 tyrosine kinase inhibitors. All the synthesized compounds were evaluated in vitro for their inhibitory activities against EGFR^WT; and the most active compounds that showed promising IC₅₀ values against EGFR^WT were tested in vitro for their inhibitory activities against mutant EGFR^T790M and HER2 kinases. Moreover, the antitumor activities of these compounds were tested against four cancer cell lines (HepG2, HCT-116, MCF-7 and A431). Compounds 13g, 13h and 13k exhibited the highest activities against the examined cell lines with IC₅₀ values ranging from 7.592 ± 0.32 to 16.006 ± 0.58 µM comparable to that of erlotinib (IC₅₀ ranging from 4.99 ± 0.09 to 13.914 ± 0.36 µM). Furthermore, the most potent antitumor agent (13k) was selected for further studies to determine its effect on the cell cycle progression and apoptosis in MCF-7 cell line. The results indicated that this compound arrests G₂/M phase of the cell cycle and it is a good apoptotic agent. Finally, molecular docking studies showed a good binding pattern of the synthesized compounds with the prospective target, EGFR^WT and EGFR^T790M.     

Design,synthesis and evaluation of novel hybrids between 4-anilinoquinazolines and substituted triazoles as potent cytotoxic agents

In this research several series of novel dioxygenated ring fused 4-anilinoquinazolines (10a-d) and 4-anilinoquinazoline-substituted triazole hybrid compounds (11–14) have been designed and synthesized. Their biological significance was highlighted by evaluating in vitro for anticancer activities, wherein several compounds displayed excellent activity specifically against three human cancer cell lines (KB, epidermoid carcinoma; HepG2, hepatoma carcinoma; SK-Lu-1, non-small lung cancer). Especially, compound 13a exhibited up to 100-fold higher cytotoxicity in comparison with erlotinib. Docking the most cytotoxic compounds (11d, 13a, 13b, and 14c) into the ATP binding site of different EGFR tyrosine kinase domains was perfomed to predict the analogous binding mode of these compounds to the EGFR targets.     

Synthesis and docking studies of novel antitumor benzimidazoles

In this work, the benzimidazole-pyrrole conjugates 6a–h and benzimidazole-tetracycles conjugates 12–14 were prepared. The cytotoxicity of the compounds 3, 4a–h, 6a–h, 8, 10 and 12–14 was tested against lung cancer cell line A549. Compound 6b exhibited higher activity than the bis-benzoxazole natural product (UK-1), the standard. The tested 4g,h, 6a–h, 10 and 12–14 exhibited remarkable cytotoxicity activity against breast cancer cell line MCF-7 with higher activity than tamoxifen. Furthermore, compound 4h was found to be also more potent than doxurubicin. The antitumor promotion activity of synthesized compounds 4g,h, 6a–h, 10 and 12–14 has been estimated by studying their possible inhibitory effects on EBV-EA activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). Among the studied compounds, the inhibitory activities of compounds 8, 13 and 14 demonstrated strong inhibitory effects on the Epstein–Barr virus early antigen (EBV-EA) activation without showing any cytotoxicity on the Raji cells and their effects being stronger than that of a representative control, oleanolic acid.Moreover, the molecular docking of the new compounds into plasminogen activator (uPA) receptor has been in correlation with the antitumor activity. All synthesized compounds 3, 4a–h, 6a–h, 8, 10 and 12–14 were docked into same groove of the binding site of the native co-crystalized (4-iodobenzo[b]thiophene-2-carboxamidine) ligand (PDB code:1c5x) for activity explaination. Compounds 4h, 6b and 13, giving the best docking results, were further studied to estimate their effect on the level of uPA using AssayMax human urokinase (uPA) ELISA kit. In case of A549 cell line, compound 6 exhibited similar activity to MMC, and for MCF-7 cell line, compound 4h exhibited similar activity to doxorubicin, in inhibiting the expression of uPA.     

Synthesis,biological evaluation and molecular docking studies of amide-coupled benzoic nitrogen mustard derivatives as potential antitumor agents

A series of amide-coupled benzoic nitrogen mustard derivatives as potential EGFR and HER-2 kinase inhibitors were synthesized and reported for the first time. Some of them exhibited significant EGFR and HER-2 inhibitory activity. Of all the studied compounds, compounds 5b and 5t exhibited the most potent inhibitory activity, which was comparable to the positive control erlotinib. Docking simulation was performed to position compounds 5b and 5t into the EGFR active site to determine the probable binding model. Antiproliferative assay results indicated that some of the benzoic nitrogen mustard derivatives possessed high antiproliferative activity against MCF-7. In particular, compounds 5b and 5t with potent inhibitory activity in tumor growth inhibition may function as potential antitumor agents.     

Synthesis,antimicrobial, and mosquito larvicidal activity of 1-aryl-4-methyl-3,6-bis-(5-methylisoxazol-3-yl)-2-thioxo-2,3,6,10b-tetrahydro-1H-pyrimido[5,4-c]quinolin-5-ones

A series of 1-aryl-4-methyl-3,6-bis-(5-methylisoxazol-3-yl)-2-thioxo-2,3,6,10b-tetrahydro-1H-pyrimido[5,4-c]quinolin-5-ones (6a–h) have been synthesized by cyclization of ethyl-3-aryl-4-(2-chlorophenyl)-6-methyl-1-(5-methylisoxazol-3-yl)-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates 4a–h with 3-amino-5-methylisoxazole 5. Compounds 4a–h were obtained by Biginelli reaction, by condensation of aromatic aldehyde 1, ethyl acetoacetate 2, and isoxazolyl thioureas 3 in a one-pot reaction catalyzed by ceric ammonium nitrite (CAN). Compounds 6a–h were tested for their antibacterial and antifungal activities against various bacterial and fungal strains. The results showed that these compounds exhibited good antibacterial and antifungal activity compared with that of standard antibiotics. Mosquito larvicidal activity of the newly synthesized compounds 6a–h is also studied against fourth instar larvae Culex quinquefasciatus. Some of the compounds are proved to be lethal for mosquito larvae.     

Toward discovery of mutant EGFR inhibitors; Design,synthesis and in vitro biological evaluation of potent 4-arylamino-6-ureido and thioureido-quinazoline derivatives

A new series of 4-anilinoquinazolines with C-6 ureido and thioureido side chains and various substituents at the C-4 anilino moiety was designed, synthesized and evaluated as wild type (WT) and mutant EGFR inhibitors. Most of the compounds inhibited EGFR kinase wild type (EGFR WT) with IC₅₀ values in the low nanomolar range (<0.495–9.05 nM) and displayed more potent cytotoxic effect in BaF/3 expressing EGFR WT than reference compound gefitinib. The anti-proliferative effect of all synthesized compounds against gefitinib insensitive double mutant cell lines Ba/F3 expressing Del19/T790M and Ba/F3 expressing L858R/T790M were assayed. Compounds 4d, 6f, 7e showed significant inhibition (IC₅₀ = 1.76–2.38 μM) in these mutant lines and significant Her2 enzyme inhibition (IC₅₀ = 19.2–40.6 nM) compared to lapatinib (60.1 nM). The Binding mode of compounds 6d, 6f, 7a, 7b and 8b were demonstrated. Furthermore, growth inhibition against gefitinib insensitive cell lines PC9-GR4 (Del19/T790M) were tested, compounds 6f and 7e showed about eight and three folds respectively greater potency than gefitinib. Our structure–activity relationships (SAR) studies suggested that presence of ethyl piperidino urea/thiourea at 6-position and bulky group of (3-chloro-4-(3-fluorobenzyloxy)phenyl)amino at 4-position of quinazoline may serve as promising scaffold for developing inhibitors against wild type and mutant EGFR.     

Discovery of new quinazoline derivatives as irreversible dual EGFR/HER2 inhibitors and their anticancer activities – Part 1

Overexpression of EGFR and HER2 are observed in many breast, ovarian, colon and prostate cancers. The second and third generation irreversible EGFR/HER2 dual kinase inhibitors became popular after the approval of Afatinib by FDA to overcome the mutation related problem. To find efficacious drug candidates, a series of novel quinazoline derivatives were designed, synthesized and evaluated as dual EGFR/HER2 tyrosine kinase (TK) inhibitors. Selected twenty four compounds were reported here with significant inhibitory activities against EGFR/HER2 tyrosine kinases. Several compounds showed nanomolar IC₅₀ values. In vitro studies of quinazoline derivatives were done on NCI-H1975, HCC827, A431, MDA MB-453 cell lines. The compounds 1a, 1d and 1v were found more potent compared to standard drug afatinib. In vivo efficacy study of 1d on nude mice NCI-H1975 tumour xenograft model was discussed.     

Novel inhibitors of epidermal growth factor receptor: (4-(Arylamino)-7H-pyrrolo[2,3-d]pyrimidin-6-yl)(1H-indol-2-yl)methanones and (1H-indol-2-yl)(4-(phenylamino)thieno[2,3-d]pyrimidin-6-yl)methanones

Several members of the quinazoline class of known tyrosine kinase inhibitors are approved anticancer agents, often showing selectivity for receptors of the HER/ErbB-family. Combining structural elements of this class with the bisindolylmethanone-structure led to a series of novel compounds. These compounds inhibited EGFR in the nanomolar range. Moreover, inhibition of EGFR autophosphorylation in intact A431 cells was shown, with IC₅₀ values ranging form 0.3–1 μM for compound 42, and 0.1–0.3 μM for 45. In a panel of 42 human tumor cell lines the sensitivity profile of the novel compounds was shown to be similar to that of the quinazoline class of tyrosine kinase inhibitors lapatinib and erlotinib (Tarceva®).     

Dual EGFR/HER2 inhibitors and apoptosis inducers: New benzo[g]quinazoline derivatives bearing benzenesulfonamide as anticancer and radiosensitizers

Dual targeting of EGFR and HER2 is a proven anticancer strategy for the treatment of solid tumors. An array of new N-substituted-2-(4-oxo-3-(4-sulfamoylphenyl)-3,4-dihydrobenzo[g]quinazolin-2-ylthio) acetamides 5–18 were designed and synthesized from the starting compound 4-(2-mercapto-4-oxobenzo[g]quinazolin-3(4H)-yl) benzenesulfonamide 4. The targeted compounds were screened for their cytotoxic activity against MDA-MB-231 breast cancer cell line. The IC₅₀ of all the compounds were in the range of 0.36–40.90 µM. The percentage inhibition towards EGFR was measured and found to be in the range of 63.00–16.90 %. The most potent compounds 5, 9, 15, 17 and 18 were further screened for their activity against both EGFR and HER2 receptors. The compounds showed IC₅₀ in the range of 0.64–1.81 µM for EGFR and 1.13–2.21 µM for HER2, in comparison to erlotinib, the reference drug. Compound 17, the most potent towards EGFR in this series, undergoes cell cycle analysis and was found to arrest the cycle at the G2/M phase. Measurement of the cytotoxicity of compound 17 against normal breast cell line showed mild cytotoxic activity. The most potent compounds were subjected to a single dose of 8 Gy of γ-radiation and the cytotoxicity of the tested compounds was found to increase after irradiation, thus proving the synergistic effect of γ-irradiation. Molecular docking was adopted for all the synthesized compounds to confirm their mechanism of action.     

Synthesis and evaluation of novel 7-azaindazolyl-indolyl-maleimide derivatives as antitumor agents and protein kinase C inhibitors

A series of novel 7-azaindazolyl-indolyl-maleimides were synthesized and evaluated for their antiproliferative activity in vitro against various human cancer cell lines and protein kinase C inhibitory activity. Compounds 8a–c, 8e and 14a were the most promising compounds against K562, A549, ECA-109, KB and SMMC-7721 cell lines in vitro. Compounds 9a–j showed moderate PKC inhibition. Further mechanism of action studies revealed that the antiproliferative activity of compound 8b in KB cells might involve the mitochondria-mediated apoptosis pathway.     

Synthesis and potential antitumor activity of 7-(4-substituted piperazin-1-yl)-4-oxoquinolines based on ciprofloxacin and norfloxacin scaffolds: in silico studies

The potential antitumor activities of a series of 7-(4-substituted piperazin-1-yl)fluoroquinolone derivatives (1–14a,b) using ciprofloxacin and norfloxacin as scaffolds are described. These compounds exhibit potent and broad spectrum antitumor activities using 60 human cell lines in addition to the inherent antibacterial activity. Compounds 1a, 2a, 3b, 6b and 7a were found to be the most potent, while 2b, 5b, and 6a were found to have an average activity. The results of this study demonstrated that compounds 1a, 2a, 3b, 6b and 7a (mean GI₅₀; 2.63–3.09?µM) are nearly 7-fold more potent compared with the positive control 5-fluorouracil (mean GI₅₀; 22.60?µM). More interestingly, compounds 1a, 2a, 3b, 6b and 7a have an almost antitumor activity similar to gefitinib (mean GI₅₀; 3.24?µM) and are nearly 2-fold more potent compared to erlotinib (mean GI₅₀; 7.29?µM). In silico study and ADME-Tox prediction methodology were used to study the antitumor activity of the most active compounds and to identify the structural features required for antitumor activity.     

Imidazo[1,2-a]pyridines linked with thiazoles/thiophene motif through keto spacer as potential cytotoxic agents and NF-κB inhibitors

A series of new imidazo[1,2-a]pyridine linked with thiazole/thiophene motif through a keto spacer were synthesized and tested for their cytotoxic potential against three human cancer cell lines including A549, HeLa and U87-MG using MTT assay. Compounds A2, A3, A4, C1 and C2 showed cytotoxicity against all the three cell lines. The selectivity index for compound A4 for A549 and HeLa cells was comparable to that of doxorubicin. Among the synthesized compounds, B5 showed the maximum inhibition of NF-κB activity as ascertained by NF-κB reporter assay (IC₅₀?=?6.5?±?0.6?µM). Treatment of NCI-H23 cells (EGFR overexpressed, KRAS G12V mutant) with erlotinib and gefitinib along with compounds A4 and B5 indicated synergistic and additive potential of combination therapy.     

Benzo[g]quinazolin-based scaffold derivatives as dual EGFR/HER2 inhibitors

Targeting EGFR has proven to be beneficial in the treatment of several types of solid tumours. So, a series of novel 2-(4-oxo-3-(4-sulfamoylphenyl)-3,4-dihydrobenzo[g]quinazolin-2-ylthio)-N-substituted acetamide 5–19 were synthesised from the starting material 4-(2-mercapto-4-oxobenzo[g]quinazolin-3(4H)-yl) benzenesulfonamide 4, to be evaluated as dual EGFR/HER2 inhibitors. The target compounds 5–19, were screened for their cytotoxic activity against A549 lung cancer cell line. The percentage inhibition of EGFR enzyme was measured and compared with erlotinib as the reference drug. Compounds 6, 8, 10, and 16 showed excellent EGFR inhibitory activity and were further selected for screening as dual EGFR/HER2 inhibitors. The four selected compounds showed IC₅₀ ranging from 0.009 to 0.026?µM for EGFR and 0.021 to 0.069?µM for the HER2 enzyme. Compound 8 was found to be the most potent in this study with IC₅₀ 0.009 and 0.021?µM for EGFR and HER2, respectively.     

Design and synthesis of pyrrolo[3,2-d]pyrimidine HER2/EGFR dual inhibitors: Improvement of the physicochemical and pharmacokinetic profiles for potent in vivo anti-tumor efficacy

During the course of our studies on a novel HER2/EGFR dual inhibitor (TAK-285), we found an alternative potent pyrrolo[3,2-d]pyrimidine compound (1a). To enhance the pharmacokinetic (PK) profile of this compound, we conducted chemical modifications into its N-5 side chain and conversion of the chemically modified compounds into their salts. Among them, 2cb, the tosylate salt of compound 2c, showed potent HER2/EGFR kinase inhibitory activity (IC₅₀: 11/11 nM) and cellular growth inhibitory activity (BT-474 cell GI₅₀: 56 nM) with a good drug metabolism and PK (DMPK) profile. Furthermore, 2cb exhibited significant in vivo antitumor efficacy in both mouse and rat xenograft models with transplanted 4-1ST gastric cancer cell lines (mouse, T/C = 0%, 2cb po bid at 100 mg/kg; rat, T/C: -1%, 2cb po bid at 25 mg/kg).     

Four-membered heterocycles-containing 4-anilino-quinazoline derivatives as epidermal growth factor receptor (EGFR) kinase inhibitors

We report herein the design and synthesis of novel azaspirocycle or azetidine substituted 4-anilinoquinazoline derivatives. The EGFR inhibitory activities and in vitro antitumor potency of these newly synthesized compounds against two lung cancer cell lines HCC827 and A549 were evaluated. Most of the target compounds possess good inhibitory potency. In particular, compounds 21g with 2-oxa-6-azaspiro[3.4]octane substituent was found to possess higher EGFR inhibitory activities and similar antitumor potency comparing to the lead compound gefitinib with improved water solubility.     

Synthesis and investigation of novel 6-(1,2,3-triazol-4-yl)-4-aminoquinazolin derivatives possessing hydroxamic acid moiety for cancer therapy

By merging the critical pharmacophore of EGFR/HER2 and HDAC inhibitors into one compound, a novel series of EGFR, HER-2, and HDAC multitarget inhibitors were synthesized. Compounds 9a–l contained 4-anilinoquinazolines with C-6 triazole-linked long alkyl chains of hydroxamic acid and displayed excellent inhibition against these enzymes (compound 9d exhibited the best inhibitory potency on wild-type EGFR, HDAC1, and HDAC6 with IC₅₀ values 0.12 nM, 0.72 nM and 3.2 nM individually). Furthermore, compounds 9b and 9d potently inhibited proliferation of five human cancer cell lines (with IC₅₀ values between 0.49 and 8.76 μM). Further mechanistic study revealed that compound 9d also regulated the phosphorylation of EGFR and HER2 and histone H3 hyperacetylation on the cellular level and induced remarkable apoptosis in BT-474 cells. Therefore, our study suggested that a system network-based multi-target drug design strategy might provided an alternate drug design method, by taking into account the synergy effect of EGFR, HER-2 and HDAC.