Mediating EGFR-TKI Resistance by VEGF/VEGFR Autocrine Pathway in Non-Small Cell Lung Cancer

Recent development of VEGFR small molecule inhibitors as anticancer agents: A patent review (2021-2023)

VEGFR, a receptor tyrosine kinase inhibitor (TKI), is an important regulatory factor that promotes angiogenesis and vascular permeability. It plays a significant role in processes such as tumor angiogenesis, tumor cell invasion, and metastasis. VEGFR is mainly composed of three subtypes: VEGFR-1, VEGFR-2, and VEGFR-3. Among them, VEGFR-2 is the crucial signaling receptor for VEGF, which is involved in various pathological and physiological functions. At present, VEGFR-2 is closely related to a variety of cancers, such as non-small cell lung cancer (NSCLC), Hepatocellular carcinoma, Renal cell carcinoma, breast cancer, gastric cancer, glioma, etc. Consequently, VEGFR-2 serves as a crucial target for various cancer treatments. An increasing number of VEGFR inhibitors have been discovered to treat cancer, and they have achieved tremendous success in the clinic. Nevertheless, VEGFR inhibitors often exhibit severe cytotoxicity, resistance, and limitations in indications, which weaken the clinical therapeutic effect. In recent years, many small molecule inhibitors targeting VEGFR have been identified with anti-drug resistance, lower cytotoxicity, and better affinity. Here, we provide an overview of the structure and physiological functions of VEGFR, as well as some VEGFR inhibitors currently in clinical use. Also, we summarize the in vivo and in vitro activities, selectivity, structure-activity relationship, and therapeutic or preventive use of VEGFR small molecule inhibitors reported in patents in the past three years (2021-2023), thereby presenting the prospects and insights for the future development of targeted VEGFR inhibitors.

Management of Treatment Resistance in Patients With Advanced Epidermal Growth Factor Receptor-Mutated Lung Cancer: Personalization, Parsimony, and Partnership

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice.Patients with epidermal growth factor receptor (EGFR)-mutated advanced non-small-cell lung cancer represent a distinct subgroup of individuals who can experience initially tolerable and durable effects with first-line EGFR-directed tyrosine kinase inhibitors. Unfortunately, acquired treatment resistance and cancer progression within the CNS are inevitable during the disease course and present a challenging transition in the care continuum. Next-line therapies generally require combinations of drugs and afford nuanced differences in clinical outcomes relative to the treatment experience, toxicity profile, and quality of life. Therapeutic stratification and modulation thus require further personalization and partnership with patients to identify key clinical, molecular, and human-specific factors to best guide optimal care.

PIK3CA mutation as an acquired resistance driver to EGFR-TKIs in non-small cell lung cancer: Clinical challenges and opportunities

Epithelial growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have significantly enhanced the treatment outcomes in non-small cell lung cancer (NSCLC) patients harboring EGFR mutations. However, the occurrence of acquired resistance to EGFR-TKIs is an unavoidable outcome observed in these patients. Disruption of the PI3K/AKT/mTOR signaling pathway can contribute to the emergence of resistance to EGFR TKIs in lung cancer. The emergence of PIK3CA mutations following treatment with EGFR-TKIs can lead to resistance against EGFR-TKIs. This review provides an overview of the current perspectives regarding the involvement of PI3K/AKT/mTOR signaling in the development of lung cancer. Furthermore, we outline the state-of-the-art therapeutic strategies targeting the PI3K/AKT/mTOR signaling pathway in lung cancer. We highlight the role of PIK3CA mutation as an acquired resistance mechanism against EGFR-TKIs in EGFR-mutant NSCLC. Crucially, we explore therapeutic strategies targeting PIK3CA-mediated resistance to EGFR TKIs in lung cancer, aiming to optimize the effectiveness of treatment.

Epigenetic-based combination therapy and liposomal codelivery overcomes osimertinib-resistant NSCLC via repolarizing tumor-associated macrophages

Osimertinib (Osi) is widely used as a first-line treatment for non-small cell lung cancer (NSCLC) with EGFR mutations. However, the majority of patients treated with Osi eventually relapse within a year. The mechanisms of Osi resistance remain largely unexplored, and efficient strategies to reverse the resistance are urgently needed. Here, we developed a lactoferrin-modified liposomal codelivery system for the combination therapy of Osi and panobinostat (Pan), an epigenetic regulator of histone acetylation. We demonstrated that the codelivery liposomes could efficiently repolarize tumor-associated macrophages (TAM) from the M2 to M1 phenotype and reverse the epithelial-mesenchymal transition (EMT)-associated drug resistance in the tumor cells, as well as suppress glycolysis, lactic acid production, and angiogenesis. Our results suggested that the combination therapy of Osi and Pan mediated by liposomal codelivery is a promising strategy for overcoming Osi resistance in NSCLC.

Identification of novel ureido benzothiophenes as dual VEGFR-2/EGFR anticancer agents

Presently, dual-targeting by a single small molecule stands out as a fruitful cancer-fighting strategy. Joining the global effort to fight cancer, a leading cause of death worldwide, we report in this study a novel set for benzothiophene-based aryl urea derivatives as potential anti-proliferative candidates endowed with dual VEGFR-2/EGFR inhibitory activities. The prepared ureido benzothiophenes 6a-r have been evaluated for their anticancer action on a panel of tumor cell lines, namely PanC-1, MCF-7, and HepG2 cells. Most newly synthesized benzo[b]thiophene ureas disclosed effective cytotoxic activities against the examined cancer cell lines. In particular, compound 6q, with an appended 4-trifluoromethoxy group on the terminal phenyl ring, exhibited the most significant cytotoxic activity in MCF-7 with IC50 3.86 ± 0.72 ug/mL; IC50 of 3.65 ± 0.18 ug/ml in PanC-1 cell line and an IC50 of 4.78 ± 0.06 ug/ml in HepG2. After that, derivatives that exhibited the most potent cytotoxic activities (6g, 6j, 6q, and 6r) were further evaluated as VEGFR-2 and EGFR inhibitors. Fortunately, they displayed low nanomolar IC50 values against both enzymes, where compound 6q emerged to possess superior inhibitory effects towards both EGFR and VEGFR-2 with IC50 46.6 nM and 11.3 nM simultaneously compared to the reference medications Erlotinib and Sorafenib, respectively. The docked structure of 6q within the catalytic region of VEGFR-2 and EGFR kinases was acquired and studied so that we could investigate potential binding mechanisms for the target ureido benzothiophenes. Hence, the benzothiophene-based aryl urea scaffold has great potential for advancing the development of highly effective dual inhibitors targeting both EGFR and VEGFR-2, which can serve as effective candidates for anticancer therapy.

The cell line models to study tyrosine kinase inhibitors in non-small cell lung cancer with mutations in the epidermal growth factor receptor: A scoping review

Non-Small Cell Lung Cancer (NSCLC) represents ∼85% of all lung cancers and ∼15-20% of them are characterized by mutations affecting the Epidermal Growth Factor Receptor (EGFR). For several years now, a class of tyrosine kinase inhibitors was developed, targeting sensitive mutations affecting the EGFR (EGFR-TKIs). To date, the main burden of the TKIs employment is due to the onset of resistance mutations. This scoping review aims to resume the current situation about the cell line models employed for the in vitro evaluation of resistance mechanisms induced by EGFR-TKIs in oncogene-addicted NSCLC. Adenocarcinoma results the most studied NSCLC histotype with the H1650, H1975, HCC827 and PC9 mutated cell lines, while Gefitinib and Osimertinib the most investigated inhibitors. Overall, data collected frame the current advancement of this topic, showing a plethora of approaches pursued to overcome the TKIs resistance, from RNA-mediated strategies to the innovative combination therapies.

Advances and challenges in the treatment of lung cancer

Lung cancer accounts for a relatively high proportion of malignant tumors. As the most prevalent type of lung cancer, non-small cell lung cancer (NSCLC) is characterized by high morbidity and mortality. Presently, the arsenal of treatment strategies encompasses surgical resection, chemotherapy, targeted therapy and radiotherapy. However, despite these options, the prognosis remains distressingly poor with a low 5-year survival rate. Therefore, it is urgent to pursue a paradigm shift in treatment methodologies. In recent years, the advent of sophisticated biotechnologies and interdisciplinary integration has provided innovative approaches for the treatment of lung cancer. This article reviews the cutting-edge developments in the nano drug delivery system, molecular targeted treatment system, photothermal treatment strategy, and immunotherapy for lung cancer. Overall, by systematically summarizing and critically analyzing the latest progress and current challenges in these treatment strategies of lung cancer, we aim to provide a theoretical basis for the development of novel drugs for lung cancer treatment, and thus improve the therapeutic outcomes for lung cancer patients.

Exploring the promising potential of induced pluripotent stem cells in cancer research and therapy

The advent of iPSCs has brought about a significant transformation in stem cell research, opening up promising avenues for advancing cancer treatment. The formation of cancer is a multifaceted process influenced by genetic, epigenetic, and environmental factors. iPSCs offer a distinctive platform for investigating the origin of cancer, paving the way for novel approaches to cancer treatment, drug testing, and tailored medical interventions. This review article will provide an overview of the science behind iPSCs, the current limitations and challenges in iPSC-based cancer therapy, the ethical and social implications, and the comparative analysis with other stem cell types for cancer treatment. The article will also discuss the applications of iPSCs in tumorigenesis, the future of iPSCs in tumorigenesis research, and highlight successful case studies utilizing iPSCs in tumorigenesis research. The conclusion will summarize the advancements made in iPSC-based tumorigenesis research and the importance of continued investment in iPSC research to unlock the full potential of these cells.

Clinicopathological impact of VEGFR2 and VEGF-C in patients with EGFR-major mutant NSCLC receiving osimertinib

BACKGROUND

Vascular endothelial growth factor (VEGF) has been identified as one of the resistant mechanisms to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs). However, the relationship between the efficacy of osimertinib and protein expression of VEGF family members in patients with advanced non-small cell lung cancer (NSCLC) harboring EGFR mutations remains unclear.

METHODS

A total of 76 patients with advanced NSCLC with EGFR major mutations (del19 or L858R) receiving first-line osimertinib were eligible as the osimertinib (Osi) group, whereas 43 patients receiving first- or second-generation EGFR-TKIs were compared with the control group. The expression of vascular endothelial growth factor receptor 2 (VEGFR2) and vascular endothelial growth factor C (VEGF-C) in the tumor specimens was analyzed using immunohistochemistry.

RESULTS

VEGFR2 and VEGF-C were highly expressed in 65.8% and 51.3% of patients, respectively, in the Osi group, and 69.7% and 76.7%, respectively, in the control group. High VEGFR2 and VEGF-C levels were significantly associated with poor performance status (PS) and female sex, respectively. In the Osi group, patients with co-high expression of VEGFR2 and VEGF-C showed significantly worse progression-free survival (PFS) and overall survival (OS) than those without co-high expression. In del19, VEGFR2 was a significant predictor of PFS and OS and independent predictor of OS in multivariate analysis. In L858R, co-high expression of VEGFR2 and VEGF-C was identified as a significant predictor of PFS and OS and independent predictor of PFS.

CONCLUSION

VEGFR2 and VEGF-C are highly expressed in EGFR-mutant NSCLC cells. Increased expression of VEGFR2 was identified as a significant prognostic factor in patients with EGFR del19 mutation who received osimertinib, whereas co-high expression of VEGFR2 and VEGF-C was a significant predictor for those with EGFR L858R mutation.

Inhibition of VEGFR2 and EGFR signaling cooperatively suppresses the proliferation of oral squamous cell carcinoma

BACKGROUND

Epidermal growth factor receptor (EGFR) is frequently overexpressed in oral squamous cell carcinoma (OSCC), and EGFR-targeting therapeutics have been widely employed to treat patients with a variety of carcinomas including OSCC. Here, we aimed to investigate alternative signaling for OSCC survival under the disruption of EGFR signaling.

METHODS

OSCC cell lines, namely HSC-3 and SAS, were utilized to investigate how EGFR disruption affects cell proliferation. Gene set enrichment analysis was performed to examine how EGFR disruption affects oncogenic signaling in OSCC cells. Disruption of KDR gene was performed using CRISPR/Cas9 techniques. A VEGFR inhibitor, vatalanib was used to research the impact of VEGFR inhibition on OSCC survival.

RESULTS

EGFR disruption significantly decreased the proliferation and oncogenic signaling including Myc and PI3K-Akt, in OSCC cells. Chemical library screening assays revealed that VEGFR inhibitors continued to inhibit the proliferation of EGFR-deficient OSCC cells. In addition, CRISPR-mediated disruption of KDR/VEGFR2 retarded OSCC cell proliferation. Furthermore, combined erlotinib-vatalanib treatment exhibited a more potent anti-proliferative effect on OSCC cells, compared to either monotherapy. The combined therapy effectively suppressed the phosphorylation levels of Akt but not p44/42.

CONCLUSION

VEGFR-mediated signaling would be an alternative signaling pathway for the survival of OSCC cells under the disruption of EGFR signaling. These results highlight the clinical application of VEGFR inhibitors in the development of multi-molecular-targeted therapeutics against OSCC.

Low‑dose anlotinib combined with EGFR‑TKI can be used as an alternative for EGFR‑TKI‑resistant non‑small cell lung cancer in elderly patients

The current treatment options for epidermal growth factor receptor (EGFR) mutation-positive lung cancer in the elderly with tyrosine kinase inhibitor (TKI) resistance are limited. Although chemotherapy combined with vascular endothelial growth factor inhibitors significantly improves progression-free survival (PFS) in TKI-resistant patients, it often cannot be tolerated in elderly patients, leading to treatment failure. Anlotinib is a small molecule inhibitor made in China. The application of low-dose anlotinib in elderly patients with TKI-resistant lung cancer deserves further investigation. A total of 48 elderly patients with non-small cell lung cancer (NSCLC) were enrolled to evaluate the efficacy of anlotinib combined with continuous EGFR-TKI vs. anlotinib monotherapy in patients with acquired EGFR-TKI resistance. Anlotinib was administered at a dose of 6-8 mg per day, lower than the normal dose and known as a low dose, which is well tolerated in elderly patients. There were 25 cases in the combination group and 23 cases in the anlotinib monotherapy group. The primary endpoint of the present study was PFS, and the secondary endpoints were overall survival (OS), response rate and toxicity. The median PFS (mPFS) was significantly longer in the combination group than that in the anlotinib monotherapy group: 6.0 months [95% confidence interval (CI), 4.35-7.65] compared with 4.0 months (95% CI, 3.38-4.62) (P=0.002). Analysis of the subgroups showed similar trends in results. The median OS was 32 months (95% CI, 22.04-41.96) in the combination group and 28 months (95% CI, 27.13-28.87) in the anlotinib monotherapy group (P=0.217). According to stratification analysis, second-line treatment with anlotinib combined with EGFR-TKI resulted in a better mPFS than third-line treatment (7.5 vs. 3.7 months, HR=3.477; 95% CI, 1.117-10.820; P=0.031). In the combination group, patients with gradual/local progression after EGFR-TKI failure had a longer mPFS than those with dramatic progression (7.5 vs. 6.0 months, HR=5.875; 95% CI, 1.414-10.460; P=0.015). Multivariate analyses showed that continuous EGFR-TKI combined with anlotinib after EGFR-TKI resistance was associated with longer PFS (P=0.019), whereas dramatic progression (P=0.014) had a detrimental effect on follow-up treatment. Grade 2 adverse events (AEs) were reported in four patients (17.39%) in the anlotinib monotherapy group and eight patients (32.00%) in the combination group. Of these, the most common grade 2 AEs were hypertension, fatigue, diarrhea, paronychia, mucositis and transaminase elevation. There were no grade 3/4/5 AEs. In conclusion, the present study demonstrated that low-dose anlotinib combined with EGFR-TKI is superior to anlotinib alone following EGFR-TKI failure, making it the preferred regimen for elderly patients with acquired EGFR-TKI resistance.

PRMT-1 and p120-Catenin as EMT Mediators in Osimertinib Resistance in NSCLC

Osimertinib, an irreversible tyrosine kinase inhibitor, is a first-line therapy in EGFR-mutant NSCLC patients. Prolonged treatment with Osimertinib leads to resistance due to an acquired C797S mutation in the EGFR domain and other mechanisms, such as epithelial-mesenchymal transition (EMT). In this study, we investigated the role of PRMT-1 and p120-catenin in mediating Osimertinib resistance (OR) through EMT. These studies found upregulation of gene and protein expression of PRMT-1, p120-catenin and Kaiso factor. Knockdown of p120-catenin using siRNA increased OR efficacy by 45% as compared to cells treated with mock siRNA and OR. After 24 h of transfection, the percentage wound closure in cells transfected with p120-catenin siRNA was 26.2%. However, in mock siRNA-treated cells the wound closure was 7.4%, showing its involvement in EMT. We also found high levels of p120-catenin expressed in 30% of smokers as compared to 5.5% and 0% of non-smokers and quit-smokers (respectively) suggesting that smoking may influence p120-catenin expression in NSCLC patients. These results suggest that biomarkers such as PRMT-1 may mediate EMT by methylating Twist-1 and increasing p120-catenin expression, which causes transcriptional activation of genes associated with Kaiso factor to promote EMT in Osimertinib-resistant cells.

Survival Analysis of 159 Patients With Advanced Non-Small-Cell Lung Cancer Resistant to First-Generation Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitor

Background

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) have limited or no response in some certain patients of non-small-cell lung cancer (NSCLC). However, real-world survival analyses comparing clinical data and EGFR-plasma mutation are still lacking.

Methods

In total, 159 patients with advanced NSCLC resistant to first-generation EGFR-TKIs were included for consecutive blood sampling in this study. Super-amplification refractory mutation system (Super-ARMS) was used to detect EGFR-plasma mutations and correlations between survival and circulating tumor DNA (ctDNA) were analyzed.

Results

Among 159 eligible patients, the T790M mutation was detected in 27.0% (43/159) of patients. The median progression-free survival (mPFS) was 10.7 months in all patients. Survival analysis revealed that patients with the T790M mutation had shorter progression-free survival (PFS) than those with the T790M wild-type (10.6 months vs 10.8 months, P = .038). Patients who cleared EGFR-plasma mutation had prolonged PFS compared with those with nonclearing EGFR-plasma mutation (11.6 months vs 9.0 months, P = .001). Cox multivariate analysis showed that the nonclearance of EGFR-plasma mutations was an independent risk factor for PFS (RR = 1.745, 95% CI: [1.184, 2.571], P = .005). The T790M mutation was associated with nonclearance of the EGFR-plasma mutation (χ2 = 10.407, P = .001).

Conclusion

Patients with advanced NSCLC who were resistant to the first-generation EGFR-TKI had a prolonged PFS with clearance of EGFR-plasma mutation. Those nonclearers were more likely to harbor T790M mutations in plasma.

Efficacy and Tolerability of Ramucirumab Plus Erlotinib in Taiwanese Patients with Untreated, Epidermal Growth Factor Receptor-Mutated, Stage IV Non-small Cell Lung Cancer in the RELAY Study

BACKGROUND

In RELAY, a randomized, double-blind, phase III trial investigating the efficacy and safety of ramucirumab+erlotinib (RAM+ERL) or ERL+placebo (PBO) in patients with untreated, stage IV, epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC), RAM+ERL demonstrated superior progression-free survival (PFS) versus PBO+ERL, with no new safety signals.

OBJECTIVE

The aim of this paper was to report efficacy and tolerability findings for the Taiwanese participants of RELAY.

PATIENTS AND METHODS

Patients were randomized 1:1 to RAM+ERL or ERL+PBO. Primary endpoint was investigator-assessed PFS. Secondary endpoints included objective response rate (ORR), duration of response (DoR) and tolerability. Data for the current analysis are reported descriptively.

RESULTS

In RELAY, 56 Taiwanese patients were enrolled; 26 received RAM+ERL, 30 received ERL+PBO. The demographic profile of the Taiwanese subgroup was consistent with that of the overall RELAY population. Median PFS for RAM+ERL/ERL+PBO, respectively, was 22.05 months/13.40 months (unstratified hazard ratio 0.4; 95% confidence interval 0.2-0.9); ORR was 92%/60%; median DoR was 18.2 months/12.7 months. All patients experienced one or more treatment-emergent adverse events (TEAEs); those most commonly reported were diarrhea and dermatitis acneiform (58% each) for RAM+ERL and diarrhea (70%) and paronychia (63%) for PBO+ERL. Grade ≥  3 TEAEs were experienced by 62%/30% of RAM+ERL/PBO+ERL patients, respectively, and included dermatitis acneiform (19%/7%), hypertension (12%/7%), and pneumonia (12%/0%).

CONCLUSIONS

PFS for the Taiwanese participants of RELAY receiving RAM+ERL versus ERL+PBO was consistent with that in the overall RELAY population. These results, together with no new safety signals and a manageable safety profile, may support first-line use of RAM+ERL in Taiwanese patients with untreated EGFR-mutant stage IV NSCLC.

TRIAL REGISTRATION

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Tumor Microenvironmental Cytokines Drive NSCLC Cell Aggressiveness and Drug-Resistance via YAP-Mediated Autophagy

Dynamic reciprocity between cellular components of the tumor microenvironment and tumor cells occurs primarily through the interaction of soluble signals, i.e., cytokines produced by stromal cells to support cancer initiation and progression by regulating cell survival, differentiation and immune cell functionality, as well as cell migration and death. In the present study, we focused on the analysis of the functional response of non-small cell lung cancer cell lines elicited by the treatment with some crucial stromal factors which, at least in part, mimic the stimulus exerted in vivo on tumor cells by microenvironmental components. Our molecular and functional results highlight the role played by the autophagic machinery in the cellular response in terms of the invasive capacity, stemness and drug resistance of two non-small lung cancer cell lines treated with stromal cytokines, also highlighting the emerging role of the YAP pathway in the mutual and dynamic crosstalk between tumor cells and tumor microenvironment elements. The results of this study provide new insights into the YAP-mediated autophagic mechanism elicited by microenvironmental cytokines on non-small cell lung cancer cell lines and may suggest new potential strategies for future cancer therapeutic interventions.

Pharmacological impact of microRNAs in head and neck squamous cell carcinoma: Prevailing insights on molecular pathways, diagnosis, and nanomedicine treatment

Head and neck squamous cell carcinoma is a disease that most commonly produce tumours from the lining of the epithelial cells of the lips, larynx, nasopharynx, mouth, or oro-pharynx. It is one of the most deadly forms of cancer. About one to two percent of all neo-plasm-related deaths are attributed to head and neck squamous cell carcinoma, which is responsible for about six percent of all cancers. MicroRNAs play a critical role in cell proliferation, differentiation, tumorigenesis, stress response, triggering apoptosis, and other physiological process. MicroRNAs regulate gene expression and provide new diagnostic, prognostic, and therapeutic options for head and neck squamous cell carcinoma. In this work, the role of molecular signaling pathways related to head and neck squamous cell carcinoma is emphasized. We also provide an overview of MicroRNA downregulation and overexpression and its role as a diagnostic and prognostic marker in head and neck squamous cell carcinoma. In recent years, MicroRNA nano-based therapies for head and neck squamous cell carcinoma have been explored. In addition, nanotechnology-based alternatives have been discussed as a promising strategy in exploring therapeutic paradigms aimed at improving the efficacy of conventional cytotoxic chemotherapeutic agents against head and neck squamous cell carcinoma and attenuating their cytotoxicity. This article also provides information on ongoing and recently completed clinical trials for therapies based on nanotechnology.

Design, Synthesis and Cytotoxicity Screening of New Thiazole Derivatives as Potential Anticancer Agents through VEGFR-2 Inhibition

Z-configurated isomers are kinetically preferred molecules. Compounds with Z-configuration are contained in many natural products, biologically active compounds and as synthons for organic synthesis. Two series of new thiazole-based analogs were synthesized from appropriate starting materials hydrazinecarbothioamide derivatives (Z)-2a,b to be evaluated for their inhibitory activity towards VEGFR-2. The prepared thiazole compounds 3a-5b were screened for their cytotoxic potency against the MDA-MB-231 breast cancer cell line and their percentage inhibition against VEGFR-2. Compound 4d exhibited good VEGFR-2 inhibitory activity. A DNA flow cytometry analysis was conducted, and compound 4d demonstrated cell cycle arrest at the G1 and G2/M phases of the cell cycle profile and an apoptosis-inducing effect by increasing the percentage of pre-G1 phase. Compound 4d was further evaluated for its apoptosis-inducing effect by studying the effect on mitochondrial membrane potential (MMP) and p53 activation. It was found to boost the level of p53 and reduce the level of MMP compared with the untreated control cells.