Vorolanib, a novel tyrosine receptor kinase receptor inhibitor with potent preclinical anti-angiogenic and anti-tumor activity

CM082 suppresses hypoxia-induced retinal neovascularization in larval zebrafish

Retinal neovascularization is a common feature of several ocular neovascular diseases, which are the leading cause of blindness in the world. Current treatments are administered through invasive intravitreal injections, leading to poor patient compliance, serious ocular complications and heavy economic burdens. Thus, an alternative less or non-invasive therapeutic strategy is in demand. Here, a non-invasive oral tyrosine kinase inhibitor, CM082, was evaluated in a retinal neovascularization model induced by hypoxia in zebrafish larvae. We found that CM082 effectively suppressed retinal neovascularization, rescued cell loss in the retinal ganglion cell layer, and rescued the visual function deficiency. Our results elucidated that CM082 mediated its therapeutic efficacy primarily through the inhibition of Vegfr2 phosphorylation. The findings demonstrated that CM082 possessed strong antiangiogenic effects and may serve as a potential treatment for angiogenesis in ocular neovascular diseases.

Vorolanib, sunitinib, and axitinib: A comparative study of vascular endothelial growth factor receptor inhibitors and their anti-angiogenic effects

PURPOSE

Pathological angiogenesis and vascular instability are observed in diabetic retinopathy (DR), diabetic macular edema (DME), and wet age-related macular degeneration (wAMD). Many receptor tyrosine kinases (RTKs) including vascular endothelial growth factor receptors (VEGFRs) contribute to angiogenesis, whereas the RTK TIE2 is important for vascular stability. Pan-VEGFR tyrosine kinase inhibitors (TKIs) such as vorolanib, sunitinib, and axitinib are of therapeutic interest over current antibody treatments that target only one or two ligands. This study compared the anti-angiogenic potential of these TKIs.

METHODS

A kinase HotSpot™ assay was conducted to identify TKIs inhibiting RTKs associated with angiogenesis and vascular stability. Half-maximal inhibitory concentration (IC50) for VEGFRs and TIE2 was determined for each TKI. In vitro angiogenesis inhibition was investigated using a human umbilical vein endothelial cell sprouting assay, and in vivo angiogenesis was studied using the chorioallantoic membrane assay. Melanin binding was assessed using a melanin-binding assay. Computer modeling was conducted to understand the TIE2-axitinib complex as well as interactions between vorolanib and VEGFRs.

RESULTS

Vorolanib, sunitinib, and axitinib inhibited RTKs of interest in angiogenesis and exhibited pan-VEGFR inhibition. HotSpot™ assay and TIE2 IC50 values showed that only axitinib potently inhibited TIE2 (up to 89%). All three TKIs effectively inhibited angiogenesis in vitro. In vivo, TKIs were more effective at inhibiting VEGF-induced angiogenesis than the anti-VEGF antibody bevacizumab. Of the three TKIs, only sunitinib bound melanin. TKIs differ in their classification and binding to VEGFRs, which is important because type II inhibitors have greater selectivity than type I TKIs.

CONCLUSIONS

Vorolanib, sunitinib, and axitinib exhibited pan-VEGFR inhibition and inhibited RTKs associated with pathological angiogenesis. Of the three TKIs, only axitinib potently inhibited TIE2 which is an undesired trait as TIE2 is essential for vascular stability. The findings support the use of vorolanib for therapeutic inhibition of angiogenesis observed in DR, DME, and wAMD.

New thiazolidine-2,4-diones as potential anticancer agents and apoptotic inducers targeting VEGFR-2 kinase: Design, synthesis, in silico and in vitro studies

BACKGROUND

VEGFR-2 has emerged as a prominent positive regulator of cancer progression.

AIM

Discovery of new anticancer agents and apoptotic inducers targeting VEGFR-2.

METHODS

Design and synthesis of new thiazolidine-2,4-diones followed by extensive in vitro studies, including VEGFR-2 inhibition assay, MTT assay, apoptosis analysis, and cell migration assay. In silico investigations including docking, MD simulations, ADMET, toxicity, and DFT studies were performed.

RESULTS

Compound 15 showed the strongest VEGFR-2 inhibitory activity with an IC50 value of 0.066 μM. Additionally, most of the synthesized compounds showed anti-proliferative activity against HepG2 and MCF-7 cancer cell lines at the micromolar range with IC50 values ranging from 0.04 to 4.71 μM, relative to sorafenib (IC50 = 2.24 ± 0.06 and 3.17 ± 0.01 μM against HepG2 and MCF-7, respectively). Also, compound 15 showed selectivity indices of 1.36 and 2.08 against HepG2 and MCF-7, respectively. Furthermore, compound 15 showed a significant apoptotic effect and arrested the cell cycle of MCF-7 cells at the S phase. Moreover, compound 15 had a significant inhibitory effect on the ability of MCF-7 cells to heal from. Docking studies revealed that the synthesized thiazolidine-2,4-diones have a binding pattern approaching sorafenib. MD simulations indicated the stability of compound 15 in the active pocket of VEGFR-2 for 200 ns. ADMET and toxicity studies indicated an acceptable pharmacokinetic profile. DFT studies confirmed the ability of compound 15 to interact with VEGFR-2.

CONCLUSION

Compound 15 has promising anticancer activity targeting VEGFR-2 with significant activity as an apoptosis inducer.

Drug-like properties of tyrosine kinase inhibitors in ophthalmology: Formulation and topical availability

Tyrosine kinase inhibitors (TKIs) can inhibit edema and neovascularization, such as in age-related macular degeneration and diabetic retinopathy. However, their topical administration in ophthalmology is limited by their toxicity and poor aqueous solubility. There are multiple types of TKIs, and each TKI has an affinity to more than one type of receptor. Studies have shown that ocular toxicity can be addressed by selecting TKIs that have a high affinity for specific vascular endothelial growth factor receptors (VEGFRs) but a low affinity for epidermal growth factor receptors (EGFRs). Drugs permeate from the aqueous tear fluid into the eye via passive diffusion. Thus, a sustained high concentration of the dissolved drug in the aqueous tear fluid is essential for a successful delivery to posterior tissues such as the retina. Unfortunately, the aqueous solubility of the TKIs that have the most favorable VEGFR/EGFR affinity ratio, that is, axitinib and cabozantinib, is well below 1 µg/mL, making their topical delivery very challenging. This is a review of the drug-like properties of TKIs that are currently being evaluated or have been evaluated as ophthalmic drugs. These properties include their solubilization, cyclodextrin complexation, and ability to permeate from the aqueous tear fluid to the posterior eye segment.

Potential oral VEGFR2 inhibitors: Treatment of wet age-related macular degeneration

Wet age-related macular degeneration (w-AMD) is one of the leading causes of vision loss in industrialized countries. A large body of evidence suggests that inhibitors targeting VEGFR2 may be effective in the treatment of w-AMD. The identification of an oral VEGFR2 inhibitor for the treatment of w-AMD provides an opportunity for a route of administration other than intravitreal injection. While screening potent VEGFR2 inhibitors at the enzyme and cellular levels, ensuring the safety of the compounds was our primary strategy for screening optimal compounds. Finally, compound 16 was identified, exhibiting enhanced inhibition of VEGFR2 enzyme and proliferation of BaF3-TEL-VEGFR2 cells compared to Vorolanib. Compound 16 had a weak inhibitory effect on human Ether-a-go-go-related gene (hERG) channel currents, showing a cardiac safety profile similar to Vorolanib. Compound 16 showed no significant toxicity to human liver cell LX-2, indicating a liver safety profile similar to Vorolanib. The water solubility of compound 16 was found to be higher than that of Vorolanib when tested at pH = 7.4. In addition, compound 16 was found to inhibit VEGFR2 phosphorylation in human umbilical vein endothelial cells (HUVECs) in a dose-dependent manner by WB assay. Furthermore, the in vitro preliminary evaluation of the drug-like properties of compound 16 showed remarkable plasma stability and moderate liver microsomal stability. Based on in vivo pharmacokinetic studies in ICR mice, compound 16 exhibited acceptable oral bioavailability (F = 20.2 %). Overall, these findings provide evidence that compound 16 is a leading potential oral drug candidate for w-AMD.

Treatment of acral and mucosal melanoma: Current and emerging targeted therapies

Targeted therapies revolutionized the management of patients with advanced and metastatic cutaneous melanoma. However, despite recent advances in the understanding of the molecular drivers of melanoma and its treatment with targeted therapies, patients with rare and aggressive melanoma subtypes, including acral melanoma (AM) and mucosal melanomas (MM), show limited long-term clinical benefit from current targeted therapies. While patients with AM or MM and BRAF or KIT mutations may benefit from targeted therapies, the frequency of these mutations is relatively low, and there are no genotype-specific treatments for most patients with AM or MM who lack common driver mutations. The poor prognosis of AM and MM can also be attributed to the lack of understanding of their unique molecular landscapes and clinical characteristics, due to being under-represented in preclinical and clinical studies. We review current knowledge of the molecular landscapes of AM and MM, focusing on actionable therapeutic targets and pathways for molecular targeted therapies, to guide the development of more effective targeted therapies for these cancers. Current and emerging strategies for the treatment of these melanoma subtypes using targeted therapies are also summarized.

A review of emerging tyrosine kinase inhibitors as durable treatment of neovascular age-related macular degeneration

INTRODUCTION

Current treatment for age-related macular degeneration poses a large burden on patients and the inability of patients to adhere to this immense burden can lead to worse visual outcomes. Novel treatments have been proposed to extend treatment intervals and reduce visit burden.

AREAS COVERED

This review article summarizes phase I and phase II clinical trials of tyrosine kinase inhibitors as durable treatment options for patient with neovascular age-related macular degeneration.

EXPERT OPINION

Tyrosine kinase inhibitors have shown substantial promise in reducing treatment burden while maintaining visual acuity and anatomic outcomes with favorable safety profiles. Several platforms have shown positive outcomes in initial trials and are currently moving toward phase III clinical trials.

Tyrosine Kinase Inhibitors and their role in treating neovascular age-related macular degeneration and diabetic macular oedema

The advent of intravitreal anti-VEGF injections has revolutionised the treatment of both neovascular age-related macular degeneration (nAMD or wet AMD) and diabetic macular oedema (DMO). Despite their efficacy, anti-VEGF injections precipitate significant treatment burden for patients, caregivers and healthcare systems due to the high frequency of injections required to sustain treatment benefit. Therefore, there remains an unmet need for lower-burden therapies. Tyrosine kinase inhibitors (TKI) are a novel class of drugs that may have considerable potential in addressing this issue. This review will summarise and discuss the results of various pilot studies and clinical trials exploring the role of TKIs in treatment of nAMD and DMO, highlighting promising candidates and possible challenges in developments.

Dihydroartemisinin inhibits melanoma migration and metastasis by affecting angiogenesis

Tumor angiogenesis is critical for tumor metastasis by providing oxygen, nutrients, and metastatic pathways. As a potential anti-angiogenic agent, Dihydroartemisinin (DHA) can effectively inhibit tumor metastasis. However, the mechanism how it regulates angiogenesis to affect tumor metastasis has not been fully clarified. To investigate the mechanisms of how DHA regulates melanoma progression. In this study, bioinformatics methods were used to analyze the correlation between angiogenesis and melanoma metastasis. Then, B16F10, A375, HUVECs and mouse metastasis models were adapted to clarify the inhibition of DHA in melanoma. GESA analysis revealed melanoma metastasis significantly positive correlated with angiogenesis. Meanwhile, DHA significantly decreased melanoma nodules and lung wet weight in metastatic tumor mice, and inhibited the expression of the angiogenic marker CD31 in vitro and in vivo. Similarly, DHA inhibited the expression of the angiogenic signal molecule VEGFR2 in A375 and B16F10 cells, and significantly suppressed the formation of their tubular structures. DHA-treated supernatants significantly inhibited the tubule-forming ability as well as lateral and longitudinal migration ability of HUVECs compared with untreated melanoma cell supernatants. Screening yielded the angiogenic pathways HIF-1α/VEGF, PI3K/ATK/mTOR associated with melanoma metastasis, and DHA may inhibit tumor metastasis by inhibiting these angiogenic pathways in melanoma cells to inhibit tumor metastasis. Further non-targeted metabolomics analysis revealed that DHA-treated model mice produced differential metabolites that were also associated with angiogenic pathways. DHA inhibits melanoma invasion and metastasis by mediating angiogenesis. These results have important implications for the potential use of DHA in treatment of melanoma.

The role of bone marrow microenvironment (BMM) cells in acute myeloid leukemia (AML) progression: immune checkpoints, metabolic checkpoints, and signaling pathways

Acute myeloid leukemia (AML) comprises a multifarious and heterogeneous array of illnesses characterized by the anomalous proliferation of myeloid cells in the bone marrow microenvironment (BMM). The BMM plays a pivotal role in promoting AML progression, angiogenesis, and metastasis. The immune checkpoints (ICs) and metabolic processes are the key players in this process. In this review, we delineate the metabolic and immune checkpoint characteristics of the AML BMM, with a focus on the roles of BMM cells e.g. tumor-associated macrophages, natural killer cells, dendritic cells, metabolic profiles and related signaling pathways. We also discuss the signaling pathways stimulated in AML cells by BMM factors that lead to AML progression. We then delve into the roles of immune checkpoints in AML angiogenesis, metastasis, and cell proliferation, including co-stimulatory and inhibitory ICs. Lastly, we discuss the potential therapeutic approaches and future directions for AML treatment, emphasizing the potential of targeting metabolic and immune checkpoints in AML BMM as prognostic and therapeutic targets. In conclusion, the modulation of these processes through the use of directed drugs opens up new promising avenues in combating AML. Thereby, a comprehensive elucidation of the significance of these AML BMM cells' metabolic and immune checkpoints and signaling pathways on leukemic cells can be undertaken in the future investigations. Additionally, these checkpoints and cells should be considered plausible multi-targeted therapies for AML in combination with other conventional treatments in AML. Video Abstract.

Efficacy and safety of vorolanib plus everolimus in metastatic renal cell carcinoma: A three-arm, randomised, double-blind, multicentre phase III study (CONCEPT)

BACKGROUND

Vorolanib is a highly potent tyrosine kinase inhibitor (TKI) targeting vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor. This three-arm, randomised, registered study aimed to assess the combination of vorolanib and everolimus or vorolanib alone versus a control arm of everolimus as second-line treatment in patients with metastatic renal cell carcinoma (RCC).

PATIENTS AND METHODS

Patients with advanced or metastatic RCC who had received one prior VEGFR-TKI were randomised (1:1:1) to receive the combination of vorolanib and everolimus or either monotherapy. Patients with brain metastases were excluded. The primary end-point was progression-free survival (PFS) assessed by the independent review committee per Response Evaluation Criteria in Solid Tumours v1.1.

RESULTS

Between 10th March 2017 and 30th May 2019, 399 patients (133 in each group) were enrolled. By the cutoff date (30th April 2020), a significant improvement in PFS was detected in the combination group compared with the everolimus group (10.0 versus 6.4 months; hazard ratio, 0.70; P = 0.0171). PFS was similar between the vorolanib group and the everolimus group (median: 6.4 versus 6.4 months; hazard ratio, 0.94; P = 0.6856). A significantly higher objective response rate was observed in the combination group than in the everolimus group (24.8% versus 8.3%; P = 0.0003), whereas there was no significant difference between the vorolanib group and the everolimus group (10.5% versus 8.3%; P = 0.5278). The overall survival data were immature. A total of 96 (72.2%), 52 (39.1%) and 71 (53.4%) grade 3 or higher treatment-related adverse events occurred in the combination group, vorolanib group and everolimus group, respectively.

CONCLUSIONS

The addition of vorolanib to everolimus as 2nd-line treatment for patients with advanced or metastatic RCC who have experienced cancer progression after VEGFR-TKI therapy provided a better objective response rate and PFS than everolimus alone with a manageable safety profile.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03095040; Chinadrugtrials, CTR20160987.