Vascular Endothelial Growth Factor A Isoforms Research Articles

The Molecular Pharmacology and Therapeutics of Angiogenesis

Angiogenesis is the formation of new vasculature on top of the pre-existing ones, which is critical during the species’ lifespan. It is responsible for delivering oxygen and nutrients to metabolically active tissues, therefore playing an essentialrole in physiological conditions, such as wound healing and pathological circumstances, like malignancies. Althoughsharing similar characteristics, the blood vessels in pathological angiogenesis develop irregularly and disorganizedly.Therefore, the leakage of materials from blood vessels is familiar in abnormal angiogenesis, which may result inmuch higher interstitial pressure than internal pressure. Whether the angiogenesis is physiological or pathological,the proliferation of normal dormant endothelial cells is an essential requirement. Additionally, angiogenesis is alsoinitiated by vascular endothelial growth factor A (VEGF-A) interacting with the vascular endothelial growth factorreceptor 2 (VEGFR2) or the co-receptor neuropilin-1 (NRP-1). The Vegfa gene can be spliced in many ways, creatingnumerous VEGF-A isoforms, each with unique interactions with VEGFR2. Several drugs have been approved as thefirst- or second-line of angiogenesis, thereby preventing cancer progression. The widely used is monoclonal antibodies(bevacizumab) and receptor tyrosine kinase inhibitor (sorafenib and axitinib). However, they lack selectivity and, asa result, are less effective and have considerable adverse effects. As a natural drug, Paclitaxel has an anti-angiogeniceffect in addition to its chemotherapeutic effect. However, different doses of paclitaxel have different anti-angiogenicmechanisms and different effects on different species.

The Molecular Pharmacology and Therapeutics of Angiogenesis

Angiogenesis is the formation of new vasculature on top of the pre-existing ones, which is critical during the species’ lifespan. It is responsible for delivering oxygen and nutrients to metabolically active tissues, therefore playing an essentialrole in physiological conditions, such as wound healing and pathological circumstances, like malignancies. Althoughsharing similar characteristics, the blood vessels in pathological angiogenesis develop irregularly and disorganizedly.Therefore, the leakage of materials from blood vessels is familiar in abnormal angiogenesis, which may result inmuch higher interstitial pressure than internal pressure. Whether the angiogenesis is physiological or pathological,the proliferation of normal dormant endothelial cells is an essential requirement. Additionally, angiogenesis is alsoinitiated by vascular endothelial growth factor A (VEGF-A) interacting with the vascular endothelial growth factorreceptor 2 (VEGFR2) or the co-receptor neuropilin-1 (NRP-1). The Vegfa gene can be spliced in many ways, creatingnumerous VEGF-A isoforms, each with unique interactions with VEGFR2. Several drugs have been approved as thefirst- or second-line of angiogenesis, thereby preventing cancer progression. The widely used is monoclonal antibodies(bevacizumab) and receptor tyrosine kinase inhibitor (sorafenib and axitinib). However, they lack selectivity and, asa result, are less effective and have considerable adverse effects. As a natural drug, Paclitaxel has an anti-angiogeniceffect in addition to its chemotherapeutic effect. However, different doses of paclitaxel have different anti-angiogenicmechanisms and different effects on different species.

The Molecular Pharmacology and Therapeutics of Angiogenesis

Angiogenesis is the formation of new vasculature on top of the pre-existing ones, which is critical during the species’ lifespan. It is responsible for delivering oxygen and nutrients to metabolically active tissues, therefore playing an essentialrole in physiological conditions, such as wound healing and pathological circumstances, like malignancies. Althoughsharing similar characteristics, the blood vessels in pathological angiogenesis develop irregularly and disorganizedly.Therefore, the leakage of materials from blood vessels is familiar in abnormal angiogenesis, which may result inmuch higher interstitial pressure than internal pressure. Whether the angiogenesis is physiological or pathological,the proliferation of normal dormant endothelial cells is an essential requirement. Additionally, angiogenesis is alsoinitiated by vascular endothelial growth factor A (VEGF-A) interacting with the vascular endothelial growth factorreceptor 2 (VEGFR2) or the co-receptor neuropilin-1 (NRP-1). The Vegfa gene can be spliced in many ways, creatingnumerous VEGF-A isoforms, each with unique interactions with VEGFR2. Several drugs have been approved as thefirst- or second-line of angiogenesis, thereby preventing cancer progression. The widely used is monoclonal antibodies(bevacizumab) and receptor tyrosine kinase inhibitor (sorafenib and axitinib). However, they lack selectivity and, asa result, are less effective and have considerable adverse effects. As a natural drug, Paclitaxel has an anti-angiogeniceffect in addition to its chemotherapeutic effect. However, different doses of paclitaxel have different anti-angiogenicmechanisms and different effects on different species.

Expression of neurotransmitters, vasculogenesis markers and myosin heavy chain isoforms in the masseter muscle of senescence-accelerated mouse prone 8 mice.

Learning and memory deficits and pathologic changes in the hippocampus caused by toothlessness and soft diet feeding are related to reduced masseter muscle (MM) function. Myosin heavy chain (MyHC) isoform expression in the MM also changes under different chewing conditions. The neurotransmitter calcitonin gene-related peptide (CGRP) and vascular endothelial growth factor A (VEGF-A) are involved in MM formation. However, the relationship between CGRP, VEGF-A and MyHC isoforms in the MM in the senescence-accelerated mouse prone 8 (SAMP8) strain, a model of learning and memory deficits, remains unclear. Changes in CGRP, VEGF-A, vasculogenesis marker, and MyHC isoform mRNA expression in the MMs of aging SAMP8 and senescence-accelerated mouse resistant 1 (SAMR1) mice was investigated through quantitative real-time polymerase chain reaction (qRT-PCR) and in situ hybridization. qRT-PCR revealed obviously high CGRP levels in the SAMP8 mouse MM (p<0.001). MyHC-IId/x mRNA expression in the MM was higher in 24-week-old SAMP8 mice than 24-week-old SAMR1 mice (p<0.001) but lower in slow-MyHC SAMP8 mice than SAMR1 mice (p<0.001). CGRP mRNA was observed on the muscle fibers of the SAMP8 mouse MM but not the SAMR1 mouse MM through in situ hybridization. Principal component analysis (PCA) revealed strong positive contributions of SAMP8-MyHC-IId/x, SAMP8-CGRP, SAMR1-MyHC-emb, SAMR1-CGRP, SAMR1-VEGF-A, SAMR1-CD31, SAMP8-VEGF-A, and SAMP8-CD31 in the MM at 12 and 24 weeks. CGRP is also key for the MyHC-IId/x and slow-MyHC patterns in the MMs of SAMP8 mice.

VEGF-A165 is the predominant VEGF-A isoform in platelets, while VEGF-A121 is abundant in serum and plasma from healthy individuals.

Vascular endothelial growth factor A (VEGF-A) plays pivotal roles in regulating tumor angiogenesis as well as physiological vascular function. The major VEGF-A isoforms, VEGF-A121 and VEGF-A165, in serum, plasma, and platelets have not been exactly evaluated due to the lack of the appropriate assay system. Antibodies against human VEGF-A121 and VEGF-A165 (hVEGF-A121 and hVEGF-A165) were successfully produced and Enzyme-Linked ImmunoSorbent Assay (ELISA) for hVEGF-A121 and hVEGF-A165 were separately created by these monoclonal antibodies. The measurement of recombinant hVEGF-A121 and hVEGF-A165 by the created ELISA showed no cross-reaction between hVEGF-A121 and hVEGF-A165 in conditioned media from HEK293 cells transfected with either hVEGF-A121 or hVEGF-A165 expression vector. The levels of VEGF-A121 and VEGF-A165 in serum, plasma, and platelets from 59 healthy volunteers proved that VEGF-A121 level was higher than VEGF-A165 in both plasma and serum in all the cases. VEGF-A121 or VEGF-A165 in serum represented higher level than that in plasma. In contrast, the level of VEGF-A165 was higher than VEGF-A121 in platelets. The newly developed ELISAs for hVEGF-A121 and hVEGF-A165 revealed different ratios of VEGF isoforms in serum, plasma, and platelets. Measuring these isoforms in combination provides useful information as biomarkers for diseases involving VEGF-A121 and VEGF-A165.

NGF Prevents Loss of TrkA/VEGFR2 Cells, and VEGF Isoform Dysregulation in the Retina of Adult Diabetic Rats.

Among the factors involved in diabetic retinopathy (DR), nerve growth factor (NGF) and vascular endothelial growth factor A (VEGFA) have been shown to affect both neuronal survival and vascular function, suggesting that their crosstalk might influence DR outcomes. To address this question, the administration of eye drops containing NGF (ed-NGF) to adult Sprague Dawley rats receiving streptozotocin (STZ) intraperitoneal injection was used as an experimental paradigm to investigate NGF modulation of VEGFA and its receptor VEGFR2 expression. We show that ed-NGF treatment prevents the histological and vascular alterations in STZ retina, VEGFR2 expression decreased in GCL and INL, and preserved the co-expression of VEGFR2 and NGF-tropomyosin-related kinase A (TrkA) receptor in retinal ganglion cells (RGCs). The WB analysis confirmed the NGF effect on VEGFR2 expression and activation, and showed a recovery of VEGF isoform dysregulation by suppressing STZ-induced VEGFA121 expression. Reduction in inflammatory and pro-apoptotic intracellular signals were also found in STZ+NGF retina. These findings suggest that ed-NGF administration might favor neuroretina protection, and in turn counteract the vascular impairment by regulating VEGFR2 and/or VEGFA isoform expression during the early stages of the disease. The possibility that an increase in the NGF availability might contribute to the switch from the proangiogenic/apoptotic to the neuroprotective action of VEGF is discussed.

Hypophysial angiogenesis decodes annual time and underlies physiological adaptation to seasonal changes in the environment.

Adaptation to annual changes in the environment is controlled by hypophysial hormones. In temperate zones, photoperiod is the primary external cue that regulates annual biological cycles and is translated by the pattern of melatonin secretion acting primarily in the hypophysial pars tuberalis. Angiogenic mechanisms within this tissue contribute to decode the melatonin signal through alternative splicing of the vascular endothelial growth factor A (VEGF-A) gene in both the pars tuberalis and the capillary loops of the infundibulum. The resulting melatonin-evoked differential productions of VEGF-A isoforms will induce seasonal remodeling of the vascular connection between the hypothalamus and hypophysis, and act as paracrine messengers in the pars distalis to generate the required seasonal endocrine response. Specifically, the long melatonin signal in winter upregulates antiangiogenic VEGF-A isoforms, which will reduce the number of vascular loops and the density of VEGF receptors in endocrine and folliculo-stellate (FS) cells, inhibit prolactin secretion, and stimulate FSH. In contrast, the short melatonin signal in summer upregulates proangiogenic VEGF-A isoforms that will increase the number of vascular loops and the density of VEGF receptors in endocrine and FS cells, stimulate prolactin secretion, and suppress FSH. A similar system has been identified in long day seasonal breeders, revealing that this is a conserved mechanism of adaptation across species. Thus, an angiogenesis-based, intrahypophysial system for annual time measurement controls local microvascular plasticity and conveys the photoperiodic signal readout from the melatonin sensitive pars tuberalis to the endocrine cells of the pars distalis to regulate seasonal adaptation to the environment.

MALAT1-dependent hsa_circ_0076611 regulates translation rate in triple-negative breast cancer

Vascular Endothelial Growth Factor A (VEGFA) is the most commonly expressed angiogenic growth factor in solid tumors and is generated as multiple isoforms through alternative mRNA splicing. Here, we show that lncRNA MALAT1 (metastasis-associated lung adenocarcinoma transcript 1) and ID4 (inhibitor of DNA-binding 4) protein, previously referred to as regulators of linear isoforms of VEGFA, induce back-splicing of VEGFA exon 7, producing circular RNA circ_0076611. Circ_0076611 is detectable in triple-negative breast cancer (TNBC) cells and tissues, in exosomes released from TNBC cells and in the serum of breast cancer patients. Circ_0076611 interacts with a variety of proliferation-related transcripts, included MYC and VEGFA mRNAs, and increases cell proliferation and migration of TNBC cells. Mechanistically, circ_0076611 favors the expression of its target mRNAs by facilitating their interaction with components of the translation initiation machinery. These results add further complexity to the multiple VEGFA isoforms expressed in cancer cells and highlight the relevance of post-transcriptional regulation of VEGFA expression in TNBC cells.

Future Perspectives for Antiangiogenic Therapy in Retinal Diseases

The World Health Organization considers eye disorders as the serious problem of our time [1]. According to world statistics, the number of people with visual impairment is 1.3 billion, most of this number are people over 50 years old [2]. Over the past 20 years, developments in the treatment of AMD and fundus diseases have advanced and include drugs such as vascular endothelial growth factor inhibitors. The molecular structures of drugs intended for intravitreal use range from RNA aptamers (pegaptanib) to full-length monoclonal antibodies (mAb: bevacizumab) to Fab fragments (ranibizumab) and an antibody conjugate (aflibercept). In addition, single-chain variable fragment (scFv: brolucizumab), bispecific monoclonal antibody (faricimab) and DARPin (abigar pegol) show promising results in clinical trials.[6],[7] Brolucizumab (RTH258) was developed by ESBATech (ES-BATech AG — Schlieren ZH, Switzerland) originally under the name ESBA1008, an inhibitor of the humanized single chain antibody fragment (scFv) of all isoforms of vascular endothelial growth factor-A (VEGF-A). [6],[7],[11]. The Faricimab (ROCHE, Switzerland) molecule is characterized by the presence of a bispecific antibody that simultaneously binds to both VEGF-A and Ang-2; the drug consists of an anti-Ang-2 antigen-binding fragment (Fab), an anti-VEGF-A Fab and a crystallizing modified fragment (Fc region) with a total size of 150 kDa. This “crossover” effect provided high affinity for both targets while also maintaining a good stability profile compared to natural antibodies [8]. Abicipar Pegol (Abicipar, Allergan. Dublin, Ireland) is a DARPin aimed at binding all VEGF-A isoforms, like ranibizumab. It has a higher affinity and a longer half-life from the eye than ranibizumab (&gt;13 days versus 7.2 days), making it a potential drug with a longer duration of action and the need for less frequent injections [15]. In this article, we tried to summarize the literature data on new anti-VEGF drugs being developed and ready for release. We hope that the appearance of these drugs on the market will make it possible to reduce the injection load on the patient and optimize their material costs.

CircSMARCA5-SRSF1 interaction is functionally involved in GBM pathogenesis

Glioblastoma multiforme (GBM) is the most aggressive human brain tumor with a median survival of 15 months. The standard treatments of GBM and the total medical resection are unable to contrast this mortal cancer. For these reason new diagnostic approaches and therapies are needed. The identification of molecular features of this cancer may allow to create a personalized therapy. Circular RNAs (circRNAs) are a new class of non-coding RNAs (ncRNAs) highly enriched in brain, stable within the cells, detectable in body fluids and having a potential role and biological importance still object of debate. This thesis investigated the putative involvement of circRNAs in GBM pathogenesis. It has been demonstrated that circSMARCA5 is downregulated in GBM biopsies, its expression is associated to the glioma grade malignancy and it negatively regulates migration of U87MG cells. Moreover, it has been proved the physical interaction between circSMARCA5 and one of its predicted interactor Serine/arginine-rich splicing factor 1 (SRSF1). Interesting splicing targets of SRSF1 are the serine and arginine rich splicing factor 3 (SRSF3) and the vascular endothelial growth factor A (VEGFA). It has been proposed that circSMARCA5 may regulate the alternative splicing of SRSF3 in favor of the formation of a stable oncoprotein in GBM. It also regulates the alternative splicing of VEGFA mRNA through the binding to SRSF1. In addition, blood vascular microvessel density evaluated in GBM negatively correlates with the expression of circSMARCA5, while positively correlates with that of SRSF1 and pro-to-anti-angiogenic VEGFA isoform ratio. GBM patients with low circSMARCA5 expression have lower overall and progression free survival rates. Based on these findings, CircSMARCA5 could be considered a promising druggable tumor suppressor in GBM. Moreover, its interaction with SRSF1 makes circSMARCA5 an upstream regulator of pro- to anti-angiogenic VEGFA isoforms ratio within GBM cells and a highly promising GBM prospective anti-angiogenic molecule.

Endostatin and Vascular Endothelial Growth Factor-A165b May Contribute to Classification of Pulmonary Hypertension.

Background: Pulmonary hypertension (PH) is characterized by dysregulation of small pulmonary arteries. In addition to endostatin (ES), placenta growth factor (PlGF), vascular endothelial growth factor-A (VEGF-A), and the anti-angiogenesis isoform of VEGF-A (VEGF-A165b) are associated with PH. However, the usefulness of these biomarkers in PH in unknown. We investigated whether these 4 biomarkers are related to PH classification.Methods and Results: Between July 2015 and August 2017, 33 control patients and 107 PH patients were enrolled in the study. Among the PH patients, 48 had pulmonary arterial hypertension (PAH), 5 had left heart disease-associated PH (LHD-PH), 4 had lung disease-associated PH (LD-PH), and 50 had chronic thromboembolic PH (CTEPH). Among the PAH patients, 16 had idiopathic PAH (IPAH) and 17 had connective tissue disease-associated PAH (CTD-PAH). PlGF, total VEGF-A, and VEGF-A165b levels were measured in the control and PH groups. ES was only measured in the PH group. VEGF-A165b levels were significantly higher in the LD-PH group than in the PAH, LHD-PH, and CTEPH groups (all P<0.001). PlGF levels were significantly higher in the CTD-PAH group than in the IPAH and control groups. ES levels were significantly correlated with the 6-min walk distance (P<0.001), B-type natriuretic peptide (P<0.001), and pulmonary vascular resistance (P=0.008).Conclusions: ES could detect CTD-PAH in PAH and may be an indicator of PH severity. VEGF-A165b was useful in detecting LD-PH.

Overexpression of VEGF165 is associated with poor prognosis of cervical cancer

Cervical cancer is a major health hazard to Indian women. Human papillomavirus (HPV) infection is an established risk factor for cervical carcinogenesis. However, understanding the cervical cancer biology beyond HPV infection is very crucial to predict aggressive behavior, prognosis, treatment response and survival. In the present study, we explored the role of vascular endothelial growth factor A (VEGFA) isoforms, VEGFC and VEGFD in cervical cancer progression and its association with HPV 16 and 18 infections. A total of 110 cervical cancer tissues and 50 normal cervical tissues were collected for the study. Reverse transcription-polymerase chain reaction was employed to analyze tissue VEGFA isoforms, VEGFC and VEGFD expression. VEGF165 was significantly higher, whereas VEGFC and VEGFD were significantly lower in malignant cervical carcinoma tissues as compared to normal cervix tissues. Expression levels of VEGF121 and VEGFC were significantly associated with type of tumor growth while VEGF165 was significantly associated with lymph node metastasis. VEGF165 transcript levels were significantly higher in patients with squamous cell carcinoma (SCC) and developed recurrence. Most strikingly, higher VEGF165 expression was significantly associated with worst disease-free survival (DFS) specifically in patients with SCC. Association of VEGF165 with lymph node metastasis, disease recurrence and worst DFS indicated that VEGF165 is an important prognostic factor in cervical carcinogenesis.

The Regulatory Effect of VEGF-Ax on Rat Bone Marrow Mesenchymal Stem Cells' Angioblastic Differentiation and Its Proangiogenic Ability.

Vascular endothelial growth factor A (VEGFA), which plays a key role in angiogenesis, is composed of many isoforms. Distinct VEGFA isoforms are generated by alternative splicing of VEGFA mRNA and named as VEGFxxx, where xxx represents the number of amino acids present in the final protein sequence. These isoforms have opponent pro- and antiangiogenic effects. VEGF-Ax, an additional isoform containing a 22-amino-acid extension in the COOH terminus, arising from VEGFA mRNA, programmed translational readthrough. The function of VEGF-Ax is not clear, especially the conclusion that VEGF-Ax regulates angiogenesis is contradictory. Thus, we investigated the effect of VEGF-Ax on differentiation and angiogenesis of rat bone marrow mesenchymal stem cells (BMMSCs). The results showed that VEGF-Ax could promote the proliferation and migration of BMMSCs, stimulate the differentiation of BMMSCs into endothelial cell-like cells, and protect BMMSCs from endoplasmic reticulum stress-induced apoptosis.

Vascular Endothelial Growth Factor A and VEGFR-1 Change during Preimplantation in Heifers.

Vascular endothelial growth factor A (VEGFA) plays a critical angiogenic role in the endometrium of placentalia during preimplantation. The role of VEGFA and its receptors is not fully characterised in bovine reproduction. We analysed the mRNA expression of VEGFA isoforms 121, 165 and 189, and VEGF receptors 1 and 2 in three experimental settings (A, B and C). We compared intercaruncular endometrium of cyclic to pregnant heifers at Days 12, 15 and 18 post insemination (Day 0), and between Day 15 and Day 18 conceptuses (A). We further compared caruncular versus intercaruncular endometrium at Day 15 (B), and endometrium of heifers carrying embryos originating from somatic cell nuclear transfer (SCNT) versus in vitro fertilisation (IVF) at Day 18 (C). Endometrial VEGFA protein was localised and quantified. Pregnant heifers displayed lower intercaruncular endometrial mRNA expression of VEGFA-121 (p = 0.045) and VEGFA-189 (p = 0.009) as well as lower VEGFA protein abundance (p < 0.001) at Day 15. The VEGFA protein was localised in intercaruncular luminal, glandular epithelium and in tunica muscularis of blood vessels. At Day 15, caruncular endometrium displayed higher VEGFA mRNA expression than intercaruncular endometrium (p < 0.05). Intercaruncular endometrial VEGFA protein at Day 18 was higher in abundance in SCNT than in IVF (p = 0.038). Therefore, during preimplantation in cattle, there may be a need for timely physiological reduction in intercaruncular endometrial VEGFA expression in favour of the caruncular area to facilitate a gradient towards the implantation sites. A higher expression of VEGFA in SCNT may predispose for later placentation abnormalities frequently observed following SCNT.

Evaluation of recombinant human vascular endothelial growth factor VEGF121-loaded poly-l-lactide microparticles as a controlled release delivery system.

Vascular endothelial growth factor A (VEGF-A) is an important growth factor that plays a major role in angiogenesis. With different isoforms distributed in various tissues, the shortest isoform of VEGF-A is VEGF121, one of the physiologically functional variants next to VEGF165. It is well known that VEGF has a shorter half-life, and the stability of the protein must be considered in therapeutic aspects. Poly-l-lactide (PLA) microparticles can release the encapsulated protein in a sustained release mode. In this study, the VEGF121 gene was cloned and expressed in a prokaryotic expression system (Escherichia coli). The recombinant VEGF121 was encapsulated with PLA microparticles and studied in vitro and ex ovo for the sustained release mechanism. The PLA-VEGF microparticles and the recombinant VEGF121 were explored for their bioactivity in human umbilical vein endothelial cells (HUVEC). VEGF released in vitro from PLA microparticles on days 1, 20, and 30 showed remarkable biological activity compared to PBS-loaded PLA microparticles such as the ability of the cells to proliferate, migrate, and form tubes similar to recombinant VEGF121. Besides, PLA-VEGF microparticles and the recombinant VEGF121 were also tested for their proangiogenic action in embryonated eggs by chicken chorioallantoic membrane assay (CAM), and the effect was observed in both forms. This study suggests that PLA-loaded VEGF microparticles in a sustainable release format can be effectively used in proangiogenic therapy and reduce the adverse effects caused due to multiple dosages.

Vascular endothelial growth factor A isoforms modulate follicle development in peripubertal heifers independent of diet through diverse signal transduction pathways.

Follicular progression during peripuberty is affected by diet. Vascular endothelial growth factor A (VEGFA) induces follicle progression in many species; however, there are limited studies to determine if diet may alter the effects of angiogenic VEGFA165-stimulated follicle progression or antiangiogenic VEGFA165b follicle arrest. We hypothesized that diet affects the magnitude of angiogenic and antiangiogenic VEGFA isoform actions on follicular development through diverse signal transduction pathways. To test this hypothesis, beef heifers in our first trial received Stair-Step (restricted and refeeding) or control diets from 8 to 13months of age. Ovaries were collected to determine follicle stages, measure vascular gene expression and conduct ovarian cortical cultures. Ovarian cortical cultures were treated with phosphate-buffered saline (control), 50ng/ml VEGFA165, VEGFA165b, or VEGFA165+VEGFA165b. The Stair-Step heifers had more primordial follicles (P<0.0001), greater messenger RNA abundance of vascular markers VE-cadherin (P<0.0001) and NRP-1 (P<0.0051) than controls at 13months of age prior to culture. After culture, VEGFA isoforms had similar effects, independent of diet, where VEGFA165 stimulated and VEGFA165b inhibited VEGFA165-stimulated follicle progression from early primary to antral follicle stages. In vitro cultures were treated with VEGFA isoforms and signal transduction array plates were evaluated. VEGFA165 stimulated expression of genes related to cell cycle, cell proliferation, and growth while VEGFA165b inhibited expression of those genes. Thus, VEGFA isoforms can act independently of diet to alter follicle progression or arrest. Furthermore, follicle progression can be stimulated by VEGFA165 and inhibited by VEGFA165b through diverse signal transduction pathways.

Correlation of axial length and myopic macular degeneration to levels of molecular factors in the aqueous

To elucidate the molecular processes associated with the development of myopic macular degeneration (MMD), we measured the intraocular concentrations of molecular factors in emmetropic and myopic eyes. This is a retrospective clinic-based case-control study that included eyes undergoing routine cataract surgery whereby aqueous humour samples were obtained. We measured the concentrations of pigment epithelium derived factor(PEDF), matrix metalloproteinase 2(MMP-2), tissue inhibitor of metalloproteinase(TIMP-2), vascular endothelial growth factor isoform A(VEGF-A), interleukin 8(IL-8), interleukin 6(IL-6), C-reactive protein(CRP), angiopoietin 2(Ang2), and amphiregulin. 38 eyes (axial length (AL): 22.4–32.4 mm), including 12 highly myopic (HM) eyes (AL ≥ 26.5 mm) without MMD and 12 HM eyes with MMD but without neovascularization were included. Eyes with MMD were found to have significantly lower VEGF-A levels (p = 0.007) and higher MMP-2 levels (p = 0.02) than control eyes after adjusting for age and gender. MMP-2 levels correlated positively (r = 0.58, p = 0.002), while VEGF-A levels correlated negatively with longer axial length (r = −0.75, p < 0.001). Both the concentrations of VEGF-A (P = 0.25) and MMP-2 (P = 0.69) were not significantly associated with MMD after adjusting for AL. These findings suggest that the predominant mechanism underlying the development of non-neovascular MMD may be axial elongation, driven in part by MMP-2 related mechanisms.

Angiogenic and Antiangiogenic VEGFA Splice Variants in Colorectal Cancer: Prospective Retrospective Cohort Study in Patients Treated With Irinotecan-Based Chemotherapy and Bevacizumab

BackgroundAlternative splicing of vascular endothelial growth factor A (VEGFA) results in VEGFAxxxb antiangiogenic isoforms that fail to activate angiogenesis. Bevacizumab, widely used in patients with metastatic colorectal cancer (CRC), binds both VEGFA and VEGFAxxxb isoforms. Patients and MethodsFormalin-fixed, paraffin-embedded primary tumors from metastatic CRC patients treated with first-line FOLFIRI (leucovorin, 5-fluorouracil, irinotecan, and oxaliplatin) + bevacizumab (n = 285) or FOLFIRI only (n = 75) were collected. The relative expression of VEGFA121a, 121b, 145a, 145b, 165a, and 165b was assessed with custom TaqMan-MGB assays and quantitative PCR. ResultsAt a median follow-up of 101.5 months, left-sided primary CRC was a favorable prognosticator (median survival, 29.2 vs. 18.2 months; P = .015). Positive high VEGFA145b was an unfavorable factor for progression-free survival (PFS; hazard ratio [HR] = 1.66; 95% confidence interval [CI], 1.13-2.44; P = .009) in patients who received FOLFIRI + bevacizumab, without prognostic significance in FOLFIRI-only patients (HR = 0.70; 95% CI, 0.34-1.44; P = .33). The adverse effect on PFS of 145b was more pronounced in patients with right-sided colon cancer (HR = 2.62; 95% CI, 1.35-5.12; P = .005), especially in those who received bevacizumab (HR = 2.85; 95% CI, 1.31-6.21; P = .008). In patients with right-sided colon primary tumors, isoform 121b correlated with inferior PFS (HR = 1.73; 95% CI, 0.94-3.18; P = .076) and overall survival (OS; HR = 2.0; 95% CI, 1.08-3.72; P = .028). In patients with left-sided primary tumors, positive high 165b correlated with superior PFS (HR = 0.76; 95% CI, 0.59-0.99; P = .044) and OS (HR = 0.68; 95% CI, 0.52-0.90; P = .006). At multivariate analysis, right-sided primary tumor was associated with inferior PFS (HR = 1.28; 95% CI, 1.00-1.64), while 145b consistently retained predictive significance for lack of benefit in PFS with bevacizumab (HR = 1.71; 95% CI, 1.16-2.53). Multivariate analysis for OS showed that VEGFA165b expression was favorable in patients with left-sided but unfavorable in patients with right-sided primary tumors (Pinteraction < .001). ConclusionThe antiangiogenic isoform VEGFA145b messenger RNA may predict resistance to bevacizumab. Differences in biological relevance and prognostic significance of various VEGFA isoforms were found for right- versus left-sided primary tumors.

Targeting Angiogenesis in Prostate Cancer.

Prostate cancer is the most commonly diagnosed cancer among men in the Western world. Although localized disease can be effectively treated with established surgical and radiopharmaceutical treatments options, the prognosis of castration-resistant advanced prostate cancer is still disappointing. The objective of this study was to review the role of angiogenesis in prostate cancer and to investigate the effectiveness of anti-angiogenic therapies. A literature search of clinical trials testing the efficacy of anti-angiogenic therapy in prostate cancer was performed using Pubmed. Surrogate markers of angiogenic activity (microvessel density and vascular endothelial growth factor A (VEGF-A) expression) were found to be associated with tumor grade, metastasis, and prognosis. Six randomizedstudies were included in this review: two phase II trials on localized and hormone-sensitive disease (n = 60 and 99 patients) and four phase III trials on castration-resistant refractory disease (n = 873 to 1224 patients). Although the phase II trials showed improved relapse-free survival and stabilisation of the disease, the phase III trials found increased toxicity and no significant improvement in overall survival. Although angiogenesis appears to have an important role in prostate cancer, the results of anti-angiogenic therapy in castration-resistant refractory disease have hitherto been disappointing. There are various possible explanations for this lack of efficacy in castration-resistant refractory disease: redundancy of angiogenic pathways, molecular heterogeneity of the disease, loss of tumor suppressor protein phosphatase and tensin homolog (PTEN) expression as well as various VEGF-A splicing isoforms with pro- and anti-angiogenic activity. A better understanding of the molecular mechanisms of angiogenesis may help to develop effective anti-angiogenic therapy in prostate cancer.

CircSMARCA5 Regulates VEGFA mRNA Splicing and Angiogenesis in Glioblastoma Multiforme Through the Binding of SRSF1.

Circular RNAs are a large group of RNAs whose cellular functions are still being investigated. We recently proposed that circSMARCA5 acts as sponge for the splicing factor Serine and Arginine Rich Splicing Factor 1 (SRSF1) in glioblastoma multiforme (GBM). After demonstrating by RNA immunoprecipitation a physical interaction between SRFS1 and circSMARCA5, we assayed by real-time PCR in a cohort of 31 GBM biopsies and 20 unaffected brain parenchyma controls (UC) the expression of total, pro-angiogenic (Iso8a) and anti-angiogenic (Iso8b) mRNA isoforms of Vascular Endothelial Growth Factor A (VEGFA), a known splicing target of SRSF1. The Iso8a to Iso8b ratio: (i) increased in GBM biopsies with respect to UC (p-value < 0.00001); (ii) negatively correlated with the expression of circSMARCA5 (r-value = −0.46, p-value = 0.006); (iii) decreased in U87-MG overexpressing circSMARCA5 with respect to negative control (p-value = 0.0055). Blood vascular microvessel density, estimated within the same biopsies, negatively correlated with the expression of circSMARCA5 (r-value = −0.59, p-value = 0.00001), while positively correlated with that of SRSF1 (r-value = 0.38, p-value = 0.00663) and the Iso8a to Iso8b ratio (r-value = 0.41, p-value = 0.0259). Kaplan-Meier survival analysis showed that GBM patients with low circSMARCA5 expression had lower overall and progression free survival rates than those with higher circSMARCA5 expression (p-values = 0.033, 0.012, respectively). Our data convincingly suggest that circSMARCA5 is an upstream regulator of pro- to anti-angiogenic VEGFA isoforms ratio within GBM cells and a highly promising GBM prognostic and prospective anti-angiogenic molecule.