The retinoid X receptor-selective ligand, LGD1069, inhibits tumor-induced angiogenesis via suppression of VEGF in human non-small cell lung cancer

Causal effects of retinol and vitamin D on tongue cancer risk: a mendelian randomization study

BACKGROUND

Previous studies have indicated that retinol and vitamin D may be associated with the oncogenesis of tongue cancer. Therefore, we aimed to assess the causal relationships of retinol and vitamin D with the risk of tongue cancer using the two-sample Mendelian randomization (MR) method.

METHODS

Single nucleotide polymorphisms (SNPs) related to retinol, vitamin D and tongue cancer were obtained from the up-to-date genome-wide association study (GWAS) catalogue, which was screened for instrumental variables (IVs). We performed two-sample MR analyses and used inverse-variance weighted (IVW) as the primary method. Additionally, we used the MR-pleiotropy residual sum and outlier (MR-PRESSO) method, MR-Egger intercept analysis, Cochran's Q test and leave-one-out analysis to evaluate the sensitivity of MR.

RESULTS

The IVW method revealed that retinol was not significantly correlated with the risk of tongue cancer (OR = 0.8602; 95% CI = 0.4453-1.6617; P = 0.654). However, the causal relationship between vitamin D and the risk of tongue cancer was significant according to IVW (OR = 0.4003; 95% CI = 0.1868-0.8577; P = 0.019). The sensitivity analysis did not detect any significant horizontal pleiotropy or heterogeneity.

CONCLUSIONS

Given the limitations of this study, our MR study suggests that retinol is unlikely to influence the risk of tongue cancer, but vitamin D may decrease the risk of tongue cancer.

Targeting Nuclear Receptors in Lung Cancer—Novel Therapeutic Prospects

Lung cancer, the second most commonly diagnosed cancer, is the major cause of fatalities worldwide for both men and women, with an estimated 2.2 million new incidences and 1.8 million deaths, according to GLOBOCAN 2020. Although various risk factors for lung cancer pathogenesis have been reported, controlling smoking alone has a significant value as a preventive measure. In spite of decades of extensive research, mechanistic cues and targets need to be profoundly explored to develop potential diagnostics, treatments, and reliable therapies for this disease. Nuclear receptors (NRs) function as transcription factors that control diverse biological processes such as cell growth, differentiation, development, and metabolism. The aberrant expression of NRs has been involved in a variety of disorders, including cancer. Deregulation of distinct NRs in lung cancer has been associated with numerous events, including mutations, epigenetic modifications, and different signaling cascades. Substantial efforts have been made to develop several small molecules as agonists or antagonists directed to target specific NRs for inhibiting tumor cell growth, migration, and invasion and inducing apoptosis in lung cancer, which makes NRs promising candidates for reliable lung cancer therapeutics. The current work focuses on the importance of various NRs in the development and progression of lung cancer and highlights the different small molecules (e.g., agonist or antagonist) that influence NR expression, with the goal of establishing them as viable therapeutics to combat lung cancer.

REC8 suppresses tumor angiogenesis by inhibition of NF-κB-mediated vascular endothelial growth factor expression in gastric cancer cells

Background

Tumor angiogenesis is an essential event for tumor growth and metastasis. It has been showed that REC8, a component of the meiotic cohesion complex, played a vital role in Epithelial-Mesenchymal Transition (EMT) in gastric cancer. However, the role of REC8 in gastric cancer angiogenesis remains to be identified.

Results

Inhibition of REC8 expression in gastric cancer cells contributed to tumor angiogenesis in the gastric cancer microenvironment. The clinical analysis demonstrated that the loss of REC8 in gastric cancer with enrichment of MVD. Depletion of REC8 expression in gastric cancer cells significantly increased tube formation of human umbilical vein endothelial cells (HUVECs), which is attributed to enhancement of vascular endothelial growth factor (VEGF) secretion caused by REC8 slicing. While addition of neutralizing antibody targeted VEGF into supernatant drastically reversed the effect of REC8 loss in gastric cancer cells on tube formation. Mechanistic analyses indicated that ablation of REC8 promotes nuclear factor-κB (NF-κB) p65 activity and its downstream gene VEGF expression, leading to tube formation.

Conclusions

These results demonstrated a novel REC8 function that suppressed tumor angiogenesis and progression by attenuation of VEGF in gastric cancer microenvironment.

Electronic supplementary material

The online version of this article (10.1186/s40659-020-00307-1) contains supplementary material, which is available to authorized users.

The potential of retinoids for combination therapy of lung cancer: Updates and future directions

Lung cancer is the most common cancer-related death worldwide. Natural compounds have shown high biological and pharmaceutical relevance as anticancer agents. Retinoids are natural derivatives of vitamin A having many regulatory functions in the human body, including vision, cellular proliferation and differentiation, and activation of tumour suppressor genes. Retinoic acid (RA) is a highly active retinoid isoform with promising anti-lung cancer activity. The abnormal expression of retinoid receptors is associated with loss of anticancer activities and acquired resistance to RA in lung cancer. The preclinical promise has not translated to the general clinical utility of retinoids for lung cancer patients, especially those with a history of smoking. Newer retinoid nano-formulations and the combinatorial use of retinoids has been associated with lower toxicity and more favorably efficacy in both the preclinical and clinical settings. Here, we highlight epidemiological and clinical therapeutic studies involving retinoids and lung cancer. We also discuss the biological actions of retinoids in lung cancer, which include effects on cancer stem cell differentiation, angiogenesis, metastasis, and proliferative. We suggest that the use of retinoids in combination with conventional and targeted anticancer agents will broaden the utility of these potent anticancer compounds in the lung cancer clinic.

Vitamin D Receptor Activation Reduces Angiotensin-II-Induced Dissecting Abdominal Aortic Aneurysm in Apolipoprotein E-Knockout Mice

OBJECTIVE

Abdominal aortic aneurysm (AAA) is a vascular disorder characterized by chronic inflammation of the aortic wall. Low concentrations of vitamin D3 are associated with AAA development; however, the potential direct effect of vitamin D3 on AAA remains unknown. This study evaluates the effect of oral treatment with the vitamin D3 receptor (VDR) ligand, calcitriol, on dissecting AAA induced by angiotensin-II (Ang-II) infusion in apoE(-/-) mice.

APPROACH AND RESULTS

Oral treatment with calcitriol reduced Ang-II-induced dissecting AAA formation in apoE(-/-) mice, which was unrelated to systolic blood pressure or plasma cholesterol concentrations. Immunohistochemistry and reverse-transcription polymerase chain reaction analysis demonstrated a significant increase in macrophage infiltration, neovessel formation, matrix metalloproteinase-2 and matrix metalloproteinase-9, chemokine (CCL2 [(C-C motif) ligand 2], CCL5 [(C-C motif) ligand 5], and CXCL1 [(C-X-C motif) ligand 1]) and vascular endothelial growth factor expression in suprarenal aortic walls of apoE(-/-) mice infused with Ang-II, and all were significantly reduced by cotreatment with calcitriol. Phosphorylation of extracellular signal-regulated kinases 1/2, p38 mitogen-activated protein kinase, and nuclear factor-κB was also decreased in the suprarenal aortas of apoE(-/-) mice cotreated with calcitriol. These effects were accompanied by a marked increase in VDR-retinoid X receptor (RXR) interaction in the aortas of calcitriol-treated mice. In vitro, VDR activation by calcitriol in human endothelial cells inhibited Ang-II-induced leukocyte-endothelial cell interactions, morphogenesis, and production of endothelial proinflammatory and angiogenic chemokines through VDR-RXR interactions, and knockdown of VDR or RXR abolished the inhibitory effects of calcitriol.

CONCLUSIONS

VDR activation reduces dissecting AAA formation induced by Ang-II in apoE(-/-) mice and may constitute a novel therapeutic strategy to prevent AAA progression.

The natural compound codonolactone impairs tumor induced angiogenesis by downregulating BMP signaling in endothelial cells

BACKGROUND

Angiogenesis, the recruitment of new blood vessels, was demonstrated that is an essential component of the growth of a tumor beyond a certain size and the metastatic pathway. The potential use of angiogenesis-based agents, such as those involving natural and synthetic inhibitors as anticancer drugs is currently under intense investigation. In this study, the anti-angiogenic properties of codonolactone (CLT), a sesquiterpene lactone from Atractylodes lancea, were examined in endothelial cells.

PURPOSE

Our published study reported that CLT shows significant anti-metastatic properties in vitro and in vivo. In order to determine whether angiogenic-involved mechanisms contribute to the anti-metastatic effects of CLT, we checked the anti-angiogenic properties of CLT and its potential mechanisms.

STUDY DESIGN/METHODS

Human umbilical vein endothelial cells (HUVECs) and EA.hy 926 cells were involved in this study. Immunofluorescence assay for cells and immunohistochemistry assay for tissues were used to check the expression of angiogenic markers. In vitro migration and invasion of endothelial cells treated with and without CLT were analyzed. Protein expressions were measured by Western blot analysis. For MMPs activity assay, fluorescence resonance energy transfer-based MMPs activity assay and gelatin zymography assay were involved in this study.

RESULTS

Here we demonstrated that CLT exhibited inhibition on cancer cell induced angiogenesis in vivo, and direct inhibited migration and invasion of endothelial cells in vitro. Moreover, we observed that the down-regulation of MMPs and VEGF-VEGFR2 was involved in the anti-angiogenic effects of CLT. Data from Western blotting showed that, in endothelial cells, CLT reduced Runx2 activation and BMP signaling.

CONCLUSION

Our findings demonstrated that CLT impaired the development of angiogenesis both in vitro and in vivo by direct inhibition on endothelial cells. These inhibitory effects were depended on its ability to interference with BMP signaling in endothelial cells, which may cause inhibition of MMPs expression and VEGF secretion by down-regulating Runx2 activation.

The anthraquinone derivative Emodin inhibits angiogenesis and metastasis through downregulating Runx2 activity in breast cancer

Emodin (EMD) is an anthraquinone derivative extracted from the root and rhizome of Rheum palmatum L. which exhibits a range of activities, including anti-bacterial, antitumor, diuretic and vasorelaxant effects. The ability to inhibit metastasis and angiogenesis was shown in previous pharmacological studies, but clear information to address EMD affecting angiogenesis and metastasis in human breast cancer is still lacking. In the present study, we evaluated a possible role for EMD in angiogenesis and metastasis induced by breast cancer cells. It was revealed here that EMD attenuated tumor cell-induced metastasis and angiogenesis both in vitro and in vivo. Furthermore, it was found that these inhibitory effects were caused by MMPs and VEGFR-2 inhibition in metastatic breast cancer cells and endothelial cells, respectively. Western blot analysis showed reduction of Runx2 activation in the EMD-treated cells. ELISA based Runx2 transcription factor assay showed that the interaction between Runx2 and target sequences was inhibited by EMD. Our findings suggested that the inhibitory effects of EMD on tumor-induced metastasis and angiogenesis were caused by MMPs and VEGFR-2 inhibition, which may be associated with the downregulation of Runx2 transcriptional activity.

NSK-01105, a novel sorafenib derivative, inhibits human prostate tumor growth via suppression of VEGFR2/EGFR-mediated angiogenesis

The purpose of this study is to investigate the anti-angiogenic activities of NSK-01105, a novel sorafenib derivative, in in vitro, ex vivo and in vivo models, and explore the potential mechanisms. NSK-01105 significantly inhibited vascular endothelial growth factor (VEGF)-induced migration and tube formation of human umbilical vein endothelial cells at non-cytotoxic concentrations as shown by wound-healing, transwell migration and endothelial cell tube formation assays, respectively. Cell viability and invasion of LNCaP and PC-3 cells were significantly inhibited by cytotoxicity assay and matrigel invasion assay. Furthermore, NSK-01105 also inhibited ex vivo angiogenesis in matrigel plug assay. Western blot analysis showed that NSK-01105 down-regulated VEGF-induced phosphorylation of VEGF receptor 2 (VEGFR2) and the activation of epidermal growth factor receptor (EGFR). Tumor volumes were significantly reduced by NSK-01105 at 60 mg/kg/day in both xenograft models. Immunohistochemical staining demonstrated a close association between inhibition of tumor growth and neovascularization. Collectively, our results suggest a role of NSK-01105 in treatment for human prostate tumors, and one of the potential mechanisms may be attributed to anti-angiogenic activities.

Vitamin A and retinoid derivatives for lung cancer: a systematic review and meta analysis

BACKGROUND

Despite reported antiproliferative activity of vitamin A and its common use for cancer, there is no comprehensive synthesis of its safety and efficacy in lung cancers. To address this issue we conducted a systematic review of the safety and efficacy of vitamin A for the treatment and prevention of lung cancers.

METHODS AND FINDINGS

Two independent reviewers searched six electronic databases from inception to July 2009 for clinical, observational, and preclinical evidence pertaining to the safety and efficacy of vitamin A and related retinoids for lung cancers. 248 studies were included for full review and analysis. Five RCTs assessed treatment of lung cancers, three assessed primary prevention, and three looked at secondary prevention of lung cancers. Five surrogate studies, 26 phase I/II, 32 observational, and 67 preclinical studies were also included. 107 studies were included for interactions between vitamin A and chemo- or radiation-therapy. Although some studies demonstrated benefits, there was insufficient evidence overall to support the use of vitamin A or related retinoids for the treatment or prevention of lung cancers. Retinyl palmitate combined with beta carotene increased risk of lung cancer in smokers in the large CARET trial. Pooling of three studies pertaining to treatment and three studies on secondary prevention revealed no significant effects on response rate, second primary tumor, recurrence, 5-year survival, and mortality. There was a small improvement in event free survival associated with vitamin A compared to controls, RR 1.24 (95% CI 1.13-1.35). The synthetic rexinoid bexarotene increased survival significantly among a subset of patients in two RCTs (p<0.014, <0.087).

CONCLUSIONS

There is a lack of evidence to support the use of naturally occurring retinoids for the treatment and prevention of lung cancers. The rexinoid bexarotene may hold promise for use among a subset of patients, and deserves further study.

In vitro anti-angiogenic properties of LGD1069, a selective retinoid X-receptor agonist through down-regulating Runx2 expression on Human endothelial cells

Background

LGD1069 (Targretin^®) is a selective retinoid X receptor (RXR) ligand, which is used in patients for cutaneous T-cell lymphoma. Our published study reported that LGD1069 inhibited tumor-induced angiogenesis in non-small cell lung cancer. In present study, we found that LGD1069 suppressed the proliferation, adhesion, invasion and migration of endothelial cells directly, and affected the expression of vegf and some matrix genes.

Methods

Human umbilical vein endothelial cells (HUVECs) were used for in vitro study. MTT assay and Sulforhodamine B assay were used for cell viability assay; the tube formation assay was used to investigate the effect of LGD1069 on angiogenesis in vitro. In vitro adhesion, migration and invasion of HUVEC cells were analyzed by Matrigel adhesion, migration and invasion assay. Gene expressions were measured by RT-PCR and Western blot analysis.

Results

Our data showed here that LGD1069 inhibited the activation of TGF-β/Smad pathway significantly. Furthermore, it was demonstrated that expression of Runx2 was suppressed pronouncedly during incubation with LGD1069. Runx2 is a DNA-binding transcription factor which plays a master role in tumor-induced angiogenesis and cancer cells metastasis by interaction with the TGF-β/Smad pathway of transcriptional modulators.

Conclusions

Our results suggested that LGD1069 may impair angiogenic and metastatic potential induced by tumor cells through suppressing expression of Runx2 directly on human endothelial cells, which may point out new pathway through which LGD1069 display anti-angiogenic properties, and provide new molecular evidence to support LGD1069 as a potent anti-metastatic agent in cancer therapy.

Use of the in vivo hollow fiber assay in natural products anticancer drug discovery

The in vivo hollow fiber assay was developed at the National Cancer Institute (NCI) to help bridge the gap between in vitro cell-based assays and human tumor models propagated in immunodeficient mice. The goal was to develop an intermediate assay that could help predict which compounds found active in the 60-cell line panel would be active in a subsequent xenograft system. This was necessary due to the high cost of the traditional xenograft assay in terms of number of animals required, time for assay completion, and financial commitment necessary. To address this problem, investigators of the NCI Developmental Therapeutics Program designed a method of propagating human cancer cells in inert hollow fibers with pores small enough to retain the cancer cells but large enough to permit entry of potential chemotherapeutic drugs, including large proteins and other important substances. Fibers containing proliferating cancer cells are transplanted into the peritoneum or under the skin, the host mice are treated with a test agent, and the fibers are subsequently retrieved for analysis of viable cell mass. The assay has been successful in helping investigators from around the world, including our own research group, prioritize compounds active in vitro for further testing in the traditional xenograft system.

In vivo and microarray analysis of rexinoid-responsive anaplastic thyroid carcinoma

PURPOSE

Anaplastic thyroid carcinoma is rare, yet lethal despite aggressive therapy. Molecular targeting may be beneficial using the rexinoid LGD1069, a retinoid X receptor-selective agonist, as a novel treatment. In this report, we describe the efficacy of LGD1069 in anaplastic thyroid carcinoma in vitro and assess the in vivo treatment effects on a responsive cancer. Additionally, we explore potential mediators of the rexinoid effect on a responsive anaplastic thyroid cancer using comparative microarray analysis.

EXPERIMENTAL DESIGN

Anaplastic thyroid cancer cell lines DRO, ARO, and FRO were treated with LGD1069 in vitro. Responsive DRO xenograft tumors were treated with control chow or chow containing a low dose (30 mg/kg/d) or a high dose (100 mg/kg/d) of LGD1069. Comparative microarray analysis of DRO cells treated with LGD1069 compared with volume-equivalent control was assessed after 24 h of treatment to evaluate early gene expression changes.

RESULTS

DRO xenograft tumor growth was inhibited by LGD1069 treatment in a dose-dependent manner. Comparative microarray analysis showed that 80 genes had a significant increase in expression and 29 genes had a decrease in expression after 24 h of treatment with LGD1069. Expression of angiopoietin-like 4 (ANGPTL4) mRNA was increased 6.5-fold. A trend towards an increase in ANGPTL4 mRNA (not statistically significant) was seen in treated tumors in vivo and this correlated with decreased tumor vascularity and increased necrosis.

CONCLUSIONS

LGD1069 therapy decreases proliferation in an anaplastic thyroid cancer cell line that expresses retinoid X receptor-gamma, and this effect is confirmed with decreased tumor size in vivo in a nude mouse model. ANGPTL4 is increased in DRO in response to LGD1069 and may be a potential mediator of the effects of rexinoid treatment.