Dimethylfumarate effectively inhibits lymphangiogenesis via p21 induction and G1 cell cycle arrest

Tumor lymphangiogenesis index reveals the immune landscape and immunotherapy response in lung adenocarcinoma

Background

Lymphangiogenesis (LYM) has an important role in tumor progression and is strongly associated with tumor metastasis. However, the clinical application of LYM has not progressed as expected. The potential value of LYM needs to be further developed in lung adenocarcinoma (LUAD) patients.

Methods

The Sequencing data and clinical characteristics of LUAD patients were downloaded from The Cancer Genome Atlas and GEO databases. Multiple machine learning algorithms were used to screen feature genes and develop the LYM index. Immune cell infiltration, immune checkpoint expression, Tumor Immune Dysfunction and Exclusion (TIDE) algorithm and drug sensitivity analysis were used to explore the correlation of LYM index with immune profile and anti-tumor therapy.

Results

We screened four lymphangiogenic feature genes (PECAM1, TIMP1, CXCL5 and PDGFB) to construct LYM index based on multiple machine learning algorithms. We divided LUAD patients into the high LYM index group and the low LYM index group based on the median LYM index. LYM index is a risk factor for the prognosis of LUAD patients. In addition, there was a significant difference in immune profile between high LYM index and low LYM index groups. LUAD patients in the low LYM index group seemed to benefit more from immunotherapy based on the results of TIDE algorithm.

Conclusion

Overall, we confirmed that the LYM index is a prognostic risk factor and a valuable predictor of immunotherapy response in LUAD patients, which provides new evidence for the potential application of LYM.

Roles of Glutathione and AP-1 in the Enhancement of Vitamin D-Induced Differentiation by Activators of the Nrf2 Signaling Pathway in Acute Myeloid Leukemia Cells

Active vitamin D derivatives (VDDs)-1α,25-dihydroxyvitamin D3/D2 and their synthetic analogs-are well-known inducers of cell maturation with the potential for differentiation therapy of acute myeloid leukemia (AML). However, their dose-limiting calcemic activity is a significant obstacle to using VDDs as an anticancer treatment. We have shown that different activators of the NF-E2-related factor-2/Antioxidant Response Element (Nrf2/ARE) signaling pathway, such as the phenolic antioxidant carnosic acid (CA) or the multiple sclerosis drug monomethyl fumarate (MMF), synergistically enhance the antileukemic effects of various VDDs applied at low concentrations in vitro and in vivo. This study aimed to investigate whether glutathione, the major cellular antioxidant and the product of the Nrf2/ARE pathway, can mediate the Nrf2-dependent differentiation-enhancing activity of CA and MMF in HL60 human AML cells. We report that glutathione depletion using L-buthionine sulfoximine attenuated the enhancing effects of both Nrf2 activators concomitant with downregulating vitamin D receptor (VDR) target genes and the activator protein-1 (AP-1) family protein c-Jun levels and phosphorylation. On the other hand, adding reduced glutathione ethyl ester to dominant negative Nrf2-expressing cells restored both the suppressed differentiation responses and the downregulated expression of VDR protein, VDR target genes, as well as c-Jun and P-c-Jun levels. Finally, using the transcription factor decoy strategy, we demonstrated that AP-1 is necessary for the enhancement by CA and MMF of 1α,25-dihydroxyvitamin D3-induced VDR and RXRα protein expression, transactivation of the vitamin D response element, and cell differentiation. Collectively, our findings suggest that glutathione mediates, at least in part, the potentiating effect of Nrf2 activators on VDDs-induced differentiation of AML cells, likely through the positive regulation of AP-1.

Advances in Drugs Targeting Lymphangiogenesis for Preventing Tumor Progression and Metastasis

Metastasis of cancer cells from the primary tumor to other organs and tissues in the body is the leading cause of death in patients with malignancies. One of the principal ways cancer cells travel is through lymphatic vessels, and tumor invasion into the regional lymph nodes is a hallmark of early metastasis; thus, the formation of especially peritumoral lymphatic vessels is essential for tumor transportation that gives rise to further progression. In the past few decades, tumor-induced lymphangiogenesis has been testified to its tight correlation with lymphatic metastasis and poor clinical outcomes in multiple types of human malignancies, which warrants novel potential therapeutic targets for cancer treatment. As the understanding of underlying molecular mechanisms has grown tremendously over the years, an inexorable march of anti-lymphangiogenic therapy also aroused terrific interest. As a result, a great number of drugs have entered clinical trials, and some of them exhibited predominant contributions in cancer management. Herein, this review provides an updated summary of the current advances in therapies preventing lymphatic metastasis and discusses the validity of different applications.

Drug Repurposing for Glioblastoma and Current Advances in Drug Delivery-A Comprehensive Review of the Literature

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults with an extremely poor prognosis. There is a dire need to develop effective therapeutics to overcome the intrinsic and acquired resistance of GBM to current therapies. The process of developing novel anti-neoplastic drugs from bench to bedside can incur significant time and cost implications. Drug repurposing may help overcome that obstacle. A wide range of drugs that are already approved for clinical use for the treatment of other diseases have been found to target GBM-associated signaling pathways and are being repurposed for the treatment of GBM. While many of these drugs are undergoing pre-clinical testing, others are in the clinical trial phase. Since GBM stem cells (GSCs) have been found to be a main source of tumor recurrence after surgery, recent studies have also investigated whether repurposed drugs that target these pathways can be used to counteract tumor recurrence. While several repurposed drugs have shown significant efficacy against GBM cell lines, the blood–brain barrier (BBB) can limit the ability of many of these drugs to reach intratumoral therapeutic concentrations. Localized intracranial delivery may help to achieve therapeutic drug concentration at the site of tumor resection while simultaneously minimizing toxicity and side effects. These strategies can be considered while repurposing drugs for GBM.

The functional roles of TCA cycle metabolites in cancer

The tricarboxylic acid cycle (TCA cycle) has been known for decades as a hub for generating cellular energy and precursors for biosynthetic pathways. Several cancers harbor mutations that affect the integrity of this cycle, mostly at the levels of isocitrate dehydrogenase (IDH), succinate dehydrogenase (SDH), and fumarate hydratase (FH). This results in dysregulation in the production of TCA cycle metabolites and is probably implicated in cancer initiation. By modulating cellular activities, including metabolism and signaling, TCA cycle intermediates are able to impact the processes of cancer development and progression. In this review, we discuss the functional roles of the TCA cycle intermediates in suppressing or promoting the progression of cancers. A further understanding of TCA metabolites' roles and molecular mechanisms in oncogenesis would prompt developing novel metabolite-based cancer therapy in the future.

Subconjunctival injections of dimethyl fumarate inhibit lymphangiogenesis and allograft rejection in the rat cornea

Corneal lymphangiogenesis induced by macrophages played a critical role in corneal allograft rejection (CGR). However, there are few Food and Drug Administration (FDA)-approved drugs that target lymphangiogenesis. The aim of our study is to evaluate the effects of dimethyl fumarate (DMF) on corneal allograft survival in rats. Penetrating corneal transplantation was performed in rats. Subconjunctival injections of dimethyl fumarate (20 µg) were administered at the end of the operation and postoperative day 3 to day 11. The clinical signs of corneal allografts were evaluated. Immunohistochemistry, quantitative real-time PCR (qPCR), flow cytometry and western blot were performed respectively. The effects and mechanism of DMF on RAW264.7 cells were determined by qPCR, enzyme-linked immunosorbent assay (ELISA), and western blot in vitro. The results showed that subconjunctival injections of DMF could significantly inhibit corneal lymphangiogenesis and CGR with decreased corneal macrophage infiltration compared with the vehicle group. Moreover, DMF could reduce the mRNA expression of monocyte chemoattractant protein 1 (MCP-1), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and vascular endothelial growth factor-C (VEGF-C) in the corneal grafts and RAW264.7 macrophages by inhibiting NF-κB activation. Furthermore, compared with the vehicle group, the number of dendritic cells in the ipsilateral cervical lymph nodes of the DMF-treated group was decreased significantly. Collectively, our findings showed that DMF could suppress CGR by inhibiting the macrophage-induced corneal lymphoangiogenesis.

Phase I trial of dimethyl fumarate, temozolomide, and radiation therapy in glioblastoma

Background

Dimethyl fumarate (DMF), an oral agent approved for the treatment of relapsing–remitting multiple sclerosis (RRMS), has promising preclinical activity against glioblastoma (GBM). This phase I study sought to determine the recommended phase 2 dose (RP2D) of DMF and evaluate its safety and toxicity when combined with standard concurrent radiotherapy (RT) and temozolomide (TMZ) followed by maintenance TMZ in patients with newly diagnosed GBM.

Methods

Using a standard 3 + 3 dose-escalation design with 3 dose levels, patients received daily DMF with 60 Gy RT and concurrent TMZ 75 mg/m² daily, followed by maintenance DMF (continuously) and TMZ 150–200 mg/m² on days 1–5 of each 28-day cycle for up to 6 cycles. The maximum tolerated dose (MTD) was determined by evaluation of dose-limiting toxicity (DLT) during the first 6 weeks of therapy.

Results

Twelve patients were treated at the 3 dose levels, and no DLTs were observed. There were no unexpected toxicities. The most common grade 3/4 treatment related adverse events (AEs) were lymphopenia (58%), decreased CD4 count (17%), and thrombocytopenia (17%). Four patients completed all planned treatment; seven patients had progression on treatment. One patient chose to withdraw from the study during maintenance. The median progression-free survival (PFS) for all patients was 8.7 months with no difference in PFS between those with stable disease or a partial response; median overall survival was 13.8 months.

Conclusions

DMF may be safely combined with RT and TMZ in patients with newly diagnosed GBM. The RP2D for DMF is 240 mg three times daily.

Dimethylfumarate Inhibits Colorectal Carcinoma Cell Proliferation: Evidence for Cell Cycle Arrest, Apoptosis and Autophagy

Recent studies have proven that Dimethylfumarate (DMF) has a marked anti-proliferative impact on diverse cancer entities e.g., on malignant melanoma. To explore its anti-tumorigenic potential, we examined the effects of DMF on human colon carcinoma cell lines and the underlying mechanisms of action. Human colon cancer cell line HT-29 and human colorectal carcinoma cell line T84 were treated with or without DMF. Effects of DMF on proliferation, cell cycle progression, and apoptosis were analyzed mainly by Bromodeoxyuridine (BrdU)- and Lactatdehydrogenase (LDH)assays, caspase activation, flowcytometry, immunofluorescence, and immunoblotting. In addition, combinational treatments with radiation and chemotherapy were performed. DMF inhibits cell proliferation in both cell lines. It was shown that DMF induces a cell cycle arrest in G0/G1 phase, which is accompanied by upregulation of p21 and downregulation of cyclin D1 and Cyclin dependent kinase (CDK)4. Furthermore, upregulation of autophagy associated proteins suggests that autophagy is involved. In addition, the activation of apoptotic markers provides evidence that apoptosis is involved. Our results show that DMF supports the action of oxaliplatin in a synergetic manner and failed synergy with radiation. We demonstrated that DMF has distinct antitumorigenic, cell dependent effects on colon cancer cells by arresting cell cycle in G0/G1 phase as well as activating both the autophagic and apoptotic pathways and synergizes with chemotherapy.

Bergapten induces G1 arrest of non‑small cell lung cancer cells, associated with the p53‑mediated cascade

The principal subtype of lung cancer, non‑small cell lung cancer (NSCLC) is a life‑threatening malignancy that causes high mortality rates. Bergapten (5‑methoxypsoralen) has been identified to possess anticancer activity against a number of carcinomas. In the present study, the effects of bergapten on NSCLC cells were investigated. The cell viability was determined by MTT assay. Cell cycle distribution was analyzed using flow cytometry. Protein expression and kinase cascade were demonstrated using western blot analysis. The results demonstrated that treatment with bergapten (50 µM for 48 h) inhibited the viability of A549 and NCI‑H460 NSCLC cells to 79.1±2.8% and 74.5±3.1%, respectively, compared with the controls. It was identified that bergapten induced G1 phase accumulation in A549 and NCI‑H460 cells between ~58 and 75% (P<0.01). In addition, bergapten significantly increased the sub‑G1 phase ratio to ~9% (P<0.05) in the two cell types. Further investigation demonstrated that bergapten upregulated the expression of cellular tumor antigen p53 (p53) and its downstream proteins cyclin‑dependent kinase inhibitor 1 and cyclin‑dependent kinase inhibitor 1B, whereas, it downregulated the expression of cyclin D1 and CDK4. Overall, these results suggested that bergapten may inhibit cell viability and trigger G1 arrest and apoptosis in A549 and NCI‑H460 cells, which may be attributed to the activation of p53‑mediated cascades. Therefore, bergapten may be beneficial for NSCLC treatment.

The Protective Role of Selenium in AFB1-Induced Tissue Damage and Cell Cycle Arrest in Chicken's Bursa of Fabricius

Aflatoxin B₁ (AFB₁) is a naturally occurring secondary metabolites of Aspergillus flavus and Aspergillus parasiticus, and is the most toxic form of aflatoxins. Selenium (Se) with antioxidant and detoxification functions is one of the essential trace elements for human beings and animals. This study aims to evaluate the protective effects of Se on AFB₁-induced tissue damage and cell cycle arrest in bursa of Fabricius (BF) of chickens. The results showed that a dietary supplement of 0.4 mg·kg^-1 Se alleviated the histological lesions induced by AFB₁, as demonstrated by decreasing vacuoles and nuclear debris, and relieving oxidative stress. Furthermore, flow cytometry studies showed that a Se supplement protected AFB₁-induced G₂M phase arrest at 7 days and G₀G₁ phase arrest at 14 and 21 days. Moreover, the mRNA expression results of ATM, Chk2, p53, p21, cdc25, PCNA, cyclin D₁, cyclin E₁, cyclin B₃, CDK6, CDK2, and cdc2 indicated that Se supplement could restore these parameters to be close to those in the control group. It is concluded that a dietary supplement of 0.4 mg kg^-1 Se could diminish AFB₁-induced immune toxicity in chicken's BF by alleviating oxidative damage and cell cycle arrest through an ATM-Chk2-cdc25 route and the ATM-Chk2-p21 pathway.

The molecular mechanism of cell cycle arrest in the Bursa of Fabricius in chick exposed to Aflatoxin B 1

Aflatoxin B₁ shows potent hepatotoxic, carcinogenic, genotoxic, immunotoxic potential in humans and many species of animals. The aim of this study was to clarify the underlying mechanism of G₀G₁ phase and G₂M phase arrest of cell cycle in the bursa of Fabricius in broilers exposed to dietary AFB₁. 144 one-day-old healthy Cobb broilers were randomly divided into two groups and fed on control diet and 0.6 mg·Kg⁻¹ AFB₁ diet for 3 weeks. Histological observation showed that AFB₁ induced the increase of nuclear debris and vacuoles in lymphoid follicle of BF. Results of flow cytometry studies showed that bursal cells arrested in G₂M phase at 7 days of age and blocked in G₀G₁ phase at 14 and 21 days of age following exposure to AFB₁. The qRT-PCR analysis indicated that cell cycle arrested in G₂M phase via ATM-Chk2-cdc25-cyclin B/cdc2 pathway, and blocked in G₀G₁ phase through ATM-Chk2-cdc25-cyclin D/CDK6 pathway and ATM-Chk2-p21-cyclin D/CDK6 route. In a word, our results provided new insights that AFB₁ diet induced G₂M and G₀G₁ phase blockage of BF cells in different periods, and different pathways were activated in different arrested cell cycle phase.

Co‑expression of murine double minute 2 siRNA and wild‑type p53 induces G1 cell cycle arrest in H1299 cells

The therapeutic options available for the treatment of advanced non-small cell lung cancer have increased over the past decade. Small molecule gene therapy has emerged as an effective therapy for the treatment of lung cancer in vitro and in vivo although it has not been tested in a clinical setting. In particular, therapies that target the negative feedback loop between p53 and murine double minute 2 (MDM2) provide a favorable outcome by maintaining activation of the tumor suppressor gene p53. The present study used transfection to simultaneously knockdown MDM2 expression using small interfering (si)RNA, and overexpress wild‑type p53 in H1299 cells. The effects of transfection on cell proliferation and cell cycle progression were determined using an MTT assay and flow cytometry, and the effects on mRNA and protein expression were determined by western blotting and reverse transcription polymerase chain reaction. The results indicated that simultaneously knocking down MDM2 and overexpressing p53 was able to inhibit proliferation and induce G1 cell cycle arrest in H1299 cells, compared with either alone. These findings indicated that the si‑MDM2‑p53 co‑expression plasmid may induce cell cycle arrest, and may be considered a novel therapeutic option for the treatment of lung cancer.

Dimethylfumarate inhibits melanoma cell proliferation via p21 and p53 induction and bcl-2 and cyclin B1 downregulation

Recent evidence suggests that dimethylfumarate (DMF), known as a highly potent anti-psoriatic agent, might have anti-tumorigenic properties in melanoma. It has recently been demonstrated that DMF inhibits melanoma proliferation by apoptosis and cell cycle inhibition and therefore inhibits melanoma metastasis. Nonetheless, the underlying mechanisms remain to be evaluated. To elucidate the effects of DMF on melanoma cell lines (A375, SK-Mel), we first performed cytotoxicity assays. No significant lactatedehydogenase (LDH) release could be found. In further analysis, we showed that DMF suppresses melanoma cell proliferation in a concentration-dependent manner. To examine whether these effects are conveyed by apoptotic mechanisms, we studied the amount of apoptotic nucleosomes and caspase 3/7 activity using ELISA analysis. Significant apoptosis was induced by DMF in both cell lines, and this could be paralleled with bcl-2 downregulation and PARP-1 cleavage. We also performed cell cycle analysis and found that DMF induced concentration-dependent arrests of G0/G1 as well as G2/M. To examine the underlying mechanisms of cell cycle arrest, we analyzed the expression profiles of important cell cycle regulator proteins such as p53, p21, cyclins A, B1, and D1, and CDKs 3, 4, and 6. Interestingly, DMF induced p53 and p21 yet inhibited cyclin B1 expression in a concentration-dependent manner. Other cell cycle regulators were not influenced by DMF. The knockdown of DMF induced p53 via siRNA led to significantly reduced apoptosis but had no influence on cell cycle arrest. We examined the adhesion of melanoma cells on lymphendothelial cells during DMF treatment and found a significant reduction in interaction. These data provide evidence that DMF inhibits melanoma proliferation by reinduction of important cell cycle inhibitors leading to a concentration-dependent G0/G1 or G2/M cell cycle arrest and induction of apoptosis via downregulation of bcl-2 and induction of p53 and PARP-1 cleavage. Hence, DMF might be an interesting agent in the treatment of melanoma and is worth further investigation in vivo.