Targeted knockdown of DJ-1 induces multiple myeloma cell death via KLF6 upregulation

Acquired Bortezomib Resistance in Multiple Myeloma: From Mechanisms to Strategy

OPINION STATEMENT

Multiple myeloma (MM) is a heterogeneous plasma cell tumor with a survival period of several months to over ten years. Despite the development of various new drugs, MM is still incurable and recurs repeatedly. Bortezomib, a landmark event in the history of MM treatment, has dramatically improved the prognosis of patients with MM. Although proteasome inhibitors (PIs) represented by bortezomib, have greatly prolonged MM survival, unfortunately, almost all MM will develop bortezomib resistance, leading to relapse with a shorter survival. It has been reported that both the tumor microenvironment and myeloma cells drive bortezomib resistance. Multiple treatment methods have been attempted to overcome bortezomib resistance, but unfortunately, there has been no breakthrough. It is believed that the key resistance mechanism has not yet been discovered. A deeper understanding of the mechanism of bortezomib resistance and strategies to overcome it can help identify key resistance mechanisms and further improve the prognosis of MM.

DJ-1-mediated p62 degradation delays intervertebral disc degeneration by inhibiting apoptosis of nucleus pulposus cells

Intervertebral disc degeneration (IDD) is the most important pathological basis of degenerative spinal diseases, for which effective interventions are still lacking. Oxidative stress is considered to be one of the leading pathological mechanisms contributing to IDD. However, the exact role of DJ-1 as an essential member of the antioxidant defense system in IDD is still unclear. Therefore, the aim of this study was to investigate the role played by DJ-1 in IDD and to reveal its potential molecular mechanisms. Western blot and immunohistochemical staining assays were performed to detect the expression of DJ-1 in degenerative nucleus pulposus cells (NPCs). After overexpression of DJ-1 in NPCs by lentiviral transfection, DCFH-DA and MitoSOX fluorescent probes were used to evaluate the levels of reactive oxygen species (ROS); while western blot, TUNEL staining, and Caspase-3 activity were used to assess apoptosis. Immunofluorescence staining was used to demonstrate the relationship between DJ-1 and p62. After inhibition of lysosomal degradation function with chloroquine, p62 degradation and apoptosis in DJ-1 overexpressing NPCs were further examined. In vivo, we assessed the therapeutic effect of upregulated DJ-1 on IDD by X-ray, MRI and Safranin O-Fast green staining. The protein expression of DJ-1 was significantly decreased in degenerated NPCs, accompanied by increased apoptosis. However, overexpression of DJ-1 significantly inhibited the elevated ROS levels and apoptosis in NPCs under oxidative stress. Mechanistically, our results showed that upregulation of DJ-1 promoted p62 degradation via the autophagic lysosomal pathway and that the protective effect of DJ-1 on NPCs under oxidative stress was partially mediated by promoting lysosomal pathway degradation of p62. Moreover, intradiscal injection of adeno-associated virus for overexpression of DJ-1 mitigated the progression of IDD in rats. This study reveals that DJ-1 maintains the homeostasis of NPCs by promoting the degradation of p62 through the autophagic lysosomal pathway, suggesting that DJ-1 is a promising new target for IDD intervention.

Induction of RIPK3/MLKL-mediated necroptosis by Erigeron breviscapus injection exhibits potent antitumor effect

Colorectal cancer (CRC) is the second leading cause of tumor-related deaths worldwide. Resistance of tumor cells to drug-induced apoptosis highlights the need for safe and effective antitumor alternatives. Erigeron breviscapus (Dengzhanxixin in China) injection (EBI), extracted from the natural herb Erigeron breviscapus (Vant.) Hand.-Mazz (EHM), has been widely used in clinical practice for cardiovascular diseases. Recent studies have suggested that EBI's main active ingredients exhibit potential antitumor effects. This study aims to explore the anti-CRC effect of EBI and elucidate the underlying mechanism. The anti-CRC effect of EBI was evaluated in vitro using CCK-8, flow cytometry, and transwell analysis, and in vivo through a xenograft mice model. RNA sequencing was utilized to compare the differentially expressed genes, and the proposed mechanism was verified through in vitro and in vivo experiments. Our study demonstrates that EBI significantly inhibits the proliferation of three human CRC cell lines and effectively suppresses the migration and invasion of SW620 cells. Moreover, in the SW620 xenograft mice model, EBI markedly retards tumor growth and lung metastasis. RNA-seq analysis revealed that EBI might exert antitumor effects by inducing necroptosis of tumor cells. Additionally, EBI activates the RIPK3/MLKL signaling pathway, a classical pathway of necroptosis and greatly promotes the generation of intracellular ROS. Furthermore, the antitumor effect of EBI on SW620 is significantly alleviated after the pretreatment of GW806742X, the MLKL inhibitor. Our findings suggest that EBI is a safe and effective inducer of necroptosis for CRC treatment. Notably, necroptosis is a non-apoptotic programmed cell death pathway that can effectively circumvent resistance to apoptosis, which provides a novel approach for overcoming tumor drug resistance.

PARK7/DJ-1 inhibition decreases invasion and proliferation of uveal melanoma cells

INTRODUCTION

PARK7/DJ-1 is an oncogene that is associated with tumorigenesis in many cancers. Recent studies have demonstrated the importance of DJ-1 in the origin and development of uveal melanoma (UM). We present an analysis of the role of the DJ-1 protein in UM cells, especially in its effect on proliferation and migration.

METHODS

UM cells from a primary tumor, Mel 270, and its liver metastasis, OMM2.5, were transfected with lentiviral-delivered shRNA against PARK7/DJ-1. Evaluation of cell migration and proliferation was performed using the xCELLigence real-time cell analyzer (RTCA). The effect of DJ-1 inhibition on the PTEN-Akt signaling pathway was also studied by immunoblotting.

RESULTS

The silencing of PARK7/DJ-1 oncoprotein expression produced a significant decrease of phosphorylated Akt (S473) in Mel270 and in metastatic OMM2.5 UM cells with no alteration on tumor suppressor PTEN expression. The diminution of PARK7/DJ-1 expression significantly inhibited real-time proliferation and invasion of Mel270 and OMM2.5 and the invasion potential of the metastatic cells.

CONCLUSION

DJ-1 appears to play a key role on the PTEN/Akt pathway in UM. DJ-1 inhibition appears to have a negative effect on proliferation and invasion of UM cells. This suggests DJ-1 as a potential therapeutic target in UM.

Dampened Inflammation and Improved Survival After CXCL5 Administration in Murine Lupus via Myeloid and Neutrophil Pathways

OBJECTIVE

To determine the efficacy of CXCL5 administration in lupus-prone MRL/lpr (Fas^lpr ) mice and elucidate its working mechanisms.

METHODS

CXCL5 expression in blood (obtained from SLE patients and Fas^lpr mice) and major internal organs (obtained from Fas^lpr mice) was examined by Luminex, real-time polymerase chain reaction, and immunofluorescent staining analyses. Pharmacokinetic studies were performed in Fas^lpr mice and healthy Institute of Cancer Research mice. Efficacy of CXCL5 administration was demonstrated in Fas^lpr mice, and the working mechanism of CXCL5 treatment was elucidated by flow cytometry, Luminex, and RNA sequencing.

RESULTS

In SLE patients, serum CXCL5 levels were significantly lower than in healthy individuals (P < 0.0001) and negatively correlated with disease activity (P = 0.004). In Fas^lpr mice, disease severity progressed with age and was negatively associated with plasma CXCL5 levels. Intravenous administration of CXCL5 to Fas^lpr mice restored endogenous circulatory CXCL5, improved mice survival, and reduced anti-double-stranded DNA antibodies, proteinuria, lupus nephritis activity and chronicity indices, renal complements, and neutrophil extracellular traps over short-term (10 weeks) and long-term (2 years) time periods. In vitro and in vivo assays demonstrated that CXCL5 dictated neutrophil trafficking and suppressed neutrophil activation, degranulation, proliferation, and renal infiltration. Renal and splenic RNA sequencing further showed that CXCL5-mediated immunomodulation occurred by promoting energy production in renal-infiltrated immune cells, activating certain T cells, and reducing tissue fibrosis, granulocyte extravasation, complement components, and interferons. Further factorial design results indicated that CXCL5 appears to enhance host tolerability to cyclophosphamide in vulnerable individuals.

CONCLUSION

We found that serum CXCL5 levels were significantly lower in SLE patients than in healthy individuals and were negatively correlated with disease activity. By administering CXCL5 intravenously in a mouse model of lupus, mouse survival improved, and indices of disease activity reduced significantly. Taken together, these findings indicate CXCL5 administration may represent a novel myeloid/neutrophil-targeting therapy for SLE.

Bortezomib induces methylation changes in neuroblastoma cells that appear to play a significant role in resistance development to this compound

The anticancer activity of bortezomib (BTZ) has been increasingly studied in a number of indications and promising results for the use of this treatment have been shown in neuroblastoma. As BTZ treatment is usually administered in cycles, the development of resistance and side effects in patients undergoing therapy with BTZ remains a major challenge for the clinical usage of this compound. Common resistance development also means that certain cells are able to survive BTZ treatment and bypass molecular mechanisms that render BTZ anticancer activity. We studied the methylome of neuroblastoma cells that survived BTZ treatment. Our results indicate that BTZ induces pronounced genome wide methylation changes in cells which recovered from the treatment. Functional analyses of identified methylation changes demonstrated they were involved in key cancer pathology pathways. These changes may allow the cells to bypass the primary anticancer activity of BTZ and develop a treatment resistant and proliferative phenotype. To study whether cells surviving BTZ treatment acquire a proliferative phenotype, we repeatedly treated cells which recovered from the first round of BTZ treatment. The repetitive treatment led to induction of the extraordinary proliferative potential of the cells, that increased with subsequent treatments. As we did not observe similar effects in cells that survived treatment with lenalidomide, and non-treated cells cultured under the same experimental conditions, this phenomenon seems to be BTZ specific. Overall, our results indicate that methylation changes may play major role in the development of BTZ resistance.

A narrative review of the role of necroptosis in liver disease: a double-edged sword

Acute and chronic liver injuries lead to hepatocyte death and turnover. When injuries become chronic, continuous cell death and transformation lead to chronic inflammation, fibrosis, cirrhosis, and eventually carcinoma. A therapeutic strategy of great significance for liver disease is to control hepatocyte death in acute and chronic injuries. This strategy prevents hepatocytes from causing liver failure and inhibits both secondary inflammation and fibrosis. Both apoptosis and necrosis have been proven to occur in the liver, but the role of necroptosis in liver diseases is controversial. Necroptosis, which has features of necrosis and apoptosis, is a regulatory process that occurs in some cell types when caspases are inhibited. The signaling pathway of necroptosis is characterized by the activation of receptor-interacting proteins kinase (RIPK) and mixed lineage kinase domain-like (MLKL). Necroptosis is associated with a variety of inflammatory diseases and has been the focus of research in recent years. The incidence of necroptosis in liver tissues has been studied recently in several liver injury models, but the results of the studies are not consistent. The purpose of this review is to summarize the published data on the involvement of necroptosis in liver injury, focusing on the controversies, issues remaining to be discussed, and potential therapeutic applications in this area.

Novel Insights into PARK7 (DJ-1), a Potential Anti-Cancer Therapeutic Target, and Implications for Cancer Progression

The expression of PARK7 is upregulated in various types of cancer, suggesting its potential role as a critical regulator of the pathogenesis of cancer and in the treatment of cancer and neurodegenerative diseases, including Parkinson’s disease, Alzheimer’s disease, and Huntington disease. PARK7 activates various intracellular signaling pathways that have been implicated in the induction of tumor progression, which subsequently enhances tumor initiation, continued proliferation, metastasis, recurrence, and resistance to chemotherapy. Additionally, secreted PARK7 has been identified as a high-risk factor for the pathogenesis and survival of various cancers. This review summarizes the current understanding of the correlation between the expression of PARK7 and tumor progression.

Identification of chlorprothixene as a potential drug that induces apoptosis and autophagic cell death in acute myeloid leukemia cells

Although acute myeloid leukemia (AML) is a highly heterogeneous malignance, the common molecular mechanisms shared by different AML subtypes play critical roles in AML development. It is possible to identify new drugs that are effective for various AML subtypes based on the common molecular mechanisms. Therefore, we developed a hypothesis-driven bioinformatic drug screening framework by integrating multiple omics data. In this study, we identified that chlorprothixene, a dopamine receptor antagonist, could effectively inhibit growth of AML cells from different subtypes. RNA-seq analysis suggested that chlorprothixene perturbed a series of crucial biological processes such as cell cycle, apoptosis, and autophagy in AML cells. Further investigations indicated that chlorprothixene could induce both apoptosis and autophagy in AML cells, and apoptosis and autophagy could act as partners to induce cell death cooperatively. Remarkably, chlorprothixene was found to inhibit tumor growth and induce in situ leukemic cell apoptosis in the murine xenograft model. Furthermore, chlorprothixene treatment could reduce the level of oncofusion proteins PML-RARα and AML1-ETO, thus elevate the expression of apoptosis-related genes, and lead to AML cell death. Our results provided new insights for drug repositioning of AML therapy and confirmed that chlorprothixene might be a potential candidate for treatment of different subtypes of AML by reducing expression of oncofusion proteins. DATABASE: RNA-seq data are available in GEO database under the accession number GSE124316.

The Multifaceted Roles of DJ-1 as an Antioxidant

The DJ-1 protein was originally linked with Parkinson's disease and is now known to have antioxidant functions. The protein has three redox-sensitive cysteine residues, which are involved in its dimerisation and functional properties. A mildly oxidised form of DJ-1 is the most active form and protects cells from oxidative stress conditions. DJ-1 functions as an antioxidant through a variety of mechanisms, including a weak direct antioxidant activity by scavenging reactive oxygen species. DJ-1 also regulates a number of signalling pathways, including the inhibition of apoptosis signal-regulating kinase 1 (ASK1)-induced apoptosis under oxidative stress conditions. Other proteins regulated by DJ-1 include enzymes, chaperones, the 20S proteasome and transcription factors, including Nrf2. Once activated by oxidative stress, Nrf2 upregulates antioxidant gene expression including members of the thioredoxin and glutathione pathways, which in turn mediate an antioxidant protective function. Crosstalk between DJ-1 and both the thioredoxin and glutathione systems has also been identified. Thioredoxin reduces a cysteine residue on DJ-1 to modulate its activity, while glutaredoxin1 de-glutathionylates DJ-1, preventing degradation of DJ-1 and resulting in its accumulation. DJ-1 also regulates the activity of glutamate cysteine ligase, which is the rate-limiting step for glutathione synthesis. These antioxidant functions of DJ-1 are key to its role in protecting neurons from oxidative stress and are hypothesised to protect the brain from the development of neurodegenerative diseases such as Parkinson's disease (PD) and to protect cardiac tissues from ischaemic-reperfusion injury. However, DJ-1, as an antioxidant, also protects cancer cells from undergoing oxidative stress-induced apoptosis.

DJ-1 Alleviates Angiotensin II-Induced Endothelial Progenitor Cell Damage by Activating the PPARγ/HO-1 Pathway

There is evidence that angiotensin II (Ang II) may impair the functions of endothelial progenitor cells (EPCs). It was revealed that DJ-1 could resist oxidative stress. In this study, we investigated whether DJ-1 could protect EPCs against Ang II-induced cell damage. The proliferation and migration of EPCs were strongly reduced in the Ang II group and were increased by overexpression of DJ-1. Western blotting indicated that the increased expression of the senescence marker β-galactosidase and decreased expression of adhesion molecules (ICAM-1, VCAM-1) induced by Ang II were reversed after Ad-DJ-1 transfection. The reduced angiogenic capacity of EPCs caused by Ang II was also improved after Ad-DJ-1 transfection. Moreover, Ang II significantly increased the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and inflammatory cytokines (TNF-α and IL-1β), reduced the levels of superoxide dismutase (SOD), glutathione (GSH), and these were reversed by Ad-DJ-1 transfection. Expression of peroxisome proliferator-activated receptor-γ (PPARγ) and heme oxygenase (HO-1) was increased by DJ-1. Therefore, HO-1 siRNA were constructed and transfected into EPCs, and the results showed that HO-1 siRNA transfection inhibited the effects of DJ-1 on EPC function. Thus, our study implies that DJ-1 may protect EPCs against Ang II-induced dysfunction by activating the PPARγ/HO-1. J. Cell. Biochem. 119: 392-400, 2018. © 2017 Wiley Periodicals, Inc.

Gambogenic Acid Exerts Antitumor Activity in Hypoxic Multiple Myeloma Cells by Regulation of miR-21

Hypoxia is an inseparable component of the bone marrow (BM) microenvironment, accounting for aggressive tumor behavior and poor prognosis of multiple myeloma (MM). Gambogenic acid (GNA) has proven to be an attractive option for treatment of tumors due to its tumor suppressive activity. Herein, we found that GNA exhibits remarkable apoptotic activity against MM cells even under hypoxia. MicroRNA-21 (miR-21) has been found over-expressed in MM patients and associated with the occurrence and development of MM. Direct studies have shown that there is a functional link between hypoxia and miR-21 expression in multiple types of tumors. In the current study, we found that hypoxia increased miR-21 expression in U266 cells and miR-21 induced by hypoxia was associated with concurrent reductions in its target PTEN. After treatment with GNA, miR-21 expression in hypoxic U266 cells was strikingly downregulated in a dose-dependent manner. Besides, we identified that regulation of miR-21/PTEN by GNA under hypoxia is related with inhibition of HIF-1α accumulation and STAT3 phosphorylation. Furthermore, in vivo study revealed that intravenous GNA injection could significantly suppress tumor growth and the miR-21/PTEN pathway is involved in GNA's anti-tumor effects. Taken together, all these results indicated that GNA could be a highly potent therapeutic for human MM.