Neuroinflammation Upregulated Neuronal Toll-Like Receptors 2 and 4 to Drive Synucleinopathy in Neurodegeneration.

Background: Parkinson's disease (PD) is characterized by intraneuronal α-synuclein aggregation called Lewy bodies and progressive dopaminergic neurodegeneration. Toll-like receptor (TLR) signaling is a major pathway mediating inflammation. The molecular link on how neuroinflammation upregulates neuronal TLRs and induces accumulation of α-synuclein aggregates to drive synucleinopathy remains to be determined. Objective: Despite conditioned medium from microglia and TLR agonists were utilized to study their effects on neuronal cells, a Transwell coculture system, comprising lipopolysaccharide-activated microglia on top and retinoic acid-differentiated SH-SY5Y cells at the bottom more mimicking in vivo neuroinflammation, was employed to elucidate the mechanism of activated microglia on neuronal cells. Methods: Genetic variants of TLRs in PD patients were genotyped and the multiplex cytokines, sRAGE, and HMGB1were assessed. A coculture system was employed to measure α-synuclein aggregates and neurite shortening by confocal microscope. The expression of TLR2/4 and autophagy flux was detected by western blot and immunofluorescence. Results: PD patients showed higher plasma levels of proinflammatory cytokines and genetic TLR4 variant, c.896 A > G (p. D299G). Elevated proinflammatory cytokines in coculture medium was also seen. Phosphorylation and aggregation of α-synuclein, shortening of neurite, upregulation of TLR2/4 expression, activation of downstream p38 and JNK, and dampening of autophagic flux were seen in SH-SY5Y cells cocultured with activated microglia. Those were prevented by inhibiting TLR2/4 and p38/JNK signaling. Conclusion: Activated microglia-derived neuroinflammation induced neuronal TLR2/4-p38/JNK activation to perturb autophagy, causing accumulation of α-synuclein aggregates and neurite shortening. Targeting neuronal TLR2/4 pathway might be a mechanistic-based therapy for neurodegenerative disease, such as PD.

A dual inhibitor targeting HMG-CoA reductase and histone deacetylase mitigates neurite degeneration in LRRK2-G2019S parkinsonism.

Parkinson's disease (PD) is among the most common neurodegenerative disorders, and its etiology involves both genetic and environmental factors. The leucine-rich repeat kinase (LRRK2) G2019S mutation is the most common genetic cause of familial and sporadic PD. Current treatment is limited to dopaminergic supplementation, as no disease-modifying therapy is available yet. Recent evidence reveals that HMG-CoA reductase (HMGR) inhibitors (statins) exert neuroprotection through anti-neuroinflammatory effects, and histone deacetylase (HDAC) inhibitors mitigate neurodegeneration by promoting the transcription of neuronal survival factors. We designed and synthesized a dual inhibitor, statin hydroxamate JMF3086, that simultaneously inhibits HMGR and HDAC, and examined its neuroprotective effects on LRRK2-G2019S parkinsonism. JMF3086 restored dopaminergic neuron loss in aged LRRK2-G2019S flies and rescued neurite degeneration in primary hippocampal and dopaminergic neurons isolated from transgenic LRRK2-G2019S mice. The molecular mechanisms included downregulation of ERK1/2 phosphorylation, increased anti-apoptotic Akt phosphorylation, and inhibition of GSK3ß activity to maintain cytoskeletal stability in stably transfected LRRK2-G2019S SH-SY5Y human dopaminergic cells. JMF3086 also promoted a-tubulin acetylation and kinesin-1 expression, facilitating antegrade mitochondrial transport in axons. Our findings demonstrate that JMF3086 exerted beneficial effects on restoring LRRK2-G2019S neurite degeneration by maintaining microtubule stability. This dual-target compound may be a promising mechanism-based therapy for PD.

Metabolic targeting of HIF-1α potentiates the therapeutic efficacy of oxaliplatin in colorectal cancer.

Drug resistance is a major problem limiting the efficacy of chemotherapy in cancer treatment, and the hypoxia-induced stabilization of HIF-1α plays a role in this process. HIF-1α overexpression has been observed in a variety of human cancers, including colorectal cancer (CRC). Therefore, targeting HIF-1α is a promising strategy for overcoming chemoresistance to enhance the efficacy of chemotherapies in CRC. Here, we show that DNMT inhibitors can induce HIF-1α degradation to overcome oxaliplatin resistance and enhance anti-CRC therapy. We found that a low-toxicity DNMT inhibitor, zebularine, could downregulate HIF-1α expression and overcome hypoxia-induced oxaliplatin resistance in HCT116 cells and showed efficacy in HCT116 xenograft models and AOM/DSS-induced CRC mouse models. Zebularine could induce the degradation of HIF-1α protein through hydroxylation. LC-MS analysis showed a decrease in succinate in various CRC cells under hypoxia and in colon tissues of AOM/DSS-induced CRC mice. The decrease was reversed by zebularine. Tumor angiogenesis was also reduced by zebularine. Furthermore, zebularine potentiated the anticancer effect of oxaliplatin in AOM/DSS-induced CRC models. This finding provides a new strategy in which an increase in HIF-1α hydroxylation could overcome oxaliplatin resistance to enhance anti-CRC therapy.

Correction: Metformin sensitizes anticancer effect of dasatinib in head and neck squamous cell carcinoma cells through AMPK-dependent ER stress.

[This corrects the article DOI: 10.18632/oncotarget.1628.].

Correction: Metformin sensitizes anticancer effect of dasatinib in head and neck squamous cell carcinoma cells through AMPK-dependent ER stress.

[This corrects the article DOI: 10.18632/oncotarget.1628.].

Epithelial-mesenchymal transition (EMT) beyond EGFR mutations per se is a common mechanism for acquired resistance to EGFR TKI.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) is a major advance in treating NSCLC with EGFR-activating mutations. However, acquired resistance, due partially to secondary mutations limits their use. Here we report that NSCLC cells with acquired resistance to gefitinib or osimertinib (AZD9291) exhibit EMT features, with a decrease in E-cadherin, and increases in vimentin and stemness, without possessing any EGFR secondary mutations. Knockdown of E-cadherin in parental cells increased gefitinib resistance and stemness, while knockdown of vimentin in resistant cells resulted in opposite effects. Src activation and Hakai upregulation were found in gefitinib-resistant cells. Knockdown of Hakai elevated E-cadherin expression, attenuated stemness, and resensitized the cells to gefitinib. Clinical cancer specimens with acquired gefitinib resistance also showed a decrease in E-cadherin and an increase in Hakai expression. The dual HDAC and HMGR inhibitor JMF3086 inhibited the Src/Hakai and Hakai/E-cadherin interaction to reverse E-cadherin expression, and attenuated vimentin and stemness to restore gefitinib sensitivity. The EMT features of AZD9291-resistant H1975 cells were related to the upregulation of Zeb1. Both gefitinib and AZD9291 sensitivity was restored by JMF3086 through reversing EMT. Our study not only revealed a common mechanism of EMT in both gefitinib and AZD9291 resistance beyond EGFR mutations per se, but also provides a new strategy to overcome it.

Prevention of Colitis and Colitis-Associated Colorectal Cancer by a Novel Polypharmacological Histone Deacetylase Inhibitor.

PURPOSE: Colorectal cancer is a worldwide cancer with rising annual incidence. Inflammation is a well-known cause of colorectal cancer carcinogenesis. Metabolic inflammation (metaflammation) and altered gut microbiota (dysbiosis) have contributed to colorectal cancer. Chemoprevention is an important strategy to reduce cancer-related mortality. Recently, various polypharmacologic molecules that dually inhibit histone deacetylases (HDAC) and other therapeutic targets have been developed. EXPERIMENTAL DESIGN: Prevention for colitis was examined by dextran sodium sulfate (DSS) mouse models. Prevention for colorectal cancer was examined by azoxymethane/dextran sodium sulfate (AOM/DSS) mouse models. Immunohistochemical staining was utilized to analyze the infiltration of macrophages and neutrophils and COX-II expression in mouse tissue specimens. The endotoxin activity was evaluated by Endotoxin Activity Assay Kit. RESULTS: We synthesized a statin hydroxamate that simultaneously inhibited HDAC and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR). Its preventive effect on colitis and colitis-associated colorectal cancer in mouse models was examined. Oral administration of this statin hydroxamate could prevent acute inflammation in the DSS-induced colitis and AOM/DSS-induced colorectal cancer with superior activity than the combination of lovastatin and SAHA. It also reduced proinflammatory cytokines, chemokines, expression of COX-II, and cyclin D1 in inflammation and tumor tissues, as well as decreasing the infiltration of macrophages and neutrophils in tumor-surrounding regions. Stemness of colorectal cancer and the release of endotoxin in AOM/DSS mouse models were also attenuated by this small molecule. CONCLUSIONS: This study demonstrates that the polypharmacological HDAC inhibitor has promising effect on the chemoprevention of colorectal cancer, and serum endotoxin level might serve as a potential biomarker for its chemoprevention. Clin Cancer Res; 22(16); 4158-69. ©2016 AACR.

Nuclear IKKα mediates microRNA-7/-103/107/21 inductions to downregulate maspin expression in response to HBx overexpression.

Maspin is a tumor suppressor that stimulates apoptosis and inhibits metastasis in various cancer types, including hepatocellular carcinoma (HCC). Our previous study has demonstrated that HBx induced microRNA-7, 103, 107, and 21 expressions to suppress maspin expression, leading to metastasis, chemoresistance, and poor prognosis in HCC patients. However, it remains unclear how HBx elicits these microRNA expressions. HBx has been known to induce aberrant activation and nuclear translocation of inhibitor-κB kinase-α (IKKα) to promote HCC progression. In this study, our data further revealed that nuclear IKKα expression was inversely correlated with maspin expression in HBV-associated patients. Nuclear IKKα but not IKKß reduced maspin protein and mRNA expression, and inhibition of IKKα reverses HBx-mediated maspin downregulation and chemoresistance. In response to HBx overexpression, nuclear IKKα was further demonstrated to induce the gene expressions of microRNA-7, -103, -107, and -21 by directly targeting their promoters, thereby leading to maspin downregulation. These findings indicated nuclear IKKα as a critical regulator for HBx-mediated microRNA induction and maspin suppression, and suggest IKKα as a promising target to improve the therapeutic outcome of HCC patients.

Dual Targeting of 3-Hydroxy-3-methylglutaryl Coenzyme A Reductase and Histone Deacetylase as a Therapy for Colorectal Cancer.

Statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (HMGR) inhibitors decreasing serum cholesterol and have shown promise in cancer prevention. In this study, we demonstrated the oncogenic role of HMGR in colorectal cancer (CRC) by disclosing increased HMGR activity in CRC patients and its enhancement of anti-apoptosis and stemness. Our previous studies showed that statins containing carboxylic acid chains possessed activity against histone deacetylases (HDACs), and strengthened their anti-HDAC activity through designing HMGR-HDAC dual inhibitors, JMF compounds. These compounds exerted anti-cancer effect in CRC cells as well as in AOM-DSS and Apc(Min/+) CRC mouse models. JMF mostly regulated the genes related to apoptosis and inflammation through genome-wide ChIP-on-chip analysis, and Ingenuity Pathways Analysis (IPA) predicted their respective regulation by NR3C1 and NF-κB. Furthermore, JMF inhibited metastasis, angiogenesis and cancer stemness, and potentiated the effect of oxaliplatin in CRC mouse models. Dual HMGR-HDAC inhibitor could be a potential treatment for CRC.

miRNA-7/21/107 contribute to HBx-induced hepatocellular carcinoma progression through suppression of maspin.

Maspin suppresses tumor progression by promoting cell adhesion and apoptosis and by inhibiting cell motility. However, its role in tumorigenesis of hepatocellular carcinoma (HCC) remains unclear. The gene regulation of maspin and its relationship with HCC patient prognosis were investigated in this study. Maspin expression was specifically reduced in HBV-associated patients and correlated with their poor prognosis. Maspin downregulation in HCC cells was induced by HBx to promote their motility and resistance to anoikis and chemotherapy. HBx-dependent induction of microRNA-7, -107, and -21 was further demonstrated to directly target maspin mRNA, leading to its protein downregulation. Higher expressions of these microRNAs also correlated with maspin downregulation in HBV-associated patients, and were associated with their poor overall survival. These data not only provided new insights into the molecular mechanisms of maspin deficiency by HBx, but also indicated that downregulation of maspin by microRNAs confers HBx-mediated aggressiveness and chemoresistance in HCC.

Induction of c-Cbl contributes to anti-cancer effects of HDAC inhibitor in lung cancer.

Here we found loss of c-Cbl, an E3 ligase, expression in non-small cell lung cancer (NSCLC) compared with its adjacent normal tissue in patient specimens. HDAC inhibition by WJ or knockdown of HDAC 1, HDAC2, HDAC3 or HDAC6 all induced c-Cbl. Ectopic expression of c-Cbl induced decreased EGFR, inhibited growth in NSCLC cells. Knockdown of EGFR inhibited NSCLC growth. Mutation of EGFR at Y1045 decreased WJ-induced growth inhibition as well as in vivo anti-cancer effect and EGFR degradation mediated by WJ. Time-lapse confocal analysis showed co-localization of c-Cbl and EGFR after WJ treatment. Furthermore, WJ inhibited lung tumor growth through c-Cbl induction in orthotopic and tail vein injected models. C-Cbl up-regulation induced by HDACi is a potential strategy for NSCLC treatment.

DUSP1 expression induced by HDAC1 inhibition mediates gefitinib sensitivity in non-small cell lung cancers.

PURPOSE: Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related death worldwide. Patients with NSCLC with EGFR-activating mutation benefit greatly by gefitinib, an EGFR tyrosine kinase inhibitor. However, acquired resistance limits its clinical use. Histone deacetylases (HDAC) are oncoproteins associated with cancer progression and drug resistance. Here, we disclosed that inhibition of HDAC1 induced protein phosphatase DUSP1 upregulation to overcome gefitinib-acquired resistance. EXPERIMENTAL DESIGN: The effect of HDAC1 inhibition restored gefitinib sensitivity was assessed by in vitro MTT and apoptotic assays, and in vivo xenograft and orthotopic lung cancer mouse models. Protein phosphatase array was used to detect DUSP1 expression. Immunohistochemical staining and quantitative PCR were used to analyze DUSP1 expression in clinical NSCLC specimens. RESULTS: Gefitinib-resistant NSCLC cells showed HDAC1 overexpression, and its knockdown sensitized resistant cells to gefitinib in vitro and in preclinical models through DUSP1 expression. Overexpression of DUSP1 in resistant cells restored gefitinib sensitivity by inhibiting EGFR signaling and inducing apoptosis, whereas its knockdown in sensitive cells conferred gefitinib resistance. A novel HDAC inhibitor, WJ-26210-2, in combination with gefitinib upregulated DUSP1 expression to exert in vitro and in vivo synergistic effect on inactivation of EGFR signaling, growth inhibition, and apoptosis. Clinically, high DUSP1 level was correlated with delayed emergence of gefitinib-acquired resistance. CONCLUSIONS: Decreased DUSP1 might be a mechanism responsible for gefitinib resistance, and DUSP1 might be a biomarker for gefitinib efficacy. HDAC1 inhibition-induced DUSP1 upregulation could be a promising strategy to overcome gefitinib-acquired resistance. Clin Cancer Res; 21(2); 428-38. ©2015 AACR.

AID downregulation is a novel function of the DNMT inhibitor 5-aza-deoxycytidine.

Activation-induced cytidine deaminase (AID) was originally identified as an inducer of somatic hypermutation (SHM) and class switch recombination (CSR) in immunoglobulin genes. However, AID can also cause mutations in host genes and contribute to cancer progression and drug resistance. In this study, molecular docking showed the interaction of free 5-aza-CdR and Zebularine (Zeb) with AID. However, only 5-aza-CdR-incorporated ssDNA bound to the active site of AID and inhibited AID expression through proteasomal degradation. 5-aza-CdR demonstrated cytotoxicity against AID-positive and -negative hematopoietic cancer cells. In contrast, Zeb exhibited a cytotoxic effect only in AID-negative cells due to its inability to inhibit AID expression. This differential effect might be due to the DNMT1 stabilization induced by AID, thus restricting the ability of Zeb to deplete DNMT1 and induce tumor suppressor genes (TSGs), such as p21, in AID-positive cells. Moreover, the in vivo anticancer effect of 5-aza-CdR but not Zeb in AID-positive hematopoietic cancer cells was demonstrated. The study not only displays the association of AID and DNMT1 and identifies a novel biological function of AID, but also provides novel information regarding the use of DNMT inhibitors to treat AID-positive hematopoietic cancers.

Metformin sensitizes anticancer effect of dasatinib in head and neck squamous cell carcinoma cells through AMPK-dependent ER stress.

Head and neck squamous cell carcinoma (HNSCC) is an important endemic disease in Taiwan with aggressive course and dismal outcome. Dasatinib is a Bcr-bl and Src kinase inhibitor that has potential against HNSCC. We recently disclosed that EGFR degradation is critical for dasatinib-induced apoptosis. Here, we further demonstrate that AMPK-dependent ER stress is responsible for this event. Dasatinib induced ER stress which mediated EGFR degradation in a c-cbl-dependent manner. AMPK activation induced by dasatinib might be due to ATP decrease through the up-regulation of pyruvate dehydrogenase kinase 4 (PDK4). Furthermore, activation of AMPK by metformin sensitized dasatinib-induced in vitro and in vivo anti-cancer effect. The correlation of AMPK activation and EGFR expression was seen in HNSCC cells and human tumor specimens. Our results disclose that AMPK-dependent ER stress plays a crucial role in the anti-cancer effect of dasatinib in HNSCC and further activation of AMPK by metformin might enhance dasatinib efficacy.

Zebularine inhibits tumorigenesis and stemness of colorectal cancer via p53-dependent endoplasmic reticulum stress.

Aberrant DNA hypermethylation is frequently found in tumor cells and inhibition of DNA methylation is an effective anticancer strategy. In this study, the therapeutic effect of DNA methyltransferase (DNMT) inhibitor zebularine (Zeb) on colorectal cancer (CRC) was investigated. Zeb exhibited anticancer activity in cell cultures, tumor xenografts and mouse colitis-associated CRC model. It stabilizes p53 through ribosomal protein S7 (RPS7)/MDM2 pathways and DNA damage. Zeb-induced cell death was dependent on p53. Microarray analysis revealed that genes related to endoplasmic reticulum (ER) stress and unfolded protein response (UPR) were affected by Zeb. Zeb induced p53-dependent ER stress and autophagy. Pro-survival markers of ER stress/UPR (GRP78) and autophagy (p62) were increased in tumor tissues of CRC patients, AOM/DSS-induced CRC mice and HCT116-derived colonospheres. Zeb downregulates GRP78 and p62, and upregulates a pro-apoptotic CHOP. Our results reveal a novel mechanism for the anticancer activity of Zeb.

Design and synthesis of dual-action inhibitors targeting histone deacetylases and 3-hydroxy-3-methylglutaryl coenzyme A reductase for cancer treatment.

A series of dual-action compounds were designed to target histone deacetylase (HDAC) and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) by having a hydroxamate group essential for chelation with the zinc ion in the active site of HDAC and the key structural elements of statin for binding with both proteins. In our study, the statin hydroxamic acids prepared by a fused strategy are most promising in cancer treatments. These compounds showed potent inhibitory activities against HDACs and HMGR with IC50 values in the nanomolar range. These compounds also effectively reduced the HMGR activity as well as promoted the acetylations of histone and tubulin in cancer cells, but were not toxic to normal cells.

Degradation of epidermal growth factor receptor mediates dasatinib-induced apoptosis in head and neck squamous cell carcinoma cells.

Epidermal growth factor receptor (EGFR) is an important oncoprotein that promotes cell growth and proliferation. Dasatinib, a bcr-abl inhibitor, has been approved clinically for the treatment of chronic myeloid leukemia and demonstrated to be effective against solid tumors in vitro through Src inhibition. Here, we disclose that EGFR degradation mediated dasatinib-induced apoptosis in head and neck squamous cell carcinoma (HNSCC) cells. HNSCC cells, including Ca9-22, FaDu, HSC3, SAS, SCC-25, and UMSCC1, were treated with dasatinib, and cell viability, apoptosis, and underlying signal transduction were evaluated. Dasatinib exhibited differential sensitivities against HNSCC cells. Growth inhibition and apoptosis were correlated with its inhibition on Akt, Erk, and Bcl-2, irrespective of Src inhibition. Accordingly, we found that down-regulation of EGFR was a determinant of dasatinib sensitivity. Lysosome inhibitor reversed dasatinib-induced EGFR down-regulation, and c-cbl activity was increased by dasatinib, indicating that dasatinib-induced EGFR down-regulation might be through c-cbl-mediated lysosome degradation. Increased EGFR activation by ligand administration rescued cells from dasatinib-induced apoptosis, whereas inhibition of EGFR enhanced its apoptotic effect. Estrogen receptor α (ERα) was demonstrated to play a role in Bcl-2 expression, and dasatinib inhibited ERα at the pretranslational level. ERα was associated with EGFR in dasatinib-treated HNSCC cells. Furthermore, the xenograft model showed that dasatinib inhibited HSC3 tumor growth through in vivo down-regulation of EGFR and ERα. In conclusion, degradation of EGFR is a novel mechanism responsible for dasatinib-induced apoptosis in HNSCC cells.

CD1d induction in solid tumor cells by histone deacetylase inhibitors through inhibition of HDAC1/2 and activation of Sp1.

CD1d is a MHC class-like molecule that presents glycolipids to natural killer T (NKT) cells, then regulates innate and adaptive immunity. The regulation of CD1d gene expression in solid tumors is still largely unknown. Gene expression can be epigenetically regulated by DNA methylation and histone acetylation. We found that histone deacetylase inhibitors, trichostatin A (TSA) and suberoylanilide hydroxamic acid (SAHA), induced CD1d gene expression in human (A549 and NCI-H292) and mouse (TC-1 and B16/F0) cancer cells. Simultaneous knockdown of HDAC1 and 2 induced CD1d gene expression. Sp1 inhibitor mitramycin A (MTM) blocked TSA- and SAHA-induced CD1d mRNA expression and Sp1 luciferase activity. Co-transfection of GAL4-Sp1 and Fc-luciferase reporters demonstrated that TSA and SAHA induced Sp1 luciferase reporter activity by enhancing Sp1 transactivation activity. The binding of Sp1 to CD1d promoter and histone H3 acetylation on Sp1 sites were increased by TSA and SAHA. These results indicate that TSA and SAHA could up-regulate CD1d expression in tumor cells through inhibition of HDAC1/2 and activation of Sp1.

CIP2A-mediated Akt activation plays a role in bortezomib-induced apoptosis in head and neck squamous cell carcinoma cells.

Head and neck squamous cell carcinoma (HNSCC) is a worldwide disease with aggressive course and dismal outcome. Bortezomib, a proteasome inhibitor, has been approved clinically for hematological malignancies and demonstrated to have activities against solid tumors in vitro through inhibition of NF-kB activity. Here, we disclose that bortezomib induced apoptosis of HNSCC cells in vitro and in vivo through inhibition of cancerous inhibitor of protein phosphatase 2A (CIP2A)-mediated PP2A dependent Akt activation. HNSCC cells, including Ca9-22, SAS, and SCC-25, were treated with bortezomib and evaluated for viability, apoptosis, and signal transduction. Three HNSCC cells, including Ca9-22, SAS, and SCC-25, were sensitive to bortezomib with marked growth inhibition and apoptosis. We found phospho-Akt (p-Akt, Ser473) played a significant role in bortezomib-induced apoptosis. The activity of PP2A was significantly increased after the treatment of bortezomib without alternation of PP2A level or the dynamic interaction of PP2A-Akt. Silencing PP2A by small interference RNA (siRNA) abolished bortezomib-induced Akt inhibition and apoptosis. In addition, bortezomib inhibited CIP2A in pre-translational level in a dose- and time-dependent manner. Over-expression of CIP2A up-regulated p-Akt and protected HNSCC cells from bortezomib-induced apoptosis. Furthermore, xenograft model showed that bortezomib down-regulated CIP2A and p-Akt in SAS tumor cells. CIP2A is demonstrated to be a new therapeutic target of bortezomib in HNSCC.