MUC1 promotes lymph node metastasis in esophageal squamous cell carcinoma by downregulating DNAJB6 expression

BACKGROUND

Aberrant expression of MUC1 correlates with the progression of esophageal squamous cell carcinoma (ESCC), this study aimed to explore the effect of targeting MUC1 by Go-203 on malignant behavior of ESCC and the underlying mechanism.

METHODS AND RESULTS

IHC was used to examine the expression of MUC1 and DNAJB6 in ESCC samples. qRT-PCR and western blotting were used to examine the expression of MUC1 and DNAJB6 in ESCC cell lines. CCK8, wound healing, and transwell assays were used to determine the effect of regulating MUC1/DNAJB6 on the proliferation, migration, and invasion of ESCC cells. The effect of overexpressing/targeting MUC1 on the activation of the AKT/HSF-1 pathway was determined by western blotting. A negative correlation was confirmed between the expression of DNAJB6 and MUC1 in ESCC tissue samples by IHC, and high expression of MUC1 and low expression of DNAJB6 correlated with lymph node metastasis in ESCC patients. Overexpressing MUC1 downregulated the expression of DNAJB6, promoted ESCC proliferation, invasion, migration and activated the AKT pathway, while targeting MUC1 suppressed proliferation, invasion, migration, and the AKT pathway and up-regulated DNAJB6 expression in vitro. Moreover, MUC1 increased the phosphorylation of HSF-1 via the AKT pathway, and inhibiting AKT-HSF-1 increased the expression of DNAJB6 in vitro.

CONCLUSIONS

This study indicated that MUC1 could promote tumorigenesis and metastasis in ESCC by downregulating DNAJB6 expression through AKT-HSF-1 pathway.

Comparative modeling and mutual docking of structurally uncharacterized heat shock protein 70 and heat shock factor-1 proteins in water buffalo

Aim:

In this study, a wide range of in silico investigation of Bubalus bubalis (BB) heat shock protein 70 (HSP70) and heat shock factor-1 (HSF1) has been performed, ranging from sequence evaluation among species to homology modeling along with their docking studies to decipher the interacting residues of both molecules.

Materials and Methods:

Protein sequences of BB HSP70 and HSF1 were retrieved from NCBI database in FASTA format. Primary and secondary structure prediction were computed using Expasy ProtParam server and Phyre2 server, respectively. TMHMM server was used to identify the transmembrane regions in HSP70. Multiple sequence alignment and comparative analysis of the protein was carried out using MAFFT and visualization was created using ESPript 3.0. Phylogenetic analysis was accomplished by COBALT. Interactions of HSP70 with other proteins were studied using STRING database. Modeller 9.18, RaptorX, Swiss-Modeller, Phyre2, and I-TASSER were utilized to design the three-dimensional structure of these proteins followed by refinement; energy minimization was accomplished using ModRefiner and SPDBV program. Stereochemical quality along with the accuracy of the predicted models and their visualization was observed by PROCHECK program of PDBsum and UCSF Chimera, respectively. ClusPro 2.0 server was accessed for the docking of the receptor protein with the ligand.

Results:

The lower value of Grand Average of Hydropathy indicates the more hydrophilic nature of HSP70 protein. Value of the instability index (II) classified the protein as stable. No transmembrane region was reported for HSP70 by TMHMM server. Phylogenetic analysis based on multiple sequence alignments (MSAs) by COBALT indicated more evolutionarily closeness of Bos indicus (BI) with Bos taurus as compared to BI and BB. STRING database clearly indicates the HSF1 as one of the interacting molecules among 10 interacting partners with HSP 70. The best hit of 3D model of HSP70 protein and HSF1 was retrieved from I-TASSER and Phyre2, respectively. Interacting residues and type of bonding between both the molecules which were docked by ClusPro 2.0 were decoded by PIC server. Hydrophobic interactions, protein-protein main-chain-side-chain hydrogen bonds, and protein-protein side-chain-side-chain hydrogen bonds were delineated in this study.

Conclusion:

This is the first-ever study on in silico interaction of HSP70 and HSF1 proteins in BB. Several bioinformatics web tools were utilized to study secondary structure along with comparative modeling, physicochemical properties, and protein-protein interaction. The various interacting amino acid residues of both proteins have been indicated in this study.

Glutamine promotes Hsp70 and inhibits α-Synuclein accumulation in pheochromocytoma PC12 cells

Hsp70 regulates α-Synuclein (α-Syn) degeneration in Parkinson's disease (PD), indicating that Hsp70 promotion may be able to prevent or reverse α-Syn-induced toxicity in PD. Additionally, it has been demonstrated that glutamine (Gln) enhances Hsp70 expression. In the present study, Gln-induced Hsp70 promotion in pheochromocytoma was investigated with reverse transcription- quantitative polymerase chain reaction and western blotting methods. Then it was observed whether heat shock factor (HSF)-1 was required for this phenomenon with an RNA interference strategy. The regulatory role of Gln on α-Syn degeneration was also determined in the α-Syn-overexpressed PC12 [PC12 (α-Syn+)] cells, which were treated with or without the proteasomal inhibitor lactacystin (Lac). The results demonstrated that treatment with ≥10 mM Gln significantly increased Hsp70 mRNA and protein levels (P<0.05) and that this promotion was HSF-1-dependent, as HSF-1 knockout with HSF-1-specific small interfering RNA abrogated Hsp70 promotion in PC12 (α-Syn+) cells. Furthermore, Gln treatment markedly upregulated α-Syn degeneration in PC12 (α-Syn+) cells, which was significantly reduced (P<0.05) in the presence of Lac. Therefore, the present study suggests that Gln is able to induce the promotion of Hsp70 expression in PC12 cells in an HSF-1-dependent manner and that Gln-mediated Hsp70 promotion may increase α-Syn degradation even in the presence of proteasomal inhibitor. Thus, glutamine may be a potential therapeutic agent to prevent α-Syn aggregation in PD.

Exposure to febrile-range hyperthermia potentiates Wnt signalling and epithelial-mesenchymal transition gene expression in lung epithelium

BACKGROUND

As environmental and body temperatures vary, lung epithelial cells experience temperatures significantly different from normal core temperature. Our previous studies in human lung epithelium showed that: (i) heat shock accelerates wound healing and activates profibrotic gene expression through heat shock factor-1 (HSF1); (ii) HSF1 is activated at febrile temperatures (38-41 °C) and (iii) hypothermia (32 °C) activates and hyperthermia (39.5 °C) reduces expression of a subset of miRNAs that target protein kinase-Cα (PKCα) and enhance proliferation.

METHODS

We analysed the effect of hypo- and hyperthermia exposure on Wnt signalling by exposing human small airway epithelial cells (SAECs) and HEK293T cells to 32, 37 or 39.5 °C for 24 h, then analysing Wnt-3a-induced epithelial-mesenchymal transition (EMT) gene expression by qRT-PCR and TOPFlash reporter plasmid activity. Effects of miRNA mimics and inhibitors and the HSF1 inhibitor, KNK437, were evaluated.

RESULTS

Exposure to 39.5 °C for 24 h increased subsequent Wnt-3a-induced EMT gene expression in SAECs and Wnt-3a-induced TOPFlash activity in HEK293T cells. Increased Wnt responsiveness was associated with HSF1 activation and blocked by KNK437. Overexpressing temperature-responsive miRNA mimics reduced Wnt responsiveness in 39.5 °C-exposed HEK293T cells, but inhibitors of the same miRNAs failed to restore Wnt responsiveness in 32 °C-exposed HEK293T cells.

CONCLUSIONS

Wnt responsiveness, including expression of genes associated with EMT, increases after exposure to febrile-range temperature through an HSF1-dependent mechanism that is independent of previously identified temperature-dependent miRNAs. This process may be relevant to febrile fibrosing lung diseases, including the fibroproliferative phase of acute respiratory distress syndrome (ARDS) and exacerbations of idiopathic pulmonary fibrosis (IPF).

Activation of heat shock response augments fibroblast growth factor-1 expression in wounded lung epithelium

We previously showed that coincident exposure to heat shock (HS; 42°C for 2 h) and TNF-α synergistically induces apoptosis in mouse lung epithelium. We extended this work by analyzing HS effects on human lung epithelial responses to clinically relevant injury. Cotreatment with TNF-α and HS induced little caspase-3 and poly(ADP-ribose) polymerase cleavage in human small airway epithelial cells, A549 cells, and BEAS2B cells. Scratch wound closure rates almost doubled when A549 and BEAS2B cells and air-liquid interface cultures of human bronchial epithelial cells were heat shocked immediately after wounding. Microarray, qRT-PCR, and immunoblotting showed fibroblast growth factor 1 (FGF1) to be synergistically induced by HS and wounding. Enhanced FGF1 expression in HS/wounded A549 was blocked by inhibitors of p38 MAPK (SB203580) or HS factor (HSF)-1 (KNK-437) and in HSF1 knockout BEAS2B cells. PCR demonstrated FGF1 to be expressed from the two most distal promoters in wounded/HS cells. Wound closure in HS A549 and BEAS2B cells was reduced by FGF receptor-1/3 inhibition (SU-5402) or FGF1 depletion. Exogenous FGF1 accelerated A549 wound closure in the absence but not presence of HS. In the presence of exogenous FGF1, HS slowed wound closure, suggesting that it increases FGF1 expression but impairs FGF1-stimulated wound closure. Frozen sections from normal and idiopathic pulmonary fibrosis (IPF) lung were analyzed for FGF1 and HSP70 by immunofluorescence confocal microscopy and qRT-PCR. FGF1 and HSP70 mRNA levels were 7.5- and 5.9-fold higher in IPF than normal lung, and the proteins colocalized to fibroblastic foci in IPF lung. We conclude that HS signaling may have an important impact on gene expression contributing to lung injury, healing, and fibrosis.

Pro-inflammatory cytokines downregulate Hsp27 and cause apoptosis of human retinal capillary endothelial cells

The formation of acellular capillaries in the retina, a hallmark feature of diabetic retinopathy, is caused by apoptosis of endothelial cells and pericytes. The biochemical mechanism of such apoptosis remains unclear. Small heat shock proteins play an important role in the regulation of apoptosis. In the diabetic retina, pro-inflammatory cytokines are upregulated. In this study, we investigated the effects of pro-inflammatory cytokines on small heat shock protein 27 (Hsp27) in human retinal endothelial cells (HREC). In HREC cultured in the presence of cytokine mixtures (CM), a significant downregulation of Hsp27 at the protein and mRNA level occurred, with no effect on HSF-1, the transcription factor for Hsp27. The presence of high glucose (25mM) amplified the effects of cytokines on Hsp27. CM activated indoleamine 2,3-dioxygenase (IDO) and enhanced the production of kynurenine and ROS. An inhibitor of IDO, 1-methyl tryptophan (MT), inhibited the effects of CM on Hsp27. CM also upregulated NOS2 and, consequently, nitric oxide (NO). A NOS inhibitor, L-NAME, and a ROS scavenger blocked the CM-mediated Hsp27 downregulation. While a NO donor in the culture medium did not decrease the Hsp27 content, a peroxynitrite donor and exogenous peroxynitrite did. The cytokines and high glucose-induced apoptosis of HREC were inhibited by MT and L-NAME. Downregulation of Hsp27 by a siRNA treatment promoted apoptosis in HREC. Together, these data suggest that pro-inflammatory cytokines induce the formation of ROS and NO, which, through the formation of peroxynitrite, reduce the Hsp27 content and bring about apoptosis of retinal capillary endothelial cells.

Bicyclol: a novel antihepatitis drug with hepatic heat shock protein 27/70-inducing activity and cytoprotective effects in mice

Heat shock proteins (HSPs) are the best-known endogenous factors that protect against cell injury under various pathological conditions and that can be induced by various physical, chemical, and biological stressors. New research seeks to discover a compound that is clinically safe and can induce the accumulation of HSPs in patients. This paper reports that the oral administration of three doses of bicyclol, a novel antihepatitis drug, induced hepatic HSP27 and HSP70 expression in a time- and dose-dependent manner, and that bicyclol treatment stimulated heat shock factor 1 (HSF1) activation in mice. The inducing effects of bicyclol on HSP27, HSP70 and HSF1 were all blocked by quercetin, an inhibitor of HSP biosynthesis. The cytoprotective effect of HSP27/70 induced by bicyclol against hepatotoxicity of acetaminophen (AP) was assessed in mice. The prior administration of bicyclol markedly suppressed AP-induced liver injury as indicated by the reduction in the elevation of serum alanine aminotransferase and aspartate aminotransferase, in liver necrosis, in the release of cytochrome c and apoptosis-inducing factor from mitochondria, as well as in hepatic deoxyribonucleic acid fragmentation in mice. However, all the above actions of bicyclol against AP-induced mouse liver injuries were significantly attenuated by quercetin. This is the first report to show that bicyclol induces hepatic HSP27/70 expression via activation of HSF1 and that the cytoprotective action of bicyclol against liver injury is mediated by its induction of HSP27/70. These results provide new evidence for elucidating the mechanism of the hepatoprotective action of bicyclol in animals and patients.