Differential expression of a novel gene in response to hsp27 and cell differentiation in human keratinocytes

Discovery of Novel HSP27 Inhibitors as Prospective Anti-Cancer Agents Utilizing Computer-Assisted Therapeutic Discovery Approaches

Heat shock protein 27 (HSP27) is a protein that works as a chaperone and an antioxidant and is activated by heat shock, environmental stress, and pathophysiological stress. However, HSP27 dysregulation is a characteristic of many human cancers. HSP27 suppresses apoptosis and cytoskeletal reorganization. As a result, it is recognized as a critical therapeutic target for effective cancer therapy. Despite the effectiveness of multiple HSP27 inhibitors in pre-clinical investigations and clinical trials, no HSP27 inhibitor has progressed to the anticancer phase of the development. These difficulties have mostly been attributable to existing anticancer therapies’ inability to target oncogenic HSP27. Highly selective HSP27 inhibitors with higher effective-ness and low toxicity led to the development of combination techniques that include computer-aided assisted therapeutic discovery and design. This study emphasizes the most recent results and roles of HSP27 in cancer and the potential for utilizing an anticancer chemical database to uncover novel compounds to inhibit HSP27.

MgCl2 promotes mouse mesenchymal stem cell osteogenic differentiation by activating the p38/Osx/Runx2 signaling pathway

Magnesium, an important inorganic mineral component in bones, enhances osteoblast adhesion and osteogenic gene expression. Mg2+‑containing hydroxyapatite promotes mouse mesenchymal stem cell (MMSC) osteogenic differentiation. In the present study, MMSCs were cultured in media containing different concentrations of MgCl2 (0 and 20 mM) for different time periods. Western blotting and reverse transcription‑quantitative PCR were performed to determine the expression levels of phosphorylated (p)‑p38 mitogen‑activated protein kinase (MAPK), the osteoblast‑specific transcription factor Osterix (Osx), runt‑related transcription factor 2 (Runx2), and p38 downstream genes, such as 27 kDa heat shock protein (hsp27), activating transcription factor 4 (Atf4), myocyte enhancer factor 2C (Mef2c) and CCAAT/enhancer‑binding protein homologous protein (Ddit3). The facilitatory effect of MgCl2 on MMSC osteogenic differentiation was assessed via Alizarin Red staining. The results suggested that MgCl2 increased p38 phosphorylation compared with the control group. Downstream genes of the p38 signaling pathway, including Osx and Runx2, as well as several osteogenesis‑associated downstream target genes, including Hsp27, Atf4, Ddit3 and Mef2c, were significantly upregulated in the Mg2+‑treated group compared with the control group. The increased osteogenic differentiation in the Mg2+‑treated group was significantly attenuated in MMSCs treated with SB203580, a specific inhibitor of the p38 signaling pathway. The results suggested that appropriate concentrations of MgCl2 promoted MMSC osteogenic differentiation via regulation of the p38/Osx/Runx2 signaling pathway.

Targeting Heat Shock Protein 27 in Cancer: A Druggable Target for Cancer Treatment?

Heat shock protein 27 (HSP27), induced by heat shock, environmental, and pathophysiological stressors, is a multi-functional protein that acts as a protein chaperone and an antioxidant. HSP27 plays a significant role in the inhibition of apoptosis and actin cytoskeletal remodeling. HSP27 is upregulated in many cancers and is associated with a poor prognosis, as well as treatment resistance, whereby cells are protected from therapeutic agents that normally induce apoptosis. This review highlights the most recent findings and role of HSP27 in cancer, as well as the strategies for using HSP27 inhibitors for therapeutic purposes.

Hsp27 and Hsp70 Expression in Esophageal Squamous

Twenty-eight specimens of Esophael squamous cell carcinoma (ESCC) were obtained by surgery procedures.The tissues were fixed in formalin and embedded in paraffin. In each case, all available hematoxylin and eosin stained sections were examined and a representative block was selected. The ages of these patients ranged from 40 to 93 years, with a mean age of 60 years. Results. The histological grade of tumors was 4 well-differentiated, 19 moderately differentiated and 5 poorly differentiated. Expression of Hsp27 and Hsp70 in ESCC was demonstrated in 23 (82,14%) and 26 (92,86%) cases, respectively. Adjacent normal mucosa was positive in 11 (39,29%) samples and 9 (32,15%) samples for Hsp27 and Hsp70, respectively. No relationship between the expression of Hsp27 and Hsp70 with the clinicopathological parameters, including gender, age, surgical margin, lymph node status and tumor differentiation. The median follow-up period was 60 months. Survival analysis of patients with ESCC showed no relationship with the expression of Hsp27 and Hsp70. Conclusion. Taken together, our results demonstrate that Hsp27 and Hsp70 are expressed in ESCC tissues, but they are not good prognostic factor for patients with ESCC.

Localization of heat shock protein 27 (hsp27) in the rat gingiva and its changes with tooth eruption

Heat shock protein 27 kDa (Hsp27) functions as a molecular chaperon to prevent apoptosis as well as to contribute to the regulation of cell proliferation and differentiation during development. In the present study, the localization of Hsp27 in the oral epithelium of rats and its expression change during formation of the gingiva with the tooth eruption were examined immunohistochemically to elucidate the roles of Hsp27 in the oral mucosa.

In adult rats, Hsp27-immunoreactivity was localized in the prickle and granular layers but absent in the basal and horny layers of the oral epithelium. On the other hand, in the outer and sulcular epithelia of the free gingival, Hsp27-immunoreactivity was detected in the whole layers, while it was not found in the proliferation zone of the junctional epithelium immunoreactive for Ki67. In immature rats on 10th postnatal day, Hsp27-immunoreactivity was intense in the prickle and granular layers of the oral epithelium, but was not detected in its basal layer. In rats at the eruptive phase on 15th postnatal day, Hsp27-immunoreactivity was detected in sites of the basal layer adjacent to where the dental cusps penetrated through the oral epithelium. Although the immunoreactivity for Ki67 was found in the basal layer of the oral epithelium, it was not localized in the Hsp27-immunopositive sites of tooth-penetration in the basal layer. Just after the tooth-eruption on 20th postnatal day, Hsp27-immunoreactivity was not found in the stratified squamous epithelium at the dentogingival junction, whereas it was intense in a single layer of cuboidal epithelial cells attached to the tooth neck. Ki67-positive cells were scattered in the stratified squamous epithelium at the dentogingival junction, whereas no positive cells were found in the portion of a single layer of cuboidal epithelial cells.

These findings suggest that the outer and sulcular epithelia of the free gingiva have a relatively slower rate of proliferation than other gingival and oral epithelia, and that Hsp27 might inhibit the proliferation of the basal cells. Such specific phenomenon in the free gingiva occurred immediately after the dental cusps were exposed to the oral cavity.

Heat shock proteins in animal neoplasms and human tumours--a comparison

Heat shock proteins (HSPs) are implicated in all phases of cancer from proliferation, impaired apoptosis and sustained angiogenesis to invasion and metastasis. The presence of abnormal HSP levels in several human tumours suggests that these proteins could be used as diagnostic and/or prognostic markers, whilst the direct correlation between HSP expression and drug resistance in neoplastic tissues means they could also be used to predict cancer response to specific treatment. HSPs have also been successfully targeted in clinical trials modifying their expression or chaperone activity. Preliminary studies in veterinary medicine have also demonstrated the presence of altered HSP expression in neoplasms, and the study of carcinogenesis and the role of HSPs in animal models will surely be an additional source of information for clinical cancer research.

Heat shock protein expression in canine malignant mammary tumours

Background

Abnormal levels of Heat Shock Proteins (HSPs) have been observed in many human neoplasms including breast cancer and it has been demonstrated that they have both prognostic and therapeutic implications. In this study, we evaluated immunohistochemical expression of HSPs in normal and neoplastic canine mammary glands and confronted these results with overall survival (OS), in order to understand the role of HSPs in carcinogenesis and to establish their potential prognostic and/or therapeutic value.

Methods

Immunohistochemical expression of Hsp27, Hsp72, Hsp73 and Hsp90 was evaluated in 3 normal canine mammary glands and 30 malignant mammary tumours (10 in situ carcinomas, 10 invasive carcinomas limited to local structures without identifiable invasion of blood or lymphatic vessels, 10 carcinomas with invasion of blood or lymphatic vessels and/or metastases to regional lymph nodes). A semi-quantitative method was used for the analysis of the results.

Results

Widespread constitutive expression of Hsp73 and Hsp90 was detected in normal tissue, Hsp72 appeared to be focally distributed and Hsp27 showed a negative to rare weak immunostaining. In mammary tumours, a significant increase in Hsp27 (P < 0.01), Hsp72 (P < 0.05) and Hsp90 (P < 0.01) expression was observed as well as a significant reduction in Hsp73 (P < 0.01) immunoreactivity compared to normal mammary gland tissue. Hsp27 demonstrated a strong positivity in infiltrating tumour cells and metaplastic squamous elements of invasive groups. High Hsp27 expression also appeared to be significantly correlated to a shorter OS (P = 0.00087). Intense immunolabelling of Hsp72 and Hsp73 was frequently detected in infiltrative or inflammatory tumour areas. Hsp90 expression was high in all tumours and, like Hsp73, it also showed an intense positivity in lymphatic emboli.

Conclusion

These results suggest that Hsp27, Hsp72 and Hsp90 are involved in canine mammary gland carcinogenesis. In addition, Hsp27 appears to be implicated in tumour invasiveness and its high immunodetection in invasive tumours is indicative of a poorer clinical outcome.

Hsp27 Expression Coincides with Epidermal Stratification during Human Epidermal Morphogenesis

Heat shock protein 27 (Hsp27), apart from its protective function in response to stress, is implicated in the regulation of cell growth, differentiation and apoptosis. Data on the expression of Hsp27 in the developing human epidermis are sparse and partially conflicting. Thus, the purpose of the present study was to investigate Hsp27 expression during the morphogenesis of human epidermis. Skin biopsies and dispase-separated epidermal sheets obtained from 7 human embryos (7 and 8 weeks estimated gestational age, EGA), from 79 human fetuses (9-23 weeks EGA) and from 10 healthy adult volunteers were investigated by immunohistochemistry and Western blotting, respectively. The earliest detection of Hsp27 expression was found by immunohistochemistry at the 12th week EGA (basal and intermediate layer) and by Western blotting at the 9th week EGA. From the 16th to the 23rd week EGA immunoreactivity was not detectable in the basal layer, whereas in the overlying layers it revealed a differentiation-related pattern. The simultaneous onset of epidermal stratification and Hsp27 expression (9th week EGA) and the alterations of the latter in the subsequent stages of development, suggest that this stress protein may be involved in the molecular events underlying human epidermal morphogenesis.

Heat shock proteins expression in canine intracutaneous cornifying epithelioma and squamous cell carcinoma

Heat shock proteins (HSPs) are strongly implicated in the control of cell growth, differentiation and biological behaviour of many human cutaneous neoplasms. To our knowledge, no data have been published in the veterinary literature concerning either normal or neoplastic skin. In this study, the immunohistochemical expression of Hsp27, Hsp72 and Hsp73 was evaluated in normal canine skin, 14 intracutaneous cornifying epitheliomas (ICE), 10 well-differentiated and 5 moderately differentiated squamous cell carcinomas (SCC). Expression was correlated with the histological degree of keratinocyte differentiation and proliferation, and investigated as to its usefulness in the differential diagnosis of these canine tumours. In normal epidermis, Hsp27 exhibited cytoplasmic labelling in the spinous and granular layers, whereas in neoplastic tissues it was detected particularly in those areas showing squamous differentiation. Hsp72 immunoreactivity was more intense in ICE and well-differentiated SCC than in normal skin; however, reduced immunolabelling was observed in moderately differentiated SCC. Unlike Hsp72, Hsp73 showed less intense labelling in ICE and well-differentiated SCC than in normal epithelium and an increased positivity in moderately differentiated SCC. These results indicate that HSP immunoreactivity differs between normal and neoplastic canine skin. Hsp27 expression seems to correlate directly with cellular differentiation; by contrast, the involvement of Hsp72/73 in proliferation and differentiation of tumour cells remains controversial. The pattern and intensity of immunolabelling of each investigated HSP did not show, however, significant differences between ICE and SCC; therefore, they do not seem to be useful in the differential diagnosis of these two canine tumours.

Heat Shock Proteins (HSPs) 27, 72 and 73 in Normal and Pre-ulcerative Mucosa of the Gastric Pars Oesophagea in Swine

Heat shock proteins (HSPs), known to play a key role in cellular homeostasis, may also play a role in the defensive mechanisms of gastric mucosa. By means of appropriate immunohistochemical and immunobiochemical techniques, the expression of HSP27, HSP72 and HSP73 within the epithelium of normal and pre-ulcerative (hyperkeratinized) mucosa of the pars oesophagea of abattoir pigs was assessed. In normal mucosa, HSP72 and HSP73 expression was mainly limited to the basal epithelial cell layer, whereas HSP27 expression was consistently detected within the superficial epithelial cell layers. In hyperkeratinized mucosa, HSP72 and HSP73 immunoreactivity appeared to be more widespread, becoming very intense within epithelial cells affected by hydropic degeneration. Hyperkeratinized mucosa also showed HSP27 immunoreactivity, which was particularly intense in epithelial areas affected by hydropic degeneration. Western blot analysis confirmed HSP27, HSP72 and HSP73 expression in normal and in pre-ulcerative mucosa of the pars oesophagea. Semi-quantitative analysis showed that for all three HSPs the immunoreactivity was more intense in pre-ulcerative mucosa than in normal mucosa. The different expression patterns observed may have functional significance; further studies are needed, however, to define the role of HSPs in swine oesophagogastric lesions, the aetiology and pathogenesis of which are largely unknown.

Overexpression of Hsp27 in a human melanoma cell line: regulation of E-cadherin, MUC18/MCAM, and plasminogen activator (PA) system

Hsp27 is considered a potential marker for cell differentiation in diverse tissues. Several aspects linked to the differentiation process and to the transition from high to low metastatic potential were analyzed in melanoma cells transfected with Hsp27. E-cadherin plays a central role in cell differentiation, migration, and normal development. Loss of expression or function of E-cadherin has been documented in a variety of human malignancies. We observed by fluorescence-activated cell sorter (FACS) as well as immunofluorescence (IF) analysis a pronounced expression of E-cadherin in Hsp27-transfected A375 melanoma cells compared with control melanoma cells. The expression of the adhesion molecule MUC18/MCAM correlates directly with the metastatic potential of melanoma cells. In contrast to wild-type and neotransfected melanoma cells, in Hsp27-transfected cells the expression of MUC18/MCAM could not be detected by FACS and IF analysis. The plasminogen activator (PA) system plays a central role in mediating extracellular proteolysis and also in nonproteolytic events such as cell adhesion, migration, and transmembrane signaling. Hsp27 transfectants revealed elevated messenger ribonucleic acid expression of the urokinase-type PA (uPA) and its inhibitor, PA inhibitor type 1, which might indicate a neutralization effect of the proteolytic activity of uPA. Control cells failed to express both these molecules. The influence of Hsp27 expression on uPA activity and the involvement of E-cadherin could be demonstrated by use of anti-E-cadherin-blocking antibody. Our data provide evidence for an inhibitory-regulatory role of Hsp27 in tumor progression as found in our system.