HSP70 desensitizes osteosarcoma cells to baicalein and protects cells from undergoing apoptosis

Correlation of High-Grade Osteosarcoma Response to Chemotherapy with Enhanced Tissue Immunological Response: Analysis of CD95R, IFN-γ, Catalase, Hsp70, and VEGF

High-grade osteosarcoma, a primary malignant bone tumour, is experiencing a global increase in reported incidence with varied prevalence. Despite advances in management, which include surgery and neoadjuvant chemotherapy often an unsatisfactory outcome is found due to poor or heterogeneous response to chemotherapy. Our study delved into chemotherapy responses in osteosarcoma patients and associated molecular expressions, focusing on CD95 receptor (CD95R), interferon (IFN)-γ, catalase, heat-shock protein (Hsp)70, and vascular endothelial growth factor (VEGF). Employing immunohistochemistry and Huvos grading of post-chemo specimens, we analysed formalin-fixed paraffin-embedded (FFPE) osteosarcoma tissue of resected post-chemotherapy specimens from Dr. Soetomo General Academic Hospital in Surabaya, Indonesia (DSGAH), spanning from 2016 to 2020. Results revealed varied responses (poor 40.38%, moderate 48.08%, good 11.54%) and distinct patterns in CD95R, IFN-γ, catalase, Hsp70, and VEGF expression. Significant differences among response groups were observed in CD95R and IFN-γ expression in tumour-infiltrating lymphocytes. The trend of diminishing CD95R expression from poor to good responses, accompanied by an increase in IFN-γ, implied a reduction in the count of viable osteosarcoma cells with the progression of Huvos grading. Catalase expression in osteosarcoma cells was consistently elevated in the poor response group, while Hsp70 expression was highest. VEGF expression in macrophages was significantly higher in the good response group. In conclusion, this study enhances our understanding of immune-chemotherapy interactions in osteosarcoma and identifies potential biomarkers for targeted interventions.

Nanobiotechnological approaches in osteosarcoma therapy: Versatile (nano)platforms for theranostic applications

Constructive achievements in the field of nanobiotechnology and their translation into clinical course have led to increasing attention towards evaluation of their use for treatment of diseases, especially cancer. Osteosarcoma (OS) is one of the primary bone malignancies that affects both males and females in childhood and adolescence. Like other types of cancers, genetic and epigenetic mutations account for OS progression and several conventional therapies including chemotherapy and surgery are employed. However, survival rate of OS patients remains low and new therapies in this field are limited. The purpose of the current review is to provide a summary of nanostructures used in OS treatment. Drug and gene delivery by nanoplatforms have resulted in an accumulation of therapeutic agents for tumor cell suppression. Furthermore, co-delivery of genes and drugs by nanostructures are utilized in OS suppression to boost immunotherapy. Since tumor cells have distinct features such as acidic pH, stimuli-responsive nanoparticles have been developed to appropriately target OS. Besides, nanoplatforms can be used for biosensing and providing phototherapy to suppress OS. Furthermore, surface modification of nanoparticles with ligands can increase their specificity and selectivity towards OS cells. Clinical translation of current findings suggests that nanoplatforms have been effective in retarding tumor growth and improving survival of OS patients.

HSP70 inhibition suppressed glioma cell viability during hypoxia/reoxygenation by inhibiting the ERK1/2 and PI3K/AKT signaling pathways

Heat shock protein 70 (HSP70) can regulate astrocyte viability under hypoxic and ischemic conditions. However, the protective mechanism involved is not completely clear. This study aimed to investigate whether HSP70 protects U87 glioma cells against hypoxic damage via the extracellular signal-regulated kinases 1/2 (ERK1/2) and phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) signaling pathways. Lentivirus-mediated HSP70-siRNA was used for HSP70 silencing. U87 glioma cells with lentiviral infection were exposed to hypoxia for 4, 8, 12, and 24 h, respectively, followed by a 24-h reoxygenation treatment. A Cell-Counting Kit-8 was then used to evaluate the viability of the U87 glioma cells. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting were performed to determine the mRNA and protein levels, respectively. The expression of HSP70, p-ERK1/2, p-AKT, and U87 cell viability were increased after 8 h of hypoxia/24 h of reoxygenation (P < 0.01). However, HSP70 silencing significantly decreased the U87 cell viability after the hypoxia/reoxygenation treatment (P < 0.01). The protein expressions of p-ERK1/2 and p-AKT also decreased in HSP70-silenced U87 cells (P < 0.01). In conclusion, HSP70 inhibition suppressed the viability of U87 glioma cells during hypoxia/reoxygenation (at least partially) by inhibiting the ERK1/2 and PI3K/AKT signaling pathways. This study may help to understand the molecular mechanisms underlying the progression and development of cerebral hypoxia-ischemia.

Molecular Chaperones in Osteosarcoma: Diagnosis and Therapeutic Issues

Osteosarcoma (OS) is the most common form of primary bone tumor affecting mainly children and young adults. Despite therapeutic progress, the 5-year survival rate is 70%, but it drops drastically to 30% for poor responders to therapies or for patients with metastases. Identifying new therapeutic targets is thus essential. Heat Shock Proteins (HSPs) are the main effectors of Heat Shock Response (HSR), the expression of which is induced by stressors. HSPs are a large family of proteins involved in the folding and maturation of other proteins in order to maintain proteostasis. HSP overexpression is observed in many cancers, including breast, prostate, colorectal, lung, and ovarian, as well as OS. In this article we reviewed the significant role played by HSPs in molecular mechanisms leading to OS development and progression. HSPs are directly involved in OS cell proliferation, apoptosis inhibition, migration, and drug resistance. We focused on HSP27, HSP60, HSP70 and HSP90 and summarized their potential clinical uses in OS as either biomarkers for diagnosis or therapeutic targets. Finally, based on different types of cancer, we consider the advantage of targeting heat shock factor 1 (HSF1), the major transcriptional regulator of HSPs in OS.

The effect of baicalein on endoplasmic reticulum stress and autophagy on liver damage

Carbon tetrachloride (CCl₄) is a toxic chemical that causes liver injury. CCl₄ triggers endoplasmic reticulum (ER) stress and unfolded protein response (UPR). UPR triggers autophagy to deal with the damage. The aim of this study was to investigate the effect of baicalein, derived from Scutellaria baicalensis, on CCl₄-induced liver damage concerning ER stress and autophagy. Two groups of Wistar albino rats (n = 7/groups) were treated with 0.2 ml/kg CCl₄ for 10 days with and without baicalein. Histological and transmission electron microscopy (TEM) analysis, autophagy, and ER stress markers measurements were carried out to evaluate the effect of baicalein. Histological examinations showed that baicalein reduced liver damage. TEM analysis indicated that baicalein inhibited ER stress and triggered autophagy. CCl4-induced elevation of C/EBP homologous protein (CHOP), glucose-regulating protein 78 (GRP78), activating transcription factor 4 (ATF4), activating transcription factor 6 (ATF6), inositol requiring enzyme 1 (IRE1), pancreatic ER kinase (PERK), and active/spliced form of X-box-binding protein 1 (XBP1s) ER stress markers were decreased by baicalein. Baicalein also increased the autophagy-related 5 (ATG5), Beclin1, and Microtubule-associated protein 1A/1B-light chain 3-phosphatidylethanolamine-conjugated form (LC3-II) autophagy marker levels. In conclusion, baicalein reduced the CCl₄-induced liver damage by inhibiting ER stress and the trigger of autophagy.

Alantolactone suppresses human osteosarcoma through the PI3K/AKT signaling pathway

Osteosarcoma is the most common type of malignant bone cancer and results in cancer-related deaths among adolescents. Alantolactone (ALT) demonstrates antitumor properties in various diseases; however, its potential role in osteosarcoma is relatively unclear. The aim of the present study was to evaluate the effect of ALT on osteosarcoma. ALT significantly decreased the viability of U2OS and HOS osteosarcoma cell lines. Cells flow cytometry assay and Hoechst 33258 staining assay revealed that ALT significantly increased the proportion of apoptotic U2OS cells. In addition, wound healing and Transwell invasion assays demonstrated that the invasion and migration of osteosarcoma were markedly reduced upon ALT treatment. It was hypothesized that the antitumor functions of ALT are mediated through inhibition of the PI3K/AKT signaling pathway. In conclusion, the results of the present study confirmed the inhibition of ALT on osteosarcoma cells via downregulation of PI3K/AKT signaling pathways, suggesting ALT as a potential therapeutic candidate for osteosarcoma.

Molecular Targets of Genistein and Its Related Flavonoids to Exert Anticancer Effects

Increased health awareness among the public has highlighted the health benefits of dietary supplements including flavonoids. As flavonoids target several critical factors to exert a variety of biological effects, studies to identify their target-specific effects have been conducted. Herein, we discuss the basic structures of flavonoids and their anticancer activities in relation to the specific biological targets acted upon by these flavonoids. Flavonoids target several signaling pathways involved in apoptosis, cell cycle arrest, mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K)/AKT kinase, and metastasis. Polo-like kinase 1 (PLK1) has been recognized as a valuable target in cancer treatment due to the prognostic implication of PLK1 in cancer patients and its clinical relevance between the overexpression of PLK1 and the reduced survival rates of several carcinoma patients. Recent studies suggest that several flavonoids, including genistein directly inhibit PLK1 inhibitory activity. Later, we focus on the anticancer effects of genistein through inhibition of PLK1.

Overexpressed Hsp70 alleviated formaldehyde-induced apoptosis partly via PI3K/Akt signaling pathway in human bronchial epithelial cells

Formaldehyde (FA) is a ubiquitous environmental pollutant, which can induce apoptosis in lung cell and is related to the pathogenesis of asthma, pneumonia, and chronic obstructive pulmonary disease. Heat shock protein 70 (Hsp70) is an ATP-dependent molecular chaperone and exhibits an anti-apoptosis ability in a variety of cells. Previous studies reported that the expression of Hsp70 was induced when organisms were exposed to FA. Whether Hsp70 plays a role in the FA-induced apoptosis and the involved cell signaling pathway remain largely unknown. In this study, human bronchial epithelial cells with overexpressed Hsp70 and the control were exposed to different concentrations of FA (0, 40, 80, and 160 μmol/L) for 24 hours. Apoptosis and the expression levels of PI3K, Akt, p-Akt, MEK, p-MEK, and GLI2 were detected by Annexin-APC/7AAD double-labeled flow cytometry and western blot. The results showed that overexpression of Hsp70 decreased the apoptosis induced by FA and alleviated the decline of PI3k and p-Akt significantly. Inhibitor (LY 294002, a specific inhibitor of PI3K-Akt) test result indicated that PI3K-Akt signaling pathway was involved in the inhibition of FA-induced apoptosis by Hsp70 overexpression and also active in the maintenance of GLI2 level. However, it also suggested that other signaling pathways activated by overexpressed Hsp70 participated in this process, which was needed to be elucidated in further research.

ERK1/2 regulates heat stress-induced lactate production via enhancing the expression of HSP70 in immature boar Sertoli cells

Lactate produced by Sertoli cells plays an important role in spermatogenesis, and heat stress induces lactate production in immature boar Sertoli cells. Extracellular signaling regulated kinase 1 and 2 (ERK1/2) participates in heat stress response. However, the effect of ERK1/2 on heat stress-induced lactate production is unclear. In the present study, Sertoli cells were isolated from immature boar testis and cultured at 32 °C. Heat stress was induced in a 43 °C incubator for 30 min. Proteins and RNAs were detected by western blotting and RT-PCR, respectively. Lactate production and lactate dehydrogenase (LDH) activity were detected using commercial kits. Heat stress promoted ERK1/2 phosphorylation, showing a reducing trend with increasing recovery time. In addition, heat stress increased heat shock protein 70 (HSP70), glucose transporter 3 (GLUT3), and lactate dehydrogenase A (LDHA) expressions, enhanced LDH activity and lactate production at 2-h post-heat stress. Pretreatment with U0126 (1 × 10-6 mol/L), a highly selective inhibitor of ERK1/2 phosphorylation, reduced HSP70, GLUT3, and LDHA expressions and decreased LDH activity and lactate production. Meanwhile, ERK2 siRNA1 reduced the mRNA level of ERK2 and weakened ERK1/2 phosphorylation. Additionally, ERK2 siRNA1 reduced HSP70, GLUT3, and LHDA expressions decreased LDH activity and lactate production. Furthermore, HSP70 siRNA3 downregulated GLUT3 and LDHA expressions and decreased LDH activity and lactate production. These results show that activated ERK1/2 increases heat stress-induced lactate production by enhancing HSP70 expression to promote the expressions of molecules related to lactate production (GLUT3 and LDHA). Our study reveals a new insight in reducing the negative effect of heat stress in boars.

Inducible HSP70 antagonizes cisplatin‑induced cell apoptosis through inhibition of the MAPK signaling pathway in HGC‑27 cells

Inducible heat shock protein 70 (HSP70; also known as HSPA1 or HSP72) is implicated in cancer. As a stress-inducible heat shock protein, HSP70 is highly expressed in a variety of cancers and correlates with metastasis, chemotherapy resistance and tumor prognosis. The present study demonstrated that suppression of HSP70 through the specific inhibitor pifithrin-µ or by HSP70 knockdown enhanced cisplatin-induced apoptosis in HGC-27 gastric cancer cells. By contrast, upregulation of HSP70 through transfection of a HSP70 overexpressing plasmid decreased cisplatin-induced HGC-27 cell apoptosis. In exploring the underlying molecular mechanisms, the present results revealed that HSP70 antagonized cisplatin-induced HGC-27 cell apoptosis by regulating the mitogen-activated protein kinase (MAPK) signaling pathway. In addition, suppressing the MAPK pathway enhanced cisplatin-induced HGC-27 cell apoptosis. Collectively, the present findings suggest that inhibition of HSP70 expression enhanced the sensitivity of HGC-27 cells to cisplatin via the MAPK signaling pathway, and that HSP70 may serve as a potential therapeutic target in gastric cancer.

miR-223/Hsp70/JNK/JUN/miR-223 feedback loop modulates the chemoresistance of osteosarcoma to cisplatin

Osteosarcoma (OS) is a primary bone malignancy with a five-year survival rate of 60%; the chemoresistance of OS still remains a huge challenge. Heat shock protein 70 (Hsp70), a member of HSP family, is overexpressed in OS cell lines and involved in the resistance of OS cell lines. In addition, miRNAs have been involved in the carcinogenesis and chemoresistance of OS; of them, miR-223 has been reported to be underexpressed and serve as a tumor suppressor in OS through targeting Hsp90B1, also a member of HSP family. Herein, online tools predicted that Hsp70 might be a direct target of miR-223. In the present study, miR-223 expression was down-regulated in OS tissues and cell lines; miR-223 overexpression enhanced the cellular effects of cisplatin (CDDP) on OS cell lines. Through binding to the HSPA1A 3'UTR, miR-223 could regulate Hsp70 protein levels and downstream JNK/JUN signaling pathway, thus modulating OS cell apoptosis through Hsp70 under CDDP stress. Finally, JUN, a downstream transcription factor of JNK signaling, could bind to the promoter region of miR-223 to promote its transcription. In summary, miR-223, Hsp70 and downstream JNK/JUN formed a feedback loop to modulate the chemoresistance of OS to CDDP.

β-Escin inhibits the proliferation of osteosarcoma cells via blocking the PI3K/Akt pathway

β-Escin exhibits anticancer effects on a panel of established cancer cells. However, the effects of β-escin on human osteosarcoma (OS) are still unknown. The aim of the present study was to investigate whether β-escin was effective against OS both in vivo and in vitro. Our results showed that β-escin induced dose- and time-dependent effects against MG-63, OS732, U-2OS, HOS and SAOS-2 cell proliferation. β-Escin also exhibited excellent anti-proliferative and pro-apoptotic effects in an established OS xenograft model. β-Escin and cytotoxic drugs, including cisplatin, methotrexate (MTX), doxorubicin (Dox) and ifosfamide (Ifos), synergistically inhibited proliferation of MG-63 and OS732 cells in vitro. Moreover, β-escin induced apoptotic death, activated caspase-3, caspase-8 and caspase-9, and regulated expression of Bax and Bcl-2 in MG-63 cells. In addition, our results showed that β-escin treatment reduced expression of p-PI3K, p-Akt and p-mTOR both in MG-63 cells and in an MG-63 xenograft OS model. Interestingly, SC79, which is an Akt activator, inhibited the anti-proliferative effects of β-escin on MG-63 cells. Taken together, our data support the conclusion that β-escin effectively inhibits OS proliferation both in vivo and in vitro. The inhibitory effect of β-escin, at least in part, is due to the inactivation of the PI3K/Akt signalling pathway.

β-Escin exhibits anticancer effects on a panel of established cancer cells. However, the effects of β-escin on human osteosarcoma (OS) are still unknown.

Proteomic identification of proteins differentially expressed following overexpression of hTERT (human telomerase reverse transcriptase) in cancer cells

Reverse transcriptase activity of telomerase adds telomeric repeat sequences at extreme ends of the newly replicated chromosome in actively dividing cells. Telomerase expression is not detected in terminally differentiated cells but is noticeable in 90% of the cancer cells. hTERT (human telomerase reverse transcriptase) expression seems to promote invasiveness of cancer cells. We here present proteomic profiles of cells overexpressing or knocked down for hTERT. This study also attempts to find out the potential interacting partners of hTERT in cancer cell lines. Two-dimensional gel electrophoresis (2-DE) of two different cell lines U2OS (a naturally hTERT negative cell line) and HeLa revealed differential expression of proteins in hTERT over-expressing cells. In U2OS cell line 28 spots were picked among which 23 spots represented upregulated and 5 represented down regulated proteins. In HeLa cells 21 were upregulated and 2 were down regulated out of 23 selected spots under otherwise identical experimental conditions. Some heat shock proteins viz. Hsp60 and Hsp70 and GAPDH, which is a housekeeping gene, were found similarly upregulated in both the cell lines. The upregulation of these proteins were further confirmed at RNA and protein level by real-time PCR and western blotting respectively.

Production of Bacalin, Bacalein and Wogonin in Hairy Root Culture of American Skullcap (Scutellaria lateriflora)by Auxin Treatment

ABSTRACT: The hairy root culture of American Skullcap (Scutellaria lateriflora) was studied to investigate the biomass and flavonoids content (baicalin, baicalein and wogonin) in response of various auxin concentrations.The growth rates of the hairy roots varied significantly only at IBA 0.1 mg/L and for all other auxin treatments did not vary significantly. The biomass of hairy roots was 8% higher when treated with IBA 0.1 mg/L and biomass was almost similar and slightly lower levels when treated with various IAA concentration and NAA, respectively. However, the auxins treatments responsed positively to increase flavone production in American Skullcaphairy root culture. The auxin indole-3-butyric acid (IBA) at 1 mg/L performed the best for the accumulation of baicalin and wogonin. The auxin IBA at 1 mg/L accumulated 1.64 and 2.92 times higher baicalin and wogonin, respectively compared to control treatment. Meanwhile, the highest levels of baicalein were observed for hair root cultures in the presence of 1-naphthaleneacetic acid (NAA) at 0.1 mg/L achieving 2.38 times higher than that of accumulated in the control. These findings indicate that hairy root cultures of S. lateriflorausing liquid 1/2MS medium supplemented with auxin could be a valuable alternative approach for flavonoid production.

Inhibiting reactive oxygen species-dependent autophagy enhanced baicalein-induced apoptosis in oral squamous cell carcinoma

Autophagy modulation has been considered a potential therapeutic strategy for oral squamous cell carcinoma (OSCC). A previous study confirmed that baicalein might possess significant anti-carcinogenic activity. However, whether baicalein induces autophagy and its role in cell death in OSCC are still unclear. The aim of this study was to investigate the anticancer activity and molecular targets of baicalein in OSCC in vitro. In this study, we found that baicalein induced significant apoptosis in OSCC cells Cal27. In addition to showing apoptosis induction, we also demonstrated baicalein-induced autophagic response in Cal27 cells. Moreover, pharmacologically or genetically blocking autophagy enhanced baicalein-induced apoptosis, indicating the cytoprotective role of autophagy in baicalein-treated Cal27 cells. Importantly, we found that baicalein triggered reactive oxygen species (ROS) generation in Cal27 cells. Furthermore, N-acetyl-cysteine, a ROS scavenger, abrogated the effects of baicalein on ROS-dependent autophagy. Therefore, we found that baicalein increased autophagy through the promotion of ROS signaling pathways in OSCC. These data also suggest that a strategy of blocking ROS-dependent autophagy to enhance the activity of baicalein warrants further attention for the treatment of OSCC.

Targeting HSP70 and GRP78 in canine osteosarcoma cells in combination with doxorubicin chemotherapy

Heat shock proteins (HSPs) are molecular chaperones subdivided into several families based on their molecular weight. Due to their cytoprotective roles, these proteins may help protect cancer cells against chemotherapy-induced cell death. Investigation into the biologic activity of HSPs in a variety of cancers including primary bone tumors, such as osteosarcoma (OSA), is of great interest. Both human and canine OSA tumor samples have aberrant production of HSP70. This study assessed the response of canine OSA cells to inhibition of HSP70 and GRP78 by the ATP-mimetic VER-155008 and whether this treatment strategy could sensitize cells to doxorubicin chemotherapy. Single-agent VER-155008 treatment decreased cellular viability and clonogenic survival and increased apoptosis in canine OSA cell lines. However, combination schedules with doxorubicin after pretreatment with VER-155008 did not improve inhibition of cellular viability, apoptosis, or clonogenic survival. Treatment with VER-155008 prior to chemotherapy resulted in an upregulation of target proteins HSP70 and GRP78 in addition to the co-chaperone proteins Herp, C/EBP homologous transcription protein (CHOP), and BAG-1. The increased GRP78 was more cytoplasmic in location compared to untreated cells. Single-agent treatment also revealed a dose-dependent reduction in activated and total Akt. Based on these results, targeting GRP78 and HSP70 may have biologic activity in canine osteosarcoma. Further studies are required to determine if and how this strategy may impact the response of osteosarcoma cells to chemotherapy.

The Fascinating Effects of Baicalein on Cancer: A Review

Cancer is one of the leading causes of death worldwide and a major global health problem. In recent decades, the rates of both mortality and morbidity of cancer have rapidly increased for a variety of reasons. Despite treatment options, there are serious side effects associated with chemotherapy drugs and multiple forms of drug resistance that significantly reduce their effects. There is an accumulating amount of evidence on the pharmacological activities of baicalein (e.g., anti-inflammatory, antioxidant, antiviral, and antitumor effects). Furthermore, there has been great progress in elucidating the target mechanisms and signaling pathways of baicalein's anti-cancer potential. The anti-tumor functions of baicalein are mainly due to its capacities to inhibit complexes of cyclins to regulate the cell cycle, to scavenge oxidative radicals, to attenuate mitogen activated protein kinase (MAPK), protein kinase B (Akt) or mammalian target of rapamycin (mTOR) activities, to induce apoptosis by activating caspase-9/-3 and to inhibit tumorinvasion and metastasis by reducing the expression of matrix metalloproteinase-2/-9 (MMP-2/-9). In this review, we focused on the relevant biological mechanisms of baicalein involved in inhibiting various cancers, such as bladder cancer, breast cancer, and ovarian cancer. Moreover, we also summarized the specific mechanisms by which baicalein inhibited the growth of various tumors in vivo. Taken together, baicalein may be developed as a potential, novel anticancer drug to treat tumors.

Cell apoptosis, autophagy and necroptosis in osteosarcoma treatment

Osteosarcoma is the most common primary bone tumor in children and adolescents. Although combined therapy including surgery and multi-agent chemotherapy have resulted in great improvements in the overall survival of patients, chemoresistance remains an obstacle for the treatment of osteosarcoma. Molecular targets or effective agents that are actively involved in cell death including apoptosis, autophagy and necroptosis have been studied. We summarized how these agents (novel compounds, miRNAs, or proteins) regulate apoptotic, autophagic and necroptotic pathways; and discussed the current knowledge on the role of these new agents in chemotherapy resistance in osteosarcoma.

[Inhibiting HSP70 expression enhances cisplatin sensitivity of cervical cancer cells]

OBJECTIVE

To investigate the relationship between sensitivity to cisplatin (DDP) and the expression of HSP70 in cervical cancer cells in vitro.

METHODS

Cervical cancer Hela229 cells treated with different concentrations of DDP and the HSP70 inhibitor (PFT-µ) were examined for cell viability using MTT assay and colony forming ability. The cell apoptosis was analyzed by flow cytometry with propidium iodide staining and DAPI staining, and JC-1 staining was used to determine mitochondrial membrane potential. The expressions of HSP70, Bcl-2, Bax and caspase-3 were measured with Western blotting. A nude mouse model bearing Hela229 cell xenograft was used to evaluate the effect of DDP and PFT-µ on tumor growth.

RESULTS

Hela229 cells expressed a higher level of HSP70 than normal cervical cells. The combined use of PFT-µ significantly enhanced the inhibitory effect of DDP (P<0.01) and increased the cell apoptosis in Hela229 cells. JC-1 staining demonstrated that DDP combined with PFT-µ more obviously reduced mitochondrial membrane potential. DDP combined with PFT-µ more strongly lowered Bcl-2 expression and increased the expressions of casepase-3 and Bax than DDP alone. In the nude mouse model, PFT-µ significantly enhanced DDP sensitivity of Hela229 cell xenografts (P<0.01).

CONCLUSIONS

Inhibition of HSP70 expression can enhance the sensitivity of cervical cancer cell to DDP both in vivo and in vitro possibly by promoting cell apoptosis, suggesting the potential of HSP70 as a new target for gene therapy of cervical cancer.

Hsp70 plays an important role in high-fat diet induced gestational hyperglycemia in mice

Gestational diabetes mellitus (GDM) has emerged as an epidemic disease during the last decade, affecting about 2 to 5% pregnant women. Even among women who have gestational hyperglycemia may also be positively related to adverse outcomes as GDM. Since heat shock protein (Hsp) 70 has been reported to be associated with diabetes and insulin resistance and its expression was reported to be negatively regulated by the membrane-permeable Hsp70 inhibitor MAL3-101 while positively regulated by the Hsp70 activator BGP-15, we investigated whether Hsp70 played a role in a gestational hyperglycemia mouse model. Mice were divided into non-pregnant and pregnant groups, and each comprised three subgroups: control, high-fat diet (HFD) + MAL3-101, and HFD + BGP-15. We examined the serum levels of triglycerides, total cholesterol, glucose, and insulin, as well as conducted thermal detection of brown adipose tissue (BAT). The role of Hsp70 in BAT apoptosis was also investigated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and caspase-3 staining. Higher serum level of Hsp70 was associated with increased bodyweight gain after pregnancy in mice fed HFD. Circulating Hsp70 was elevated in control pregnant mice compared to control non-pregnant mice. BGP-induced serum Hsp70 expression reduced triglycerides, total cholesterol, glucose, and insulin levels in the serum. Additionally, thermal detection of BAT, TUNEL, and caspase-3 staining revealed relationship correlation between Hsp70 and BAT functions. Hsp70 level is associated with hyperglycemia during pregnancy. Our results support the role of Hsp70 in facilitating BAT activities and protecting BAT cells from apoptosis via caspase-3 pathway.

Application of eupatilin in the treatment of osteosarcoma

5,7-dihydroxy-3',4',6-trimethoxyflavone, commonly known as eupatilin, is a traditional Asian medicinal plant, which is mainly used for the treatment of gastritis, as well as its use as an anti-inflammatory agent. Eupatilin is a bioactive compound; however, its effects on osteosarcoma (OS) have remained to be elucidated. Therefore, the present study aimed to investigate the effects of eupatilin on this malignant bone tumor, using the U-2 OS cell line. The experimental results revealed that eupatilin inhibited U-2 OS cell growth in a concentration-dependent manner and induced G2/M phase cell cycle arrest and apoptosis. Additionally, western blot analysis indicated that eupatilin was able to trigger the mitochondrial apoptotic pathway, demonstrated by the enhanced Bax/B cell lymphoma-2 ratio, decrease in mitochondrial membrane potential, release of cytochrome c, caspase-3 and -9 activation and poly(ADP-ribose)polymerase cleavage detected in the U-2 OS cells. These results indicated that eupatilin was able to inhibit U-2 OS cancer cell proliferation by the induction of apoptosis via the mitochondrial intrinsic pathway. Eupatilin may therefore represent a novel anticancer drug for use in the treatment of osteosarcoma.

PI3K/Akt signaling mediated Hexokinase-2 expression inhibits cell apoptosis and promotes tumor growth in pediatric osteosarcoma

Accumulating evidence has shown that PI3K/Akt pathway is frequently hyperactivated in osteosarcoma (OS) and contributes to tumor initiation and progression. Altered phenotype of glucose metabolism is a key hallmark of cancer cells including OS. However, the relationship between PI3K/Akt pathway and glucose metabolism in OS remains largely unexplored. In this study, we showed that elevated Hexokinase-2 (HK2) expression, which catalyzes the first essential step of glucose metabolism by conversion of glucose into glucose-6-phosphate, was induced by activated PI3K/Akt signaling. Immunohistochemical analysis showed that HK2 was overexpressed in 83.3% (25/30) specimens detected and was closely correlated with Ki67, a cell proliferation index. Silencing of endogenous HK2 resulted in decreased aerobic glycolysis as demonstrated by reduced glucose consumption and lactate production. Inhibition of PI3K/Akt signaling also suppressed aerobic glycolysis and this effect can be reversed by reintroduction of HK2. Furthermore, knockdown of HK2 led to increased cell apoptosis and reduced ability of colony formation; meanwhile, these effects were blocked by 2-Deoxy-d-glucose (2-DG), a glycolysis inhibitor through its actions on hexokinase, indicating that HK2 functions in cell apoptosis and growth were mediated by altered aerobic glycolysis. Taken together, our study reveals a novel relationship between PI3K/Akt signaling and aerobic glycolysis and indicates that PI3K/Akt/HK2 might be potential therapeutic approaches for OS.

PI3K/Akt signaling in osteosarcoma

Osteosarcoma (OS) is the most common nonhematologic bone malignancy in children and adolescents. Despite the advances of adjuvant chemotherapy and significant improvement of survival, the prognosis remains generally poor. As such, the search for more effective anti-OS agents is urgent. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway is thought to be one of the most important oncogenic pathways in human cancer. An increasing body of evidence has shown that this pathway is frequently hyperactivated in OS and contributes to disease initiation and development, including tumorigenesis, proliferation, invasion, cell cycle progression, inhibition of apoptosis, angiogenesis, metastasis and chemoresistance. Inhibition of this pathway through small molecule compounds represents an attractive potential therapeutic approach for OS. The aim of this review is to summarize the roles of the PI3K/Akt pathway in the development and progression of OS, and to highlight the therapeutic potential of targeting this signaling pathway. Knowledge obtained from the application of these compounds will help in further understanding the pathogenesis of OS and designing subsequent treatment strategies.

Proteomic analysis of human sonic hedgehog (SHH) medulloblastoma stem-like cells

First proteomic characterization of sonic hedgehog human medulloblastoma stem-like cells.