The clinicopathological significance of heat shock protein 70 and glutamine synthetase expression in hepatocellular carcinoma

Evaluating the diagnostic accuracy of heat shock proteins and their combination with Alpha-Fetoprotein in the detection of hepatocellular carcinoma: a meta-analysis

BACKGROUND

A growing body of research suggests that heat shock proteins (HSPs) may serve as diagnostic biomarkers for hepatocellular carcinoma (HCC), but their results are still controversial. This meta-analysis endeavors to evaluate the diagnostic accuracy of HSPs both independently and in conjunction with alpha-fetoprotein (AFP) as novel biomarkers for HCC detection.

METHODS

Pooled statistical indices, including sensitivity, specificity, diagnostic odds ratio (DOR), positive likelihood ratio (PLR), and negative likelihood ratio (NLR) with 95% confidence intervals (CI), were computed to assess the diagnostic accuracy of HSPs, AFP, and their combinations. Additionally, the area under the summary receiver operating characteristic (SROC) curve (AUC) was determined.

RESULTS

A total of 2013 HCC patients and 1031 control subjects from nine studies were included in this meta-analysis. The summary estimates for HSPs and AFP are as follows: sensitivity of 0.78 (95% CI: 0.69-0.85) compared to 0.73 (95% CI: 0.65-0.80); specificity of 0.89 (95% CI: 0.81-0.95) compared to 0.86 (95% CI: 0.77-0.91); PLR of 7.4 (95% CI: 3.7-14.9) compared to 5.1 (95% CI: 3.3-8.1); NLR of 0.24 (95% CI: 0.16-0.37) compared to 0.31 (95% CI: 0.24-0.41); DOR of 30.19 (95% CI: 10.68-85.37) compared to 16.34 (95% CI: 9.69-27.56); and AUC of 0.90 (95% CI: 0.87-0.92) compared to 0.85 (95% CI: 0.82-0.88). The pooled sensitivity, specificity, PLR, NLR, DOR and AUC were 0.90 (95% CI: 0.82-0.95), 0.94 (95% CI: 0.82-0.98), 14.5 (95% CI: 4.6-45.4), 0.11 (95% CI: 0.06-0.20), 133.34 (95% CI: 29.65-599.61), and 0.96 (95% CI: 0.94-0.98) for the combination of HSPs and AFP.

CONCLUSION

Our analysis suggests that HSPs have potential as a biomarker for clinical use in the diagnosis of HCC, and the concurrent utilization of HSPs and AFP shows notable diagnostic effectiveness for HCC.

Decoding the roles of heat shock proteins in liver cancer

Hepatocellular carcinoma (HCC) is one of the most common gastrointestinal malignancies, characterized by insidious onset and high propensity for metastasis and recurrence. Apart from surgical resection, there are no effective curative methods for HCC in recent years, due to resistance to radiotherapy and chemotherapy. Heat shock proteins (HSP) play a crucial role in maintaining cellular homeostasis and normal organism development as molecular chaperones for intracellular proteins. Both basic research and clinical data have shown that HSPs are crucial participants in the HCC microenvironment, as well as the occurrence, development, metastasis, and resistance to radiotherapy and chemotherapy in various malignancies, particularly liver cancer. This review aims to discuss the molecular mechanisms and potential clinical value of HSPs in HCC, which may provide new insights for HSP-based therapeutic interventions for HCC.

Targeting HSP70 chaperones by rhein sensitizes liver cancer to artemisinin derivatives

BACKGROUND

Liver cancer is one of common types of cancer with poor prognosis and limited therapies. Heat shock proteins (HSP) are molecular chaperones that have important roles in tumorigenesis, and emerging as therapeutic targets. Artemisinin and rhein are natural agents from Artemisia annua L. and Rheum undulatum L., respectively. Both rhein and artemisinin have anticancer effects; however, the molecular targets of rhein remain to be identified. It is also unclear whether rhein can synergize with artemisinin derivatives to inhibit liver cancer.

PURPOSE

We aim to identify the targets of rhein in the treatment of hepatocarcinoma and determine the effects of combining rhein and artemisinin derivatives on liver cancer cells.

METHODS

The targets of rhein were detected by mass spectrometry and validated by rhein-proteins interaction assays. The effects of rhein on the chaperone activity of HSP72/HSC70/GRP78 were determined by luciferase refolding assays. Cell viability and apoptosis were determined by CCK8 and flow cytometry assays. For in vivo study, xenograft tumor models were established and treated with rhein and artesunate. Tumor growth was monitored regularly.

RESULTS

Mass spectrometry analysis of rhein-binding proteins in HepG2 cells revealed that HSP72, HSC70 and GRP78 were more profoundly pulled down by rhein-crosslinked sepharose 4B beads compared to the control beads. Further experiments demonstrated that rhein directly interacted with HSP72/HSC70/GRP78 proteins, and inhibit their activity of refolding denatured luciferase. Meanwhile, rhein induced proteasomal degradation of HIF1α and β-catenin. Artesunate or dihydroartemisinin in combination with knockdown of both HSP72 and HSC70 significantly inhibited cell viability. The HSP70/HSC70/GRP78 inhibitors VER-155,008 and rhein phenocopied HSP72/HSC70 knockdown, synergizing with artesunate or dihydroartemisinin to inhibit hepatocarcinoma cell viability. Combinatorial treatment with rhein and artemisinin derivatives significantly induced hepatocarcinoma cell apoptosis, and inhibited tumor growth in vivo.

CONCLUSIONS

The current study demonstrates that rhein is a novel HSP72/HSC70/GRP78 inhibitor that suppresses the chaperone activity of HSP70s. Dual inhibition of HSP72 and HSC70 can enhance the sensitivity of hepatocarcinoma cells to artemisinin derivatives. Combined treatment with artemisinin derivative and rhein significantly inhibits hepatocarcinoma. Artemisinin derivatives in combination with dual inhibition of HSP72 and HSC70 represents a new approach to improve cancer therapy.

Glutamine synthetase and hepatocellular carcinoma

Glutamine synthetase (GS) is an enzyme that converts ammonia and glutamate to glutamine using adenosine triphosphate. GS is expressed in the brain, kidney, and liver tissues under normal physiological conditions. GS is involved in abnormal lipid metabolism of the liver by catalyzing de novo synthesis of glutamine, thereby inducing liver inflammation. Metabolic dysfunction-associated steatotic liver diseases (MASLD), such as Metabolic Associated Fatty Liver Disease and Metabolic Associated Steato Hepatitis, are considered risk factors for HCC. GS may also be involved in the development and progression of hepatocellular carcinoma (HCC) through other signaling pathways, including the rapamycin (mTOR) and Wnt/β-catenin signaling pathways. Furthermore, the correct combination of HSP70, GPC3, and GS can improve the accuracy and precision of HCC diagnosis. However, the prognostic value of GS in different HCC populations remains controversial. The expression of GS affects the sensitivity of HCC cells to radiotherapy and chemotherapy. In addition, immunotherapy has been approved for the treatment of advanced HCC. This article delves into the development and application of GS in HCC, laying a theoretical foundation for the subsequent exploration of GS as a potential target for treating HCC.

Glutamine metabolic reprogramming in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a lethal disease with limited management strategies and poor prognosis. Metabolism alternations have been frequently unveiled in HCC, including glutamine metabolic reprogramming. The components of glutamine metabolism, such as glutamine synthetase, glutamate dehydrogenase, glutaminase, metabolites, and metabolite transporters, are validated to be potential biomarkers of HCC. Increased glutamine consumption is confirmed in HCC, which fuels proliferation by elevated glutamate dehydrogenase or upstream signals. Glutamine metabolism also serves as a nitrogen source for amino acid or nucleotide anabolism. In addition, more glutamine converts to glutathione as an antioxidant in HCC to protect HCC cells from oxidative stress. Moreover, glutamine metabolic reprogramming activates the mTORC signaling pathway to support tumor cell proliferation. Glutamine metabolism targeting therapy includes glutamine deprivation, related enzyme inhibitors, and transporters inhibitors. Together, glutamine metabolic reprogramming plays a pivotal role in HCC identification, proliferation, and progression.

Clinicopathological and prognostic significance of heat shock proteins in hepatocellular carcinoma: a systematic review and meta-analysis

Background

Overexpression of heat shock proteins (HSPs) has been observed in a wide range of human tumors, and there is an increasing evidence demonstrated that HSPs play a key role in tumor progression. Several studies were conducted to explore the clinicopathological characteristics and prognostic value of HSPs in hepatocellular carcinoma (HCC), but the results remain controversial. To address this gap, we conducted a systematic review and meta-analysis.

Methods

The eligible literature was obtained from PubMed, Cochrane library, Web of science, Embase, Chinese National Knowledge Infrastructure and Wan Fang databases. We used the odds ratio (OR) and hazard ratio (HR) as the suitable parameters to assess the clinicopathological features and prognostic value of HSPs in HCC patients.

Results

The meta-analysis results showed that HSPs expression was associated with overall survival (OS) of HCC patients (HR = 1.61, 95%CI = 1.22-2.13, P=0.001, I 2 = 62.7%). In addition, the pooled results suggested that HSPs expression was significantly correlated with tumor differentiation (OR = 1.33, 95%CI = 1.08-1.65, P = 0.907), vascular invasion (OR = 1.31, 95%CI = 1.02-1.69, P = 0.921) and lymphatic metastasis (OR=1.98, 95%CI= 1.70-2.31, P = 0.740). Meanwhile, the subgroup analysis showed a significant correlation between the expression of HSP27 (HR=1.69, 95%CI = 1.24-2.31, P = 0.674) and HSP90α (HR=2.03, 95%CI = 1.73-2.40, P = 0.743) with OS of HCC patients.

Conclusions

Our meta-analysis confirms that HSPs expression is closely associated with a worse prognosis in HCC patients, and may be directly involved in tumor differentiation and distant metastasis. In addition, the subgroup analysis results demonstrate that the expression of HSP27 and HSP90α can be served as potential prognostic predictors of HCC.

HSP70-eIF4G Interaction Promotes Protein Synthesis and Cell Proliferation in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide and features various tumor escape mechanisms from treatment-induced stress. HSP70 plays a critical role in cell protection under stress. eIF4G physiologically regulates the formation of the protein-ribosomal complex and maintains cellular protein synthesis. However, the precise cooperation of both in HCC remains poorly understood. In this study, we demonstrate that HSP70 expression is positively correlated with eIF4G in tumor specimens from 25 HCC patients, in contrast to the adjacent non-tumorous tissues, and that both influence the survival of HCC patients. Mechanistically, this study indicates that HSP70 and eIF4G interact with each other in vitro. We further show that the HSP70–eIF4G interaction contributes to promoting cellular protein synthesis, enhancing cell proliferation, and inhibiting cell apoptosis. Collectively, this study reveals the pivotal role of HSP70–eIF4G interaction as an escape mechanism in HCC. Therefore, modulation of the HSP70–eIF4G interaction might be a potential novel therapeutic target of HCC treatment.

Heat-Shock protein A12A is a novel PCNA-binding protein and promotes hepatocellular carcinoma growth

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death. Proliferating cell nuclear antigen (PCNA) plays a pivotal role in cancer development and progression. However, the long-term dismal prognosis of HCC mandates more investigation to identify novel regulators in HCC pathogenesis. Heat-shock protein A12A (HSPA12A) encodes a novel member of the HSP70 family. Here, we report that HCC cells showed increased HSPA12A expression, and overexpression of HSPA12A promoted HCC growth and angiogenesis in mice. Gain- and loss-of-functional studies demonstrated that the proliferation of HCC HepG2 cells, as well as β-catenin expression and nuclear translocation, was promoted by HSPA12A overexpression, but in turn suppressed by HSPA12A knockdown. HSPA12A did not impact PCNA expression; however, mass spectrometry and co-immunoprecipitation immunoblotting analysis revealed that HSPA12A directly binds to PCNA and promotes its trimerization, which is an essential functional conformation of PCNA for carcinogenesis. Importantly, PCNA inhibition by PCNA-I1 reversed the HSPA12A-mediated HepG2 cell differentiation. These findings indicate that HSPA12A is a novel regulator of HCC cell proliferation and tumor growth through binding to PCNA for its trimerization. HSPA12A inhibition might represent a viable strategy for the management of HCC in humans.

Cytosolic Hsp70 as a biomarker to predict clinical outcome in patients with glioblastoma

INTRODUCTION

The major stress-inducible heat shock protein 70 (Hsp70) is induced after different stress stimuli. In tumors, elevated intracellular Hsp70 levels were associated on the one hand with radio- and chemotherapy resistance and on the other hand with a favorable outcome for patients. This study was undertaken to investigate cytosolic Hsp70 (cHsp70) as a potential biomarker for progression free (PFS) and overall survival (OS) in patients with primary glioblastomas (GBM).

METHODS

The cHsp70 expression in tumor tissue of 60 patients diagnosed with primary GBM was analyzed by immunohistochemistry. The cHsp70 expression was correlated to the PFS and OS of the patients.

RESULTS

A high cHsp70 expression was associated with a prolonged PFS (hazard ratio = 0.374, p = 0.001) and OS (hazard ratio = 0.416, p = 0.014) in GBM patients treated according to the standard Stupp protocol with surgery, radiotherapy and temozolomide.

CONCLUSIONS

These data suggest that the intracellular Hsp70 expression might serve as a prognostic marker in patients with primary GBM.

The Molecular Chaperone Heat Shock Protein 70 Controls Liver Cancer Initiation and Progression by Regulating Adaptive DNA Damage and Mitogen-Activated Protein Kinase/Extracellular Signal-Regulated Kinase Signaling Pathways

Delineating the mechanisms that drive hepatic injury and hepatocellular carcinoma (HCC) progression is critical for development of novel treatments for recurrent and advanced HCC but also for the development of diagnostic and preventive strategies. Heat shock protein 70 (HSP70) acts in concert with several cochaperones and nucleotide exchange factors and plays an essential role in protein quality control that increases survival by protecting cells against environmental stressors. Specifically, the HSP70-mediated response has been implicated in the pathogenesis of cancer, but the specific mechanisms by which HSP70 may support malignant cell transformation remains to be fully elucidated. Here, we show that genetic ablation of HSP70 markedly impairs HCC initiation and progression by distinct but overlapping pathways. This includes the potentiation of the carcinogen-induced DNA damage response, at the tumor initiation stage, to increase the p53-dependent surveillance response leading to the cell cycle exit or death of genomically damaged differentiated pericentral hepatocytes, and this may also prevent their conversion into more proliferating HCC progenitor cells. Subsequently, activation of a mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) negative feedback pathway diminishes oncogenic signals, thereby attenuating premalignant cell transformation and tumor progression. Modulation of HSP70 function may be a strategy for interfering with oncogenic signals driving liver cell transformation and tumor progression, thus providing an opportunity for human cancer control.

Concomitant use of heat-shock protein 70, glutamine synthetase and glypican-3 is useful in diagnosis of HBV-related hepatocellular carcinoma with higher specificity and sensitivity

Hepatocellular carcinoma is the third leading cause of cancer-related death worldwide and late diagnosis is the main cause of death in HCC patients. In this study expression patterns of HSP70, GPC3 and GS and their relationships with pathogenesis of HCC in Iranian patients were investigated. The expression of HSP70, GPC3 and GS were determined by immunohistochemistry and quantitative real-time PCR (q-PCR) methods, using 121 cases from patients with HBV alone, HCC without HBV, HBV+HCC and 30 normal tissues as control group. HSP70, GPC3 and GS were expressed in higher levels in HBV-related HCC samples compared to HBV alone group. The results showed that the labeling index of HSP70, GPC3 and GS are correlated with immunohistochemical and molecular expressions of HSP70, GPC3 and GS. The sensitivity and specificity for HCC diagnosis were 43.4% and 89.7% for HSP70, 64.3% and 90.4% for GPC3, and 60.7% and 94.3% for GS, respectively. The sensitivity and specificity of the panels with 3, 2 and 1 positive markers, regardless of which one, were 21.6% and 100%, 51.3% and 100% and 93.4% and 80.5% respectively. The current study demonstrated an association between HSP70, GPC3 and GS expressions and HBV-related HCC in our population. It was concluded that HSP70, GPC3 and GS expressions could be useful biomarkers for increasing the specificity and sensitivity of HCC diagnosis to acceptable level. Also, proper combinations of these 3 markers could improve diagnostic accuracy.

Deregulation of miR-34a and Its Chaperon Hsp70 in Hepatitis C virus-Induced Liver Cirrhosis and Hepatocellular Carcinoma Patients

Background: MicroRNA deregulation may occur during hepatocellular carcinoma (HCC) genesis and progression stages. MicroRNA-34a (miR-34a) functions as a tumor suppressor and is down-regulated or silenced in a variety of human cancers, while heat shock proteins (Hsps) play important roles in assisting protein folding and preventing both protein aggregation and transport across membranes. The present study aimed to evaluating serum expression of miR-34a and its target Hsp70 for early detection of HCC in patients with liver cirrhosis (LC), focusing on correlations with clinicopathological features. Methods: A total of 180 patients were included: 120 with HCC on top of LC (60 with either early or late HCC) and 60 patients with HCV-related LC. In addition, 60 healthy individuals were considered as controls. Real-time polymerase chain reactions were performed for expression profiling of serum miR-34a and Hsp70 and for allelic discrimination of the promotor variant (rs2763979, C/T). In addition, in silico analysis was carried out. Results: All participants were heterozygote for the promotor polymorphism. miR-34a serum levels were significantly under-expressed in LC and especially HCC patients as compared to controls. Associations with a high Child-Turcotte- Pugh (CTP) score, advanced cancer stage, and number of masses were noted. In contrast the target Hsp70 was significantly overexpressed in cancer patients but not in LC group and inversely correlated with miR-34a levels. Conclusion: Utility of circulating miRNAs as biomarkers for early detection of HCC was raised. Future large-scale studies are warranted to confirm the current findings.

Elevated serum heat shock protein 70 and liver stiffness reflect hepatic dysfunction and severity in postoperative biliary atresia

BACKGROUND

Biliary atresia (BA) is a severe chronic liver disease characterized by progressive obstructive cholangiopathy of biliary tract. Heat shock protein 70 (HSP70) is involved in protecting cells against a wide variety of stress and plays a protective role in tissue damage. The purpose of this study was to investigate serum HSP70 and liver stiffness in BA and determine the association of serum HSP70, liver stiffness, and outcome parameters in post-Kasai BA patients.

METHODS

One hundred post-Kasai BA patients and 40 controls were enrolled. Serum HSP70 levels were analyzed using enzyme-linked immunosorbent assay. Liver stiffness values were assessed by transient elastography.

RESULTS

BA patients had significantly higher serum HSP70 and liver stiffness values than controls. Serum HSP70 and liver stiffness values were markedly elevated in BA patients with jaundice compared to those without jaundice (P < 0.001). Furthermore, serum HSP70 was more elevated in BA children with portal hypertension than those without portal hypertension (35.1 ± 2.1 vs. 27.9 ± 2.5 ng/mL, P < 0.001). Moreover, serum HSP70 was positively correlated with serum aspartate aminotransferase (r = 0.491, P < 0.001), alanine aminotransferase (r = 0.448, P < 0.001), total bilirubin (r = 0.303, P = 0.002), alkaline phosphatase (r = 0.414, P < 0.001), and liver stiffness values (r = 0.455, P < 0.001). There was a negative correlation between serum HSP70 and serum albumin (r = -0.434, P = 0.001).

CONCLUSION

Serum HSP70 and liver stiffness values were higher in BA patients than controls. The increased serum HSP70 was correlated with hepatic dysfunction in BA. Consequently, serum HSP70 and liver stiffness could serve as non-invasive parameters reflecting the severity in post-Kasai BA.

Combined use of heat-shock protein 70 and glutamine synthetase is useful in the distinction of typical hepatocellular adenoma from atypical hepatocellular neoplasms and well-differentiated hepatocellular carcinoma

Well-differentiated hepatocellular carcinoma can mimic high-grade dysplastic nodule in cirrhotic liver and hepatocellular adenoma in non-cirrhotic liver. This study evaluates the efficacy of combined use of heat-shock protein 70 (HSP70), glutamine synthetase (GS) and glypican-3 in this setting. Immunohistochemistry for these three markers was done in 17 typical hepatocellular adenoma, 15 high-grade dysplastic nodules, 20 atypical hepatocellular neoplasms (14 clinically atypical and 6 pathologically atypical), 14 very well-differentiated hepatocellular carcinoma, and 43 well-differentiated hepatocellular carcinoma. All three markers were negative in typical adenomas. HSP70 was positive in 10, 71, and 67% of atypical neoplasms, very well-differentiated and well-differentiated HCC, respectively, while GS was positive in 60, 50, and 60% of atypical neoplasms, very well-differentiated and well-differentiated hepatocellular carcinoma, respectively. Glypican-3 was negative in all atypical neoplasms and very well-differentiated hepatocellular carcinoma, and was positive in 27% of well-differentiated hepatocellular carcinoma. Positive staining with at least one marker (HSP70 and/or GS) was seen in 85% of very well-differentiated hepatocellular carcinoma, which was similar to well-differentiated hepatocellular carcinoma (78%, P=0.4), and pathologically atypical cases (100%, P=0.5), but significantly higher compared with clinically atypical cases (43%. P=0.03) and none of typical adenomas (P<0.001). Positive staining with both GS and HSP70 was seen significantly more often in hepatocellular carcinoma compared with atypical neoplasms (45 vs 10%, P=0.004). Both these markers were also more often expressed in very well-differentiated hepatocellular carcinoma compared with atypical cases (38 vs 10%, P=0.06). In conclusion, the combined use of GS and HSP70 can be useful in the diagnosis of very well-differentiated hepatocellular carcinoma. These stains can also help in the distinction of typical adenoma from atypical hepatocellular neoplasms. Glypican-3 has low sensitivity and is not useful in this setting.

Expression of P53 and HSP70 in Chronic Hepatitis, Liver Cirrhosis, and Early and Advanced Hepatocellular Carcinoma Tissues and Their Diagnostic Value in Hepatocellular Carcinoma: An Immunohistochemical Study

Background

Tumor protein (P53) and heat shock protein 70 (HSP70) play key roles in chronic liver diseases. This study aimed to characterize P53 and HSP70 expression in chronic hepatitis (CH), liver cirrhosis (LC), early and advanced HCC, and to analyze their diagnostic value in hepatocellular carcinoma (HCC).

Material/Methods

Immunohistochemical staining was conducted to evaluate the expression of P53 and HSP70 in 200 human liver tissue specimens, with advanced HCC (n=80), early HCC (n=30), CH (n=30), LC (n=30), and Controls (n=30).

Results

P53 expression levels were lower in LC than those of HCC, but remained on par with those of CH and Controls. HSP70 expression levels were higher in HCC than those of LC, CH, and Controls. The sensitivity and specificity for HCC diagnosis were: 50.9% and 98.9% for P53, and 78.2 and 77.8% for HSP70, respectively. The sensitivity and specificity of different combinations were: 95.5% and 85.5% with either P53 or HSP70 being positive, and 33.6% and 98.9% if both were positive. Among the differentiation stages marked low, intermediate, and high in HCC, the P53 positive rate was higher in the low than in the intermediate, which was higher than that in the high. HSP70 positive rate was higher in the low and the intermediate than in the high, but no obvious changes were found between the low and the intermediate.

Conclusions

P53 and HSP70 could be potential biomarkers for HCC diagnosis, and proper combinations of these 2 markers could improve diagnostic accuracy.

Heat shock proteins in hepatocellular carcinoma: Molecular mechanism and therapeutic potential

Heat shock proteins (HSPs) are highly conserved proteins, which are expressed at low levels under normal conditions, but significantly induced in response to cellular stresses. As molecular chaperones, HSPs play crucial roles in protein homeostasis, apoptosis, invasion and cellular signaling transduction. The induction of HSPs is an important part of heat shock response, which could help cancer cells to adapt to stress conditions. Because of the constant stress condition in tumor microenvironment, HSPs overexpression is widely reported in many human cancers. In light of the significance of HSPs for cancer cells to survive and obtain invasive phenotype under stress condition, HSPs are often associated with poor prognosis and treatment resistance in many types of human cancers. It has been described that upregulation of HSPs may serve as diagnostic and prognostic markers in hepatocellular carcinoma (HCC). Targeting HSPs with specific inhibitor alone or in combination with chemotherapy regimens holds promise for the improvement of outcomes for HCC patients. In this review, we summarize the expression profiles, functions and molecular mechanisms of HSPs (HSP27, HSP70 and HSP90) as well as a HSP-like protein (clusterin) in HCC. In addition, we address progression and challenges in targeting these HSPs as novel therapeutic strategies in HCC.

Hsp70 in cancer: back to the future

Mechanistic studies from cell culture and animal models have revealed critical roles for the heat shock protein Hsp70 in cancer initiation and progression. Surprisingly, many effects of Hsp70 on cancer have not been related to its chaperone activity, but rather to its role(s) in regulating cell signaling. A major factor that directs Hsp70 signaling activity appears to be the co-chaperone Bag3. Here, we review these recent breakthroughs, and how these discoveries drive drug development efforts.

Hepatic expression of the Sptlc3 subunit of serine palmitoyltransferase is associated with the development of hepatocellular carcinoma in a mouse model of nonalcoholic steatohepatitis

The molecular mechanisms underlying the progression of nonalcoholic steatohepatitis (NASH) have not been fully elucidated. The aim of this study was to identify factors involved in NASH progression by analysis of pathophysiological features and gene-expression profiles in livers of STAM mice, a model of NASH-associated hepatocarcinogenesis. C57BL/6N (B6N) mice were injected with streptozotocin to generate STAM mice. Four-week-old male STAM and B6N mice were fed a high-fat diet (HFD) (STAM-F, B6N-F) or a conventional diet (STAM-C, B6N-C) until they were 10, 14, or 18 weeks old. Blood glucose and nonalcoholic fatty liver disease (NAFLD) activity scores of STAM-F were higher than those of STAM-C during all observation periods. STAM-F mice had more severe hepatic fibrosis at 14 weeks, and exhibited higher levels of α-fetoprotein-positive hepatic tumor formation with multiplication than STAM-C mice at 18 weeks. At 14 weeks, cDNA microarray analysis revealed that the hepatic expression of eight mRNAs was ≥30-fold higher in STAM-F than B6N-F mice. The expression of another four genes was increased ≥5-fold in STAM-F than B6N-F mice, and ≥5-fold in B6N-F relative to B6N-C mice. Of the 12 genes, the difference in Sptlc3 mRNA expression was most pronounced, and gradually increased over time, as determined by quantitative RT-PCR in STAM-F mice. In addition, Sptlc3 mRNA expression in STAM-F mice was higher than that in db/db mice that received HFD and in B6N mice fed a choline‑deficient L-amino acid (CDAA)-defined diet. In conclusion, a high-fat diet aggravated pathophysiological findings in the liver in NASH mouse models, and the hepatic expression of Sptlc3 mRNA was potentially associated with NASH progression.

Novel proteomic biomarker panel for prediction of aggressive metastatic hepatocellular carcinoma relapse in surgically resectable patients

The natural course of early HCC is unknown, and its progression to intermediate and advanced HCC can be diverse. Some early stage HCC patients enjoy prolonged disease-free survival, whereas others suffer aggressive relapse to stage IV metastatic cancer within a year. Comparative proteomics of HCC tumor tissues was carried out using 2D-DIGE and MALDI-TOF/TOF MS to identify proteins that can distinguish these two groups of stage I HCC patients. Twelve out of 148 differentially regulated protein spots were found to differ by approximately 2-fold for the relapse versus nonrelapse patient tissues. Four proteins, namely, heat shock 70 kDa protein 1, argininosuccinate synthase, isoform 2 of UTP-glucose-1-phosphate uridylyltransferase, and transketolase, were shown to have the potential to differentiate metastatic relapse (MR) from nonrelapse (NR) HCC patients after validation by western blotting and immunohistochemical assays. Subsequent TMA analysis revealed a three marker panel of HSP70, ASS1, and UGP2 to be statistically significant in stratifying the two groups of HCC patients. This combination panel achieved high levels of sensitivity and specificity, which has potential for clinical use in identifying HCC tumors prone to MR. This stratification will allow development of clinical management, including close follow-up and possibly treatment options, in the near future.

14-3-3σ induces heat shock protein 70 expression in hepatocellular carcinoma

Background

14-3-3σ is implicated in promoting tumor development of various malignancies. However, the clinical relevance of 14-3-3σ in hepatocellular carcinoma (HCC) tumor progression and modulation and pathway elucidation remain unclear.

Methods

We investigated 14-3-3σ expression in 109 HCC tissues by immunohistochemistry. Overexpression and knockdown experiments were performed by transfection with cDNA or siRNA. Protein expression and cell migration were determined by Western blot and Boyden chamber assay.

Results

In this study, we found that 14-3-3σ is abundantly expressed in HCC tumors. Stable or transient overexpression of 14-3-3σ induces the expression of heat shock factor-1α (HSF-1α) and heat shock protein 70 (HSP70) in HCC cells. Moreover, expression of 14-3-3σ significantly correlates with HSF-1α/HSP70 in HCC tumors and both 14-3-3σ and HSP70 overexpression are associated with micro-vascular thrombi in HCC patients, suggesting that 14-3-3σ/HSP70 expression is potentially involved in cell migration/invasion. Results of an in vitro migration assay indicate that 14-3-3σ promotes cell migration and that 14-3-3σ-induced cell migration is impaired by siRNA knockdown of HSP70. Finally, 14-3-3σ-induced HSF-1α/HSP70 expression is abolished by the knockdown of β-catenin or activation of GSK-3β.

Conclusions

Our findings indicate that 14-3-3σ participates in promoting HCC cell migration and tumor development via β-catenin/HSF-1α/HSP70 pathway regulation. Thus, 14-3-3σ alone or combined with HSP70 are potential prognostic biomarkers for HCC.

Diagnostic Approach to Hepatic Mass Lesions and Role of Immunohistochemistry

This review provides an overview of various hepatic mass lesions and a practical diagnostic approach, including most recent immunohistochemical stains used in clinical practice. A wide variety of benign and malignant lesions present as hepatic masses, and the differential diagnosis varies. In cirrhotic liver, the commonest malignant tumor is hepatocellular carcinoma (HCC), which needs to be differentiated from macroregenerative nodules, dysplastic nodules, and other tumors. The differential diagnosis of lesions in noncirrhotic liver in younger patients includes hepatic adenoma (HA), focal nodular hyperplasia (FNH), HCC, and other primary hepatic neoplasms and metastases. In older populations, metastases remain the most common mass lesions.

Tumor markers for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with a high rate of morbidity and mortality. HCC affects approximately one million individuals annually worldwide, with the incidence equal to the mortality rate. In 2008, HCC was listed as the third most lethal cancer. Thus, early diagnosis is crucial for improving the survival rate for patients. α-fetoprotein (AFP) together with iconography and pathology detection are commonly used in the clinical early diagnosis of liver cancer. However, the specificity and sensitivity of AFP used in screening for liver cancer are not satisfactory. Athough the development of molecular biology has led to the identification of new tumor markers, including proteantigens, cytokines, enzymes and isoenzymes, as well as related genes that can be used in the treatment and prognosis of liver cancer, more tumor markers are required for effective early diagnosis of diseases and monitoring of the curative effect.