Potential predictive value of plasma heat shock protein 90α in lung cancer

Extracellular heat shock protein 90 alpha (eHsp90α)'s role in cancer progression and the development of therapeutic strategies

Heat shock protein 90 alpha (Hsp90α) is an abundantly expressed and evolutionarily conserved molecular chaperone. Hsp90α is the inducible Hsp90 isoform, and its expression and secretion extracellularly (eHsp90α) can be triggered in response to a variety of cellular stresses to protect/activate client proteins and to facilitate cellular adjustment to the stress. As a result, cancers often have high expression levels of intracellular and extracellular (plasma) Hsp90α, allowing them to support their oncogenesis and progression. In fact, (e)Hsp90α has been implicated in regulating processes such as cell signaling transduction, DNA repair, promotion of the Epithelial-to-Mesenchymal Transition (EMT), promotion of angiogenesis, immune response, and cell migration. Hsp90α levels have been correlated with cancer progression and severity in several cancers, indicating that it may be a useful biomarker or drug-target for cancer. To date, the development of intracellular Hsp90α-targeted therapies include standard N-terminal ATP-competitive inhibitors and allosteric regulators that bind to Hsp90α's middle or C-terminal domain. On-target toxicities and dosing complications as a result of Hsp90α inhibition has driven the development of eHsp90α-targeted therapies. Examples include anti-Hsp90α monoclonal antibodies and cell-impermeable Hsp90α small molecule inhibitors. This review aims to discuss the many roles Hsp90α plays in cancer progression with a focus on the current development of Hsp90α-targeted therapies.

Hsp90α and cell death in cancers: a review

Heat shock protein 90α (Hsp90α), an important molecular chaperone, plays a crucial role in regulating the activity of various intracellular signaling pathways and maintaining the stability of various signaling transduction proteins. In cancer, the expression level of Hsp90α is often significantly upregulated and is recognized as one of the key factors in cancer cell survival and proliferation. Cell death can help achieve numerous purposes, such as preventing aging, removing damaged or infected cells, facilitating embryonic development and tissue repair, and modulating immune response. The expression of Hsp90α is closely associated with specific modes of cell death including apoptosis, necrotic apoptosis, and autophagy-dependent cell death, etc. This review discusses the new results on the relationship between expression of Hsp90α and cell death in cancer. Hsp90α is frequently overexpressed in cancer and promotes cancer cell growth, survival, and resistance to treatment by regulating cell death, rendering it a promising target for cancer therapy.

Predictive Value of Serum Heat Shock Protein 90α on the Prognosis of Patients with Lung Adenocarcinoma

Purpose

Heat shock protein 90α (HSP90α) is highly expressed in tumors, and predicts tumor progression. This study analyzed the correlation between the expression level of HSP90α in the serum and the prognosis of patients with lung adenocarcinoma.

Patients and methods

The medical records of patients with 228 lung adenocarcinoma from September 2015 to December 2021 were analyzed. HSP90α expression in the patients' serum was detected by ELISA and the cut-off value (93.76 ng/mL) was determined according to the ROC curve, then the patients were divided into high- and low-level groups. The differences in the medical records of the two groups were compared using the X² test, and Univariate and multivariate Cox regression analyses showed that serum HSP90α level were independent risk factors for both PFS and OS (P < 0.05).

Results

HSP90α was positively correlated with TNM staging (P < 0.01) by One-way analysis of variance. The results of the correlation analysis and the Kaplan-Meier survival curve showed that the expression levels of HSP90α and CEA of patients were positively correlated (R=0.54, P < 0.001), and patients with high HSP90α and CEA levels had the worst OS (P < 0.001).

Conclusion

HSP90α expression is negatively correlated with the prognosis of patients with lung adenocarcinoma and is a potential prognostic marker.

HSP90 mediates the connection of multiple programmed cell death in diseases

Heat shock protein (HSP) 90, an important component of the molecular chaperone network, is closely concerned with cellular signaling pathways and stress response by participating in the process of maturation and activation of client proteins, playing a crucial role both in the normal and abnormal operation of the organism. In functionally defective tissues, programmed cell death (PCD) is one of the regulable fundamental mechanisms mediated by HSP90, including apoptosis, autophagy, necroptosis, ferroptosis, and others. Here, we show the complex relationship between HSP90 and different types of PCD in various diseases, and discuss the possibility of HSP90 as the common regulatory nodal in multiple PCD, which would provide a new perspective for the therapeutic approaches in disease.

Heat-shock protein 90α is a potential prognostic and predictive biomarker in hepatocellular carcinoma: a large-scale and multicenter study

BACKGROUND

Although the diagnostic value of plasma heat-shock protein 90α (HSP90α) in hepatocellular carcinoma (HCC) has been previously reported, the causal effect of the plasma HSP90α levels on HCC prognosis remains largely unclear. To this extent, we sought to assess whether the plasma HSP90α acts as a prognostic factor for HCC patients.

METHODS

A total of 2150 HCC patients were included in this retrospective study between August 2016 and July 2021. Plasma HSP90α levels were tested within a week before treatment and their association with prognosis was assessed.

RESULTS

An optimal cutoff value of 143.5 for the HSP90α based on the overall survival (OS) was determined using the X-tile software. HCC patients with HSP90α < 143.5 ng/mL (low HSP90α) before and after propensity score matching (PSM) indicated longer median OS (mOS) relative to those with HSP90α ≥ 143.5 ng/mL (high HSP90α) (37.0 vs. 9.0 months, p < 0.001; 19.2 vs. 9.6 months, p < 0.001; respectively). In addition, the high HSP90α plasma level is an independent poor prognostic factor for OS in HCC patients. In our subgroup analysis, including the supportive care group, surgery group, transarterial chemoembolization (TACE) group, adjuvant TACE group, an immune checkpoint inhibitor (ICI) plus targeted therapy group, and TACE plus ICI group, the high HSP90α group demonstrated better OS compared to the low HSP90α group. Moreover, in the supportive care, TACE, ICI plus targeted therapy, TACE plus ICI groups, and high HSP90α levels were also an independent poor prognostic factors for OS.

CONCLUSIONS

Our study confirmed that the plasma HSP90α level can be used as a prognostic biomarker for HCC.

Analysis of the prognostic, diagnostic and immunological role of HSP90α in malignant tumors

Heat shock protein 90α (HSP90α) encoded by the HSP90AA1 gene, is the stress inducible isoform of the molecular chaperone HSP90, and was demonstrated as a promising hallmark to diagnose, prognosis in malignant tumors. This study is to evaluate the value of HSP90α in diagnosis, prognosis and immunotherapy of malignant tumors by investigating the expression of HSP90α in plasma of various tumors and analyzing the expression of HSP90α at gene and protein levels via pan-cancer database. We founded that levels of HSP90α in malignant tumors groups were significantly higher than healthy controls in serum. Pan-cancer analysis showed that HSP90AA1 was highly expressed in 27 of 33 tumors, but low in individual cancers (such as renal malignancies). The plasma HSP90α level was positively correlated with the stage of malignant tumor, but there was no significant difference between HSP90AA1 and the stage of most tumors. Cox regression analysis showed that HSP90AA1 expression was significantly correlated with OS in only 6 of the 32 cancers, including LIHC, KIRC, HNSC, LUAD, BRCA and MESO. Up-regulation of HSP90AA1 in most tumors was positively correlated with PDCD1LG2 and CD274 immune checkpoint genes. T cell CD8+ was positively correlated with HSP90AA1 in COAD, DLBC and UVM, and negatively correlated with HSP90AA1 in ESCA, GBM, HNSC, KIRC, KIRP, UCEC and STAD. The AUC of HSP90α are generally high in different tumor groups, which indicated its diagnostic value in malignant tumors. In conclusion, serum HSP90α in patients with malignant tumor is generally elevated, which is of positive significance as an independent diagnosis and combined diagnosis. However, we found that the expression level of HSP90AA1 gene in most tumors was not completely consistent with the serum level, and even down-regulated in some tumors. Plasma levels can be used as biomarkers of poor prognosis in some tumors, but it cannot be used as a biomarker for poor prognosis of all tumors, and more in-depth studies are needed.