Plasma Hsp90 Level as a Marker of Early Acute Lymphoblastic Leukemia Engraftment and Progression in Mice

Bacterial heat shock protein genes during induction chemotherapy in pediatric patients with acute lymphoblastic leukemia

Background: Heat shock proteins (HSP) protect cancer cells. Gastrointestinal bacteria contain HSP genes and can release extracellular vesicles which act as biological shuttles. Stress from treatment may result in a microbial community with more HSP genes, which could contribute to circulating HSP levels. Methods: The authors examined the abundance of five bacterial HSP genes pre-treatment and during induction in stool sequences from 30 pediatric acute lymphoblastic leukemia patients. Results: Decreased mean HTPG counts (p = 0.0024) pre-treatment versus induction were observed. During induction, HTPG, Shannon diversity and Bacteroidetes decreased (p = 7.5e-4; 1.1e-3; 8.6e-4), while DNAK and Firmicutes increased (p = 6.9e-3; 9.2e-4). Conclusion: Understanding microbial HSP gene community changes with treatment is the first step in determining if bacterial HSPs are important to the tumor microenvironment and leukemia treatment.

Potential use of heat shock protein 90 as a biomarker for the diagnosis of human diseases

INTRODUCTION

The heat shock protein 90 (Hsp90) is a protein involved in many different biological processes and especially in cell survival. Some of these functions require the participation of other biological molecules, so Hsp90 is a chaperone that takes part in many protein-protein interactions working as a critical signaling hub protein. As a member of the heat shock protein family, Hsp90 expression is regulated under certain environmental and/or stressful situations, therefore Hsp90 concentration can be monitored and linked to these effects.

AREAS COVERED

This review discusses the Hsp90 expression in samples from individuals affected by different diseases (from infectious to cancer origin), and the biological consequences of these disorders, including the potential use of Hsp90 as a biomarker for the diagnosis of human diseases.

EXPERT OPINION

The potential of Hsp90 as a biomarker disease has been demonstrated in several studies in relation to infectious diseases and especially cancer. However, further research in this field is still needed, mainly to validate in statistically significant clinical studies that the detection of Hsp90 protein allows the diagnosis of some cancers at an early stage and also that it can act as a biomarker for monitoring the efficacy of their therapies.

HSP90 inhibitor NVP-BEP800 affects stability of SRC kinases and growth of T-cell and B-cell acute lymphoblastic leukemias

T-cell and B-cell acute lymphoblastic leukemias (T-ALL, B-ALL) are aggressive hematological malignancies characterized by an accumulation of immature T- or B-cells. Although patient outcomes have improved, novel targeted therapies are needed to reduce the intensity of chemotherapy and improve the prognosis of high-risk patients. Using cell lines, primary cells and patient-derived xenograft (PDX) models, we demonstrate that ALL cells viability is sensitive to NVP-BEP800, an ATP-competitive inhibitor of Heat shock protein 90 (HSP90). Furthermore, we reveal that lymphocyte-specific SRC family kinases (SFK) are important clients of the HSP90 chaperone in ALL. When PDX mice are treated with NVP-BEP800, we found that there is a decrease in ALL progression. Together, these results demonstrate that the chaperoning of SFK by HSP90 is involved in the growth of ALL. These novel findings provide an alternative approach to target SRC kinases and could be used for the development of new treatment strategies for ALL.

Serum heat shock protein 90 as a future predictive biomarker in childhood acute lymphoblastic leukemia

Heat shock proteins (HSPs) attract the attention of scientists and clinicians due to their potential role as diagnostic and prognostic factors in a variety of cancers. HSP90 is one of the most important and well-known family members, necessary for maintaining intracellular homeostasis. In the extracellular space, it is responsible for the transmission of alarm signals to the immune system. Numerous reports have indicated that the level of intra - and extracellular HSP90 can correlate either with a poorer prognosis or with a better outcome, depending on the type of cancer. Still, little is known why the level of this chaperone is increased in some tumors and decreased in others, reflecting dual role of protein in cell death processes. Currently, there is no database reporting levels of serum HSP90 in children with acute lymphoblastic leukemia (ALL). As such, using enzyme-linked immunosorbent assay (ELISA) method, we aimed to determine this parameter in a group of 21 patients with newly diagnosed ALL. We found decreased protein serum levels in patients at disease presentation and after induction block of chemotherapy in comparison to healthy controls. Furthermore, we observed a negative correlation between HSP90 serum levels and one of the earliest prognostic factors of the treatment response – peripheral blood lymphoblasts on the 8^th day of treatment. Our results indicate that HSP90 serum may play an important role in leukemogenesis and could be used as a marker to predict treatment failure in children with ALL.

Proteomic tools and new insights for the study of B-cell precursor acute lymphoblastic leukemia

B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is a hematological malignancy of immature B-cell precursors, affecting children more often than adults. The etiology of BCP-ALL is still unknown, but environmental factors, sex, race or ethnicity, and genomic alterations influence the development of the disease. Tools based on protein detection, such as flow cytometry, mass spectrometry, mass cytometry and reverse phase protein array, represent an opportunity to investigate BCP-ALL pathogenesis and to identify new biomarkers of disease. This review aims to document the recent advancements with respect to applications of proteomic technologies to study mechanisms of leukemogenesis, how this information could be used in the discovery of biological targets, and finally we describe the challenges of application of proteomic tools for the approach of BCP-ALL.