Targeting of HSP70/HSF1 Axis Abrogates In Vitro Ibrutinib-Resistance in Chronic Lymphocytic Leukemia

Heat Shock Proteins, a Double-Edged Sword: Significance in Cancer Progression, Chemotherapy Resistance and Novel Therapeutic Perspectives

Heat shock proteins (Hsps) are involved in one of the adaptive mechanisms protecting cells against environmental and metabolic stress. Moreover, the large role of these proteins in the carcinogenesis process, as well as in chemoresistance, was noticed. This review aims to draw attention to the possibilities of using Hsps in developing new cancer therapy methods, as well as to indicate directions for future research on this topic. In order to discuss this matter, a thorough review of the latest scientific literature was carried out, taking into account the importance of selected proteins from the Hsp family, including Hsp27, Hsp40, Hsp60, Hsp70, Hsp90 and Hsp110. One of the more characteristic features of all Hsps is that they play a multifaceted role in cancer progression, which makes them an obvious target for modern anticancer therapy. Some researchers emphasize the importance of directly inhibiting the action of these proteins. In turn, others point to their possible use in the design of cancer vaccines, which would work by inducing an immune response in various types of cancer. Due to these possibilities, it is believed that the use of Hsps may contribute to the progress of oncoimmunology, and thus help in the development of modern anticancer therapies, which would be characterized by higher effectiveness and lower toxicity to the patients.

How receptor tyrosine kinase-like orphan receptor 1 meets its partners in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most common leukemia in western societies, recognized by clinical and molecular heterogeneity. Despite the success of targeted therapies, acquired resistance remains a challenge for relapsed and refractory CLL, as a consequence of mutations in the target or the upregulation of other survival pathways leading to the progression of the disease. Research on proteins that can trigger such pathways may define novel therapies for a successful outcome in CLL such as the receptor tyrosine kinase-like orphan receptor 1 (ROR1). ROR1 is a signaling receptor for Wnt5a, with an important role during embryogenesis. The aberrant expression on CLL cells and several types of tumors, is involved in cell proliferation, survival, migration as well as drug resistance. Antibody-based immunotherapies and small-molecule compounds emerged to target ROR1 in preclinical and clinical studies. Efforts have been made to identify new prognostic markers having predictive value to refine and increase the detection and management of CLL. ROR1 can be considered as an attractive target for CLL diagnosis, prognosis, and treatment. It can be clinically effective alone and/or in combination with current approved agents. In this review, we summarize the scientific achievements in targeting ROR1 for CLL diagnosis, prognosis, and treatment.

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.

Focal adhesion kinase activation by calcium-dependent calpain is involved in chronic lymphocytic leukaemia cell aggressiveness

Signalling events downstream the B-cell receptor (BCR) are central for the survival and progression of chronic lymphocytic leukaemia (CLL) cells. Focal adhesion kinase (FAK), regulated through calpain, interacts with molecules of BCR signalling, cytoskeletal modelling and disease progression, such as Src/Lyn, cortactin and HS1. Hypothesizing that FAK might play a key role in CLL pathogenesis, we observed a down-modulation of FAK whole form, associated with FAK cleavage due to calpain activity upon BCR stimulation. Patients, whose cells were able to release Ca++ after BCR stimulation, had less amount of full-length FAK, which translated into a higher presence of cleaved/activated form of the protein phosphorylated at Y397, these features being mostly shown by immunoglobulin heavy chain (IGHV)-unmutated poor-prognosis patients. Moreover, we found that cortactin and HS1 proteins were overexpressed in those cells, suggesting a possible interplay with FAK. Treatment with the FAK inhibitor Defactinib was able to induce apoptosis in CLL cells. In conclusion, the malignant phenotype in unfavourable-prognosis patients seems to be encouraged by the overexpression of cortactin and HS1, that, together with FAK, may be involved in a druggable pathogenetic pathway in CLL.

Is It Still Possible to Think about HSP70 as a Therapeutic Target in Onco-Hematological Diseases?

The search for molecules to be targeted that are involved in apoptosis resistance/increased survival and pathogenesis of onco-hematological malignancies is ongoing since these diseases are still not completely understood. Over the years, a good candidate has been identified in the Heat Shock Protein of 70kDa (HSP70), a molecule defined as “the most cytoprotective protein ever been described”. HSP70 is induced in response to a wide variety of physiological and environmental insults, allowing cells to survive lethal conditions. This molecular chaperone has been detected and studied in almost all the onco-hematological diseases and is also correlated to poor prognosis and resistance to therapy. In this review, we give an overview of the discoveries that have led us to consider HSP70 as a therapeutic target for mono- or combination-therapies in acute and chronic leukemias, multiple myeloma and different types of lymphomas. In this excursus, we will also consider HSP70 partners, such as its transcription factor HSF1 or its co-chaperones whose druggability could indirectly affect HSP70. Finally, we will try to answer the question asked in the title of this review considering that, despite the effort made by research in this field, HSP70 inhibitors never reached the clinic.

Heat-Shock Proteins in Leukemia and Lymphoma: Multitargets for Innovative Therapeutic Approaches

Heat-shock proteins (HSPs) are powerful chaperones that provide support for cellular functions under stress conditions but also for the homeostasis of basic cellular machinery. All cancer cells strongly rely on HSPs, as they must continuously adapt to internal but also microenvironmental stresses to survive. In solid tumors, HSPs have been described as helping to correct the folding of misfolded proteins, sustain oncogenic pathways, and prevent apoptosis. Leukemias and lymphomas also overexpress HSPs, which are frequently associated with resistance to therapy. HSPs have therefore been proposed as new therapeutic targets. Given the specific biology of hematological malignancies, it is essential to revise their role in this field, providing a more adaptable and comprehensive picture that would help design future clinical trials. To that end, this review will describe the different pathways and functions regulated by HSP27, HSP70, HSP90, and, not least, HSP110 in leukemias and lymphomas.

Hsp27, Hsp60, Hsp70, or Hsp90 depletion enhances the antitumor effects of resveratrol via oxidative and ER stress response in human glioblastoma cells

Therapeutic resistance of gliomas is still a crucial issue and closely related to induced heat shock response (HSR). Resveratrol (RSV) is a promising experimental agent for glioblastoma (GB) therapy. However, the role of heat shock protein (Hsp)27, Hsp60, Hsp70, and Hsp90 on the therapeutic efficacy of RSV remains unclear in gliomas. Herein, small interfering (si)RNA transfection was performed to block Hsp expressions. RSV treatments reduced glioma cells' viability dose- and time-dependent while keeping HEK-293 normal cells alive. Furthermore, a low dose of RSV (15 µM/48 h) offered protection against oxidative stress and apoptosis due to Hsp depletion in healthy cells. On the contrary, in glioma cells, RSV (15 µM/48 h) increased ROS (reactive oxygen species) production, led to autophagy and induced endoplasmic reticulum (ER) stress and apoptosis, and reduced 2D- and 3D-clonogenic survival. Hsp27, Hsp60, Hsp70, or Hsp90 depletion also resulted in cell death through ER stress response and ROS burst. Remarkably, the heat shock response (increased HSF1 levels) due to Hsp depletion was attenuated by RSV in glioma cells. Collectively, our data show that these Hsp silencings make glioma cells more sensitive to RSV treatment, indicating that these Hsps are potential therapeutic targets for GB treatment.