Structure prediction, expression, and antigenicity of c-terminal of GRP78

Introduction of a new recombinant vaccine based on GRP78 for breast cancer immunotherapy and evaluation in a mouse model

Introduction

Breast cancer is one of the most prevalent malignancies in women. Several treatment options are available today, including surgery, chemotherapy, and radiotherapy. Immunotherapy, as a highly specific therapy, involves adaptive immune responses and immunological memory. In our present research, we used the recombinant C-terminal domain of the GRP78 (glucose- regulated protein 78) protein to induce an immune response and investigate its therapeutic impact in the 4T1 breast cancer model.

Methods

BALB/c mice were immunized with the cGRP78 protein. The humoral immune response was assessed by ELISA. Then, BALB/c mice were injected subcutaneously with 1×106 4T1 tumor cells. Subsequently, tumor size and survival rate measurements, MTT, and cytokine assays were performed.

Results

The animals receiving the cGRP78 vaccine showed significantly more favorable survival and slower tumor growth rates compared with unvaccinated tumor-bearing mice as the negative control mice. Circulating levels of tumoricidal cytokines such as IFNγ were higher, whereas tolerogenic cytokines such as IL-2, 6, and 10 either did not increase or had a decreasing trend in mice receiving cGRP78.

Conclusion

cGRP78 vaccines generated potent immunotherapeutic effects in a breast cancer mouse model. This novel strategy of targeting the GRP78 protein can promote the development of cancer vaccines and immunotherapies for breast cancer malignancies.

Physiological Roles of the Autoantibodies to the 78-Kilodalton Glucose-Regulated Protein (GRP78) in Cancer and Autoimmune Diseases

The 78 kDa glucose-regulated protein (GRP78), a member of the 70 kDa heat-shock family of molecular chaperones (HSP70), is essential for the regulation of the unfolded protein response (UPR) resulting from cellular endoplasmic reticulum (ER) stress. During ER stress, GRP78 evades retention mechanisms and is translocated to the cell surface (csGRP78) where it functions as an autoantigen. Autoantibodies to GRP78 appear in prostate, ovarian, gastric, malignant melanoma, and colorectal cancers. They are also found in autoimmune pathologies such as rheumatoid arthritis (RA), neuromyelitis optica (NMO), anti-myelin oligodendrocyte glycoprotein antibody-associated disorder (AMOGAD), Lambert-Eaton myasthenic syndrome (LEMS), multiple sclerosis (MS), neuropsychiatric systemic lupus erythematosus (NPSLE) and type 1 diabetes (T1D). In NMO, MS, and NPSLE these autoantibodies disrupt and move across the blood-brain barrier (BBB), facilitating their entry and that of other pathogenic antibodies to the brain. Although csGRP78 is common in both cancer and autoimmune diseases, there are major differences in the specificity of its autoantibodies. Here, we discuss how ER mechanisms modulate csGRP78 antigenicity and the production of autoantibodies, permitting this chaperone to function as a dual compartmentalized receptor with independent signaling pathways that promote either pro-proliferative or apoptotic signaling, depending on whether the autoantibodies bind csGRP78 N- or C-terminal regions.

Isolation and characterization of a novel GRP78-specific single-chain variable fragment (scFv) using ribosome display method

Glucose-regulated protein 78 (GRP78) is a well-characterized endoplasmic reticulum (ER) chaperon frequently overexpressed at the surface of tumor cells and associated with tumor survival, metastasis, and chemoresistance. Hence, potential GRP78 binders emerge as promising candidates for cancer therapy and diagnosis. We applied ribosome display to isolate a single-chain variable domain (scFv) specific for the C-terminal domain of a recombinant human GRP78 (CGRP). Six female BALB/c mice were immunized and then splenocyte mRNA was extracted. An scFv-ribosome display library was established by joining the amplified V_H/Vκ fragments through a 72-bp linker using overlap extension PCR. Then, selection was performed by applying two rounds of eukaryotic ribosome display panning with stepwise decreased amount of CGRP. Ultimately, the selected scFv was characterized using the indirect-ELISA assay, competitive-ELISA assay, Western blotting, Surface Plasmon Resonance (SPR), and in-silico analyses. The constructed library had a length of ~ 1100 bp and the high-affinity scFvs were isolated using the outputs of the final panning round. Among 60 positive clones, GSF3 was selected and its expression, purification, and binding capacity was confirmed by SDS-PAGE and Western blotting. GSF3 exhibited an affinity of 13 × 10⁷ M^-1 to CGRP as assessed by SPR. Moreover, the in-silico analyses indicated that GSF3 binds the C-terminal domain of GRP78 through key residues engaged in antibody-antigen interactions. We found that ribosome display is a swift and reliable technique for specific and high-affinity scFv isolation. Moreover, our results suggest that GSF3 might be applied as a potential cancer immunotherapeutic and diagnostic tool if this approach is carefully followed by successful preclinical and clinical evaluations to validate the findings for further confirmation.

Integrative role of traditional and modern technologies to combat COVID-19

INTRODUCTION

With the development of various branches of sciences, we will be able to resolve different clinical aspects of various diseases better. The convergence of these sciences can potentially tackle the new corona crisis.

AREAS COVERED

In this review, we attempted to explore and describe various scientific branches studying COVID-19. We have reviewed the literature focusing on the prevention, diagnosis, and treatment of COVID-19. The primary databases targeted were Science Direct, Scopus and PubMed. The most relevant reports from the recent two decades were collected utilizing keywords including SARS-CoV, MERS-CoV, COVID-19, epidemiology, therapeutics and diagnosis.

EXPERT OPINION

Based on this literature review, both traditional and emerging approaches are vital for the prevention, diagnosis and treatment of COVID-19. The traditional sciences play an essential role in the preventive and supportive care of corona infection, and modern technologies appear to be useful in the development of precise diagnosis and powerful treatment approaches for this disease. Indeed, the integration of these sciences will help us to fight COVID-19 disease more efficiently.

Isolation and characterization of a novel nanobody for detection of GRP78 expressing cancer cells

Glucose-regulated protein 78 (GRP78) is an endoplasmic reticulum (ER) chaperone that has been shown that is overexpressed in cancer cells. Overexpression of GRP78 on cancer cells makes this molecule a suitable candidate for cancer detection and targeted therapy. VHH is the binding fragment of camelid heavy-chain antibodies also known as "nanobody." The aim of this study is to isolate and produce a new recombinant nanobody using phage display technique to detect cancer cells. Using the c-terminal domain of GRP78 (CGRP) as an antigen, four rounds of biopanning were performed, and high-affinity binders were selected by ELISA. Their affinity and functionality were characterized by surface plasmon resonance (SPR) cell ELISA and immunocytochemistry. A unique nanobody named V80 was purified. ELISA and SPR showed that this antibody had high specificity and affinity to the GRP78. Immunofluorescence analysis showed that V80 could specifically bind to the HepG2 and A549 cancer cell lines. This novel recombinant nanobody could bind to the cell surface of different cancer cells. After further evaluation, this nanobody can be used as a new tool for cancer detection and tumor therapy.

Ablation of PKM2 ameliorated ER stress-induced apoptosis and associated inflammation response in IL-1β-treated chondrocytes via blocking Rspo2-mediated Wnt/β-catenin signaling

Endoplasmic reticulum (ER) stress and the related apoptosis and inflammation damage play key roles in osteoarthritis development. The aim of the present work was to investigate the exact role and potential underlying mechanism of pyruvate kinase M2 (PKM2) in rat chondrocytes exposed to interleukin-Iβ (IL-1β). We observed that IL-1β stimulation resulted in an apparent enhancement in PKM2 expression. Additionally, loss of PKM2 evidently ascended cell viability in response to IL-1β exposure. Simultaneously, elimination of PKM2 manifestly repressed IL-1β-stimulated chondrocyte apoptosis, concomitant with attenuated in the proapoptotic protein markers Bax and cleaved caspase-3, and elevated the antiapoptotic protein Bcl-2. In the meanwhile, knockdown of PKM2 ameliorated ER stress in IL-1β-treated chondrocytes, as evidenced by reduced expression of the ER stress-associated proteins GRP78, CHOP, and cleaved caspase-12. Furthermore, PKM2 silencing protected chondrocytes against IL-1β-triggered inflammatory response, as reflected by the downregulated release of proinflammatory mediators, including tumor necrosis factor-α, IL-6, inducible nitric oxide synthase, cyclooxygenase-2, and prostaglandin E2, as well as decreased nitric oxide generation. More important, abrogating PKM2 expression caused a marked decline in Rspo2 expression, and subsequently blocked Wnt/β-catenin signaling. Mechanistically, the Wnt/β-catenin signaling activator Licl effectively impeded the beneficial effects of PKM2 ablation on IL-1β-stimulated apoptosis and inflammatory response. These findings collectively implicated that PKM2 inhibition protected against ER stress-mediated cell apoptosis and inflammatory injury in rat chondrocytes stimulated with IL-1β by inactivating Rspo2-mediated Wnt/β-catenin pathway, and may represented a novel therapeutic target for osteoarthritis.

Comparative detection method of early onset cytokine-induced stress in β-cells (INS-1E)

β-Cells contain a prominent endoplasmic reticulum (ER), disrupting ER homeostasis and function, activating the unfolded protein response (UPR). Currently, no direct protocols measure the UPR initiation. Current methods to measure ER stress include the quantification of nitric oxide (NO) (indirect method), Western blotting, and qRT-PCR of downstream components. However, these methods do not account for the overlap with mitochondrial dysfunction. In this study, INS-1E cells were exposed to proinflammatory cytokines to induce ER stress, as determined using NO, thioflavin T (ThT) binding, and β-cell functionality (insulin production). ER stress was confirmed through the upregulation of CHOP. Cell viability was monitored using MTT, sulforhodamine B, and the xCELLigence system. Morphological changes were monitored using electron microscopy. IL-1β exposure-induced β-cell stress after 4 H, decreased insulin levels, and increased thioflavin binding were noted. Increased NO production was only detected after 10 H, highlighting its lack of sensitivity, and the need for a continuous, selective, rapid, convenient, and economical detection method for early onset of ER stress. Standard methods (MTT and NO) failed to detect early ER stress. The xCELLigence coupled with a functional assay such as the detection of insulin levels or ThT are better predictors of ER stress in INS-1E cells.

4-Phenylbutyric acid presents therapeutic effect on osteoarthritis via inhibiting cell apoptosis and inflammatory response induced by endoplasmic reticulum stress

Osteoarthritis (OA) is a common bone and joint disease with a wild range of risk factors, which is associated with endoplasmic reticulum (ER) stress. The aim of our study was to discuss the possible mechanism of ER stress associated with OA in vivo and explore novel therapeutic method against OA. OA-induced damages in cartilage tissues were evaluated by HE, Safranin O/fast green, and TUNEL staining. The inflammatory factors concentration and the expression of FAP, MMP2, MMP9, Bax, Bcl-2, CHOP, and GRP78 were evaluated by ELISA, real-time PCR, and Western blot analyses. As results, 4-phenylbutyric acid (4-PBA)-treated OA cartilage tissues presented alleviated tissue damage with less apoptotic cells and cytokine production in comparison with advanced-OA tissues. Downregulation of Bax/Bcl-2, CHOP, GRP78, inflammatory factors, and reactive oxygen species generation, and the increase of MMP level detected after 4-PBA treatment indicated an inhibitory effect of 4-PBA on cell apoptosis, inflammatory response, and ER stress in OA. In conclusion, we indicate that ER stress causes cell apoptosis and inflammatory response, resulting in the tissue damage within OA. At the same time, 4-PBA exhibited protective effect on cartilage cells against OA through the inhibition of ER stress.