Virus-Receptor Interactions: Structural Insights For Oncolytic Virus Development

Small-molecule in cancer immunotherapy: Revolutionizing cancer treatment with transformative, game-changing breakthroughs

Immunotherapy has revolutionized cancer management, with antibody-based treatments leading the charge due to their superior pharmacodynamics, including enhanced effectiveness and specificity. However, these therapies are hampered by limitations such as prolonged half-lives, poor tissue and tumor penetration, and minimal oral bioavailability. Additionally, their immunogenic nature can cause adverse effects. Consequently, the focus is shifting towards small-molecule-based immunotherapies, which potentially overcome these drawbacks. Emerging as a promising alternative, small molecules offer the benefits of therapeutic antibodies and immunomodulators, often yielding synergistic effects when combined. Recent advancements in small-molecule cancer immunotherapy are notable, featuring inhibitors, agonists, and degraders that act as immunomodulators. This article delves into the current landscape of small-molecule immunotherapy in cancer treatment, highlighting novel agents targeting key pathways such as Toll-like receptors (TLR), PD-1/PD-L1, chemokine receptors, and stimulators of interferon genes (STING). The review emphasizes newly discovered molecular entities and their modulatory roles in tumorigenesis, many of which have progressed to clinical trials, that aims to provide a comprehensive snapshot of the evolving frontier in cancer treatment, driven by small-molecule immunomodulators.

Exploring treatment options in cancer: Tumor treatment strategies

Traditional therapeutic approaches such as chemotherapy and radiation therapy have burdened cancer patients with onerous physical and psychological challenges. Encouragingly, the landscape of tumor treatment has undergone a comprehensive and remarkable transformation. Emerging as fervently pursued modalities are small molecule targeted agents, antibody-drug conjugates (ADCs), cell-based therapies, and gene therapy. These cutting-edge treatment modalities not only afford personalized and precise tumor targeting, but also provide patients with enhanced therapeutic comfort and the potential to impede disease progression. Nonetheless, it is acknowledged that these therapeutic strategies still harbour untapped potential for further advancement. Gaining a comprehensive understanding of the merits and limitations of these treatment modalities holds the promise of offering novel perspectives for clinical practice and foundational research endeavours. In this review, we discussed the different treatment modalities, including small molecule targeted drugs, peptide drugs, antibody drugs, cell therapy, and gene therapy. It will provide a detailed explanation of each method, addressing their status of development, clinical challenges, and potential solutions. The aim is to assist clinicians and researchers in gaining a deeper understanding of these diverse treatment options, enabling them to carry out effective treatment and advance their research more efficiently.

Biomarker screen for efficacy of oncolytic virotherapy in patient-derived pancreatic cancer cultures

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a tumour entity with unmet medical need. To assess the therapeutic potential of oncolytic virotherapy (OVT) against PDAC, different oncolytic viruses (OVs) are currently investigated in clinical trials. However, systematic comparisons of these different OVs in terms of efficacy against PDAC and biomarkers predicting therapeutic response are lacking.

METHODS

We screened fourteen patient-derived PDAC cultures which reflect the intra- and intertumoural heterogeneity of PDAC for their sensitivity to five clinically relevant OVs, namely serotype 5 adenovirus Ad5-hTERT, herpes virus T-VEC, measles vaccine strain MV-NIS, reovirus jin-3, and protoparvovirus H-1PV. Live cell analysis, quantification of viral genome/gene expression, cell viability as well as cytotoxicity assays and titration of viral progeny were conducted. Transcriptome profiling was employed to identify potential predictive biomarkers for response to OV treatment.

FINDINGS

Patient-derived PDAC cultures showed individual response patterns to OV treatment. Twelve of fourteen cultures were responsive to at least one OV, with no single OV proving superior or inferior across all cultures. Known host factors for distinct viruses were retrieved as potential biomarkers. Compared to the classical molecular subtype, the quasi-mesenchymal or basal-like subtype of PDAC was found to be more sensitive to H-1PV, jin-3, and T-VEC. Generally, expression of viral entry receptors did not correlate with sensitivity to OV treatment, with one exception: Expression of Galectin-1 (LGALS1), a factor involved in H-1PV entry, positively correlated with H-1PV induced cell killing. Rather, cellular pathways controlling immunological, metabolic and proliferative signaling appeared to determine outcome. For instance, high baseline expression of interferon-stimulated genes (ISGs) correlated with relative resistance to oncolytic measles virus, whereas low cyclic GMP-AMP synthase (cGAS) expression was associated with exceptional response. Combination treatment of MV-NIS with a cGAS inhibitor improved tumour cell killing in several PDAC cultures and cells overexpressing cGAS were found to be less sensitive to MV oncolysis.

INTERPRETATION

Considering the heterogeneity of PDAC and the complexity of biological therapies such as OVs, no single biomarker can explain the spectrum of response patterns. For selection of a particular OV, PDAC molecular subtype, ISG expression as well as activation of distinct signaling and metabolic pathways should be considered. Combination therapies can overcome resistance in specific constellations. Overall, oncolytic virotherapy is a viable treatment option for PDAC, which warrants further development. This study highlights the need for personalised treatment in OVT. By providing all primary data, this study provides a rich source and guidance for ongoing developments.

FUNDING

German National Science Foundation (Deutsche Forschungsgemeinschaft, DFG), German Cancer Aid (Deutsche Krebshilfe), German National Academic Scholarship Foundation (Studienstiftung des deutschen Volkes), Survival with Pancreatic Cancer Foundation.

Molecular insights and promise of oncolytic virus based immunotherapy

Discovering a therapeutic that can counteract the aggressiveness of this disease's mechanism is crucial for improving survival rates for cancer patients and for better understanding the most different types of cancer. In recent years, using these viruses as an anticancer therapy has been thought to be successful. They mostly work by directly destroying cancer cells, activating the immune system to fight cancer, and expressing exogenous effector genes. For the treatment of tumors, oncolytic viruses (OVs), which can be modified to reproduce only in tumor tissues and lyse them while preserving the healthy non-neoplastic host cells and reinstating antitumor immunity which present a novel immunotherapeutic strategy. OVs can exist naturally or be created in a lab by altering existing viruses. These changes heralded the beginning of a new era of less harmful virus-based cancer therapy. We discuss three different types of oncolytic viruses that have already received regulatory approval to treat cancer as well as clinical research using oncolytic adenoviruses. The primary therapeutic applications, mechanism of action of oncolytic virus updates, future views of this therapy will be covered in this chapter.

STT3A-mediated viral N-glycosylation underlies the tumor selectivity of oncolytic virus M1

Oncolytic viruses are emerging as promising anticancer agents. Although the essential biological function of N-glycosylation on viruses are widely accepted, roles of N-glycan and glycan-processing enzyme in oncolytic viral therapy are remain elusive. Here, via cryo-EM analysis, we identified three distinct N-glycans on the envelope of oncolytic virus M1 (OVM) as being necessary for efficient receptor binding. E1-N141-glycan has immediate impact on the binding of MXRA8 receptor, E2-N200-glycan mediates the maturation of E2 from its precursor PE2 which is unable to bind with MXRA8, and E2-N262-glycan slightly promotes receptor binding. The necessity of OVM N-glycans in receptor binding make them indispensable for oncolysis in vitro and in vivo. Further investigations identified STT3A, a key catalytic subunit of oligosaccharyltransferase (OST), as the determinant of OVM N-glycosylation, and STT3A expression in tumor cells is positively correlated with OVM-induced oncolysis. Increased STT3A expression was observed in various solid tumors, pointing to a broad-spectrum anticancer potential of OVM. Collectively, our research supports the importance of STT3A-mediated N-glycosylation in receptor binding and oncolysis of OVM, thus providing a novel predictive biomarker for OVM.

Modeling of oncolytic viruses in a heterogeneous cell population to predict spread into non-cancerous cells

New cancer treatment modalities that limit patient discomfort need to be developed. One possible new therapy is the use of oncolytic (cancer-killing) viruses. It is only recently that our ability to manipulate viral genomes has allowed us to consider deliberately infecting cancer patients with viruses. One key consideration is to ensure that the virus exclusively targets cancer cells and does not harm nearby non-cancerous cells. Here, we use a mathematical model of viral infection to determine the characteristics a virus would need to have in order to eradicate a tumor, but leave non-cancerous cells untouched. We conclude that the virus must differ in its ability to infect the two different cell types, with the infection rate of non-cancerous cells needing to be less than one hundredth of the infection rate of cancer cells. Differences in viral production rate or infectious cell death rate alone are not sufficient to protect non-cancerous cells.

Oncolytic virotherapy: basic principles, recent advances and future directions

Oncolytic viruses (OVs) have attracted growing awareness in the twenty-first century, as they are generally considered to have direct oncolysis and cancer immune effects. With the progress in genetic engineering technology, OVs have been adopted as versatile platforms for developing novel antitumor strategies, used alone or in combination with other therapies. Recent studies have yielded eye-catching results that delineate the promising clinical outcomes that OVs would bring about in the future. In this review, we summarized the basic principles of OVs in terms of their classifications, as well as the recent advances in OV-modification strategies based on their characteristics, biofunctions, and cancer hallmarks. Candidate OVs are expected to be designed as "qualified soldiers" first by improving target fidelity and safety, and then equipped with "cold weapons" for a proper cytocidal effect, "hot weapons" capable of activating cancer immunotherapy, or "auxiliary weapons" by harnessing tactics such as anti-angiogenesis, reversed metabolic reprogramming and decomposing extracellular matrix around tumors. Combinations with other cancer therapeutic agents have also been elaborated to show encouraging antitumor effects. Robust results from clinical trials using OV as a treatment congruously suggested its significance in future application directions and challenges in developing OVs as novel weapons for tactical decisions in cancer treatment.

Evolving role of seneca valley virus and its biomarker TEM8/ANTXR1 in cancer therapeutics

Oncolytic viruses have made a significant inroad in cancer drug development. Numerous clinical trials are currently investigating oncolytic viruses both as single agents or in combination with various immunomodulators. Oncolytic viruses (OV) are an integral pillar of immuno-oncology and hold potential for not only delivering durable anti-tumor responses but also converting “cold” tumors to “hot” tumors. In this review we will discuss one such promising oncolytic virus called Seneca Valley Virus (SVV-001) and its therapeutic implications. SVV development has seen seismic evolution over the past decade and now boasts of being the only OV with a practically applicable biomarker for viral tropism. We discuss relevant preclinical and clinical data involving SVV and how bio-selecting for TEM8/ANTXR1, a negative tumor prognosticator can lead to first of its kind biomarker driven oncolytic viral cancer therapy.

[Oncolytic virotherapy in head and neck cancer]

OBJECTIVE

Oncolytic viruses (OV) infect and kill cancer cells and elicit an antitumoral immune response. With their potential to break through tumor immunoresistance, OV might be a future combination treatment option in patients with advanced head and neck cancer (HNC). Modes of action, biological modifications, handling and side effects of OV for treatment of HNC are reviewed. Results of preclinical and clinical trials are reported.

METHODS

Publications and clinical trials dealing with OV and HNC were searched in PubMed and international platforms for clinical study records. Studies on preclinical and clinical trials regarding oncolytic Herpes Simplex Virus (HSV), Adenovirus, Vacciniavirus and Reovirus were selected.

RESULTS

Enhanced infection and killing of tumor cells through capsid and genome modifications of OV were reported in recent preclinical studies. Most of the clinical studies were phase-I/II trials. In phase III studies, tumor regression and prolonged survival were observed after treatment with oncolytic HSV, Adenoviruses and Reoviruses. In most trials, OV were combined with chemoradiotherapy or immunotherapy.

CONCLUSION

In the published studies, OV treatment of HNC patients was safe, often well tolerated and showed promising results with regard to response and survival, especially in combination with chemoradiotherapy or checkpoint inhibitors.

Pathological Characteristics of Echovirus 30 Infection in a Mouse Model

Echovirus 30 (E30), a member of species B enterovirus, is associated with outbreaks of aseptic meningitis and has become a global health emergency. However, the pathogenesis of E30 remains poorly understood due to the lack of appropriate animal models. In this study, we established a mouse infection model to explore the pathogenicity of E30. The 2-day-old IFNAR^-/- mice infected with E30 strain WZ16 showed lethargy and paralysis, and some died. Obvious pathological changes were observed in the skeletal muscle, brain tissue, and other tissues, with the highest viral load in the skeletal muscles. Transcriptome analysis of brain and skeletal muscle tissues from infected mice showed that significant differentially expressed genes were enriched in complement response and neuropathy-related pathways. Using immunofluorescence assay, we found that the viral double-stranded RNA (dsRNA) was detected in the mouse brain region and could infect human glioma (U251) cells. These results indicated that E30 affects the nervous system, and they provide a theoretical basis for understanding its pathogenesis. IMPORTANCE Echovirus 30 (E30) infection causes a wide spectrum of diseases with mild symptoms, such as hand, foot, and mouth disease (HFMD), acute flaccid paralysis, and aseptic meningitis and other diseases, especially one of the most common pathogens causing aseptic meningitis outbreaks. We established a novel mouse model of E30 infection by inoculating neonatal mice with clinical isolates of E30 and observed the pathological changes induced by E30. Using the E30 infection model, we found complement responses and neuropathy-related genes in the mice tissues at the transcriptome level. Moreover, we found that the viral dsRNA localized in the mouse brain and could replicate in human glioma cell line U251 rather than in the neuroblastoma cell line, SK-N-SH.

NK Cell Effector Functions and Bystander Tumor Cell Killing in Immunovirotherapy

Oncolytic virotherapy is a compelling strategy to combine cancer gene therapy with immunotherapy. Lytic virus replication in malignant cells not only enables localized transgene expression based on engineered vectors but also triggers immunogenic tumor cell death and elicits inflammation in the tumor microenvironment. Modified oncolytic viruses encoding immunomodulators have been developed to enhance antitumor immune effects and therapeutic efficacy. As one example, bispecific molecules that engage immune cells to exert antitumor cytotoxicity can be encoded within the viral vector. This chapter describes an in vitro coculture experiment to study functionality and antitumor efficacy of engineered measles vaccine strain virus encoding natural killer cell engagers. In a flow cytometry-based analysis, target cell death of noninfected bystander cancer cells and effector functions of primary human natural killer cells are investigated. This methodology can facilitate assessment of advanced oncolytic viral vectors for cancer immunotherapy.

Is there impact of the SARS-CoV-2 pandemic on steroidogenesis and fertility?

In December of 2019, several cases of unknown atypical respiratory diseases emerged in Wuhan, Hubei Province in China. After preliminary research, it was stated that the disease is transmittable between humans and was named COVID-19. Over the course of next months, it spread all over the world by air and sea transport and caused a global pandemic which affects life of everyone now-a-days. A large number of countries, have since been forced to take precautions such as curfews, lockdowns, wearing facemasks etc. Even with vaccines being produced in mass numbers, lack of targeted therapy continues to be a major problem. According to studies so far it seems that elderly people are more vulnerable to severe symptoms while children tend to by asymptomatic or have milder form the disease. In our review, we focused on gathering data about the virus itself, its characteristics, paths of transmission, and its effect on hormone production and secretion. In such, there is insufficient information in the literature worldwide, especially the ones that focus on the effect of COVID-19 on individual organs systems within the human body. Hence, the present evidence-based study focused on the possible effects of COVID-19 on adrenal gland and gonads i.e. on the process of steroidogenesis and fertility.

Atypical presentation of COVID-19: Chronic bilateral testicular pain with lower extremity peripheral polyneuropathy, case report

In context of COVID-19 pandemic, there has been different presentations of the infection. The relationship of testicular pain with COVID-19 has not been extensively studied. We present a 31 years old male, with SARS-COV-2 infection, repeatedly consulting for intermittent bilateral testicular pain. Two months later he reported acute loss sensibility and pain in extremities, being diagnosed with axonal fine fiber polyneuropathy. Although the presence of SARS-COV-2 in testis remains controversial, there is a potential orchiepididymitis risk due to viral binding to ACE2 receptor in testicle, and also could induce systemic vasculitis as another possible cause of orchitis.

Cancer immunotherapy: Recent advances and challenges

Immunotherapy is a treatment that uses specific components of a person's immune system to fight diseases. This is usually done by stimulating or assisting one's immune system is attacking the offending agent - for instance, in the case of cancer - the target of immunotherapy will be cancer cells. Some types of immunotherapy are also called biologic therapy or biotherapy. One of the fundamental challenges that a living cell encounters are to accurately copy its genetic material to daughter cells during every single cell cycle. When this process goes haywire, genomic instability ensues, and genetic alterations ranging from nucleotide changes to chromosomal translocations and aneuploidy occur. Genomic instability arising out of DNA structural changes (indels, rearrangements, etc.,) can give rise to mutations predisposing to cancer. Cancer prevention refers to actions taken to mitigate the risk of getting cancer. The past decade has encountered an explosive rate of development of anticancer therapy ranging from standard chemotherapy to novel targeted small molecules that are nearly cancer specific, thereby reducing collateral damage. However, a new class of emerging therapy aims to train the body's defense system to fight against cancer. Termed as "cancer immunotherapy" is the new approach that has gained worldwide acceptance. It includes using antibodies that bind to and inhibit the function of proteins expressed by cancer cells or engineering and boosting the person's own T lymphocytes to target cancer. In this review, we summarized the recent advances and developments in cancer immunotherapy along with their shortcoming and challenges.

Cell surface heat shock protein-mediated entry of tumor cell-adapted rotavirus into U-937 cells

Rotaviruses infect cells by binding to specific cell surface molecules including gangliosides, heat shock protein cognate protein 70 (Hsc70), and some integrins. The characterization of cell surface receptors defining viral tropism is crucial for inhibiting entry into the normal cells or the cancer cells. In the present work, several tumor cell-adapted rotavirus isolates were tested for their interaction with some heat shock proteins (HSPs) present in the U-937 cells, derived from a human pleural effusion (histiocytic lymphoma monocyte). This interaction was examined by virus overlay protein-binding (VOPB), immunochemistry, immuno-dot blot assays, and flow cytometry. The results indicated that the rotavirus isolates studied were able to infect U937 cells by interacting with Hsp90, Hsp70, Hsp60, Hsp40, Hsc70, protein disulfide isomerase (PDI), and integrin β3, which are implicated in cellular proliferation, differentiation, and cancer development. Interestingly, these cellular proteins were found to be associated in lipid microdomains (rafts), facilitating in this way eventual sequential interactions of the rotavirus particles with the cell surface receptors. The rotavirus tropism for U937 cells through the use of these cell surface proteins made this rotavirus isolates an attractive target for the development of oncolytic strategies in the context of alternative and complementary treatment of cancer.

Oncolytic Virotherapy and Microenvironment in Multiple Myeloma

Multiple myeloma (MM) is a hematologic malignancy characterized by the accumulation of bone marrow (BM) clonal plasma cells, which are strictly dependent on the microenvironment. Despite the improvement of MM survival with the use of new drugs, MM patients still relapse and become always refractory to the treatment. The development of new therapeutic strategies targeting both tumor and microenvironment cells are necessary. Oncolytic virotherapy represent a promising approach in cancer treatment due to tumor-specific oncolysis and activation of the immune system. Different types of human viruses were checked in preclinical MM models, and the use of several viruses are currently investigated in clinical trials in MM patients. More recently, the use of alternative non-human viruses has been also highlighted in preclinical studies. This strategy could avoid the antiviral immune response of the patients against human viruses due to vaccination or natural infections, which could invalid the efficiency of virotherapy approach. In this review, we explored the effects of the main oncolytic viruses, which act through both direct and indirect mechanisms targeting myeloma and microenvironment cells inducing an anti-MM response. The efficacy of the oncolytic virus-therapy in combination with other anti-MM drugs targeting the microenvironment has been also discussed.

ACE2 Expression in Kidney and Testis May Cause Kidney and Testis Infection in COVID-19 Patients

In December 2019, a new type of pneumonia caused by SARS-Cov-2 (COVID-19) occurred in Wuhan and has been discovered in many countries around the world. ACE2 (angiotensin-converting enzyme 2) has been shown to be one of the major receptors that mediate the entry of SARS-Cov-2 into human cells. Here in this study, we used the online datasets to analyze ACE2 expression in different human organs. The results indicated that ACE2 highly expresses in renal tubular cells, Sertoli cells, Leydig cells, and cells in seminiferous ducts in testis. Recombinant SARS-CoV-2 spike protein (RBD) domain and ACE2 of RPTEC/SerC cell-binding assays confirmed that SARS-Cov-2 can bind to ACE2 on the surface of these cells. Our results suggest that ACE2 expression could contribute to kidney and testis infection after COVID-19 infection. Renal function evaluation and special care should be performed during clinical work. Clinicians should also pay attention to the risk of testicular lesions in patients during hospitalization and later clinical follow-up, especially the assessment and appropriate intervention in young patients' fertility.

Testicular pain as an unusual presentation of COVID-19: a brief review of SARS-CoV-2 and the testis

RESEARCH QUESTION

Can the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus induce testis damage and dysfunction?

DESIGN

This is the description of the case of a young man presenting with heavy testicular pain as the first symptom of COVID-19 infection. A review of the literature is also presented.

RESULTS

SARS-CoV-2 may enter into the host cell by binding to angiotensin-converting enzyme 2. This receptor seems to be widely expressed in different testicular cell types, making possible the occurrence of orchitis in male patients with COVID-19 infection. From a review of the literature, it seems that there is currently no evidence of sexual transmission of SARS-CoV-2; however, the possibility of virus-induced testis damage and dysfunction cannot be excluded.

CONCLUSIONS

Further studies are necessary on the pathological effect of SARS-CoV-2 in the male reproductive system and to ensure a proper andrological follow-up for male patients.

ACE2: Its potential role and regulation in severe acute respiratory syndrome and COVID-19

COVID-19, a new disease caused by the 2019-novel coronavirus (SARS-CoV-2), has swept the world and challenged its culture, economy, and health infrastructure. Forced emergence to find an effective vaccine to immunize people has led scientists to design and examine vaccine candidates all over the world. Until a vaccine is developed, however, effective treatment is needed to combat this virus, which is resistant to all conventional antiviral drugs. Accordingly, more about the structure, entry mechanism, and pathogenesis of COVID-19 is required. Angiotensin-converting enzyme 2 (ACE2) is the gateway to SARS-CoV and SARS-CoV-2, so our knowledge of SARS-CoV-2 can help us to complete its mechanism of interaction with ACE2 and virus endocytosis, which can be interrupted by neutralizing small molecules or proteins. ACE2 also plays a crucial role in lung injury.

Structures of Echovirus 30 in complex with its receptors inform a rational prediction for enterovirus receptor usage

Receptor usage that determines cell tropism and drives viral classification closely correlates with the virus structure. Enterovirus B (EV-B) consists of several subgroups according to receptor usage, among which echovirus 30 (E30), a leading causative agent for human aseptic meningitis, utilizes FcRn as an uncoating receptor. However, receptors for many EVs remain unknown. Here we analyzed the atomic structures of E30 mature virion, empty- and A-particles, which reveals serotype-specific epitopes and striking conformational differences between the subgroups within EV-Bs. Of these, the VP1 BC loop markedly distinguishes E30 from other EV-Bs, indicative of a role as a structural marker for EV-B. By obtaining cryo-electron microscopy structures of E30 in complex with its receptor FcRn and CD55 and comparing its homologs, we deciphered the underlying molecular basis for receptor recognition. Together with experimentally derived viral receptor identifications, we developed a structure-based in silico algorithm to inform a rational prediction for EV receptor usage.

Echovirus 30 (E30) belongs to the Enterovirus-B group and causes aseptic meningitis in humans. Here, the authors present the cryo-EM structures of the E30 E-particle, A-particle and the mature virion, as well as structures of E30 in complex with its receptor FcRn and CD55, and furthermore they describe a structure-based algorithm that allows the prediction of EV receptor usage.

Serotype specific epitopes identified by neutralizing antibodies underpin immunogenic differences in Enterovirus B

Echovirus 30 (E30), a serotype of Enterovirus B (EV-B), recently emerged as a major causative agent of aseptic meningitis worldwide. E30 is particularly devastating in the neonatal population and currently no vaccine or antiviral therapy is available. Here we characterize two highly potent E30-specific monoclonal antibodies, 6C5 and 4B10, which efficiently block binding of the virus to its attachment receptor CD55 and uncoating receptor FcRn. Combinations of 6C5 and 4B10 augment the sum of their individual anti-viral activities. High-resolution structures of E30-6C5-Fab and E30-4B10-Fab define the location and nature of epitopes targeted by the antibodies. 6C5 and 4B10 engage the capsid loci at the north rim of the canyon and in-canyon, respectively. Notably, these regions exhibit antigenic variability across EV-Bs, highlighting challenges in development of broad-spectrum antibodies. Our structures of these neutralizing antibodies of E30 are instructive for development of vaccines and therapeutics against EV-B infections.

So far no vaccine or antiviral therapy is available for Echovirus 30 (E30) that causes aseptic meningitis. Here, the authors generate and characterise two E30-specific monoclonal antibodies that block binding of the virus to its attachment receptor CD55 and uncoating receptor FcRn, and determine the cryo-EM structures of E30 with the bound neutralizing antibodies.

The limiting factors of oncolytic virus immunotherapy and the approaches to overcome them

Oncolytic virus (OV) immunotherapy is characterized by viruses which specifically target cancer cells and cause their cytolysis. They provide a unique and promising new tool for the eradication of cancer as they interact with and affect the tumor microenvironment (TME), vasculature, and immune system. Advancements of genetic engineering have allowed for these viruses to be armed in such a way to have enhanced targeting, strong immunomodulation properties, and an ability to modify the TME. However, there are still major limitations in their use, mostly due to difficulties in delivering the viral particles to the tumors and in ensuring that the immunomodulatory properties are able to stimulate the host immune response to mount a complete response. Using novel delivery systems and using OVs as a complementary therapy in a combinatorial treatment have shown some significant successes. In this review, we discuss the major issues and difficulties in using OVs as anti-tumor agents and some of the strategies put in place so far to overcome these limitations. KEY POINTS: • Oncolytic viruses (OVs) infect cancer cells and cause their cytolysis. • The major limitations in using OVs as anti-tumor therapy were discussed. • The potential strategies to overcome these limitations were summarized.

Induction of Cell Death in the Human Acute Lymphoblastic Leukemia Cell Line Reh by Infection with Rotavirus Isolate Wt1-5

Cancer is a major health problem that poses a great challenge to health care systems worldwide. Tools for cancer treatment have rapidly advanced in recent years, resulting in therapeutic strategies which are alternative and complementary to conventional treatment. To identify the cell surface receptors used by a tumor cell-adapted rotavirus and the cell death markers induced by its infection, we use Wt1-5, a rotavirus isolate recently adapted to tumor cells, to infect the human acute lymphoblastic leukemia cell line, Reh. The expression of cell surface receptors used by Wt1-5 was determined using flow cytometry and an antibody blocking assay to test for their implication in virus infection. Viral antigens and cell death markers induced by rotavirus infection were followed by flow cytometric analysis. The present study showed that rotavirus Wt1-5 was able to use cell surface proteins such as heat shock proteins (HSPs) 90, 70, 60 and 40, Hsc70, PDI and integrin β3. Rotavirus Wt1-5 induced cytotoxic effects including changes in cell membrane permeability, alteration of mitochondrial membrane potential, DNA fragmentation and activation of cell death signaling. Wt1-5 deserves to be further studied as a candidate oncolytic agent due to its ability to induce apoptosis in lymphoblastic leukemia-derived cells.

PATHOLOGICAL ANATOMY OF INFECTION CAUSED BY SARS-COV-2

Autopsy data from 80 patients who died of the COVID-19 infection were analysed. Using macro- and microscopic studies, specific features of pathological processes in various organs were identified. The obtained experimental data, along with information from literature sources, allowed conclusions to be drawn about the mechanisms of damaging internal organs and body systems, as well as assumptions to be made about individual links in the pathogenesis of COVID-19. The thanatogenesis of the disease and the main causes of death are discussed, including acute cardiopulmonary failure, acute renal failure, pulmonary thromboembolism, shock involving multiple organ failure and sepsis. The critical importance of autopsy is emphasized, which provides valuable information on the morphological substrate for this infection closely associated with possible clinical manifestations.

Mechanisms involved in the development of thrombocytopenia in patients with COVID-19

Corona Virus Disease 2019 (COVID-19) is caused by the novel coronavirus SARS-CoV-2. Emerging genetic and clinical evidence suggests similarities between COVID-19 patients and those with severe acute respiratory syndrome and Middle East respiratory syndrome. Hematological changes such as lymphopenia and thrombocytopenia are not rare in COVID-19 patients, and a smaller population of these patients had leukopenia. Thrombocytopenia was detected in 5–41.7% of the patients with COVID-19. Analyzing the dynamic decrease in platelet counts may be useful in the prognosis of patients with COVID-19. However, the mechanisms underlying the development of thrombocytopenia remain to be elucidated. This review summarizes the hematological changes in patients infected with SARS-CoV-2 and possible underlying mechanisms of thrombocytopenia development.

•

Early diagnosis and treatment of COVID-19 patients can reduce mortality.

•

There is no laboratory test index to predict disease progression and prognosis.

•

Progressive decline in platelets may be a prognostic factor for COVID-19 patients.

•

Monitoring platelet count may be an effective index for COVID-19 progression.

ACE2 Expression in Kidney and Testis May Cause Kidney and Testis Infection in COVID-19 Patients

In December 2019, a new type of pneumonia caused by SARS-Cov-2 (COVID-19) occurred in Wuhan and has been discovered in many countries around the world. ACE2 (angiotensin-converting enzyme 2) has been shown to be one of the major receptors that mediate the entry of SARS-Cov-2 into human cells. Here in this study, we used the online datasets to analyze ACE2 expression in different human organs. The results indicated that ACE2 highly expresses in renal tubular cells, Sertoli cells, Leydig cells, and cells in seminiferous ducts in testis. Recombinant SARS-CoV-2 spike protein (RBD) domain and ACE2 of RPTEC/SerC cell-binding assays confirmed that SARS-Cov-2 can bind to ACE2 on the surface of these cells. Our results suggest that ACE2 expression could contribute to kidney and testis infection after COVID-19 infection. Renal function evaluation and special care should be performed during clinical work. Clinicians should also pay attention to the risk of testicular lesions in patients during hospitalization and later clinical follow-up, especially the assessment and appropriate intervention in young patients' fertility.