Aneuploidy and oncoviruses

Role of the VEGF in virus-associated cancers

The role of numerous risk factors, including consumption of alcohol, smoking, having diet high in fat and sugar and many other items, on caner progression cannot be denied. Viral diseases are one these factors, and they can initiate some signalling pathways causing cancer. For example, they can be effective on providing oxygen and nutrients by inducing VEGF expression. In this review article, we summarised the mechanisms of angiogenesis and VEGF expression in cancerous tissues which are infected with oncoviruses (Epstein-Barr virus, Human papillomavirus infection, Human T-lymphotropic virus, Kaposi's sarcoma-associated herpesvirus, Hepatitis B and hepatitis C virus).

Single-cell multi-omics sequencing reveals chromosome copy number inconsistency between trophectoderm and inner cell mass in human reconstituted embryos after spindle transfer

STUDY QUESTION

Is the chromosome copy number of the trophectoderm (TE) of a human reconstituted embryos after spindle transfer (ST) representative of the inner cell mass (ICM)?

SUMMARY ANSWER

Single-cell multi-omics sequencing revealed that ST blastocysts have a higher proportion of cell lineages exhibiting intermediate mosaicism than conventional ICSI blastocysts, and that the TE of ST blastocysts does not represent the chromosome copy number of ICM.

WHAT IS KNOWN ALREADY

Preimplantation genetic testing for aneuploidy (PGT-A) assumes that TE biopsies are representative of the ICM, but the TE and ICM originate from different cell lineages, and concordance between TE and ICM is not well-studied, especially in ST embryos.

STUDY DESIGN, SIZE, DURATION

We recruited 30 infertile women who received treatment at our clinic and obtained 45 usable blastocysts (22 from conventional ICSI and 23 reconstituted embryos after ST). We performed single-cell multi-omics sequencing on all blastocysts to predict and verify copy number variations (CNVs) in each cell. We determined the chromosome copy number of each embryo by analysing the proportion of abnormal cells in each blastocyst. We used the Bland-Altman concordance and the Kappa test to evaluate the concordance between TE and ICM in the both groups.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study was conducted at a public tertiary hospital in China, where all the embryo operations, including oocytes retrieval, ST, and ICSI, were performed in the embryo laboratory. We utilized single-cell multi-omics sequencing technology at the Biomedical Pioneering Innovation Center, School of Life Sciences, Peking University, to analyse the blastocysts. Transcriptome sequencing was used to predict the CNV of each cell through bioinformatics analysis, and the results were validated using the DNA methylation library of each cell to confirm chromosomal normalcy. We conducted statistical analysis and graphical plotting using R 4.2.1, SPSS 27, and GraphPad Prism 9.3.

MAIN RESULTS AND THE ROLE OF CHANCE

Mean age of the volunteers, the blastocyst morphology, and the developmental ratewere similar in ST and ICSI groups. The blastocysts in the ST group had some additional chromosomal types that were prone to variations beyond those enriched in the blastocysts of the ICSI group. Finally, both Bland-Altman concordance test and kappa concordancetest showed good chromosomal concordance between TE and ICM in the ICSI blastocysts (kappa = 0.659, P < 0.05), but not in ST blastocysts (P = 1.000), suggesting that the TE in reconstituted embryos is not representative of ICM. Gene functional annotation (GO and KEGG analyses) suggests that there may be new or additional pathways for CNV generation in ST embryos compared to ICSI embryos.

LIMITATIONS, REASONS FOR CAUTION

This study was mainly limited by the small sample size and the limitations of single-cell multi-omics sequencing technology. To select eligible single cells, some cells of the embryos were eliminated or not labelled, resulting in a loss of information about them. The findings of this study are innovative and exploratory. A larger sample size of human embryos (especially ST embryos) and more accurate molecular genetics techniques for detecting CNV in single cells are needed to validate our results.

WIDER IMPLICATIONS OF THE FINDINGS

Our study justifies the routine clinical use of PGT-A in ICSI blastocysts, as we found that the TE is a good substitute for ICM in predicting chromosomal abnormalities. While PGT-A is not entirely accurate, our data demonstrate good clinical feasibility. This trial was able to provide correct genetic counselling to patients regarding the reliability of PGT-A. Regarding ST blastocysts, the increased mosaicism rate and the inability of the TE to represent the chromosomal copy number of the ICM are both biological characteristics that differentiate them from ICSI blastocysts. Currently, ST is not used clinically on a large scale to produce blastocysts. However, if ST becomes more widely used in the future, our study will be the first to demonstrate that the use of PGT-A in ST blastocysts may not be as accurate as PGT-A for ICSI blastocysts.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the National Key R&D Program of China (2018YFA0107601) and the National Key R&D Program of China (2018YFC1003003). The authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

An Update on the Metabolic Landscape of Oncogenic Viruses

Viruses play an important role in cancer development as about 12% of cancer types are linked to viral infections. Viruses that induce cellular transformation are known as oncoviruses. Although the mechanisms of viral oncogenesis differ between viruses, all oncogenic viruses share the ability to establish persistent chronic infections with no obvious symptoms for years. During these prolonged infections, oncogenic viruses manipulate cell signaling pathways that control cell cycle progression, apoptosis, inflammation, and metabolism. Importantly, it seems that most oncoviruses depend on these changes for their persistence and amplification. Metabolic changes induced by oncoviruses share many common features with cancer metabolism. Indeed, viruses, like proliferating cancer cells, require increased biosynthetic precursors for virion production, need to balance cellular redox homeostasis, and need to ensure host cell survival in a given tissue microenvironment. Thus, like for cancer cells, viral replication and persistence of infected cells frequently depend on metabolic changes. Here, we draw parallels between metabolic changes observed in cancers or induced by oncoviruses, with a focus on pathways involved in the regulation of glucose, lipid, and amino acids. We describe whether and how oncoviruses depend on metabolic changes, with the perspective of targeting them for antiviral and onco-therapeutic approaches in the context of viral infections.

Prevalence of HSV, Varicella-Zoster, CMV, EBV and HPV in the oral cavity and the larynx carcinoma in Iran

Introduction: Viral diseases can have roles in oral cavity and larynx carcinoma. However, the relationship between HPV, herpetic infection and these cancers is not clear. Materials & methods: DNA of tissues from oral and larynx carcinoma was extracted and the presence of HPV, HSV-1, HSV-2, EBV, CMV and Varicella Zoster virus was detected. Results: We detected five HSV-1 in oral cavity cancer and two HSV-1 in larynx carcinoma. Also, four and two HPV-positive in oral cavity and larynx carcinoma were found, respectively. There were five HPV type 18 and one HPV type 31. None of our samples were infected with EBV, CMV, HSV-2 and Varicella Zoster virus. Conclusion: A higher prevalence of HPV and HSV-1 in cancerous tissues in comparison with normal ones was detected.

Cyclin-dependent kinases and CDK inhibitors in virus-associated cancers

The role of several risk factors, such as pollution, consumption of alcohol, age, sex and obesity in cancer progression is undeniable. Human malignancies are mainly characterized by deregulation of cyclin-dependent kinases (CDK) and cyclin inhibitor kinases (CIK) activities. Viruses express some onco-proteins which could interfere with CDK and CIKs function, and induce some signals to replicate their genome into host's cells. By reviewing some studies about the function of CDK and CIKs in cells infected with oncoviruses, such as HPV, HTLV, HERV, EBV, KSHV, HBV and HCV, we reviewed the mechanisms of different onco-proteins which could deregulate the cell cycle proteins.