Relapsing COVID-19 in a Patient With Non-Hodgkin Lymphoma on Chemotherapy

Hematologic malignancies and chemotherapy are risk factors for COVID-19 progression and mortality. Immunocompromised hosts, particularly those with severe B-cell depletion, can shed viable viruses for extended periods, which can lead to persistent infection. We present the case of a 73-year-old male with diffuse large B-cell lymphoma (stage IV-B) under curative immunochemotherapy with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). After the first episode of mild COVID-19, he developed two severe relapses following the third and fourth cycles of R-CHOP. Lung CT scans performed in both episodes showed new-onset ground-glass infiltrates and fibrosis of previously affected pulmonary segments. In light of similar semiquantitative SARS-CoV-2 viral loads between episodes, without further risk exposure or microbiological findings, persistent COVID-19 with severe clinical relapses was assumed and successfully treated with polyclonal immunoglobulin and remdesivir. Whole-genome sequencing was performed in all samples, confirming the same specimen, which belonged to the B.1.177 lineage. This case stands out for the unusually long viral persistence and the various relapses of severe COVID-19 related to the worsening immune status with each immunochemotherapy cycle.info:eu-repo/semantics/publishedVersio

RNA interference-mediated knockdown of p21WAF1 enhances anti-tumor cell activity of oncolytic adenoviruses

The ability of oncolytic adenoviruses to replicate in and lyse cancer cells offers a potential therapeutic approach. However, selectivity and efficacy of adenovirus replication need to be improved. In this study, we present that loss of p21WAF1 promotes adenovirus replication and more effective cell killing. To test our hypothesis, we took HCT116 colon cancer cell lines carrying deletions of either p21WAF1 or p53, and infected these cell lines with wild-type adenovirus (WtD) or the oncolytic adenoviruses, ONYX-015 and Delta-24. We found that WtD, ONYX-015 and Delta-24 induced stronger cytopathic effects in HCT116 p21−/− cells compared with HCT116-WT cells. This was accompanied by increased virus production. siRNA-mediated knockdown of p21WAF1, and similarly of p27KIP1, in HCT116-WT cells also enhanced replication of and cell killing by these viruses. Furthermore, we found that TE7, an esophageal carcinoma cell line, also showed a strong cell-killing effect and virus production when p21WAF1 expression was suppressed by RNA interference before adenoviruses infection. Also, H1299 and DU-145 cells transfected with p21WAF1 siRNA showed higher virus production after ONYX-015 and Delta-24 infections. These observations suggest that p21WAF1 plays a role in mediating replication of oncolytic viruses with potential implications for adenoviral therapy of cancer

Molecular association of glucose-6- phosphate isomerase and pyruvate kinase M2 with glyceraldehyde-3-phosphate dehydrogenase in cancer cells

Background: For a long time cancer cells are known for increased uptake of glucose and its metabolization through glycolysis. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key regulatory enzyme of this pathway and can produce ATP through oxidative level of phosphorylation. Previously, we reported that GAPDH purified from a variety of malignant tissues, but not from normal tissues, was strongly inactivated by a normal metabolite, methylglyoxal (MG).Molecular mechanism behind MG mediated GAPDH inhibition in cancer cells is not well understood. Methods: GAPDH was purified from Ehrlich ascites carcinoma (EAC) cells based on its enzymatic activity. GAPDH associated proteins in EAC cells and 3-methylcholanthrene (3MC) induced mouse tumor tissue were detected by mass spectrometry analysis and immunoprecipitation (IP) experiment, respectively. Interacting domains of GAPDH and its associated proteins were assessed by in silico molecular docking analysis. Mechanism of MG mediated GAPDH inactivation in cancer cells was evaluated by measuring enzyme activity, Circular dichroism (CD) spectroscopy, IP and mass spectrometry analyses. Result: Here, we report that GAPDH is associated with glucose-6-phosphate isomerase (GPI) and pyruvate kinase M2 (PKM2) in Ehrlich ascites carcinoma (EAC) cells and also in 3-methylcholanthrene (3MC) induced mouse tumor tissue. Molecular docking analyses suggest C-terminal domain preference for the interaction between GAPDH and GPI. However, both C and N termini of PKM2 might be interacting with the C terminal domain of GAPDH. Expression of both PKM2 and GPI is increased in 3MC induced tumor compared with the normal tissue. In presence of 1 mM MG,association of GAPDH with PKM2 or GPI is not perturbed, but the enzymatic activity of GAPDH is reduced to 26.8 ± 5 % in 3MC induced tumor and 57.8 ± 2.3 % in EAC cells. Treatment of MG to purified GAPDH complex leads to glycation at R399 residue of PKM2 only, and changes the secondary structure of the protein complex. Conclusion: PKM2 may regulate the enzymatic activity of GAPDH. Increased enzymatic activity of GAPDH in tumor cells may be attributed to its association with PKM2 and GPI. Association of GAPDH with PKM2 and GPI could be a signature for cancer cells. Glycation at R399 of PKM2 and changes in the secondary structure of GAPDH complex could be one of the mechanisms by which GAPDH activity is inhibited in tumor cells by MG

Novel roles for GAPDH in cell death and carcinogenesis

Publicado en línea el 25 de septiembre de 2009Growing evidence points to the fact that glucose metabolism has a central role in carcinogenesis. Among the enzymes controlling this energy production pathway, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is of particular interest. Initially identified as a glycolytic enzyme and considered as a housekeeping gene, this enzyme is actually tightly regulated and is involved in numerous cellular functions. Particularly intriguing are recent reports describing GAPDH as a regulator of cell death. However, its role in cell death is unclear; whereas some studies point toward a proapoptotic function, others describe a protective role and suggest its participation in tumor progression. In this study, we highlight recent findings and discuss potential mechanisms through which cells regulate GAPDH to fulfill its diverse functions to influence cell fate.This work was supported in part by l’Association pour la Recherche sur le Cancer, by l’Agence Nationnal de la Recherche, la Fondation de France, Plan Nacional I+D SAF2008-04974 and by grants from The U.S. National Institutes of Health. J-E.R. is a recipient of a contrat d’interface INSERM-CHU de Nice.Peer reviewe

CIB1 prevents nuclear GAPDH accumulation and non-apoptotic tumor cell death via AKT and ERK signaling

CIB1 is a 22-kDa regulatory protein previously implicated in cell survival and proliferation. However, the mechanism by which CIB1 regulates these processes is poorly defined. Here we report that CIB1 depletion in SK-N-SH neuroblastoma and MDA-MB-468 breast cancer cells promotes non-apoptotic, caspase-independent cell death that is not initiated by increased outer mitochondrial membrane permeability or translocation of apoptosis-inducing factor to the nucleus. Instead, cell death requires nuclear GAPDH accumulation. Furthermore, CIB1 depletion disrupts two commonly dysregulated, oncogenic pathways– PI3K/AKT and Ras/MEK/ERK, resulting in a synergistic mechanism of cell death, which was mimicked by simultaneous pharmacological inhibition of both pathways, but not either pathway alone. In defining each pathway’s contributions, we found that AKT inhibition alone maximally induced GAPDH nuclear accumulation, whereas MEK/ERK inhibition alone had no effect on GAPDH localization. Concurrent GAPDH nuclear accumulation and ERK inhibition were required however, to induce a significant DNA damage response, which was critical to subsequent cell death. Collectively, our results indicate that CIB1 is uniquely positioned to regulate PI3K/AKT and MEK/ERK signaling and that simultaneous disruption of these pathways synergistically induces a nuclear GAPDH-dependent cell death. The mechanistic insights into cell death induced by CIB1 interference suggest novel molecular targets for cancer therapy