SARS-CoV-2, persistence & suppression of cell internal clearing-signals
results showed that SC2 infected cells had high expression of pre-apoptosis pathways, but low expression of final IFN-α. Consistent w/ SC2 subverting IFN signaling in infected cells journals.asm.org/doi/10.1128/mb…
SARS-CoV-2, IFN-α & cancer
IFN-α is a cytokine that mediates immune responses to infected cells & tumour cells
SC2 inhibits IFN-α expression. Thus SC2 infected cells evade needed cell-death & produce more virions. If some also become cancerous, they more likely multiply&persist
SARS-CoV-2 & accelerating breast cancer
in addition to high risk of SC2 infection, cancer patients likely have higher risk of accelerated cancer progression after infection …
"Recent studies suggest pathogenetic mechanisms common for both SARS-CoV-2 and oncogenesis. SARS-CoV-2 exploits host immunity stimulates signalling and oncogenic pathways and may establish an oncogenic microenvironment" frontiersin.org/articles/10.33…
There is growing evidence of SARS-CoV-2 modulating oncogenic pathways, promoting chronic low-grade inflammation & causing tissue damage. Main relationships between SC2 & cancer are summarized, showing proposed biochemical cellular transformation mechanisms ncbi.nlm.nih.gov/pmc/articles/P…
1/2 Study reports possible hijacking of EGFR & related downstream signaling pathways by SARS-CoV-2 Spike 1 protein & its RBD in lung cancer cells (A549).
Also: Spike 1 & RBD also elicited the activation of a key marker for the survival of cancer cells. mdpi.com/2076-393X/11/4…
2/2 epidermal growth factor receptor (EGFR) is a growth factor receptor that induces cell differentiation & proliferation upon activation. In pathological settings, EGFR (overexpression) is a sign of growth-signal independence & a driver of tumorigenesis.
1/2 authors add evidence showing more general connection of SARS-CoV-2 and cancer, in line with several other carcinogenic viral infections.
I.e. p53 expression is downregulated in COVID-19 patients & persists at least 24 weeks in long COVID-19 patients.
Evasion of anti-growth signaling is an important characteristic of cancer cells. To continue to proliferate, cancer cells uncouple themselves from signals for slowing down cell growth.
17 genes were upregulated by SARS-CoV-2 e.g.: CCNB2, ESPL1, TTK, CCNA2, CCNB1, CDC6, CDC20, CDK1, BUB1, CHEK1, BUB1B, CDC45, PLK1, CCNA1, ORC1 & E2F1. This is linked to cancers of the breast, digestive tract, bone, endometrial, skin, brain, lung cancer ... researchsquare.com/article/rs-189…
Paper gives an overview of strategies SARS-CoV-2 uses to potentially cause cancer stem cell to develop in different organs w/ focus on lung cancer, colorectal cancer, pancreatic adenocarcinoma, breast cancer, oral cancer
On a molecular level, COVID-19 hearts displayed a distinct expression gene pattern primarily coding for factors involved in angiogenesis & epithelial-mesenchymal transition (EMT), changes not seen in any other patient groups. ncbi.nlm.nih.gov/pmc/articles/P…
2/4 SARS-CoV-2 & angiogenesis
Results show COVID-19 was associated w/ increased immunoexpression of biomarkers involved in endothelial dysfunction, microthrombosis, & angiogenesis compared to the H1N1 and CONTROL groups. ncbi.nlm.nih.gov/pmc/articles/P…
3/4 SARS-CoV-2 & angiogenesis
vascular injuries accompanied by thrombosis, vasoconstriction & distinct intussusceptive angiogenesis, a rapid process of blood vessel neoformation by splitting a vessel by an incorporation of circulating angiogenic cells erj.ersjournals.com/content/56/5/2…
4/4 angiogenesis & cancer
Angiogenesis is the growth of blood vessels from existing vasculature. It plays a critical role in cancer growth b/c solid tumors need a blood supply. Tumors can cause such blood supplies to form by giving off signals that stimulate angiogenesis.
this thread 👆 is part of a more general thread 👇 that goes through all of the "Hallmarks of Cancer" and if SARS-CoV-2 infected cells fulfill all of the hallmarks
there are many dozens of papers & case studies concerning SC2 as potentially cancer causing, but SC2 has not yet been officially classified as carcinogenic
There are at least seven reported strategies, which are utilized by SARS-CoV-2 for immune evasion. ncbi.nlm.nih.gov/pmc/articles/P…
2/12 SARS-CoV-2 & avoiding immune destruction
In addition to immune evasion, SC2 infected cells can avoid distruction by preventing proper function of immune system (IS) cells &/or infecting IS cells. Cells such as: CD4 & CD8 T cells, neurophils, monocytes, macrophages, NK cells
* telomere shortening & the age acceleration effect
* infection of cells w/ upregulated telomerase
* downregulation of TRF2, leading to excessive loss of telomeric DNA
* ultimately: cancer
2/35 Telomeres (1)
A brief intro. T protect chromosomal DNA terminal regions from progressive degradation & ensure linear chromosome integrity by preventing DNA repair systems from mistaking the very ends of DNA strands for a double-strand breaks. en.m.wikipedia.org/wiki/Telomere
3/35 Telomeres (2)
T "cap" end-sequences & are progressively degraded in the DNA replication process. Thus w/ each cell split T length (TL) shortens.
For most human cells there is an inverse correlation between TL & biological age. See also: Hayflick limit en.m.wikipedia.org/wiki/Hayflick_…
A collection of papers concerning GI tract persistence.
In many case nasal & throat swabs will be negative
& GI samples or anal/stool swabs are positive weeks to months after infection
It is misleading to only rely on nasal & throat swabs
2/14 SARS-CoV-2 & GI tract persistence
+70% of +ve retest patients had viral RNA in their anal swabs at 2nd admission. SC2 RNA was 2x more often detected in anal swabs than in throat. Results show SC2 was mainly detected in GI tract in +ve retest patients nature.com/articles/s4142…
3/14 SARS-CoV-2 & GI tract persistence
data suggest the possibility of extended duration of viral shedding in faeces, for nearly 5 weeks after the patients' respiratory samples tested negative for SARS-CoV-2 RNA. sciencedirect.com/science/articl…
1/11 SARS-CoV-2 & rapid loss of acquired immunity:
a 🧵 collecting various papers & results leading up to an idea:
rapid waning is
* actually chronic antigen exposure of a persistent SARS-CoV-2 infection
* leading to depletion/exhaustion of
* SC2 acquired immune memory
2/11 HIV, CD4+ depletion & SARS-CoV-2:
Math. model shows if "runaway" hypothesis in HIV were correct, CD4+ cells would fall to low levels w/in a few months, not years.
SARS-CoV-2: when infecting lymphocytes, it mainly infected CD4+ cells & triggered pronounced T-cell death. Infected lymphocytes likely carry virus to all parts of the body via blood circulation. nature.com/articles/s4139…