Identification and validation of an anoikis-associated gene signature to predict clinical character, stemness, IDH mutation, and immune filtration in glioblastoma.

Background: Glioblastoma (GBM) is the most prominent and aggressive primary brain tumor in adults. Anoikis is a specific form of programmed cell death that plays a key role in tumor invasion and metastasis. The presence of anti-anoikis factors is associated with tumor aggressiveness and drug resistance. Methods: The non-negative matrix factorization algorithm was used for effective dimension reduction for integrated datasets. Differences in the tumor microenvironment (TME), stemness indices, and clinical characteristics between the two clusters were analyzed. Difference analysis, weighted gene coexpression network analysis (WGCNA), univariate Cox regression, and least absolute shrinkage and selection operator regression were leveraged to screen prognosis-related genes and construct a risk score model. Immunohistochemistry was performed to evaluate the expression of representative genes in clinical specimens. The relationship between the risk score and the TME, stemness, clinical traits, and immunotherapy response was assessed in GBM and pancancer. Results: Two definite clusters were identified on the basis of anoikis-related gene expression. Patients with GBM assigned to C1 were characterized by shortened overall survival, higher suppressive immune infiltration levels, and lower stemness indices. We further constructed a risk scoring model to quantify the regulatory patterns of anoikis-related genes. The higher risk score group was characterized by a poor prognosis, the infiltration of suppressive immune cells and a differentiated phenotype, whereas the lower risk score group exhibited the opposite effects. In addition, patients in the lower risk score group exhibited a higher frequency of isocitrate dehydrogenase (IDH) mutations and a more sensitive response to immunotherapy. Drug sensitivity analysis was performed, revealing that the higher risk group may benefit more from drugs targeting the PI3K/mTOR signaling pathway. Conclusion: We revealed potential relationships between anoikis-related genes and clinical features, TME, stemness, IDH mutation, and immunotherapy and elucidated their therapeutic value.

IL-22-induced cell extrusion and IL-18-induced cell death prevent and cure rotavirus infection.

Bacterial flagellin can elicit production of TLR5-mediated IL-22 and NLRC4-mediated IL-18 cytokines that act in concert to cure and prevent rotavirus (RV) infection. This study investigated the mechanism by which these cytokines act to impede RV. Although IL-18 and IL-22 induce each other's expression, we found that IL-18 and IL-22 both impeded RV independently of one another and did so by distinct mechanisms that involved activation of their cognate receptors in intestinal epithelial cells (IEC). IL-22 drove IEC proliferation and migration toward villus tips, which resulted in increased extrusion of highly differentiated IEC that serve as the site of RV replication. In contrast, IL-18 induced cell death of RV-infected IEC thus directly interrupting the RV replication cycle, resulting in spewing of incompetent virus into the intestinal lumen and causing a rapid drop in the number of RV-infected IEC. Together, these actions resulted in rapid and complete expulsion of RV, even in hosts with severely compromised immune systems. These results suggest that a cocktail of IL-18 and IL-22 might be a means of treating viral infections that preferentially target short-lived epithelial cells.

Intrahepatic metastases may be specific to hepatocellular carcinoma due to the coagulation and fibrinolytic systems (Review).

Hepatocellular carcinoma (HCC) is different from other solid tumors because it is commonly associated with the occurrence of intrahepatic metastasis. Additionally, the liver, unlike other organs, is the main site of coagulation and fibrinolytic factor production. Therefore, it was speculated that coagulation and fibrinolytic factors could be associated with intrahepatic metastasis of HCC. Do the coagulation and fibrinolytic systems protect HCC cells against anoikis during infiltration and metastasis? Conversely, do the coagulation and fibrinolytic systems lead to immune escape of HCC cells by affecting the immune microenvironment of patients? The current review aimed to present a number of novel hypotheses for the treatment of HCC by exploring the mechanisms of coagulation and fibrinolytic factors in the regulation of cancer growth.

Beyond glycoproteins as galectin counterreceptors: tumor-effector T cell growth control via ganglioside GM1 [corrected].

Glycoprotein glycan chains, by virtue of structure, topology of presentation and connection to signal-inducing units, are functional galectin counterreceptors. As example, cross-linking of the α(5)ß(1) integrin by galectin-1 on carcinoma cells leads to G(1) arrest or anoikis. Contact-dependent switching from proliferation to differentiation in cultured neuroblastoma cells (SK-N-MC) also utilizes galectin-1. Activity enhancement of a cell surface sialidase underlies the shift in glycan display to ganglioside GM1. Its pentasaccharide within microdomains becomes the target. Similarly, this recognition pair is upregulated upon T cell activation. Cross-linking of GM1 along with associated α(4)/α(5)ß(1) integrins elicits Ca(2+)-influx via TRPC5 channels as the relevant response for T effector cell (T(eff)) suppression. Unlike T(eff) cells from wild-type mice, those from genetically altered mice lacking GM1 are not suppressed by galectin-1 or regulatory T cells. Similarly, in the context of GM1 deficiency in NOD mice, T(eff) cells are associated with resistance to regulatory T cell suppression, which is reversed by applied GM1. The broad array of glycosphingolipid structures suggests the possible existence of several novel counterreceptors targeted to endogenous lectins, with sulfatide-galectin-4 interplay within apical delivery serving as recent example.

Salivary epithelial cells from Sjogren's syndrome patients are highly sensitive to anoikis induced by TLR-3 ligation.

In certain types of cells, Toll-like receptor-3 (TLR-3) ligation by viral dsRNA induces apoptotic death, likely engaged into the elimination of virus-infected cells. We have previously shown that TLR-3 ligation on cultured non-neoplastic salivary gland epithelial cells (SGEC) with polyI:C (a synthetic analogue of viral dsRNA) results in the induction of surface immunoactive molecules, however, the pro-apoptotic effect of such signaling has not been addressed. In this study, polyI:C-treated SGEC were found to suffer severe detachment from substratum and subsequent apoptosis, a phenomenon suggestive of anoikis or anoikia (detachment-induced apoptosis). PolyI:C-induced anoikis in SGEC was associated with the upregulation of the pro-apoptotic Bmf, BimEL and Bax and the down-regulation of the pro-survival Bcl-2 (real-time PCR analyses). Finally, the comparative analysis of SGEC lines derived from primary Sjogren's syndrome (SS) patients (SS-SGEC) and non-SS controls had revealed that SS-SGEC are particularly susceptible to TLR-3-induced anoikis, as it was triggered by suboptimally low concentrations of polyI:C. This finding correlated with significantly higher constitutive surface TLR-3 expression by SS-SGEC, a feature indicative of their intrinsic activation status. In conclusion, TLR-3 signaling pathway in the salivary epithelium appears to extend beyond the induction of innate immune responses and to involve the activation of programmed-cell death via anoikis. In the same context, the increased vulnerability of SS-SGEC to the injurious effect of TLR-3 ligation is likely associated with the intrinsic activation processes that apparently operate in the epithelia of SS patients, and a feature of key pathogenetic importance for the disorder.

Fibulin-6 expression and anoikis in human salivary gland epithelial cells: implications in Sjogren's syndrome.

Important changes in acinar and ductal morphology and function, together with pronounced extracellular matrix (ECM) remodelling, are detectable in the labial salivary glands of Sjögren's syndrome (SS) patients. The objective of this work was to determine the effect of treatment with the anti-Ro/SSA auto-antibodies, characterizing SS, on the expression of fibulin-6, a member of the fibulins family of the ECM, in primary human salivary gland epithelial cell (SGEC) cultures established from biopsies of labial minor salivary glands obtained from healthy donors. The induction of cell detachment and anoikis in SGECs treated with anti-Ro/SSA auto-antibodies were also investigated. Changes in fibulin-6 mRNA expression were measured by semi-quantitative reverse transcriptase-PCR and real-time PCR. Fibulin-6 expression in cells treated with anti-Ro/SSA auto-antibodies was evaluated by flow cytometric analysis and confocal laser scanning microscopy. SGECs undergoing death by anoikis were identified and quantified using Calcein blue/YOPRO-1 dyes. Herein, we present the first evidence of fibulin-6 expression in SGEC that results distributed in the cytoplasm surrounding the inner side of the plasma membrane. Fibulin-6 was down-regulated in SGECs treated with anti-Ro/SSA auto-antibodies in which a marked cell detachment and a reduction of cell viability were observed. Notably, a reduction of fibulin-6 expression in SGECs treated with anti-Ro/SSA auto-antibodies corresponds to an increase of anoikis cell death. Our observations demonstrate a dysregulation of fibulin-6 in the pathological processes observed in SS and provide new evidence that disorganization of the ECM environment could damage the architecture and function of the salivary glands.

Anti-Ro/SSA autoantibody-mediated regulation of extracellular matrix fibulins in human epithelial cells of the salivary gland.

OBJECTIVES: The fibulins are a family of extracellular matrix (ECM) molecules that regulate the organ shape along with other growth factors and stromal cells and have recently been shown to be involved in a variety of cellular functions including proliferation, migration, differentiation, and survival. Important changes in acinar and ductal morphology and function, together with pronounced ECM remodelling, are detectable in the labial salivary glands (LSGs) of patients with Sjögren's syndrome (SS). Here we report the in vitro expression of the recently identified ECM proteins fibulin-6 and fibulin-7 by human salivary gland epithelial cells (SGECs). The ability of anti-Ro/SSA autoantibodies (Abs) to modulate fibulin-6 and fibulin-7 expression was investigated. METHODS: Semiquantitative reverse transcription polymerase chain reaction (RT-PCR) and real-time PCR were used to analyse fibulin-6 and fibulin-7 mRNA expression. Confocal microscopy and fluorescence-activated cell sorting (FACS) were used to study expression of the proteins in primary human SGEC cultures, established from biopsies of minor LSGs, in both untreated control cells and anti-Ro/SSA Abs-treated cells. RESULTS: The methods used show the expression of fibulin-6 and fibulin-7 in SGECs. Treatment of cells with anti-Ro/SSA Abs results in a down-regulation of fibulin-6 mRNA expression whereas no significant differences were observed in fibulin-7 expression between untreated and treated cells. CONCLUSION: Dysregulation of fibulin expression in SGECs by anti-Ro/SSA Abs may contribute to disorganization of the ECM environment and thus cause injury to the salivary gland architecture and functionality observed in SS.

Survivin identifies keratinocyte stem cells and is downregulated by anti-beta1 integrin during anoikis.

Survivin belongs to the family of inhibitor of apoptosis proteins and is involved in regulation of cell death as well as cell division. Here, we show that wild-type (WT) survivin is expressed in a subpopulation of basal keratinocytes in normal human skin at the cytoplasmic level. WT survivin is highly expressed in keratinocyte stem cells (KSCs), whereas its mRNA level decreases in transit amplifying (TA) cells and disappears in postmitotic (PM) cells. Likewise, WT survivin protein is expressed in KSCs, almost undetectable in TA cells, and absent in PM cells. Real time polymerase chain reaction demonstrates that the putative antiapoptotic isoforms survivin-2B and survivin-DeltaEx3 are expressed at the highest levels in KSCs, whereas they tend to decrease in TA cells and disappear in PM cells. On the contrary, the putative proapoptotic variants of survivin, survivin-3B, and survivin-2alpha tend to be high in PM and TA cells and are almost absent in KSCs. By confocal microscopy, survivin is predominantly expressed at the nuclear level in KSCs, which proliferate significantly better than TA cells, which, in turn, express mostly cytosolic WT survivin. Blocking beta1 integrin signal downregulates WT survivin mRNA and protein expression and induces apoptosis (anoikis) in KSCs. On the other hand, inhibition of beta1 integrin upregulates mRNA expression of survivin-2alpha. Taken together, these results indicate that survivin identifies human KSCs. Expression of nuclear survivin could reflect the different behavior between KSCs in vitro and in vivo, in terms of proliferation. Finally, survivin could be part of the "niche" protection by preventing anoikis in KSCs.

Lactoferrin-enhanced anoikis: a defense against neonatal necrotizing enterocolitis.

Enteral nutrition with human milk lowers the incidence of necrotizing enterocolitis in preterm human infants. Lactoferrin, the major whey protein in human milk, has many functions related to host defense against bacterial infection. Here, we hypothesize that lactoferrin also helps terminate bacterial invasion of enterocytes via a detachment-induced apoptosis called anoikis. Death of infected epithelia by anoikis prevents local spread of bacterial pathogens because the bacteria are trapped within the cell. Such infected, apoptotic and sloughed epithelia also cannot infect the lower gastrointestinal tract, and the epithelia exit the body in the stool. Currently, anoikis is a phenomenon related to the renewal of enterocytes, and it is not recognized as an anti-bacterial host defense. We suggest that anoikis of infected enterocytes is a process in which lactoferrin plays an important role. In a pilot study in which neonatal rats were pre-treated with intra-gastric recombinant human lactoferrin, we found evidence of epithelia with anoikis in ileal fluid after enteric infection. This finding was rarely seen in infected neonatal rats without pre-treatment with lactoferrin. Quantitative analysis of intestinal lavage specimens and quantitative stereology of apoptotic epithelia in this model will be required to verify the theory. We propose that oral use of recombinant human lactoferrin might have these hypothesized and other anti-bacterial effects in preterm infants, and hence, this protein might prevent necrotizing enterocolitis in preterm infants who cannot take human milk.