Evaluation of ST6Gal1 expression and clinicopathological significance in human glioma.

Glioma is the most common brain tumor, accounting for a large majority of cancer-related deaths. ß-galactoside α2, 6 sialyltranferase 1 (ST6Gal1), the primary enzyme responsible for the conjugation of α2, 6 sialic acids to protein and lipid targets, is strongly associated with the occurrence and development of several brain tumor types. Still, the expression, targets, and functions of ST6Gal1 in glioma patients remain undetermined. As sialylation of the Ig-like cell adhesion family molecules have prominent roles in the latter's regulation in other biological contexts, we screened for members that have potential to be regulated by ST6Gal1 in silico and examined co-expressed protein modules using data derived from the Cancer Genome Atlas (TCGA) database, and we identified neural cell adhesion molecule (NCAM1) as a major ST6Gal1-interacting target. Bioinformatic binding analysis confirmed the interaction of ST6Gal1 and NCAM1. Immunohistochemistry was then used to evaluate post-operative samples from 156 patients with gliomas. ST6Gal1 and NCAM1 were co-expressed in gliomas, and their expression correlated significantly (p = 0.002) by univariate analysis. Our study also found that the expression levels of both ST6Gal1 and NCAM1 corresponded negatively with glioma grade, isocitrate dehydrogenase (IDH) mutation, and proliferation index (Ki67). Consistently, Kaplan-Meier survival curves showed that lower ST6Gal1 and NCAM1 protein levels are linked to unfavorable outcomes in glioma patients (p = 0.018 and p < 0.001, respectively). Our data indicate that ST6Gal1 may participate in the inhibition of oncogenesis and malignant progression via interacting with and targeting NCAM1 in glioma, thus presenting a novel strategy for intervention.

The FOXO3-FOXM1 axis: A key cancer drug target and a modulator of cancer drug resistance.

The FOXO3 and FOXM1 forkhead box transcription factors, functioning downstream of the essential PI3K-Akt, Ras-ERK and JNK/p38MAPK signalling cascades, are crucial for cell proliferation, differentiation, cell survival, senescence, DNA damage repair and cell cycle control. The development of resistance to both conventional and newly emerged molecularly targeted therapies is a major challenge confronting current cancer treatment in the clinic. Intriguingly, the mechanisms of resistance to 'classical' cytotoxic chemotherapeutics and to molecularly targeted therapies are invariably linked to deregulated signalling through the FOXO3 and FOXM1 transcription factors. This is owing to the involvement of FOXO3 and FOXM1 in the regulation of genes linked to crucial drug action-related cellular processes, including stem cell renewal, DNA repair, cell survival, drug efflux, and deregulated mitosis. A better understanding of the mechanisms regulating the FOXO3-FOXM1 axis, as well as their downstream transcriptional targets and functions, may render these proteins reliable and early diagnostic/prognostic factors as well as crucial therapeutic targets for cancer treatment and importantly, for overcoming chemotherapeutic drug resistance.

Cancer cell immune mimicry delineates onco-immunologic modulation.

Immune transcripts are essential for depicting onco-immunologic interactions. However, whether cancer cells mimic immune transcripts to reprogram onco-immunologic interaction remains unclear. Here, single-cell transcriptomic analyses of 7,737 normal and 37,476 cancer cells reveal increased immune transcripts in cancer cells. Cells gradually acquire immune transcripts in malignant transformation. Notably, cancer cell-derived immune transcripts contribute to distinct prognoses of immune gene signatures. Optimized immune response signature (oIRS), obtained by excluding cancer-related immune genes from immune gene signatures, and offers a more reliable prognostic value. oIRS reveals that antigen presentation, NK cell killing and T cell signaling are associated with favorable prognosis. Patients with higher oIRS expression are associated with favorable responses to immunotherapy. Indeed, CD83+ cell infiltration, which indicates antigen presentation activity, predicts favorable prognosis in breast cancer. These findings unveil that immune mimicry is a distinct cancer hallmark, providing an example of cancer cell plasticity and a refined view of tumor microenvironment.

FOXK2 Transcription Factor and Its Emerging Roles in Cancer.

Forkhead box (FOX) transcription factors compose a large family of regulators of key biological processes within a cell. FOXK2 is a member of FOX family, whose biological functions remain relatively unexplored, despite its description in the early nineties. More recently, growing evidence has been pointing towards a role of FOXK2 in cancer, which is likely to be context-dependent and tumour-specific. Here, we provide an overview of important aspects concerning the mechanisms of regulation of FOXK2 expression and function, as well as its complex interactions at the chromatin level, which orchestrate how it differentially regulates the expression of gene targets in pathophysiology. Particularly, we explore the emerging functions of FOXK2 as a regulator of a broad range of cancer features, such as cell proliferation and survival, DNA damage, metabolism, migration, invasion and metastasis. Finally, we discuss the prognostic value of assessing FOXK2 expression in cancer patients and how it can be potentially targeted for future anticancer interventions.

ER stress and cancer: The FOXO forkhead transcription factor link.

The endoplasmic reticulum (ER) is a cellular organelle with central roles in maintaining proteostasis due to its involvement in protein synthesis, folding, quality control, distribution and degradation. The accumulation of misfolded proteins in the ER lumen causes 'ER stress' and threatens overall cellular proteostasis. To restore ER homeostasis, cells evoke an evolutionarily conserved adaptive signalling and gene expression network collectively called the 'unfolded protein response (UPR)', a complex biological process which aims to restore proteostasis. When ER stress is overwhelming and beyond rectification, the normally pro-survival UPR can shift to induce cell termination. Emerging evidence from mammalian, fly and nematode worm systems reveals that the FOXO Forkhead proteins integrate upstream ER stress and UPR signals with the transcriptional machinery to decrease translation, promote cell survival/termination and increase the levels of ER-resident chaperones and of ER-associated degradation (ERAD) components to restore ER homeostasis. The high rates of protein synthesis/translation associated with cancer cell proliferation and metabolism, as well as mutations resulting in aberrant proteins, also induce ER stress and the UPR. While the pro-survival side of the UPR underlies its ability to sustain and promote cancers, its apoptotic functions can be exploited for cancer therapies by offering the chance to 'flick the proteostatic switch'. To this end, further studies are required to fully reevaluate the roles and regulation of these UPR signalling molecules, including FOXO proteins and their targets, in cancer initiation and progression as well as the effects on inhibiting their functions in cancer cells. This information will help to establish these UPR signalling molecules as possible therapeutic targets and putative biomarkers in cancers.

Dataset of the human homologues and orthologues of lipid-metabolic genes identified as DAF-16 targets their roles in lipid and energy metabolism.

The data presented in this article are related to the review article entitled 'Unravelling the role of fatty acid metabolism in cancer through the FOXO3-FOXM1 axis' (Saavedra-Garcia et al., 2017) [24]. Here, we have matched the DAF-16/FOXO3 downstream genes with their respective human orthologues and reviewed the roles of these targeted genes in FA metabolism. The list of genes listed in this article are precisely selected from literature reviews based on their functions in mammalian FA metabolism. The nematode Caenorhabditis elegans gene orthologues of the genes are obtained from WormBase, the online biological database of C. elegans. This dataset has not been uploaded to a public repository yet.

The pterocarpanquinone LQB-118 induces apoptosis in acute myeloid leukemia cells of distinct molecular subtypes and targets FoxO3a and FoxM1 transcription factors.

Acute myeloid leukemia (AML) patients' outcome is usually poor, mainly because of drug resistance phenotype. The identification of new drugs able to overcome mechanisms of chemoresistance is essential. The pterocarpanquinone LQB-118 compound has been shown to have a potent cytotoxic activity in myeloid leukemia cell lines and patient cells. Our aim was to investigate if LQB-118 is able to target FoxO3a and FoxM1 signaling pathways while sensitizing AML cell lines. LQB-118 induced apoptosis in both AML cell lines HL60 (M3 FAB subtype) and U937 (M4/M5 FAB subtype). Cell death occurred independently of alterations in cell cycle distribution. In vivo administration revealed that LQB-118 was not cytotoxic to normal bone marrow-derived cells isolated from mice. LQB-118 induced FoxO3a nuclear translocation and upregulation of its direct transcriptional target Bim, in HL60 cells. However, LQB-118 induced FoxO3a nuclear exclusion, followed by Bim downregulation, in U937 cells. Concomitantly, LQB-118 exposure reduced FoxM1 and Survivin expression in U937 cells, but this effect was more subtle in HL60 cells. Taken together, our data suggest that LQB-118 has a selective and potent antitumor activity against AML cells with distinct molecular subtypes, and it involves differential modulation of the signaling pathways associated with FoxO3a and FoxM1 transcription factors.