Kaiso differentially regulates components of the Notch signaling pathway in intestinal cells

Dissecting the Kaiso binding profile in clear renal cancer cells

BACKGROUND

There has been a notable increase in interest in the transcriptional regulator Kaiso, which has been linked to the regulation of clonal hematopoiesis, myelodysplastic syndrome, and tumorigenesis. Nevertheless, there are no consistent data on the binding sites of Kaiso in vivo in the genome. Previous ChIP-seq analyses for Kaiso contradicted the accumulated data of Kaiso binding sites obtained in vitro. Here, we studied this discrepancy by characterizing the distribution profile of Kaiso binding sites in Caki-1 cells using Kaiso-deficient cells as a negative control, and compared its pattern on chromatin with that in lymphoblastoid cell lines.

RESULTS

We employed Caki-1 kidney carcinoma cells and their derivative, which lacks the Kaiso gene, as a model system to identify the genomic targets of Kaiso. The principal binding motifs for Kaiso are CGCG and CTGCNAT, with 60% of all binding sites containing both sequences. The significance of methyl-DNA binding activity was confirmed through examination of the genomic distribution of the E535A mutant variant of Kaiso, which cannot bind methylated DNA in vitro but is able to interact with CTGCNA sequences. Our findings indicate that Kaiso is present at CpG islands with a preference for methylated ones. We identified Kaiso target genes whose methylation and transcription are dependent on its expression. Furthermore, Kaiso binding sites are enriched at CpG islands, with partial methylation at the 5' and/or 3' boundaries. We discovered CpG islands exhibiting wave-like methylation patterns, with Kaiso detected in the majority of these areas. Similar data were obtained in other cell lines.

CONCLUSION

The present study delineates the genomic distribution of Kaiso in cancer cells, confirming its role as a factor with a complex mode of DNA binding and a strong association with CpG islands, particularly with methylated and eroded CpG islands, revealing a new potential Kaiso target gene-SQSTM1, involved in differentiation of acute myeloid leukemia cells. Furthermore, we discovered the existence of a new class of CpG islands characterized by wave-like DNA methylation.

Hepatic Amyloid Beta-42-Metabolizing Proteins in Liver Steatosis and Metabolic Dysfunction-Associated Steatohepatitis

Amyloid beta (Aβ) plays a major role in the pathogenesis of Alzheimer's disease and, more recently, has been shown to protect against liver fibrosis. Therefore, we studied Aβ-42 levels and the expression of genes involved in the generation, degradation, and transport of Aβ proteins in liver samples from patients at different stages of metabolic dysfunction-associated liver disease (MASLD) and under steatotic conditions in vitro/in vivo. Amyloid precursor protein (APP), key Aβ-metabolizing proteins, and Aβ-42 were analyzed using RT-PCR, Western blotting, Luminex analysis in steatotic in vitro and fatty liver mouse models, and TaqMan qRT-PCR analysis in hepatic samples from patients with MASLD. Hepatocytes loaded with palmitic acid induced APP, presenilin, and neprilysin (NEP) expression, which was reversed by oleic acid. Increased APP and NEP, decreased BACE1, and unchanged Aβ-42 protein levels were found in the steatotic mouse liver compared to the normal liver. Aβ-42 concentrations were low in MASLD samples of patients with moderate to severe fibrosis compared to the livers of patients with mild or no MASLD. Consistent with the reduced Aβ-42 levels, the mRNA expression of proteins involved in APP degradation (ADAM9/10/17, BACE2) and Aβ-42 cleavage (MMP2/7/9, ACE) was increased. In the steatotic liver, the expression of APP- and Aβ-metabolizing proteins is increased, most likely related to oxidative stress, but does not affect hepatic Aβ-42 levels. Consistent with our previous findings, low Aβ-42 levels in patients with liver fibrosis appear to be caused by the reduced production and enhanced non-amyloidogenic processing of APP.

Kaiso Expression in Triple Negative Breast Cancer in a Tertiary Hospital in Ghana

Background

Breast cancer has produced more lost disability-adjusted life years (DALYs) than any other type of cancer. The prevalence of the disease, especially triple negative breast cancer (TNBC) in Africa is on the rise, with poor survival rates. With the great advancements in treatments of breast cancers, that of TNBC is still a challenge due to its narrowed treatment options and poor disease prognosis. This research seeks to explore the expression of kaiso in Ghanaian breast cancer and how they may modulate clinicopathological features, and disease prognosis.

Methodology

A cross-sectional retrospective study was conducted on formalin-fixed paraffin-embedded (FFPE) breast cancer tissues retrieved from the archives of the pathology unit of Komfo Anokye Teaching Hospital (KATH). Immunohistochemistry assessment was performed on haematoxylin and eosin-stained slides selected for tissue microarray construction. Data were analysed using SPSS version 28 and Microsoft excel 2013.

Results

55.3% of the cases tested negative to progesterone receptor (PR), oestrogen receptor (ER), and human epidermal growth receptor 2 (HER2). There were significant associations between menopausal status and molecular subtype (p=0.010), Kaiso expression and histological diagnoses (<0.001) and Kaiso against lymphovascular invasion (0.050). However, there were no significant associations between Kaiso localization and the clinicopathological features although 63.9% of the expression was seen in the nucleus.

Conclusion

The study indicates that Kaiso is highly expressed in Ghanaian TNBC and likely associated with worse outcomes in aggressive tumour types.

Relationship between High Expression of Kaiso Protein and Poor Prognosis of Lung Cancer and the Regulation Mechanism of Malignant Phenotype of Lung Cancer Cells

In this study, Kaiso was discovered to be a unique member of the POZ-zinc fingers family of transcription factors, which has been implicated in the genesis and progression of cancer. Although there is still some debate, Kaiso is believed to be implicated in the development of human cancer. It should be noted that there is minimal evidence available on the therapeutic relevance of nuclear Kaiso in lung cancer in humans. Histone or DNA modifications that control gene activity outside of the underlying sequence are examples of epigenetic alternations. Epigenetic alterations are heritable but reversible. Human illness, such as lung cancer, is often related to epigenetic dysregulation. In preclinical and clinical studies, epigenetic-targeted therapy has shown significant therapeutic promise for solid tumours and has been used in the treatment of haematological malignancies using different medicines targeting epigenetic regulators. It is important to note that the abnormal activities of Kaiso enzymes in tumour growth are summarised below and the development of inhibitors or medicines targeting epigenetic enzyme regulation is highlighted.

Cytochrome P450 26A1 Modulates the Polarization of Uterine Macrophages During the Peri-Implantation Period

Uterine M1/M2 macrophages activation states undergo dynamic changes throughout pregnancy, and inappropriate macrophages polarization can cause adverse pregnancy outcomes, especially during the peri-implantation period. Our previous studies have confirmed that Cytochrome P450 26A1 (CYP26A1) can affect embryo implantation by regulating uterine NK cells and DCs. The aim of this study was to investigate whether CYP26A1 regulates the polarization of uterine macrophages in early pregnancy. Here, we observed that Cyp26a1 was significantly upregulated in M1 as compared with M2 of uterine macrophages, Raw264.7 and iBMDM. Knockdown of CYP26A1 in mice uterine significantly decreased the number of embryo implantation sites and the proportion of CD45⁺F4/80⁺CD206⁻ M1-like uterine macrophages. Primary uterine macrophages treated with anti-CYP26A1 antibody expressed significantly lower levels of M1 markers Nos2, Il1b, Il6 and Tnf-a. In CYP26A1 knockout Raw264.7 cells, the protein levels of M1 markers TNF-α, IL-6 and CD86 were significantly decreased as compared with the wild type cells. Moreover, CYP26A1 deficiency decreased the ability to produce nitric oxide and increased the phagocytosis capacity of Raw264.7 cells under M1 stimulation state. The re-introduction of CYP26A1 partially reversed the polarization levels of M1 in CYP26A1 knockout Raw264.7 cells. CYP26A1 may regulate the polarization of uterine macrophages to M1 through Stap1 and Slc7a2. In summary, these results indicate that CYP26A1 plays a significant role in macrophage polarization, and knockdown of CYP26A1 can cause insufficient M1 polarization during the peri-implantation period, which has adverse effects on blastocyst implantation.

Transcription Factors: The Fulcrum Between Cell Development and Carcinogenesis

Higher eukaryotic development is a complex and tightly regulated process, whereby transcription factors (TFs) play a key role in controlling the gene regulatory networks. Dysregulation of these regulatory networks has also been associated with carcinogenesis. Transcription factors are key enablers of cancer stemness, which support the maintenance and function of cancer stem cells that are believed to act as seeds for cancer initiation, progression and metastasis, and treatment resistance. One key area of research is to understand how these factors interact and collaborate to define cellular fate during embryogenesis as well as during tumor development. This review focuses on understanding the role of TFs in cell development and cancer. The molecular mechanisms of cell fate decision are of key importance in efforts towards developing better protocols for directed differentiation of cells in research and medicine. We also discuss the dysregulation of TFs and their role in cancer progression and metastasis, exploring TF networks as direct or indirect targets for therapeutic intervention, as well as specific TFs' potential as biomarkers for predicting and monitoring treatment responses.

Kaiso regulates osteoblast differentiation and mineralization via the Itga10/PI3K/AKT signaling pathway

Bone homeostasis is maintained by a dynamic balance between bone formation and bone resorption. The cellular activities of osteoblasts and osteoclasts are the primary factors that maintain this dynamic balance. The transcription factor Kaiso has been identified as a regulator of cell proliferation and differentiation in various cells. However, research into its role in bone homeostasis is currently lacking. In the present study, cell and animal experiments were conducted to investigate the role of Kaiso in bone homeostasis. The present study identified that Kaiso was downregulated during osteoblast differentiation in MC3T3-E1 cells. Gain- and loss-of-function studies in MC3T3-E1 cells demonstrated that Kaiso served a critical role in osteoblast differentiation in vitro. The findings were further confirmed in vivo. The results of the sequence analysis indicated that Kaiso influenced osteoblast differentiation and mineralization by regulating the PI3K/AKT signaling pathway. Moreover, integrin subunit α10 (Itga10) was identified as a direct target of Kaiso via chromatin immunoprecipitation and luciferase reporter assays. Collectively, these findings suggested that Kaiso regulated the differentiation of osteoblasts via the Itga10/PI3K/AKT pathway, which represents a therapeutic target for bone formation or bone resorption-related diseases.

Stem Cell Signaling Pathways in the Small Intestine

The ability of stem cells to divide and differentiate is necessary for tissue repair and homeostasis. Appropriate spatial and temporal mechanisms are needed. Local intercellular signaling increases expression of specific genes that mediate and maintain differentiation. Diffusible signaling molecules provide concentration-dependent induction of specific patterns of cell types or regions. Differentiation of adjacent cells, on the other hand, requires cell–cell contact and subsequent signaling. These two types of signals work together to allow stem cells to provide what organisms require. The ability to grow organoids has increased our understanding of the cellular and molecular features of small “niches” that modulate stem cell function in various organs, including the small intestine.

Kaiso-induced intestinal inflammation is preceded by diminished E-cadherin expression and intestinal integrity

Chronic intestinal inflammation contributes to pathologies such as inflammatory bowel disease (IBD) and colon cancer. While the precise etiology remains controversial, IBD is believed to manifest as a result of various factors. We previously reported that intestinal-specific overexpression of the transcription factor Kaiso results in an intestinal inflammatory response; however, the cause of this inflammation is unknown. To elucidate the underlying mechanism(s) of the Kaiso-mediated intestinal inflammatory phenotype, we evaluated two independent transgenic mouse lines that express varying levels of Kaiso (Kaiso^Tg). Histological analyses of Kaiso^Tg mice revealed intestinal damage including thickening of the mucosa, intestinal “lesions” and crypt abscesses, which are reminiscent of IBD pathology. Additionally, higher Kaiso levels induced intestinal neutrophilia as early as 12 weeks, which worsened as the mice aged. Notably, the Kaiso-induced intestinal inflammation correlated with a leaky intestinal barrier and mis-regulation of E-cadherin expression and localization. Interestingly, Kaiso overexpression resulted in reduced proliferation but enhanced migration of intestinal epithelial cells prior to the onset of inflammation. Collectively, these data suggest that Kaiso plays a role in regulating intestinal epithelial cell integrity and function, dysregulation of which contributes to a chronic inflammatory phenotype as mice age.

Dancing from bottoms up - Roles of the POZ-ZF transcription factor Kaiso in Cancer

The POZ-ZF transcription factor Kaiso was discovered two decades ago as a binding partner for p120^ctn. Since its discovery, roles for Kaiso in diverse biological processes (epithelial-to-mesenchymal transition, apoptosis, inflammation) and several signalling pathways (Wnt/β-catenin, TGFβ, EGFR, Notch) have emerged. While Kaiso's biological role in normal tissues has yet to be fully elucidated, Kaiso has been increasingly implicated in multiple human cancers including colon, prostate, ovarian, lung, breast and chronic myeloid leukemia. In the majority of human cancers investigated to date, high Kaiso expression correlates with aggressive tumor characteristics including proliferation and metastasis, and/or poor prognosis. More recently, interest in Kaiso stems from its apparent correlation with racial disparities in breast and prostate cancer incidence and survival outcomes in people of African Ancestry. This review discusses Kaiso's role in various cancers, and Kaiso's potential for driving racial disparities in incidence and/or outcomes in people of African ancestry.

Effect of Notch and PARP Pathways' Inhibition in Leukemic Cells

Differentiation of blood cells is one of the most complex processes in the body. It is regulated by the action of transcription factors in time and space which creates a specific signaling network. In the hematopoietic signaling system, Notch is one of the main regulators of lymphocyte development. The aim of this study was to get insight into the regulation of Notch signalization and the influence of poly(ADP-ribose)polymerase (PARP) activity on this process in three leukemia cell lines obtained from B and T cells. PARP1 is an enzyme involved in posttranslational protein modification and chromatin structure changes. B and T leukemia cells were treated with Notch and PARP inhibitors, alone or in combination, for a prolonged period. The cells did not show cell proliferation arrest or apoptosis. Analysis of gene and protein expression set involved in Notch and PARP pathways revealed increase in JAGGED1 expression after PARP1 inhibition in B cell lines and changes in Ikaros family members in both B and T cell lines after γ-secretase inhibition. These data indicate that Notch and PARP inhibition, although not inducing differentiation in leukemia cells, induce changes in signaling circuits and chromatin modelling factors.

The POZ-ZF transcription factor Znf131 is implicated as a regulator of Kaiso-mediated biological processes

Znf131 belongs to the family of POZ-ZF transcription factors, but, in contrast to most other characterized POZ-ZF proteins that function as transcriptional repressors, Znf131 acts as a transcriptional activator. Znf131 heterodimerizes with the POZ-ZF protein Kaiso, which itself represses a subset of canonical Wnt target genes, including the cell cycle regulator Cyclin D1. Herein, we report a possible role for Znf131 in Kaiso-mediated processes. Notably, we found that Znf131 associates with several Kaiso target gene promoters, including that of CCND1. ChIP analysis revealed that Znf131 indirectly associates with the CCND1 promoter in HCT116 and MCF7 cells via a region that encompasses the previously characterized +69 Kaiso Binding Site, hinting that the Znf131/Kaiso heterodimer may co-regulate Cyclin D1 expression. We also demonstrate that Kaiso inhibits Znf131 expression, raising the possibility that Kaiso and Znf131 act to fine-tune target gene expression. Together, our findings implicate Znf131 as a co-regulator of Kaiso-mediated biological processes.