Notch signalling pathway in development of cholangiocarcinoma

Analysing potent biomarkers along phytochemicals for breast cancer therapy: an in silico approach

PURPOSE

This research focused on the identification of herbal compounds as potential anti-cancer drugs, especially for breast cancer, that involved the recognition of Notch downstream targets NOTCH proteins (1-4) specifically expressed in breast tumours as biomarkers for prognosis, along with P53 tumour antigens, that were used as comparisons to check the sensitivity of the herbal bio-compounds.

METHODS

After investigating phytochemical candidates, we employed an approach for computer-aided drug design and analysis to find strong breast cancer inhibitors. The present study utilized in silico analyses and protein docking techniques to characterize and rank selected bio-compounds for their efficiency in oncogenic inhibition for use in precise carcinomic cell growth control.

RESULTS

Several of the identified phytocompounds found in herbs followed Lipinski's Rule of Five and could be further investigated as potential medicinal molecules. Based on the Vina score obtained after the docking process, the active compound Epigallocatechin gallate in green tea with NOTCH (1-4) and P53 proteins showed promising results for future drug repurposing. The stiffness and binding stability of green tea pharmacological complexes were further elucidated by the molecular dynamic simulations carried out for the highest scoring phytochemical ligand complex.

CONCLUSION

The target-ligand complex of green tea active compound Epigallocatechin gallate with NOTCH (1-4) had the potential to become potent anti-breast cancer therapeutic candidates following further research involving wet-lab experiments.

The interplay of signaling pathways with miRNAs in cholangiocarcinoma pathogenicity and targeted therapy

Cholangiocarcinoma (CCA), the second most frequent liver cancer after hepatocellular carcinoma, has been rising worldwide in recent epidemiological research. This neoplasia's pathogenesis is poorly understood. Yet, recent advances have illuminated the molecular processes of cholangiocyte malignancy and growth. Late diagnosis, ineffective therapy, and resistance to standard treatments contribute to this malignancy's poor prognosis. So, to develop efficient preventative and therapy methods, the molecular pathways that cause this cancer must be better understood. MicroRNAs (miRNAs) are non-coding ribonucleic acids (ncRNAs) that influence gene expression. Biliary carcinogenesis involves abnormally expressed miRNAs that act as oncogenes or tumor suppressors (TSs). The miRNAs regulate multiple gene networks and are involved in cancer hallmarks like reprogramming of cellular metabolism, sustained proliferative signaling, evasion of growth suppressors, replicative immortality, induction/access to the vasculature, activation of invasion and metastasis, and avoidance of immune destruction. In addition, numerous ongoing clinical trials are demonstrating the efficacy of therapeutic strategies based on miRNAs as powerful anticancer agents. Here, we will update the research on CCA-related miRNAs and explain their regulation involved in the molecular pathophysiology of this malignancy. Eventually, we will disclose their potential as clinical biomarkers and therapeutic tools in CCA.

Regulatory RNAs, microRNA, long-non coding RNA and circular RNA roles in colorectal cancer stem cells

The properties of cancer stem cells (CSCs), such as self-renewal, drug resistance, and metastasis, have been indicated to be responsible for the poor prognosis of patients with colon cancers. The epigenetic regulatory network plays a crucial role in CSC properties. Regulatory non-coding RNA (ncRNA), including microRNAs, long noncoding RNAs, and circular RNAs, have an important influence on cell physiopathology. They modulate cells by regulating gene expression in different ways. This review discusses the basic characteristics and the physiological functions of colorectal cancer (CRC) stem cells. Elucidation of these ncRNAs will help us understand the pathological mechanism of CRC progression, and they could become a new target for cancer treatment.

Cholecystectomy reduces the risk of cholangiocarcinoma in patients with complicated gallstones, but has negligible effect on hepatocellular carcinoma

BACKGROUND AND AIM

Gallstones have been reported to be positively associated with hepatobiliary cancers. However, risks of these cancers by cholecystectomy or in patients with complicated gallstones are controversial. We studied the effect of cholecystectomy on the risk of cholangiocarcinoma (CCA) or hepatocellular carcinoma (HCC) in patients with gallstones and subgroup of complicated gallstones.

METHODS

Patients with gallstone disease (n = 958 677) and age-matched and sex-matched controls (n = 9 586 770) were identified using the Korean National Health Insurance database. Complicated gallstones were defined as gallstones associated with acute cholecystitis or acute cholangitis. Adjusted hazard ratios (adjusted hazard ratios, 95% confidence interval) of CCA and HCC incidences were evaluated in patients with gallstones who received cholecystectomy compared to the controls. We also analyzed these effects in patients with complicated gallstones.

RESULTS

Patients with gallstones showed increased risks of CCA (1.80, 1.67-1.93) and HCC (1.03, 1.00-1.07) compared with controls. Cholecystectomy had minimal effects on the risks of CCA (1.94, 1.76-2.14) and HCC (0.93, 0.87-0.99) compared with those without cholecystectomy. However, patients with complicated gallstones showed highly increased CCA risk (5.62, 4.89-6.46) and a 30% risk reduction after cholecystectomy (3.91, 3.43-4.46). Risk reduction by cholecystectomy was greater for extrahepatic CCA than for intrahepatic CCA or ampulla of Vater cancer. However, the risk of HCC was not different in patients with complicated gallstones and those who underwent cholecystectomy compared to controls.

CONCLUSION

The risk of CCA was markedly increased in patients with complicated gallstones and was partially reduced by cholecystectomy. The risk change of HCC was minimal with gallstones or cholecystectomy.

CD90 is regulated by notch1 and hallmarks a more aggressive intrahepatic cholangiocarcinoma phenotype

BACKGROUND

Intrahepatic Cholangiocarcinoma (iCCA) is characterized by a strong stromal reaction playing a role in tumor progression. Thymus cell antigen 1 (THY1), also called Cluster of Differentiation 90 (CD90), is a key regulator of cell-cell and cell-matrix interaction. In iCCA, CD90 has been reported to be associated with a poor prognosis. In an iCCA PDX model, we recently found that CD90 was downregulated in mice treated with the Notch γ-secretase inhibitor Crenigacestat. The study aims to investigate the role of CD90 in relation to the NOTCH pathway.

METHODS

THY1/CD90 gene and protein expression was evaluated in human iCCA tissues and xenograft models by qRT-PCR, immunohistochemistry, and immunofluorescence. Notch1 inhibition was achieved by siRNA. THY1/CD90 functions were investigated in xenograft models built with HuCCT1 and KKU-M213 cell lines, engineered to overexpress or knockdown THY1, respectively.

RESULTS

CD90 co-localized with EPCAM, showing its epithelial origin. In vitro, NOTCH1 silencing triggered HES1 and THY1 down-regulation. RBPJ, a critical transcriptional regulator of NOTCH signaling, exhibited putative binding sites on the THY1 promoter and bound to the latter, implying CD90 as a downstream NOTCH pathway effector. In vivo, Crenigacestat suppressed iCCA growth and reduced CD90 expression in the PDX model. In the xenograft model, Crenigacestat inhibited tumor growth of HuCCT1 cells transfected to overexpress CD90 and KKU-M213 cells constitutively expressing high levels of CD90, while not affecting the growth of HuCCT1 control cells and KKU-M213 depleted of CD90. In an iCCA cohort, patients with higher expression levels of NOTCH1/HES1/THY1 displayed a significantly shorter survival.

CONCLUSIONS

iCCA patients with higher NOTCH1/HES1/THY1 expression have the worst prognosis, but they are more likely to benefit from Notch signaling inhibition. These findings represent the scientific rationale for testing NOTCH1 inhibitors in clinical trials, taking the first step toward precision medicine for iCCA.

ZSWIM8 is a myogenic protein that partly prevents C2C12 differentiation

Cell adhesion molecule-related/downregulated by oncogenes (Cdon) is a cell-surface receptor that mediates cell–cell interactions and positively regulates myogenesis. The cytoplasmic region of Cdon interacts with other proteins to form a Cdon/JLP/Bnip-2/CDC42 complex that activates p38 mitogen-activated protein kinase (MAPK) and induces myogenesis. However, Cdon complex may include other proteins during myogenesis. In this study, we found that Cullin 2-interacting protein zinc finger SWIM type containing 8 (ZSWIM8) ubiquitin ligase is induced during C2C12 differentiation and is included in the Cdon complex. We knocked-down Zswim8 in C2C12 cells to determine the effect of ZSWIM8 on differentiation. However, we detected neither ZSWIM8-dependent ubiquitination nor the degradation of Bnip2, Cdon, or JLP. In contrast, ZSWIM8 knockdown accelerated C2C12 differentiation. These results suggest that ZSWIM8 is a Cdon complex-included myogenic protein that prevents C2C12 differentiation without affecting the stability of Bnip2, Cdon, and JLP.

Notch-Hes1 signaling activation in Caroli disease and polycystic liver disease

The Notch signaling pathway plays a key role in the morphogenesis of the biliary tree, but its involvement in cystic biliary diseases, such as Caroli disease (CD) and polycystic liver disease (PLD), has yet to be determined. Immunostaining was performed using liver sections of CD and PLD, and the results were compared with those of congenital hepatic fibrosis (CHF) and von Meyenburg complex (VMC). The expression of Notch receptor 1 (Notch1) was increased in the nuclei of biliary epithelial cells in all cases of CD and PLD, whereas it remained at a low level in CHF and VMC. In addition, Notch2 and Notch3 were preferably expressed in the nuclei of biliary epithelial cells of PLD. Accordingly, the Notch effector Hes1 was highly expressed in biliary epithelial cells of CD and PLD, and the cell proliferative activity was significantly higher in CD and PLD. The expression of the Notch ligand Delta-like 1 was significantly increased in biliary epithelial cells of CD and PLD, which may be causally associated with the nuclear overexpression of Notch1 and Hes1. These results indicate that aberrant activation of the Notch-Hes1 signaling pathway may be responsible for the progression of biliary cystogenesis in CD and PLD.

YAP Accelerates Notch-Driven Cholangiocarcinogenesis via mTORC1 in Mice

Intrahepatic cholangiocarcinoma (iCCA) is a lethal malignant neoplasm with limited therapeutic options. Previous studies have found that Notch1 overexpression alone suffices to induce iCCA in the mouse, albeit after long latency. The current study found that activation of the Yes-associated protein (Yap) proto-oncogene occurs during Notch1-driven iCCA progression. After co-expressing activated Notch1 intracellular domain (Nicd) and Yap (YapS127A) in the mouse liver, rapid iCCA formation and progression occurred in Nicd/Yap mice. Mechanistically, an increased expression of amino acid transporters and activation of the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway was detected in Nicd/Yap mouse liver tumors. Significantly, the genetic deletion of Raptor, the major mTORC1 component, completely suppressed iCCA development in Nicd/Yap mice. Elevated expression of Notch1, YAP, amino acid transporters, and members of the mTORC1 pathway was also detected ubiquitously in a collection of human iCCA specimens. Their levels were associated with a poor patient outcome. This study demonstrates that Notch and YAP concomitant activation is frequent in human cholangiocarcinogenesis. Notch and YAP synergize to promote iCCA formation by activating the mTORC1 pathway.

Nuclear PTEN and p53 suppress stress-induced liver cancer through distinct mechanisms

PTEN and p53 are highly mutated in many cancers. These two tumor suppressors have critical functions in the nucleus, such as DNA repair, cell cycle progression, and genome maintenance. However, the in vivo functional relationship of nuclear PTEN and p53 is unknown. Here, we analyzed the liver of mice in which nuclear PTEN and p53 are individually or simultaneously depleted. We found that nuclear PTEN loss greatly upregulates p53 expression upon oxidative stress, while the loss of p53 potentiates stress-induced accumulation of PTEN in the nucleus. Next, we examined oxidative stress-induced DNA damage in hepatocytes, and found that nuclear PTEN loss aggravated the damage while p53 loss did not. Notably, mice lacking nuclear PTEN had increased hepatocellular carcinoma under oxidative stress, while mice lacking p53 in hepatocytes had accelerated hepatocellular carcinoma and intrahepatic cholangiocarcinoma. The formation of cholangiocarcinoma appears to involve the transformation of hepatocytes into cholangiocarcinoma. Simultaneous loss of nuclear PTEN and p53 exacerbated both types of liver cancers. These data suggest that nuclear PTEN and p53 suppress liver cancers through distinct mechanisms.

Notch Signaling Regulation in HCC: From Hepatitis Virus to Non-Coding RNAs

The Notch family includes evolutionary conserved genes that encode for single-pass transmembrane receptors involved in stem cell maintenance, development and cell fate determination of many cell lineages. Upon activation by different ligands, and depending on the cell type, Notch signaling plays pleomorphic roles in hepatocellular carcinoma (HCC) affecting neoplastic growth, invasion capability and stem like properties. A specific knowledge of the deregulated expression of each Notch receptor and ligand, coupled with resultant phenotypic changes, is still lacking in HCC. Therefore, while interfering with Notch signaling might represent a promising therapeutic approach, the complexity of Notch/ligands interactions and the variable consequences of their modulations raises concerns when performed in undefined molecular background. The gamma-secretase inhibitors (GSIs), representing the most utilized approach for Notch inhibition in clinical trials, are characterized by important adverse effects due to the non-specific nature of GSIs themselves and to the lack of molecular criteria guiding patient selection. In this review, we briefly summarize the mechanisms involved in Notch pathway activation in HCC supporting the development of alternatives to the γ-secretase pan-inhibitor for HCC therapy.