Human MUC1 oncoprotein regulates p53-responsive gene transcription in the genotoxic stress response

Influence of Escherichia coli infection on intestinal mucosal barrier integrity of germ-free piglets

AIMS

We focused on investigating the influence of Escherichia coli (E. coli) on the intestinal barrier.

MATERIAL AND METHODS

We studied changes in the distribution and secretory activities of goblet cells and enteroendocrine cells (EECs), as well as changes in the population of mast cells (MCs) in the jejunal and colonic mucosa of germ-free (GF) piglets as a healthy control group and GF piglets whose intestines were colonised with E. coli bacteria on day 5.

KEY FINDINGS

The results suggest that the colon of GF piglets is more resistant and less prone to coliform bacterial infection compared to the jejunum. This can be confirmed by a lower degree of histopathological injury index as well as an improvement of the morphometric parameters of the colonic mucosa, together with a significantly increased (p < 0.05) expression of MUC1/EMA, and ZO-3. We also observed a significant decrease in the population of activated MCs (p < 0.001) and EECs (p < 0.001). These findings may indicate a rapid response and better preparation of the intestinal barrier for possible pathological attacks and the subsequent development of mucosal lesions during the development and progression of the intestinal diseases.

SIGNIFICANCE

To date, gut-targeted therapeutic approaches that can modulate bacterial translocation and chronic inflammation are still in their infancy but represent one of the most promising areas of research for the development of new effective treatments or clinical strategies in the future. Therefore, a better understanding of these processes can significantly contribute to the development of these targeted strategies for disease prevention and treatment.

The multifaceted role of MUC1 in tumor therapy resistance

Tumor therapeutic resistances are frequently linked to the recurrence and poor prognosis of cancers and have been a key bottleneck in clinical tumor treatment. Mucin1 (MUC1), a heterodimeric transmembrane glycoprotein, exhibits abnormally overexpression in a variety of human tumors and has been confirmed to be related to the formation of therapeutic resistance. In this review, the multifaceted roles of MUC1 in tumor therapy resistance are summarized from aspects of pan-cancer principles shared among therapies and individual mechanisms dependent on different therapies. Concretely, the common mechanisms of therapy resistance across cancers include interfering with gene expression, promoting genome instability, modifying tumor microenvironment, enhancing cancer heterogeneity and stemness, and activating evasion and metastasis. Moreover, the individual mechanisms of therapy resistance in chemotherapy, radiotherapy, and biotherapy are introduced. Last but not least, MUC1-involved therapy resistance in different types of cancers and MUC1-related clinical trials are summarized.

Galectin-3 and Epithelial MUC1 Mucin-Interactions Supporting Cancer Development

Aberrant glycosylation of cell surface proteins is a very common feature of many cancers. One of the glycoproteins, which undergoes specific alterations in the glycosylation of tumor cells is epithelial MUC1 mucin, which is highly overexpressed in the malignant state. Such changes lead to the appearance of tumor associated carbohydrate antigens (TACAs) on MUC1, which are rarely seen in healthy cells. One of these structures is the Thomsen-Friedenreich disaccharide Galβ1-3GalNAc (T or TF antigen), which is typical for about 90% of cancers. It was revealed that increased expression of the T antigen has a big impact on promoting cancer progression and metastasis, among others, due to the interaction of this antigen with the β-galactose binding protein galectin-3 (Gal-3). In this review, we summarize current information about the interactions between the T antigen on MUC1 mucin and Gal-3, and their impact on cancer progression and metastasis.

Proteome balance in ciliopathies: the OFD1 protein example

The balance of protein synthesis and degradation is finely regulated and influences cellular homeostasis and biological processes (e.g., embryonic development and neuronal plasticity). Recent data demonstrated that centrosomal/ciliary proteins enable proteome control in response to spatial or microenvironmental stimuli. Here, we discuss recent discoveries regarding the role in the balance of the proteome of centrosomal/ciliary proteins associated with genetic disorders known as ciliopathies. In particular, OFD1 was the first example of a ciliopathy protein controlling both protein expression and autophagic/proteasomal degradation. Understanding the role of proteome balance in the pathogenesis of the clinical manifestations of ciliopathies may pave the way to the identification of a wide range of putative novel therapeutic targets for these conditions.

Mechanism and function of miR-140 in human cancers: A review and in silico study

MicroRNA-140 (miR-140) acts as a tumor suppressor and plays a vital role in cell biological functions such as cell proliferation, apoptosis, and DNA repair. The expression of this miRNA has been shown to be considerably decreased in cancer tissues and cell lines compared with normal adjacent tissues. Consequently, aberrant expression of some miR-140 target genes can lead to the initiation and progression of various human cancers, such as breast cancer, gastrointestinal cancers, lung cancer, and prostate cancer. The dysregulation of the miR-140 network also affects cell proliferation, invasion, metastasis, and apoptosis of cancer cells by affecting various signaling pathways. Besides, up-regulation of miR-140 could enhance the efficacy of chemotherapeutic agents in different cancer. We aimed to cover most aspects of miR-140 function in cancer development and address its importance in different stages of cancer progression.

Addiction of Merkel cell carcinoma to MUC1-C identifies a potential new target for treatment

Merkel cell carcinoma (MCC) is an aggressive malignancy with neuroendocrine (NE) features, limited treatment options, and a lack of druggable targets. There is no reported involvement of the MUC1-C oncogenic protein in MCC progression. We show here that MUC1-C is broadly expressed in MCCs and at higher levels in Merkel cell polyomavirus (MCPyV)-positive (MCCP) relative to MCPyV-negative (MCCN) tumors. Our results further demonstrate that MUC1-C is expressed in MCCP, as well as MCCN, cell lines and regulates common sets of signaling pathways related to RNA synthesis, processing, and transport in both subtypes. Mechanistically, MUC1-C (i) interacts with MYCL, which drives MCC progression, (ii) is necessary for expression of the OCT4, SOX2, KLF4, MYC, and NANOG pluripotency factors, and (iii) induces the NEUROD1, BRN2 and ATOH1 NE lineage dictating transcription factors. We show that MUC1-C is also necessary for MCCP and MCCN cell survival by suppressing DNA replication stress, the p53 pathway, and apoptosis. In concert with these results, targeting MUC1-C genetically and pharmacologically inhibits MCC self-renewal capacity and tumorigenicity. These findings demonstrate that MCCP and MCCN cells are addicted to MUC1-C and identify MUC1-C as a potential target for MCC treatment.

Chromosome 1 instability in multiple myeloma: Aberrant gene expression, pathogenesis, and potential therapeutic target

Multiple myeloma (MM), the terminally differentiated B cells malignancy, is widely considered to be incurable since many patients have either developed drug resistance or experienced an eventual relapse. To develop precise and efficient therapeutic strategies, we must understand the pathogenesis of MM. Thus, unveiling the driver events of MM and its further clonal evolution will help us understand this complicated disease. Chromosome 1 instabilities are the most common genomic alterations that participate in MM pathogenesis, and these aberrations of chromosome 1 mainly include copy number variations and structural changes. The chromosome 1q gains/amplifications and 1p deletions are the most frequent structural changes of chromosomes in MM. In this review, we intend to focus on the genes that are affected by chromosome 1 instability: some tumor suppressors were lost or down regulated in 1p deletions, and others that contributed to tumorigenesis were upregulated in 1q gains/amplifications. We have summarized their biological function as well as their roles in the MM pathogenesis, hoping to uncover potential novel therapeutical targets and promote the development of future therapeutic approaches.

MUC1 is a potential target to overcome trastuzumab resistance in breast cancer therapy

Although resistance is its major obstacle in cancer therapy, trastuzumab is the most successful agent in treating epidermal growth factor receptor 2 positive (HER2 +) breast cancer (BC). Some patients show resistance to trastuzumab, and scientists want to circumvent this problem. This review elaborately discusses possible resistance mechanisms to trastuzumab and introduces mucin 1 (MUC1) as a potential target efficient for overcoming such resistance. MUC1 belongs to the mucin family, playing the oncogenic/mitogenic roles in cancer cells and interacting with several other oncogenic receptors and pathways, such as HER2, β-catenin, NF-κB, and estrogen receptor (ERα). Besides, it has been established that MUC1- Cytoplasmic Domain (MUC1-CD) accelerates the development of resistance to trastuzumab and that silencing MUC1-C proto-oncogene is associated with increased sensitivity of HER2⁺ cells to trastuzumab-induced growth inhibitors. We mention why targeting MUC1 can be useful in overcoming trastuzumab resistance in cancer therapy.

Mucinous metaplasia in Pten conditional knockout mice and mucin family genes as prognostic markers for prostate cancer

AIMS

This study evaluated the association of mucinous metaplasia (MM) with tumor cell proliferation, androgen receptor (AR) expression and invasiveness in Pten conditional knockout mice and the prognostic value of MM markers for patients with PCa.

MAIN METHODS

Prostatic lobes samples from genetic engineered mouse model Pten^f/f and Pb-Cre4/Pten^f/f were submitted for histopathological analysis and tissue expression of AR, the proliferation marker Ki67, alpha-smooth muscle actin, and laminin. RNAseq data of prostatic lobes samples were analyzed searching for MM gene expression patterns. We also investigated gene and protein expression related to MM in human PCa public databases.

KEY FINDINGS

All knockout animals analyzed showed at least one area of stroma-invading MM, which was absent in the control animals. The tumoral regions of MM showed a proliferative index 5 times higher than other tumoral areas and low expression of the AR (less than 20% of the cells were AR-positive). Disrupted basement membrane areas were observed in MM. The mouse and human PCa transcriptomes exhibited increased expression of the MM markers such as MUC1, MUC19, MUC4, MUC5AC, MUC5B, and TFF3. Gene expression profile was associated with castration-resistant prostate cancer (CRPC) and with a lower probability of freedom from biochemical recurrence.

SIGNIFICANCE

The expression of goblet cell genes, such as MUC1, MUC5AC, MUC5B, and TFF3 have significant prognostic value for PCa patients and represent another class of potential therapeutic targets.

Biology, Significance and Immune Signaling of Mucin 1 in Hepatocellular Carcinoma

Mucin 1 (MUC 1) is a highly glycosylated tumor-associated antigen (TAA) overexpressed in hepatocellular carcinoma (HCC). This protein plays a critical role in various immune-mediated signaling pathways at its transcriptional and post-transcriptional levels, leading to immune evasion and metastasis in HCC. HCC cells maintain an immune-suppressive environment with the help of immunesuppressive tumor-associated antigens, resulting in a metastatic spread of the disease. The development of intense immunotherapeutic strategies to target tumor-associated antigen is critical to overcoming the progression of HCC. MUC 1 remains the most recognized tumor-associated antigen since its discovery over 30 years ago. A few promising immunotherapies targeting MUC 1 are currently under clinical trials, including CAR-T and CAR-pNK-mediated therapies. This review highlights the biosynthesis, significance, and clinical implication of MUC 1 as an immune target in HCC.

MUC1-C Contributes to the Maintenance of Human Embryonic Stem Cells and Promotes Somatic Cell Reprogramming

Mucin 1 (MUC1) is a transmembrane glycoprotein overexpressed in several cancer cells in which it regulates cell surface properties, tumor invasion, and cell death. Recently, we reported that MUC1-C, the C-terminal subunit of MUC1, is involved in the growth of mouse embryonic stem (ES) cells. However, the functional significance of MUC1-C in human ES cells remains unclear. In this study, we investigated the expression and function of MUC1-C in human ES cells. Based on reverse transcription-polymerase chain reaction, western blotting, and confocal microscopy following immunostaining, undifferentiated human ES cells expressed MUC1-C and the expression level decreased during differentiation. Inhibition of MUC1-C, by the peptide inhibitor GO201 that targets the cytoplasmic domain of MUC1-C (MUC1-CD), reduced cell proliferation and OCT4 protein expression, and promoted cell death. Moreover, the inhibition of MUC1-C increased the intracellular reactive oxygen species (ROS) levels and downregulated expression of glycolysis-related enzymes. These findings indicate that expression and function of MUC1-C are required for stem cell properties involved in cell proliferation, maintenance of pluripotency and optimal ROS levels, and a high glycolytic flux in human ES cells. In addition, forced overexpression of MUC1-CD increased the efficiency of reprogramming from fibroblast cells to induced pluripotent stem cells, suggesting that MUC1-C expression can contribute to the reprogramming process.

The sialidase NEU1 directly interacts with the juxtamembranous segment of the cytoplasmic domain of mucin-1 to inhibit downstream PI3K-Akt signaling

The extracellular domain (ED) of the membrane-spanning sialoglycoprotein, mucin-1 (MUC1), is an in vivo substrate for the lysosomal sialidase, neuraminidase-1 (NEU1). Engagement of the MUC1-ED by its cognate ligand, Pseudomonas aeruginosa-expressed flagellin, increases NEU1-MUC1 association and NEU1-mediated MUC1-ED desialylation to unmask cryptic binding sites for its ligand. However, the mechanism(s) through which intracellular NEU1 might physically interact with its surface-expressed MUC1-ED substrate are unclear. Using reciprocal coimmunoprecipitation and in vitro binding assays in a human airway epithelial cell system, we show here that NEU1 associates with the MUC1-cytoplasmic domain (CD) but not with the MUC1-ED. Prior pharmacologic inhibition of the NEU1 catalytic activity using the NEU1-selective sialidase inhibitor, C9-butyl amide-2-deoxy-2,3-dehydro-N-acetylneuraminic acid, did not diminish NEU1-MUC1-CD association. In addition, glutathione-S-transferase (GST) pull-down assays using the deletion mutants of the MUC1-CD mapped the NEU1-binding site to the membrane-proximal 36 aa of the MUC1-CD. In a cell-free system, we found that the purified NEU1 interacted with the immobilized GST-MUC1-CD and the purified MUC1-CD associated with the immobilized 6XHis-NEU1, indicating that the NEU1-MUC1-CD interaction was direct and independent of its chaperone protein, protective protein/cathepsin A. However, the NEU1-MUC1-CD interaction was not required for the NEU1-mediated MUC1-ED desialylation. Finally, we demonstrated that overexpression of either WT NEU1 or a catalytically dead NEU1 G68V mutant diminished the association of the established MUC1-CD binding partner, PI3K, to MUC1-CD and reduced downstream Akt kinase phosphorylation. These results indicate that NEU1 associates with the juxtamembranous region of the MUC1-CD to inhibit PI3K-Akt signaling independent of NEU1 catalytic activity.

Mucin1 and Mucin16: Therapeutic Targets for Cancer Therapy

The mucin (MUC) family is a group of highly glycosylated macromolecules that are abundantly expressed in mammalian epithelial cells. MUC proteins contribute to the formation of the mucus barrier and thus have protective functions against infection. Interestingly, some MUC proteins are aberrantly expressed in cancer cells and are involved in cancer development and progression, including cell growth, proliferation, the inhibition of apoptosis, chemoresistance, metabolic reprogramming, and immune evasion. With their unique biological and structural features, MUC proteins have been considered promising therapeutic targets and also biomarkers for human cancer. In this review, we discuss the biological roles of the transmembrane mucins MUC1 and MUC16 in the context of hallmarks of cancer and current efforts to develop MUC1- and MUC16-targeted therapies.

A network-based systems biology approach for identification of shared Gene signatures between male and female in COVID-19 datasets

The novel coronavirus (SARS-CoV-2) has expanded rapidly worldwide. Now it has covered more than 150 countries worldwide. It is referred to as COVID-19. SARS-CoV-2 mainly affects the respiratory systems of humans that can lead up to serious illness or even death in the presence of different comorbidities. However, most COVID-19 infected people show mild to moderate symptoms, and no medication is suggested. Still, drugs of other diseases have been used to treat COVID-19. Nevertheless, the absence of vaccines and proper drugs against the COVID-19 virus has increased the mortality rate. Albeit sex is a risk factor for COVID-19, none of the studies considered this risk factor for identifying biomarkers from the RNASeq count dataset. Men are more likely to undertake severe symptoms with different comorbidities and show greater mortality compared with women. From this standpoint, we aim to identify shared gene signatures between males and females from the human COVID-19 RNAseq count dataset of peripheral blood cells using a robust voom approach. We identified 1341 overlapping DEGs between male and female datasets. The gene ontology (GO) annotation and pathway enrichment analysis revealed that DEGs are involved in various BP categories such as nucleosome assembly, DNA conformation change, DNA packaging, and different KEGG pathways such as cell cycle, ECM-receptor interaction, progesterone-mediated oocyte maturation, etc. Ten hub-proteins (UBC, KIAA0101, APP, CDK1, SUMO2, SP1, FN1, CDK2, E2F1, and TP53) were unveiled using PPI network analysis. The top three miRNAs (mir-17-5p, mir-20a-5p, mir-93-5p) and TFs (PPARG, E2F1 and KLF5) were uncovered. In conclusion, the top ten significant drugs (roscovitine, curcumin, simvastatin, fulvestrant, troglitazone, alvocidib, L-alanine, tamoxifen, serine, and doxorubicin) were retrieved using drug repurposing analysis of overlapping DEGs, which might be therapeutic agents of COVID-19.

Mucin in cancer: a stealth cloak for cancer cells

Mucins are high molecular-weight epithelial glycoproteins and are implicated in many physiological processes, including epithelial cell protection, signaling transduction, and tissue homeostasis. Abnormality of mucus expression and structure contributes to biological properties related to human cancer progression. Tumor growth sites induce inhospitable conditions. Many kinds of research suggest that mucins provide a microenvironment to avoid hypoxia, acidic, and other biological conditions that promote cancer progression. Given that the mucus layer captures growth factors or cytokines, we propose that mucin helps to ameliorate inhospitable conditions in tumor-growing sites. Additionally, the composition and structure of mucins enable them to mimic the surface of normal epithelial cells, allowing tumor cells to escape from immune surveillance. Indeed, human cancers such as mucinous carcinoma, show a higher incidence of invasion to adjacent organs and lymph node metastasis than do non-mucinous carcinoma. In this mini-review, we discuss how mucin provides a tumor-friendly environment and contributes to increased cancer malignancy in mucinous carcinoma.

MUC1 is an oncoprotein with a significant role in apoptosis (Review)

Mucin 1 (MUC1) is a membrane-bound, highly glycosylated protein that is overexpressed in all stages of malignant transformation. Overexpression of MUC1 together with loss of polarization and hypoglycosylation are associated with resistance to apoptosis, which is the process that results in efficient removal of damaged cells. Inhibition of the apoptotic process is responsible for tumor development, tumor progression and drug resistance. MUC1 is considered as an oncogenic molecule that is involved in various signaling pathways responsible for the regulation of apoptosis. Based on this, the aim of the present study was to discuss the involvement of MUC1 in the divergent mechanisms regulating programmed cell death.

Combined Action of Anti-MUC1 Monoclonal Antibody and Pyrazole-Platinum(II) Complexes Reveals Higher Effectiveness towards Apoptotic Response in Comparison with Monotherapy in AGS Gastric Cancer Cells

MUC1 mucin is a transmembrane glycoprotein aberrantly overexpressed and underglycosylated in most epithelium origin cancers. Combining chemotherapeutics with monoclonal antibodies toward cancer-related antigens is one of the new strategies in cancer therapies. In this study, we assessed the effectiveness of 10 μM cisplatin (cisPt), two pyrazole-platinum(II) complexes (PtPz4 and PtPz6), and 5 μg/mL anti-MUC1 used as monotherapy, as well as cisplatin and its derivatives combined with mAb on apoptotic response and specific cancer-related sugar antigens in AGS gastric cancer cells. Flow cytometry, RT-PCR, Western blotting, and ELISA tests were applied to determine the influence of examined compounds on analyzed factors. PtPz6 combined with anti-MUC1 revealed the strongest apoptotic response compared to control and monotherapy. The combined action of both cisPt derivatives and anti-MUC1 was more effective than monotherapy in relation to Bad, Bcl-xL, Bcl-2, caspase-9, caspase-3, as well as pro- and cleaved caspase-3 protein, and T, sialyl Tn sugar antigens in cell lysates, and Tn, T, sialyl Tn, sialyl T antigens in culture medium. Additionally, PtPz4 administrated with mAb was revealed to be more potent than used alone with regard to Bax protein and Bid expression, and PtPz6 used in complex with anti-MUC1 revealed more efficient action towards Akt and sialyl T antigen expression. These data indicate the rationality of the potential application of combined treatment of anti-MUC1 and cisPt derivatives in gastric cancer therapy.

Metabolic Control by DNA Tumor Virus-Encoded Proteins

Viruses co-opt a multitude of host cell metabolic processes in order to meet the energy and substrate requirements for successful viral replication. However, due to their limited coding capacity, viruses must enact most, if not all, of these metabolic changes by influencing the function of available host cell regulatory proteins. Typically, certain viral proteins, some of which can function as viral oncoproteins, interact with these cellular regulatory proteins directly in order to effect changes in downstream metabolic pathways. This review highlights recent research into how four different DNA tumor viruses, namely human adenovirus, human papillomavirus, Epstein-Barr virus and Kaposi's associated-sarcoma herpesvirus, can influence host cell metabolism through their interactions with either MYC, p53 or the pRb/E2F complex. Interestingly, some of these host cell regulators can be activated or inhibited by the same virus, depending on which viral oncoprotein is interacting with the regulatory protein. This review highlights how MYC, p53 and pRb/E2F regulate host cell metabolism, followed by an outline of how each of these DNA tumor viruses control their activities. Understanding how DNA tumor viruses regulate metabolism through viral oncoproteins could assist in the discovery or repurposing of metabolic inhibitors for antiviral therapy or treatment of virus-dependent cancers.

Crosstalk between MUC1 and VEGF in angiogenesis and metastasis: a review highlighting roles of the MUC1 with an emphasis on metastatic and angiogenic signaling

VEGF and its receptor family (VEGFR) members have unique signaling transduction system that play significant roles in most pathological processes, such as angiogenesis in tumor growth and metastasis. VEGF-VEGFR complex is a highly specific mitogen for endothelial cells and any de-regulation of the angiogenic balance implicates directly in endothelial cell proliferation and migration. Moreover, it has been shown that overexpressing Mucin 1 (MUC1) on the surface of many tumor cells resulting in upregulation of numerous signaling transduction cascades, such as growth and survival signaling pathways related to RTKs, loss of cell-cell and cell-matrix adhesion, and EMT. It promotes gene transcription of pro-angiogenic proteins such as HIF-1α during periods of oxygen scarcity (hypoxia) to enhance tumor growth and angiogenesis stimulation. In contrast, the cytoplasmic domain of MUC1 (MUC1-C) inhibits apoptosis, which in turn, impresses upon cell fate. Besides, it has been established that reduction in VEGF expression level correlated with silencing MUC1-C level indicating the anti-angiogenic effect of MUC1 downregulation. This review enumerates the role of MUC1-C oncoprotein and VEGF in angiogenesis and metastasis and describes several signaling pathways by which MUC1-C would mediate the pro-angiogenic activities of cancer cells.

Inhibition of MUC1-C Increases ROS and Cell Death in Mouse Embryonic Stem Cells

Background and Objectives

Embryonic stem (ES) cells have the capacity to self-renew and generate all types of cells. MUC1-C, a cytoplasmic subunit of MUC1, is overexpressed in various carcinomas and mediates signaling pathways to regulate intracellular metabolic processes and gene expression involved in the maintenance of cancer cells. However, the functional role of MUC1-C in ES cells is not well understood. In this study, we investigated the role of MUC1-C on growth, survival, and differentiation of mouse ES (mES) cells.

Methods and Results

Undifferentiated mES cells expressed the MUC1-C protein and the expression level was decreased during differentiation. Inhibition of MUC1-C, by the specific inhibitor GO201, reduced proliferation of mES cells. However, there was no prominent effect on pluripotent markers such as Oct4 expression and STAT3 signaling, and MUC1-C inhibition did not induce differentiation. Inhibition of MUC1-C increased the G1 phase population, decreased the S phase population, and increased cell death. Furthermore, inhibition of MUC1-C induced disruption of the ROS balance in mES cells.

Conclusions

These results suggest that MUC1-C is involved in the growth and survival of mES cells.

Matrix Metalloprotease-7 Mediates Nucleolar Assembly and Intra-nucleolar Cleaving p53 in Gefitinib-Resistant Cancer Stem Cells

The enlarged distinct bulky-ball-like nucleolus matrix assembly is observed in most cancer stem cells (CSCs); however, the underlying mechanism is largely unknown. We show that matrix metalloproteinase-7 (MMP-7) shedding MUC-1 SEA domain releases MUC-1 C-ter, facilitating the nucleolus trafficking of p53 in gefitinib-resistant lung CSCs. The nucleolus colocalizations of p53, MUC-1 C-ter, MMP-7 and nucleolin were observed in the CD34⁺ CXADR⁺ CD44v₃⁺ gefitinib-resistant EGFR^L858R/T790M CSC colonies. MUC-1 C-ter induced a unique porous bulky-ball-shaped, cagelike nucleolus that functions as a nucleus molecular “garage” for potent tumor suppressor, p53. Nucleolus could also facilitate the novel sub-nucleus compartment for proteolytic processing p53 by MMP-7 to generate a 35 kDa fragment. Moreover, we show that salinomycin, an anti-CSC agent, disrupts nucleolus by inducing nucleoplasm translocation of p53 and sensitizing CSC to chemotherapy drugs. Thus, this study highlights the MMP-7-MUC-1-p53 axis in nucleolus as a potential therapeutic target for anti-CSCs to resolve the chemotherapy-resistance dilemma.

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MMP-7 cleaves the SEA domain of MUC-1 and releases MUC-1 C-ter

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MUC-1 C-ter mediates bulky-ball-like nucleolus assembly trapping p53 in nucleolus

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MMP-7 cleaves p53 to 35 kDa fragments in the nucleolus of gefitinib-resistant CSCs

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Salinomycin induces p53 nucleoplasm translocation sensitizing CSCs to gefitinib

Quercetin and MicroRNA Interplay in Apoptosis Regulation in Ovarian Cancer

The multifaceted nature of ovarian cancer has severely hampered the development of effective therapeutics over the years. The complicate nature of ovarian cancer makes it therapeutically challenging, therefore, there has been a renewed interest in phytochemistry. Phytochemicals have emerged as a potential therapeutic option due to less side effects. Moreover, the signaling inhibition properties have also been studied extensively in recent times. A growing number of data obtained via high-throughput technologies has started to delineate the complex oncogenic signaling networks, thus broadening the therapeutic opportunities. Within the network, microRNAs (miRNAs) have been shown to play a versatile role in the regulation of cancer. Quercetin has been in the spotlight over the years because of its high pharmacological values and substantial evidence has demonstrated its anti-proliferative effect against various types of cancers. Despite the versatility of quercetin, little is known about its anti-proliferative potential towards ovarian cancer. This review sheds some light on quercetin as an alternative therapeutic approach to cancer. Furthermore, we also addresss the interplay between miRNAs and quercetin in the regulation of apoptosis in ovarian cancer.

Integrated Bioinformatics analysis and clinical validation reveals that high expression of mucin 1 in intrahepatic cholangiocarcinoma predicts recurrence after curative resection

Intrahepatic cholangiocarcinoma (ICC) is a cancer type with high malignancy and a current lack of biomarkers to predict recurrence. In the present study, to identify potential biomarkers, five ICC datasets from the Gene Expression Omnibus database were analyzed to construct initial datasets by using a robust rank aggregation approach. A total of 19 upregulated genes were identified in the initial datasets. The genes identified were then further analysed using data from The Cancer Genome Atlas. Only mucin 1 (MUC1) exhibited significance regarding differential expression and survival prediction. Finally, the expression levels of MUC1 were assessed using reverse transcription-quantitative PCR in 61 pairs of ICC tumor and matched non-cancerous samples. The expression of MUC1 was significantly elevated in ICC tissues compared with that in matched non-cancerous counterparts (P=0.001). Patients with high MUC1 expression levels had significantly shorter overall survival (OS, P=0.009) and recurrence-free survival (RFS, P=0.012). MUC1 was identified as an independent prognostic factor for OS [hazard ratio (HR)=2.364, 95%CI: 1.214-4.485; P=0.023] and RFS (HR=2.552 95%CI: 1.294-5.032; P=0.007) in the multivariate analysis. Using receiver operating characteristic analysis, a co-index including MUC1 had a high accuracy for predicting survival [MUC1 combined with serum levels of CEA and cancer antigen 19-9, and lymph node metastasis, area under curve (AUC)=0.746, 95%CI: 0.620-0.872] and recurrence (MUC1 combined with bile duct invasion and lymph node metastasis, AUC=0.729, 95%CI: 0.605-854). In conclusion, MUC1 is highly expressed in ICC tissue and is a potential prognostic biomarker and therapeutic target for ICC.

Novel Antibodies Targeting MUC1-C Showed Anti-Metastasis and Growth-Inhibitory Effects on Human Breast Cancer Cells

Mucin1 (MUC1) is aberrantly glycosylated and overexpressed in various cancers, and it plays a crucial role in cancerogenesis. MUC1 is a type I membranous protein composed of α and β subunits. MUC1-α can be cleaved in cancers, exposing MUC1-β (MUC1-C). MUC1-C is involved with multiple cancer cellular functions, which makes it an attractive target for cancer treatment. However, its multifunctional mechanisms have not been fully elucidated and there has not been a successful therapeutic development against MUC1-C. Through a phage display process, we isolated the specific antibodies for the extracellular domain of MUC1-C. The relevant full IgG antibodies were produced successfully from mammalian cells and validated for their MUC1-C specificities through ELISA, dual FACS analysis, BLI assay, and confocal image analysis. In the comparison with reference antibody, elected antibodies showed characteristic bindings on target antigens. In the functionality assessment of high-ranking antibodies, SKM1-02, -13, and -20 antibodies highly inhibited invasion by triple-negative breast cancer (TNBC) cells and the SKM1-02 showed strong growth inhibition of cancer cells. Our results showed that these MUC1-C specific antibodies will be important tools for the understanding of MUC1 oncogenesis and are also highly effective therapeutic candidates against human breast cancers, especially TNBC cells.

Peritoneal Metastases in Colorectal Cancer: Biology and Barriers

BACKGROUND

Advances in the molecular biology of tumor metastasis have paralleled the evolution in the management of metastatic disease from colorectal cancer. In this review, we summarize the current understanding of the mechanism of colorectal cancer metastases, in particular that of peritoneal metastases, as well as clinical data on the treatment of this disease.

METHODS

A review of relevant English literature using MEDLINE/PubMed on the biology of colorectal cancer metastases, determinants of oligometastasis, and use of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in the treatment of metastatic colorectal cancer is presented.

RESULTS

Recognition of oligometastasis in the evolution of colorectal peritoneal metastases provides the theoretical framework for which cytoreductive surgery with or without hyperthermic intraperitoneal chemotherapy is considered. Clearly, a subset of patients benefit from peritoneal metastasectomy.

CONCLUSION

Advances in cancer biology and clinical imaging promise to expand the role of cytoreductive surgery with or without intraperitoneal chemotherapy in the management of peritoneal metastases from colorectal cancer.

MUC1 oncoprotein mitigates ER stress via CDA-mediated reprogramming of pyrimidine metabolism

The Mucin 1 (MUC1) protein is overexpressed in various cancers and mediates chemotherapy resistance. However, the mechanism is not fully understood. Given that most chemotherapeutic drugs disrupt ER homeostasis as part of their toxicity, and MUC1 expression is regulated by proteins involved in ER homeostasis, we investigated the link between MUC1 and ER homeostasis. MUC1 knockdown in pancreatic cancer cells enhanced unfolded protein response (UPR) signaling and cell death upon ER stress induction. Transcriptomic analysis revealed alterations in the pyrimidine metabolic pathway and cytidine deaminase (CDA). ChIP and CDA activity assays showed that MUC1 occupied CDA gene promoter upon ER stress induction correlating with increased CDA expression and activity in MUC1-expressing cells as compared to MUC1 knockdown cells. Inhibition of either the CDA or pyrimidine metabolic pathway diminished survival in MUC1-expressing cancer cells upon ER stress induction. Metabolomic analysis demonstrated that MUC1-mediated CDA activity corresponded to deoxycytidine to deoxyuridine metabolic reprogramming upon ER stress induction. The resulting increase in deoxyuridine mitigated ER stress-induced cytotoxicity. Additionally, given 1) the established roles of MUC1 in protecting cells against reactive oxygen species (ROS) insults, 2) ER stress-generated ROS further promote ER stress and 3) the emerging anti-oxidant property of deoxyuridine, we further investigated if MUC1 regulated ER stress by a deoxyuridine-mediated modulation of ROS levels. We observed that deoxyuridine could abrogate ROS-induced ER stress to promote cancer cell survival. Taken together, our findings demonstrate a novel MUC1-CDA axis of the adaptive UPR that provides survival advantage upon ER stress induction.

MUC1-C regulates lineage plasticity driving progression to neuroendocrine prostate cancer

Neuroendocrine prostate cancer (NEPC) is an aggressive malignancy with no effective targeted therapies. The oncogenic MUC1-C protein is overexpressed in castration-resistant prostate cancer (CRPC) and NEPC, but its specific role is unknown. Here, we demonstrate that upregulation of MUC1-C in androgen-dependent PC cells suppresses androgen receptor (AR) axis signaling and induces the neural BRN2 transcription factor. MUC1-C activates a MYC→BRN2 pathway in association with induction of MYCN, EZH2 and NE differentiation markers (ASCL1, AURKA and SYP) linked to NEPC progression. Moreover, MUC1-C suppresses the p53 pathway, induces the Yamanaka pluripotency factors (OCT4, SOX2, KLF4 and MYC) and drives stemness. Targeting MUC1-C decreases PC self-renewal capacity and tumorigenicity, suggesting a potential therapeutic approach for CRPC and NEPC. In PC tissues, MUC1 expression associates with suppression of AR signaling and increases in BRN2 expression and NEPC score. These results highlight MUC1-C as a master effector of lineage plasticity driving progression to NEPC.

Transcriptome profiles of hypothalamus and adrenal gland linked to haplotype related to coping behavior in pigs

The hypothalamic-pituitary-adrenal (HPA) axis is an important component of neuroendocrine stress regulation and coping behavior. Transcriptome profiles of the hypothalamus and adrenal gland were assessed to identify molecular pathways and candidate genes for coping behavior in pigs. Ten each of high- (HR) and low- (LR) reactive pigs (n = 20) were selected for expression profiling based haplotype information of a prominent QTL-region on SSC12 discovered in our previous genome-wide association study (GWAS) on coping behavior. Comparing the HR and LR pigs showed 692 differentially expressed genes (DEGs) in the adrenal gland and 853 DEGs in the hypothalamus, respectively. Interestingly, 47% (17 out of 36) of DEGs found in both tissues were located in GWAS regions identified on SSC12, indicating that there are significant functional positional candidate genes for coping behaviour. Pathway analysis assigned DEGs to glucocorticoid receptor signaling in the adrenal gland. Furthermore, oxidative phosphorylation, mitochondrial dysfunction, and NGF signaling as well as cholecystokinin/Gastrin-mediated were identified in the hypothalamus. We narrowed the list of candidate genes in GWAS regions by analyzing their DEGs in the HPA axis. The top identified transcripts, including ATP1B2, AURKB, MPDU1 and NDEL1 provide evidence for molecular correlates of coping behavior in GWAS regions.

Genetic and molecular bases of esophageal Cancer among Iranians: an update

Abstract

Background

Esophageal cancer is one of the leading causes of cancer related deaths among the Iranians. There is still a high ratio of mortality and low 5 years survival which are related to the late onset and diagnosis. Majority of patients refer for the treatment in advanced stages of tumor progression.

Main body

It is required to define an efficient local panel of diagnostic and prognostic markers for the Iranians. Indeed such efficient specific panel of markers will pave the way to decrease the mortality rate and increase the 5 years survival among the Iranian patients via the early diagnosis and targeted therapy.

Conclusion

in present review we have reported all of the molecular markers in different signaling pathways and cellular processes which have been assessed among the Iranian esophageal cancer patients until now.

MUC1-C represses the RASSF1A tumor suppressor in human carcinoma cells

RASSF1A encodes a tumor suppressor that inhibits the RAS→RAF→MEK→ERK pathway and is one of the most frequently inactivated genes in human cancers. MUC1-C is an oncogenic effector of the cancer cell epigenome that is overexpressed in diverse carcinomas. We show here that MUC1-C represses RASSF1A expression in KRAS wild-type and mutant cancer cells. Mechanistically, MUC1-C occupies the RASSF1A promoter in a complex with the ZEB1 transcriptional repressor. In turn, MUC1-C/ZEB1 complexes recruit DNA methyltransferase 3b (DNMT3b) to the CpG island in the RASSF1A promoter. Targeting MUC1-C, ZEB1 and DNMT3b thereby decreases methylation of the CpG island and derepresses RASSF1A transcription. We also show that targeting MUC1-C regulates KRAS signaling, as evidenced by RNA-seq analysis, and decreases MEK/ERK activation, which is of importance for RAS-mediated tumorigenicity. These findings define a previously unrecognized role for MUC1-C in suppression of RASSF1A and support targeting MUC1-C as an approach for inhibiting MEK→ERK signaling.

MUC1 Story: Great Expectations, Disappointments and the Renaissance

In the course of studying human mucin MUC1, the attitude towards this molecule has been changing time and again. Initially, the list of presumable functions of MUC1 was restricted to protecting and lubricating epithelium. To date, it is assumed to play an important role in cell signaling as well as in all stages of oncogenesis, from malignant cell transformation to tumor dissemination. The story of MUC1 is full of hopes and disappointments. However, the scientific interest to MUC1 has never waned, and the more profoundly it has been investigated, the clearer its hidden potential turned to be disclosed. The therapeutic potential of mucin MUC1 has already been noted by various scientific groups at the early stages of research. Over forty years ago, the first insights into MUC1 functions became a strong ground for considering this molecule as potential target for anticancer therapy. Therefore, this direction of research has always been of particular interest and practical importance. More than 200 papers on MUC1 were published in 2016; the majority of them are dedicated to MUC1-related anticancer diagnostics and therapeutics. Here we review the history of MUC1 studies from the very first attempts to reveal its functions to the ongoing renaissance.

MUC1-C Integrates Chromatin Remodeling and PARP1 Activity in the DNA Damage Response of Triple-Negative Breast Cancer Cells

The oncogenic MUC1-C protein is overexpressed in triple-negative breast cancer (TNBC) cells and contributes to their epigenetic reprogramming and chemoresistance. Here we show that targeting MUC1-C genetically or pharmacologically with the GO-203 inhibitor, which blocks MUC1-C nuclear localization, induced DNA double-strand breaks and potentiated cisplatin (CDDP)-induced DNA damage and death. MUC1-C regulated nuclear localization of the polycomb group proteins BMI1 and EZH2, which formed complexes with PARP1 during the DNA damage response. Targeting MUC1-C downregulated BMI1-induced H2A ubiquitylation, EZH2-driven H3K27 trimethylation, and activation of PARP1. As a result, treatment with GO-203 synergistically sensitized both mutant and wild-type BRCA1 TNBC cells to the PARP inhibitor olaparib. These findings uncover a role for MUC1-C in the regulation of PARP1 and identify a therapeutic strategy for enhancing the effectiveness of PARP inhibitors against TNBC. SIGNIFICANCE: These findings demonstrate that targeting MUC1-C disrupts epigenetics of the PARP1 complex, inhibits PARP1 activity, and is synergistic with olaparib in TNBC cells.

miR-1226 detection in GCF as potential biomarker of chronic periodontitis: A pilot study

Background

The study and identification of new biomarkers for periodontal disease, such as microRNAs (miRNAs), may give us more information about the location and severity of the disease and will serve as a basis for treatment planning and disease-monitoring. miRNAs are a group of small RNAs which are involved in gene regulation by binding to their messenger RNA target (mRNA). In this pilot study, the procedure for purifying miRNAs from gingival crevicular fluid (GCF) was, for the first time, described. In addition, the concentration of miRNAs in GCF was analyzed and compared between patients with moderate or severe chronic periodontitis (CP) and healthy controls.

Material and Methods

GCF samples were collected from single-rooted teeth of patients with moderate or severe CP (n=9) and of healthy individuals (n=9). miRNAs were isolated from GCF using miRNeasy Serum/Plasma kit (Qiagen, CA. USA). Reverse transcription polymerase chain reaction (qRT-PCR) was used to determine the expression of a series of miRNAs candidates that are related to bone metabolism. The significance of differences in miRNA levels between both groups was determined using Mann-Whitney U test.

Results

The results from this pilot study indicate that miRNAs can be isolated from GCF. Six different miRNAs were analyzed (miR-671, miR-122, miR-1306, miR-27a, miR-223, miR-1226), but only miR-1226 showed statically significant differences between the CP group and healthy controls (p<0.05). This miRNA was downregulated in patients with CP.

Conclusions

Within the limitations of the present study, it may be concluded that miR-1226 can be a promising biomarker for periodontal disease, adding relevant information to common clinical parameters used for diagnosis and prognosis of periodontitis.

Key words:Small interfering RNA, biomarkers, periodontal diseases, reverse transcriptase polymerase chain reaction.

MUC1-C activates polycomb repressive complexes and downregulates tumor suppressor genes in human cancer cells

The PRC2 and PRC1 complexes are aberrantly expressed in human cancers and have been linked to decreases in patient survival. MUC1-C is an oncoprotein that is also overexpressed in diverse human cancers and is associated with a poor prognosis. Recent studies have supported a previously unreported function for MUC1-C in activating PRC2 and PRC1 in cancer cells. In the regulation of PRC2, MUC1-C (i) drives transcription of the EZH2 gene, (ii) binds directly to EZH2, and (iii) enhances occupancy of EZH2 on target gene promoters with an increase in H3K27 trimethylation. Regarding PRC1, which is recruited to PRC2 sites in the hierarchical model, MUC1-C induces BMI1 transcription, forms a complex with BMI1, and promotes H2A ubiquitylation. MUC1-C thereby contributes to the integration of PRC2 and PRC1-mediated repression of tumor suppressor genes, such as CDH1, CDKN2A, PTEN and BRCA1. Like PRC2 and PRC1, MUC1-C is associated with the epithelial-mesenchymal transition (EMT) program, cancer stem cell (CSC) state, and acquisition of anticancer drug resistance. In concert with these observations, targeting MUC1-C downregulates EZH2 and BMI1, inhibits EMT and the CSC state, and reverses drug resistance. These findings emphasize the significance of MUC1-C as a therapeutic target for inhibiting aberrant PRC function and reprogramming the epigenome in human cancers.

Single domain based bispecific antibody, Muc1-Bi-1, and its humanized form, Muc1-Bi-2, induce potent cancer cell killing in muc1 positive tumor cells

Muc1 is one of the most studied tumor antigens. However, antibodies or antibody-toxin conjugates against Muc1 have not shown significant efficacy for tumors with Muc1 overexpression. In this study, we employed bispecific antibody approach to target Muc1 positive tumor cells. A novel bispecific antibody, Muc1-Bi-1, was constructed by linking single domain antibodies, anti-Muc1-VHH and anti-CD16-VHH. Muc1-Bi-2, the humanized form of Muc1-Bi-1, was also constructed by grafting. Both Muc1-Bi bispecific antibodies can be efficiently expressed and purified from bacteria. In vitro, the Muc1-Bi bispecific antibodies can recruit Natural Killer (NK) cells to drive potent and specific cell killing of Muc1-overexpressing tumor cells. In xenograft model, the Muc1-Bi bispecific antibodies can suppress tumor growth in the presence of human peripheral blood mononuclear cells (PBMC). These data suggested that the single domain based Muc1-Bi may provide a valid strategy for targeting tumors with Muc1 overexpression.

Peroxisome Proliferator-Activated Receptor γ and PGC-1α in Cancer: Dual Actions as Tumor Promoter and Suppressor

Peroxisome proliferator-activated receptor γ (PPARγ) is part of a nuclear receptor superfamily that regulates gene expression involved in cell differentiation, proliferation, immune/inflammation response, and lipid metabolism. PPARγ coactivator-1α (PGC-1α), initially identified as a PPARγ-interacting protein, is an important regulator of diverse metabolic pathways, such as oxidative metabolism and energy homeostasis. The role of PGC-1α in diabetes, neurodegeneration, and cardiovascular disease is particularly well known. PGC-1α is also now known to play important roles in cancer, independent of the role of PPARγ in cancer. Though many researchers have studied the expression and clinical implications of PPARγ and PGC-1α in cancer, there are still many controversies about the role of PPARγ and PGC-1α in cancer. This review examines and summarizes some recent data on the role and action mechanisms of PPARγ and PGC-1α in cancer, respectively, particularly the recent progress in understanding the role of PPARγ in several cancers since our review was published in 2012.

Identification of FRA-1 as a novel player in pancreatic cancer in cooperation with a MUC1: ERK signaling axis

The MUC1 glycoprotein is overexpressed and aberrantly glycosylated in >90% of pancreatic ductal adenocarcinoma cases and impacts tumor progression by initiating downstream signaling through phosphorylation of its cytoplasmic tail. Previous studies have demonstrated that MUC1 alters expression of known targets of activator protein 1 (AP-1); however, no studies have evaluated the precise impact of MUC1 signaling on the activity and formation of AP-1. Given the known role of these proteins in modulating migration, invasion, and tumor progression, we explored the effects of MUC1 on AP-1 dimer formation and function. We determined that MUC1 increased the protein levels of c-Jun, the major component of AP-1, and promoted dimerization of c-Jun with the Fos-protein FRA-1. We demonstrate that FRA-1 acts as a potent mediator of migration and invasion in a manner that is modulated by signals through MUC1, which acts as a dominant regulator of specific AP-1 and FRA-1 target genes. Our results provide the first in vivo evidence of a FRA-1 mediated expression profile that impacts pancreatic tumor growth properties. In summary, we show that MUC1 enhancement of ERK activation influences FRA-1 activity to modulate tumor migration, invasion and metastasis in a subset of pancreatic cancer cases.

Implication of Soluble Forms of Cell Adhesion Molecules in Infectious Disease and Tumor: Insights from Transgenic Animal Models

Cell adhesion molecules (CAMs) are surface ligands, usually glycoproteins, which mediate cell-to-cell adhesion. They play a critical role in maintaining tissue integrity and mediating migration of cells, and some of them also act as viral receptors. It has been known that soluble forms of the viral receptors bind to the surface glycoproteins of the viruses and neutralize them, resulting in inhibition of the viral entry into cells. Nectin-1 is one of important CAMs belonging to immunoglobulin superfamily and herpesvirus entry mediator (HVEM) is a member of the tumor necrosis factor (TNF) receptor family. Both CAMs also act as alphaherpesvirus receptor. Transgenic mice expressing the soluble form of nectin-1 or HVEM showed almost complete resistance against the alphaherpesviruses. As another CAM, sialic acid-binding immunoglobulin-like lectins (Siglecs) that recognize sialic acids are also known as an immunoglobulin superfamily member. Siglecs play an important role in the regulation of immune cell functions in infectious diseases, inflammation, neurodegeneration, autoimmune diseases and cancer. Siglec-9 is one of Siglecs and capsular polysaccharide (CPS) of group B Streptococcus (GBS) binds to Siglec-9 on neutrophils, leading to suppress host immune response and provide a survival advantage to the pathogen. In addition, Siglec-9 also binds to tumor-produced mucins such as MUC1 to lead negative immunomodulation. Transgenic mice expressing the soluble form of Siglec-9 showed significant resistance against GBS infection and remarkable suppression of MUC1 expressing tumor proliferation. This review describes recent developments in the understanding of the potency of soluble forms of CAMs in the transgenic mice and discusses potential therapeutic interventions that may alter the outcomes of certain diseases.

Mucins: Structural diversity, biosynthesis, its role in pathogenesis and as possible therapeutic targets

Mucins are the main structural components of mucus that create a selective protective barrier for epithelial surface and also execute wide range of other physiological functions. Mucins can be classified into two types, namely secreted mucins and membrane bounded mucins. Alterations in mucin expression or glycosylation and mislocalization have been seen in various types of pathological conditions such as cancers, inflammatory bowel disease and ocular disease, which highlight the importance of mucin in maintaining homeostasis. Hence mucins can be used as attractive target for therapeutic intervention. In this review, we discuss in detail about the structural diversity of mucins; their biosynthesis; its role in pathogenesis; regulation and as possible therapeutic targets.

Mechanism of anticancer action of novel berenil complex of platinum(II) combined with anti-MUC1 in MCF-7 breast cancer cells

Mucin 1 (MUC1) is a high molecular weight transmembrane glycoprotein, that is overexpressed in >90% of breast cancers. It serves a crucial role in anti-apoptosis and tumor progression. MUC1 interacts with proteins in the extracellular matrix, at the cell membrane, in the cytoplasm and in the nucleus. The aim of the present study was to investigate the mechanism of anticancer action induced by novel berenil complex of platinum(II) (Pt12) together with a monoclonal antibody against MUC1 in breast cancer MCF-7 cells. The effect of combined treatment on the concentration of selected markers of apoptosis including proapoptotic B-cell lymphoma 2 associated X protein (Bax), caspase-8, cytochrome c and caspase-9, as well as selected proteins involved in intracellular signal transduction pathways including p53, phosphoinositide 3-kinase and phosphorylated protein kinase B (p-Akt) were analyzed. The results of the present study demonstrated that combined treatment may be a promising strategy in anticancer treatment and represents an alternative to monotherapy. All compounds used alone (Pt12, cisplatin and the anti-MUC1 antibody) increased the concentration of proapoptotic Bax, cytochrome c and caspase-9 in comparison with control, thus suggesting that they activated the mitochondrial apoptotic pathway. Pt12 alone significantly increased the concentration of caspase-8, which is responsible for the initiation of the extrinsic apoptotic pathway. However, the strongest effect was observed following Pt12 (20 µM) treatment combined with the anti-MUC1 antibody (10 µg/ml). These two compounds together strongly induced apoptosis in MCF-7 breast cancer cells via the external and internal apoptotic pathways. It was also demonstrated that combined treatment based on Pt12 and the anti-MUC1 antibody significantly reduced p-Akt concentration.

Mucin 1 promotes radioresistance in hepatocellular carcinoma cells through activation of JAK2/STAT3 signaling

Mucin 1 (MUC1) is aberrantly overexpressed in numerous human cancer types, including hepatocellular carcinoma (HCC) and contributes to chemoresistance of tumor cells. The aim of the present study was to evaluate the possible implication of MUC1 in radioresistance of HCC cells and the underlying mechanisms. It was demonstrated that MUC1 was significantly upregulated in HCC cells following irradiation exposure, which was coupled with increased phosphorylation of signal transducer and activator of transcription 3 (STAT3). Enforced expression of MUC1 significantly (P<0.05) promoted the clonogenic survival of HCC cells following irradiation compared with empty vector-transfected cells. MUC1 overexpression resulted in >60% reduction in apoptosis induced by irradiation, as determined by Annexin-V/propidium iodide double staining and flow cytometry analysis. Furthermore, overexpression of MUC1 significantly (P<0.05) attenuated the activation of caspase-3 and poly (ADP-ribose) polymerase in response to irradiation exposure. Mechanistically, MUC1 inhibited irradiation-induced apoptosis through activation of janus kinase 2 (JAK2) and STAT3, and induction of anti-apoptotic proteins induced myeloid leukemia cell differentiation protein Mcl-1 (Mcl-1) and BCL2 like 1 (Bcl-xL). Small hairpin RNA-mediated knockdown of STAT3 or MUC1 resensitized MUC1-overexpressing cells to irradiation-induced apoptosis, which was accompanied by reduced expression of Bcl-xL and Mcl-1. Collectively, MUC1 contributes to radioresistance of HCC cells likely through activation of the JAK2/STAT3 signaling pathway and thus represents a potential target for improving radiotherapy against HCC.

Generation and characterization of a monoclonal antibody to the cytoplasmic tail of MUC16

MUC16 is a large transmembrane mucin expressed on the apical surfaces of the epithelium covering the ocular surface, respiratory system and female reproductive tract. The transmembrane mucin is overexpressed by ovarian carcinomas, it is one of the most frequently used diagnostic markers for the disease and it is considered a promising target for immunotherapeutic intervention. Immunodetection of the mucin has to date been through antibodies that recognize its exceptionally large ectodomain. Similar to other membrane anchored mucins, MUC16 has a short cytoplasmic tail (CT), but studies of the biological relevance of the C-terminal domain of MUC16 has been limited by lack of availability of monoclonal antibodies that recognize the native CT. Here, we report the development of a novel monoclonal antibody to the CT region of the molecule that recognizes native MUC16 and its enzymatically released CT region. The antibody is useful for immunoprecipitation of the released CT domain as demonstrated with the OVCAR3 ovarian cancer cell line and can be used for detailed cytolocalization in cells as well as in frozen sections of ocular surface and uterine epithelium.

MUC1 induces acquired chemoresistance by upregulating ABCB1 in EGFR-dependent manner

Chemoresistance contributes to cancer relapse and increased mortality in a variety of cancer types, raising a pressing need to better understand the underlying mechanism. MUC1 is abnormally overexpressed in numerous carcinomas and associated with poor prognosis. However, the functional significance of MUC1 in chemoresistance has not been fully elucidated. Here, we showed that MUC1 expression was considerably induced in cells that had acquired chemoresistance at both transcriptional and post-translational levels. Using gain- and loss-of function approaches, we demonstrated a critical role of MUC1 in induction of drug resistance. Through stimulation of EGFR activation and nuclear translocation, MUC1 increased the expression of ATP-binding cassette transporter B1 (ABCB1). Remarkably, targeted suppression of EGFR or ABCB1 by both shRNAs and inhibitors effectively reversed chemoresistance. Moreover, co-administration of the inhibitors of MUC1-EGFR-ABCB1 with paclitaxel significantly blocked not only tumor growth but also relapse in xenograft mouse model. Our data collectively support a model in which MUC1 induces acquired chemotherapy resistance by upregulating ABCB1 in an EGFR-dependent manner, providing a novel molecular basis of using the EGFR inhibitor in MUC1-positive cancers to prevent chemotherapy resistance.

Interaction of galectin-3 with MUC1 on cell surface promotes EGFR dimerization and activation in human epithelial cancer cells

Epidermal growth factor receptor (EGFR) is an important regulator of epithelial cell growth and survival in normal and cancerous tissues and is a principal therapeutic target for cancer treatment. EGFR is associated in epithelial cells with the heavily glycosylated transmembrane mucin protein MUC1, a natural ligand of galectin-3 that is overexpressed in cancer. This study reveals that the expression of cell surface MUC1 is a critical enhancer of EGF-induced EGFR activation in human breast and colon cancer cells. Both the MUC1 extracellular and intracellular domains are involved in EGFR activation but the predominant influence comes from its extracellular domain. Binding of galectin-3 to the MUC1 extracellular domain induces MUC1 cell surface polarization and increases MUC1–EGFR association. This leads to a rapid increase of EGFR homo-/hetero-dimerization and subsequently increased, and also prolonged, EGFR activation and signalling. This effect requires both the galectin-3 C-terminal carbohydrate recognition domain and its N-terminal ligand multi-merization domain. Thus, interaction of galectin-3 with MUC1 on cell surface promotes EGFR dimerization and activation in epithelial cancer cells. As MUC1 and galectin-3 are both commonly overexpressed in most types of epithelial cancers, their interaction and impact on EGFR activation likely makes important contribution to EGFR-associated tumorigenesis and cancer progression and may also influence the effectiveness of EGFR-targeted cancer therapy.

MUC1 facilitates metabolomic reprogramming in triple-negative breast cancer

Background

Mucin1 (MUC1), a glycoprotein associated with chemoresistance and an aggressive cancer phenotype, is aberrantly overexpressed in triple-negative breast cancer (TNBC). Recent studies suggest that MUC1 plays a role in modulating cancer cell metabolism and thereby supports tumor growth. Herein, we examined the role of MUC1 in metabolic reprogramming in TNBC.

Methods

MUC1 was stably overexpressed in MDA-MB-231 TNBC cells and stably knocked down in MDA-MB-468 cells. We performed liquid chromatography-coupled tandem mass spectrometry-assisted metabolomic analyses and physiological assays, which indicated significant alterations in the metabolism of TNBC cells due to MUC1 expression.

Results

Differential analyses identified significant differences in metabolic pathways implicated in cancer cell growth. In particular, MUC1 expression altered glutamine dependency of the cells, which can be attributed in part to the changes in the expression of genes that regulate glutamine metabolism, as observed by real-time PCR analysis. Furthermore, MUC1 expression altered the sensitivity of cells to transaminase inhibitor aminooxyacetate (AOA), potentially by altering glutamine metabolism.

Conclusions

Collectively, these results suggest that MUC1 serves as a metabolic regulator in TNBC, facilitating the metabolic reprogramming of glutamine utilization that influences TNBC tumor growth.

MUC1-C Oncoprotein Integrates a Program of EMT, Epigenetic Reprogramming and Immune Evasion in Human Carcinomas

The MUC1 gene evolved in mammalian species to provide protection of epithelia. The transmembrane MUC1 C-terminal subunit (MUC1-C) signals stress to the interior of the epithelial cell and, when overexpressed as in most carcinomas, functions as an oncoprotein. MUC1-C induces the epithelial-mesenchymal transition (EMT) by activating the inflammatory NF-κB p65 pathway and, in turn, the EMT-transcriptional repressor ZEB1. Emerging evidence has indicated that MUC1-C drives a program integrating the induction of EMT with activation of stem cell traits, epigenetic reprogramming and immune evasion. This mini-review focuses on the potential importance of this MUC1-C program in cancer progression.

Abrogation of MUC5AC Expression Contributes to the Apoptosis and Cell Cycle Arrest of Colon Cancer Cells

Deregulated expressions of mucins have been found in various malignancies and play a pivotal role in carcinogenesis. MUC5AC, as a secreted mucin, is reported to be aberrantly expressed during epithelial cancer progression, including colon cancer. However, the mechanisms of the oncoprotein MUC5AC in the initiation of colon cancer requires further investigation. Here, we collected colon cancer tissues (n = 20) and corresponding paracancerous tissues (n = 20) and found that the expression of MUC5AC was significantly elevated in colon cancer tissues when compared with the corresponding paracancerous tissues. Immunofluorescence indicated that all colon cancer cell lines, including HT29, SW620, and the normal human intestinal epithelial cells FHC, showed the positive expression of MUC5AC, and SW620 exhibited the highest expression. Moreover, knockdown of MUC5AC in SW620 cells remarkably suppressed cell vitality and promoted apoptosis and G1 cell cycle arrest, resulting in the impaired ability of colony formation. Furthermore, the inhibition of MUC5AC in SW620 cells dramatically repressed the cell migration and invasion. These results demonstrated that MUC5AC as an oncogene could be a promising target in the treatment of colon cancer.

Protein serine/threonine phosphatase PPEF-1 suppresses genotoxic stress response via dephosphorylation of PDCD5

Programmed cell death 5 (PDCD5) is believed to play a crucial role in p53 activation; however, the underlying mechanism of how PDCD5 function is regulated during apoptosis remains obscure. Here, we report that the serine/threonine phosphatase PPEF-1 interacts with and dephosphorylates PDCD5 at Ser-119, which leads to PDCD5 destabilization. Overexpression of wild-type PPEF-1, but not inactive PPEF-1^D172N, efficiently suppressed CK2α-mediated stabilization of PDCD5 and p53-mediated apoptosis in response to etoposide (ET). Conversely, PPEF-1 knockdown further enhanced genotoxic stress responses. Notably, PPEF-1 suppressed p53-mediated genotoxic stress response via negative regulation of PDCD5. We also determined that overexpression of wild-type PPEF-1, but not inactive PPEF-1^D172N, significantly increased tumorigenic growth and chemoresistance of A549 human lung carcinoma cells. Collectively, these data demonstrate that PPEF-1 plays a pivotal role in tumorigenesis of lung cancer cells by reducing PDCD5-mediated genotoxic stress responses.

Personalized characterization of diseases using sample-specific networks

A complex disease generally results not from malfunction of individual molecules but from dysfunction of the relevant system or network, which dynamically changes with time and conditions. Thus, estimating a condition-specific network from a single sample is crucial to elucidating the molecular mechanisms of complex diseases at the system level. However, there is currently no effective way to construct such an individual-specific network by expression profiling of a single sample because of the requirement of multiple samples for computing correlations. We developed here with a statistical method, i.e. a sample-specific network (SSN) method, which allows us to construct individual-specific networks based on molecular expressions of a single sample. Using this method, we can characterize various human diseases at a network level. In particular, such SSNs can lead to the identification of individual-specific disease modules as well as driver genes, even without gene sequencing information. Extensive analysis by using the Cancer Genome Atlas data not only demonstrated the effectiveness of the method, but also found new individual-specific driver genes and network patterns for various types of cancer. Biological experiments on drug resistance further validated one important advantage of our method over the traditional methods, i.e. we can even identify such drug resistance genes that actually have no clear differential expression between samples with and without the resistance, due to the additional network information.