Blocking Notch1 signaling by RNA interference can induce growth inhibition in HeLa cells

Human papillomavirus infection and autoimmune disorders: a tertiary center experience

This study aimed to investigate the relationship between HPV and autoimmune disorders. We retrospectively evaluated 62 women who had HPV-DNA positivity in terms of autoimmune disorders (autoimmune antibody positivity, chronic inflammatory diseases and autoimmune diseases). The patients were divided into two groups according to autoimmune disorder positivity (autoimmune positive (n = 30), autoimmune negative (n = 32)) and compared with each other in terms of single and multiple HPV-DNA types, high and low-risk HPV-DNA types, and Pap smear findings. We determined that 48.4% of the HPV-DNA positive patients had autoimmune disorders. We found that 15 of 62 (24.2%) women had more than one type of HPV and HPV type 16 was the dominant type in this study (58.2%). A total of 27.4% of HPV-DNA positive patients had abnormal cytological findings. There was no statistically significant difference between autoimmune groups in terms of the presence of high-risk HPV types, multiple HPV types and abnormal cytological findings (P = 0.531, P = 0.558 and P = 0.234, respectively). The prevalence of autoimmune disorders was high among HPV-DNA positive women. On the other hand, the rate of high-risk HPV type positivity, multiple HPV infections and cytopathological findings were similar between the autoimmune positive and negative groups.

Loss of nuclear NOTCH1, but not its negative regulator NUMB, is an independent predictor of cervical malignancy

The participation of NOTCH signaling in invasive cervical cancer (ICC) remains controversial since both tumor suppressive and oncogenic properties have been described. Additionally, the role of NUMB, a negative regulator of NOTCH, remains unclear in ICC. We aimed to investigate the role of NOTCH1 and NUMB expression and their localization in cervical intraepithelial neoplasia (CIN) and ICC samples. A total of 144 biopsies were obtained from the Instituto Nacional de Cancerología, México from 2004 to 2017, and were subjected to immunohistochemistry for NOTCH1 and NUMB. We found that nuclear NOTCH1 expression was more frequently found in CIN samples compared with ICC (77.55% vs. 15.79%, p = 0.001). NUMB was almost exclusively found in the nucleus of CIN samples (32.65% vs. 6.32%, p = 0.001). Cytoplasmic expression of NOTCH1 (44.21%) and NUMB (35.79%) was the most frequent localization in ICC. Multivariable-adjusted analysis showed that the loss of nuclear NOTCH1 expression was an independent predictor of malignancy (β = -3.428, 95% confidence interval [95% CI] = -5.127, -1.728, p = 0.001). In contrast, the association between cytoplasmic NUMB expression and cervical cancer was lost after adjusting for nuclear NOTCH1 expression (β = 2.074, 95% [CI] = -0.358, 4.506, P = 0.094). Additionally, patients with cytoplasmic NOTCH1 expression showed a borderline association with longer overall survival (OS) than those with nuclear NOTCH1 expression (P = 0.08). Our data suggest that the loss of nuclear NOTCH1 but not NUMB might be an independent predictor of malignancy in cervical cancer.

Notch Signaling Activation in Cervical Cancer Cells Induces Cell Growth Arrest with the Involvement of the Nuclear Receptor NR4A2

Cervical cancer is a second leading cancer death in women world-wide, with most cases in less developed countries. Notch signaling is highly conserved with its involvement in many cancers. In the present study, we established stable cervical cell lines with Notch activation and inactivation and found that Notch activation played a suppressive role in cervical cancer cells. Meanwhile, the transient overexpression of the active intracellular domain of all four Notch receptors (ICN1, 2, 3, and 4) also induced the suppression of cervical cancer Hela cell growth. ICN1 also induced cell cycle arrest at phase G1. Notch1 signaling activation affected the expression of serial genes, especially the genes associated with cAMP signaling, with an increase of genes like THBS1, VCL, p63, c-Myc and SCG2, a decrease of genes like NR4A2, PCK2 and BCL-2. Particularly,

The nuclear receptor NR4A2 was observed to induce cell proliferation via MTT assay and reduce cell apoptosis via FACS assay. Furthermore, NR4A2's activation could reverse ICN1-induced suppression of cell growth while erasing ICN1-induced increase of tumor suppressor p63. These findings support that Notch signaling mediates cervical cancer cell growth suppression with the involvement of nuclear receptor NR4A2. Notably, Notch/NR4A2/p63 signaling cascade possibly is a new signling pathway undisclosed.

Simvastatin induces growth inhibition and apoptosis in HepG2 and Huh7 hepatocellular carcinoma cells via upregulation of Notch1 expression

Statins, cholesterol‑lowering drugs, are one of the most commonly prescribed types of medications. Previous studies have suggested that simvastatin may inhibit the cell function and tumor growth of hepatocellular carcinoma (HCC) cells; however, the molecular mechanisms underlying simvastatin‑induced apoptosis in HCC cells remains to be elucidated. The aim of the present study was to investigate the role of simvastatin in the regulation of cell viability, proliferation and apoptosis in HepG2 and Huh7 HCC cells, and to elucidate the specific regulatory mechanisms by which simvastatin proceeds. MTT, trypan blue and flow cytometric analyses were performed in order to detect viability, proliferation and apoptosis in HepG2 and Huh7 cells. The results of the present study demonstrated that simvastatin significantly decreased cell viability and proliferation as well as increased apoptosis in HepG2 and Huh7 cells compared to that in untreated cells. In addition, reverse transcription quantitative polymerase chain reaction and western blot analysis revealed that simvastatin‑treated cells exhibited increased expression levles of Notch1, p53, and Bax, as well as decreased expression levels of B cell lymphoma 2; furthermore, Notch1 upregulation resulted in the inhibition of Akt phosphorylation. In conclusion, the results of the present study indicated that simvastatin significantly promoted apoptosis in HCC cells, the mechanism of which may have proceeded via the upregualtion of the Notch1 gene in the Akt‑dependent signaling pathway.

Notch1 controls cell invasion and metastasis in small cell lung carcinoma cell lines

INTRODUCTION

Notch signaling plays a key role in a wide variety of human neoplasms, and it can be either oncogenic or anti-proliferative. Moreover, Notch function in regulating cancer is unpredictable, and its outcome is strictly context-dependent.

AIM

To study the role of Notch1 signaling in human small cell lung carcinoma (SCLC) and its effect on cell invasion and metastasis.

MATERIALS AND METHODS

We used small interfering RNA (siRNA) technology, to down-regulate the expression of Notch1 in H69AR and SBC3 SCLC cells. On the other hand, we up-regulated Notch1 in H69 and H1688 SCLC cells through transfection with venus Notch1 intracellular domain (v.NICD) plasmid. In addition, H69 cells with v.NICD were xenotransplanted into immune-compromised Rag2(-/-) Jak3(-/-) mice, for analysis of ex vivo tumor epithelial mesenchymal transition (EMT) phenotype and for detection of metastatic cancer cells in the lung tissues. Moreover, we examined the metastatic ability for H69AR and SBC3 cells transfected with siRNA against Notch1, compared to their subsequent controls, by use of tail vein xenograft mouse models.

RESULTS

Notch1 controls cell adhesion and EMT. Overexpression of Notch1 in SCLC switched off EMT, cell motility and cell metastatic potential.

CONCLUSION

Our results demonstrate that activation of Notch1 signaling pathway may represent a new strategy for treating human SCLC.

A novel anticancer therapy that simultaneously targets aberrant p53 and Notch activities in tumors

Notch signaling pathway plays an important role in tumorigenesis by maintaining the activity of self-renewal of cancer stem cells, and therefore, it is hypothesized that interference of Notch signaling may inhibit tumor formation and progression. H101 is a recombinant oncolytic adenovirus that is cytolytic in cells lacking intact p53, but it is unable to eradicate caner stem cells. In this study, we tested a new strategy of tumor gene therapy by combining a Notch1-siRNA with H101 oncolytic adenovirus. In HeLa-S3 tumor cells, the combined therapy blocked the Notch pathway and induced apoptosis in tumors that are p53-inactive. In nude mice bearing xenograft tumors derived from HeLa-S3 cells, the combination of H101/Notch1-siRNA therapies inhibited tumor growth. Moreover, Notch1-siRNA increased Hexon gene expression at both the transcriptional and the translational levels, and promoted H101 replication in tumors, thereby enhancing the oncolytic activity of H101. These data demonstrate the feasibility to combine H101 p53-targted oncolysis and anti-Notch siRNA activities as a novel anti-cancer therapy.

Therapeutic efficacy by targeting correction of Notch1-induced aberrants in uveal tumors

There is a need for more effective treatments for uveal melanoma. The recombinant oncolytic adenovirus H101 replicates specifically in p53-depleted tumor cells, and has been approved for use by the Chinese State Food and Drug Administration. However, this treatment is associated with subsequent remission. Transfection of uveal melanoma cells with a small interfering RNA against Notch1 (siNotch1) effectively suppressed Notch1 expression, resulting in significant cell growth inhibition when combined with H101 treatment. Combined treatment with siNotch1 and H101 (H101-Notch1-siRNA) greatly enhanced apoptosis and cell cycle arrest in vitro as compared to treatment with H101 or siNotch1 alone. For in vivo treatments, the combined treatment of siNotch1 and H101 showed remarkable tumor growth inhibition and prolonged mouse survival in the OCM1 xenograft model. We predict that Notch pathway deregulation could be a feature of uveal melanoma, and could be a therapeutic target, especially if p53 is concurrently targeted.

Notch1-mediated tumor suppression in cervical cancer with the involvement of SST signaling and its application in enhanced SSTR-targeted therapeutics

The role of Notch signaling in cervical cancer is seemingly controversial. To confirm the function of Notch signaling in this type of cancer, we established a stable Notch1-activated cervical cancer HeLa cell line. We found that Notch1 activation resulted in apoptosis, cell cycle arrest, and tumor suppression. At the molecular level, we found that a variety of genes associated with cyclic AMP, G protein-coupled receptor, and cancer signaling pathways contributed to Notch1-mediated tumor suppression. We observed that the expression of somatostatin (SST) was dramatically induced by Notch1 signaling activation, which was accompanied by enhanced expression of the cognate SST receptor subtype 1 (SSTR1) and SSTR2. Certain genes, such as tumor protein 63 (TP63, p63), were upregulated, whereas others, such as B-cell lymphoma 2 (BCL-2), Myc, Akt, and STAT3, were downregulated. Subsequently, knockdown of Notch1-induced SST reversed Notch1-induced decrease of BCL-2 and increase of p63, indicating that Notch1-induced tumor suppression may be partly through upregulating SST signaling. Our findings support a possible crosstalk between Notch signaling and SST signaling. Moreover, Notch-induced SSTR activation could enhance SSTR-targeted cancer chemotherapy. Valproic acid (VPA), a histone deacetylase inhibitor, suppressed cell growth and upregulated the expression of Notch1 and SSTR2. A combination therapy with VPA and the SSTR2-targeting cytotoxic conjugate CPT-SST strongly led to greater suppression, as compared to each alone. Our findings thus provide us with a promising clinical opportunity for enhanced cancer therapy using combinations of Notch1-activating agents and SSTR2-targeting agents.

Enhanced therapeutic efficacy by simultaneously targeting two genetic defects in tumors

Targeting tumor-specific gene abnormalities has become an attractive approach in developing therapeutics to treat cancer. Overexpression of Bcl2 and mutations of p53 represent two of the most common molecular defects in tumors. In the nucleus, p53 induces cell cycle arrest, while it interacts with Bcl2 outside of the nucleus to regulate signal pathways involved in apoptosis. To potentiate antitumor activity, we tested a "double target" approach to antitumor therapy by combining H101, a recombinant oncolytic adenovirus that targets the inactive p53 in tumors, with a small interfering RNA (siBCL2) that targets Bcl2. In cell culture, the combined treatment significantly enhanced apoptosis and cytotoxicity as compared with treatment with either H101 or siBCL2 alone. In animals carrying tumor xenographs, combined H101 and siBCL2 treatment significantly inhibited tumor growth and prolonged survival. At the end of the study, all animals in the combined therapy group survived and two of the five animals showed complete eradication of their tumors. Interestingly, siBCL2 treatment increased H101 viral replication in both treated cells and tumor tissues. Simultaneously targeting two tumor-specific gene abnormalities using an oncolytic adenovirus and siRNA potentiates total antitumor activity.