Down-regulation of SNAIL suppresses MIN mouse tumorigenesis: Modulation of apoptosis, proliferation, and fractal dimension

Down-regulation of hepatic expression of GHR/STAT5/IGF-1 signaling pathway fosters development and aggressiveness of HCV-related hepatocellular carcinoma: Crosstalk with Snail-1 and type 2 transforming growth factor-beta receptor

Background and aims

So far, few clinical trials are available concerning the role of growth hormone receptor (GHR)/signal transducer and activator of transcription 5 (STAT5)/insulin like growth factor-1 (IGF-1) axis in hepatocarcinogenesis. The aim of this study was to evaluate the hepatic expression of GHR/STAT5/IGF-1 signaling pathway in hepatocellular carcinoma (HCC) patients and to correlate the results with the clinico-pathological features and disease outcome. The interaction between this signaling pathway and some inducers of epithelial-mesenchymal transition (EMT), namely Snail-1 and type 2 transforming growth factor-beta receptor (TGFBR2) was studied too.

Material and methods

A total of 40 patients with HCV-associated HCC were included in this study. They were compared to 40 patients with HCV-related cirrhosis without HCC, and 20 healthy controls. The hepatic expression of GHR, STAT5, IGF-1, Snail-1 and TGFBR2 proteins were assessed by immunohistochemistry.

Results

Compared with cirrhotic patients without HCC and healthy controls, cirrhotic patients with HCC had significantly lower hepatic expression of GHR, STAT5, and IGF-1proteins. They also displayed significantly lower hepatic expression of TGFBR2, but higher expression of Snail-1 versus the non-HCC cirrhotic patients and controls. Serum levels of alpha-fetoprotein (AFP) showed significant negative correlations with hepatic expression of GHR (r = -0.31; p = 0.029) and STAT5 (r = -0.29; p = 0.04). Hepatic expression of Snail-1 also showed negative correlations with GHR, STAT5, and IGF-1 expression (r = -0.55, p = 0.02; r = -0.472, p = 0.035, and r = -0.51, p = 0.009, respectively), whereas, hepatic expression of TGFBR2 was correlated positively with the expression of all these proteins (r = 0.47, p = 0.034; 0.49, p = 0.023, and r = 0.57, p<0.001, respectively). Moreover, we reported that decreased expression of GHR was significantly associated with serum AFP level>100 ng/ml (p = 0.048), increased tumor size (p = 0.02), vascular invasion (p = 0.002), and advanced pathological stage (p = 0.01). Similar significant associations were found between down-regulation of STAT5 expression and AFP level > 100 ng/ml (p = 0.006), vascular invasion (p = 0.009), and advanced tumor stage (p = 0.007). Also, attenuated expression of IGF-1 showed a significant association with vascular invasion (p < 0.001). Intriguingly, we detected that lower expression of GHR, STAT5 and IGF-1 were considered independent predictors for worse outcome in HCC.

Conclusion

Decreased expression of GHR/STAT5/IGF-1 signaling pathway may have a role in development, aggressiveness, and worse outcome of HCV-associated HCC irrespective of the liver functional status. Snail-1 and TGFBR2 as inducers of EMT may be key players. However, large prospective multicenter studies are needed to validate these results.

Niclosamide is a potential therapeutic for familial adenomatosis polyposis by disrupting Axin-GSK3 interaction

The epithelial-mesenchymal transition (EMT) is implicated in tumorigenesis and cancer progression, and canonical Wnt signaling tightly controls Snail, a key transcriptional repressor of EMT. While the suppression of canonical Wnt signaling and EMT comprises an attractive therapeutic strategy, molecular targets for small molecules reverting Wnt and EMT have not been widely studied. Meanwhile, the anti-helminthic niclosamide has been identified as a potent inhibitor of many oncogenic signaling pathways although its molecular targets have not yet been clearly identified. In this study, we show that niclosamide directly targets Axin-GSK3 interaction, at least in part, resulting in suppression of Wnt/Snail-mediated EMT. In vitro and in vivo, disruption of Axin-GSK3 complex by niclosamide induces mesenchymal to epithelial reversion at nM concentrations, accompanied with suppression of the tumorigenic potential of colon cancer. Niclosamide treatment successfully attenuates Snail abundance while increasing E-cadherin abundance in xenograft tumor. Notably, oral administration of niclosamide significantly suppressed adenoma formation in an APC-MIN mice model, indicating that niclosamide is an effective therapeutic for familial adenomatosis polyposis (FAP) patients. In this study, we identified a novel target to control the canonical Wnt pathway and Snail-mediated EMT program, and discovered a repositioned therapeutics for FAP patients.

MicroRNA-30a Regulation of Epithelial-Mesenchymal Transition in Diabetic Cataracts Through Targeting SNAI1

Epithelial-mesenchymal transition (EMT) is a highly conserved and fundamental process in development, fibrosis, and metastasis. During the process, epithelial cells lose their morphology and transcriptional program, and transdifferentiate to mesenchymal cells. It has been reported that lens epithelial cells undergo EMT during cataract formation, and regulation of microRNAs on genes is associated with lens development. However, the molecular mechanisms of this regulation in diabetic cataract still need to be investigated. In the present study, the expression of E-cadherin was downregulated, while the expression of alpha-SMA and vimentin was upregulated in diabetic cataract tissues and the in vitro model, suggesting the involvement of EMT in diabetic cataract formation. Results of miRNA profiling demonstrated that miR-30a was markedly downregulated in diabetic cataract tissues. Overexpression of miR-30a-5p decreased SNAI1, a known modulator of EMT, and the expression of vimentin and alpha-SMA in our diabetic cataract model in vitro. It is concluded that EMT is involved in human diabetic cataract, and upregulation of miR-30a can repress EMT through its targeting of SNAI1 in lens epithelial cells, which make miR-30a a novel target of therapeutic intervention for human diabetic cataract.

Gene regulatory network underlying the immortalization of epithelial cells

BACKGROUND

Tumorigenic transformation of human epithelial cells in vitro has been described experimentally as the potential result of spontaneous immortalization. This process is characterized by a series of cell-state transitions, in which normal epithelial cells acquire first a senescent state which is later surpassed to attain a mesenchymal stem-like phenotype with a potentially tumorigenic behavior. In this paper we aim to provide a system-level mechanistic explanation to the emergence of these cell types, and to the time-ordered transition patterns that are common to neoplasias of epithelial origin. To this end, we first integrate published functional and well-curated molecular data of the components and interactions that have been found to be involved in such cell states and transitions into a network of 41 molecular components. We then reduce this initial network by removing simple mediators (i.e., linear pathways), and formalize the resulting regulatory core into logical rules that govern the dynamics of each of the network components as a function of the states of its regulators.

RESULTS

Computational dynamic analysis shows that our proposed Gene Regulatory Network model recovers exactly three attractors, each of them defined by a specific gene expression profile that corresponds to the epithelial, senescent, and mesenchymal stem-like cellular phenotypes, respectively. We show that although a mesenchymal stem-like state can be attained even under unperturbed physiological conditions, the likelihood of converging to this state is increased when pro-inflammatory conditions are simulated, providing a systems-level mechanistic explanation for the carcinogenic role of chronic inflammatory conditions observed in the clinic. We also found that the regulatory core yields an epigenetic landscape that restricts temporal patterns of progression between the steady states, such that recovered patterns resemble the time-ordered transitions observed during the spontaneous immortalization of epithelial cells, both in vivo and in vitro.

CONCLUSION

Our study strongly suggests that the in vitro tumorigenic transformation of epithelial cells, which strongly correlates with the patterns observed during the pathological progression of epithelial carcinogenesis in vivo, emerges from underlying regulatory networks involved in epithelial trans-differentiation during development.

Association between rectal optical signatures and colonic neoplasia: potential applications for screening

Field carcinogenesis detection represents a promising means for colorectal cancer (CRC) screening, although current techniques (e.g., flexible sigmoidoscopy) lack the requisite sensitivity. The novel optical technology low-coherence enhanced backscattering (LEBS) spectroscopy, allows identification of microscale architectural consequences of the field carcinogenesis in preclinical CRC models with unprecedented accuracy. To investigate the potential clinical translatability of this approach, we obtained biopsies from the normal-appearing rectal mucosa from patients undergoing colonoscopy (n = 219). LEBS signals were recorded through a bench-top instrument. Four parameters characterizing LEBS signal were linearly combined into a single marker. We found that LEBS signal parameters generally mirrored neoplasia progression from patients with no neoplasia, to 5 to 9 mm adenoma and to advanced adenomas. The composite LEBS marker calculated from the LEBS signal paralleled this risk status (ANOVA P < 0.001). Moreover, this was independent of CRC risk factors, benign colonic findings, or clinically unimportant lesions (diminutive adenomas, hyperplastic polyps). For advanced adenomas, the LEBS marker had a sensitivity of 100%, specificity of 80%, and area under the receiver operator characteristic curve of 0.895. Leave-one-out cross-validation and an independent data set (n = 51) supported the robustness of these findings. In conclusion, we provide the first demonstration that LEBS-detectable alterations in the endoscopically normal rectum were associated with the presence of neoplasia located elsewhere in the colon. This study provides the proof of concept that rectal LEBS analysis may potentially provide a minimally intrusive CRC screening technique. Further studies with an endoscopically compatible fiber optic probe are under way for multicenter clinical validation.

Optical markers in duodenal mucosa predict the presence of pancreatic cancer

PURPOSE

Pancreatic cancer remains one of the most deadly cancers and carries a dismal 5-year survival rate of <5%. Therefore, there is urgent need to develop a highly accurate and minimally invasive (e.g., without instrumentation of the pancreatic duct given high rate of complications) method of detection. Our group has developed a collection of novel light-scattering technologies that provide unprecedented quantitative assessment of the nanoscale architecture of the epithelium. We propose a novel approach to predict pancreatic cancer through the assessment of the adjacent periampullary duodenal mucosa without any interrogation of the pancreatic duct or imaging of the pancreas.

EXPERIMENTAL DESIGN

Endoscopically and histologically normal-appearing periampullary duodenal biopsies obtained from 19 pancreatic cancer patients were compared with those obtained at endoscopy from 32 controls. Biopsies were analyzed using our newly developed optical technologies, four-dimensional elastic light-scattering fingerprinting (4D-ELF) and low-coherence enhanced backscattering (LEBS) spectroscopy.

RESULTS

4D-ELF- and LEBS-derived optical markers from normal-appearing periampullary duodenal mucosa can discriminate between pancreatic cancer patients and normal controls with 95% sensitivity and 91% specificity. Moreover, the diagnostic performance of these optical markers was not compromised by confounding factors such as tumor location and stage.

CONCLUSIONS

Here, we showed, for the first time, that optical analysis of histologically normal duodenal mucosa can predict the presence of pancreatic cancer without direct visualization of the pancreas.

Spectral markers in preneoplastic intestinal mucosa: an accurate predictor of tumor risk in the MIN mouse

BACKGROUND

We have reported recently that microarchitectural analysis of the histologically normal mucosa using a novel optics technology, four-dimensional elastic light scattering fingerprinting (ELF), provided unprecedented sensitivity for early detection of colon carcinogenesis. In the present study, we explored the ability of four-dimensional ELF to identify an inherited predisposition to colorectal cancer, an issue of considerable importance for optimizing population screening strategies.

METHODS

We used the MIN mouse, a model whose germ line adenomatous polyposis coli truncation leads to spontaneous intestinal tumorigenesis, thus replicating the human syndrome, familial adenomatous polyposis. Spectral markers were assessed by four-dimensional ELF analysis in MIN mice at preneoplastic time points and compared with age-matched controls (C57BL6 mice with wild-type adenomatous polyposis coli). To assess the responsiveness of spectral markers to chemopreventive agents, a subset of MIN mice was supplemented with celecoxib 1,500 ppm.

RESULTS

Spectral slope, fractal dimension, and principal component 3 were dramatically altered in the uninvolved MIN mouse mucosa at the earliest time points. Furthermore, alteration in spectral variables increased over time, consonant with the microarchitectural underpinnings of subsequent tumorigenesis. Additionally, these markers spatially correlated with future adenoma development (small intestine > colon). Short-term treatment with the potent chemopreventive agent, celecoxib, resulted in near normalization of fractal dimension and principal component 3.

CONCLUSIONS

We report, for the first time, that spectral markers, assayed by four-dimensional ELF, were able to sensitively identify a genetic predisposition for intestinal tumorigenesis before the occurrence of phenotypic manifestations. Moreover, the reversal of spectral markers by celecoxib treatment supports the neoplastic relevance.