Expression of smoothened protein in colon cancer and its prognostic value for postoperative liver metastasis

Epithelial-Mesenchymal Transition in Cancer: A Focus on Itraconazole, a Hedgehog Inhibitor

Cancer, and the resulting mortality from it, is an ever-increasing concern in global health. Cancer mortality stems from the metastatic progression of the disease, by dissemination of the tumor cells. Epithelial-Mesenchymal Transition, the major hypothesis purported to be the origin of metastasis, confers mesenchymal phenotype to epithelial cells in a variety of contexts, physiological and pathological. EMT in cancer leads to rise of cancer-stem-like cells, drug resistance, relapse, and progression of malignancy. Inhibition of EMT could potentially attenuate the mortality. While novel molecules for inhibiting EMT are underway, repurposing drugs is also being considered as a viable strategy. In this review, Itraconazole is focused upon, as a repurposed molecule to mitigate EMT. Itraconazole is known to inhibit Hedgehog signaling, and light is shed upon the existing evidence, as well as the questions remaining to be answered.

Beyond cyclopamine: Targeting Hedgehog signaling for cancer intervention

Hedgehog (Hh) signaling plays a significant role in embryogenesis and several physiological processes, such as wound healing and organ homeostasis. In a pathological setting, it is associated with oncogenesis and is responsible for disease progression and poor clinical outcomes. Hedgehog signaling mediates downstream actions via Glioma Associated Oncogene Homolog (GLI) transcription factors. Inhibiting Hh signaling is an important oncological strategy in which inhibitors of the ligands SMO or GLI have been looked at. This review briefly narrates the Hh ligands, signal transduction, the target genes involved and comprehensively describes the numerous inhibitors that have been evaluated for use in various neoplastic settings.

ATF4 Transcriptionally Activates SHH to Promote Proliferation, Invasion, and Migration of Gastric Cancer Cells

Activating transcription factor 4 (ATF4) is a DNA-binding protein widely generated in mammals, which has two biological characteristics that bind the cAMP response element (CRE). The mechanism of ATF4 as a transcription factor in gastric cancer affecting the Hedgehog pathway remains unclear. Here, we observed that ATF4 was markedly upregulated in gastric cancer (GC) using immunohistochemistry and Western blotting assays in 80 paraffin-embedded GC samples and 4 fresh samples and para-cancerous tissues. ATF4 knockdown using lentiviral vectors strongly inhibited the proliferation and invasion of GC cells. ATF4 upregulation using lentiviral vectors promoted the proliferation and invasion of GC cells. We predicted that the transcription factor ATF4 is bound to the SHH promoter via the JASPA database. Transcription factor ATF4 is bound to the promoter region of SHH to activate the Sonic Hedgehog pathway. Mechanistically, rescue assays showed that ATF4 regulated gastric cancer cells' proliferation and invasive ability through SHH. Similarly, ATF4 enhanced the tumor formation of GC cells in a xenograft model.

Smoothened (SMO) regulates insulin-like growth factor 1 receptor (IGF1R) levels and protein kinase B (AKT) localization and signaling

The oncoprotein Smoothened (SMO), a Frizzled-class-G-protein-coupled receptor, is the central transducer of hedgehog (Hh) signaling. While canonical SMO signaling is best understood in the context of cilia, evidence suggests that SMO has other functions in cancer biology that are unrelated to canonical Hh signaling. Herein, we provided evidence that elevated levels of human SMO show a strong correlation with elevated levels of insulin-like growth factor 1 receptor (IGF1R) and reduced survival in diffuse large B-cell lymphoma (DLBCL). As an integral component of raft microdomains, SMO plays a fundamental role in maintaining the levels of IGF1R in lymphoma and breast cancer cells as well IGF1R-associated activation of protein kinase B (AKT). Silencing of SMO increases lysosomal degradation and favors a localization of IGF1R to late endosomal compartments instead of early endosomal compartments from which much of the receptor would normally recycle. In addition, loss of SMO interferes with the lipid raft localization and retention of the remaining IGF1R and AKT, thereby disrupting the primary signaling context for IGF1R/AKT. This activity of SMO is independent of its canonical signaling and represents a novel and clinically relevant contribution to signaling by the highly oncogenic IGF1R/AKT signaling axis.

Sonic Hedgehog signaling pathway in gynecological and genitourinary cancer (Review)

Cancers of the urinary tract, as well as those of the female and male reproductive systems, account for a large percentage of malignancies worldwide. Mortality is frequently affected by late diagnosis or therapeutic difficulties. The Sonic Hedgehog (SHH) pathway is an evolutionary conserved molecular cascade, which is mainly associated with the development of the central nervous system in fetal life. The present review aimed to provide an in‑depth summary of the SHH signaling pathway, including the characterization of its major components, the mechanism of its upstream regulation and non‑canonical activation, as well as its interactions with other cellular pathways. In addition, the three possible mechanisms of the cellular SHH cascade in cancer tissue are discussed. The aim of the present review was to summarize significant findings with regards to the expression of the SHH pathway components in kidney, bladder, ovarian, cervical and prostate cancer. Reports associated with common deficits and de‑regulations of the SHH pathway were summarized, despite the differences in molecular and histological patterns among these malignancies. However, currently, neither are SHH pathway elements included in panels of prognostic/therapeutic molecular patterns in any of the discussed cancers, nor have the drugs targeting SMO or GLIs been approved for therapy. The findings of the present review may support future studies on the treatment of and/or molecular targets for gynecological and genitourinary cancers.

The Role of Smoothened in Cancer

Smoothened (SMO) belongs to the Hedgehog (HH) signaling pathway, which regulates cell growth, migration, invasion and stem cells in cancer. The HH signaling pathway includes both canonical and noncanonical pathways. The canonical HH pathway functions through major HH molecules such as HH ligands, PTCH, SMO and GLI, whereas the noncanonical HH pathway involves the activation of SMO or GLI through other pathways. The role of SMO has been discussed in different types of cancer, including breast, liver, pancreatic and colon cancers. SMO expression correlates with tumor size, invasiveness, metastasis and recurrence. In addition, SMO inhibitors can suppress cancer formation, reduce the proliferation of cancer cells, trigger apoptosis and suppress cancer stem cell activity. A better understanding of the role of SMO in cancer could contribute to the development of novel therapeutic approaches.

Rotenone restrains colon cancer cell viability, motility and epithelial‑mesenchymal transition and tumorigenesis in nude mice via the PI3K/AKT pathway

Rotenone, a natural hydrophobic pesticide, has been reported to display anticancer activity in a variety of cancer cells. However, the mechanism of rotenone on colon cancer (CC) cell migration, invasion and metastasis is still unknown. In the present study, the cytotoxicity of rotenone on CC cells were detected by the Cell Counting Kit‑8 assay and confirmed by clone formation assay. The effects of rotenone on CC cell invasion and migration activity were determined in vitro by Transwell invasion and wound healing assays, respectively. In addition, to reveal whether rotenone affected the epithelial‑mesenchymal‑transition (EMT) process, reverse transcription‑quantitative PCR, western blotting and immunofluorescence assays were used to detect the expression of EMT markers. The expression levels of the key markers of the PI3K/AKT pathway after rotenone treatment alone or in combination with a PI3K/AKT signaling activator in CC were also detected by western blotting. Finally, the in vivo antitumor effects of rotenone were evaluated in a subcutaneous xenotransplant tumor model treated with an intraperitoneal injection of rotenone. The results of the present study demonstrated that rotenone treatment induced CC cell cytotoxicity and greater effects were observed with increasing concentrations and inhibited cell proliferation compared with untreated cells. In vitro cell function assays revealed that rotenone inhibited CC cell migration, invasion and EMT compared with untreated cells. Mechanically, the phosphorylation levels of AKT and mTOR were downregulated in rotenone‑treated CC cells compared with untreated cells. Additionally, AKT and mTOR phosphorylation levels were increased by the PI3K/AKT signaling activator insulin‑like growth factor 1 (IGF‑1), which was reversed by rotenone treatment. The cell function assays confirmed that the IGF‑1‑activated cell proliferation, migration and invasion were decreased by rotenone treatment. These results indicated that rotenone affected CC cell proliferation and metastatic capabilities by inhibiting the PI3K/AKT/mTOR signaling pathway. In addition, rotenone inhibited tumor growth and metastatic capability of CC, which was confirmed in a xenograft mouse model. In conclusion, the present study revealed that rotenone inhibited CC cell viability, motility, EMT and metastasis in vitro and in vivo by inhibiting the PI3K/AKT/mTOR signaling pathway.

Sonic Hedgehog Signaling in Organogenesis, Tumors, and Tumor Microenvironments

During mammalian embryonic development, primary cilia transduce and regulate several signaling pathways. Among the various pathways, Sonic hedgehog (SHH) is one of the most significant. SHH signaling remains quiescent in adult mammalian tissues. However, in multiple adult tissues, it becomes active during differentiation, proliferation, and maintenance. Moreover, aberrant activation of SHH signaling occurs in cancers of the skin, brain, liver, gallbladder, pancreas, stomach, colon, breast, lung, prostate, and hematological malignancies. Recent studies have shown that the tumor microenvironment or stroma could affect tumor development and metastasis. One hypothesis has been proposed, claiming that the pancreatic epithelia secretes SHH that is essential in establishing and regulating the pancreatic tumor microenvironment in promoting cancer progression. The SHH signaling pathway is also activated in the cancer stem cells (CSC) of several neoplasms. The self-renewal of CSC is regulated by the SHH/Smoothened receptor (SMO)/Glioma-associated oncogene homolog I (GLI) signaling pathway. Combined use of SHH signaling inhibitors and chemotherapy/radiation therapy/immunotherapy is therefore key in targeting CSCs.

Circular RNA SMO sponges miR-338-3p to promote the growth of glioma by enhancing the expression of SMO

Glioma is one of the most common tumors in the brain and complete cure still a challenge. The present research aimed to investigate the molecular mechanism of circular RNA SMO (circSMO742) in glioma, via targeting miR-338-3p and regulating SMO expression. QRT-PCR was utilized to examine the expression profiles of circSMO742 and microRNA-338-3p (miR-338-3p) in glioma. SMO protein in glioma was tested via western blot. RNA pulldown assay and dual luciferase reporter assays were used to explore the targeting correlation between RNAs. MTT assay, transwell assays and flow cytometry were used to investigate cell proliferation, migration and invasion, and apoptosis, respectively. Tumor xenograft was done to ascertain the effect of circSMO742 knocking down on tumor growth. CircSMO742 and SMO were highly expressed in glioma tissues, while miR-338-3p expression was reduced. CircSMO742 together with SMO could promote cells proliferation, migration and invasion while inhibit cells apoptosis, whereas miR-338-3p showed negative impacts on the cell activity. Knocking down of circSMO742 suppressed glioma growing in vivo. CircSMO742 promoted glioma growth by sponging miR-338-3p to regulate SMO expression. Our research revealed a new molecular mechanism of glioma growth and provide a fresh perspective on circRNAs in glioma progression.

Expression of the Sonic Hedgehog pathway components in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common and the most aggressive histopathological subtype of kidney cancer, with patients exhibiting high mortality rates for metastatic tumors. The Sonic Hedgehog (SHH) pathway serves a crucial role in embryonic development. The abnormal activity of SHH signaling is observed in a broad range of malignancies. However, its role in ccRCC is still undetermined. The aim of the present study was to assess the expression of the SHH pathway genes in ccRCC. Neoplastic and morphologically unchanged kidney tissues were obtained during radical nephrectomy from 37 patients with ccRCC. The SHH, PTCH1, SMO and GLI1 mRNA levels were assessed using the reverse transcription-quantitative PCR. Western blot analysis was used to assess the full-length and C-terminal SHH protein level. The mRNA levels of SHH, SMO and GLI1 were approximately 2-, 2,5- and 7-fold higher in ccRCC tissue compared with control kidney tissue, respectively. Correlational analysis between the mRNA levels of SHH pathway genes and patients' clinicopathological factors revealed decreased and increased mRNA levels of PTCH1 and SMO respectively, in tumor samples derived from older patients (age >62). Furthermore, the level of C-terminal SHH protein in ccRCC samples was significantly lower in a group of males compared with females. No correlation was exhibited between molecular data and patient survival. Western blot analysis indicated a ~3-fold higher level of SHH full-length protein, and a 4-fold lower level of the C-terminal SHH protein domain, in ccRCC tumor tissues compared with normal kidney samples. The current study indicated an involvement of the SHH pathway in ccRCC development.

Nuclear localization and Overexpression of Smoothened in Pancreatic and Colorectal Cancers

Smoothened (SMO) is a significant signalling protein which functions as a key transducer for the hedgehog signalling pathway, an important signalling mechanism with key roles in development and oncogenesis. The correlation of expression dynamics of SMO with pancreatic and colorectal cancer genesis has been known but with ambiguity. Therefore, in this study, we investigated messenger RNA (mRNA) and protein expression of SMO in pancreatic and colorectal cancers in our population and assessed relationship with various clinicopathological parameters. Surgically resected tumour and adjacent histologically normal tissues from 33 and 61 pancreatic and colorectal cancer patients were investigated in the present study. Expression of SMO was analysed by quantitative real-time polymerase chain reaction and immunohistochemistry. At mRNA level, SMO was overexpressed in 72.72% (24 of 33) and 50.81% (31 of 61) of the pancreatic and colorectal cancer cases as compared with their adjacent normal tissues. SMO immunohistochemical analysis revealed nuclear localization and overexpression was observed in 51.51% (17 of 33) and 40.98% (25 of 61) of pancreatic and colorectal cancer tissues. SMO overexpression was significantly associated with smoking, late-stage disease and lymph node metastasis in patients with Colorectal cancer. Our results showed that SMO is dysregulated in pancreatic and colorectal cancers and may be considered as a target in cancer therapeutics.

SERPINA3 Silencing Inhibits the Migration, Invasion, and Liver Metastasis of Colon Cancer Cells

OBJECTIVE

To investigate the impact of SERPINA3 on the migration, invasion, and liver metastasis of colon cancer cells.

METHODS

Immunohistochemical staining was conducted to determine SERPINA3 expression in the cancer and adjacent normal tissues of 131 patients suffering from colon cancer. In vitro experiment, colon cancer cells with low (HT-29P), intermediate (KM-12C), and high (HT-29LMM, KM-12L4) metastatic potential were obtained to examine SERPINA3 expression levels. Besides, quantitative real-time PCR (qRT-PCR) and Western Blot were performed to detect SERPINA3 expression in HT-29LMM and KM-12L4 cells transfected with SERPINA3 siRNA; Wound-healing and Transwell assays to measure cell migration and invasion, respectively; and ELISA to detect MMP-2 and MMP-9 levels. In vivo experiment, mice with liver metastasis of colon cancer were established to observe the effect of SERPINA3 silencing on liver metastasis. Immunohistochemical assay was applied to evaluate the expressions of Serpina3, Mmp-2, Mmp-9, and proliferating cell nuclear antigen (Pcna) in liver metastasis tissues.

RESULTS

SERPINA3 in colon cancer tissues was higher than in adjacent normal tissues, which was associated with patients' clinicopathological features. Besides, SERPINA3 expression showed a rising trend in low, intermediate, and high metastatic potential colon cancer cells. After KM-12L4 and HT-29LMM cells transfected with SERPINA3 siRNA, the migration and invasive ability of cells, as well as the expression levels of MMP-2 and MMP-9 were all decreased. Moreover, SERPINA3 siRNA could not only reduce live metastasis of mice, but also down-regulate the expression of Mmp-2 and Mmp-9 in liver metastasis tissues.

CONCLUSION

SERPINA3 silencing could inhibit the migration, invasion, and liver metastasis of colon cancer cells.

Hedgehog signaling pathway in colorectal cancer: function, mechanism, and therapy

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers worldwide. It is a complicated and often fatal cancer, and is related to a high disease-related mortality. Around 90% of mortalities are caused by the metastasis of CRC. Current treatment statistics shows a less than 5% 5-year survival for patients with metastatic disease. The development and metastasis of CRC involve multiple factors and mechanisms. The Hedgehog (Hh) signaling plays an important role in embryogenesis and somatic development. Abnormal activation of the Hh pathway has been proven to be related to several types of human cancers. The role of Hh signaling in CRC, however, remains controversial. In this review, we will go through previous literature on the Hh signaling and its functions in the formation, proliferation, and metastasis of CRC. We will also discuss the potential of targeting Hh signaling pathway in the treatment, prognosis, and prevention of CRC.

The Prognostic Significance of the Hedgehog Signaling Pathway in Colorectal Cancer

Despite significant advances in the management of colorectal cancer (CRC) the identification of new prognostic biomarkers continues to be a challenge. Since its initial discovery, the role of the Hedgehog (Hh) signaling pathway in carcinogenesis has been extensively studied. We herein review and comment on the prognostic significance of the Hh signaling pathway in CRC. The differential expression of Hh pathway components between malignant and nonmalignant conditions as well as correlation of Hh activation markers with various clinicopathological parameters and the effect on disease-free survival, overall survival, and disease recurrence in patients with CRC is summarized and discussed. According to the studies reviewed herein the activation of the Hh pathway seems to be correlated with adverse clinicopathological features and worse survival. However, to date study results show significant variability with regard to the effect on outcomes. Such results need to be interpreted carefully and emphasize the need for further well designed studies to characterize the actual influence of the Hh pathway in CRC prognosis.

Down-regulated MYH11 expression correlates with poor prognosis in stage II and III colorectal cancer

The MYH11 gene may be related to cell migration and adhesion, intracellular transport, and signal transduction. However, its relationship with prognosis is still uncertain. The aim of this study was to investigate correlations between MYH11 gene expression and prognosis in 58 patients with stage II and III colorectal cancer. Quantitative real-time polymerase chain reaction was performed in fresh CRC tissues to examine mRNA expression, and immunohistochemistry was performed with paraffin-embedded specimens for protein expression. On univariate analysis, MYH11 expression at both mRNA and protein levels, perineural invasion and lymphovascular invasion were related to disease-free survival (p<0.05; log-rank test). Cancers with lower MYH11 expression were more likely to have a poor prognosis. Otherwise, MYH11 expression was unrelated to patient clinicopathological features. On multivariate analysis, low MYH11 expression proved to be an independent adverse prognosticator (p<0.05). These findings show that MYH11 can contribute to predicting prognosis in stage II and III colorectal cancers.

SMO expression in colorectal cancer: associations with clinical, pathological, and molecular features

BACKGROUND

Smoothened, frizzled family receptor (SMO) is an important component of the hedgehog signaling pathway, which has been implicated in various human carcinomas. However, clinical, molecular, and prognostic associations of SMO expression in colorectal cancer remain unclear.

METHODS

Using a database of 735 colon and rectal cancers in the Nurse's Health Study and the Health Professionals Follow-up Study, we examined the relationship of tumor SMO expression (assessed by immunohistochemistry) to prognosis, and to clinical, pathological, and tumor molecular features, including mutations of KRAS, BRAF, and PIK3CA, microsatellite instability, CpG island methylator phenotype (CIMP), LINE-1 methylation, and expression of phosphorylated AKT and CTNNB1.

RESULTS

SMO expression was detected in 370 tumors (50 %). In multivariate logistic regression analysis, SMO expression was independently inversely associated with phosphorylated AKT expression [odds ratio (OR) 0.48; 95 % confidence interval (CI) 0.34-0.67] and CTNNB1 nuclear localization (OR 0.48; 95 % CI 0.35-0.67). SMO expression was not significantly associated with colorectal cancer-specific or overall survival. However, in CIMP-high tumors, but not CIMP-low/0 tumors, SMO expression was significantly associated with better colorectal cancer-specific survival (log-rank P = 0.012; multivariate hazard ratio, 0.36; 95 % CI 0.13-0.95; P interaction = 0.035, for SMO and CIMP status).

CONCLUSIONS

Our data reveal novel potential associations between the hedgehog, the WNT/CTNNB1, and the PI3K (phosphatidylinositol-4,5-bisphosphonate 3-kinase)/AKT pathways, supporting pivotal roles of SMO and hedgehog signaling in pathway networking. SMO expression in colorectal cancer may interact with tumor CIMP status to affect patient prognosis, although confirmation by future studies is needed.

Hedgehog related protein expression in breast cancer: gli-2 is associated with poor overall survival

Background

The hedgehog (Hh) signaling pathway is known to play a critical role in various malignancies, but its clinicopathologic role in breast cancer is yet to be established.

Methods

Tissue microarray blocks from 334 cases of breast cancer were prepared. The expression of six Hh signaling proteins including sonic hedgehog (Shh), patched (Ptch), smoothened (Smo), and the glioma-associated oncogene (Gli)-1, Gli-2, and Gli-3 were analyzed immunohistochemically.

Results

The expression of Hh signaling proteins was significantly correlated with some prognostic factors including the correlation of lymph node metastasis with the expression of Shh (p=0.001) and Ptch (p=0.064), the correlation of the stages with Shh and Gli-3 expression (p=0.007 and p=0.024, respectively), the correlation of the nuclear grade with the Smo (p=0.004) and Gli-3 (p=0.000), and the correlation of the histologic grade with the Ptch (p=0.016), Smo (p=0.007), and Gli-3 (p=0.000). The Shh, Ptch, Smo, Gli-1, and Gli-2 expression was significantly different between the phenotypes (p=0.000, p=0.001, p=0.004, p=0.039, and p=0.031, respectively). Gli-2 expression was correlated with a worse overall survival outcome (p=0.012).

Conclusions

Hh pathway activation is correlated with a more aggressive clinical behavior in breast carcinomas. The comparison of phenotypes suggested that the Hh pathway may be a useful therapeutic target for breast carcinoma. Patients with Gli-2 expression had a significantly lower overall survival rate and, therefore, it showed promise as a prognostic marker.