Targeting the hedgehog signaling pathway with interacting peptides to Patched-1

Patched 1-interacting Peptide Represses Fibrosis in Pancreatic Cancer to Augment the Effectiveness of Immunotherapy

Pancreatic ductal adenocarcinoma (PDAC) is resistant to immunotherapy. As a factor of resistance, the dense fibrosis of this cancer acts as a barrier to inhibit immune cell infiltration into a tumor. We examined the influence of a Hedgehog signal inhibitor, Patched 1-interacting peptide, on fibrosis, infiltration of immune cells, and immunotherapeutic effects on PDAC. We found that this peptide inhibited proliferation and migration of cancer-associated fibroblasts and cancer cells. Furthermore, this peptide reduced the production of extracellular matrix and transforming growth factor β1 in cancer-associated fibroblasts and induced expression of HLA-ABC in PDAC cells and interferon-γ in lymphocytes. In vivo, the peptide suppressed fibrosis of PDAC and increased immune cell infiltration into tumors. The combination of this peptide and an anti-programmed death-1 antibody augmented the antitumor effect, and this combination showed the same effect in experiments using cancer cells and autologous lymphocytes. These results indicate that, in addition to the direct effect of tumor suppression, the Patched 1-interacting peptide increases the infiltration of immune cells by reducing fibrosis of PDAC and consequently enhances the effect of immunotherapy. Therefore, treatment with this peptide may be a novel therapy with 2 different mechanisms: direct tumor suppression and enhancing the immune response against PDAC.

MeCP2 Regulates PTCH1 Expression Through DNA Methylation in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease, in which pathogenesis is not clear. Many research demonstrated that fibroblast-like synoviocytes (FLSs) play a key role in RA pathogenesis, join in the cartilage injury and hyperplasia of the synovium, and contribute to the release of inflammatory cytokines. We used adjuvant arthritis (AA) rats as RA animal models. The methyl-CpG-binding protein 2 (MeCP2) enables the suppressed chromatin structure to be selectively detected in AA FLSs. Overexpression of this protein leads to an increase of integral methylation levels. Some research has confirmed the hedgehog (Hh) signaling pathway plays an important role in RA pathogenesis; furthermore, patched 1 (PTCH1) is a negative fraction of Hh signaling pathway. We used 5-aza-2'-deoxycytidine (5-azadc) as DNA methylation inhibitor. In our research, we found MeCP2 reduced PTCH1 expression in AA FLSs; 5-azadc obstructed the loss of PTCH1 expression. 5-Azadc, treatment of AA FLSs, also blocks the release of inflammatory cytokines. In order to probe the potential molecular mechanism, we assumed the epigenetic participation in the regulation of PTCH1. Results demonstrated that PTCH1 hypermethylation is related to the persistent FLS activation and inflammation in AA rats. Knockdown of MeCP2 using small-interfering RNA technique added PTCH1 expression in AA FLSs. Our results indicate that DNA methylation may offer molecule mechanisms, and the reduced PTCH1 methylation level could regulate inflammation through knockdown of MeCP2. Graphical Abstract PTCH1 is an inhibitory protein of the Hedgehog signaling pathway. Increased expression of PTCH1 can inhibit the expression of Gli1 and Shh, thereby inhibiting the activation of Hedgehog signaling pathway. Inactivated Hedgehog signaling pathway inhibits the secretion of IL-6 and TNF-α. MeCP2 mediates hypermethylation of PTCH1 gene and decreases the expression of PTCH1 protein, thus activating Hedgehog signaling pathway and increasing secretion of IL-6 and TNF-α.

Molecular Targets of Active Anticancer Compounds Derived from Marine Sources

Over the past decades, a number of novel compounds, which are produced in the marine environment, have been found to exhibit the anticancer effects. This review focuses on molecular targets of marine-derived anticancer candidates in clinical and preclinical studies. They are kinases, transcription factors, histone deacetylase, the ubiquitin-proteasome system, and so on. Specific emphasis of this review paper is to provide information on the optimization of new target compounds for future research and development of anticancer drugs, based on the identification of structures of these target molecules and parallel compounds.

Natural paniceins from mediterranean sponge inhibit the multidrug resistance activity of Patched and increase chemotherapy efficiency on melanoma cells

Multidrug resistance has appeared to mitigate the efficiency of anticancer drugs and the possibility of successful cancer chemotherapy. The Hedgehog receptor Patched is a multidrug transporter expressed in several cancers and as such it represents a new target to circumvent chemotherapy resistance. We report herein that paniceins and especially panicein A hydroquinone, natural meroterpenoids produced by the Mediterranean sponge Haliclona (Soestella) mucosa, inhibit the doxorubicin efflux activity of Patched and enhance the cytotoxicity of this chemotherapeutic agent on melanoma cells in vitro. These results are supported by the molecular docking performed on the structure of the bacterial drug efflux pump AcrB and on the Patched model built from AcrB structure. Docking calculations show that panicein A hydroquinone interacts with AcrB and Patched model close to the doxorubicin binding site. This compound thus appears as the first antagonist of the doxorubicin efflux activity of Patched. The use of inhibitors of Patched drug efflux activity in combination with classical chemotherapy could represent a novel approach to reduce tumor drug resistance, recurrence and metastasis.

Anthothecol-encapsulated PLGA nanoparticles inhibit pancreatic cancer stem cell growth by modulating sonic hedgehog pathway

Anthothecol, a limonoid isolated from plant Khaya anthotheca (Meliaceae), is an antimalarial compound. The objectives of this study were to examine the molecular mechanisms by which anthothecol-encapsulated PLGA-nanoparticles (Antho-NPs) regulate the behavior of pancreatic cancer stem cells (CSCs). Antho-NPs inhibited cell proliferation and colony formation, and induced apoptosis in pancreatic CSCs and cancer cell lines, but had no effects on human normal pancreatic ductal epithelial cells. Antho-NPs inhibited self-renewal capacity of pancreatic CSCs isolated from human and Kras(G12D) mice. Furthermore, antho-NPs suppressed cell motility, migration and invasion by up-regulating E-cadherin and inhibiting N-cadherin and Zeb1. In addition, Antho-NPs inhibited pluripotency maintaining factors and stem cell markers, suggesting their inhibitory role on CSC population. Anthothecol disrupted binding of Gli to DNA, and inhibited Gli transcription and Gli target genes. Our studies establish preclinical significance of Antho-NPs for the treatment and/or prevention of pancreatic cancer.

FROM THE CLINICAL EDITOR

Despite medical advances, the prognosis of pancreatic cancer remains poor. The search for an effective treatment has been under intensive research for some time. In this article, the authors investigated the efficacy and mechanism of anthothecol (an antimalarial compound), encapsulated by PLGA nanoparticles (Antho-NPs), against pancreatic cancer cell lines. It was found that Antho-NPs acted via the Sonic hedgehog signaling pathway and inhibited cancer stem cell growth. These results have provided important basis for further clinical trials.

Functional significance of expression of Hedgehog pathway components Shh, Ptch1, Smo and Gli1 in human pancreatic cancer

AIM: To detect the expression of Hedgehog pathway components Sonic Hedgehog (Shh), Patched1 (Ptch1), Smoothened (Smo) and glioma-associated oncogene homolog 1 (Gli1) genes in pancreatic cancer, and to discuss their biological significance.

METHODS: Expression of Shh, Ptch1, Smo and Gli1 mRNAs was evaluated by RT-PCR in 48 cases of pancreatic cancer and matched tumor adjacent tissue.

RESULTS: The relative expression levels of Shh, Ptch1, Smo and Gli1 mRNAs in pancreatic cancer were 0.652 ± 0.036, 0.604 ± 0.063, 0.493 ± 0.011 and 0.512 ± 0.052, respectively, significantly higher than those in tumor adjacent tissue (0.312 ± 0.013, 0.319 ± 0.053, 0.214 ± 0.046 and 0.247 ± 0.059) (P < 0.05). Overexpression of these genes was associated with tumor differentiation (P < 0.05), but not with age, gender, tumorous size, TNM stage, lymph node metastasis, or CA19-9 (P > 0.05).

CONCLUSION: The expression of Shh, Ptch1, Smo and Gli1 is increased in human pancreatic cancer. The genesis and development of pancreatic cancer may be associated with the abnormal activation of Hedgehog signaling pathway.

Patched targeting peptides for imaging and treatment of hedgehog positive breast tumors

High tumor hedgehog expression is correlated with poor prognosis in invasive ductal carcinoma. Peptides which bind the patched receptor have recently been reported to have a growth inhibitory effect in tumors with activated hedgehog signaling. We sought to examine growth inhibition with these peptides in breast cancer cells and use these peptides as molecular imaging probes to follow changes in hedgehog expression after chemotherapy. Significant growth inhibition was observed in breast cancer cell lines treated with PTCH-blocking peptides. Significant in vitro uptake was observed with both FITC- and ^99mTc-EC-peptide conjugates. In vivo imaging studies displayed greater accumulation of ^99mTc-labeled peptides within tumors as compared to adjacent muscle tissue. Patched receptor expression increased after treatment and this correlated with an increase in tumor radiotracer uptake. These studies suggest that peptides which bind the sonic hedgehog docking site in patched receptor correlate with patched expression and can be used to image patched in vivo. Further, our data suggest that radiolabeled peptides may enable us to examine the activity of the hedgehog signaling pathway and to evaluate response to anti-cancer therapies.

Inhibition of Hedgehog signalling by NVP-LDE225 (Erismodegib) interferes with growth and invasion of human renal cell carcinoma cells

Background:

Multiple lines of evidence support that the Hedgehog (Hh) signalling has a role in the maintenance and progression of different human cancers. Therefore, inhibition of the Hh pathway represents a valid anticancer therapeutic approach for renal cell carcinoma (RCC) patients. NVP-LDE225 is a Smoothened (Smo) antagonist that induces dose-related inhibition of Hh and Smo-dependent tumour growth.

Methods:

We assayed the effects of NVP-LDE225 alone or in combination with everolimus or sunitinib on the growth and invasion of human RCC models both in vitro and in vivo. To this aim, we used a panel of human RCC models, comprising cells with acquired resistance to sunitinib – a multiple tyrosine kinase inhibitor approved as a first-line treatment for RCC.

Results:

NVP-LDE225 cooperated with either everolimus or sunitinib to inhibit proliferation, migration, and invasion of RCC cells even in sunitinib-resistant (SuR) cells. Some major transducers involved in tumour cell motility, including paxillin, were also efficiently inhibited by the combination therapy, as demonstrated by western blot and confocal microscopy assays. Moreover, these combined treatments inhibited tumour growth and increased animal survival in nude mice xenografted with SuR RCC cells. Finally, lung micrometastasis formation was reduced when mice were treated with NVP-LDE225 plus everolimus or sunitinib, as evidenced by artificial metastatic assays.

Conclusions:

Hedgehog inhibition by NVP-LDE225 plus sunitinib or everolimus bolsters antitumour activity by interfering with tumour growth and metastatic spread, even in SuR cells. Thus, this new evidence puts forward a new promising therapeutic approach for RCC patients.

Challenges and advances in mouse modeling for human pancreatic tumorigenesis and metastasis

Pancreatic cancer is critical for developed countries, where its rate of diagnosis has been increasing steadily annually. In the past decade, the advances of pancreatic cancer research have not contributed to the decline in mortality rates from pancreatic cancer-the overall 5-year survival rate remains about 5% low. This number only underscores an obvious urgency for us to better understand the biological features of pancreatic carcinogenesis, to develop early detection methods, and to improve novel therapeutic treatments. To achieve these goals, animal modeling that faithfully recapitulates the whole process of human pancreatic cancer is central to making the advancements. In this review, we summarize the currently available animal models for pancreatic cancer and the advances in pancreatic cancer animal modeling. We compare and contrast the advantages and disadvantages of three major categories of these models: (1) carcinogen-induced; (2) xenograft and allograft; and (3) genetically engineered mouse models. We focus more on the genetically engineered mouse models, a category which has been rapidly expanded recently for their capacities to mimic human pancreatic cancer and metastasis, and highlight the combinations of these models with various newly developed strategies and cell-lineage labeling systems.

DNA methylation and MeCP2 regulation of PTCH1 expression during rats hepatic fibrosis

Hepatic stellate cell (HSC) activation plays an important role in liver fibrogenesis. Transdifferentiation of quiescent hepatic stellate cells into myofibroblastic-HSCs is a key event in liver fibrosis. The methyl-CpG-binding protein MeCP2 which promotes repressed chromatin structure is selectively detected in myofibroblasts of diseased liver. MeCP2 binds to methylated CpG dinucleotides, which are abundant in the promoters of many genes. Treatment of HSCs with DNA methylation inhibitor 5-aza-2'- deoxycytidine (5-azadC) prevented proliferation and activation. Treatment with 5-azadC prevented loss of Patched (PTCH1) expression that occurred during HSCs activation. In a search for underlying molecular medchanisms, we investigated whether the targeting of epigenetic silencing mechanisms could be useful in the treatment of PTCH1-associated fibrogenesis. It was indicated that hypermethylation of PTCH1 is associated with the perpetuation of fibroblast activation and fibrosis in the liver. siRNA knockdown of MeCP2 increased the expressions of PTCH1 mRNA and protein in hepatic myofibroblasts. These data suggest that DNA methylation and MeCP2 may provide molecular mechanisms for silencing of PTCH1.