Paracrine sonic hedgehog signaling contributes significantly to acquired steroidogenesis in the prostate tumor microenvironment

Serine/threonine kinase 36 induced epithelial-mesenchymal transition promotes docetaxel resistance in prostate cancer

To investigate the role and potential mechanism of serine/threonine kinase 36 (STK36) in docetaxel resistance-prostate cancer (PCa). The expression of STK36 in PCa and the correlation with clinicopathological characteristics of PCa patients were analyzed using the data from different databases and tissue microarrays. To investigate the role of STK36 on cell proliferation, invasion, and migration, STK36 was overexpressed and silenced in DU-145 and PC-3 cell lines. Cell counting kit-8 (CCK8) was used to test cell proliferation. Cell invasion and migration were detected by cell wound scratch assay and trans well, respectively. The expression profile of STK36, E-Cadherin, and Vimentin was analyzed by Western blot. Cell apoptosis was detected by the TUNEL assay. STK36 expression was upregulated in PCa tissue compared with adjacent benign PCa tissue; it was higher in patients with advanced stages compared with lower stages and was significantly correlated with decreased overall survival. Up-regulation of STK36 significantly promoted the proliferation, invasion, and migration of DU-145 and PC-3 cells and compensated for the suppression caused by docetaxel treatment in vitro. A striking apoptosis inhibition could be observed when dealing with docetaxel, although the apoptosis of DU-145 and PC-3 cells was not affected by the STK36 exclusive overexpression. Besides, E-Cadherin expression was restrained while the expression levels of vimentin were all enhanced. The knockdown of STK36 reversed the above process. STK36 up-regulation could accelerate the biological behavior and docetaxel resistance of PCa by epithelial-mesenchymal transition (EMT) activation. STK36 may be potentially used as a target in PCa resolvent with docetaxel.

Prostate cancer patient stratification by molecular signatures in the Veterans Precision Oncology Data Commons

Veterans are at an increased risk for prostate cancer, a disease with extraordinary clinical and molecular heterogeneity, compared with the general population. However, little is known about the underlying molecular heterogeneity within the veteran population and its impact on patient management and treatment. Using clinical and targeted tumor sequencing data from the National Veterans Affairs health system, we conducted a retrospective cohort study on 45 patients with advanced prostate cancer in the Veterans Precision Oncology Data Commons (VPODC), most of whom were metastatic castration-resistant. We characterized the mutational burden in this cohort and conducted unsupervised clustering analysis to stratify patients by molecular alterations. Veterans with prostate cancer exhibited a mutational landscape broadly similar to prior studies, including KMT2A and NOTCH1 mutations associated with neuroendocrine prostate cancer phenotype, previously reported to be enriched in veterans. We also identified several potential novel mutations in PTEN, MSH6, VHL, SMO, and ABL1 Hierarchical clustering analysis revealed two subgroups containing therapeutically targetable molecular features with novel mutational signatures distinct from those reported in the Catalogue of Somatic Mutations in Cancer database. The clustering approach presented in this study can potentially be used to clinically stratify patients based on their distinct mutational profiles and identify actionable somatic mutations for precision oncology.

Targeting the hedgehog pathway in MET mutation cancers and its effects on cells associated with cancer development

The mutation of MET plays a crucial role in the initiation of cancer, while the Hedgehog (Hh) pathway also plays a significant role in cell differentiation and the maintenance of tumor stem cells. Conventional chemotherapy drugs are primarily designed to target the majority of cell populations within tumors rather than tumor stem cells. Consequently, after a brief period of remission, tumors often relapse. Moreover, the exclusive targeting of tumor stemness cell disregards the potential for other tumor cells to regain stemness and acquire drug resistance. As a result, current drugs that solely target the HGF/c-MET axis and the Hh pathway demonstrate only moderate efficacy in specific types of cancer. Mounting evidence indicates that these two pathways not only play important roles in cancer but also exert significant influence on the development of resistance to single-target therapies through the secretion of their own ligands. In this comprehensive review, we analyze and compare the potential impact of the Hh pathway on the tumor microenvironment (TME) in HGF/c-MET-driven tumor models, as well as the interplay between different cell types. Additionally, we further substantiate the potential and necessity of dual-pathway combination therapy as a critical target in MET addicted cancer treatment. Video Abstract.

A review of the occurrence, metabolites and health risks of butylated hydroxyanisole (BHA)

Butylated hydroxyanisole (BHA) is mainly used as a food additive due to its antioxidant properties, which prevent or delay oxidation reactions and extend the storage life of products. The widespread use of BHA has led to its extensive presence in various environmental matrices and human tissues. Food intake is the main route of human exposure to BHA. Under different conditions, BHA can produce different metabolites, with tert-butyl hydroquinone (TBHQ) being one of the major products. Several studies have shown that BHA could cause thyroid system damage, metabolic and growth disorders, neurotoxicity, and carcinogenesis. Mechanisms such as endocrine disruption, genotoxicity, disturbances of energy metabolism, reactive oxygen species (ROS) production, signaling pathways, and imbalances in calcium homeostasis appear to be associated with the toxic effects of BHA. Avoiding the toxic effects of BHA to the maximum extent possible is a top priority. Finding safe, non-toxic and environmentally friendly alternatives to BHA should be the focus of subsequent research. In all, this review summarized the current situation related to BHA and might make recommendations for future research directions. © 2023 Society of Chemical Industry.

Aberrant activation of the Hedgehog signaling pathway in granulosa cells from patients with polycystic ovary syndrome

The molecular mechanism that triggers polycystic ovary syndrome (PCOS) is mysterious. Abnormal development of ovarian granulosa cells (GCs) is one of the causes of PCOS. Herein, our study was carried out using RNA-seq to detect the different gene expression levels in ovarian GCs between three patients with PCOS and four normal controls. To verify the RNA-seq data, GCs from 22 patients with PCOS and 21 controls with normal ovulation were collected to perform the RT-PCR analysis. Hedgehog signaling pathway (Hh) members, Ihh and Ptch2 were abnormally highly expressed in the PCOS tissue (PT). The qPCR also indicated that the expression levels of Hh signaling pathway downstream members, Ptch1, Gli1, and Gli2 in the PT were significantly higher than those in the normal tissue (NT). Besides, the expression of TNF-α mRNA in PCOS patients was higher than that in the control group. Through the chromatin immunoprecipitation assay (ChIP), we found that the Gli1-IP-DNA enriched from the granular cells of PCOS patients was higher than that of the control group. Finally, the Hh signaling pathway inhibitor, cyclopamine, can decrease the apoptosis of PCOS ovarian granulosa cells. These results suggest that abnormal activation of Hh signaling pathway, especially Ihh signal, may have a profound influence on PCOS.

Hedgehog/GLI1 signaling pathway regulates the resistance to cisplatin in human osteosarcoma

Purpose: This study aimed to investigate the role and mechanism of Hedgehog/GLI1 signaling pathway in regulating the resistance to cisplatin in osteosarcoma (OS).

Materials and methods: Immunohistochemistry, western blotting and qRT-PCR assay were performed to analyze and compare the expression of GLI1 in OS tumor tissue and normal bone tissue as well as in cisplatin sensitive and resistant cell lines (SOSP-9607 and SOSP-9607/CR). Meanwhile, the biological role of GLI1 in OS was investigated by using down-regulated expression of GLI1 and functional assays, including CCK-8, colony formation assay, flow cytometry, and wound healing assay. Moreover, the relationship between GLI1 and γ-H2AX (DNA damage protein) in cells treated with GLI1 siRNA and cisplatin was examined using western blot analysis. In addition, GANT61, a inhibitor of Hedgehog pathway was used in xenograft tumor model to further verify the effect and mechanism of GLI1 on cisplatin resistance in OS.

Results: We showed that GLI1 expression was up-regulated in OS patients and cisplatin-resistant cells. Silencing GLI1 significantly restored the sensitivity of OS to cisplatin, reduced proliferation, migration and cloning capacity of cisplatin sensitive and resistant cells, and increased the apoptosis rate in vitro. Furthermore, combined administration of GANT61 and cisplatin markedly inhibitted tumor growth in the mouse model. Mechanitic studies found that γ-H2AX is involved in the cisplatin resistance, and blockade of Hedgehog/GLI1 pathway increased the expression of γ-H2AX.

Conclusion: Abnormal activation of Hedgehog-GLI1 pathway can regulate the expression of γ-H2AX, thus affecting DNA damage and repair functions, and promoting acquired cisplatin resistance of OS.

Effects of the Hedgehog Signaling Inhibitor Itraconazole on Developing Rat Ovaries

Early ovary development is considered to be largely hormone independent; yet, there are associations between fetal exposure to endocrine disrupting chemicals and reproductive disorders in women. This can potentially be explained by perturbations to establishment of ovarian endocrine function rather than interference with an already established hormone system. In this study we explore if Hedgehog (HH) signaling, a central pathway for correct ovary development, can be disrupted by exposure to HH-disrupting chemicals, using the antifungal itraconazole as model compound. In the mouse Leydig cell line TM3, used as a proxy for ovarian theca cells, itraconazole exposure had a suppressing effect on genes downstream of HH signaling, such as Gli1. Exposing explanted rat ovaries (gestational day 22 or postnatal day 3) to 30 µM itraconazole for 72 h induced significant suppression of genes in the HH signaling pathway with altered Ihh, Gli1, Ptch1, and Smo expression similar to those previously observed in Ihh/Dhh knock-out mice. Exposing rat dams to 50 mg/kg bw/day in the perinatal period did not induce observable changes in the offspring's ovaries. Overall, our results suggest that HH signal disruptors may affect ovary development with potential long-term consequences for female reproductive health. However, potent HH inhibitors would likely cause severe teratogenic effects at doses lower than those causing ovarian dysgenesis, so the concern with respect to reproductive disorder is for the presence of HH disruptors at low concentration in combination with other ovary or endocrine disrupting compounds.

Cell Plasticity and Prostate Cancer: The Role of Epithelial-Mesenchymal Transition in Tumor Progression, Invasion, Metastasis and Cancer Therapy Resistance

Simple Summary

Although epithelial-to-mesenchymal transition (EMT) is a well-known cellular process involved during normal embryogenesis and wound healing, it also has a dark side; it is a complex process that provides tumor cells with a more aggressive phenotype, facilitating tumor metastasis and even resistance to therapy. This review focuses on the key pathways of EMT in the pathogenesis of prostate cancer and the development of metastases and evasion of currently available treatments.

Abstract

Prostate cancer, the second most common malignancy in men, is characterized by high heterogeneity that poses several therapeutic challenges. Epithelial–mesenchymal transition (EMT) is a dynamic, reversible cellular process which is essential in normal embryonic morphogenesis and wound healing. However, the cellular changes that are induced by EMT suggest that it may also play a central role in tumor progression, invasion, metastasis, and resistance to current therapeutic options. These changes include enhanced motility and loss of cell–cell adhesion that form a more aggressive cellular phenotype. Moreover, the reverse process (MET) is a necessary element of the metastatic tumor process. It is highly probable that this cell plasticity reflects a hybrid state between epithelial and mesenchymal status. In this review, we describe the underlying key mechanisms of the EMT-induced phenotype modulation that contribute to prostate tumor aggressiveness and cancer therapy resistance, in an effort to provide a framework of this complex cellular process.

Smoothened loss is a characteristic of neuroendocrine prostate cancer

PURPOSE

Hedgehog (Hh) signaling promotes castration-resistant prostate cancer by supporting androgen-independent prostate cancer cell development and growth; however, its role in neuroendocrine prostate cancer (NEPC) has not yet been explored. In this study, we assessed the expression of key genes involved in Hh signaling in prostate cancer and investigated the potential role of smoothened (SMO) in the pathogenesis of NEPC.

METHODS

Six public datasets, each containing cases of prostate adenocarcinoma (AdPC) and NEPC, were analyzed to compare the differential messenger RNA (mRNA) expression of six classic Hh signaling genes. The SMO, synaptophysin, chromogranin A (CHGA) and androgen receptor (AR) proteins were evaluated in human tissues from 5 cases of NEPC, 2 cases of AdPC mixed with NEPC, 2 cases of AdPC with neuroendocrine differentiation and 22 cases of high-grade AdPC as determined by an immunohistochemistry assay. Gene set enrichment analysis (GSEA) was performed to identify relevant genetic signatures associated with SMO expression based on the public datasets. Stable SMO-knockdown LNCaP and C4-2B cells were established with a lentiviral system, and the expression of SMO, Gli1, AR, prostate-specific antigen (PSA), and REST was assessed by real-time polymerase chain reaction and western blot. Secreted PSA in the conditioned medium was assessed by ELISA. Gli1 was ectopically expressed performed by the transfection of Gli1 complementary DNA into SMO-knockdown LNCaP cells, and western blot was used to assess of AR and PSA expression.

RESULTS

The mRNA level of SMO was dramatically downregulated in NEPC samples compared with AdPC samples in all 6 public datasets. SMO protein loss was observed in 100% of NEPC samples but in only 9% (2 of 22) of high-grade AdPC samples. GSEA results showed that SMO loss was closely correlated with AR signaling activity. Stable SMO knockdown significantly attenuated AR signaling activity and suppressed AR expression, while Gli1 overexpression partially reversed the inhibitory effects of SMO knockdown on AR signaling activity and AR expression in LNCaP and C4-2B cells.

CONCLUSION

These results demonstrate that SMO loss is a characteristic of NEPC and that detecting SMO by IHC could aid pathologists in NEPC diagnosis. SMO loss may promote NEPC pathogenesis by modulating AR signaling.

SEMA3C induces androgen synthesis in prostatic stromal cells through paracrine signaling

BACKGROUND

Castration resistant prostate cancer progression is associated with an acquired intratumoral androgen synthesis. Signaling pathways that can upregulate androgen production in prostate tumor microenvironment are not entirely known. In this study, we investigate the potential effect of a secreted signaling protein named semaphorin 3C (SEMA3C) on steroidogenic activities of prostatic stromal cells.

METHODS

We treated human primary prostate stromal cells (PrSC) with 1uM recombinant SEMA3C protein and androgen precursor named dehydroepiandrosterone (DHEA) 1.7uM. Also, to test SEMA3C's effect on the conversion of DHEA to androgens, we exposed PrSCs to the conditioned media derived from LNCaP cells that were transduced with a lentiviral vector harboring full length SEMA3C gene or empty vector (CM-LN^SEMA3C or CM-LN^Vector ). Then, liquid chromatography-mass spectrometry was performed on steroids isolated from PrSCs media. The messnger RNA expression of steroidogenic enzymes in PrSCs was quantified by quantitative polymerase chain reaction.

RESULTS

Recombinant SEMA3C had no effect on steroidogenic activities in PrSCs. However, key steroidogenic enzymes expression and androgen synthesis were upregulated in PrSCs treated with CM-LN^SEMA3C , compared to those treated with CM-LN^Vector . These results suggest that steroidogenic activities in PrSCs were upregulated in response to a signaling factor in CM-LN^SEMA3C , other than SEMA3C. We hypothesized that SEMA3C overexpression in LNCaP cells affected androgen synthesis in PrSCs through sonic hedgehog (Shh) pathway activation in PrSCs. We verified this effect by blocking Shh signaling with smoothened antagonist.

CONCLUSION

Based on known ability of Shh signaling pathway to activate steroidogenesis in stromal cells, we suggest that SEMA3C overexpression in LNCaP cells can upregulate Shh which in turn is able to stimulate steroidogenic activities in prostatic stromal cells.

Shh Overexpression Is Correlated with GRP78 and AR Expression in Primary Prostate Cancer: Clinicopathological Features and Outcomes in a Chinese Cohort

Introduction

Shh plays an important role in prostate cancer progression, but its correlation with GRP78 and AR is elusive.

Methods

The study included 539 patients in total, of which 443 had primary prostate carcinoma and 96 patients had benign prostatic hyperplasia (BPH). The clinicopathologic features, histologic scores of protein expression, and correlations between protein and disease state were studied in this cohort. Kaplan–Meier and Pearson correlation analyses were used to compare measures between groups. We performed immunohistochemistry to evaluate the expression of the Shh protein in benign prostatic hyperplasia (n=96) and prostate cancer (Gleason scores ≤6 [n=399] or ≥7 [n=44]). We quantified the expression of Shh, AR, and GRP78 using the weighted histoscore method, studied the correlation between Shh expression and AR and GRP78, and evaluated the impact of Shh protein expression on patient survival.

Results

Shh expression was significantly higher in prostate cancer with Gleason scores ≥7 than in cancer with lower Gleason scores or benign hyperplasia and was much higher in AR-positive cancer than in AR-negative cancer. Shh is overexpressed in high-grade prostate cancer and is positively correlated with the expression of both GRP78 and AR.

Conclusion

Therefore, Shh may be a useful prognostic marker and therapeutic target for prostate cancer.

Transient Sox9 Expression Facilitates Resistance to Androgen-Targeted Therapy in Prostate Cancer

PURPOSE

Patients with metastatic prostate cancer are increasingly presenting with treatment-resistant, androgen receptor-negative/low (AR^-/Low) tumors, with or without neuroendocrine characteristics, in processes attributed to tumor cell plasticity. This plasticity has been modeled by Rb1/p53 knockdown/knockout and is accompanied by overexpression of the pluripotency factor, Sox2. Here, we explore the role of the developmental transcription factor Sox9 in the process of prostate cancer therapy response and tumor progression.

EXPERIMENTAL DESIGN

Unique prostate cancer cell models that capture AR^-/Low stem cell-like intermediates were analyzed for features of plasticity and the functional role of Sox9. Human prostate cancer xenografts and tissue microarrays were evaluated for temporal alterations in Sox9 expression. The role of NF-κB pathway activity in Sox9 overexpression was explored.

RESULTS

Prostate cancer stem cell-like intermediates have reduced Rb1 and p53 protein expression and overexpress Sox2 as well as Sox9. Sox9 was required for spheroid growth, and overexpression increased invasiveness and neural features of prostate cancer cells. Sox9 was transiently upregulated in castration-induced progression of prostate cancer xenografts and was specifically overexpressed in neoadjuvant hormone therapy (NHT)-treated patient tumors. High Sox9 expression in NHT-treated patients predicts biochemical recurrence. Finally, we link Sox9 induction to NF-κB dimer activation in prostate cancer cells.

CONCLUSIONS

Developmentally reprogrammed prostate cancer cell models recapitulate features of clinically advanced prostate tumors, including downregulated Rb1/p53 and overexpression of Sox2 with Sox9. Sox9 is a marker of a transitional state that identifies prostate cancer cells under the stress of therapeutic assault and facilitates progression to therapy resistance. Its expression may index the relative activity of the NF-κB pathway.

Hedgehog Signaling for Urogenital Organogenesis and Prostate Cancer: An Implication for the Epithelial-Mesenchyme Interaction (EMI)

Hedgehog (Hh) signaling is an essential growth factor signaling pathway especially in the regulation of epithelial-mesenchymal interactions (EMI) during the development of the urogenital organs such as the bladder and the external genitalia (EXG). The Hh ligands are often expressed in the epithelia, affecting the surrounding mesenchyme, and thus constituting a form of paracrine signaling. The development of the urogenital organ, therefore, provides an intriguing opportunity to study EMI and its relationship with other pathways, such as hormonal signaling. Cellular interactions of prostate cancer (PCa) with its neighboring tissue is also noteworthy. The local microenvironment, including the bone metastatic site, can release cellular signals which can affect the malignant tumors, and vice versa. Thus, it is necessary to compare possible similarities and divergences in Hh signaling functions and its interaction with other local growth factors, such as BMP (bone morphogenetic protein) between organogenesis and tumorigenesis. Additionally, this review will discuss two pertinent research aspects of Hh signaling: (1) the potential signaling crosstalk between Hh and androgen signaling; and (2) the effect of signaling between the epithelia and the mesenchyme on the status of the basement membrane with extracellular matrix structures located on the epithelial-mesenchymal interface.

Safety and Tolerability of Sonic Hedgehog Pathway Inhibitors in Cancer

The hedgehog pathway, for which sonic hedgehog (Shh) is the most prominent ligand, is highly conserved and is tightly associated with embryonic development in a number of species. This pathway is also tightly associated with the development of several types of cancer, including basal cell carcinoma (BCC) and acute promyelocytic leukemia, among many others. Inactivating mutations in Patched-1 (PTCH1), leading to ligand-independent pathway activation, are frequent in several cancer types, but most prominent in BCC. This has led to the development of several compounds targeting this pathway as a cancer therapeutic. These compounds target the inducers of this pathway in Smoothened (SMO) and the GLI transcription factors, although targeting SMO has had the most success. Despite the many attempts at targeting this pathway, only three US FDA-approved drugs for cancers affect the Shh pathway. Two of these compounds, vismodegib and sonidegib, target SMO to suppress signaling from either PTCH1 or SMO mutations that lead to upregulation of the pathway. The other approved compound is arsenic trioxide, which can suppress this pathway at the level of the GLI proteins, although current evidence suggests it also has other targets. This review focuses on the safety and tolerability of these clinically approved drugs targeting the Shh pathway, along with a discussion on other Shh pathway inhibitors being developed.

Tetrazole hybrids with potential anticancer activity

Cancer is one of the main causes of death throughout the world. The anticancer agents are indispensable for the treatment of various cancers, but most of them currently on the market are not specific, resulting in series of side effects of chemotherapy. Moreover, the emergency of drug-resistance towards cancers has already increased up to alarming level in the recent decades. Therefore, it's imperative to develop novel anticancer candidates with excellent activity against both drug-susceptible and drug-resistant cancers, and low toxicity as well. Tetrazole is the bioisoster of carboxylic acid, and its derivatives demonstrated promising anticancer activity. Hybridization of tetrazole with other anticancer pharmacophores may provide novel candidates with anticancer potency. The present review described the anticancer activity of tetrazole hybrids, and the structure-activity relationship (SAR) is also discussed to provide an insight for rational designs of tetrazole anticancer candidates with higher efficiency.

Novel-smoothened inhibitors for therapeutic targeting of naïve and drug-resistant hedgehog pathway-driven cancers

The G protein-coupled receptor (GPCR) smoothened (SMO) is a key signaling component of the sonic hedgehog (Hh) pathway and a clinically validated target for cancer treatment. The FDA-approved SMO inhibitors GDC-0449/Vismodegib and LDE225/Sonidegib demonstrated clinical antitumor efficacy. Nevertheless, relatively high percentage of treated patients would eventually develop acquired cross resistance to both drugs. Here, based on published structure and activity of GDC-0449 inhibitor class, we replaced its amide core with benzimidazole which retained bulk of the SMO-targeting activity as measured in our Hh/SMO/Gli1-reporter system. Synthesis and screening of multiple series of benzimidazole derivatives identified HH-1, HH-13, and HH-20 with potent target suppression (IC₅₀: <0.1 μmol/L) in the reporter assays. In NIH3T3 cells stimulated with a secreted Hh (SHH), these inhibitors dose dependently reduced mRNA and protein expression of the endogenous pathway components PTCH-1, Gli1, and cyclin D1 resulting in growth inhibition via G₀/G₁ arrest. Mechanistically, the SMO-targeted growth inhibition involved downregulation of mTOR signaling inputs and readouts consistent with diminished mTORC1/mTORC2 functions and apoptosis. In mice, as with GDC-0449, orally administered HH inhibitors blocked paracrine activation of stromal Hh pathway in Calu-6 tumor microenvironment and attenuated growth of PTCH^+/-/P53^-/- medulloblastoma allograft tumors. Furthermore, HH-13 and HH-20 potently targeted the drug-resistant smoothened SMO-D473H (IC₅₀: <0.2 μmol/L) compared to the poor inhibition by GDC-0449 (IC₅₀: >60 μmol/L). These results identify HH-13 and HH-20 as potent inhibitors capable of targeting naïve and drug-resistant Hh/SMO-driven cancers. The current leads may be optimized to improve pharmaceutical property for potential development of new therapy for treatment of Hh pathway-driven cancers.

Canonical and Noncanonical Androgen Metabolism and Activity

Androgens are critical drivers of prostate cancer. In this chapter we first discuss the canonical pathways of androgen metabolism and their alterations in prostate cancer progression, including the classical, backdoor and 5α-dione pathways, the role of pre-receptor DHT metabolism, and recent findings on oncogenic splicing of steroidogenic enzymes. Next, we discuss the activity and metabolism of non-canonical 11-oxygenated androgens that can activate wild-type AR and are less susceptible to glucuronidation and inactivation than the canonical androgens, thereby serving as an under-recognized reservoir of active ligands. We then discuss an emerging literature on the potential non-canonical role of androgen metabolizing enzymes in driving prostate cancer. We conclude by discussing the potential implications of these findings for prostate cancer progression, particularly in context of new agents such as abiraterone and enzalutamide, which target the AR-axis for prostate cancer therapy, including mechanisms of response and resistance and implications of these findings for future therapy.

Evaluation of NCAM and c-Kit as hepatic progenitor cell markers for intrahepatic cholangiocarcinomas

BACKGROUND

Intrahepatic cholangiocarcinomas (ICCs) are primary liver malignancies and are the second most common type of malignancy after hepatocellular carcinoma. ICCs are heterogeneous in clinical features, genotype, and biological behavior, suggesting that ICCs can initiate in different cell lineages.

AIM

We investigated intrahepatic cholangiocarcinoma RBE cell lines for the markers neural cell adhesion molecule (NCAM) and c-Kit, which possess hepatic progenitor cells properties.

METHODS

NCAM + c-Kit + cells were tested for hepatic progenitor cell properties including proliferation ability, colony formation, spheroid formation, and invasiveness in NOD/SCID mice. The Agilent Whole Human Genome Microarray Kit was used to evaluate differences in gene expression related to stem cell signaling pathways between NCAM + c-Kit + and NCAM-c-Kit- subset cells. Microarray results were further confirmed by real-time RT-PCR.

RESULTS

NCAM + c-Kit + cells showed hepatic progenitor cell-like traits including the abilities to self-renew and differentiate and tumorigenicity in NOD/SCID mice. Differences were observed in the expression of 421 genes related to stem cell signaling pathways (fc ≥ 2 or fc ≤ 0.5), among which 231 genes were upregulated and 190 genes were downregulated.

CONCLUSION

NCAM + c-Kit + subset cells in RBE may have properties of hepatic progenitor cells. NCAM combined with c-Kit may be a valuable marker for isolating and purifying ICC stem/progenitor cells.

Non-canonical activation of hedgehog in prostate cancer cells mediated by the interaction of transcriptionally active androgen receptor proteins with Gli3

Hedgehog (Hh) is an oncogenic signaling pathway that regulates the activity of Gli transcription factors. Canonical Hh is a Smoothened- (Smo-) driven process that alters the post-translational processing of Gli2/Gli3 proteins. Though evidence supports a role for Gli action in prostate cancer (PCa) cell growth and progression, there is little indication that Smo is involved. Here we describe a non-canonical means for activation of Gli transcription in PCa cells mediated by the binding of transcriptionally-active androgen receptors (ARs) to Gli3. Androgens stimulated reporter expression from a Gli-dependent promoter in a variety of AR + PCa cells and this activity was suppressed by an anti-androgen, Enz, or by AR knockdown. Androgens also upregulated expression of endogenous Gli-dependent genes. This activity was associated with increased intranuclear binding of Gli3 to AR that was antagonized by Enz. Fine mapping of the AR binding domain on Gli2 showed that AR recognizes the Gli protein processing domain (PPD) in the C-terminus. Mutations in the arginine-/serine repeat elements of the Gli2 PPD involved in phosphorylation and ubiquitinylation blocked the binding to AR. β-TrCP, a ubiquitin ligase that recognizes the Gli PPD, competed with AR for binding to this site. AR binding to Gli3 suppressed its proteolytic processing to the Gli3 repressor form (Gli3R) whereas AR knockdown increased Gli3R. Both full-length and truncated ARs were able to activate Gli transcription. Finally, we found that an ARbinding decoy polypeptide derived from the Gli2 C-terminus can compete with Gli3 for binding to AR. Exogenous overexpression of this decoy suppressed Gli transcriptional activity in PCa cells. Collectively, this work identifies a novel pathway for non-canonical activation of Hh signaling in PCa cells and identifies a means for interference that may have clinical relevance for PCa patients.

Old Sonic Hedgehog, new tricks: a new paradigm in thoracic malignancies

The Sonic Hedgehog (Shh) pathway is physiologically involved during embryogenesis, but is also activated in several diseases, including solid cancers. Previous studies have demonstrated that the Shh pathway is involved in oncogenesis, tumor progression and chemoresistance in lung cancer and mesothelioma. The Shh pathway is also closely associated with epithelial-mesenchymal transition and cancer stem cells. Recent findings have revealed that a small proportion of lung cancer cells expressed an abnormal full-length Shh protein, associated with cancer stem cell features. In this paper, we review the role of the Shh pathway in thoracic cancers (small cell lung cancer, non-small cell lung cancer, and mesothelioma) and discuss the new perspectives of cancer research highlighted by the recent data of the literature.