On the role of transforming growth factor-beta in the growth inhibitory effects of retinoic acid in human pancreatic cancer cells

Oncogenic signaling pathways in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the most common (∼90% cases) pancreatic neoplasm and one of the most lethal cancer among all malignances. PDAC harbor aberrant oncogenic signaling that may result from the multiple genetic and epigenetic alterations such as the mutation in driver genes (KRAS, CDKN2A, p53), genomic amplification of regulatory genes (MYC, IGF2BP2, ROIK3), deregulation of chromatin-modifying proteins (HDAC, WDR5) among others. A key event is the formation of Pancreatic Intraepithelial Neoplasia (PanIN) that often results from the activating mutation in KRAS. Mutated KRAS can direct a variety of signaling pathways and modulate downstream targets including MYC, which play an important role in cancer progression. In this review, we discuss recent literature shedding light on the origins of PDAC from the perspective of major oncogenic signaling pathways. We highlight how MYC directly and indirectly, with cooperation with KRAS, affect epigenetic reprogramming and metastasis. Additionally, we summarize the recent findings from single cell genomic approaches that highlight heterogeneity in PDAC and tumor microenvironment, and provide molecular avenues for PDAC treatment in the future.

The role of lncRNA Meg3 in the proliferation of all-trans retinoic acid-treated mouse embryonic palate mesenchymal cells involves the Smad pathway

Mesenchymal cell proliferation is critical for the growth of the palate shelf. All-trans retinoic acid (atRA), as well as pathways associated with TGF-β/Smad signaling, play crucial roles in the proliferation of mouse embryonic palate mesenchymal (MEPM) cells. We have found that MEPM-cell proliferation was regulated by atRA and exogenous TGF-β3 could significantly antagonize the atRA-mediated suppression of MEPM cell proliferation, which is closely associated with the regulation of TGF-β/Smad signaling pathway. The long non-coding RNA (lncRNA) MEG3 has been reported to activate TGF-β/Smad signaling, thereby regulating cellular proliferation, differentiation, and related processes. Here, we found that Meg3 expression increased significantly in atRA-treated MEPM cells while TGF-β3 treatment markedly inhibited Meg3 expression and antagonized the effect of atRA on Meg3. Moreover, Smad2 was found to interact directly with Meg3, and atRA treatment significantly enriched Meg3 in Smad2-immunoprecipitated samples. After Meg3 deletion, the effects of atRA on the proliferation of MEPM cells and TGF-β3-dependent protein expression were lost. Hence, we speculate that Meg3 has a role in the RA-induced suppression of MEPM cell proliferation by targeting Smad2 and thereby mediating TGF-β/Smad signaling inhibition.

Histoepigenetic analysis of the mesothelin network within pancreatic ductal adenocarcinoma cells reveals regulation of retinoic acid receptor gamma and AKT by mesothelin

To enable computational analysis of regulatory networks within the cancer cell in its natural tumor microenvironment, we develop a two-stage histoepigenetic analysis method. The first stage involves iterative computational deconvolution to estimate sample-specific cancer-cell intrinsic expression of a gene of interest. The second stage places the gene within a network module. We validate the method in simulation experiments, show improved performance relative to differential expression analysis from bulk samples, and apply it to illuminate the role of the mesothelin (MSLN) network in pancreatic ductal adenocarcinoma (PDAC). The network analysis and subsequent experimental validation in a panel of PDAC cell lines suggests AKT activation by MSLN through two known activators, retinoic acid receptor gamma (RARG) and tyrosine kinase non receptor 2 (TNK2). Taken together, these results demonstrate the potential of histoepigenetic analysis to reveal cancer-cell specific molecular interactions directly from patient tumor profiles.

Alteration of Transforming Growth Factor β Signaling Pathway Predicts Worse Prognosis in Pancreatic Ductal Adenocarcinoma

OBJECTIVES

Transforming growth factor β (TGF-β) signaling pathway is one of the core pathways in pancreatic ductal adenocarcinoma (PDAC). Prognostic value of TGF-β pathway genes as a functionally related group in PDAC is rarely studied.

METHODS

Seventy-two PDAC patients who underwent surgery between November 30, 2015, and September 13, 2017, in West China Hospital, Sichuan University, were identified and included in this study. Whole-exome sequencing or targeted next-generation sequencing was performed with tumor tissue. Clinicopathologic characteristics and survival data were retrospectively collected and analyzed.

RESULTS

Genetic alterations were detected in 71 patients (98.6%). Although 1 patient (1.4%) had one genetic alteration, 33 patients (45.8%) had 2 to 4 alterations and 37 patients (51.4%) had 5 or more alterations. Twenty-five patients with TGF-β pathway alteration were identified as TGF-βm+ group. Other 47 patients were TGF-βm- group. Mutation of TGF-β pathway was independently associated with inferior survival (hazard ratio, 2.22, 95% confidence interval, 1.05-4.70, P = 0.04), especially in patients accepting radical surgery (hazard ratio, 3.25, 95% confidence interval, 1.01-10.49, P = 0.04).

CONCLUSIONS

Inferior prognosis was observed in PDACs with mutations of TGF-β pathway. Genomic information could help screen out patients at risk after surgery, and adjuvant therapy might benefit this subgroup of PDACs.

Transforming growth factor-β signaling, a potential mechanism associated with diabetes mellitus and pancreatic cancer?

Pancreatic cancer is a common malignant digestive disease. Epidemiological and clinical studies have demonstrated that pancreatic cancer is closely related to diabetes mellitus. Diabetic patients are more likely to develop pancreatic cancer, which is linked with poor outcomes. Pancreatic cancer is complicated with abnormal blood sugar and insulin resistance and promotes the development of diabetes mellitus. Understanding the molecular mechanisms linking diabetes mellitus and pancreatic cancer is essential for the treatment of diabetes cancer patients. The transforming growth factor-β (TGF-β) signaling pathway is deregulated in cancer and has a dual role in different stages of cancer as a suppressor or a promoter. More important, The TGF-β signaling pathway is also another important reason for diabetic complications. This review summarizes the relationship between diabetes and pancreatic cancer, in particular, focusing on the role of the TGF-β signaling pathway. It is possible to find drugs like metformin that can prevent and treat pancreatic cancer by targeting the TGF-β signaling pathway.

Inflammatory Role of Cancer-Associated Fibroblasts in Invasive Breast Tumors Revealed Using a Fibrous Polymer Scaffold

Inflammation in cancer fuels metastasis and worsens prognosis. Cancer-associated fibroblasts (CAFs) present in the tumor stroma play a vital role in mediating the cascade of cancer inflammation that drives metastasis by enhancing angiogenesis, tissue remodeling, and invasion. In vitro models that faithfully recapitulate CAF-mediated inflammation independent of coculturing with cancer cells are nonexistent. We have engineered fibrous matrices of poly(ε-caprolactone) (PCL) that can maintain the manifold tumor-promoting properties of patient-derived CAFs, which would otherwise require repetitive isolation and complex coculturing with cancer cells. On these fibrous matrices, CAFs proliferated and remodeled the extracellular matrix (ECM) in a parallel-patterned manner mimicking the ECM of high-grade breast tumors and induced stemness in breast cancer cells. The response of the fibroblasts was observed to be sensitive to the scaffold architecture and not the polymer composition. The CAFs cultured on fibrous matrices exhibited increased activation of the NF-κB pathway and downstream proinflammatory gene expression compared to CAFs cultured on conventional two-dimensional (2D) dishes and secreted higher levels of proinflammatory cytokines such as IL-6, GM-CSF, and MIP-3α. Consistent with this, we observed increased infiltration of inflammatory cells to the tumor site and enhanced invasiveness of the tumor in vivo when tumor cells were injected admixed with CAFs grown on fibrous matrices. These data suggest that CAFs better retain their tumor-promoting proinflammatory properties on fibrous polymeric matrices, which could serve as a unique model to investigate the mechanisms of stroma-induced inflammation in cancer progression.

TGF-β in pancreatic cancer initiation and progression: two sides of the same coin

Pancreatic cancer is highly lethal malignant tumor with characterised rapid progression, invasiveness and resistance to radiochemotherapy. Transforming growth factor-β (TGF-β) signaling plays a dual role in both pro-tumorigenic and tumor suppressive of pancreatic cancer, depending on tumor stage and microenvironment. TGF-β signaling components alteration are common in pancreatic cancer, and its leading role in tumor formation and metastases has received increased attention. Many therapies have investigated to target TGF-β signaling in the preclinical and clinical setting. In this review, we highlight the dual roles of TGF-β and touch upon the perspectives on therapeutic target of TGF-β signaling in pancreatic cancer.

Nanoparticles for targeted delivery of therapeutics and small interfering RNAs in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the 5^th most common malignancy which is responsible for more than half million annual mortalities; also, it is the third leading cause of cancer related death. Unfavorable systemic side-effects of chemotherapeutic agents and susceptibility to the degradation of small interfering RNAs (siRNAs), which can knock down a specific gene involved in the disease, have hampered their clinical application. So, it could be beneficial to develop an efficient carrier for the stabilization and specific delivery of drugs and siRNA to cells. Targeted nanoparticles have gained considerable attention as an efficient drug and gene delivery system, which is due to their capability in achieving the highest accumulation of cytotoxic agents in tumor tissue, modifiable drug pharmacokinetic- and bio-distribution, improved effectiveness of treatment, and limited side-effects. Recent studies have shed more light on the advantages of novel drug loaded carrier systems vs free drugs. Most of the animal studies have reported improvement in treatment efficacy and survival rate using novel carrier systems. Targeted delivery may be achieved passively or actively. In passive targeting, no ligand as homing device is used, while targeting is achieved by incorporating the therapeutic agent into a macromolecule or nanoparticle that passively reaches the target organ. However, in active targeting, the therapeutic agent or carrier system is conjugated to a tissue or cell-specific receptor which is over-expressed in a special malignancy using a ligand called a homing device. This review covers a broad spectrum of targeted nanoparticles as therapeutic and non-viral siRNA delivery systems, which are developed for enhanced cellular uptake and targeted gene silencing in vitro and in vivo and their characteristics and opportunities for the clinical applications of drugs and therapeutic siRNA are discussed in this article. Asialoglycoprotein receptors, low-density lipoprotein, ganglioside GM1 cell surface ligand, epidermal growth factor receptor receptors, monoclonal antibodies, retinoic acid receptors, integrin receptors targeted by Arg-Gly-Asp peptide, folate, and transferrin receptors are the most widely studied cell surface receptors which are used for the site specific delivery of drugs and siRNA-based therapeutics in HCC and discussed in detail in this article.

Retinoic Acid Reduces Stem Cell-Like Features in Pancreatic Cancer Cells

OBJECTIVES

Retinoic acid (RA) has important functions during embryonic development being involved in cell growth and differentiation. Although approved for the treatment of acute promyelocytic leukemia, it is still under investigation for different solid tumors including pancreatic cancer. The objective of this study was to analyze how RA affects pancreatic cancer stem cells and how its combination with chemotherapy could impact cell growth.

METHODS

Using different pancreatic cancer cell lines, we evaluated the effect of RA alone or in combination with chemotherapy regulating cancer stem cells properties and pathways.

RESULTS

Retinoic acid treatment reduces the expression of pancreatic stem cell markers CD24, CD44, CD133, and aldehyde dehydrogenase 1 but not c-Met. Although gemcitabine treatment increases the expression of some of these markers especially CD44 when it is combined with RA, a notable reduction in all of them is observed. Retinoic acid induces a G0/G1 arrest and combined with gemcitabine increases the apoptotic effect produced by chemotherapy probably as a consequence of a regulation of specific stem cell transcription factors.

CONCLUSIONS

Retinoic acid regulates self-renewal capacity of cells in pancreatic tumors and should be further investigated in combination with chemotherapy as therapeutic strategy in pancreatic cancer.

All-Trans Retinoic Acid Induces TGF-β2 in Intestinal Epithelial Cells via RhoA- and p38α MAPK-Mediated Activation of the Transcription Factor ATF2

Objective

We have shown previously that preterm infants are at risk of necrotizing enterocolitis (NEC), an inflammatory bowel necrosis typically seen in infants born prior to 32 weeks’ gestation, because of the developmental deficiency of transforming growth factor (TGF)-β₂ in the intestine. The present study was designed to investigate all-trans retinoic acid (atRA) as an inducer of TGF-β₂ in intestinal epithelial cells (IECs) and to elucidate the involved signaling mechanisms.

Methods

AtRA effects on intestinal epithelium were investigated using IEC6 cells. TGF-β₂ expression was measured using reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) and Western blots. Signaling pathways were investigated using Western blots, transiently-transfected/transduced cells, kinase arrays, chromatin immunoprecipitation, and selective small molecule inhibitors.

Results

AtRA-treatment of IEC6 cells selectively increased TGF-β₂ mRNA and protein expression in a time- and dose-dependent fashion, and increased the activity of the TGF-β₂ promoter. AtRA effects were mediated via RhoA GTPase, Rho-associated, coiled-coil-containing protein kinase 1 (ROCK1), p38α MAPK, and activating transcription factor (ATF)-2. AtRA increased phospho-ATF2 binding to the TGF-β₂ promoter and increased histone H2B acetylation in the TGF-β₂ nucleosome, which is typically associated with transcriptional activation.

Conclusions

AtRA induces TGF-β₂ expression in IECs via RhoA- and p38α MAPK-mediated activation of the transcription factor ATF2. Further studies are needed to investigate the role of atRA as a protective/therapeutic agent in gut mucosal inflammation.

Retinoic acid improves morphology of cultured peritoneal mesothelial cells from patients undergoing dialysis

Patients undergoing continuous ambulatory peritoneal dialysis are classified according to their peritoneal permeability as low transporter (low solute permeability) or High transporter (high solute permeability). Factors that determine the differences in permeability between them have not been fully disclosed. We investigated morphological features of cultured human peritoneal mesothelial cells from low or high transporter patients and its response to All trans retinoic Acid (ATRA, vitamin A active metabolite), as compared to non-uremic human peritoneal mesothelial cells. Control cells were isolated from human omentum. High or low transporter cells were obtained from dialysis effluents. Cells were cultured in media containing ATRA (0, 50, 100 or 200 nM). We studied length and distribution of microvilli and cilia (scanning electron microscopy), epithelial (cytokeratin, claudin-1, ZO-1 and occludin) and mesenchymal (vimentin and α-smooth muscle actin) transition markers by immunofluorescence and Western blot, and transforming growth factor β1 expression by Western blot. Low and high transporter exhibited hypertrophic cells, reduction in claudin-1, occludin and ZO-1 expression, cytokeratin and vimentin disorganization and positive α-smooth muscle actin label. Vimentin, α-smooth muscle actin and transforming growth factor-β1 were overexpressed in low transporter. Ciliated cells were diminished in low and high transporters. Microvilli number and length were severely reduced in high transporter. ATRA reduced hypertrophic cells number in low transporter. It also improved cytokeratin and vimentin organization, decreased vimentin and α-smooth muscle actin expression, and increased claudin 1, occludin and ZO-1 expression, in low and high transporter. In low transporter, ATRA reduced transforming growth factor-β1 expression. ATRA augmented percentage of ciliated cells in low and high transporter. It also augmented cilia length in high transporter. Alterations in structure, epithelial mesenchymal markers and transforming growth factor-β1 expression were differential between low and high transporter. Beneficial effects of ATRA were improved human peritoneal mesothelial cells morphology tending to normalize structures.

Reversing the intractable nature of pancreatic cancer by selectively targeting ALDH-high, therapy-resistant cancer cells

Human pancreatic ductal adenocarcinoma (PDAC) is a cancer with a dismal prognosis. The efficacy of PDAC anticancer therapies is often short-lived; however, there is little information on how this disease entity so frequently gains resistance to treatment. We adopted the concept of cancer stem cells (CSCs) to explain the mechanism of resistance and evaluated the efficacy of a candidate anticancer drug to target these therapy-resistant CSCs. We identified a subpopulation of cells in PDAC with CSC features that were enriched for aldehyde dehydrogenase (ALDH), a marker expressed in certain stem/progenitor cells. These cells were also highly resistant to, and were further enriched by, treatment with gemcitabine. Similarly, surgical specimens from PDAC patients showed that those who had undergone preoperative chemo-radiation therapy more frequently displayed cancers with ALDH strongly positive subpopulations compared with untreated patients. Importantly, these ALDH-high cancer cells were sensitive to disulfiram, an ALDH inhibitor, when tested in vitro. Furthermore, in vivo xenograft studies showed that the effect of disulfiram was additive to that of low-dose gemcitabine when applied in combination. In conclusion, human PDAC-derived cells that express high levels of ALDH show CSC features and have a key role in the development of resistance to anticancer therapies. Disulfiram can be used to suppress this therapy-resistant subpopulation.

The characteristics of the expression of heat shock proteins and COX-2 in the liver of hamsters infected with Clonorchis sinensis, and the change of endocrine hormones and cytokines

The liver fluke Clonorchis sinensis (Digenea) is a high-risk parasite that causes serious diseases such as cirrhosis, carcinogenic liver damage and clonorchiasis in East Asia. This study was conducted to evaluate the relationship between stress/endocrine hormones and inflammation induced by infection as well as the expression of heat shock proteins (hsp-27, hsp-90), cox-2 and cytokines in the livers of hamsters infected with C. sinensis. The average body weight of infected hamsters decreased up to 25% compared with that of the control group, and bile duct hyperplasia with inflammation, liver fibrosis and hepatic necrosis were observed in C. sinensis-infected livers. The expression of hsp-27, hsp-90, and cox-2 was significantly increased in the livers of C. sinensis-infected hamsters compared with the control group. Moreover, the expression levels of inflammatory cytokines (IL-1beta, IL-2, TGF-beta2 and IFN-alpha1) were markedly increased in the livers of the infected group compared with those of the control group. Consistently, plasma IL-3 and IL-6 levels gradually increased during the infection period, and the concentration levels of testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), corticosterone, and adrenocorticotropic hormone (ACTH) in C. sinensis-infected hamsters increased over 25%, compared with those of the uninfected normal group. These results demonstrate that C. sinensis infection may increase the expression of hsp27, hsp90 and cox-2 as well as it may cause periductal fibrosis, chronic inflammation and hepatic necrosis in the liver. Furthermore, the results indicate that C. sinensis infection induces not only stress-induced hormone imbalance but also the sustained secretion of inflammatory cytokines through chronic stress/stimuli.

Retinoid and TGF-β families: crosstalk in development, neoplasia, immunity, and tissue repair

Transforming growth factor-β (TGF-β) isoforms are profibrotic cytokines, par excellence, and have complex multifunctional effects on many systems, depending on the biologic setting. Retinoids are vitamin A derivatives that also have diverse effects in development, physiology, and disease. The interactions between these classes of molecules are, not surprisingly, highly complex and are dependent on the tissue, cellular, and molecular settings.

Long non-coding RNA UCA1 regulated cell cycle distribution via CREB through PI3-K dependent pathway in bladder carcinoma cells

Long non-coding RNA urothelial carcinoma associated 1 (UCA1) promotes human bladder cancer cell proliferation, but the underlying mechanism remains unknown. After knocking down of UCA1 in BLZ-211 cells, several cell cycle-related genes (CDKN2B, EP300 and TGFβ-2) were screened by microarray assay and validated by real-time PCR. Interestingly, in western blot analysis, p300 (encoded by EP300) and its coactivator cAMP response element-binding protein (CREB) level were significantly down-regulated. Both suppression of UCA1 expression by shRNA in BLZ-211 cells and ectopic expression of UCA1 in UMUC-2 cells showed that UCA1 alteration paralleled to the expression and phosphorylation of CREB, and UCA1 obviously influenced AKT expression and activity. Furthermore, in BLZ-211 cells, cell cycle progression was greatly reduced after PI3-K pathway was blocked by LY294002, indicating that UCA1 affected cell cycle progression through CREB. Taken together, we concluded that UCA1 regulated cell cycle through CREB via PI3K-AKT dependent pathway in bladder cancer.

The novel triad of dorsal agenesis of the pancreas with concurrent pancreatic ductal adenocarcinoma and nonalcoholic chronic calcific pancreatitis: a case series and review of the literature

INTRODUCTION

Dorsal agenesis of the pancreas (DAP) is a rare congenital anomaly, with only 44 cases having been reported in the English literature since 1966.

MATERIALS AND METHODS

A retrospective review of our IRB-approved pancreatic surgery database was performed from November 2005 to November 2010 searching for cases of DAP.

DISCUSSION

Disorders in the retinoic acid (Raldh) and hedgehog (Hh) signaling pathways, which appear to play a role in the development of DAP, have been implicated in other diseases of the pancreas such as pancreatic ductal adenocarcinoma (PDA) and nonalcoholic chronic calcific pancreatitis (NCCP).

CONCLUSION

In this report, we describe three cases of DAP in the setting of PDA, two of which include the third component of NCCP. We provide a discussion of the clinical features of this novel triad and address the molecular pathways that relate to these respective diseases.

Adding a combination of hydroxycitrate and lipoic acid (METABLOC™) to chemotherapy improves effectiveness against tumor development: experimental results and case report

Altered metabolism of cancer first highlighted by Otto Warburg has a long history. Although ignored for a considerable amount of time, it is now receiving substantial attention. We recently published results obtained with a combination of two drugs, lipoic acid and hydroxycitrate, targeting metabolic enzymes particularly affected in cancer: ATP citrate lyase and pyruvate dehydrogenase kinase. This treatment was as efficient as chemotherapy in the three mouse cancer models that were tested. In this work, we asked if our drug combination could be used in conjunction with standard cytotoxic chemotherapy, in particular cisplatin, to improve basic protocol efficacy. A combination of lipoic acid and hydroxycitrate was administered to mice implanted with syngeneic cancer cells, LL/2 lung carcinoma and MBT-2 bladder carcinoma, concommitantly with classical chemotherapy (cisplatin or methotrexate). We demonstrate that the triple combination lipoic acid + hydroxycitrate + cisplatin or methotrexate is more efficient than cisplatin or methotrexate used individually or the combination of lipoic acid and hydroxycitrate administered alone. Of particular note are the results obtained in the treatment of an 80 year-old female who presented with ductal adenocarcinoma of the pancreas accompanied by liver metastases. A treatment course using gemcitabine plus α-lipoic acid and hydroxycitrate gave highly promising results. The in vivo data, coupled with the case study results, suggest a possible advantage in using a treatment targeted at cancer metabolism in association with classical chemotherapy.

ATRA in combination with nedaplatin inhibits cell proliferation but promotes apoptosis in human hepatoma cell line Huh-7

AIM: To observe the effects of all-trans retinoic acid (ATRA) and nedaplatin, alone or in combination, on cell proliferation and apoptosis in human hepatoma cell line Huh-7, and to determine whether the two drugs in combination have a synergistic effect in treating hepatocarcinoma.

METHODS: After Huh-7 cells were incubated with different concentrations of ATRA (10^-4, 10^-5 and 10^-6 mol/L) and nedaplatin (1, 2 and 5 mg/L), alone or in combination, for 24, 48 and 72 h, cell morphology changes were observed using an inverted microscope; cell proliferation was evaluated by MTT assay; and apoptosis was evaluated by flow cytometry.

RESULTS: Both ATRA and nedaplatin could markedly inhibit cell proliferation in a time- and concentration-dependent manner (all P < 0.01). ATRA and nedaplatin in combination had a significant synergistic effect on cell proliferation compared with ATRA or nedaplatin alone (both P < 0.01). Both ATRA and nedaplatin promoted the apoptosis of Huh-7 cells. The apoptosis rate was significantly lower in Huh-7 cells treated with ATRA and nedaplatin alone for 48 h than in those treated with the two drugs in combination (28.49% ± 0.6%, 42.57% ± 1.03% vs 55.35% ± 1.30%, both P < 0.01), suggesting a synergistic effect of combined nedaplatin and ATRA on the apoptosis of Huh-7 cells.

CONCLUSION: Both ATRA and nedaplatin can inhibit cell proliferation and promote apoptosis in human hepatoma cell line Huh-7. ATRA combined with nedaplatin has a significant synergistic effect on the proliferation and apoptosis of Huh-7 cells.

Prognostic significance of tumorigenic cells with mesenchymal features in pancreatic adenocarcinoma

BACKGROUND

Specific populations of highly tumorigenic cells are thought to exist in many human tumors, including pancreatic adenocarcinoma. However, the clinical significance of these tumor-initiating (ie, cancer stem) cells remains unclear. Aldehyde dehydrogenase (ALDH) activity can identify tumor-initiating cells and normal stem cells from several human tissues. We examined the prognostic significance and functional features of ALDH expression in pancreatic adenocarcinoma.

METHODS

ALDH expression was analyzed by immunohistochemistry in 269 primary surgical specimens of pancreatic adenocarcinoma and examined for association with clinical outcomes and in paired primary tumors and metastatic lesions from eight pancreatic cancer patients who had participated in a rapid autopsy program. The clonogenic growth potential of ALDH-positive pancreatic adenocarcinoma cells was assessed in vitro by a colony formation assay and by tumor growth in immunodeficient mice (10-14 mice per group). Mesenchymal features of ALDH-positive pancreatic tumor cells were examined by using quantitative reverse transcription-polymerase chain reaction and an in vitro cell invasion assay. Gene expression levels and the invasive potential of ADLH-positive pancreatic cancer cells relative to the bulk cell population were examined by reverse transcription-polymerase chain reaction and an in vitro invasion assays, respectively. All statistical tests were two-sided.

RESULTS

ALDH-positive tumor cells were detected in 90 of the 269 primary surgical specimens, and their presence was associated with worse survival (median survival for patients with ALDH-positive vs ALDH-negative tumors: 14 vs 18 months, hazard ratio of death = 1.28, 95% confidence interval = 1.02 to 1.68, P = .05). Six (75%) of the eight patients with matched primary and metastatic tumor samples had ALDH-negative primary tumors, and in four (67%) of these six patients, the matched metastatic lesions (located in liver and lung) contained ALDH-positive cells. ALDH-positive cells were approximately five- to 11-fold more clonogenic in vitro and in vivo compared with unsorted or ALHD-negative cells, expressed genes consistent with a mesenchymal state, and had in vitro migratory and invasive potentials that were threefold greater than those of unsorted cells.

CONCLUSIONS

ALDH expression marks pancreatic cancer cells that have stem cell and mesenchymal features. The enhanced clonogenic growth and migratory properties of ALDH-positive pancreatic cancer cells suggest that they play a key role in the development of metastatic disease that negatively affects the overall survival of patients with pancreatic adenocarcinoma.

Role of FGFR2-signaling in the pathogenesis of acne

It is the purpose of this review to extend our understanding of the fibroblast growth factor (FGF) receptor-2b-signaling network in the pathogenesis of acne. A new concept of the role of FGFR2b-signaling in dermal-epithelial interaction for skin appendage formation, pilosebaceous follicle homeostasis, comedogenesis, sebaceous gland proliferation and lipogenesis is presented. The FGFR2-gain-of-function mutations in Apert syndrome and unilateral acneiform nevus are most helpful model diseases pointing the way to androgen-dependent dermalepithelial FGFR2-signaling in acne. Androgen-mediated upregulation of FGFR2b-signaling in acne-prone skin appears to be involved in the pathogenesis of acne vulgaris. In organotypic skin cultures, keratinocyte-derived interleukin-1alpha stimulated fibroblasts to secrete FGF7 which stimulated FGFR2b-mediated keratinocyte proliferation. Postnatal deletion of FGFR2b in mice resulted in severe sebaceous gland atrophy. The importance of FGFR2b in sebaceous gland physiology is further supported by the mode of action of anti-acne agents which have been proposed to attenuate FGFR2b-signaling. Downregulation of FGFR2b-signaling by isotretinoin explains its therapeutic effect in acne. Downregulation of FGFR2b-signaling during the first trimester of pregnancy disturbs branched morphogenesis and explains retinoid embryotoxicity. Insulin-like growth factor-1 (IGF-1), the mediator of growth hormone during puberty, intracts with androgen-dependent FGFR2b-signaling and links androgen- and FGF-mediated signal transduction important in sebaceous gland homeostasis. The search for a follicular defect in the dermalepithelial regulation of growth factor-signaling in acne-prone skin appears to be a most promising approach to clarify the pathogenesis of acne.

Nuclear factor-kappaB enhances ErbB2-induced mammary tumorigenesis and neoangiogenesis in vivo

The (HER2/Neu) ErbB2 oncogene is commonly overexpressed in human breast cancer and is sufficient for mammary tumorigenesis in transgenic mice. Nuclear factor (NF)-kappaB activity is increased in both human and murine breast tumors. The immune response to mammary tumorigenesis may regulate tumor progression. The role of endogenous mammary epithelial cell NF-kappaB had not previously been determined in immune-competent animals. Furthermore, the role of the NF-kappaB components, p50 and p65, in tumor growth was not known. Herein, the expression of a stabilized form of the NF-kappaB-inhibiting IkappaBalpha protein (IkappaBalphaSR) in breast tumor cell lines that express oncogenic ErbB2 inhibited DNA synthesis and growth in both two- and three-dimensional cultures. Either NF-kappaB inhibition or selective silencing of p50 or p65 led to a loss of contact-independent tumor growth in vitro. IkappaBalphaSR reversed the features of the oncogene-induced phenotype under three-dimensional growth conditions. The NF-kappaB blockade inhibited ErbB2-induced mammary tumor growth in both immune-competent and immune-deficient mice. These findings were associated with both reduced tumor microvascular density and a reduction in the amount of vascular endothelial growth factor. The expression of IkappaBalphaSR in breast cancer tumors inhibited angiogenesis. Thus, mammary epithelial cell NF-kappaB activity enhances ErbB2-mediated mammary tumorigenesis in vivo by promoting both growth and survival signaling via the promotion of tumor vasculogenesis.

3beta-Hydroxysteroid dehydrogenases and pre-receptor steroid metabolism in the human ovarian surface epithelium

Ovulation-associated inflammation with accompanied cytokines and reproductive hormones impact upon the human ovarian surface epithelium (hOSE) and probably have a role in the aetiology of ovarian cancer. Progesterone and progestin-related events, i.e. pregnancy and oral contraception, protect from the disease. We have investigated the pre-receptor metabolism of progesterone in primary hOSE cells and an immortalised hOSE cell line, OSE-C2, focusing on transcriptional regulation of 3beta-hydroxysteroid dehydrogenase (3beta-HSD) by inflammatory, anti-inflammatory and apoptotic factors. In hOSE cells, we show that anti-inflammatory effects of IL-1alpha and IL-4 on 3beta-HSD2 mRNA involve a p38 MAPK signalling pathway, whereas pro-inflammatory response of IL-1alpha to 3beta-HSD1 mRNA involves a NF-kappaB inflammatory pathway. In OSE-C2 cells, retinoic acid and transforming growth factor-beta1 massively induce 3beta-HSD1 mRNA levels. In conclusion, we elaborate several mechanisms for intracrine formation of progesterone in hOSE that could contribute in the development of novel strategies to prevent, diagnose and/or treat ovarian cancer.

Holding their own: the noncanonical roles of Smad proteins

The identification of Smads as protein transcription factors in 1995 led to elucidation of the canonical transforming growth factor-beta (TGF-beta) signaling pathway. In the years that have followed, nuances of the pathway have been realized, and the once-simple scheme of ligand to receptor to activated transcription factor is now understood to be highly regulated at each step and riddled with crosstalk from other pathways. The Smads are also recognized as important players outside of canonical TGF-beta-dependent signaling and are responsible for regulating diverse cellular processes. New evidence suggests that Smad7 plays an integral role in maintaining cell-cell adhesion through direct regulation of beta-catenin. Receptor-activated Smads regulate the processing of a subset of microRNAs, particularly miR-21. The number of reports demonstrating the interactions of Smads with proteins outside of canonical TGF-beta signaling is increasing, although the functional relevance of these interactions is not known. Investigating these interactions will likely yield more evidence that Smads serve important and diverse purposes beyond their original reported function as signal transducers in the TGF-beta pathway.