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In colorectal cancer (CRC), macrophages represent a major component of the tumor mass and exert mostly functions promoting tumor cell survival, proliferation, and dissemination. Interleukin-34 (IL-34) is a cytokine overproduced by colon cancer (CRC) cells and supposed to make a valid contribution to the growth and diffusion of CRC cells. The biological functions of IL-34 are mediated by the macrophage colony-stimulating factor receptor (M-CSFR-1), which controls monocyte/macrophage differentiation, growth, and survival. We here investigated whether, in CRC, tumor-associated macrophages (TAMs) express M-CSFR-1 and functionally respond to IL-34. By flow-cytometry analysis of tumor-infiltrating cells (TICs) and lamina propria mononuclear cells (LPMCs) isolated from normal, adjacent mucosa of CRC patients, we showed that CD68/HLA-DRII-expressing TICs and LPMCs expressed M-CSFR-1. Both these cell types produced IL-34 even though the expression of the cytokine was more pronounced in TICs as compared to normal LPMCs. Moreover, in CRC samples, there was a positive correlation between IL-34-producing cells and CD68-positive cells. Stimulation of LPMCs and TICs with IL-34 resulted in enhanced expression of CD163 and CD206, two markers of type II-polarized macrophages, and this was evident at both RNA and protein level. In the same cell cultures, IL-34 stimulated expression and production of IL-6, a cytokine known to promote CRC cell growth and diffusion. Finally, knockdown of IL-34 in TICs with specific antisense oligonucleotides with: a specific antisesne oligonucleotide decreased IL-6 production and the number of TAMs producing this cytokine. This is the first to show a positive role of IL-34 in the control of TAMs in CRC, further supporting the notion that IL-34 sustains colon tumorigenesis.

Crohn’s disease (CD) and ulcerative colitis (UC), the main forms of inflammatory bowel disease (IBD) in human beings, are chronic relapsing-remitting disorders of the gastrointestinal tract, which usually require lifelong therapies. For many years, IBD have been managed with corticosteroids, aminosalicylates and immunosuppressants (ie, thiopurines). The advent of biologic therapies (anti-TNF-α agents) has significantly improved the outcome of IBD patients in terms of prolonged clinical remission, corticosteroid sparing, achievement of mucosal healing and prevention of disease-related complications. Nevertheless, primary failure or loss of response to biologics occur in about 50% of patients treated with these drugs. Therefore, the need for new effective treatments for such patients has critically emerged as an urgent priority. With this regard, several small-molecule drugs (SMDs) targeting lymphocyte trafficking (ie, sphingosine-1-phosphate receptor modulators) and the JAK/STAT pathway (eg, tofacitinib) have been recently developed and tested in IBD. In particular, JAK inhibitors are oral compounds characterized by short half-life, low antigenicity and the ability to dampen several pro-inflammatory pathways simultaneously. Tofacitinib, a pan-JAK inhibitor, has shown good efficacy and safety in UC clinical trials and has been recently approved for the treatment of UC patients. In this review, we analyze the main evidence supporting the use of JAK inhibitors in UC and explore the unanswered questions about the use of this class of drug in UC.

Background and AimThe mechanisms underlying the formation of intestinal fibrostrictures [FS] in Crohn’s disease [CD] are not fully understood, but activation of fibroblasts and excessive collagen deposition are supposed to contribute to the development of FS. Here we investigated whether interleukin-34 [IL-34], a cytokine that is over-produced in CD, regulates collagen production by gut fibroblastsMethodsIL-34 and its receptor macrophage colony-stimulating factor receptor 1 [M-CSFR-1] were evaluated in inflammatory [I], FS CD, and control [CTR] ileal mucosal samples by real-time polymerase chain reaction [RT-PCR], western blotting, and immunohistochemistry. IL-34 and M-CSFR-1 expression was evaluated in normal and FS CD fibroblasts. Control fibroblasts were stimulated with IL-34 in the presence or absence of a MAP kinase p38 inhibitor, and FS CD fibroblasts were cultured with a specific IL-34 antisense oligonucleotide, and collagen production was evaluated by RT-PCR, western blotting, and Sircol assay. The effect of IL-34 on the wound healing capacity of fibroblasts was evaluated by scratch test.ResultsWe showed enhanced M-CSFR-1 and IL-34 RNA and protein expression in FS CD mucosal samples as compared with ICD and CTR samples. Immunohistochemical analysis showed that stromal cells were positive for M-CSFR-1 and IL-34. Enhanced M-CSFR-1 and IL-34 RNA and protein expression was seen in FS CD fibroblasts as compared with CTR. Stimulation of control fibroblasts with IL-34 enhanced COL1A1 and COL3A1 expression and secretion of collagen through a p38 MAP kinase-dependent mechanism, and wound healing. IL-34 knockdown in FS CD fibroblasts was associated with reduced collagen production and wound repair.ConclusionsData indicate a prominent role of IL-34 in the control of intestinal fibrogenesis.

Background: Increased keratinocyte proliferation occurs in the skin of psoriatic patients and is supposed to play a role in the pathogenesis of this disorder. Compounds interfering with keratinocyte proliferation could be useful in the management of psoriatic patients. Aim: To investigate whether albendazole, an anti-helmintic drug that regulates epithelial cell function in various systems, inhibits keratinocyte proliferation in models of psoriasis. Methods: Aldara-treated mice received daily topical application of albendazole. Keratinocyte proliferation and keratin (K) 6 and K16 expression were evaluated by immunohistochemistry and Western blotting and inflammatory cells/mediators were analysed by immunohistochemistry and real-time PCR. In human keratinocytes (HEKa and HaCaT) treated with albendazole, cell cycle and proliferation, keratins and cell cycle-associated factors were evaluated by flow cytometry, colorimetric assay and Western blotting respectively. Results: Aldara-treated mice given albendazole exhibited reduced epidermal thickness, decreased number of proliferating keratinocytes and K6/K16 expression. Reduction of CD3- and Ly6G-positive cells in the skin of albendazole-treated mice associated with inhibition of IL-6, TNF-α, IL-1β, IL-17A, IL-36, CCL17, CXCL1, CXCL2 and CXCL5 expression. Treatment of keratinocytes with albendazole reduced K6/K16 expression and reversibly inhibited cell growth by promoting accumulation of cells in S-phase. This phenomenon was accompanied by down-regulation of CDC25A, a phosphatase regulating progression of cell cycle through S-phase, and PKR-dependent hyper-phosphorylation of eIF2α, an inhibitor of CDC25 translation. In Aldara-treated mice, albendazole activated PKR, enhanced eIF2α phosphorylation and reduced CDC25A expression. Conclusions: Data show that albendazole inhibits keratinocyte proliferation and exerts therapeutic effect in a murine model of psoriasis.

Background and AimsIntestinal barrier dysfunction is a hallmark of inflammatory bowel diseases [IBD], but the mechanisms that lead to such a defect are not fully understood. This study was aimed at characterising the factors involved in the defective barrier function in IBD.MethodsTranscriptome analysis was performed on colon samples taken from healthy controls [CTR] and IBD patients. Expression of GATA-binding factor 6 [GATA6], a transcription factor involved in intestinal epithelial cell differentiation, was evaluated in colon samples taken from CTR and IBD patients by real-time polymerase chain reaction [PCR] and immunohistochemistry. Intestinal sections of wild-type and Gata6del mice, which exhibit a conditional Gata6 deletion in intestinal epithelial cells and which are either left untreated or receive subcutaneous indomethacin or rectal trinitrobenzene sulphonic acid, were stained with haematoxylin and eosin. In parallel, some Gata6del mice received antibiotics to deplete intestinal flora. Mucosal inflammatory cell infiltration and cytokine production were evaluated by flow cytometry and real-time PCR, respectively, and tight junction proteins were examined by immunofluorescence. Intestinal barrier integrity was assessed by fluorescein isothiocyanate [FITC]-dextran assay.ResultsMultiple genes involved in cell commitment/proliferation and wound healing were differentially expressed in IBD compared with CTR. Among these, GATA6 was significantly decreased in the IBD epithelium compared with CTR. In mice, conditional deletion of GATA6 in the intestinal epithelium induced primarily epithelial damage, diminished zonula occludens-1 expression, and enhanced intestinal permeability, ultimately resulting in bacteria-driven local immune response and enhanced susceptibility to gut inflammation.ConclusionsReduced expression of GATA6 promotes intestinal barrier dysfunction, thus amplifying intestinal inflammatory pathology.

Background and AimsThe inflammatory bowel disease [IBD]-associated immune response is marked by excessive production of a variety of inflammatory cytokines, which are supposed to sustain and amplify the pathological process. OTUD5 is a deubiquitinating enzyme, which regulates cytokine production by both innate and adaptive immune cells. Here, we investigated the expression and role of OTUD5 in IBD.MethodsOTUD5 expression was evaluated in mucosal samples of patients with Crohn’s disease [CD], patients with ulcerative colitis [UC], and controls, as well as in mice with trinitrobenzene-sulphonic acid [TNBS]-induced colitis by real-time polymerase chain reaction, western blotting, immunohistochemistry, and immunofluorescence. Moreover, OTUD5 was assessed in lamina propria mononuclear cells [LPMC] stimulated with inflammatory cytokines. TNF-α, IL-6, and IL-10 were evaluated in LPMCs of IBD patients and in colitic mice transfected with a specific OTUD5 antisense oligonucleotide [AS].ResultsOTUD5 protein, but not RNA, expression was increased in inflamed ileal and colonic mucosal samples of patients with CD and patients with UC as compared with controls. In IBD, OTUD5-expressing cells were abundant in both epithelial and lamina propria compartments, and non-CD3+, HLA-DR+ LPMC were one of the major sources of the protein. OTUD5 expression was enhanced by IFN-γ through a p38/MAPK-dependent mechanism, and the AS-induced knockdown of OTUD5 in LPMCs of IBD patients and colitic mice reduced TNF-α.ConclusionsOur data show that OTUD5 is overexpressed in both CD and UC and suggest the involvement of such a protein in the amplification of the aberrant cytokine response in IBD.

Background & Aims The fragile X mental retardation protein (FMRP) affects multiple steps of the mRNA metabolism during brain development and in different neoplastic processes. However, the contribution of FMRP in colon carcinogenesis has not been investigated. Methods FMR1 mRNA transcript and FMRP protein expression were analyzed in human colon samples derived from patients with sporadic colorectal cancer (CRC) and healthy subjects. We used a well-established mouse model of sporadic CRC induced by azoxymethane to determine the possible role of FMRP in CRC. To address whether FMRP controls cancer cell survival, we analyzed cell death pathway in CRC human epithelial cell lines and in patient-derived colon cancer organoids in presence or absence of a specific FMR1 antisense oligonucleotide or siRNA. Results We document a significant increase of FMRP in human CRC relative to non-tumor tissues. Next, using an inducible mouse model of CRC, we observed a reduction of colonic tumor incidence and size in the Fmr1 knockout mice. The abrogation of FMRP induced spontaneous cell death in human CRC cell lines activating the necroptotic pathway. Indeed, specific immunoprecipitation experiments on human cell lines and CRC samples indicated that FMRP binds receptor-interacting protein kinase 1 (RIPK1) mRNA, suggesting that FMRP acts as a regulator of necroptosis pathway through the surveillance of RIPK1 mRNA metabolism. Treatment of human CRC cell lines and patient-derived colon cancer organoids with the FMR1 antisense resulted in up-regulation of RIPK1. Conclusions Altogether, these data support a role for FMRP in controlling RIPK1 expression and necroptotic activation in CRC., Graphical abstract

Background A recent phase III trial did not confirm the previous clinical and endoscopic improvements seen in patients with Crohn’s disease (CD) receiving Mongersen, an oral Smad7 antisense oligonucleotide. Factors accounting for such a discrepancy are unknown. Objective Our objective was to further assess whether Mongersen was effective as induction therapy in active CD and evaluate the in vitro inhibitory effect of various batches of Mongersen used in the previous and present trials on Smad7 expression. Methods In a phase II, open-label study, 18 patients with active CD (Crohn’s Disease Activity Index [CDAI] score > 220 and evidence of endoscopic lesions) received Mongersen 160 mg/day for 12 weeks. The rates of clinical remission, defined as CDAI < 150, and clinical response, defined as a CDAI score decrease ≥ 100, were evaluated at week 4, 8, and 12. The fraction of circulating CCR9-expressing leukocytes was assessed by flow cytometry. Smad7 expression was evaluated in the human colorectal cancer cell line HCT-116 transfected with different batches of Mongersen using real-time polymerase chain reaction (PCR) and Western blotting, Results The proportions of patients experiencing clinical remission were 38.9%, 55.6%, and 50.0% at week 4, 8, and 12, respectively. At the same time points, the rates of clinical response were 72.2%, 77.8%, and 77.8%, respectively. Mongersen reduced the percentages of CCR9-expressing CD45+ cells. The batch of Mongersen used in this study, but not two batches used in the phase III study, inhibited Smad7 expression in HCT-116 cells. Conclusions The present findings support the clinical benefit of Mongersen in active CD and show that various batches manufactured during the GED0301 program differ in their ability to inhibit in vitro Smad7. Trial Registration Number NCT02685683; EudraCT 2015-001693-18

The stromal compartment of colorectal cancer (CRC) is marked by the presence of large numbers of fibroblasts, termed cancer-associated fibroblasts (CAFs), which promote CRC growth and progression through the synthesis of various molecules targeting the neoplastic cells. Interleukin (IL)-34, a cytokine over-produced by CRC cells, stimulates CRC cell growth. Since IL-34 also regulates the function of inflammatory fibroblasts, we hypothesized that it could regulate the tumor promoting function of colorectal CAFs. By immunostaining and real-time PCR, we initially showed that IL-34 was highly produced by CAFs and to lesser extent by normal fibroblasts isolated from non-tumoral colonic mucosa of CRC patients. CAFs and normal fibroblasts expressed the functional receptors of IL-34. IL-34 induced normal fibroblasts to express &alpha, SMA, vimentin and fibroblast activation protein and enhanced fibroblast growth, thus generating a cellular phenotype resembling that of CAFs. Consistently, knockdown of IL-34 in CAFs with an antisense oligonucleotide (AS) decreased expression of such markers and inhibited cell proliferation. Co-culture of CRC cells with IL-34 AS-treated CAFs supernatants resulted in less cancer cell proliferation and migration. Among CAF-derived molecules known to promote CRC cell growth/migration, only netrin-1 and basic-fibroblast growth factor were induced by IL-34. Data suggest a role for IL-34 in the control of colorectal CAF function.

Tumors of the digestive system, when combined together, account for more new cases and deaths per year than tumors arising in any other system of the body and their incidence continues to increase. Despite major efforts aimed at discovering and validating novel and effective drugs against these malignancies, the process of developing such drugs remains lengthy and costly, with high attrition rates. Drug repositioning (also known as drug repurposing), that is, the process of finding new uses for approved drugs, has been gaining popularity in oncological drug development as it provides the opportunity to expedite promising anti-cancer agents into clinical trials. Among the drugs considered for repurposing in oncology, compounds belonging to some classes of anthelmintics—a group of agents acting against infections caused by parasitic worms (helminths) that colonize the mammalian intestine—have shown pronounced anti-tumor activities and attracted particular attention due to their ability to target key oncogenic signal transduction pathways. In this review, we summarize and discuss the available experimental and clinical evidence about the use of anthelmintic drugs for the treatment of cancers of the digestive system.

Colorectal cancer (CRC) is a major cause of cancer-related death in the world. Emerging evidence suggests that the clinical success of conventional chemotherapy does not merely rely on cell toxicity, but also results from the restoration of tumor immune surveillance. Anti-tumor immune response can be primed by immunogenic cell death (ICD), a form of apoptosis associated with endoplasmic reticulum stress (ERS) induction and the expression/release of specific damage-associated molecular patterns (DAMPs). Unfortunately, a limited number of ICD inducers have been identified so far. The anti-helmintic drug rafoxanide has recently showed anti-tumor activity in different cancer types, including CRC. As such latter effects relied on ERS activation, we here investigated whether rafoxanide could promote ICD of CRC cells. The potential of rafoxanide to induce ICD-related DAMPs in both human and mouse CRC cells was assessed by flow-cytometry, chemiluminescent assay and ELISA. In addition, the immunogenic potential of rafoxanide was assessed in vivo using a vaccination assay. Rafoxanide induced all the main DAMPs (ecto-calreticulin exposure, adenosine triphosphate (ATP)/high mobility group box 1 (HMGB1) release) required for ICD. We observed a marked increase of tumor-free survival among immunocompetent mice immunized with rafoxanide-treated dying tumor cells as compared with sham. Altogether, our data indicate rafoxanide as a bona fide ICD inducer.

Background & Aims: Food additives, such as emulsifiers, stabilizers, or bulking agents, are present in the Western diet and their consumption is increasing. However, little is known about their potential effects on intestinal homeostasis. In this study we examined the effect of some of these food additives on gut inflammation. Methods: Mice were given drinking water containing maltodextrin (MDX), propylene glycol, or animal gelatin, and then challenged with dextran sulfate sodium or indomethacin. In parallel, mice fed a MDX-enriched diet were given the endoplasmic reticulum (ER) stress inhibitor tauroursodeoxycholic acid (TUDCA). Transcriptomic analysis, real-time polymerase chain reaction, mucin-2 expression, phosphorylated p38 mitogen-activated protein (MAP) kinase quantification, and H&E staining was performed on colonic tissues. Mucosa-associated microbiota composition was characterized by 16S ribosomal RNA sequencing. For the in vitro experiments, murine intestinal crypts and the human mucus-secreting HT29-methotrexate treated cell line were stimulated with MDX in the presence or absence of TUDCA or a p38 MAP kinase inhibitor. Results: Diets enriched in MDX, but not propylene glycol or animal gelatin, exacerbated intestinal inflammation in both models. Analysis of the mechanisms underlying the detrimental effect of MDX showed up-regulation of inositol requiring protein 1β, a sensor of ER stress, in goblet cells, and a reduction of mucin-2 expression with no significant change in mucosa-associated microbiota. Stimulation of murine intestinal crypts and HT29-methotrexate treated cell line cells with MDX induced inositol requiring protein 1β via a p38 MAP kinase–dependent mechanism. Treatment of mice with TUDCA prevented mucin-2 depletion and attenuated colitis in MDX-fed mice. Conclusions: MDX increases ER stress in gut epithelial cells with the downstream effect of reducing mucus production and enhancing colitis susceptibility. Keywords: Colitis, IBD, Unfolded Protein Response, Intestinal Epithelium

Metformin, a hypoglycemic drug used for treatment of type 2 diabetes, regulates inflammatory pathways. By using several models of intestinal inflammation, we examined whether metformin exerts anti-inflammatory effects and investigated the basic mechanism by which metformin blocks pathologic signals. Colitic mice given metformin exhibited less colonic inflammation and increased expression of active AMP-activated protein kinase, a mediator of the metabolic effects of metformin, in both epithelial and lamina propria compartments. Pharmacological inhibition of AMP-activated protein kinase reduced but did not prevent metformin-induced therapeutic effect as well as treatment of colitic mice with a pharmacological activator of AMP-activated protein kinase attenuated but did not resolve colitis. These data suggest that the anti-inflammatory effect of metformin relies on the control of additional pathways other than AMP-activated protein kinase. Indeed, metformin down-regulated p38 MAP kinase activation in colitic mice through an AMP-activated protein kinase-independent mechanism. Expression of active form of AMP-activated protein kinase was reduced in inflammatory bowel disease patients and treatment of mucosal cells of such patients with metformin enhanced AMP-activated protein kinase activation and reduced p38 MAP kinase activation, thereby inhibiting interleukin-6 expression. Our findings indicate that metformin is a good candidate for inhibiting pathological inflammation in the gut.

Pseudomonas aeruginosa is the major microorganism colonizing the respiratory epithelium in cystic fibrosis (CF) sufferers. The widespread use of available antibiotics has drastically reduced their efficacy, and antimicrobial peptides (AMPs) are a promising alternative. Among them, the frog skin-derived AMPs, i.e., Esc(1-21) and its diastereomer, Esc(1-21)-1c, have recently shown potent activity against free-living and sessile forms of P. aeruginosa . Importantly, this pathogen also escapes antibiotics treatment by invading airway epithelial cells. Here, we demonstrate that both AMPs kill Pseudomonas once internalized into bronchial cells which express either the functional or the ΔF508 mutant of the CF transmembrane conductance regulator. A higher efficacy is displayed by Esc(1-21)-1c (90% killing at 15 μM in 1 h). We also show the peptides' ability to stimulate migration of these cells and restore the induction of cell migration that is inhibited by Pseudomonas lipopolysaccharide when used at concentrations mimicking lung infection. This property of AMPs was not investigated before. Our findings suggest new therapeutics that not only eliminate bacteria but also can promote reepithelialization of the injured infected tissue. Confocal microscopy indicated that both peptides are intracellularly localized with a different distribution. Biochemical analyses highlighted that Esc(1-21)-1c is significantly more resistant than the all- l peptide to bacterial and human elastase, which is abundant in CF lungs. Besides proposing a plausible mechanism underlying the properties of the two AMPs, we discuss the data with regard to differences between them and suggest Esc(1-21)-1c as a candidate for the development of a new multifunctional drug against Pseudomonas respiratory infections.

Background and aims In ulcerative colitis [UC], mucosal damage occurs in areas that are infiltrated with neutrophils. The antimicrobial function of neutrophils relies in part on the formation of extracellular web-like structures, named neutrophil extracellular traps [NETs]. The formation and/or clearance of aberrant NETs have been associated with several immune diseases. Here we investigated the role of NETs in UC-related inflammation. Methods The expression of NET-associated proteins was evaluated in colonic biopsies of patients with Crohn's disease [CD], UC and in normal controls [NC] by Western blotting, immunofluorescence and immunohistochemistry. Colonic biopsies of UC patients were analysed before and after anti-tumour necrosis factor α [anti-TNF-α] treatment. The capacity of neutrophils to produce NETs upon activation was tested in vitro. UC lamina propria mononuclear cells [LPMCs] were cultured with NETs in the presence or absence of an extracellular signal-regulated kinase-1/2 [ERK1/2] inhibitor and inflammatory cytokine induction was assessed by real-time polymerase chain reaction and enzyme-linked immunosorbent assay. We also characterized the contribution of NETs in dextran sodium sulfate [DSS]-induced colitis. Results NET-associated proteins were over-expressed in inflamed colon of UC patients as compared to CD patients and NC. Circulating neutrophils of UC patients produced NETs in response to TNF-α stimulation, and reduced expression of NET-related proteins and diminished NET formation were seen in patients receiving successful treatment with anti-TNF-α. Treatment of UC LPMCs with NETs activated ERK1/2, thus enhancing TNF-α and interleukin-1β [IL-1β] production. NETs were induced in mice with DSS-colitis and in vivo inhibition of NET release attenuated colitis. Conclusions Our data show that NET release occurs in UC and suggest a role for NETs in sustaining mucosal inflammation in this disorder.

Aryl hydrocarbon receptor (AhR), a transcription factor activated by a large number of natural and synthetic agents, modulates the activity of immune cells in the gut and represents an important link between the environment and immune-mediated pathologies. In this study, we investigated the role of AhR in celiac disease (CD), a gluten-driven enteropathy. AhR expression was evaluated in intestinal biopsies taken from patients with CD and controls by real-time polymerase chain reaction (PCR), immunohistochemistry and flow cytometry. AhR was also analyzed in ex vivo organ cultures of duodenal biopsies taken from inactive CD patients incubated in presence or absence of peptic-tryptic digest of gliadin. IFN-γ, TNF-α, granzyme B, and perforin expression was evaluated in anti-CD3/CD28-activated intestinal lamina propria mononuclear cells (LPMC) and intestinal intra-epithelial cells (IEL) of active CD patients cultured in the presence or absence of the AhR agonist 6-formylindolo(3, 2-b)carbazole (Ficz). Finally, the protective role of AhR was evaluated in a mouse model of poly I:C-driven small intestine damage. AhR RNA transcripts were reduced in active CD samples as compared to inactive CD and normal controls. Flow cytometry confirmed such results and showed a reduction of AhR in both IEL and LPMC of active CD patients. The addition of a peptic-tryptic digest of gliadin to ex vivo organ cultures of duodenal biopsies taken from inactive CD patients reduced AhR expression. Treatment of CD IEL and LPMC with Ficz reduced the levels of inflammatory cytokines, granzyme B and perforin. Mice injected with Ficz were protected against poly I:C-induced intestinal lesions. Our findings suggest that defective AhR-driven signals could contribute to amplify pathogenic responses in the gut of CD patients.

Colorectal cancer (CRC) remains one of the leading causes of mortality worldwide. Drug repositioning is a promising approach for new cancer therapies, as it provides the opportunity to rapidly advance potentially promising agents into clinical trials. The FDA-approved anti-helminthic drug rafoxanide was recently reported to antagonize the oncogenic function of the BRAF V600E mutant protein, commonly found in CRCs, as well as to inhibit the proliferation of skin cancer cells. These observations prompted us to investigate the potential anti-cancer effects of rafoxanide in CRC models. We found rafoxanide inhibited proliferation in CRC cells, but not in normal colonic epithelial cells. Rafoxanide's anti-proliferative action was associated with marked reduction in cyclin D1 protein levels and accumulation of cells in the G0/G1 phase. These effects relied on selective induction of the endoplasmic reticulum stress (ERS) response in CRC cells and were followed by caspase-dependent cell death. Systemic administration of rafoxanide to Apcmin/+ mice induced to develop CRCs caused ERS activation, proliferation inhibition and apoptosis induction in the neoplastic cells. Collectively, our data suggest rafoxanide might be repurposed as an anti-cancer drug for the treatment of CRC.

In this study we designed and synthesized a new library of antimicrobial peptides correlated to [Pro3,DLeu9]TL 1, a temporin L derivative devoid of cytolytic effects in vitro, and investigated the correlation between the α-helical content of the compounds and their antibacterial, cytotoxic and hemolytic activities. We systematically replaced Gly in position 10 of reference peptide with several amino acids. Structure-activity relationship studies of these analogues were performed by means of antimicrobial and cytotoxicity assays along with CD spectroscopy analyses. NMR analysis was also accomplished for compound 10. As well, the most promising peptides were additionally evaluated for their activity against some clinical strains isolated from human skin and for their mechanism of action by studying the kinetics of membrane perturbation of some representative microbial strains. We identified novel analogues with interesting properties that make them attractive lead compounds for potential topical applications.

Interleukin-34 (IL-34), a cytokine produced by a wide range of cells, binds to the macrophage colony-stimulating factor receptor (M-CSFR-1) and receptor-type protein-tyrosine phosphatase zeta (PTP-z) and controls myeloid cell differentiation, proliferation and survival. various types of cancers over-express IL-34 but the role of the cytokine in colorectal cancer (CRC) remains unknown. We here investigated the expression and functional role of IL-34 in CRC. A more pronounced expression of IL-34 was seen in CRC samples as compared to matched normal/benign colonic samples and this occurred at both RNA and protein level. Immunohistochemical analysis of CRC tissue samples showed that both cancer cells and lamina propria mononuclear cells over-expressed IL-34. Additionally, CRC cells expressed both M-CSFR-1 and PTP-z, thus suggesting that CRC cells can be responsive to IL-34. Indeed, stimulation of DLD-1 cancer cells with IL-34, but not with MSCF1, enhanced the cell proliferation and cell invasion without affecting cell survival. Analysis of intracellular signals underlying the mitogenic effect of IL-34 revealed that the cytokine enhanced activation of ERK1/2 and pharmacologic inhibition of ERK1/2 abrogated IL-34-driven cell proliferation. Consistently, IL-34 knockdown in HT-29 cells with a specific IL-34 antisense oligonucleotide reduced ERK1/2 activation, cell proliferation and enhanced the susceptibility of cells to Oxaliplatin-induced death. This is the first study showing up-regulation of IL-34 in CRC and suggesting a role for this cytokine in colon tumorigenesis.

Aims Compartmentalization of cAMP and PKA activity in cardiac muscle cells plays a key role in maintaining basal and enhanced contractility stimulated by sympathetic nerve activity. In cardiomyocytes, activation of adrenergic receptor increases cAMP production, which is countered by the hydrolytic activity of selective phosphodiesterases (PDEs). The intracellular regional dynamics of cAMP production and hydrolysis modulate downstream signals resulting in different biological responses. The interplay between beta receptors (βARs) signalling and phosphodiesterase 5 (PDE5) activity remains to be addressed. Methods and results Using combined strategies with pharmacological inhibitors and genetic deletion of PDEs and βAR isoforms, we revealed a specific pool of cAMP that is under dual regulation by PDE2 and, indirectly, PDE5 activity. Inhibition of PDE5 with sildenafil produces a cGMP-dependent activation of PDE2 that attenuates cAMP generation induced by βAR agonists, with concomitant modulation of stimulated contraction rate and calcium transients. PDE2 haploinsufficiency abolished the effects of sildenafil. The negative chronotropic effect of PDE5 inhibition through PDE2 activation was also observed in sinoatrial node tissue from adult mice. PDE5 inhibition selectively lowered contraction rate stimulated by β2AR, but not β1AR activation, supporting a compartmentalization of the cGMP-modulated pool of cAMP. Conclusion These data identify a new effect of PDE5 inhibitors on the modulation of cardiomyocyte response to adrenergic stimulation via PDE5–PDE2-mediated cross-talk.

The growing number of microbial pathogens resistant to available antibiotics is a serious threat to human life. Among them is the bacterium Staphylococcus aureus , which colonizes keratinocytes, the most abundant cell type in the epidermis. Its intracellular accumulation complicates treatments against resulting infections, mainly due to the limited diffusion of conventional drugs into the cells. Temporins A (Ta) and B (Tb) are short frog skin antimicrobial peptides (AMPs). Despite extensive studies regarding their antimicrobial activity, very little is known about their activity on infected cells or involvement in various immunomodulatory functions. Here we show that Tb kills both ATCC-derived and multidrug-resistant clinical isolates of S. aureus within infected HaCaT keratinocytes (80% and 40% bacterial mortality, respectively) at a nontoxic concentration, i.e., 16 μM, whereas a weaker effect is displayed by Ta. Furthermore, the peptides prevent killing of keratinocytes by the invading bacteria. Further studies revealed that both temporins promote wound healing in a monolayer of HaCaT cells, with front speed migrations of 19 μm/h and 12 μm/h for Ta and Tb, respectively. Migration is inhibited by mitomycin C and involves the epidermal growth factor receptor (EGFR) signaling pathway. Finally, confocal fluorescence microscopy indicated that the peptides diffuse into the cells. By combining antibacterial and wound-healing activities, Ta and Tb may act as multifunctional mediators of innate immunity in humans. Particularly, their nonendogenous origin may reduce microbial resistance to them as well as the risk of autoimmune diseases in mammals.

Previous investigations indicate that alpha-melanocyte-stimulating hormone (alpha-MSH) and certain synthetic analogues of it exert antimicrobial effects against bacteria and yeasts. However, these molecules have weak activity in standard microbiology conditions and this hampers a realistic clinical use. The aim in the present study was to identify novel peptides with broad-spectrum antimicrobial activity in growth medium. To this purpose, the Gly10 residue in the [DNal(2')-7,Phe-12]-MSH(6-13) sequence was replaced with conventional and unconventional amino acids with different degrees of conformational rigidity. Two derivatives in which Gly10 was replaced by the residues Aic and Cha, respectively, had substantial activity against Candida strains, including C. albicans, C. glabrata, and C. krusei and against gram-positive and gram-negative bacteria. Conformational analysis indicated that the helical structure along residues 8-13 is a key factor in antimicrobial activity. Synthetic analogues of alpha-MSH can be valuable agents to treat infections in humans. The structural preferences associated with antimicrobial activity identified in this research can help further development of synthetic melanocortins with enhanced biological activity.

The extensive search for alternative therapeutics against microbial pathogens has led to the discovery of cationic peptides as new anti-infectives with a novel mode of action. Particular interest has been devoted to small linear peptides that can be efficiently made by chemical synthesis at competitive costs. The most promising originate from a large family of short, naturally occurring peptides found in the skin of amphibia of Rana genus, i.e. the temporins. This review is mainly focused on the recent structure-function studies of the earliest known temporin isoforms (TA, TB and TL) and their potential clinical role as novel antimicrobial agents. The development of novel antibiotics is an urgent public health concern due to the increased resistance of microorganisms to conventional antibiotics, particularly in the hospital setting.