Epithelial Hyperproliferation Research Articles

PREVAX: A Phase I Clinical Trial of an EGF-Based Vaccine in Moderate-to-Severe COPD Patients.

EGFR has been suggested to contribute to COPD development and progression. Excessive ligand activation of the receptor leads to epithelial hyperproliferation and increased production of mucus, together with alterations in the primary cilia. The present study was designed to evaluate the safety and effect of depleting EGF in moderate-to-severe COPD patients, with an EGF-based vaccine. A phase I trial was conducted in subjects with moderate or severe COPD. The anti-EGF vaccine schedule consisted of 4 biweekly doses followed by 4 monthly boosters. The primary endpoint was the evaluation of the safety and immunogenicity of the vaccine, together with the change in FEV1 and physical function at week 24. Twenty-six patients with moderate or severe COPD were included in the trial. The vaccine was well tolerated and no serious related adverse events were reported. Ninety percent of the individuals developed a protective antibody response. The specific anti-EGF antibodies had high avidity and were able to inhibit EGFR phosphorylation. At the end of vaccination, serum EGF became undetectable. At week 24, there was a clinically significant improvement in lung function, with a mean change in trough FEV1 of 106 mL. Patients also increased their physical functioning. The EGF-based vaccine was immunogenic and provoked an EGF exhaustion in patients with moderate-to-severe COPD. Depleting EGF might result in a meaningful increase in FEV1, with good tolerability. The current results provide new avenues to treat chronic inflammatory lung diseases associated with EGFR aberrant signaling.

Colonocyte keratins stabilize mitochondria and contribute to mitochondrial energy metabolism.

Keratin intermediate filaments form dynamic filamentous networks, which provide mechanical stability, scaffolding, and protection against stress to epithelial cells. Keratins and other intermediate filaments have been increasingly linked to the regulation of mitochondrial function and homeostasis in different tissues and cell types. While deletion of keratin 8 (K8-/-) in mouse colon elicits a colitis-like phenotype, epithelial hyperproliferation, and blunted mitochondrial ketogenesis, the role of K8 in colonocyte mitochondrial function and energy metabolism is unknown. We used two K8 knockout mouse models and CRISPR/Cas9 K8-/- colorectal adenocarcinoma Caco-2 cells to answer this question. The results show that K8-/- colonocyte mitochondria in vivo are smaller and rounder and that mitochondrial motility is increased in K8-/- Caco-2 cells. Furthermore, K8-/- Caco-2 cells displayed diminished mitochondrial respiration and decreased mitochondrial membrane potential compared with controls, whereas glycolysis was not affected. The levels of mitochondrial respiratory chain complex proteins and mitochondrial regulatory proteins mitofusin-2 and prohibitin were decreased both in vitro in K8-/- Caco-2 cells and in vivo in K8-/- mouse colonocytes, and reexpression of K8 into K8-/- Caco-2 cells normalizes the mitofusin-2 levels. Mitochondrial Ca2+ is an important regulator of mitochondrial energy metabolism and homeostasis, and Caco-2 cells lacking K8 displayed decreased levels and altered dynamics of mitochondrial matrix and cytoplasmic Ca2+. In summary, these novel findings attribute an important role for colonocyte K8 in stabilizing mitochondrial shape and movement and maintaining mitochondrial respiration and Ca2+ signaling. Further, how these metabolically compromised colonocytes are capable of hyperproliferating presents an intriguing question for future studies.NEW & NOTEWORTHY In this study, we show that colonocyte intermediate filament protein keratin 8 is important for stabilizing mitochondria and maintaining mitochondrial energy metabolism, as keratin 8-deficient colonocytes display smaller, rounder, and more motile mitochondria, diminished mitochondrial respiration, and altered Ca2+ dynamics. Changes in fusion-regulating proteins are rescued with reexpression of keratin 8. These alterations in colonocyte mitochondrial homeostasis contribute to keratin 8-associated colitis pathophysiology.

The role of S100A8 and S100A9 in external auditory canal cholesteatoma.

Studies indicated that diverse cellular mechanisms including epithelial migration and hyper-proliferation, inflammatory responses, and enzymatic bone erosion were involved in the pathogenesis of cholesteatoma. S100A8 and S100A9, which are Ca2+-binding proteins belonging to the S100 family, can trigger the signaling pathways involved in the inflammatory processes, and a variety of cellular processes includes cell cycle progression, proliferation, and cell migration. However, the role of S100A8 and S100A9 and their associated inflammation and other signaling pathways in cholesteatoma have not been investigated yet. This study aimed to investigate the role of S100A8 and S100A9 in external auditory canal cholesteatoma and their potential pathological mechanisms. The study conducted histological staining, immunostaining, PCR, and Western blot to investigate the expression of S100A8/A9 and its related pathways in clinic EACC and the murine model of EACC. Our data showed that there were increased mRNA and protein levels of S100A8 and S100A9 in clinical and animal models of EACC and the S100A8/A9 heterodimer protein was increased in the EACC model. Our study further demonstrated that the increased S100A8 and S100A9 were associated with apoptosis as well as inflammatory (TGF-β, IFN-γ, and IL-10) and angiogenetic (VEGF, HGF/SF, and c-Met) molecular pathways. The correlation analysis indicated that S100A8 and S100A9 were correlated with clinic staging, apoptosis, and inflammatory and angiogenetic factors. This study provided novel insight into the role of S100A8 and S100A9 associated with pathological mechanisms of EACC.

Acetaldehyde and defective mismatch repair increase colonic tumours in a Lynch syndrome model with Aldh1b1 inactivation.

ALDH1B1 expressed in the intestinal epithelium metabolises acetaldehyde to acetate, protecting against acetaldehyde-induced DNA damage. MSH2 is a key component of the DNA mismatch repair (MMR) pathway involved in Lynch syndrome (LS)-associated colorectal cancers. Here, we show that defective MMR (dMMR) interacts with acetaldehyde, in a gene/environment interaction, enhancing dMMR-driven colonic tumour formation in a LS murine model of Msh2 conditional inactivation (Lgr5-CreER; Msh2flox/-, or Msh2-LS) combined with Aldh1b1 inactivation. Conditional (Aldh1b1flox/flox) or constitutive (Aldh1b1-/-) Aldh1b1 knockout alleles combined with the conditional Msh2flox/- intestinal knockout mouse model of LS (Msh2-LS) received either ethanol, which is metabolised to acetaldehyde, or water. We demonstrated that 41.7% of ethanol-treated Aldh1b1flox/flox Msh2-LS mice and 66.7% of Aldh1b1-/- Msh2-LS mice developed colonic epithelial hyperproliferation and adenoma formation, in 4.5 and 6 months, respectively, significantly greater than 0% in water-treated control mice. Significantly higher numbers of dMMR colonic crypt foci precursors and increased plasma acetaldehyde levels were observed in ethanol-treated Aldh1b1flox/flox Msh2-LS and Aldh1b1-/- Msh2-LS mice compared with those in water-treated controls. Hence, ALDH1B1 loss increases acetaldehyde levels and DNA damage that interacts with dMMR to accelerate colonic, but not small intestinal, tumour formation.

Study of dietary‑induced progression of psoriasis‑like mice based on gut macrophage polarization.

The aim of the present study was to investigate the influence of stimulating food (SF), a Traditional Chinese Medicine term for a high protein, high fat diet, on psoriasis exacerbation. It was hypothesized that SF disposed psoriasis-like aggravation might be related to inflammatory pathways induction via gut dysbiosis. In the present study, mice were fed either an SF or normal diet for 4 weeks. In the last week, their back hair was removed to establish psoriasis-like dermatitis by imiquimod. After sacrifice, blood samples, alimentary tissues and skin lesions were collected and tested by enzyme-linked immunosorbent assay, western blotting, immunohistochemistry and immunofluorescence. Compared with normal diet groups, body weight and blood glucose of SF diet mice were not increased, but they exhibited higher modified Psoriasis Area and Severity Index scores and corresponding epithelial hyperproliferation. Unexpectedly, skin lesions showed abnormal lower protein expressions of Notch and TLR-2/NF-κB p65 signaling pathway, which was attributable to severe skin damage. No difference was observed in the structure and inflammatory cell infiltration of the gut between groups. Instead, macrophage polarization (M1/M2) in the gut of the SF diet group marked by high expression of CD11b (a marker of macrophage, M1) and mild low expression of MRC1 (a marker of macrophage, M2), which resulted in increased TNF-α, decreased IL-10, IL-35, and unchanged IL-17 in serum. Furthermore, serum derived from SF diet mice promoted translocation of NF-κB p65 in HaCaT cells, which indirectly suggested a systemic inflammation. These results suggested that mice fed a continuous SF diet for a time could change gut macrophage polarization, which secretes proinflammatory cytokines into blood circulation. Once transported to skin lesions, these cytokines activate psoriasis tissue resident immune cells and present as psoriasis exacerbation.

Loss of bone morphogenetic protein signaling in fibroblasts results in CXCL12-driven serrated polyp development

Mutations in Bone Morphogenetic Protein (BMP) Receptor (BMPR)1A and SMAD4 are detected in 50% of juvenile polyposis syndrome (JPS) patients, who develop stroma-rich hamartomatous polyps. The established role of stromal cells in regulating BMP activity in the intestine implies a role for stromal cells in polyp development. We used conditional Cre-LoxP mice to investigate how specific loss of BMPR1A in endothelial cells, fibroblasts, or myofibroblasts/smooth muscle cells affects intestinal homeostasis. Selective loss of BMPR1A in fibroblasts causes severe histological changes in the intestines with a significant increase in stromal cell content and epithelial cell hyperproliferation, leading to numerous serrated polyps. This phenotype suggests that crucial changes occur in the fibroblast secretome that influences polyp development. Analyses of publicly available RNA expression databases identified CXCL12 as a potential candidate. RNAscope in situ hybridization showed an evident increase of Cxcl12-expressing fibroblasts. In vitro, stimulation of fibroblasts with BMPs resulted in downregulation of CXCL12, while inhibition of the BMP pathway resulted in gradual upregulation of CXCL12 over time. Moreover, neutralization of CXCL12 in vivo in the fibroblast-specific BMPR1A KO mice resulted in a significant decrease in polyp formation. Finally, in CRC patient specimens, mRNA-expression data showed that patients with high GREMLIN1 and CXCL12 expression had a significantly poorer overall survival. Significantly higher GREMLIN1, NOGGIN, and CXCL12 expression were detected in the Consensus Molecular Subtype 4 (CMS4) colorectal cancers, which are thought to arise from serrated polyps. Taken together, these data imply that fibroblast-specific BMP signaling–CXCL12 interaction could have a role in the etiology of serrated polyp formation.

KDF1 Novel Variant Causes Unique Dental and Oral Epithelial Defects.

Keratinocyte differentiation factor 1 (KDF1) is a recently identified and rare candidate gene for human tooth agenesis; however, KDF1-related morphological characteristics and pathological changes in dental tissue and the oral epithelium remain largely unknown. Here, we employed whole-exome sequencing (WES) and Sanger sequencing to screen for the suspected variants in a cohort of 151 tooth agenesis patients, and we segregated a novel KDF1 heterozygous missense variation, c.920G>C (p.R307P), in a non-syndromic tooth agenesis family. Essential bioinformatics analyses and tertiary structural predictions were performed to analyze the structural changes and functional impacts of the novel KDF1 variant. The subsequent functional assessment using a TOP-flash/FOP-flash luciferase reporter system demonstrated that KDF1 variants suppressed the activation of canonical Wnt signaling in 293T cells. To comprehensively investigate the KDF1-related oral morphological anomalies, we performed scanning electron microscopy and ground section of the lower right lateral deciduous incisor extracted from #285 proband, and histopathological assessment of the gingiva. The phenotypic analyses revealed a series of tooth morphological anomalies related to the KDF1 variant R307P, including a shovel-shaped lingual surface of incisors and cornicione-shaped marginal ridges with anomalous morphological occlusal grooves of premolars and molars. Notably, keratinized gingival epithelium abnormalities were revealed in the proband and characterized by epithelial dyskeratosis with residual nuclei, indistinct stratum granulosum, epithelial hyperproliferation, and impaired epithelial differentiation. Our findings revealed new developmental anomalies in the tooth and gingival epithelium of a non-syndromic tooth agenesis individual with a novel pathogenic KDF1 variant, broadening the phenotypic spectrum of KDF1-related disorders and providing new evidence for the crucial role of KDF1 in regulating human dental and oral epithelial development.

Vitamin D receptor and STAT6 interactome governs oesophageal epithelial barrier responses to IL-13 signalling

ObjectiveThe contribution of vitamin D (VD) deficiency to the pathogenesis of allergic diseases remains elusive. We aimed to define the impact of VD on oesophageal allergic inflammation.DesignWe assessed the genomic...

Investigation of EGF, IL1-α and IL-6 levels and selected hematological parameters (NLR, MPV) in patients with the chronic cholesteatomatous otitis media.

In this study we aimed to investigate epidermal growth factor (EGF), interleukin (IL1)-α and IL-6 levels, and hematological parameters in the serum samples of patients with chronic cholesteatomatous otitis media (CCOM). This prospective included 40 patients who underwent surgery due to CCOM between June 2020 and May 2021. The stage of middle ear cholesteatoma was determined on each chart using the EAONO/JOS system. The control group comprised of 30 adults who were scheduled for septoplasty over the same period in our hospital, had no otological complaints, and had normal otological findings. The demographic, clinical, and laboratory data of the patients were obtained from the electronic medical record system of our hospital. The serum EGF, IL1-α and IL-6 levels, and hematological parameters (neutrophil-lymphocyte ratio (NLR) and mean platelet volume (MPV)) were compared between the CCOM and control groups. Seven patients had Stage 1 and 33 patients had Stage 2 middle ear cholestatoma. There was no statistically significant difference between the CCOM and control groups in terms of age and gender (p=0.092 and p=0.616, respectively). The serum EGF and IL1-α levels of the CCOM group were statistically significantly higher than those of the control group (p=0.047 and p=0.013, respectively). No statistically significant difference was observed in the serum IL-6 levels of the CCOM and control groups (p=0.675). There was also no significant difference between the CCOM and control groups in terms of the mean NLR and MPV values ​​(p=0.887 and p=0.164, respectively). There was no significant difference between the Stage 1 and Stage 2 cholesteatoma subgroups in terms of the mean EGF, IL1-α, IL-6 levels (p=0.204, p=0.557 and p=0.613, respectively), and the mean NLR and MPV values (p=0.487, p=0.439, respectively). Increased serum EGF and IL1-α levels in patients with CCOM suggest that these cytokines may play a role in cholesteatomatous epithelial hyperproliferation.

C-X-C motif chemokine ligand 1 induced by Hedgehog signaling promotes mouse extrahepatic bile duct repair after acute injury.

In extrahepatic bile duct (EHBD) cholangiopathies, including primary sclerosing cholangitis, a reactive cholangiocyte phenotype is associated with inflammation and epithelial hyperproliferation. The signaling pathways involved in EHBD injury response are poorly understood. In this study, we investigated the role of Hedgehog (HH) signaling and its downstream effectors in controlling biliary proliferation and inflammation after EHBD injury. Using mouse bile duct ligation as an acute EHBD injury model, we used inhibitory paradigms to uncover mechanisms promoting the proliferative response. HH signaling was inhibited genetically in Gli1-/- mice or by treating wild-type mice with LDE225. The role of neutrophils was tested using chemical (SB225002) and biological (lymphocyte antigen 6 complex locus G6D [Ly6G] antibodies) inhibitors of neutrophil recruitment. The cellular response was defined through morphometric quantification of proliferating cells and CD45+ and Ly6G+ immune cell populations. Key signaling component expression was measured and localized to specific EHBD cellular compartments by in situ hybridization, reporter strain analysis, and immunohistochemistry. Epithelial cell proliferation peaked 24 h after EHBD injury, preceded stromal cell proliferation, and was associated with neutrophil influx. Indian HH ligand expression in the biliary epithelium rapidly increased after injury. HH-responding cells and neutrophil chemoattractant C-X-C motif chemokine ligand 1 (CXCL1) expression mapped to EHBD stromal cells. Inhibition of HH signaling blocked CXCL1 induction, diminishing neutrophil recruitment and the biliary proliferative response to injury. Directly targeting neutrophils by inhibition of the CXCL1/C-X-C motif chemokine receptor 2/Ly6G signaling axis also decreased biliary proliferation. HH-regulated CXCL1 orchestrates the early inflammatory response and biliary proliferation after EHBD injury through complex cellular crosstalk.

Microneedle and iontophoresis mediated delivery of methotrexate into and across healthy and psoriatic skin

Psoriasis is a condition of the skin which involves scales, dry patches, and inflammation. Methotrexate (logP: −1.8, MW:454.44 g/mol) is administered orally or intravenously to treat psoriasis. The first-pass metabolism and systemic toxicity can be avoided by administration via skin. Topical and transdermal delivery of methotrexate using iontophoresis and microneedles, alone and in combination was investigated using full-thickness healthy human skin. It is also equally relevant to evaluate the delivery into and across damaged/diseased skin. Hence, this study investigated the delivery of methotrexate using ex vivo healthy and psoriatic human skin to understand the effect of skin disease condition on delivery of methotrexate via skin. A lower resistance and a higher TEWL for psoriatic skin indicated damaged barrier function, while histology studies indicated epithelial hyperproliferation and elongated rete ridges. Using the optimized iontophoretic parameters, there was no significant difference in receptor delivery for psoriatic skin (39.51 ± 4.45 µg/sq.cm) as compared to healthy skin (43.15 ± 0.83 µg/sq.cm). However, methotrexate delivery into psoriatic skin (126.23 ± 24.65 µg/sq.cm) was significantly higher as compared to healthy skin (12.02 ± 4.89 µg/sq.cm). Thus, significantly higher total delivery was observed from psoriatic skin than healthy skin.

DOP51 Loss of PTPN23 in the intestinal epithelium results in epithelial hyperproliferation and lethal diarrhea in a microbiota dependent manner

Abstract Background Protein tyrosine phosphtase non-receptor type 23 (PTPN23) plays a critical role in regulating epidermal growth factor (EGF) receptor signaling and its loss has been associated with aberrant cell proliferation and promotes onset of epithelial cancers. However, the role of PTPN23 in the intestinal epithelium has not been investigated yet. Here, we investigated how PTPN23 deletion in intestinal epithelial cells (IEC) affects intestinal homeostasis. Methods To study the role of PTPN23 in the intestinal epithelium, we crossed mice with a LoxP flanked PTPN23 gene (PTPN23fl/fl mice) to mice expressing the CreERT construct under the villin promoter (PTPN23-VilCreERT mice). PTPN23 was deleted in IEC in these mice by tamoxifen-injections on five consecutive days. PTPN23 fl/fl mice injected with tamoxifen served as control. Results PTPN23 deletion in IEC resulted in drastic loss of weight starting around 10-14days after the first tamoxifen injection, eventually leading to death within 3–5 weeks due to severe wasting disease with severe diarrhea. Histology revealed massive hyper-proliferation of the colonic epithelium accompanied with elevated immune cell infiltration. In line with previous reports on the function of PTPN23, we observed highly elevated levels of EGF receptor, possibly accounting for the massive epithelial hyper-proliferation and aberrant water secretion/defective water resorption in these mice. Furthermore, we observed bacterial translocation to the spleen and the liver, indicating defective anti-bacterial defense in the intestinal epithelium of PTPN23-VilCreERT mice. In line with this, 16S sequencing revealed significant differences in the intestinal microbiome with an overgrowth of bacteria that have been reported to be heavily coated with IgA. PTPN23-VilCreERT mice showed reduced apical presence of the poly Ig receptor, a receptor that transports IgA from the lamina propria through IEC into the gut lumen. Notably, while serum IgA levels were normal, its levels in the stool were reduced, confirming defective transport of IgA into the gut lumen. In addition, autophagy was significantly reduced in PTPN23-VilCreERT mice when compared to their littermates. Of interest, antibiotic treatment was sufficient to prevent epithelial hyper-proliferation, diarrhea and death in PTPN23VilCreERT mice, indicating that this drastic phenotype was microbiota-dependent and likely the result of defects in bacterial handling. Conclusion Our results demonstrate that PTPN23 is indispensible for normal IEC function and its loss renders the intestinal epithelium unable to cope with invading bacteria. This uncovers a novel, so far unknown role of PTPN23 for regulating pathways involved in bacterial handling.

Elevated Protein Kinase A Activity in Stomach Mesenchyme Disrupts Mesenchymal-epithelial Crosstalk and Induces Preneoplasia.

Background & AimsMesenchymal-epithelial crosstalk (MEC) in the stomach is executed by pathways such as bone morphogenetic protein (BMP) and extracellular signal-regulated kinase (ERK). Mis-regulation of MEC disrupts gastric homeostasis and causes tumorigenesis. Protein Kinase A (PKA) crosstalks with BMP and ERK signaling; however, PKA function(s) in stomach development and homeostasis remains undefined.MethodsWe generated a novel Six2-Cre+/-PKAcαRfl/wt (CA-PKA) mouse in which expression of constitutive-active PKAcαR was induced in gastric mesenchyme progenitors. Lineage tracing determined spatiotemporal activity of Six2-Cre in the stomach. For phenotyping CA-PKA mice histological, co-immunofluorescence, immunoblotting, mRNA sequencing, and bioinformatics analyses were performed.ResultsLineage tracing showed that Six2-Cre activity in the stomach is restricted to the mesenchymal compartment. CA-PKA mice showed disruption of gastric homeostasis characterized by aberrant mucosal development and epithelial hyperproliferation; ultimately developing multiple features of gastric corpus preneoplasia including decreased parietal cells, mucous cell hyperplasia, spasmolytic peptide expressing metaplasia with intestinal characteristics, and dysplastic and invasive cystic glands. Furthermore, mutant corpus showed marked chronic inflammation characterized by infiltration of lymphocytes and myeloid-derived suppressor cells along with the upregulation of innate and adaptive immune system components. Striking upregulation of inflammatory mediators and STAT3 activation was observed. Mechanistically, we determined there is an activation of ERK1/2 and downregulation of BMP/SMAD signaling characterized by marked upregulation of BMP inhibitor gremlin 1.ConclusionsWe report a novel role of PKA signaling in gastric MEC execution and show that PKA activation in the gastric mesenchyme drives preneoplasia by creating a proinflammatory and proproliferative microenvironment associated with the downregulation of BMP/SMAD signaling and activation of ERK1/2.

Epithelial X-Box Binding Protein 1 Coordinates Tumor Protein p53-Driven DNA Damage Responses and Suppression of Intestinal Carcinogenesis

Throughout life, the intestinal epithelium undergoes constant self-renewal from intestinal stem cells. Together with genotoxic stressors and failing DNA repair, this self-renewal causes susceptibility toward malignant transformation. X-box binding protein 1 (XBP1) is a stress sensor involved in the unfolded protein response (UPR). We hypothesized that XBP1 acts as a signaling hub to regulate epithelial DNA damage responses. Data from The Cancer Genome Atlas were analyzed for association of XBP1 with colorectal cancer (CRC) survival and molecular interactions between XBP1 and p53 pathway activity. The role of XBP1 in orchestrating p53-driven DNA damage response was tested invitro in mouse models of chronic intestinal epithelial cell (IEC) DNA damage (Xbp1/H2bfl/fl, Xbp1ΔIEC, H2bΔIEC, H2b/Xbp1ΔIEC) and via orthotopic tumor organoid transplantation. Transcriptome analysis of intestinal organoids was performed to identify molecular targets of Xbp1-mediated DNA damage response. In The Cancer Genome Atlas data set of CRC, low XBP1 expression was significantly associated with poor overall survival and reduced p53 pathway activity. Invivo, H2b/Xbp1ΔIEC mice developed spontaneous intestinal carcinomas. Orthotopic tumor organoid transplantation revealed a metastatic potential of H2b/Xbp1ΔIEC-derived tumors. RNA sequencing of intestinal organoids (H2b/Xbp1fl/fl, H2bΔIEC, H2b/Xbp1ΔIEC, and H2b/p53ΔIEC) identified a transcriptional program downstream of p53, in which XBP1 directs DNA-damage-inducible transcript 4-like (Ddit4l) expression. DDIT4L inhibits mechanistic target of rapamycin-mediated phosphorylation of 4E-binding protein 1. Pharmacologic mechanistic target of rapamycin inhibition suppressed epithelial hyperproliferation via 4E-binding protein1. Our data suggest a crucial role for XBP1 in coordinating epithelial DNA damage responses and stem cell function via a p53-DDIT4L-dependent feedback mechanism.

Pre-Clinical Assessment of Single-Use Negative Pressure Wound Therapy During In Vivo Porcine Wound Healing.

Objective: Traditional negative pressure wound therapy (tNPWT) systems can be large and cumbersome, limiting patient mobility and adversely affecting quality of life. PICO™, a no canister single-use system, offers a lightweight, portable alternative to tNPWT, with improved clinical performance. The aim of this study was to determine the potential mechanism(s) of action of single-use NPWT (sNPWT) versus tNPWT.Approach: sNPWT and tNPWT were applied to an in vivo porcine excisional wound model, following product use guidelines. Macroscopic, histological, and biochemical analyses were performed at defined healing time points to assess multiple aspects of the healing response.Results: Wounds treated with single-use negative pressure displayed greater wound closure and increased reepithelialization versus those treated with traditional negative pressure. The resulting granulation tissue was more advanced with fewer neutrophils, reduced inflammatory markers, more mature collagen, and no wound filler-associated foreign body reactions. Of note, single-use negative pressure therapy failed to induce wound edge epithelial hyperproliferation, while traditional negative pressure therapy compromised periwound skin, which remained inflamed with high transepidermal water loss; features not observed following single-use treatment.Innovation: Single-use negative pressure was identified to improve multiple aspects of healing versus traditional negative pressure treatment.Conclusion: This study provides important new insight into the differing mode of action of single-use versus traditional negative pressure and may go some way to explaining the improved clinical outcomes observed with single-use negative pressure therapy.

Ligand-Activated Peroxisome Proliferator-Activated Receptor β/δ Facilitates Cell Proliferation in Human Cholesteatoma Keratinocytes.

Cholesteatoma is characterized by both the overgrowth of hyperkeratinized squamous epithelium and bone erosion. However, the exact mechanism underlying the hyperproliferative ability of cholesteatoma remains unknown. In this study, we investigated PPAR β/δ expression in human surgical specimens of cholesteatoma and analyzed its functional role as a regulator of epithelial keratinocyte hyperproliferation. We found that the expression of PPAR β/δ was significantly upregulated in cholesteatoma and ligand-activated PPAR β/δ markedly promoted the proliferation of cholesteatoma keratinocytes. Furthermore, we showed that PPAR β/δ activation increased PDK1 expression and decreased PTEN generation, which led to increased phosphorylation of AKT and GSK3β and increased the expression level of Cyclin D1. Overall, our data suggested that the proliferating effect of PPAR β/δ on the cholesteatoma keratinocytes was mediated by the positive regulation of the PDK1/PTEN/AKT/GSK3β/Cyclin D1 pathway. These findings warranted further investigation of PPAR β/δ as a therapeutic target for recurrent or residual cholesteatoma.

FAM3D is essential for colon homeostasis and host defense against inflammation associated carcinogenesis

The physiological homeostasis of gut mucosal barrier is maintained by both genetic and environmental factors and its impairment leads to pathogenesis such as inflammatory bowel disease. A cytokine like molecule, FAM3D (mouse Fam3D), is highly expressed in mouse gastrointestinal tract. Here, we demonstrate that deficiency in Fam3D is associated with impaired integrity of colonic mucosa, increased epithelial hyper-proliferation, reduced anti-microbial peptide production and increased sensitivity to chemically induced colitis associated with high incidence of cancer. Pretreatment of Fam3D−/− mice with antibiotics significantly reduces the severity of chemically induced colitis and wild type (WT) mice co-housed with Fam3D−/− mice phenocopy Fam3D-deficiency showing increased sensitivity to colitis and skewed composition of fecal microbiota. An initial equilibrium of microbiota in cohoused WT and Fam3D−/− mice is followed by an increasing divergence of the bacterial composition after separation. These results demonstrate the essential role of Fam3D in colon homeostasis, protection against inflammation associated cancer and normal microbiota composition.

Abstract A16: Understanding the principles of tissue repair that accelerate tumor initiation

Abstract Cancer development depends on the capacity of malignant cells to boost growth-promoting signals and restrain growth-inhibiting mechanisms, thus resulting in unbalanced homeostasis. Among growth-promoting mechanisms, sustained proliferation has been described as a fundamental trait of cancer cells. Hyperproliferative behavior is usually acquired in cancer by the constitutive activation of oncogenes such as H-Ras (G12V activating mutation). Previous work showed that H-Ras-G12V promotes epithelial cell hyperproliferation, a feature required but not sufficient to trigger cancer formation. Interestingly, injury has been linked to skin cancer emergence across several mutations. Yet it remains elusive how wound-triggered behaviors lead to cancer. Wound repair process increases cell proliferation, a key event to re-establish epithelial integrity. This observation suggests a possible cooperation between wound-induced and H-Ras-driven proliferation to reach the homeostatic breaking point that promotes cancer. To understand if enhanced proliferation during wound repair could contribute to cancer emergence, I tested the sufficiency of this behavior in promoting tumor in H-RasG12V-model in comparison to other hyperproliferative models, loss of function of the cell cycle inhibitor p21 (p21-/-) and loss of function of Tgf-beta Receptor I (Tgf-beta-RI-/-). Interestingly, in both Tgf-beta-RI-/- and p21-/- models, despite wound-increased cell proliferation, the tissue repairs normally without emergence of tumor. Surprisingly, in H-RasG12V-model wound repair does not increase significantly proliferation, yet tumors consistently develop in the wounded area after two weeks, in line with previous studies. These results indicate that wound-induced proliferation is insufficient to promote tumor initiation. To determine how differences in H-RasG12V cell numbers affect the wound repair outcome, I have activated H-RasG12V mutation in a mosaic fashion, conditions under which H-Ras cells outcompete wild-type neighboring cells via hyperproliferation during homeostatic conditions (Pineda and Greco, in revision). Unexpectedly, the repaired epithelium does not develop tumor after two weeks. Analyses of cellular behaviors show that wild-type cells display an hyperproliferative behaviors in response to the wound settings and they appear to outcompete the H-Ras cells, reversing the relationship established in homeostatic conditions. These data show that wound-induced proliferation seems to provide homeostatic protection against tumor formation. Wild-type cells force Hras-mutant cells to follow physiologic wound repair process suppressing their tumorigenic potential. In conclusion, my discoveries suggest that hyperproliferation is dispensable for tumor initiation. Furthermore, enhanced proliferation of the wild-type population through wounding may help eliminate oncogenic mutant cells that would otherwise integrate and expand into the tissue. Citation Format: Sara Gallini, Valentina Greco. Understanding the principles of tissue repair that accelerate tumor initiation [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr A16.

Abstract P4-08-01: Tumor suppressor PLK2 may serve as a biomarker in triple negative breast cancer for combinational therapy of PLK1 inhibitors with the standard-of-care chemotherapy

Abstract Polo-like kinase (PLK) family members play important roles in cell cycle regulation. The founding member PLK1 is oncogenic and preclinically validated as a cancer therapeutic target. Surprisingly, PLK2 is frequently deleted in human breast cancer, preferentially in triple negative breast cancer (TNBC). Pilot studies using an RNAi screen and colony formation assays suggested that PLK2 might act as a tumor suppressor in breast cancer. This paradox stimulated us to investigate the functions of PLK1 and PLK2 in preclinical models and to understand their clinical implications. In preliminary experiments, we found that knockdown of PLK1 mitigated PLK2-deletion induced phenotypes including inhibiting colony formation, and rescued Plk2 null mammary epithelial cell phenotypes in vivo, including gland hyperbranching, epithelial cell hyperproliferation, and abnormal spindle orientation. Furthermore, we demonstrated that PLK2 interacted with PLK1 using a bimolecular fluorescence complementation assay and by co-immunoprecipitation, and using a proximity ligation assay this interaction was shown to occur in prometaphase. Due to the lack of targeted therapy, chemotherapy, such as carboplatin usually in combination with Taxol, is still one of the only systematic treatments for TNBC. Although PLK2 is frequently deleted in TNBC, there is currently no viable strategy to target this loss of function. The relationship between PLK2 and PLK1 suggests targeting PLK1 might provide a potential target to treat TNBC patients with loss of PLK2. In order to test this hypothesis, we used p53 null mammary epithelial cells as a sensitized background to generate a cohort of p53/Plk2 double null TNBC tumors. RNA-seq analysis showed that these tumors can be classified into three distinct molecular TNBC sublines: luminal-like, basal-like and claudin-low. Combinational treatment with the PLK1 inhibitor Volasertib and carboplatin showed a strong synergistic effect on tumor growth and led to regression of the Plk2/p53 null claudin-low tumors, but not control Plk2+/p53 null claudin-low tumors. The effect of combinational treatment of PLK1 inhibitor and carboplatin on the other two sublines as well as PLK2-low TNBC patient-derived xenograft (PDX) models is currently under investigation. We hope that these preclinical experiments will provide a rationale for the application PLK1 inhibitors in combination with chemotherapy in a subset of TNBC patients with deletion of PLK2. [Supported by Susan G. Komen Foundation grant SAC110031] Citation Format: Yang Gao, Elena Kabotyanski, Deanna Acosta, Elizabeth Villegas, Thomas F Westbrook, Charles M Perou, Jeffrey M Rosen. Tumor suppressor PLK2 may serve as a biomarker in triple negative breast cancer for combinational therapy of PLK1 inhibitors with the standard-of-care chemotherapy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-08-01.

HPV16 E7-Driven Epithelial Hyperplasia Promotes Impaired Antigen Presentation and Regulatory T-Cell Development

Human papillomaviruses infect keratinocytes and can lead to hyperproliferative dysplasia and malignant transformation if not cleared by the immune system. Human papillomavirus has evolved an array of mechanisms to evade and manipulate the immune system to improve replication efficiency and promote persistent infection. We here demonstrate that hyperproliferative skin expressing the high-risk human papillomavirus 16 E7 oncogene as a transgene drives immunomodulation of dendritic cells (DCs), resulting in reduced capacity to take up antigen and prime effector CD4+ T cell responses. The phenotype of DCs in the E7-expressing hyperproliferative skin was not reversible by activation through intradermal immunization. Naïve CD4+ T cells primed by E7-driven hyperproliferative skin acquired FoxP3 expression and an anergic phenotype. DC and T help modulation was dependent on E7-retinoblastoma protein interaction-driven epithelial hyperproliferation, rather than on expression of E7. Inhibition of binding of E7 to retinoblastoma protein, and of consequent epithelial hyperplasia, was associated with normal skin DC phenotype, and T helper type 1 effector responses to immunization were restored. We conclude that human papillomavirus-induced epithelial hyperplasia modulates epithelial DCs and inhibits T helper type 1 immunity while polarizing T-cell differentiation to a regulatory or anergic phenotype.