The Development of CDC25A-Derived Phosphoseryl Peptides That Bind 14-3-3ε with High Affinities.

Overexpression of the 14-3-3ε protein is associated with suppression of apoptosis in cutaneous squamous cell carcinoma (cSCC). This antiapoptotic activity of 14-3-3ε is dependent on its binding to CDC25A; thus, inhibiting 14-3-3ε - CDC25A interaction is an attractive therapeutic approach to promote apoptosis in cSCC. In this regard, designing peptide inhibitors of 14-3-3ε - CDC25A interactions is of great interest. This work reports the rational design of peptide analogs of pS, a CDC25A-derived peptide that has been shown to inhibit 14-3-3ε-CDC25A interaction and promote apoptosis in cSCC with micromolar IC50. We designed new peptide analogs in silico by shortening the parent pS peptide from 14 to 9 amino acid residues; then, based on binding motifs of 14-3-3 proteins, we introduced modifications in the pS(174-182) peptide. We studied the binding of the peptides using conventional molecular dynamics (MD) and steered MD simulations, as well as biophysical methods. Our results showed that shortening the pS peptide from 14 to 9 amino acids reduced the affinity of the peptide. However, substituting Gln176 with either Phe or Tyr amino acids rescued the binding of the peptide. The optimized peptides obtained in this work can be candidates for inhibition of 14-3-3ε - CDC25A interactions in cSCC.

Optimizing Phosphopeptide Structures That Target 14-3-3ε in Cutaneous Squamous Cell Carcinoma.

14-3-3ε is involved in various types of malignancies by increasing cell proliferation, promoting cell invasion, or inhibiting apoptosis. In cutaneous squamous cell carcinoma (cSCC), 14-3-3ε is overexpressed and mislocalized from the nucleus to the cytoplasm where it interacts with the cell division cycle 25 A (CDC25A) and suppresses apoptosis. Hence, inhibition of the 14-3-3ε-CDC25A interaction is an attractive target for promoting apoptosis in cSCC. In this work, we optimized the structure of our previously designed inhibitor of the 14-3-3ε-CDC25A interaction, pT, a phosphopeptide fragment corresponding to one of the two binding regions of CDC25A to 14-3-3ε. Starting from pT, we developed peptide analogs that bind 14-3-3ε with nanomolar affinities. Peptide analogs were designed by shortening the pT peptide and introducing modifications at position 510 of the pT(502-510) analog. Both molecular dynamics (MD) simulations and biophysical methods were used to determine peptide binding to 14-3-3ε. Shortening the pT peptide from 14 to 9 amino acid residues resulted in a peptide (pT(502-510)) that binds 14-3-3ε with a KD value of 45.2 nM. Gly to Phe substitution in position 510 of pT(502-510) led to further improvement in affinity (KD: 22.0 nM) of the peptide for 14-3-3ε. Our results suggest that the designed peptide analogs are potential candidates for inhibiting 14-3-3ε-CDC25A interactions in cSCC cells and thus inducing their apoptosis.

Effects of exogenous GIP and GLP-2 on bone turnover in individuals with type 2 diabetes.

CONTEXT: Individuals with type 2 diabetes (T2D) have an increased risk of bone fractures despite normal or increased bone mineral density (BMD). The underlying causes are not well understood but may include disturbances in the gut-bone axis, in which both glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-2 (GLP-2) are regulators of bone turnover. Thus, in healthy fasting participants, both exogenous GIP and GLP-2 acutely reduce bone resorption. OBJECTIVE: The objective of this study was to investigate the acute effects of subcutaneously administered GIP and GLP-2 on bone turnover in individuals with T2D. METHODS: We included 10 men with T2D. Participants met fasting in the morning on three separate test days and were injected subcutaneously with GIP, GLP-2, or placebo in a randomized crossover design. Blood samples were drawn at baseline and regularly after injections. Bone turnover was estimated by circulating levels of collagen type 1 C-terminal telopeptide (CTX), procollagen type 1 N-terminal propeptide (P1NP), sclerostin, and PTH. RESULTS: GIP and GLP-2 significantly reduced CTX to (mean ± SEM) 66 ± 7.8% and 74 ± 5.9% of baseline, respectively, compared with after placebo (p = 0.001). In addition, P1NP and sclerostin increased acutely after GIP whereas a decrease in P1NP was seen after GLP-2. PTH levels decreased to 67 ± 2.5% of baseline after GLP-2 and to only 86 ± 3.4% after GIP. CONCLUSION: Subcutaneous GIP and GLP-2 affect CTX and P1NP in individuals with T2D to the same extent as previously demonstrated in healthy individuals.

Optimizing Phosphopeptide Structures That Target 14-3-3ε in Cutaneous Squamous Cell Carcinoma.

14-3-3ε is involved in various types of malignancies by increasing cell proliferation, promoting cell invasion or inhibiting apoptosis. In cutaneous squamous cell carcinoma (cSCC), 14-3-3ε is over expressed and mislocalized from the nucleus to the cytoplasm where it interacts with the cell division cycle 25 A (CDC25A) and suppresses apoptosis. Hence inhibition of the 14-3-3ε - CDC25A interaction is an attractive target for promoting apoptosis in cSCC. In this work, we optimized the structure of our previously designed inhibitor of 14-3-3ε - CDC25A interaction, pT, a phosphopeptide fragment corresponding to one of the two binding regions of CDC25A to 14-3-3ε. Starting from pT, we developed peptide analogs that bind 14-3-3ε with nanomolar affinities. Peptide analogs were designed by shortening the pT peptide, and introducing modifications at position 510 of the pT(502-510) analog. Both molecular dynamics (MD) simulations and biophysical methods were used to determine peptides binding to 14-3-3ε. Shortening the pT peptide from 14 to 9 amino acid residues resulted in a peptide (pT(502-510)) that binds 14-3-3ε with a KD value of 45.2 nM. Gly to Phe substitution in position 510 of pT(502-510) led to further improvement in affinity (KD: 22.0 nM) of the peptide for 14-3-3ε. Our results suggest that the designed peptide analogs are potential candidates for inhibiting 14-3-3ε -CDC25A interactions in cSCC cells; thus, inducing their apoptosis.

Indocyanine green angiography in oncoplastic breast surgery, a prospective study.

INTRODUCTION: The use of Indocyanine green angiography (ICG-A) in oncoplastic breast-conserving surgery (OBCS) has not yet been investigated. This prospective trial applied ICG-A in volume displacement and replacement OBCS to localize perforators and determine tissue supplied by the perforator. Furthermore, to investigate and correlate the intraoperative ICG-A to postoperative surgical site infection, skin necrosis, epidermolysis, and timely onset of adjuvant therapy. METHODS: ICG-A was performed at three pre-set timepoints during surgery; after lumpectomy, upon dissection of possible perforators, and after wound closure. All patients were followed with clinical evaluations before surgery, 4 weeks, 4-6 months, and 12 months postoperatively. RESULTS: Eleven patients were included: seven volume displacement and four volume replacement OBCS. ICG-A located the tissue supplied by the perforator and demonstrated sufficient perfusion in all cases. The ICG-A corresponded to the surgeons' clinical assessment. One patient developed a postoperative infection and seroma and was treated conservatively. No patients had postoperative necrosis, loss of reconstruction, or lymphedema of the arm. Edema of the breast occurred in four patients (36.4%). Scar assessments were significantly worse at 4-weeks and 4-6 months. The quality of life improved significantly during follow-up. Adjuvant treatment was administered timely in all cases. CONCLUSION: ICG-A was feasible for OBCS in assessing intraoperative perfusion. Perfusion was sufficient in all patients and corresponded to the surgeon's clinical evaluation. No patients developed postoperative necrosis. Though edema of the breast occurred in 36.4%, a larger sample size is needed to investigate a possible correlation with ICG-A. Further studies, which includes patients requiring extensive tissue replacement challenging the borders of perfusion, are needed.

Surgical Rehabilitation for Research Residents: A Pilot Program to Offset Surgical Skill Decay.

OBJECTIVE: Select general surgery residents in the surgeon-scientist pipeline dedicate time away from clinical residency to conduct research. However, these research residents (RR) are vulnerable to operative skill decay. The aim of this study is to assess the feasibility of implementation and impact of an organized intervention designed to combat skill decay experienced by RR. DESIGN: RR were enrolled in a pilot Surgical Rehabilitation Program (SRP). The SRP is comprised of 12 cadaver-based simulation sessions and supplemented with Fundamentals of Laparoscopic Surgery-based simulation workouts. The RR were integrated with the clinical residents (CR) during the cadaver sessions and were subsequently performance tested, surveyed, and interviewed. SETTING: One academic general surgery residency program graduating 8 chief residents yearly in New York. PARTICIPANTS: General surgery CR and residents on dedicated research years. RESULTS: Data were collected for all local RR (n = 8) and 77% (n = 37) of CR. Local RR conducted research within the same health system that sponsors the residency. RR experienced gaps in training ranging from 2 to 4 years. All RR were permitted to moonlight on surgical services, however performed 0 operations and only 0.88 procedures on average per shift. Although RR performed similarly to level-matched CR on basic laparoscopic tasks, they required significantly more time on laparoscopic suturing-based skills than CR (p < 0.001). RR had significantly lower confidence levels precadaver sessions but gained confidence postcadaver sessions (p < 0.05), whereas CR confidence was unchanged. Regarding the SRP, qualitative interviews revealed major themes emphasizing the integration of RR, exposure to CR and faculty, technical skill development, maintenance of surgical know-how, and improved confidence for RR. CONCLUSIONS: The implementation of such structured interventions, like our SRP, aimed at supporting RR over gap years is essential to help residents maintain skills and confidence needed to achieve their goals of becoming surgeon scientists.

A randomized control trial of a combined community health worker and re-entry intervention for people with HIV recently released from jail who use substances.

INTRODUCTION: People with human immunodeficiency virus (HIV; PWH) who use substances are disproportionately involved in the criminal justice system. While HIV viral suppression typically improves during incarceration, these gains are frequently lost after release. We evaluated the impact of a combined intervention (formerly incarcerated community health workers [CHW] plus a re-entry organization; CHW+) on postrelease HIV- and substance use-related outcomes. METHODS: We conducted a pilot randomized controlled trial of a CHW+ for PWH who use substances, within 30 days of release from a large southern, urban jail. Between February 2019 and August 2021, participants were recruited, enrolled, and randomized to treatment as usual (TAU; passive referral to care) or CHW+. Follow up study visits occurred at 3, 6, and 12 months. The primary outcome was HIV VL at 6 months; secondary outcomes included 6-month urinary toxicology and high-risk substance use at 12 months. RESULTS: A total of 31 participants were enrolled who were primarily male (n = 24; 77 %), Black (n = 22; 71 %), unemployed (n = 23; 74.2 %), had unstable housing (n = 18; 58 %), had food insecurity (n = 14; 45 %), and reported their drug of choice was stimulants (n = 24; 77 %). The study identified no significant difference in HIV VL suppression at 6 months (20 % v. 37 %; [CHW+ v. TAU], p = 0.61). We observed improved substance use outcomes in CHW+ v. TAU, including fewer positive urinary toxicology screens for stimulants (40 % v. 100 %; p = 0.01) and a trend toward less high-risk substance use (30 % v. 43 %). The CHW+ group met more basic needs, such as food security [+32 % v. +11 %], housing security [+52 % v. -7 %] and full-time employment [+20 % v. +5 %] compared to TAU. CONCLUSIONS: PWH who use substances assigned to a combined intervention of CHW+ after jail release did not achieve higher rates of HIV VL suppression than TAU; however, they had improved substance use outcomes and met more basic subsistence needs. Results highlight the potential of culturally informed interventions to address the competing needs of PWH who use substances after release from jail and call for further development of innovative solutions to successfully bridge to HIV care in the community.

Social Media, Misinformation, and Online Patient Education in Emergency General Surgical Procedures.

INTRODUCTION: Patients use the internet to learn about diagnoses and treatment options. These sources vary in quality and accuracy of medical information. Thus, utilization of social media may lead to misinformation regarding treatment for patients in need of emergent general surgery procedures. METHODS: YouTube was searched with keywords "cholecystectomy," "cholecystitis," and "gallbladder surgery" and "appendectomy," "appendicitis," and "appendix surgery." For each procedure, the 100 videos with the greatest views were reviewed. Videos were assessed by four surgical trainees using validated instruments, DISCERN and the Patient Education Materials Assessment Tool (PEMAT), and Likert scales for patient education and misinformation. After appendectomy or cholecystectomy, patients completed a survey assessing use of social media preoperatively. RESULTS: The median DISCERN score was 28.0 of 75. The median PEMAT scores were 66.7% for understandability and 0% for actionability. Nearly half (49%) of videos provided no patient education and only 22% provided moderate or more. More than a third (35%) of videos contained misinformation. Doctors, medical education, and healthcare systems published videos with less misinformation, whereas patients, health/wellness groups published more misinformation (P < 0.001). Videos discoverable with colloquial terms "appendix surgery" and "gallbladder surgery" were more likely to contain misinformation (45.3%) compared to 20.5% of videos with misinformation discoverable using medical search terms only (P < 0.001). CONCLUSIONS: There is a range of video quality online with most videos of poor quality and provide little patient education. Understanding information available to patients online can tailor surgeon-patient discussions to combat misinformation and improve the informed consent process for patients.

The effect of early follow-up after open cardiac surgery in a student clinic.

Objectives. Readmission rates following open cardiac surgery are high, affecting patients and the cost of care. This study aimed to investigate the effect of early additional follow-up after open cardiac surgery when 5th-year medical students conducted follow-ups under the supervision of physicians. The primary endpoint was unplanned cardiac-related readmissions within one year. The secondary outcomes were the detection of impending complications and health-related quality of life (HRQOL). Methods. Patients undergoing open cardiac surgery were prospectively included. For intervention, additional follow-up visits, including point-of-care ultrasound, were conducted by supervised 5th-year medical students on postoperative days 3, 14 and 25. Unplanned cardiac-related readmissions, including emergency department visits, were registered within the first year of surgery. Danish National Health Survey 2010 questionnaire was used for HRQOL. In standard follow-up, all patients were seen 4-6 weeks postoperative. Results. For data analysis, 100 of 124 patients in the intervention group and 319 of 335 patients in the control group were included. The 1-year unplanned readmission rates did not differ; 32% and 30% in the intervention and control groups, respectively (p = 0.71). After discharge, 1% of patients underwent pericardiocentesis. The additional follow-up initiated scheduled drainage, contrary to more unscheduled/acute drainages in the control group. Pleurocentesis was more common in the intervention group (17% (n = 17) vs 8% (n = 25), p = 0.01) and performed earlier. There was no difference between groups on HRQOL. Conclusion. Supervised student-led follow-up of newly cardiac-operated patients did not alter readmission rates or HRQOL but may detect complications earlier and initiate non-emergent treatment of complications.

Acarbose diminishes postprandial suppression of bone resorption in patients with type 2 diabetes.

AIMS: The alpha-glucosidase inhibitor acarbose is an antidiabetic drug delaying assimilation of carbohydrates and, thus, increasing the amount of carbohydrates in the distal parts of the intestines, which in turn increases circulating levels of the gut-derived incretin hormone glucagon-like peptide 1 (GLP-1). As GLP-1 may suppress bone resorption, acarbose has been proposed to potentiate meal-induced suppression of bone resorption. We investigated the effect of acarbose treatment on postprandial bone resorption in patients with type 2 diabetes and used the GLP-1 receptor antagonist exendin(9-39)NH2 to disclose contributory effect of acarbose-induced GLP-1 secretion. METHODS: In a randomised, placebo-controlled, double-blind, crossover study, 15 participants with metformin-treated type 2 diabetes (2 women/13 men, age 71 (57-85 years), BMI 29.7 (23.6-34.6 kg/m2), HbA1c 48 (40-74 mmol/mol)/6.5 (5.8-11.6 %) (median and range)) were subjected to two 14-day treatment periods with acarbose and placebo, respectively, separated by a six-week wash-out period. At the end of each period, circulating bone formation and resorption markers were assessed during two randomised 4-h liquid mixed meal tests (MMT) with infusions of exendin(9-39)NH2 and saline, respectively. Glucagon-like peptide 2 (GLP-2) was also assessed. RESULTS: Compared to placebo, acarbose impaired the MMT-induced suppression of CTX as assessed by baseline-subtracted area under curve (P = 0.0037) and nadir of CTX (P = 0.0128). During acarbose treatment, exendin(9-39)NH2 infusion lowered nadir of CTX compared to saline (P = 0.0344). Neither parathyroid hormone or the bone formation marker procollagen 1 intact N-terminal propeptide were affected by acarbose or GLP-1 receptor antagonism. Acarbose treatment induced a greater postprandial GLP-2 response than placebo treatment (P = 0.0479) and exendin(9-39)NH2 infusion exacerbated this (P = 0.0002). CONCLUSIONS: In patients with type 2 diabetes, treatment with acarbose reduced postprandial suppression of bone resorption. Acarbose-induced GLP-1 secretion may contribute to this phenomenon as the impairment was partially reversed by GLP-1 receptor antagonism. Also, acarbose-induced reductions in other factors reducing bone resorption, e.g. glucose-dependent insulinotropic polypeptide, may contribute.

[Advanced locoregional chest wall recurrence of breast cancer].

Locoregional recurrence of breast cancer continues to be a significant clinical issue involving extensive examination programmes, modified oncologic therapy and advanced surgery. The latter includes tumour resection followed by reconstruction of the thoracic wall. The type of reconstruction depends on tumour location, depth, aetiology and whether the resection involves the stabilising osseous structures as summarised in this review. The treatment strategy is planned at multidisciplinary team conferences with the presence of relevant specialists to ensure evidence-based treatment of consistent quality.

Satellite Cell Expression of RAGE (Receptor for Advanced Glycation end Products) Is Important for Collateral Vessel Formation.

Background The growth and remodeling of vascular networks is an important component of the prognosis for patients with peripheral artery disease. One protein that has been previously implicated to play a role in this process is RAGE (receptor for advanced glycation end products). This study sought to determine the cellular source of RAGE in the ischemic hind limb and the role of RAGE signaling in this cell type. Methods and Results Using a hind limb ischemia model of vascular growth, this study found skeletal muscle satellite cells to be a novel major cellular source of RAGE in ischemic tissue by both staining and cellular sorting. Although wild-type satellite cells increased tumor necrosis factor-α and monocyte chemoattractant protein-1 production in response to ischemia in vivo and a RAGE ligand in vitro, satellite cells from RAGE knockout mice lacked the increase in cytokine production both in vivo in response to ischemia and in vitro after stimuli with the RAGE ligand high-mobility group box 1. Furthermore, encapsulated wild-type satellite cells improved perfusion after hind limb ischemia surgery by both perfusion staining and vessel quantification, but RAGE knockout satellite cells provided no improvement over empty capsules. Conclusions Thus, RAGE expression and signaling in satellite cells is crucial for their response to stimuli and angiogenic and arteriogenic functions.

Development and characterization of phasor-based analysis for FLIM to evaluate the metabolic and epigenetic impact of HER2 inhibition on squamous cell carcinoma cultures.

SIGNIFICANCE: Deranged metabolism and dysregulated growth factor signaling are closely associated with abnormal levels of proliferation, a recognized hallmark in tumorigenesis. Fluorescence lifetime imaging microscopy (FLIM) of endogenous nicotinamide adenine dinucleotide (NADH), a key metabolic coenzyme, offers a non-invasive, diagnostic indicator of disease progression, and treatment response. The model-independent phasor analysis approach leverages FLIM to rapidly evaluate cancer metabolism in response to targeted therapy. AIM: We combined lifetime and phasor FLIM analysis to evaluate the influence of human epidermal growth factor receptor 2 (HER2) inhibition, a prevalent cancer biomarker, on both nuclear and cytoplasmic NAD(P)H of two squamous cell carcinoma (SCC) cultures. While better established, the standard lifetime analysis approach is relatively slow and potentially subject to intrinsic fitting errors and model assumptions. Phasor FLIM analysis offers a rapid, model-independent alternative, but the sensitivity of the bound NAD(P)H fraction to growth factor signaling must also be firmly established. APPROACH: Two SCC cultures with low- and high-HER2 expression, were imaged using multiphoton-excited NAD(P)H FLIM, with and without treatment of the HER2 inhibitor AG825. Cells were challenged with mitochondrial inhibition and uncoupling to investigate AG825's impact on the overall metabolic capacity. Phasor FLIM and lifetime fitting analyses were compared within nuclear and cytoplasmic compartments to investigate epigenetic and metabolic impacts of HER2 inhibition. RESULTS: NAD(P)H fluorescence lifetime and bound fraction consistently decreased following HER2 inhibition in both cell lines. High-HER2 SCC74B cells displayed a more significant response than low-HER2 SCC74A in both techniques. HER2 inhibition induced greater changes in nuclear than cytoplasmic compartments, leading to an increase in NAD(P)H intensity and concentration. CONCLUSIONS: The use of both, complementary FLIM analysis techniques together with quantitative fluorescence intensity revealed consistent, quantitative changes in NAD(P)H metabolism associated with inhibition of growth factor signaling in SCC cell lines. HER2 inhibition promoted increased reliance on oxidative phosphorylation in both cell lines.

A Hydrogel Strategy to Augment Tissue Adenosine to Improve Hindlimb Perfusion.

[Figure: see text].

Targeting 14-3-3ε activates apoptotic signaling to prevent cutaneous squamous cell carcinoma.

More than a million cases of cutaneous squamous cell carcinoma are diagnosed in the USA each year, and its incidence is increasing. Most of these malignancies arise from premalignant lesions, providing an opportunity for intervention before malignant progression. We previously documented how cytoplasmic mislocalization of CDC25A in premalignant and malignant skin cancers confers resistance to apoptotic cell death via a mechanism that depends on its interaction with 14-3-3ε. From these data, we hypothesized that 14-3-3ε overexpression drives skin tumor development and progression, such that targeting 14-3-3ε may be a useful strategy for skin cancer treatment. Like CDC25A, 14-3-3ε was overexpressed and mislocalized to the cytoplasm of both benign and malignant human skin cancer. Skin-targeted deletion of the 14-3-3ε gene reduced skin tumor development by 75% and blocked malignant progression. 14-3-3ε suppressed apoptosis through activation of Akt, leading to inhibition of BCL2 associated agonist of cell death and upregulation of Survivin. Using virtual tetrapeptide libraries, we developed a novel peptide that specifically blocked 14-3-3ε heterodimerization and thereby prevented its interaction with CDC25A. The peptide reduced prosurvival signaling, killed skin cancer cells and reduced skin tumor growth in xenograft. Normal skin keratinocytes were unaffected by inhibition or deletion of 14-3-3ε. Thus, targeting of 14-3-3ε dimerization is a promising strategy for the treatment of premalignant skin lesions.

Targeting 14-3-3ε-CDC25A interactions to trigger apoptotic cell death in skin cancer.

Non-melanoma skin cancer is the most common form of cancer worldwide. We previously documented an anti-apoptotic role for CDC25A in cutaneous squamous cell carcinoma (SCC), an activity dependent on its association with 14-3-3 proteins. We hypothesized that targeting CDC25A-14-3-3ε interactions may be an effective strategy for inducing skin cancer cell apoptosis. Co-immunoprecipitation revealed that CDC25A associated with 14-3-3ε, 14-3-3γ and 14-3-3ζ in SCC cells but not normal keratinocytes. 14-3-3ε and CDC25A activated Akt/BAD/Survivin pro-survival signaling. To target the interaction of 14-3-3ε with CDC25A for cancer therapy, we developed two novel phospho-peptides, pS and pT, corresponding to each of the 14-3-3 binding sites of CDC25A, to specifically interfere with 14-3-3ε binding to CDC25A. Peptides pT (IC50 = 22.1 µM), and pS (IC50 = 29 µM) induced SCC cell death and blocked 14-3-3ε binding to CDC25A. pS or pT treatment of SCC xenografts increased apoptotic cell death and decreased pro-survival P-Akt (S473) and Survivin, demonstrating the effectiveness of the peptides in vivo. These findings lay a framework for the further development of peptides to target 14-3-3ε-CDC25A interactions for skin cancer treatment.

Targeted next-generation sequencing of matched localized and metastatic primary high-risk SCCs identifies driver and co-occurring mutations and novel therapeutic targets.

BACKGROUND: Cutaneous squamous cell carcinoma (SCC) is the second most common type of skin cancer and is responsible for over one million cases annually. While only 3-5 % of SCCs metastasize, those that do are associated with significant morbidity and mortality. Using gene mutations to help predict metastasis and select therapeutics is still being explored. OBJECTIVE: To present novel data from targeted sequencing of 20 case-matched localized and metastatic high-risk SCCs. METHODS: A cancer-associated gene panel of 76 genes was run from formalin-fixed paraffin-embedded samples of 20 case-matched localized (10) and metastatic (10) high-risk SCCs (Vela Diagnostics). RESULTS: Using spatial clustering analysis, primary driver mutations were identified asEGFR in localized SCC and CDH1 in metastatic SCC. ERBB4 and STK11 were found to be significant co-occurring mutations in localized SCC. Pathway analyses showed the RTK/RAS, TP53, TGF-b, NOTCH1, PI3K, and cell cycle pathways to be highly relevant in all high-risk SCCs with the Wnt pathway enhanced in metastatic SCC only. CONCLUSIONS: This study compared gene mutations between localized and metastatic SCC with the intent of identifying key differences and new potential targeted treatment options. To our knowledge, the co-occurrence ofERBB4 and STK11 mutations has not been previously reported. Targeted inhibition of CDH1 and the Wnt pathway should be further explored in metastatic SCC.

Flower isoforms promote competitive growth in cancer.

In humans, the adaptive immune system uses the exchange of information between cells to detect and eliminate foreign or damaged cells; however, the removal of unwanted cells does not always require an adaptive immune system1,2. For example, cell selection in Drosophila uses a cell selection mechanism based on 'fitness fingerprints', which allow it to delay ageing3, prevent developmental malformations3,4 and replace old tissues during regeneration5. At the molecular level, these fitness fingerprints consist of combinations of Flower membrane proteins3,4,6. Proteins that indicate reduced fitness are called Flower-Lose, because they are expressed in cells marked to be eliminated6. However, the presence of Flower-Lose isoforms at a cell's membrane does not always lead to elimination, because if neighbouring cells have similar levels of Lose proteins, the cell will not be killed4,6,7. Humans could benefit from the capability to recognize unfit cells, because accumulation of damaged but viable cells during development and ageing causes organ dysfunction and disease8-17. However, in Drosophila this mechanism is hijacked by premalignant cells to gain a competitive growth advantage18. This would be undesirable for humans because it might make tumours more aggressive19-21. It is unknown whether a similar mechanism of cell-fitness comparison is present in humans. Here we show that two human Flower isoforms (hFWE1 and hFWE3) behave as Flower-Lose proteins, whereas the other two isoforms (hFWE2 and hFWE4) behave as Flower-Win proteins. The latter give cells a competitive advantage over cells expressing Lose isoforms, but Lose-expressing cells are not eliminated if their neighbours express similar levels of Lose isoforms; these proteins therefore act as fitness fingerprints. Moreover, human cancer cells show increased Win isoform expression and proliferate in the presence of Lose-expressing stroma, which confers a competitive growth advantage on the cancer cells. Inhibition of the expression of Flower proteins reduces tumour growth and metastasis, and induces sensitivity to chemotherapy. Our results show that ancient mechanisms of cell recognition and selection are active in humans and affect oncogenic growth.

CDC25B and CDC25C overexpression in nonmelanoma skin cancer suppresses cell death.

Non-melanoma skin cancer frequently results from chronic exposure to ultraviolet (UV) irradiation. UV-induced DNA damage activates cell cycle arrest checkpoints through degradation of the cyclin-dependent kinase activators, the cell division cycle 25 (CDC25) phosphatases. We previously reported increased CDC25A in nonmelanoma skin cancer, but CDC25B and CDC25C had not been previously examined. Consequently, we hypothesized that increased expression of CDC25B and CDC25C increases tumor cell proliferation and skin tumor growth. We found that CDC25B and CDC25C were increased in mouse and human skin cancers. CDC25B was primarily cytoplasmic in skin and skin tumors and was significantly increased in the squamous cell carcinoma (SCC), while CDC25C was mostly nuclear in the skin, with an increased cytoplasmic signal in the premalignant and malignant tumors. Surprisingly, forced expression of CDC25B or CDC25C in cultured SCC cells did not affect proliferation, but instead suppressed apoptosis, while CDC25C silencing increased apoptosis without impacting proliferation. Targeting CDC25C to the nucleus via mutation of its nuclear export sequence, however, increased proliferation in SCC cells. Overexpression of CDC25C in the nuclear compartment did not hinder the ability of CDC25C to suppress apoptosis, neither did mutation of sites necessary for its interaction with 14-3-3 proteins. Analysis of apoptotic signaling pathways revealed that CDC25C increased activating phosphorylation of Akt on Ser473 , increased inhibitory phosphorylation of proapoptotic BAD on Ser136 , and increased the survival protein Survivin. Silencing of CDC25C significantly reduced Survivin levels. Taken together, these data suggest that increased expression of CDC25B or CDC25C are mechanisms by which skin cancers evade apoptotic cell death.

Aberrant localization of signaling proteins in skin cancer: Implications for treatment.

Aberrant subcellular localization of signaling proteins can provide cancer cells with advantages such as resistance to apoptotic cell death, increased invasiveness and more rapid proliferation. Nuclear to cytoplasmic shifts in tumor-promoting proteins can lead to worse patient outcomes, providing opportunities to target cancer-specific processes. Herein, we review the significance of dysregulated protein localization with a focus on skin cancer. Altered localization of signaling proteins controlling cell cycle progression or cell death is a common feature of cancer. In some instances, aberrant subcellular localization results in an acquired prosurvival function. Taking advantage of this knowledge reveals novel targets useful in the development of cancer therapeutics.