LCK inhibition downregulates YAP activity and is therapeutic in patient-derived models of cholangiocarcinoma.

BACKGROUND & AIMS: There is an unmet need to develop novel, effective medical therapies for cholangiocarcinoma (CCA). The Hippo pathway effector, Yes-associated protein (YAP), is oncogenic in CCA, but has historically been difficult to target therapeutically. Recently, we described a novel role for the LCK proto-oncogene, Src family tyrosine kinase (LCK) in activating YAP through tyrosine phosphorylation. This led to the hypothesis that LCK is a viable therapeutic target in CCA via regulation of YAP activity. METHODS: A novel tyrosine kinase inhibitor with relative selectivity for LCK, NTRC 0652-0, was pharmacodynamically profiled in vitro and in CCA cells. A panel of eight CCA patient-derived organoids were characterized and tested for sensitivity to NTRC 0652-0. Two patient-derived xenograft models bearing fibroblast growth factor receptor 2 (FGFR2)-rearrangements were utilized for in vivo assessment of pharmacokinetics, toxicity, and efficacy. RESULTS: NTRC 0652-0 demonstrated selectivity for LCK inhibition in vitro and in CCA cells. LCK inhibition with NTRC 0652-0 led to decreased tyrosine phosphorylation, nuclear localization, and co-transcriptional activity of YAP, and resulted in apoptotic cell death in CCA cell lines. A subset of tested patient-derived organoids demonstrated sensitivity to NTRC 0652-0. CCAs with FGFR2 fusions were identified as a potentially susceptible and clinically relevant genetic subset. In patient-derived xenograft models of FGFR2 fusion-positive CCA, daily oral treatment with NTRC 0652-0 resulted in stable plasma and tumor drug levels, acceptable toxicity, decreased YAP tyrosine phosphorylation, and significantly decreased tumor growth. CONCLUSIONS: A novel LCK inhibitor, NTRC 0652-0, inhibited YAP signaling and demonstrated preclinical efficacy in CCA cell lines, and patient-derived organoid and xenograft models. IMPACT AND IMPLICATIONS: Although aberrant YAP activation is frequently seen in CCA, YAP targeted therapies are not yet clinically available. Herein we show that a novel LCK-selective tyrosine kinase inhibitor (NTRC 0652-0) effectively inhibits YAP tyrosine phosphorylation and cotranscriptional activity and is well tolerated and cytotoxic in multiple preclinical models. The data suggest this approach may be effective in CCA with YAP dependence or FGFR2 fusions, and these findings warrant further investigation in phase I clinical trials.

Robotic-assisted bronchoscopy versus CT-guided transthoracic biopsy for diagnosis of pulmonary nodules.

BACKGROUND AND OBJECTIVE: Currently, computed tomography-guided transthoracic biopsy (CTTB) is the most accurate diagnostic approach for pulmonary nodules suspected of malignancy. Traditional bronchoscopy has shown suboptimal diagnostic sensitivity, but the emergence of robotic-assisted bronchoscopy (RAB) has the potential to improve diagnostic accuracy, maximize diagnostic yield and complete mediastinal and hilar staging in a single procedure. We aim to assess the efficacy and diagnostic performance of RAB compared to CTTB for diagnosing pulmonary nodules suspected of lung cancer. METHODS: A multicenter retrospective review of consecutive patients who underwent RAB and CTTB for evaluating pulmonary nodules from January 2019 to March 2021 at Mayo Clinic Florida and Mayo Clinic Rochester, United States. Clinical and demographic information, nodule characteristics, outcomes and complications were compared between RAB and CTTB. RESULTS: A total of 225 patients were included: 113 in the RAB group and 112 in the CTTB group. Overall diagnostic yield was 87.6% for RAB and 88.4% for CTTB. For malignant disease, RAB had a sensitivity of 82.1% and a specificity of 100%, CTTB had a sensitivity of 88.5% and a specificity of 100%. Complication rate was significantly higher for CTTB compared to RAB (17% vs. 4.4%; p = 0.002). CONCLUSION: RAB, when available, can be as accurate as CTTB for sampling pulmonary nodules with similar or reduced complications and should be considered as a means for nodule biopsy, particularly when mediastinal staging is also clinically warranted.

SHP2 inhibition enhances Yes-associated protein-mediated liver regeneration in murine partial hepatectomy models.

Disrupted liver regeneration following hepatectomy represents an "undruggable" clinical challenge associated with poor patient outcomes. Yes-associated protein (YAP), a transcriptional coactivator that is repressed by the Hippo pathway, is instrumental in liver regeneration. We have previously described an alternative, Hippo-independent mechanism of YAP activation mediated by downregulation of protein tyrosine phosphatase nonreceptor type 11 (PTPN11, also known as SHP2) inhibition. Herein, we examined the effects of YAP activation with a selective SHP1/SHP2 inhibitor, NSC-87877, on liver regeneration in murine partial hepatectomy models. In our studies, NSC-87877 led to accelerated hepatocyte proliferation, improved liver regeneration, and decreased markers of injury following partial hepatectomy. The effects of NSC-87877 were lost in mice with hepatocyte-specific Yap/Taz deletion, and this demonstrated dependence on these molecules for the enhanced regenerative response. Furthermore, administration of NSC-87877 to murine models of nonalcoholic steatohepatitis was associated with improved survival and decreased markers of injury after hepatectomy. Evaluation of transcriptomic changes in the context of NSC-87877 administration revealed reduction in fibrotic signaling and augmentation of cell cycle signaling. Cytoprotective changes included downregulation of Nr4a1, an apoptosis inducer. Collectively, the data suggest that SHP2 inhibition induces a pro-proliferative and cytoprotective enhancement of liver regeneration dependent on YAP.

The YAP-Interacting Phosphatase SHP2 Can Regulate Transcriptional Coactivity and Modulate Sensitivity to Chemotherapy in Cholangiocarcinoma.

The Hippo pathway effector Yes-associated protein (YAP) is localized to the nucleus and transcriptionally active in a number of tumor types, including a majority of human cholangiocarcinomas. YAP activity has been linked to chemotherapy resistance and has been shown to rescue KRAS and BRAF inhibition in RAS/RAF-driven cancers; however, the underlying mechanisms of YAP-mediated chemoresistance have yet to be elucidated. Herein, we report that the tyrosine phosphatase SHP2 directly regulates the activity of YAP by dephosphorylating pYAPY357 even in the setting of RAS/RAF mutations, and that diminished SHP2 phosphatase activity is associated with chemoresistance in cholangiocarcinomas. A screen for YAP-interacting tyrosine phosphatases identified SHP2, and characterization of cholangiocarcinomas cell lines demonstrated an inverse relationship between SHP2 levels and pYAPY357. Human sequencing data demonstrated lower SHP2 levels in cholangiocarcinomas tumors as compared with normal liver. Cell lines with low SHP2 expression and higher levels of pYAPY357 were resistant to gemcitabine and cisplatin. In cholangiocarcinomas cells with high levels of SHP2, pharmacologic inhibition or genetic deletion of SHP2 increased YAPY357 phosphorylation and expression of YAP target genes, including the antiapoptotic regulator MCL1, imparting resistance to gemcitabine and cisplatin. In vivo evaluation of chemotherapy sensitivity demonstrated significant resistance in xenografts with genetic deletion of SHP2, which could be overcome by utilizing an MCL1 inhibitor. IMPLICATIONS: These findings demonstrate a role for SHP2 in regulating YAP activity and chemosensitivity, and suggest that decreased phosphatase activity may be a mechanism of chemoresistance in cholangiocarcinoma via a MCL1-mediated mechanism.

Is Speed a Desirable Difficulty for Learning Procedures? An Initial Exploration of the Effects of Chronometric Pressure.

PURPOSE: To determine whether "chronometric pressure" (i.e., a verbal prompt to increase speed) could predictably alter medical learners' speed-accuracy trade-off during a simulated surgical task, thus modifying the challenge. METHOD: The authors performed a single-task, interrupted time-series study, enrolling surgery residents and medical students from two institutions in September and October 2015. Participants completed 10 repetitions of a simulated blood vessel ligation (placement of two ligatures 1 cm apart). Between repetitions 5 and 6, participants were verbally encouraged to complete the next repetition 20% faster than the previous one. Outcomes included time and accuracy (ligature tightness, placement distance). Data were analyzed using random-coefficients spline models. RESULTS: The authors analyzed data from 78 participants (25 medical students, 16 first-year residents, 37 senior [second-year or higher] residents). Overall, time decreased from the 1st (mean [standard deviation] 39.8 seconds [18.4]) to the 10th (29.6 [12.5]) repetition. The spline model showed a decrease in time between repetitions 5 and 6 of 8.6 seconds (95% confidence interval: -11.1, -6.1). The faster time corresponded with declines in ligature tightness (unadjusted difference -19%; decrease in odds 0.86 [0.76, 0.98]) and placement accuracy (unadjusted difference -5%; decrease in odds 0.86 [0.75, 0.99]). Significant differences in the speed-accuracy trade-off were seen by training level, with senior residents demonstrating the greatest decline in accuracy as speed increased. CONCLUSIONS: Chronometric pressure influenced the speed-accuracy trade-off and modified the challenge level in a simulated surgical task. It may help unmask correctable deficiencies or false plateaus in learners' skill development.

Validation of a Novel Inverted Peg Transfer Task: Advancing Beyond the Regular Peg Transfer Task for Surgical Simulation-Based Assessment.

OBJECTIVE: To evaluate the validity of a novel inverted peg transfer (iPT) task for assessing laparoscopic skills of novices and experts and compare iPT to the regular PT (rPT) task to ensure surgical trainee acquisition of an adequate advanced laparoscopic skills level for safe laparoscopic practice in the operating room. DESIGN: Prospective crossover study. SETTING: Multidisciplinary simulation center and motion analysis laboratory, Mayo Clinic. PARTICIPANTS: Novices were medical students and surgical interns without laparoscopic experience. Experts were surgeons with at least 3 years of experience in laparoscopic surgery. METHODS: This was the first exposure to iPT for both groups. Completion time and performance metrics were recorded. A scoring rubric was used to calculate a normalized performance score between 0 and 100. Wilcoxon rank sum and Mann-Whitney tests were performed with α = 0.05. Receiver-operating characteristic curves were graphed for the 2 task scores to assess the tasks' sensitivity and specificity in differentiating laparoscopic experience level. MAIN OUTCOME MEASURES: Performance measures of completion time, transferred triangles, dropped triangles (errors), and the overall performance score on both tasks between- and within-subjects (i.e., novices and experts). RESULTS: Thirty-six novices and eight experts participated. Both experts and novices had longer completion time and lower scores during iPT than rPT (p < 0.05). Within iPT, novice completion times were 144 seconds longer (p = 0.04), and performance score was 35 points lower than experts (p < 0.01). No differences between novices and experts were observed for completion time or performance scores (p > 0.05) for rPT. The iPT scores had a higher sensitivity and specificity than the rPT (area under the receiver-operating characteristic curve: iPT = 0.91; rPT = 0.69). CONCLUSIONS: iPT is a valid assessment of advanced laparoscopic skills for surgical trainees with higher specificity and sensitivity than rPT. As advanced minimally invasive surgery becomes more common, it is important that tasks such as iPT be included in surgical simulation curricula and training assessment.

Influence of Social Media on the Dissemination of a Traditional Surgical Research Article.

OBJECTIVE: Many institutions use social media to share research with the general public. However, the influence of social media on the dissemination of a surgical research article itself is unknown. Our objective was to determine whether a blog post highlighting the findings of a surgical research article would lead to increased dissemination of the article itself. DESIGN: We prospectively followed the online page views of an article that was published online in Surgery in May 2015 and published in print in August 2015. The authors subsequently released a blog post in October 2015 to promote the research. The number of article page views from the journal's website was obtained before and after the blog post, along with the page views from the blog post itself. Social media influence data were collected, including social activity in the form of mentions on social media sites, scholarly activity in online libraries, and scholarly commentary. RESULTS: The article's online activity peaked in the first month after online publication (475 page views). Online activity plateaued by 4 months after publication, with 118 monthly page views, and a blog post was subsequently published. The blog post was viewed by 1566 readers, and readers spent a mean of 2.5 minutes on the page. When compared to the projected trend, the page views increased by 33% in the month after the blog post. The blog post resulted in a 9% increase in the social media influence score and a 5% absolute increase in total article page views. CONCLUSIONS: Social media is an important tool for sharing surgical research. Our data suggest that social media can increase distribution of an article's message and also potentially increase dissemination of the article itself. We believe that authors should consider using social media to increase the dissemination of traditionally published articles.

Does scripting operative plans in advance lead to better preparedness of trainees? A pilot study.

BACKGROUND: We pondered if preoperative scripting might better prepare residents for the operating room (OR). METHODS: Interns rotating on a general surgeon's service were instructed to script randomized cases prior to entering the OR. Scripts contained up to 20 points highlighting patient information perceived important for surgical management. The attending was blinded to the scripting process and completed a feedback sheet (Likert scale) following each procedure. Feedback questions were categorized into "preparedness" (aware of patient specific details, etc.) and "performance" (provided better assistance, etc.). RESULTS: Eight surgical interns completed 55 scripted and 61 non-scripted cases. Total scores were higher in scripted cases (p = 0.02). Performance scores were higher for scripted cases (3.31 versus 3.13, p = 0.007), while preparedness did not differ (3.65 and 3.62, p = 0.51). CONCLUSIONS: This pilot study suggests scripting cases may be a useful preoperative planning tool to increase interns' operative and patient care performance but may not affect perceived preparedness.

At Home Preresidency Preparation for General Surgery Internship: A Pilot Study.

OBJECTIVE: To create a novel "at-home" preresidency preparatory adjunct for medical students entering surgical residency. DESIGN: Preparatory resources were mailed to match medical students before residency matriculation in 2015. This included "how-to" videos, low-cost models, and surgical instruments for 5 "stations" (arterial blood gas analysis, anatomy and imaging knowledge, knot tying ability, and suturing dexterity) of our program's biannual general surgery intern objective assessment activity (Surgical Olympics: total 13 stations, 10 points each). Scores from 2015 were compared with 2014 historical controls in a retrospective manner using the Student's t-test. SETTING: Academic, tertiary care referral center with a large general surgery training program. PARTICIPANTS: Postgraduate year 1 general surgery trainees (interns) from the years 2014 and 2015. RESULTS: Twenty-six interns participated in the 2015 assessment and were compared to thirty-two 2014 interns. Overall mean scores were low, but higher (19.7 vs. 15.4, p = 0.04) in the 2015 class. The largest increase was noted in the anatomy knowledge station (mean = 5.0 vs. 1.9, p < 0.01). Scores in stations assessing technical competence were similar to controls. The number of perfect scores among the 5 stations was higher (10 vs. 5) in the 2015 group. Mean scores from the other 8 stations, for which no resources were mailed, showed no difference (29.3 vs. 28.3, p = 0.75). CONCLUSIONS: Enacting a simple, home-based curriculum for medical students before surgical residency, improved performance on early knowledge assessments.

Objective Assessment of General Surgery Residents Followed by Remediation.

OBJECTIVE: Surgical training programs often lack objective assessment strategies. Complicated scheduling characteristics frequently make it difficult for surgical residents to undergo formal assessment; actually having the time and opportunity to remediate poor performance is an even greater problem. We developed a novel methodology of assessment for residents and created an efficient remediation system using a combination of simulation, online learning, and self-assessment options. DESIGN: Postgraduate year (PGY) 2 to 5 general surgery (GS) residents were tested in a 5 station, objective structured clinical examination style event called the Surgical X-Games. Stations were 15 minutes in length and tested both surgical knowledge and technical skills. Stations were scored on a scale of 1 to 5 (1 = Fail, 2 = Mediocre, 3 = Pass, 4 = Good, and 5 = Stellar). Station scores ≤ 2 were considered subpar and required remediation to a score ≥ 4. Five remediation sessions allowed residents the opportunity to practice the stations with staff surgeons. Videos of each skill or test of knowledge with clear instructions on how to perform at a stellar level were offered. Trainees also had the opportunity to checkout take-home task trainers to practice specific skills. Residents requiring remediation were then tested again in-person or sent in self-made videos of their performance. SETTING: Academic medical center. PARTICIPANTS: PGY2, 3, 4, and 5 GS residents at Mayo Clinic in Rochester, MN. RESULTS: A total of, 35 residents participated in the Surgical X-Games in the spring of 2015. Among all, 31 (89%) had scores that were deemed subpar on at least 1 station. Overall, 18 (58%) residents attempted remediation. All 18 (100%) achieved a score ≥ 4 on the respective stations during a makeup attempt. Overall X-Games scores and those of PGY2s, 3s, and 4s were higher after remediation (p < 0.05). No PGY5s attempted remediation. CONCLUSIONS: Despite difficulties with training logistics and busy resident schedules, it is feasible to objectively assess most GS trainees and offer opportunities to remediate if performance is poor. Our multifaceted remediation methodology allowed 18 residents to achieve good or stellar performance on each station after deliberate practice. Enticing chief residents to participate in remediation efforts in the spring of their final year of training remains a work in progress.