Tumor cell-intrinsic PD-1 promotes Merkel cell carcinoma growth by activating downstream mTOR-mitochondrial ROS signaling.

Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer. Inhibitors targeting the programmed cell death 1 (PD-1) immune checkpoint have improved MCC patient outcomes by boosting antitumor T cell immunity. Here, we identify PD-1 as a growth-promoting receptor intrinsic to MCC cells. In human MCC lines and clinical tumors, RT-PCR-based sequencing, immunoblotting, flow cytometry, and immunofluorescence analyses demonstrated PD-1 gene and protein expression by MCC cells. MCC-PD-1 ligation enhanced, and its inhibition or silencing suppressed, in vitro proliferation and in vivo tumor xenograft growth. Consistently, MCC-PD-1 binding to PD-L1 or PD-L2 induced, while antibody-mediated PD-1 blockade inhibited, protumorigenic mTOR signaling, mitochondrial (mt) respiration, and ROS generation. Last, pharmacologic inhibition of mTOR or mtROS reversed MCC-PD-1:PD-L1-dependent proliferation and synergized with PD-1 checkpoint blockade in suppressing tumorigenesis. Our results identify an MCC-PD-1-mTOR-mtROS axis as a tumor growth-accelerating mechanism, the blockade of which might contribute to clinical response in patients with MCC.

Robotic or laparoscopic repeat hepatectomy after open hepatectomy: a cohort study.

BACKGROUND: Repeat hepatectomies are technically complex procedures. The evidence of robotic or laparoscopic (= minimally invasive) repeat hepatectomies (MIRH) after previous open hepatectomy is poor. Therefore, we compared postoperative outcomes of MIRH vs open repeat hepatectomies (ORH) in patients with liver tumors after previous open liver resections. METHODS: Consecutive patients who underwent repeat hepatectomies after open liver resections were identified from a prospective database between April 2018 and May 2023. Postoperative complications were graded in line with the Clavien-Dindo classification. We stratified patients by intention to treat into MIRH or ORH and compared outcomes. Logistic regression analysis was performed to define variables associated with the utilization of a minimally invasive approach. RESULTS: Among 46 patients included, 20 (43%) underwent MIRH and 26 (57%) ORH. Twenty-seven patients had advanced or expert repeat hepatectomies (59%) according to the IWATE criteria. Baseline characteristics were comparable between the study groups. The use of a minimally invasive approach was not dependent on preoperative or intraoperative variables. All patients had negative resection margins on final histology. MIRH was associated with less blood loss (450 ml, IQR (interquartile range): 200-600 vs 600 ml, IQR: 400-1500 ml, P = 0.032), and shorter length of stay (5 days, IQR: 4-7 vs 7 days, IQR: 5-9 days, P = 0.041). Postoperative complications were similar between the groups (P = 0.298). CONCLUSIONS: MIRH is feasible after previous open hepatectomy and a safe alternative approach to ORH. (German Clinical Trials Register ID: DRKS00032183).

Development and Validation of a Model for Postpancreatectomy Hemorrhage Risk.

Importance: Postpancreatectomy hemorrhage (PPH) due to postoperative pancreatic fistula (POPF) is a life-threatening complication after pancreatoduodenectomy. However, there is no prediction tool for early identification of patients at high risk of late PPH. Objective: To develop and validate a prediction model for PPH. Design, Setting, and Participants: This retrospective prognostic study included consecutive patients with clinically relevant POPF who underwent pancreatoduodenectomy from January 1, 2009, to May 20, 2023, at the University Hospital Mannheim (derivation cohort), and from January 1, 2012, to May 31, 2022, at the University Hospital Dresden (validation cohort). Data analysis was performed from May 30 to July 29, 2023. Exposure: Clinical and radiologic features of PPH. Main Outcomes and Measures: Accuracy of a predictive risk score of PPH. A multivariate prediction model-the hemorrhage risk score (HRS)-was established in the derivation cohort (n = 139) and validated in the validation cohort (n = 154). Results: A total of 293 patients (187 [64%] men; median age, 69 [IQR, 60-76] years) were included. The HRS comprised 4 variables with associations: sentinel bleeding (odds ratio [OR], 35.10; 95% CI, 5.58-221.00; P < .001), drain fluid culture positive for Candida species (OR, 14.40; 95% CI, 2.24-92.20; P < .001), and radiologic proof of rim enhancement of (OR, 12.00; 95% CI, 2.08-69.50; P = .006) or gas within (OR, 12.10; 95% CI, 2.22-65.50; P = .004) a peripancreatic fluid collection. Two risk categories were identified with patients at low risk (0-1 points) and high risk (≥2 points) to develop PPH. Patients with PPH were predicted accurately in the derivation cohort (C index, 0.97) and validation cohort (C index 0.83). The need for more invasive PPH management (74% vs 34%; P < .001) and severe complications (49% vs 23%; P < .001) were more frequent in high-risk patients compared with low-risk patients. Conclusions and Relevance: In this retrospective prognostic study, a robust prediction model for PPH was developed and validated. This tool may facilitate early identification of patients at high risk for PPH.

Structural expression of bovine milk and meat factors in tissues of colorectal, lung and pancreatic cancer patients.

Chronic inflammation, linked to the presence of bovine milk and meat factors (BMMFs) and specific subsets of macrophages, results in oxygen radical synthesis and induction of mutations in DNA of actively replicating cells and replicating single stranded DNA. Cancers arising from this process have been characterized as indirect carcinogenesis by infectious agents (without persistence of genes of the agent in premalignant or cancers cells). Here, we investigate structural properties of pleomorphic vesicles, regularly identified by staining peritumor tissues of colorectal, lung and pancreatic cancer for expression of BMMF Rep. The latter represents a subgroup of BMMF1 proteins involved in replication of small single-stranded circular plasmids of BMMF, but most likely also contributing to pleomorphic vesicular structures found in the periphery of colorectal, lung and pancreatic cancers. Structurally dense regions are demonstrated in preselected areas of colorectal cancer, after staining with monoclonal antibodies against BMMF1 Rep. Similar structures were observed in human embryonic cells (HEK293TT) overexpressing Rep. These data suggest that Rep or Rep isoforms contribute to the structural formation of vesicles.

Comparison of extraction methods for intracellular metabolomics of human tissues.

Analyses of metabolic compounds inside cells or tissues provide high information content since they represent the endpoint of biological information flow and are a snapshot of the integration of many regulatory processes. However, quantification of the abundance of metabolites requires their careful extraction. We present a comprehensive study comparing ten extraction protocols in four human sample types (liver tissue, bone marrow, HL60, and HEK cells) aiming to detect and quantify up to 630 metabolites of different chemical classes. We show that the extraction efficiency and repeatability are highly variable across protocols, tissues, and chemical classes of metabolites. We used different quality metrics including the limit of detection and variability between replicates as well as the sum of concentrations as a global estimate of analytical repeatability of the extraction. The coverage of extracted metabolites depends on the used solvents, which has implications for the design of measurements of different sample types and metabolic compounds of interest. The benchmark dataset can be explored in an easy-to-use, interactive, and flexible online resource (R/shiny app MetaboExtract: http://www.metaboextract.shiny.dkfz.de) for context-specific selection of the optimal extraction method. Furthermore, data processing and conversion functionality underlying the shiny app are accessible as an R package: https://cran.r-project.org/package=MetAlyzer.

Inhibition of Melanoma Cell-Intrinsic Tim-3 Stimulates MAPK-Dependent Tumorigenesis.

T-cell immunoglobulin mucin family member 3 (Tim-3) is an immune checkpoint receptor that dampens effector functions and causes terminal exhaustion of cytotoxic T cells. Tim-3 inhibitors are under investigation in immuno-oncology (IO) trials, because blockade of T-cell-Tim-3 enhances antitumor immunity. Here, we identify an additional role for Tim-3 as a growth-suppressive receptor intrinsic to melanoma cells. Inhibition of melanoma cell-Tim-3 promoted tumor growth in both immunocompetent and immunocompromised mice, while melanoma-specific Tim-3 overexpression attenuated tumorigenesis. Ab-mediated Tim-3 blockade inhibited growth of immunogenic murine melanomas in T-cell-competent hosts, consistent with established antitumor effects of T-cell-Tim-3 inhibition. In contrast, Tim-3 Ab administration stimulated tumorigenesis of both highly and lesser immunogenic murine and human melanomas in T-cell-deficient mice, confirming growth-promoting effects of melanoma-Tim-3 antagonism. Melanoma-Tim-3 activation suppressed, while its blockade enhanced, phosphorylation of pro-proliferative downstream MAPK signaling mediators. Finally, pharmacologic MAPK inhibition reversed unwanted Tim-3 Ab-mediated tumorigenesis in T-cell-deficient mice and enhanced desired antitumor activity of Tim-3 interference in T-cell-competent hosts. These results identify melanoma-Tim-3 blockade as a mechanism that antagonizes T-cell-Tim-3-directed IO therapeutic efficacy. They further reveal MAPK targeting as a combination strategy for circumventing adverse consequences of unintended melanoma-Tim-3 inhibition. SIGNIFICANCE: Tim-3 is a growth-suppressive receptor intrinsic to melanoma cells, the blockade of which promotes MAPK-dependent tumorigenesis and thus counteracts antitumor activity of T-cell-directed Tim-3 inhibition.

Distinct antibody clones detect PD-1 checkpoint expression and block PD-L1 interactions on live murine melanoma cells.

Monoclonal antibodies (abs) targeting the programmed cell death 1 (PD-1) immune checkpoint pathway have revolutionized tumor therapy. Because T-cell-directed PD-1 blockade boosts tumor immunity, anti-PD-1 abs have been developed for examining T-cell-PD-1 functions. More recently, PD-1 expression has also been reported directly on cancer cells of various etiology, including in melanoma. Nevertheless, there is a paucity of studies validating anti-PD-1 ab clone utility in specific assay types for characterizing tumor cell-intrinsic PD-1. Here, we demonstrate reactivity of several anti-murine PD-1 ab clones and recombinant PD-L1 with live B16-F10 melanoma cells and YUMM lines using multiple independent methodologies, positive and negative PD-1-specific controls, including PD-1-overexpressing and PD-1 knockout cells. Flow cytometric analyses with two separate anti-PD-1 ab clones, 29F.1A12 and RMP1-30, revealed PD-1 surface protein expression on live murine melanoma cells, which was corroborated by marked enrichment in PD-1 gene (Pdcd1) expression. Immunoblotting, immunoprecipitation, and mass spectrometric sequencing confirmed PD-1 protein expression by B16-F10 cells. Recombinant PD-L1 also recognized melanoma cell-expressed PD-1, the blockade of which by 29F.1A12 fully abrogated PD-1:PD-L1 binding. Together, our data provides multiple lines of evidence establishing PD-1 expression by live murine melanoma cells and validates ab clones and assay systems for tumor cell-directed PD-1 pathway investigations.

Prognostic value of disease-free interval in colorectal cancer: Is it time?

BACKGROUND: Previous studies have outlined that the onset of synchronous colorectal cancer (CRC) metastases is associated with poor overall survival (OS) compared to patients with metachronous disease. The aim of this study was to evaluate the association of disease-free interval with newly diagnosed CRC scheduled for primary tumor resection. METHODS: Patients who underwent primary CRC resection over an 18-year period were identified from a prospective database at a tertiary-care hospital. In this observational study, the cohort was stratified for the onset of metastases, i.e. synchronous, early-onset and late-onset metachronous disease. The OS was compared using Kaplan-Meier estimators and stratified Cox hazard regression analysis. RESULTS: Of 360 patients, 204 (57%) had synchronous, 61 (17%) had early metachronous, and 95 (26%) had late metachronous metastases, respectively. The onset of synchronous metastases was not associated with worse OS compared to early and late metachronous disease. ASA level > II (P = 0.011), right-sided compared to left-sided cancer (P = 0.032) or rectal cancer (P < 0.001), and high-grade tumors (P = 0.022) were identified as independent predictors of poor OS, whereas the only favorable prognostic factor was surgical resection of metastases (P = 0.047). Additionally, ASA level < III (P = 0.003) and low-grade tumors (P = 0.032) were found to predict resection of metastases. CONCLUSION: Individual patients' and tumor characteristics rather than the timing of metastases are associated with OS in newly diagnosed CRC. These data support curative treatment strategies even in patients with synchronous metastases.

Minimally invasive mesohepatectomy for centrally located liver lesions-a case series.

BACKGROUND: Resection of centrally located liver lesions remains a technically demanding procedure. To date, there are limited data on the effectiveness and safety of minimally invasive mesohepatectomy for benign and malignant lesions. It was therefore the objective of this study to evaluate the perioperative outcomes of minimally invasive mesohepatectomy for liver tumors at a tertiary care hospital. METHODS: Consecutive patients who underwent a minimally invasive anatomic mesohepatectomy using a Glissonean pedicle approach from April 2018 to November 2021 were identified from a prospective database. Demographics, operative details, and postoperative outcomes were analyzed using descriptive statistics for continuous and categorical variables. RESULTS: A total of ten patients were included, of whom five patients had hepatocellular carcinoma, one patient had cholangiocarcinoma, three patients had colorectal liver metastases, and one patient had a hydatid cyst. Two and eight patients underwent robotic-assisted and laparoscopic resections, respectively. The median operative time was 393 min (interquartile range (IQR) 298-573 min). Conversion to laparotomy was required in one case. The median lesion size was 60 mm and all cases had negative resection margins on final histopathological analysis. The median total blood loss was 550 ml (IQR 413-850 ml). One patient had a grade III complication. The median length of stay was 7 days (IQR 5-12 days). Time-to-functional recovery was achieved after a median of 2 days (IQR 1-4 days). There were no readmissions within 90 days after surgery. CONCLUSION: Minimally invasive mesohepatectomy is a feasible and safe approach in selected patients with benign and malignant liver lesions.

Co-Medication and Nutrition in Hepatocellular Carcinoma: Potentially Preventative Strategies in Hepatocellular Carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide, with about 841,000 new cases and 782,000 deaths annually. Given the clearly defined population at risk, mostly patients with liver cirrhosis, prevention of HCC could be highly effective. SUMMARY: Besides regular ultrasound surveillance, numerous publications have suggested protective effects of diverse drugs and nutrients. However, none of those preventive options has made it into clinical routine or practice guidelines. We therefore summarize the current status of preventive effects of drugs such as statins, acetylsalicylic acid (ASA), and metformin, but also dietary aspects and nutrients such as coffee, tea, and vitamin D supplementation. A successful implementation of some of these strategies may potentially lead to improved prevention of HCC development in patients with liver cirrhosis. Key Messages: Accumulating data suggest that particularly ASA, antidiabetic therapies, and statins may substantially decrease HCC incidence in patients at risk.

Impact of intraoperative margin clearance on survival following pancreatoduodenectomy for pancreatic cancer: a systematic review and meta-analysis.

The use of intraoperative margin revision to achieve margin clearance in patients undergoing pancreatoduodenectomy for pancreatic cancer is controversial. We performed a systematic review and meta-analysis to summarize the evidence of intraoperative margin revisions of the pancreatic neck and its impact on overall survival (OS). Nine studies with 4501 patients were included. Patient cohort was stratified in an R0R0-group (negative margin on frozen and permanent section), R1R0-group (revised positive margin on frozen section which turned negative on permanent section), and R1R1-group (positive margin on frozen and permanent section despite margin revision). OS was higher in the R1R0-group (HR 0.83, 95% CI 0.72-0.96, P = 0.01) compared to the R1R1-group but lower compared to the R0R0-group (HR 1.20; 95% CI 1.05-1.37, P = 0.008), respectively. Subgroup analyses on the use of different margin clearance definitions confirmed an OS benefit in the R1R0-group compared to the R1R1-group (HR 0.81; 95% CI 0.65-0.99, P = 0.04). In conclusion, intraoperative margin clearance of the pancreatic neck margin is associated with improved OS while residual tumor indicates aggressive tumor biology. Consensus definitions on margin terminologies, clearance, and surgical techniques are required.

Obesity and Pancreatic Cancer: A Matched-Pair Survival Analysis.

BACKGROUND: Morbid obesity is a risk factor for pancreatic ductal adenocarcinoma (PDAC). However, the impact of obesity on postoperative outcomes and overall survival in patients with PDAC remains a controversial topic. METHODS: Patients who underwent pancreatic surgery for PDAC between 1997 and 2018 were included in this study. Matched pairs (1:1) were generated according to age, gender and American Society of Anesthesiologists status. Obesity was defined according to the WHO definition as BMI ≥ 30 kg/m2. The primary endpoint was the difference in overall survival between patients with and without obesity. RESULTS: Out of 553 patients, a total of 76 fully matched pairs were generated. Obese patients had a mean BMI-level of 33 compared to 25 kg/m2 in patients without obesity (p = 0.001). The frequency of arterial hypertension (p = 0.002), intraoperative blood loss (p = 0.039), and perineural invasion (p = 0.033) were also higher in obese patients. Clinically relevant postoperative complications (p = 0.163) and overall survival rates (p = 0.885) were comparable in both study groups. Grade II and III obesity resulted in an impaired overall survival, although this was not statistically significant. Subgroup survival analyses revealed no significant differences for completion of adjuvant chemotherapy and curative-intent surgery. CONCLUSIONS: Obesity did not affect overall survival and postoperative complications in these patients with PDAC. Therefore, pancreatic surgery should not be withheld from obese patients.

PAC1 deficiency attenuates progression of atherosclerosis in ApoE deficient mice under cholesterol-enriched diet.

The neuropeptide, pituitary adenylate cyclase-activating polypeptide (PACAP) is vasoactive and cytoprotective and exerts immunoregulatory functions throughout the nervous, neuroendocrine cardiovascular and immune systems in health and disease. PACAP mainly acts through PAC1 receptor signaling in neuronal communication, but the role of PAC1 in immune regulation of atherosclerosis is not known. Here, we generated PAC1-/-/ApoE-/- mice to test, whether PAC1-/- influences plasma cholesterol-/triglyceride levels and/or atherogenesis in the brachiocephalic trunk (BT) seen in ApoE-/- mice, under standard chow (SC) or cholesterol-enriched diet (CED). Furthermore, the effect of PAC1-/-, on inflammatory, autophagy-, apoptosis- and necroptosis-relevant proteins in atherosclerotic plaques was determined. In plaques of PAC1-/-/ApoE-/- mice fed a SC, the immunoreactivity for apoptotic, autophagic, necroptotic and proinflammatory proteins was increased, however, proliferation was unaffected. Interestingly, without affecting hyperlipidemia, PAC1-/- in ApoE-/- mice remarkably reduced CED-induced lumen stenosis seen in ApoE-/- mice. Thus, PAC1-/- allows unchecked inflammation, necroptosis and decreased proliferation during SC, apparently priming the BT to develop reduced atheroma under subsequent CED. Remarkably, no differences in inflammation/necroptosis signatures in the atheroma under CED between PAC1-/-/ApoE-/- and ApoE-/- mice were observed. These data indicate that selective PAC1 antagonists should offer potential as a novel class of atheroprotective therapeutics, especially during hypercholesterolemia.

Contralateral Liver Hypertrophy and Oncological Outcome Following Radioembolization with 90Y-Microspheres: A Systematic Review.

Radioembolization with 90Y-microspheres has been reported to induce contralateral liver hypertrophy with simultaneous ipsilateral control of tumor growth. The aim of the present systematic review was to summarize the evidence of contralateral liver hypertrophy and oncological outcome following unilateral treatment with radioembolization. A systematic literature search using the MEDLINE, EMBASE, and Cochrane libraries for studies published between 2008 and 2020 was performed. A total of 16 studies, comprising 602 patients, were included. The median kinetic growth rate per week of the contralateral liver lobe was 0.7% and declined slightly over time. The local tumor control was 84%. Surgical resection after radioembolization was carried out in 109 out of 362 patients (30%). Although the available data suggest that radioembolization prior to major hepatectomy is safe with a promising oncological outcome, the definitive role of radioembolization requires assessment within controlled clinical trials.

A systematic review and meta-analysis of caudate lobectomy for treatment of hilar cholangiocarcinoma.

BACKGROUND: Surgical resection remains the only potentially curative therapy for hilar cholangiocarcinoma (CCC) patients. This meta-analysis aimed to review the current evidence on perioperative and long-term outcomes of routine caudate lobe resection (CLR) for surgical treatment of hilar CCC. METHODS: A systematic literature search using MEDLINE, EMBASE and Cochrane databases was performed for studies providing comparative data on perioperative and long-term outcomes of patients undergoing resection for hilar CCC with and without CLR. The MINORS score was used for quality assessment. For time-to-event outcomes hazard ratios (HRs) and associated 95% CI were extracted from identified studies, whereas risk ratios (RRs) were calculated for overall morbidity, mortality, and resection margin status. Meta-analyses were carried out using random-effects models. RESULTS: Eight studies involving 1350 patients met the inclusion criteria. The quality of the included studies was low to moderate. CLR resulted in significantly improved overall survival (HR 0.49; 95%CI 0.32-0.75, P < 0.01). Postoperative morbidity (RR 0.93; 95% CI 0.77-1.13; P = 0.48) and mortality (RR 1.01; 95% CI 0.42-2.41; P = 0.99) rates were comparable between both groups. Patients without concomitant CLR were at higher risk for residual tumor at the resection margin (RR 1.40; 95% CI 1.09-1.80; P = 0.01). CONCLUSION: CLR is associated with improved long-term survival and negative tumor margins after resection of hilar CCC with no adverse impact on perioperative outcomes. CLR might provide the potential to become a standard-of-care procedure in the surgical management of hilar CCC.

Successful treatment of gastric necrosis after ingestion of hydrochloric acid: a two-stage minimally invasive surgical procedure.

Caustic ingestion may cause devastating injuries of the upper gastrointestinal tract and the respiratory system. We report here the successful treatment of a 37-year-old patient who ingested hydrochloric acid (100 mL; 24%) in suicidal intention. An oesophagogastroduodenoscopy revealed extensive necrosis of the gastric mucosa. A diagnostic laparoscopy was performed and confirmed the suspected transmural necrosis which resulted in a discontinuous laparoscopic gastrectomy. During the next days, the oesophageal stump was monitored through frequent oesophagoscopies and showed a good recovery. Thus, it was possible to restore continuity as early as by the sixth postoperative day performing a roux-en-y oesophagojejunostomy using the da Vinci Xi surgical robot. The patient underwent all procedures without any surgical complications and was discharged almost 1 month after initial presentation in good general condition.

PACAP deficiency aggravates atherosclerosis in ApoE deficient mice.

Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) plays an important role in cytoprotection, inflammation and cardiovascular regulation. Thus, we studied the involvement of PACAP in atherogenesis. Differentiated human THP-1 macrophages (MΦ) were stimulated with oxidized low-density lipoproteins (oxLDL) and the influence of PACAP38 treatment on lipid content and TNF release was determined. To test the effect of PACAP deficiency (PACAP-/-) on the development of atherosclerosis under standard chow (SC) or cholesterol-enriched diet (CED) in vivo, PACAP-/- mice were crossbred with ApoE-/- to generate PACAP-/-/ApoE-/- mice. Blood cholesterol and triglyceride levels were quantified. Lumen stenosis in the brachiocephalic trunk, cellularity and amounts of pro-inflammatory as well as autophagy-, apoptosis- and necroptosis-relevant proteins were analysed in atherosclerotic plaques by quantitative immunohistochemistry. In vitro, PACAP38 inhibited oxLDL-induced intracellular lipid storage as well as TNF release in MФ. In vivo, after SC, but not under CED, PACAP-/-/ApoE-/- mice showed an increased lumen stenosis compared to ApoE-/- mice. In atherosclerotic plaques of PACAP-/-/ApoE-/- mice, the immunoreactive areas of TNF+, IL-1ß+, autophagic, apoptotic and necroptotic cells were increased. In contrast, the overall cell density was decreased compared to ApoE-/- under SC, while no differences were seen under CED. Similar plasma cholesterol levels were observed in PACAP-/-/ApoE-/- and ApoE-/- mice under the respective feeding regime. Thus, PACAP-/-/ApoE-/- mice represent a novel mouse model of accelerated atherosclerosis where CED is not required. Our data indicate that PACAP acts as an endogenous atheroprotective neuropeptide. Thus, stable PACAP agonists may have potential as anti-atherosclerotic therapeutics. The specific PACAP receptor(s) mediating atheroprotection remain(s) to be identified.