Misc

Gamma-synuclein (SNCG) promotes invasive behavior and is reportedly a prognostic factor in a range of cancers. However, its role in biliary tract carcinoma (BTC) remains unknown. Consequently, we investigated the clinicopathological significance and function of SNCG in BTC. Using resected BTC specimens from 147 patients with adenocarcinoma (extrahepatic cholangiocarcinoma [ECC, n = 96]; intrahepatic cholangiocarcinoma [ICC, n = 51]), we immunohistochemically evaluated SNCG expression and investigated its correlation with clinicopathological factors and outcomes. Furthermore, cell lines with high SNCG expression were selected from 16 BTC cell lines and these underwent cell proliferation and migration assays by siRNAs. In the results, SNCG expression was present in 22 of 96 (22.9%) ECC patients and in 10 of 51 (19.6%) ICC patients. SNCG expression was significantly correlated with poorly differentiated tumor in both ECC and ICC (p = 0.01 and 0.03, respectively) and with perineural invasion and lymph node metastases in ECC (p = 0.04 and 0.003, respectively). Multivariate analyses revealed that SNCG expression was an independent poor prognostic factor in both OS and RFS in both ECC and ICC. In vitro analyses showed high SNCG expression in three BTC cell lines (NCC-BD1, NCC-BD3, and NCC-CC6-1). Functional analysis revealed that SNCG silencing could suppress cell migration in NCC-BD1 and NCC-CC6-1 and downregulate cell proliferation in NCC-CC6-1 significantly. In conclusion, SNCG may promote tumor cell activity and is potentially a novel prognostic marker in BTC.

The limited performance of guideline-recommended abdominal ultrasound and serum alpha-fetoprotein (AFP) highlights the urgent, unmet need for new biomarkers for more accurate detection of early hepatocellular carcinoma (HCC). To this end, we have conducted a prospective clinical validation study to evaluate the performance of the HelioLiver Test, a multi-analyte blood test combining cell-free DNA methylation patterns, clinical variables, and protein tumor markers. A blinded, multicenter validation study was performed with 247 subjects, including 122 subjects with HCC and 125 control subjects with chronic liver disease. The performance of the HelioLiver Test was compared with AFP and the GALAD score as established HCC surveillance blood tests. The performance of the HelioLiver Test (area under the receiver operating characteristic curve [AUROC] = 0.944) was superior to both AFP (AUROC = 0.851; p < 0.0001) and GALAD (AUROC = 0.899; p < 0.0001). Using a prespecified diagnostic algorithm, the HelioLiver Test showed sensitivities of 85% (95% confidence interval [CI], 78%–90%) for HCC of any stage and 76% (95% CI, 60%–87%) for early stage (American Joint Committee on Cancer [AJCC] I and II) HCC. In contrast, AFP (≥20 ng/mL) alone and the GALAD score (≥−0.63) showed lower sensitivities of 62% (95% CI, 54%–70%) and 75% (95% CI, 67%-82%) for HCC overall, and 57% (95% CI, 40%–71%) and 65% (95% CI, 49%–79%) for early stage (AJCC I and II) HCC, respectively. The specificities of the HelioLiver Test (91%; 95% CI, 85%–95%), AFP (97%; 95% CI, 92%–99%), and the GALAD score (94%; 95% CI, 88%–97%) were similar for control subjects. The HelioLiver Test showed superior performance for HCC detection compared to with both AFP and the GALAD score and warrants further evaluation in HCC surveillance settings.

Background & Aims: Despite recent progress, long-term survival remains low for hepatocellular carcinoma (HCC). The most effective HCC therapies target the tumor immune microenvironment (TIME), and there are almost no therapies that directly target tumor cells. Here, we investigated the regulation and function of tumor cell-expressed Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) in HCC. Methods: HCC was induced in mice by Sleeping Beauty-mediated expression of MET, CTNNB1-S45Y, or TAZ-S89A, or by diethylnitrosamine plus CCl4. Hepatocellular TAZ and YAP were deleted in floxed mice via adeno-associated virus serotype 8-mediated expression of Cre. TAZ target genes were identified from RNA sequencing, confirmed by chromatin immunoprecipitation, and evaluated in a clustered regularly interspaced short palindromic repeats interference (CRISPRi) screen. TEA domain transcription factors (TEADs), anillin (ANLN), Kif23, and programmed cell death protein ligand 1 were knocked down by guide RNAs in dead clustered regularly interspaced short palindromic repeats–associated protein 9 (dCas9) knock-in mice. Results: YAP and TAZ were up-regulated in murine and human HCC, but only deletion of TAZ consistently decreased HCC growth and mortality. Conversely, overexpression of activated TAZ was sufficient to trigger HCC. TAZ expression in HCC was regulated by cholesterol synthesis, as demonstrated by pharmacologic or genetic inhibition of 3-hydroxy-3-methylglutaryl- coenzyme A reductase (HMGCR), farnesyl pyrophosphate synthase, farnesyl-diphosphate farnesyltransferase 1 (FDFT1), or sterol regulatory element-binding protein 2 (SREBP2). TAZ- and MET/CTNNB1-S45Y–driven HCC required the expression of TEAD2 and, to a lesser extent, TEAD4. Accordingly, TEAD2 displayed the most profound effect on survival in patients with HCC. TAZ and TEAD2 promoted HCC via increased tumor cell proliferation, mediated by TAZ target genes ANLN and kinesin family member 23 (KIF23). Therapeutic targeting of HCC, using pan-TEAD inhibitors or the combination of a statin with sorafenib or anti–programmed cell death protein 1, decreased tumor growth. Conclusions: Our results suggest the cholesterol-TAZ-TEAD2-ANLN/KIF23 pathway as a mediator of HCC proliferation and tumor cell-intrinsic therapeutic target that could be synergistically combined with TIME-targeted therapies.

Immune checkpoint inhibitors (ICIs), despite their ability to potentiate antitumor T-cell responses, may cause various immune-related adverse events. Most cases of thrombocytopenia induced by ICIs have revealed a pathophysiologic mechanism of immune thrombocytopenia with increased platelet destruction and preserved megakaryocytes. Acquired amegakaryocytic thrombocytopenic purpura (AATP) is an unusual disorder characterized by thrombocytopenia with markedly diminished bone marrow megakaryocytes in the presence of otherwise normal hematopoiesis. AATP caused by ICIs has not been reported on. Herein, we present the case of a 79-year-old man diagnosed with squamous cell carcinoma of the lung who developed AATP after two courses of durvalumab, a drug targeting programmed death-ligand 1. Two weeks after the second cycle, his platelet count decreased to 2.1 × 104/μL. After the patient underwent platelet transfusion, his platelet count increased to 8.1 × 104/μL the next day but subsequently decreased repeatedly even after the ICI was discontinued. Six weeks after the second cycle, he developed interstitial pneumonia and was administered prednisolone (50 mg/day). However, thrombocytopenia did not improve. Bone marrow biopsy showed scarce megakaryocytes (< 1 megakaryocyte/10 high-power fields) with preservation of myeloid and erythroid series. Myelodysplasia, myelofibrosis, or metastatic lesions were not observed. Cytogenetic analysis showed a normal male karyotype of 46XY. Hence, the patient received eltrombopag, a thrombopoietin receptor agonist, and his platelet count subsequently improved. After recovery, bone marrow aspiration revealed a normal number of megakaryo-cytes. AATP is rarely the type of thrombocytopenia induced by ICIs and may be successfully treated with thrombopoietin receptor agonists.

A select group of patients with hepatocellular carcinomas (HCC) benefit from surgical, radiologic, and systemic therapies that include a combination of anti-angiogenic and immune-checkpoint inhibitors. However, because HCC is generally asymptomatic in its early stages, this not only leads to late diagnosis, but also to therapy resistance. The nucleoside analogue 6-thio-dG (THIO) is a first-in-class telomerase-mediated telomere-targeting anticancer agent. In telomerase expressing cancer cells, THIO is converted into the corresponding 5'-triphosphate, which is efficiently incorporated into telomeres by telomerase, activating telomere damage responses and apoptotic pathways. Here, we show how THIO is effective in controlling tumor growth and, when combined with immune checkpoint inhibitors, is even more effective in a T-cell-dependent manner. We also show telomere stress induced by THIO increases both innate sensing and adaptive antitumor immunity in HCC. Importantly, the extracellular high-mobility group box 1 protein acts as a prototypical endogenous DAMP (Damage Associated Molecular Pattern) in eliciting adaptive immunity by THIO. These results provide a strong rationale for combining telomere-targeted therapy with immunotherapy.

Effective tumor immunotherapy requires physical contact of T cells with cancer cells. However, tumors often constitute a specialized microenvironment that excludes T cells from the vicinity of cancer cells, and its underlying mechanisms are still poorly understood. DOCK2 is a Rac activator critical for migration and activation of lymphocytes. We herein show that cancer-derived cholesterol sulfate (CS), a lipid product of the sulfotransferase SULT2B1b, acts as a DOCK2 inhibitor and prevents tumor infiltration by effector T cells. Using clinical samples, we found that CS was abundantly produced in certain types of human cancers such as colon cancers. Functionally, CS-producing cancer cells exhibited resistance to cancer-specific T-cell transfer and immune checkpoint blockade. Although SULT2B1b is known to sulfate oxysterols and inactivate their tumor-promoting activity, the expression levels of cholesterol hydroxylases, which mediate oxysterol production, are low in SULT2B1b-expressing cancers. Therefore, SULT2B1b inhibition could be a therapeutic strategy to disrupt tumor immune evasion in oxysterol-non-producing cancers. Thus, our findings define a previously unknown mechanism for tumor immune evasion and provide a novel insight into the development of effective immunotherapies.