SMYD5 methylation of rpL40 links ribosomal output to gastric cancer.

Dysregulated transcription due to disruption in histone lysine methylation dynamics is an established contributor to tumorigenesis1,2. However, whether analogous pathologic epigenetic mechanisms act directly on the ribosome to advance oncogenesis is unclear. Here we find that trimethylation of the core ribosomal protein L40 (rpL40) at lysine 22 (rpL40K22me3) by the lysine methyltransferase SMYD5 regulates mRNA translation output to promote malignant progression of gastric adenocarcinoma (GAC) with lethal peritoneal ascites. A biochemical-proteomics strategy identifies the monoubiquitin fusion protein partner rpL40 (ref. 3) as the principal physiological substrate of SMYD5 across diverse samples. Inhibiting the SMYD5-rpL40K22me3 axis in GAC cell lines reprogrammes protein synthesis to attenuate oncogenic gene expression signatures. SMYD5 and rpL40K22me3 are upregulated in samples from patients with GAC and negatively correlate with clinical outcomes. SMYD5 ablation in vivo in familial and sporadic mouse models of malignant GAC blocks metastatic disease, including peritoneal carcinomatosis. Suppressing SMYD5 methylation of rpL40 inhibits human cancer cell and patient-derived GAC xenograft growth and renders them hypersensitive to inhibitors of PI3K and mTOR. Finally, combining SMYD5 depletion with PI3K-mTOR inhibition and chimeric antigen receptor T cell administration cures an otherwise lethal in vivo mouse model of aggressive GAC-derived peritoneal carcinomatosis. Together, our work uncovers a ribosome-based epigenetic mechanism that facilitates the evolution of malignant GAC and proposes SMYD5 targeting as part of a potential combination therapy to treat this cancer.

Atlas of Metastatic Gastric Cancer Links Ferroptosis to Disease Progression and Immunotherapy Response.

BACKGROUND & AIMS: Metastases from gastric adenocarcinoma (GAC) lead to high morbidity and mortality. Developing innovative and effective therapies requires a comprehensive understanding of the tumor and immune biology of advanced GAC. Yet, collecting matched specimens from advanced, treatment-naïve patients with GAC poses a significant challenge, limiting the scope of current research, which has focused predominantly on localized tumors. This gap hinders deeper insight into the metastatic dynamics of GAC. METHODS: We performed in-depth single-cell transcriptome and immune profiling on 68 paired, treatment-naïve, primary metastatic tumors to delineate alterations in cancer cells and their tumor microenvironment during metastatic progression. To validate our observations, we conducted comprehensive functional studies both in vitro and in vivo, using cell lines and multiple patient-derived xenograft and novel mouse models of GAC. RESULTS: Liver and peritoneal metastases exhibited distinct properties in cancer cells and dynamics of tumor microenvironment phenotypes, supporting the notion that cancer cells and their local tumor microenvironments co-evolve at metastatic sites. Our study also revealed differential activation of cancer meta-programs across metastases. We observed evasion of cancer cell ferroptosis via GPX4 up-regulation during GAC progression. Conditional depletion of Gpx4 or pharmacologic inhibition of ferroptosis resistance significantly attenuated tumor growth and metastatic progression. In addition, ferroptosis-resensitizing treatments augmented the efficacy of chimeric antigen receptor T-cell therapy. CONCLUSIONS: This study represents the largest single-cell dataset of metastatic GACs to date. High-resolution mapping of the molecular and cellular dynamics of GAC metastasis has revealed a rationale for targeting ferroptosis defense in combination with chimeric antigen receptor T-cell therapy as a novel therapeutic strategy with potential immense clinical implications.

Epithelial SOX9 drives progression and metastases of gastric adenocarcinoma by promoting immunosuppressive tumour microenvironment.

OBJECTIVE: Many cancers engage embryonic genes for rapid growth and evading the immune system. SOX9 has been upregulated in many tumours, yet the role of SOX9 in mediating immunosuppressive tumour microenvironment is unclear. Here, we aim to dissect the role of SOX9-mediated cancer stemness attributes and immunosuppressive microenvironment in advanced gastric adenocarcinoma (GAC) for novel therapeutic discoveries. METHODS: Bulk RNAseq/scRNA-seq, patient-derived cells/models and extensive functional studies were used to identify the expression and functions of SOX9 and its target genes in vitro and in vivo. Immune responses were studied in PBMCs or CD45+ immune cells cocultured with tumour cells with SOX9high or knockout and the KP-Luc2 syngeneic models were used for efficacy of combinations. RESULTS: SOX9 is one of the most upregulated SOX genes in GAC and highly expressed in primary and metastatic tissues and associated with poor prognosis. Depletion of SOX9 in patient-derived GAC cells significantly decreased cancer stemness attributes, tumour formation and metastases and consistently increased CD8+ T cell responses when cocultured with PBMCs/CD45+ cells from GAC patients. RNA sequencing identified the leukaemia inhibitory factor (LIF) as the top secreted molecule regulated by SOX9 in tumour cells and was enriched in malignant ascites and mediated SOX9-induced M2 macrophage repolarisation and inhibited T cell function. CONCLUSION: Epithelial SOX9 is critical in suppressing CD8+ T cell responses and modified macrophage function in GAC through the paracrine LIF factor. Cotargeting LIF/LIFR and CSF1R has great potential in targeting SOX9-mediated cancer stemness, T cell immunosuppression and metastases suggesting the novel combination therapy against advanced GAC.

Clinically conserved genomic subtypes of gastric adenocarcinoma.

Gastric adenocarcinoma (GAC) is a lethal disease characterized by genomic and clinical heterogeneity. By integrating 8 previously established genomic signatures for GAC subtypes, we identified 6 clinically and molecularly distinct genomic consensus subtypes (CGSs). CGS1 have the poorest prognosis, very high stem cell characteristics, and high IGF1 expression, but low genomic alterations. CGS2 is enriched with canonical epithelial gene expression. CGS3 and CGS4 have high copy number alterations and low immune reactivity. However, CGS3 and CGS4 differ in that CGS3 has high HER2 activation, while CGS4 has high SALL4 and KRAS activation. CGS5 has the high mutation burden and moderately high immune reactivity that are characteristic of microsatellite instable tumors. Most CGS6 tumors are positive for Epstein Barr virus and show extremely high levels of methylation and high immune reactivity. In a systematic analysis of genomic and proteomic data, we estimated the potential response rate of each consensus subtype to standard and experimental treatments such as radiation therapy, targeted therapy, and immunotherapy. Interestingly, CGS3 was significantly associated with a benefit from chemoradiation therapy owing to its high basal level of ferroptosis. In addition, we also identified potential therapeutic targets for each consensus subtype. Thus, the consensus subtypes produced a robust classification and provide for additional characterizations for subtype-based customized interventions.

Loss of ARID1A activates mTOR signaling and SOX9 in gastric adenocarcinoma-rationale for targeting ARID1A deficiency.

BACKGROUND: Gastric adenocarcinoma (GAC) is a lethal disease with limited therapeutic options. Genetic alterations in chromatin remodelling gene AT-rich interactive domain 1A (ARID1A) and mTOR pathway activation occur frequently in GAC. Targeting the mechanistic target of rapamycin (mTOR) pathway in unselected patients has failed to show survival benefit. A deeper understanding of GAC might identify a subset that can benefit from mTOR inhibition. METHODS: Genomic alterations in ARID1A were analysed in GAC. Mouse gastric epithelial cells from CK19-Cre-Arid1Afl/fl and wild-type mice were used to determine the activation of oncogenic genes due to loss of Arid1A. Functional studies were performed to determine the significance of loss of ARID1A and the sensitivity of ARID1A-deficient cancer cells to mTOR inhibition in GAC. RESULTS: More than 30% of GAC cases had alterations (mutations or deletions) of ARID1A and ARID1A expression was negatively associated with phosphorylation of S6 and SOX9 in GAC tissues and patient-derived xenografts (PDXs). Activation of mTOR signalling (increased pS6) and SOX9 nuclear expression were strongly increased in Arid1A-/- mouse gastric tissues which could be curtailed by RAD001, an mTOR inhibitor. Knockdown of ARID1A in GAC cell lines increased pS6 and nuclear SOX9 and increased sensitivity to an mTOR inhibitor which was further amplified by its combination with fluorouracil both in vitro and in vivo in PDXs. CONCLUSIONS: The loss of ARID1A activates pS6 and SOX9 in GAC, which can be effectively targeted by an mTOR inhibitor. Therefore, our studies suggest a new therapeutic strategy of clinically targeting the mTOR pathway in patients with GAC with ARID1A deficiency.

Effect of oxygen partial pressure on the performance of homojunction amorphous In-Ga-Zn-O thin-film transistors.

In this study, the homojunction thin-film transistors (TFTs) with amorphous indium gallium zinc oxide (a-IGZO) as active channel layers and source/drain electrodes were fabricated by RF magnetron sputtering. The effect of oxygen partial pressure on the phase, microstructure, optical and electrical properties of IGZO thin films was investigated. The results showed that amorphous IGZO thin films always exhibit a high transmittance above 90% and wide band gaps of around 3.9 eV. The resistivity increases as the IGZO thin films are deposited at a higher oxygen partial pressure due to the depletion of oxygen vacancies. In addition, the electrical behaviors in homojunction IGZO TFTs were analyzed. When the active channel layers were deposited with an oxygen partial pressure of 1.96%, the homojunction IGZO TFTs exhibited optimal transfer and output characteristics with a field-effect mobility of 13.68 cm2V-1s-1. Its sub-threshold swing, threshold voltage and on/off ratio are 0.6 V/decade, 0.61 V and 107, respectively.

Targeting cancer stem cells with a pan-BCL-2 inhibitor in preclinical and clinical settings in patients with gastroesophageal carcinoma.

OBJECTIVE: Gastro-oesophageal cancers (GEC) are resistant to therapy and lead to poor prognosis. The cancer stem cells (CSCs) and antiapoptotic pathways often confer therapy resistance. We sought to elucidate the antitumour action of a BCL-2 inhibitor, AT101 in GEC in vitro, in vivo and in a clinical trial. METHODS: Extensive preclinical studies in vitro and in vivo were carried out to establish the mechanism action of AT101 on targeting CSCs and antiapoptotic proteins. A pilot clinical trial in patients with GEC was completed with AT-101 added to standard chemoradiation. RESULTS: Overexpression of BCL-2 and MCL-1 was noted in gastric cancer tissues (GC). AT-101 induced apoptosis, reduced proliferation and tumour sphere formation in MCL-1/BCL-2 high GC cells. Interestingly, AT101 dramatically downregulated genes (YAP-1/Sox9) that control CSCs in GEC cell lines regardless of BCL-2/MCL-1 expression. Addition of docetaxel to AT-101 amplified its antiproliferation and induced apoptosis effects. In vivo studies confirmed the combination of AT101 and docetaxel demonstrated stronger antitumour activity accompanied with significant decrease of CSCs biomarkers (YAP1/SOX9). In a pilot clinical trial, 13 patients with oesophageal cancer (EC) received AT101 orally concurrently with chemoradiation. We observed dramatic clinical complete responses and encouraging overall survival in these patients. Clinical specimen analyses revealed that AT-101 dramatically reduced the expression of CSCs genes in treated EC specimens indicating antitumour activity of AT101 relies more on its anti-CSCs activity. CONCLUSIONS: Our preclinical and clinical data suggest that AT-101 overcomes resistance by targeting CSCs pathways suggesting a novel mechanism of action of AT101 in patients with GEC.

YAP1 mediates gastric adenocarcinoma peritoneal metastases that are attenuated by YAP1 inhibition.

OBJECTIVE: Peritoneal carcinomatosis (PC; malignant ascites or implants) occurs in approximately 45% of advanced gastric adenocarcinoma (GAC) patients and associated with a poor survival. The molecular events leading to PC are unknown. The yes-associated protein 1 (YAP1) oncogene has emerged in many tumour types, but its clinical significance in PC is unclear. Here, we investigated the role of YAP1 in PC and its potential as a therapeutic target. METHODS: Patient-derived PC cells, patient-derived xenograft (PDX) and patient-derived orthotopic (PDO) models were used to study the function of YAP1 in vitro and in vivo. Immunofluorescence and immunohistochemical staining, RNA sequencing (RNA-Seq) and single-cell RNA-Seq (sc-RNA-Seq) were used to elucidate the expression of YAP1 and PC cell heterogeneity. LentiCRISPR/Cas9 knockout of YAP1 and a YAP1 inhibitor were used to dissect its role in PC metastases. RESULTS: YAP1 was highly upregulated in PC tumour cells, conferred cancer stem cell (CSC) properties and appeared to be a metastatic driver. Dual staining of YAP1/EpCAM and sc-RNA-Seq revealed that PC tumour cells were highly heterogeneous, YAP1high PC cells had CSC-like properties and easily formed PDX/PDO tumours but also formed PC in mice, while genetic knockout YAP1 significantly slowed tumour growth and eliminated PC in PDO model. Additionally, pharmacologic inhibition of YAP1 specifically reduced CSC-like properties and suppressed tumour growth in YAP1high PC cells especially in combination with cytotoxics in vivo PDX model. CONCLUSIONS: YAP1 is essential for PC that is attenuated by YAP1 inhibition. Our data provide a strong rationale to target YAP1 in clinic for GAC patients with PC.

Integrated genomic profiling and modelling for risk stratification in patients with advanced oesophagogastric adenocarcinoma.

OBJECTIVE: Prognosis of patients with advanced oesophagogastric adenocarcinoma (mEGAC) is poor and molecular determinants of shorter or longer overall survivors are lacking. Our objective was to identify molecular features and develop a prognostic model by profiling the genomic features of patients with mEGAC with widely varying outcomes. DESIGN: We profiled 40 untreated mEGACs (20 shorter survivors <13 months and 20 longer survivors >36 months) with whole-exome sequencing (WES) and RNA sequencing and performed an integrated analysis of exome, transcriptome, immune profile and pathological phenotypes to identify the molecular determinants, developing an integrated model for prognosis and comparison with The Cancer Genome Atlas (TCGA) cohorts. RESULTS: KMT2C alterations were exclusively observed in shorter survivors together with high level of intratumour heterogeneity and complex clonal architectures, whereas the APOBEC mutational signatures were significantly enriched in longer survivors. Notably, the loss of heterozygosity in chromosome 4 (Chr4) was associated with shorter survival and 'cold' immune phenotype characterised by decreased B, CD8, natural killer cells and interferon-gamma responses. Unsupervised transcriptomic clustering revealed a shorter survivor subtype with distinct expression features (eg, upregulated druggable targets JAK2, MAP3K13 and MECOM). An integrated model was then built based on clinical variables and the identified molecular determinants, which significantly segregated shorter and longer survivors. All the above features and the integrated model have been validated independently in multiple TCGA cohorts. CONCLUSION: This study discovered novel molecular features prognosticating overall survival in patients with mEGAC and identified potential novel targets in shorter survivors.

College of American Pathologists Tumor Regression Grading System for Long-Term Outcome in Patients with Locally Advanced Rectal Cancer.

BACKGROUND: The National Comprehensive Cancer Network's Rectal Cancer Guideline Panel recommends American Joint Committee of Cancer and College of American Pathologists (AJCC/CAP) tumor regression grading (TRG) system to evaluate pathologic response to neoadjuvant chemoradiotherapy for locally advanced rectal cancer (LARC). Yet, the clinical significance of the AJCC/CAP TRG system has not been fully defined. MATERIALS AND METHODS: This was a multicenter, retrospectively recruited, and prospectively maintained cohort study. Patients with LARC from one institution formed the discovery set, and cases from external independent institutions formed a validation set to verify the findings from discovery set. Overall survival (OS), disease-free survival (DFS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) were assessed by Kaplan-Meier analysis, log-rank test, and Cox regression model. RESULTS: The discovery set (940 cases) found, and the validation set (2,156 cases) further confirmed, that inferior AJCC/CAP TRG categories were closely /ccorrelated with unfavorable survival (OS, DFS, LRFS, and DMFS) and higher risk of disease progression (death, accumulative relapse, local recurrence, and distant metastasis) (all p < .05). Significantly, pairwise comparison revealed that any two of four TRG categories had the distinguished survival and risk of disease progression. After propensity score matching, AJCC/CAP TRG0 category (pathological complete response) patients treated with or without adjuvant chemotherapy displayed similar survival of OS, DFS, LRFS, and DMFS (all p > .05). For AJCC/CAP TRG1-3 cases, adjuvant chemotherapy treatment significantly improved 3-year OS (90.2% vs. 84.6%, p < .001). Multivariate analysis demonstrated the AJCC/CAP TRG system was an independent prognostic surrogate. CONCLUSION: AJCC/CAP TRG system, an accurate prognostic surrogate, appears ideal for further strategizing adjuvant chemotherapy for LARC. IMPLICATIONS FOR PRACTICE: The National Comprehensive Cancer Network recommends the American Joint Committee of Cancer and College of American Pathologists (AJCC/CAP) tumor regression grading (TRG) four-category system to evaluate the pathologic response to neoadjuvant treatment for patients with locally advanced rectal cancer; however, the clinical significance of the AJCC/CAP TRG system has not yet been clearly addressed. This study found, for the first time, that any two of four AJCC/CAP TRG categories had the distinguished long-term survival outcome. Importantly, adjuvant chemotherapy may improve the 3-year overall survival for AJCC/CAP TRG1-3 category patients but not for AJCC/CAP TRG0 category patients. Thus, AJCC/CAP TRG system, an accurate surrogate of long-term survival outcome, is useful in guiding adjuvant chemotherapy management for rectal cancer.

The Long Noncoding RNA CCAT2 Induces Chromosomal Instability Through BOP1-AURKB Signaling.

BACKGROUND & AIMS: Chromosomal instability (CIN) is a carcinogenesis event that promotes metastasis and resistance to therapy by unclear mechanisms. Expression of the colon cancer-associated transcript 2 gene (CCAT2), which encodes a long noncoding RNA (lncRNA), associates with CIN, but little is known about how CCAT2 lncRNA regulates this cancer enabling characteristic. METHODS: We performed cytogenetic analysis of colorectal cancer (CRC) cell lines (HCT116, KM12C/SM, and HT29) overexpressing CCAT2 and colon organoids from C57BL/6N mice with the CCAT2 transgene and without (controls). CRC cells were also analyzed by immunofluorescence microscopy, γ-H2AX, and senescence assays. CCAT2 transgene and control mice were given azoxymethane and dextran sulfate sodium to induce colon tumors. We performed gene expression array and mass spectrometry to detect downstream targets of CCAT2 lncRNA. We characterized interactions between CCAT2 with downstream proteins using MS2 pull-down, RNA immunoprecipitation, and selective 2'-hydroxyl acylation analyzed by primer extension analyses. Downstream proteins were overexpressed in CRC cells and analyzed for CIN. Gene expression levels were measured in CRC and non-tumor tissues from 5 cohorts, comprising more than 900 patients. RESULTS: High expression of CCAT2 induced CIN in CRC cell lines and increased resistance to 5-fluorouracil and oxaliplatin. Mice that expressed the CCAT2 transgene developed chromosome abnormalities, and colon organoids derived from crypt cells of these mice had a higher percentage of chromosome abnormalities compared with organoids from control mice. The transgenic mice given azoxymethane and dextran sulfate sodium developed more and larger colon polyps than control mice given these agents. Microarray analysis and mass spectrometry indicated that expression of CCAT2 increased expression of genes involved in ribosome biogenesis and protein synthesis. CCAT2 lncRNA interacted directly with and stabilized BOP1 ribosomal biogenesis factor (BOP1). CCAT2 also increased expression of MYC, which activated expression of BOP1. Overexpression of BOP1 in CRC cell lines resulted in chromosomal missegregation errors, and increased colony formation, and invasiveness, whereas BOP1 knockdown reduced viability. BOP1 promoted CIN by increasing the active form of aurora kinase B, which regulates chromosomal segregation. BOP1 was overexpressed in polyp tissues from CCAT2 transgenic mice compared with healthy tissue. CCAT2 lncRNA and BOP1 mRNA or protein were all increased in microsatellite stable tumors (characterized by CIN), but not in tumors with microsatellite instability compared with nontumor tissues. Increased levels of CCAT2 lncRNA and BOP1 mRNA correlated with each other and with shorter survival times of patients. CONCLUSIONS: We found that overexpression of CCAT2 in colon cells promotes CIN and carcinogenesis by stabilizing and inducing expression of BOP1 an activator of aurora kinase B. Strategies to target this pathway might be developed for treatment of patients with microsatellite stable colorectal tumors.

A Phase II Trial of Cytoreduction, Gastrectomy, and Hyperthermic Intraperitoneal Perfusion with Chemotherapy for Patients with Gastric Cancer and Carcinomatosis or Positive Cytology.

BACKGROUND: Current national guidelines do not include hyperthermic intraperitoneal chemoperfusion (HIPEC) as treatment for gastric cancer, and there are no completed clinical trials of cytoreduction, gastrectomy, and HIPEC from the US. METHODS: Patients with gastric adenocarcinoma and positive peritoneal cytology or carcinomatosis who had completed systemic chemotherapy and laparoscopic HIPEC underwent cytoreduction, gastrectomy, and HIPEC with 30 mg mitomycin C and 200 mg cisplatin. The primary endpoint was overall survival (OS), with a secondary endpoint of postoperative complications (NCT02891447). RESULTS: We enrolled 20 patients from September 2016 to March 2019. Six patients had positive cytology only and 14 had carcinomatosis. All patients were treated with systemic chemotherapy with a median of eight cycles (range 5-11 cycles) and at least one laparoscopic HIPEC. The median peritoneal carcinomatosis index at cytoreduction/gastrectomy/HIPEC was 2 (range 0-13). After surgery, the 90-day morbidity and mortality rates were 70% and 0%, respectively. Median length of hospital stay was 13 days (range 7-23 days); median follow-up was 33.5 months; median OS from the date of diagnosis of metastatic disease was 24.2 months; and median OS from the date of cytoreduction, gastrectomy, and HIPEC was 16.1 months. 1-, 2-, and 3-year OS rates from the diagnosis of metastatic disease were 90%, 50%, and 28%, respectively. CONCLUSIONS: Survival rates for patients with gastric adenocarcinoma and peritoneal disease treated with cytoreduction, gastrectomy, and HIPEC are encouraging; our early results are similar to those of recent prospective registry studies. Multi-institutional and cooperative group trials should be supported to confirm survival and safety outcomes.

Drug resistance and Cancer stem cells.

Therapy resistance is a major problem when treating cancer patients as cancer cells develop mechanisms that counteract the effect of therapeutic compounds, leading to fit and more aggressive clones that contribute to poor prognosis. Therapy resistance can be both intrinsic and/or acquired. These are multifactorial events, and some are related to factors including adaptations in cancer stem cells (CSCs), epithelial-mesenchymal transition (EMT), deregulation of key signaling pathways, drug efflux through ABC transporters, acquired mutations, evading apoptosis, and activation of DNA damage response among others. Among these factors, CSCs represent the major source of therapy resistance. CSCs are a subset of tumor cells that are capable of self-renewal and multilineage progenitor expansion that are known to be intrinsically resistant to anticancer treatments. Multiple clones of CSCs pre-exist, and some can adopt and expand easily to changes in the tumor microenvironment (TME) and/or in response to radio- and chemotherapy. A combination of both intrinsic and extrinsic factors contributes to CSC-mediated therapy resistance. In this review, we will focus on CSCs and therapy resistance as well as suggest strategies to eliminate CSCs and, therefore, overcome resistance. Video abstract.

Influence of annealing temperature on the optoelectronic properties of ITZO thin films.

In this work, the electrical conductivity and optical transparency of the In-Sn-Zn-O (ITZO) films annealed at different temperatures were investigated. The results show that the ITZO films transformed from amorphous phase to crystalline phase after annealed in the air. The transmittance of the films improves significantly and all exceed 88%. Meanwhile, the annealed ITZO films exhibit a significant enhancement in conductivity. In particular, ITZO film annealed at 650 °C has high electrical conductivity (∼4.94 × 102S cm-1) and an excellent figure of merit (∼5.94 × 10-4Ω-1). Moreover, ITZO thin film transistors were prepared and their performance was tested. After annealing, the high electrical properties of the active layer make the gate regulation ability of the thin film transistors degrade. The annealed films with excellent optoelectronic properties can be applied to transparent electrodes.

Multiplex profiling of peritoneal metastases from gastric adenocarcinoma identified novel targets and molecular subtypes that predict treatment response.

OBJECTIVE: Peritoneal carcinomatosis (PC) occurs frequently in patients with gastric adenocarcinoma (GAC) and confers a poor prognosis. Multiplex profiling of primary GACs has been insightful but the underpinnings of PC's development/progression remain largely unknown. We characterised exome/transcriptome/immune landscapes of PC cells from patients with GAC aiming to identify novel therapeutic targets. DESIGN: We performed whole-exome sequencing (WES) and whole transcriptome sequencing (RNA-seq) on 44 PC specimens (43 patients with PC) including an integrative analysis of WES, RNA-seq, immune profile, clinical and pathological phenotypes to dissect the molecular pathogenesis, identifying actionable targets and/or biomarkers and comparison with TCGA primary GACs. RESULTS: We identified distinct alterations in PC versus primary GACs, such as more frequent CDH1 and TAF1 mutations, 6q loss and chr19 gain. Alterations associated with aggressive PC phenotypes emerged with increased mutations in TP53, CDH1, TAF1 and KMT2C, higher level of 'clock-like' mutational signature, increase in whole-genome doublings, chromosomal instability (particularly, copy number losses), reprogrammed microenvironment, enriched cell cycle pathways, MYC activation and impaired immune response. Integrated analysis identified two main molecular subtypes: 'mesenchymal-like' and 'epithelial-like' with discriminating response to chemotherapy (31% vs 71%). Patients with the less responsive 'mesenchymal-like' subtype had high expression of immune checkpoint T-Cell Immunoglobulin And Mucin Domain-Containing Protein 3 (TIM-3), its ligand galectin-9, V-domain Ig suppressor of T cell activation (VISTA) and transforming growth factor-ß as potential therapeutic immune targets. CONCLUSIONS: We have uncovered the unique mutational landscape, copy number alteration and gene expression profile of PC cells and defined PC molecular subtypes, which correlated with PC therapy resistance/response. Novel targets and immune checkpoint proteins have been identified with a potential to be translated into clinics.

Factors Associated with Resection and Survival After Laparoscopic HIPEC for Peritoneal Gastric Cancer Metastasis.

PURPOSE: Although laparoscopic hyperthermic intraperitoneal chemotherapy (LS-HIPEC) has been proven safe in patients with gastric adenocarcinoma and carcinomatosis or positive cytology, patient selection criteria remain unclear. Thus, we perform a retrospective analysis to identify factors associated with improved survival and resection rates. PATIENTS AND METHODS: Data for all patients undergoing LS-HIPEC for stage IV gastric adenocarcinoma between June 2014 and November 2018 were collected prospectively and analyzed for associations with survival and resection using uni- and multivariate logistic regression, Cox proportional hazards models, and Kaplan-Meier survival functions. RESULTS: Of 70 patients who underwent LS-HIPEC, 43 (61%) received two drugs (mitomycin C and cisplatin), and 27 (39%) received three drugs (mitomycin C, cisplatin, and paclitaxel). The two groups' demographic and oncologic differences were not significant, although the three-drug group had a significantly lower rate of radiation therapy use (58% vs. 15%; p < 0.01). Univariate analysis revealed that poor differentiation [Cox hazard ratio (HR) 2.75; 95% confidence interval (CI) 1.34-5.63; p < 0.01], gross carcinomatosis (HR 3.10; 95% CI 1.52-6.30; p = 0.03), and ascites (HR 3.43; 95% CI 1.88-6.26; p < 0.01) were associated with shorter median survival. Gastrectomy was associated with improved overall survival (HR 0.32; 95% CI 0.15-0.70; p < 0.01). The resection rate of the 45 patients without ascites (38%) was significantly higher than that of the 25 patients with ascites (0%; p < 0.01). CONCLUSIONS: Our findings identify ascites as a significant prognostic factor for gastric cancer patients with peritoneal metastases undergoing LS-HIPEC. Our findings can be used to help identify patients who are unlikely to proceed to resection after LS-HIPEC and are good candidates for novel therapeutic approaches or clinical trials.

Phase I Trial of Hyperthermic Intraperitoneal Chemoperfusion (HIPEC) with Cisplatin, Mitomycin, and Paclitaxel in Patients with Gastric Adenocarcinoma and Associated Carcinomatosis or Positive Cytology.

BACKGROUND: The purpose of this phase I trial is to evaluate the safety and toxicity of laparoscopic hyperthermic intraperitoneal perfusion with chemotherapy (HIPEC), combining mitomycin, cisplatin, and paclitaxel for patients with gastric cancer metastatic to the peritoneum. PATIENTS AND METHODS: A Bayesian optimal interval design was used to prospectively identify the safety and tolerability of escalating doses of paclitaxel in combination with flat doses of mitomycin (30 mg) and cisplatin (200 mg) during laparoscopic HIPEC. The primary objective is to define the maximum tolerated dose. Secondary endpoints include surgical complications and overall survival (OS). RESULTS: A total of 27 patients were treated between 11/2017 and 11/2018. No dose-limiting toxicities were observed. Treatment-related grade 1-2 toxicities were leukopenia (11%), oral dysesthesia (4%), arthralgia (4%), and diarrhea (4%). Treatment-related grade 3-4 toxicities included leukopenia (4%) and neutropenia (4%). The maximum dose for paclitaxel was 60 mg/m2. Rates of Clavien-Dindo surgical complications were grade I 96% (all electrolyte deficiencies requiring replacement), II 4%, III 0%, IV 0%, and V 4%. The median follow-up time was 15 months. One- and 2-year OS rates from date of metastatic disease were 73.9% and 58.1%, respectively. CONCLUSIONS: Laparoscopic HIPEC with mitomycin, cisplatin, and paclitaxel may be safely used at intraperitoneal doses of 30 mg, 200 mg, and 60 mg/m2, respectively. Although electrolyte abnormalities were common, systemic toxicity was low. Survival rates were promising, supporting further research into intraperitoneal therapy for stage IV gastric cancer.

LncRNA PVT1 up-regulation is a poor prognosticator and serves as a therapeutic target in esophageal adenocarcinoma.

BACKGROUND: PVT1 has emerged as an oncogene in many tumor types. However, its role in Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) is unknown. The aim of this study was to assess the role of PVT1 in BE/EAC progression and uncover its therapeutic value against EAC. METHODS: PVT1 expression was assessed by qPCR in normal, BE, and EAC tissues and statistical analysis was performed to determine the association of PVT1 expression and EAC (stage, metastases, and survival). PVT1 antisense oligonucleotides (ASOs) were tested for their antitumor activity in vitro and in vivo. RESULTS: PVT1 expression was up-regulated in EACs compared with paired BEs, and normal esophageal tissues. High expression of PVT1 was associated with poor differentiation, lymph node metastases, and shorter survival. Effective knockdown of PVT1 in EAC cells using PVT1 ASOs resulted in decreased cell proliferation, invasion, colony formation, tumor sphere formation, and reduced proportion of ALDH1A1+ cells. Mechanistically, we discovered mutual regulation of PVT1 and YAP1 in EAC cells. Inhibition of PVT1 by PVT1 ASOs suppressed YAP1 expression through increased phosphor-LATS1and phosphor-YAP1 while knockout of YAP1 in EAC cells significantly suppressed PVT1 levels indicating a positive regulation of PVT1 by YAP1. Most importantly, we found that targeting both PVT1 and YAP1 using their specific ASOs led to better antitumor activity in vitro and in vivo. CONCLUSIONS: Our results provide strong evidence that PVT1 confers an aggressive phenotype to EAC and is a poor prognosticator. Combined targeting of PVT1 and YAP1 provided the highest therapeutic index and represents a novel therapeutic strategy.

Galectin-3 Mediates Tumor Cell-Stroma Interactions by Activating Pancreatic Stellate Cells to Produce Cytokines via Integrin Signaling.

BACKGROUND & AIMS: Pancreatic ductal adenocarcinoma (PDAC) is characterized by activated pancreatic stellate cells (PSCs), abundance of extracellular matrix (ECM), and production of cytokines and chemokines. Galectin 3 (GAL3), a ß-galactoside-specific lectin, contributes to PDAC development but its effects on the stroma and cytokine production are unclear. METHODS: The effect of recombinant human GAL3 (rGAL3) on activation of PSCs, production of cytokines, and ECM proteins was determined by proliferation, invasion, cytokine array, and quantitative polymerase chain reaction. We assessed co-cultures of PDAC cells with GAL3 genetic alterations with PSCs. Production of interleukin 8 (IL8) and activities of nuclear factor (NF)-κB were determined by enzyme-linked immunosorbent assay and luciferase reporter analyses. We studied the effects of inhibitors of NF-κB and integrin-linked kinase (ILK) on pathways activated by rGAL3. RESULTS: In analyses of the Gene Expression Omnibus database and our dataset, we observed higher levels of GAL3, IL8, and other cytokines in PDAC than in nontumor tissues. Production of IL8, granulocyte-macrophage colony-stimulating factor, chemokine ligand 1, and C-C motif chemokine ligand 2 increased in PSCs exposed to rGAL3 compared with controls. Culture of PSCs with PDAC cells that express different levels of GAL3 resulted in proliferation and invasion of PSCs that increased with level of GAL3. GAL3 stimulated transcription of IL8 through integrin subunit beta 1 (ITGB1) on PSCs, which activates NF-κB through ILK. Inhibitors of ILK or NF-κB or a neutralizing antibody against ITGB1 blocked transcription and production of IL8 from PSCs induced by rGAL3. The GAL3 inhibitor significantly reduced growth and metastases of orthotopic tumors that formed from PDAC and PSC cells co-implanted in mice. CONCLUSION: GAL3 activates PSC cells to produce inflammatory cytokines via ITGB1signaling to ILK and activation of NF-κB. Inhibition of this pathway reduced growth and metastases of pancreatic orthotopic tumors in mice.

The role of hedgehog signaling in gastric cancer: molecular mechanisms, clinical potential, and perspective.

Patients with advanced gastric cancer usually have a poor prognosis and limited therapeutic options. Overcoming this challenge requires novel targets and effective drugs. The Hedgehog (Hh) signaling pathway plays a crucial role in the development of the gastrointestinal tract and maintenance of the physiologic function of the stomach. Aberrantly activated Hh signaling is implicated in carcinogenesis as well as maintenance of cancer stem cells. Somatic mutations in the components of Hh signaling (PTCH1 and SMO) have been shown to be a major cause of basal cell carcinoma, and dozens of Hh inhibitors have been developed. To date, two inhibitors (GDC-0449 and LDE225) have been approved by the U.S. Food and Drug Administration to treat basal cell carcinoma and medulloblastoma. Here, we review the role of the Hh signaling in the carcinogenesis and progression of gastric cancer and summarize recent findings on Hh inhibitors in gastric cancer. Hedgehog signaling is often aberrantly activated and plays an important role during inflammation and carcinogenesis of gastric epithelial cells. Further study of the precise mechanisms of Hh signaling in this disease is needed for the validation of therapeutic targets and evaluation of the clinical utility of Hh inhibitors for gastric cancer.