Analysis of circulating tumor DNA identifies distinct therapeutic response to intraperitoneal and intravenous paclitaxel plus S-1 in gastric cancer patients with peritoneal metastasis.

Background: Circulating tumor DNA (ctDNA) is a promising technique for predicting curative effects and monitoring tumor recurrence. The utility of ctDNA for gastric cancer with peritoneal dissemination remains elusive. Objectives: To assess the feasibility of ctDNA in predicting tumor response to chemotherapy in gastric cancer with peritoneal dissemination. Design: This was a prospective study. Methods: We enrolled 30 patients with gastric cancer peritoneal metastasis, treated with intraperitoneal and intravenous paclitaxel plus S-1. Peripheral blood samples of patients were prospectively collected at baseline, after treatment initiation accompanied by computed tomography scan and disease progression. Mutational profiles from ctDNA were analyzed to evaluate its association with chemotherapeutic response. Results: Tumor protein 53 (TP53) was the most frequently altered gene at baseline blood samples. Although baseline TP53 mutation was not related to therapeutic response, patients with TP53 mutation had worse progression-free survival (PFS) and overall survival (OS). Additionally, baseline ctDNA content fraction (CCF) was found to be significantly lower in responders than non-responders. Meanwhile, patients with high CCF had a trend of worse PFS and OS. Combining TP53 alteration and CCF, the prognosis of TP53-wt patients could be further stratified. Patients with CCF-low_TP53-wt had markedly longer survival than those with CCF-high_TP53-wt. Conclusion: Our study highlighted the significance of ctDNA in predicting potential clinical outcomes in gastric cancer patients during chemotherapy. Trial registration: ChiCTR-IIR-16009802 (Chinese Clinical Trial Registry).

Value of 68Ga-FAPI-04 and 18F-FDG PET/CT in Early Prediction of Pathologic Response to Neoadjuvant Chemotherapy in Locally Advanced Gastric Cancer.

This prospective study investigated whether PET parameters from 18F-FDG and 68Ga-fibroblast activation protein inhibitor (FAPI)-04 PET/CT can predict a pathologic response to neoadjuvant chemotherapy (NAC) early in patients with locally advanced gastric cancer (LAGC). Methods: The study included 28 patients with LAGC who underwent 18F-FDG PET/CT and 68Ga-FAPI-04 PET/CT at baseline and after 1 cycle of NAC. PET parameters including SUV and tumor-to-background ratio (TBR), as well as the change rate of SUV and TBR, were recorded. Patients were classified as major or minor pathologic responders according to postoperative pathology findings. We compared the PET parameters between the 2 pathologic response groups and different treatment regimens and analyzed their predictive performance for tumor pathologic response. Results: Major pathologic responders had significantly lower 68Ga-FAPI change rates (percentage SUVmax [%SUVmax], percentage SUVpeak [%SUVpeak], and percentage TBR [%TBR]) than minor pathologic responders. Among the PET parameters, 68Ga-FAPI %SUVmax (area under the curve, 0.856; P = 0.009), %SUVpeak (area under the curve, 0.811; P = 0.022), and %TBR (area under the curve, 0.864; P = 0.007) were significant parameters for early prediction of pathologic response to NAC in LAGC; they had the same predictive accuracy of 89.29%, with the thresholds of decrease to at least 52.43%, 60.46%, and 52.96%, respectively. In addition, 68Ga-FAPI %SUVmax and %TBR showed significant differences between the different treatment regimens. Conclusion: In this preliminary study, 68Ga-FAPI-04 PET change rate parameters were preferable to 18F-FDG in predicting pathologic response to NAC at an early stage in LAGC. 68Ga-FAPI %SUVmax and %TBR may be better predictors of therapeutic response between different treatment regimens. These findings may help optimize the treatment for patients with LAGC.

The efficacy of neoadjuvant chemotherapy is different for type 4 and large type 3 gastric cancer.

BACKGROUND: In the JCOG0501 study, neoadjuvant chemotherapy (NAC) failed to demonstrate survival benefits for type 4 and large type 3 gastric cancer (GC). The prognosis of these patients is still poor. We conducted this study to explore the value of NAC with non-SP regimens for type 4 and large type 3 â€‹GC in the Chinese population. METHODS: We retrospectively collected data from our electronic medical record system. Patients with large type 3 or type 4 â€‹GC who underwent D2 gastrectomy and AC were included. Patients were divided into two groups based on whether they received NAC: the CSC (NAC â€‹+ â€‹surgery â€‹+ â€‹AC) and SC (surgery â€‹+ â€‹AC) groups. The survival and perioperative outcomes for large type 3 or type 4 â€‹GC were analyzed between the CSC and SC groups, separately. RESULTS: Between May 2009 and December 2018, 189 patients were reviewed. Among large type 3 â€‹GC, the 5-year overall survival (OS) rates for patients in the CSC and SC groups were 54.4 â€‹% and 28.0 â€‹%, respectively (P â€‹= â€‹0.0008). Among type 4 â€‹GC, the 5-year OS rates for patients in the CSC and SC groups were 15.8 â€‹% and 24.8 â€‹%, respectively (P â€‹> â€‹0.05). CONCLUSIONS: This study showed NAC can improve the prognosis of large type 3 â€‹GC. However, NAC did not demonstrate significant survival advantages for type 4 â€‹GC.

Oncological outcomes of conversion therapy in gastric cancer patients with peritoneal metastasis: a large-scale retrospective cohort study.

BACKGROUND: Data on the long-term oncological outcomes of patients who undergo conversion surgery (CS) in gastric cancer (GC) patients with peritoneal metastasis (PM) are limited. METHODS: GC patients with PM who received intraperitoneal (ip) and systemic chemotherapy between April 2015 and January 2021 were enrolled. Multivariate analysis was performed to identify risk factors associated with survival. Clinicopathological and survival outcomes were compared between those with CS and those without CS (NCS). The paclitaxel (PTX) plus tegafur-gimeracil-oteracil potassium capsules (S-1) (PS) + ip PTX and oxaliplatin plus S-1 (SOX) + ip PTX groups were matched in a 1:1 ratio using propensity score matching. Oncological and survival data were collected and analyzed. RESULTS: A total of 540 patients who received ip chemotherapy via subcutaneous port and systemic chemotherapy were analyzed and 268 patients were enrolled, including 113 who underwent CS and 155 who did not. Overall survival (OS) were 27.0 months and 11.8 months in the CS and NCS groups (P < 0.0001), respectively. R0 resection was an independent prognostic factor for patients who underwent CS. The OS of patients with or without ovariectomy was 21.3 or 12.0 months (P < 0.0001). No difference of clinicopathological and survival outcomes was found between the PS + ip PTX and SOX + ip PTX groups. CONCLUSION: Conversion therapy is safe and adverse events were manageable. CS improves the survival of GC patients with PM after ip and systemic chemotherapy. R0 is an important prognostic factor. Furthermore, outcomes are comparable between the PS + ip PTX and SOX + ip PTX groups.

Cancer-associated fibroblasts impair the cytotoxic function of NK cells in gastric cancer by inducing ferroptosis via iron regulation.

As the predominant immunosuppressive component within the tumor microenvironment (TME), cancer-associated fibroblasts (CAFs) inhibit Natural Killer cell (NK cell) activity to promote tumor progression and immune escape; however, the mechanisms of cross-talk between CAFs and NK cells in gastric cancer (GC) remain poorly understood. In this study, we demonstrate that NK cell levels are inversely correlated with CAFs abundance in human GC. CAFs impair the anti-tumor capacity of NK cells by inducing ferroptosis, a cell death process characterized by the accumulation of iron-dependent lipid peroxides. CAFs induce ferroptosis in NK cells by promoting iron overload; conversely, decreased intracellular iron levels protect NK cells against CAF-induced ferroptosis. Mechanistically, CAFs increase the labile iron pool within NK cells via iron export into the TME, which is mediated by the upregulated expression of iron regulatory genes ferroportin1 and hephaestin in CAFs. Moreover, CAF-derived follistatin like protein 1(FSTL1) upregulates NCOA4 expression in NK cells via the DIP2A-P38 pathway, and NCOA4-mediated ferritinophagy is required for CAF-induced NK cell ferroptosis. In a human patient-derived organoid model, functional targeting of CAFs using a combination of deferoxamine and FSTL1-neutralizing antibody significantly alleviate CAF-induced NK cell ferroptosis and boost the cytotoxicity of NK cells against GC. This study demonstrates a novel mechanism of suppression of NK cell activity by CAFs in the TME and presents a potential therapeutic approach to augment the immune response against GC mediated by NK cells.

Androgen receptor promotes cell stemness via interacting with co-factor YAP1 in gastric cancer.

Cancer stem cells (CSCs) have been proposed to explain tumor relapse and chemoresistance in various types of cancers, and androgen receptor (AR) has been emerged as a potential regulator of stemness in cancers. However, the underlying mechanism of AR-regulated CSCs properties and chemoresistance in gastric cancer (GC) remains unknown. Here, we shown that AR is upregulated in GC tissues and correlates with poor survival rate and CSCs phenotypes of GC patients. According to our experimental data, overexpression of AR upregulated the expression of CSCs markers and this was consistent with the result concluded from data analysis that the expression of AR was positively correlated with CD44 in GC patients. In addition, AR overexpression obviously enhanced the tumor sphere formation ability and chemoresistance of GC cells in vitro. Whereas these effects were attenuated by inhibition of AR. These results were further validated in vivo that MGC-803 cells overexpressing AR had stronger properties to initiate gastric tumorigenesis than the control cells, and inhibition of AR increased the chemosensitivity of GC cells. Mechanically, AR upregulated CD44 expression by directly binding to its promoter region and Yes-associated protein 1 (YAP1) served as the co-factor of AR, which was demonstrated by the fact that the promoting effects of AR on GC cells stemness were partially counteracted by YAP1 knockdown. Thus, this study revealed that AR facilitates CSCs properties and chemoresistance of GC cells via forming complex with YAP1and indicates a potential therapeutic approach to GC patients.

BPTF Drives Gastric Cancer Resistance to EGFR Inhibitor by Epigenetically Regulating the C-MYC/PLCG1/Perk Axis.

Erlotinib, an EGFR tyrosine kinase inhibitor, is used for treating patients with cancer exhibiting EGFR overexpression or mutation. However, the response rate of erlotinib is low among patients with gastric cancer (GC). The findings of this study illustrated that the overexpression of bromodomain PHD finger transcription factor (BPTF) is partially responsible for erlotinib resistance in GC, and the combination of the BPTF inhibitor AU-1 with erlotinib synergistically inhibited tumor growth both in vivo and in vitro. AU-1 inhibited the epigenetic function of BPTF and decreased the transcriptional activity of c-MYC on PLCG1 by attenuating chromosome accessibility of the PLCG1 promoter region, thus decreasing the expression of p-PLCG1 and p-Erk and eventually improving the sensitivity of GC cells to erlotinib. In patient-derived xenograft (PDX) models, AU-1 monotherapy exhibited remarkable tumor-inhibiting activity and is synergistic anti-tumor effects when combined with erlotinib. Altogether, the findings illustrate that BPTF affects the responsiveness of GC to erlotinib by epigenetically regulating the c-MYC/PLCG1/pErk axis, and the combination of BPTF inhibitors and erlotinib is a viable therapeutic approach for GC.

A quick and reliable image-based AI algorithm for evaluating cellular senescence of gastric organoids.

OBJECTIVE: Organoids are a powerful tool with broad application prospects in biomedicine. Notably, they provide alternatives to animal models for testing potential drugs before clinical trials. However, the number of passages for which organoids maintain cellular vitality ex vivo remains unclear. METHODS: Herein, we constructed 55 gastric organoids from 35 individuals, serially passaged the organoids, and captured microscopic images for phenotypic evaluation. Senescence-associated ß-galactosidase (SA-ß-Gal), cell diameter in suspension, and gene expression reflecting cell cycle regulation were examined. The YOLOv3 object detection algorithm integrated with a convolutional block attention module (CBAM) was used to evaluate organoid vitality. RESULTS: SA-ß-Gal staining intensity; single-cell diameter; and expression of p15, p16, p21, CCNA2, CCNE2, and LMNB1 reflected the progression of aging in organoids during passaging. The CBAM-YOLOv3 algorithm precisely evaluated aging organoids on the basis of organoid average diameter, organoid number, and number × diameter, and the findings positively correlated with SA-ß-Gal staining and single-cell diameter. Organoids derived from normal gastric mucosa had limited passaging ability (passages 1-5), before aging, whereas tumor organoids showed unlimited passaging potential for more than 45 passages (511 days) without showing clear senescence. CONCLUSIONS: Given the lack of indicators for evaluating organoid growth status, we established a reliable approach for integrated analysis of phenotypic parameters that uses an artificial intelligence algorithm to indicate organoid vitality. This method enables precise evaluation of organoid status in biomedical studies and monitoring of living biobanks.

Circulating neutrophils activated by cancer cells and M2 macrophages promote gastric cancer progression during PD-1 antibody-based immunotherapy.

Aims: To analyze the correlation between the neutrophil-to-lymphocyte ratio (NLR) and prognosis of advanced gastric cancer (AGC) patients treated by PD-1 antibody-based therapy and to delineate molecular characteristics of circulating neutrophils by single-cell RNA sequencing (scRNA-seq). Methods: The clinicopathological information of 45 AGC patients receiving PD-1 antibody-based regimens at the Department of Oncology, Ruijin Hospital, was reviewed. Treatment outcomes including objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) were recorded. The correlation between NLR and efficacy of PD-1 antibody-based treatment was analyzed. Single-cell RNA sequencing (scRNA-seq) analysis was performed based on multisite biopsy samples from two AGC patients to explore the molecular characteristics of circulating neutrophils and their pro-tumor mechanisms. Tissue samples from 88 gastric cancer patients who underwent radial gastrectomy were collected for immunochemistry staining. Results: A high posttreatment NLR was associated with poor outcomes of AGC patients receiving PD-1 antibody-based regimens. scRNA-seq analysis showed that an increased number of circulating neutrophils were found in peripheral blood samples after treatment in which neutrophil cluster 1 (NE-1) was the major subcluster. NE-1 was featured with a neutrophil activation phenotype with the high expression of MMP9, S100A8, S100A9, PORK2, and TGF-ß1. NE-1 displayed an intermediate state in pseudotime trajectory analysis with gene function enrichment found in neutrophil activation, leukocyte chemotaxis, and negative regulation of MAP kinase activity. Cellular interaction analysis showed that the chemokine signaling pathway is the major interactional pathway of NE-1 between subclusters of malignant epithelial cells (EP-4) and M2 macrophages (M2-1 and M2-2). In turn, the MAPK signaling pathway and Jak-STAT signaling pathway of EP-4, including IL1B/IL1RAP, OSM/OSMR, and TGFB1/TGFBR2 axes, were identified as interacting pathways between EP-4 and NE-1. The high expression of OSMR in tumor cells was closely correlated with lymph node metastasis of gastric cancer. Conclusion: The posttreatment NLR could be a poor prognostic marker of AGC patients treated with immune checkpoint inhibitors (ICIs). Subclusters of circulating neutrophils activated by tumor cells and M2 macrophages could participate in gastric cancer progression through signaling interactions with tumor cells.

Sintilimab combined neoadjuvant intraperitoneal and systemic chemotherapy in gastric cancer with peritoneal metastasis.

Intraperitoneal chemotherapy combined with systemic chemotherapy is one of the therapeutic modalities currently used for the treatment of gastric cancer patients with peritoneal metastasis. This study was designed to evaluate the efficacy and safety of sintilimab plus S-1 combined intraperitoneal and intravenous paclitaxel. This is an open-label, single-center, phase II study including 36 gastric adenocarcinoma patients with peritoneal metastases diagnosed by laparoscopy. All enrolled patients received sintilimab, intraperitoneal and intravenous paclitaxel plus oral S-1 every 3 weeks. Conversion operation should be considered when a patient responds to the regimen and the peritoneal metastasis disappears. After gastrectomy, the protocol treatment is repeated until disease progression, unacceptable toxicity, investigator decision or patient withdrawal. The primary end point is the 1-year survival rate. Clinical Trial Registration: NCT05204173 (ClinicalTrials.gov).

Optimal postoperative surveillance strategies for cancer survivors with gastric neuroendocrine carcinoma based on individual risk: a multicenter real-world cohort study.

BACKGROUND: The best follow-up strategy for cancer survivors after treatment should balance the effectiveness and cost of disease detection while detecting recurrence as early as possible. Due to the low incidence of gastric neuroendocrine carcinoma and mixed adenoneuroendocrine carcinoma [G-(MA)NEC], high-level evidence-based follow-up strategies is limited. Currently, there is a lack of consensus among clinical practice guidelines regarding the appropriate follow-up strategies for patients with resectable G-(MA)NEC. MATERIALS AND METHODS: The study included patients diagnosed with G-(MA)NEC from 21 centers in China. The random forest survival model simulated the monthly probability of recurrence to establish an optimal surveillance schedule maximizing the power of detecting recurrence at each follow-up. The power and cost-effectiveness were compared with the National Comprehensive Cancer Network, European Neuroendocrine Tumor Society, and European Society for Medical Oncology Guidelines. RESULTS: A total of 801 patients with G-(MA)NEC were included. The patients were stratified into four distinct risk groups utilizing the modified TNM staging system. The study cohort comprised 106 (13.2%), 120 (15.0%), 379 (47.3%), and 196 cases (24.5%) for modified groups IIA, IIB, IIIA, and IIIB, respectively. Based on the monthly probability of disease recurrence, the authors established four distinct follow-up strategies for each risk group. The total number of follow-ups 5 years after surgery in the four groups was 12, 12, 13, and 13 times, respectively. The risk-based follow-up strategies demonstrated improved detection efficiency compared to existing clinical guidelines. Further Markov decision-analytic models verified that the risk-based follow-up strategies were better and more cost-effective than the control strategy recommended by the guidelines. CONCLUSIONS: This study developed four different monitoring strategies based on individualized risks for patients with G-(MA)NEC, which may improve the detection power at each visit and were more economical, effective. Even though our results are limited by the biases related to the retrospective study design, we believe that, in the absence of a randomized clinical trial, our findings should be considered when recommending follow-up strategies for G-(MA)NEC.

VPS35 promotes cell proliferation via EGFR recycling and enhances EGFR inhibitors response in gastric cancer.

BACKGROUND: Vacuolar protein sorting-associated protein 35 (VPS35) is a core component of the retromer complex which mediates intracellular protein transport. It is well known that dysfunctional VPS35 functions in the accumulation of pathogenic proteins. In our previous study, VPS35 was found to be a potential gene related to poor prognosis in gastric cancer. However, the biological functions of VPS35 in gastric cancer remain unclear. METHODS: Cell viability assays were performed to examine whether VPS35 affected cell proliferation. Immunoprecipitation and biotin assays showed that VPS35 bound to epidermal growth factor receptor (EGFR) in the cytoplasm and recycled it to the cell surface. Patient-derived xenografts and organoids were used to evaluate the effect of VPS35 on the response of gastric cancer to EGFR inhibitors. FINDINGS: VPS35 expression levels were upregulated in tumour tissues and correlated with local tumour invasion and poor survival in patients with gastric cancer. VPS35 promoted cell proliferation and increased tumour growth. Mechanistically, VPS35 selectively bound to endocytosed EGFR in early endosomes and recycled it back to the cell surface, leading to the downstream activation of the ERK1/2 pathway. We also found that high VPS35 expression levels increased the sensitivity of the xenograft and organoid models to EGFR inhibitors. INTERPRETATION: VPS35 promotes cell proliferation by recycling EGFR to the cell surface, amplifying the network of receptor trafficking. VPS35 expression levels are positively correlated with gastric cancer sensitivity to EGFR inhibitors, which offers a potential method to stratify patients for EGFR inhibitor utilisation. FUNDING: National Natural Science Foundation of China.

Exosomal hsa-let-7g-3p and hsa-miR-10395-3p derived from peritoneal lavage predict peritoneal metastasis and the efficacy of neoadjuvant intraperitoneal and systemic chemotherapy in patients with gastric cancer.

BACKGROUND: The prognosis of advanced gastric cancer (GC) invading the gastric serosa remains poor, mainly owing to high incidence of peritoneal recurrence. Patients with peritoneal metastases are often treated with neoadjuvant intraperitoneal and systemic chemotherapies (NIPS). Good responders to NIPS often undergo conversion gastrectomy. This study aims to explore biomarkers predicting the occurrence of peritoneal metastasis (PM) and evaluating the efficacy of NIPS in GC patients. METHODS: We collected six peritoneal lavage (PL) samples from two patients with PM, two without PM, and two with diminished PM after NIPS via intraperitoneal access ports. We equally isolated microRNAs from exosomes derived from PL samples for deep sequencing. Two microRNAs (hsa-let-7g-3p and hsa-miR-10395-3p) were identified, and their expression levels were examined in PL samples of 99 GC patients using qRT-PCR. Moreover, we performed in vivo and in vitro functional assays to investigate effects of these microRNAs on metastasis and chemoresistance of GC cells. RESULTS: Exosomal microRNA expression profiling of six PL samples indicated that the microRNA signature in exosomes of PLs from patients with diminished PM was similar to that from patients without PM. Expression levels of hsa-let-7g-3p and hsa-miR-10395-3p were associated with PM. In vivo and in vitro functional assays confirmed that hsa-let-7g-3p and hsa-miR-10395-3p are involved in GC metastasis and chemoresistance. CONCLUSION: PL-derived exosomes in GC contain large amounts of microRNAs related to PM. Moreover, hsa-let-7g-3p and hsa-miR-10395-3p could be used as biomarkers predicting PM and NIPS efficacy and are involved in GC metastasis and chemoresistance.

Clinical characteristics and outcomes of gastrointestinal stromal tumor patients receiving surgery with or without TKI therapy: a retrospective real-world study.

PURPOSE: To retrospectively analyze the clinical characteristics of patients undergoing surgical treatment for gastrointestinal stromal tumors (GISTs) in Ruijin Hospital and explore the relevant prognosis clinical factors after surgical treatment. METHODS: We screened out 1015 patients with GISTs diagnosed and treated during January 2010 to December 2019. We performed univariate analysis by the log-rank test and multivariate analysis by COX regression. The Kaplan-Meier method was used to estimate the disease-free survival (DFS) and overall survival (OS) of the whole group. RESULTS: All 1015 patients in the whole group received radical surgery, and the proportion of patients with high, intermediate, and low risk was 31.1%, 21.7%, and 47.3%, respectively. Among the 480 low-risk patients, surgery could achieve radical therapy; only the Ki-67 index was related to DFS and OS (DFS: p = 0.032, OS: p = 0.009) among the 140 intermediate-risk patients with tumors located in the stomach, whether received Tyrosine kinase inhibitors (TKIs) therapy did not affect the prognosis of patients (DFS: p = 0.716, OS: p = 0.848). Among the 331 high-risk patients, those with non-gastric tumors (those outside the stomach, duodenum, and small intestine, HR 1.55, 95% CI 1.19-2.00, p < 0.001), tumor diameter > 10 cm (hazard ratio, HR 2.63, 95% confidence interval, CI 2.09-4.03, p < 0.001), as well as high-risk patients with mitotic rate > 10/50 HPF (HR 2.74, 95% CI 2.00-3.76, p < 0.001), the overall prognosis was obviously worse than that of other patients. For some high-risk patients, prolonged postoperative imatinib therapy could significantly improve the survival of patients (HR 0.43, 95% CI 0.15-0.66, p < 0.001). CONCLUSIONS: For the vast majority of GIST patients, surgery can be curative; but in intermediate-risk patients, the Ki-67 index and postoperative TKI treatment are closely related to prognosis. For intermediate-risk patients whose primary tumor is the stomach, the value of TKI-targeted therapy after surgery seem be not necessary in our study. However, for some high-risk patients, the prognosis of patients can be improved by appropriately prolonging the treatment time of TKI.

Utility of [68Ga]FAPI-04 and [18F]FDG dual-tracer PET/CT in the initial evaluation of gastric cancer.

OBJECTIVES: We aimed to investigate the role of [68Ga]FAPI-04 and [18F]FDG dual-tracer PET/CT for the initial assessment of gastric cancer and to explore the factors associated with their uptake. METHODS: This study enrolled 62 patients with histopathologically confirmed gastric cancer. We compared the diagnostic performance of [68Ga]FAPI-04, [18F]FDG, and combined dual-tracer PET/CT. The standardized uptake value (SUV) and tumor-to-background ratio (TBR) were also measured, and the factors that influence tracer uptake were analyzed. RESULTS: [68Ga]FAPI-04 PET/CT detected more primary lesions (90.3% vs 77.4%, p = 0.008) and peritoneal metastases (91.7% vs 41.7%, p = 0.031) and demonstrated higher SUVmax and TBR values (p < 0.001) of primary lesions compared to [18F]FDG PET/CT. Dual-tracer PET/CT significantly improved the diagnostic sensitivity for the detection of distant metastases, compared with stand-alone [18F]FDG (97.1% vs 73.5%, p = 0.008) or [68Ga]FAPI-04 (97.1% vs 76.5%, p = 0.016) PET/CT. Subsequently, treatment strategies were changed in nine patients following [68Ga]FAPI-04 and [18F]FDG dual-tracer PET/CT. Nevertheless, [68Ga]FAPI-04 uptake was primarily influenced by the size and invasion depth of the tumor. Both [68Ga]FAPI-04 and [18F]FDG PET/CT showed limited sensitivity for detecting early gastric cancer (EGC) (37.5% vs 25.0%, p > 0.05). CONCLUSIONS: In this initial study, [68Ga]FAPI-04 and [18F]FDG dual-tracer PET/CT were complementary and improved sensitivity for the detection of distant metastases pre-treatment in gastric cancer and could improve treatment stratification in the future. [68Ga]FAPI-04 had limited efficacy in detecting EGC. KEY POINTS: • [68Ga]FAPI-04 and [18F]FDG dual-tracer PET/CT are complementary to each other for improving diagnostic sensitivity in the initial evaluation of distant metastases from gastric cancer. • [68Ga]FAPI-04 PET/CT showed limited sensitivity in detecting EGC. • Need for further validation in a larger multi-centre prospective study.

Calponin 1 increases cancer-associated fibroblasts-mediated matrix stiffness to promote chemoresistance in gastric cancer.

The mechanical microenvironment regulated by cancer-associated fibroblasts (CAFs) influence tumor progression. Chemotherapeutic interventions including 5-Fluorouracil (5-Fu) are commonly used for primary treatment of patients with advanced gastric cancer (GC), and the development of acquired resistance to 5-Fu limits the clinical efficacy of these chemotherapies. However, if and how the interplay between CAFs and the mechanical microenvironment regulates GC response to 5-Fu is poorly understood. In this study, we demonstrate that high-level expression of calponin 1(CNN1) in gastric CAFs predicts poor clinical outcomes of GC patients, especially for those treated with 5-Fu. CNN1 knockdown in CAFs improves the effectiveness of 5-Fu in reducing tumor growth in a mouse GC model and confers increased sensitivity to 5-Fu in a 3D culture system. Furthermore, CNN1 knockdown impairs CAF contraction and reduces matrix stiffness without affecting the expression of matrix proteins. Mechanistically, CNN1 interacts with PDZ and LIM Domain 7 (PDLIM7) and prevents its degradation by the E3 ubiquitin ligase NEDD4-1, which leads to activation of the ROCK1/MLC pathway. The increased matrix stiffness, in turn, contributes to 5-Fu resistance in GC cells by activating YAP. Taken together, our data reveal a critical role of the mechanical microenvironment in 5-Fu resistance, which is modulated by CNN1hi CAFs-mediated matrix stiffening, indicating that targeting CAFs may provide a novel option for overcoming drug resistance in GC.

DKK1 as a robust predictor for adjuvant platinum chemotherapy benefit in resectable pStage II-III gastric cancer.

BACKGROUND: Adjuvant chemotherapy (ACT) with 5-FU alone or 5-FU plus platinum after curative surgery improves the prognosis of pStage II-III gastric cancer (GC). However, only a subset of patients benefits from adjuvant platinum. To avoid the side effects of platinum, it is significant to accurately screen the patients who would benefit maximally with this treatment. The present study aimed to assess the value of DKK1 in predicting the benefit of adjuvant platinum chemotherapy in patients with pStage II -III GC. METHODS: Platinum sensitivity-related genes were screened by bioinformatics. DKK1 expression in 380 GC specimens was detected by immunohistochemistry (IHC) staining, and the correlation with adjuvant platinum-specific benefits were analyzed. RESULTS: DKK1 was screened as the most significant platinum sensitivity-related gene. In patients with DKK1high GC, the estimated absolute 5-year overall survival (OS) benefits from adjuvant platinum for pStage II-III, II, IIIA, IIIB, and IIIC were 25.5%, 17.3%, 36.4%, 29.2% and 31.1%, respectively, and the estimated absolute 5-year disease-free survival (DFS) benefits in the corresponding stages were 27.4%, 17.5%, 36.7%, 29.7% and 31.5%, respectively. These benefits were significantly higher than those in the same TNM stage without adjusting for DKK1 status. The performance of DKK1 was independent of the TNM stage and other clinicopathological variables. Similar results were obtained in the TCGA and ACRG cohorts. Furthermore, nomograms were constructed to predict the survival benefits in DKK1 subgroups. CONCLUSIONS: The stratification strategy based on DKK1 status is more precise than the TNM staging system for the selection of pStage II-III GC patients suitable for platinum-containing ACT.

Benchmark for establishment of organoids from gastrointestinal epithelium and cancer based on available consumables and reagents.

Gastrointestinal cancers are a public health problem that threatens the lives of human being. A good experimental model is a powerful tool to promote the uncovering pathogenesis and establish novel treatment methods. High-quality biomedical research requires experimental models to recapitulate the physiological and pathological states of their parental tissues as much as possible. Organoids are such experimental models. Organoids refer to small organ-like cellular clusters formed by the expansion and passaging of living tissues in 3D culture medium in vitro. Organoids are highly similar to the original tissues in terms of cellular composition, cell functions, and genomic profiling. Organoids have many advantages, such as short preparation cycles, long-term storage based on cryopreservation, and reusability. In recent years, researchers carried out the establishment of organoids from gastrointestinal mucosa and cancer tissues, and accumulated valuable experiences. In order to promote effective usage and further development of organoid-related technologies in the research of gastrointestinal diseases, this study proposes a benchmark based on utilization of available experimental consumables and reagents, which are involved in the key steps such as collection and pretreatment of biospecimen, organoid construction, organoid cryopreservation and recovery, growth status evaluation, and organoid quality control. We believe that the standard for the construction and preservation of organoids derived from human gastrointestinal epithelium and cancer tissues can provide an important reference for the majority of scientific researchers.

Prognostic risk assessment model and drug sensitivity analysis of colon adenocarcinoma (COAD) based on immune-related lncRNA pairs.

PURPOSE: The aim of this study was to identify and screen long non-coding RNA (lncRNA) associated with immune genes in colon cancer, construct immune-related lncRNA pairs, establish a prognostic risk assessment model for colon adenocarcinoma (COAD), and explore prognostic factors and drug sensitivity. METHOD: Our method was based on data from The Cancer Genome Atlas (TCGA). To begin, we obtained all pertinent demographic and clinical information on 385 patients with COAD. All lncRNAs significantly related to immune genes and with differential expression were identified to construct immune lncRNA pairs. Subsequently, least absolute shrinkage and selection operator and Cox models were used to screen out prognostic-related immune lncRNAs for the establishment of a prognostic risk scoring formula. Finally, We analysed the functional differences between subgroups and screened the drugs, and establish an individual prediction nomogram model. RESULTS: Our final analysis confirmed eight lncRNA pairs to construct prognostic risk assessment model. Results showed that the high-risk and low-risk groups had significant differences (training (n = 249): p < 0.001, validation (n = 114): p = 0.022). The prognostic model was certified as an independent prognosis model. Compared with the common clinicopathological indicators, the prognostic model had better predictive efficiency (area under the curve (AUC) = 0.805). Finally, We have analysed highly differentiated cellular pathways such as mucosal immune response, identified 9 differential immune cells, 10 sensitive drugs, and establish an individual prediction nomogram model (C-index = 0.820). CONCLUSION: Our study verified that the eight lncRNA pairs mentioned can be used as biomarkers to predict the prognosis of COAD patients. Identified cells, drugs may have an positive effect on colon cancer prognosis.

CHRDL2 promotes cell proliferation by activating the YAP/TAZ signaling pathway in gastric cancer.

The encoding product of Chordin-like 2 (CHRDL2) is a member of the chordin family of proteins, which has been shown to be aberrantly expressed in several types of solid tumors. The regulatory underlying mechanisms of CHRDL2, however, remain poorly understood in gastric cancer (GC). In the present study, we determined that CHRDL2 was abnormally upregulated in human gastric cancer tissues compared with adjacent normal tissues. We also showed that CHRDL2 was positively associated with T stage, the pathological stage, distant metastasis, and poor patient prognosis. Furthermore, the serum level of CHRDL2 was obviously higher in GC patients than normal people, and is positively correlated with later TNM stage, deeper T stage, later N stage and poorer differentiation. Moreover, we verified that overexpressing CHRDL2 promoted the proliferation and cell cycle transition of GC cells both in vitro and in vivo, whereas the opposite results were observed in CHRDL2-depleted cells. In addition, the phosphorylation levels of Yes-associated protein (YAP), transcriptional coactivator with PDZ-binding motif (TAZ) and the total levels MST2 were decreased in CHRDL2 overexpressing cells. Consistent with previous findings, we observed the converse results in CHRDL2-silenced GC cells. Additionally, knockdown of YAP and overexpression of STK3 (MST2) could reverse the effects of CHRDL2 overexpression-induced proliferation of GC cells in vitro. Taken together, CHRDL2 plays a key role by activating the YAP/TAZ pathway in gastric cancer. Therefore, CHRDL2 could serve as a potential therapeutic tool for the treatment of gastric cancer.