Single-cell RNA sequencing reveals immune cell dysfunction in the peripheral blood of patients with highly aggressive gastric cancer.

Highly aggressive gastric cancer (HAGC) is a gastric cancer characterized by bone marrow metastasis and disseminated intravascular coagulation (DIC). Information about the disease is limited. Here we employed single-cell RNA sequencing to investigate peripheral blood mononuclear cells (PBMCs), aiming to unravel the immune response of patients toward HAGC. PBMCs from seven HAGC patients, six normal advanced gastric cancer (NAGC) patients, and five healthy individuals were analysed by single-cell RNA sequencing. The expression of genes of interest was validated by bulk RNA-sequencing and ELISA. We found a massive expansion of neutrophils in PBMCs of HAGC. These neutrophils are activated, but immature. Besides, mononuclear phagocytes exhibited an M2-like signature and T cells were suppressed and reduced in number. Analysis of cell-cell crosstalk revealed that several signalling pathways involved in neutrophil to T-cell suppression including APP-CD74, MIF-(CD74+CXCR2), and MIF-(CD74+CD44) pathways were increased in HAGC. NETosis-associated genes S100A8 and S100A9 as well as VEGF, PDGF, FGF, and NOTCH signalling that contribute to DIC development were upregulated in HAGC too. This study reveals significant changes in the distribution and interactions of the PBMC subsets and provides valuable insight into the immune response in patients with HAGC. S100A8 and S100A9 are highly expressed in HAGC neutrophils, suggesting their potential to be used as novel diagnostic and therapeutic targets for HAGC.

Induction of filopodia formation by α-Actinin-2 via RelA with a feedforward activation loop promoting overt bone marrow metastasis of gastric cancer.

BACKGROUND: Bone marrow metastasis (BMM) is underestimated in gastric cancer (GC). GC with BMM frequently complicate critical hematological abnormalities like diffused intravascular coagulation and microangiopathic hemolytic anemia, which constitute a highly aggressive GC (HAGC) subtype. HAGC present a very poor prognosis with peculiar clinical and pathological features when compared with not otherwise specified advanced GC (NAGC). But the molecular mechanisms underlying BMM from GC remain rudimentary. METHODS: The transcriptomic difference between HAGC and NAGC were analyzed. Genes that were specifically upregulated in HAGC were identified, and their effect on cell migration and invasion was studied. The function of ACTN2 gene were confirmed by GC cell lines, bone-metastatic animal model and patients' tissues. Furthermore, the molecular mechanism of ACTN2 derived-BMM was explored by multiple immunofluorescence staining, western blot, chromatin immunoprecipitation, and luciferase reporter assays. RESULTS: We elucidated the key mechanisms of BMM depending on the transcriptomic difference between HAGC and NAGC. Five genes specifically upregulated in HAGC were assessed their effect on cell migration and invasion. The ACTN2 gene encoding protein α-Actinin-2 was detected enhanced the metastatic capability and induced BMM of GC cells in mouse models. Mechanically, α-Actinin-2 was involved in filopodia formation where it promoted the Actin filament cross-linking by replacing α-Actinin-1 to form α-Actinin-2:α-Actinin-4 complexes in GC cells. Moreover, NF-κB subunit RelA and α-Actinin-2 formed heterotrimers in the nuclei of GC cells. As a direct target of RelA:α-Actinin-2 heterotrimers, the ACTN2 gene was a positive auto-regulatory loop for α-Actinin-2 expression. CONCLUSIONS: We demonstrated a link between filopodia, BMM and ACTN2 activation, where a feedforward activation loop between ACTN2 and RelA is established via actin in response to distant metastasis. Given the novel filopodia formation function and the new mechanism of BMM in GC, we propose ACTN2 as a druggable molecular vulnerability that may provide potential therapeutic benefit against BMM of GC.

Neoadjuvant Immunotherapy Leads to Major Response and Low Recurrence in Localized Mismatch Repair-Deficient Colorectal Cancer.

BACKGROUND: Our study aimed to evaluate the efficacy and feasibility of neoadjuvant anti-PD-1 treatment for localized mismatch repair-deficient (dMMR) colorectal cancer (CRC). PATIENTS AND METHODS: The study cohort included patients with localized dMMR CRC who received PD-1 inhibitors as neoadjuvant therapy from 3 medical centers in Southern China. Main eligibility criteria included age between 18 and 75 years, ECOG performance status of 0 or 1, and receipt of ≥2 doses of PD-1 inhibitors. RESULTS: A total of 73 patients were included. Most of the tumors were locally advanced, including 19 (26.0%) T4a and 29 (39.7%) T4b. Most patients (79.5%) received PD-1 inhibitor monotherapy. Objective response per radiologic assessment was achieved in 62 (84.9%) patients, including 17 (23.3%) with complete response (CR) and 45 (61.6%) with partial response, with a median time to response of 9.6 weeks. Patients with T4a/4b disease had a similar response rate as those with T2-3 disease (84.0% vs 85.4%; P=.999). As of writing, a total of 50 patients have undergone surgery. Pathologic CR was achieved in most (57.1%) patients and remained high (59.5%) even among the 38 patients with T4a/4b disease. The 17 patients with CR did not undergo surgery and adopted a watch-and-wait strategy. After a median follow-up of 17.2 months (range, 3.4-45.1 months), the overall median recurrence-free and overall survivals were not reached. Among patients undergoing surgery or achieving CR, the 2-year tumor-specific disease-free and overall survival rates were both 100%. During neoadjuvant treatment, grade 3-4 adverse events occurred in 8 patients; 4 required acute intervention. Severe postoperative complications were recorded in 4 patients, 3 of whom required a second surgery. CONCLUSIONS: Neoadjuvant therapy with PD-1 blockade is highly effective for localized dMMR CRC, with an acceptable safety profile and low recurrence rate. This treatment holds promise for becoming the new standard of care for localized dMMR CRCs.

Whole-exome sequencing analysis identifies distinct mutational profile and novel prognostic biomarkers in primary gastrointestinal diffuse large B-cell lymphoma.

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive non-Hodgkin lymphoma, and about 10% of DLBCL cases primarily occur in the gastrointestinal tract. Previous reports have revealed that primary gastrointestinal-DLBCL (pGI-DLBCL) harbors different genetic mutations from other nodal or extranodal DLBCL. However, the exonic mutation profile of pGI-DLBCL has not been fully addressed. METHODS: We performed whole-exome sequencing of matched tumor tissues and blood samples from 53 pGI-DLBCL patients. The exonic mutation profiles were screened, and the correlations between genetic mutations and clinicopathological characteristics were analyzed. RESULTS: A total of 6,588 protein-altering events were found and the five most frequent mutated genes in our pGI-DLBCL cohort were IGLL5 (47%), TP53 (42%), BTG2 (28%), P2RY8 (26%) and PCLO (23%). Compared to the common DLBCL, significantly less or absence of MYD88 (0%), EZH2 (0%), BCL2 (2%) or CD79B (8%) mutations were identified in pGI-DLBCL. The recurrent potential driver genes were mainly enriched in pathways related to signal transduction, infectious disease and immune regulation. In addition, HBV infection had an impact on the mutational signature in pGI-DLBCL, as positive HBsAg was significantly associated with the TP53 and LRP1B mutations, two established tumor suppressor genes in many human cancers. Moreover, IGLL5 and LRP1B mutations were significantly correlated with patient overall survival and could serve as two novel prognostic biomarkers in pGI-DLBCL. CONCLUSIONS: Our study provides a comprehensive view of the exonic mutation profile of the largest pGI-DLBCL cohort to date. The results could facilitate the clinical development of novel therapeutic and prognostic biomarkers for pGI-DLBCL.

Integrated driver mutations profile of chinese gastrointestinal-natural killer/T-cell lymphoma.

Background: One of the most common nasal external sites in extranodal Natural Killer/T-cell lymphoma (NKTCL) is in the gastrointestinal (GI) system. Despite this, reports on gastrointestinal-Natural Killer/T-cell lymphoma (GI-NKTCL) are very few. To obtain a better understanding of this manifestation of NKTCL, we conducted a retrospective study on GI-NKTCL to analyze its clinical features, genomic changes and immune infiltration. Methods: We retrospectively collected patients diagnosed with GI-NKTCL in the Sixth Affiliated Hospital of Sun Yat-sen University from 2010 to 2020. From this cohort we obtained mutation data via whole exome sequencing. Results: Genomic analysis from 15 patients with GI-NKTCL showed that the most common driving mutations were ARID1B(14%, 2/15), ERBB3(14%, 2/15), POT1(14%, 2/15), and TP53(14%, 2/15). In addition, we found the most common gene mutation in patients with GI-NKTCL to be RETSAT(29%, 4/15) and SNRNP70(21%, 3/15), and the most common hallmark pathway mutations to be G2M checkpoint pathway (10/15, 66.7%), E2F targets (8/15, 53.3%), estrogen response late (7/15, 46.7%), estrogen response early (7/15, 46.7%), apoptosis (7/15, 46.7%) and TNFA signaling via NFKB (7/15, 46.7%). In the ICIs-Miao cohort, SNRNP7-wild-type (WT) melanoma patients had significantly prolonged overall survival (OS) time compared with SNRNP7 mutant type (MT) melanoma patients. In the TCGA-UCEC cohort, the patients with RETSAT-MT or SNRNP7-MT had significantly increased expression of immune checkpoint molecules and upregulation of inflammatory immune cells. Conclusions: In this study, we explored GI-NKTCL by means of genomic analysis, and identified the most common mutant genes (RETSAT and SNRNP70), pathway mutations (G2M checkpoint and E2F targets) in GI-NKTCL patients. Also, we explored the association between the common mutant genes and immune infiltration. Our aim is that our exploration of these genomic changes will aid in the discovery of new biomarkers and therapeutic targets for those with GI-NKTCL, and finally provide a theoretical basis for improving the treatment and prognosis of patients with GI-NKTCL.

Acupuncture for Quality of Life in Gastric Cancer Patients Undergoing Adjuvant Chemotherapy.

CONTEXT: Patients with gastric cancer experience health-related quality of life (HRQOL) decline during adjuvant chemotherapy following gastrectomy. OBJECTIVES: This pilot study aimed to evaluate the preliminary effect and feasibility of electro-acupuncture (EA) for HRQOL and symptom burden in these patients. METHODS: In this open-label, multicenter, parallel controlled trial, gastric cancer patients who planned to receive adjuvant chemotherapy were randomly assigned to receive high-dose EA (seven times each chemotherapy cycle for three cycles), low-dose EA (three times each chemotherapy cycle), or usual care only. The acupoints prescription consisted of bilateral ST36, PC6, SP4, and DU20, EX-HN3, and selected Back-shu points. Patients completed the Functional Assessment of Cancer Therapy-Gastric (FACT-Ga) weekly, and the Edmonton Symptom Assessment System (ESAS). The primary outcome was the difference among the groups on the gastric cancer subscale (GaCS) of the FACT-Ga. RESULTS: Of the 66 randomized patients, 58 were analyzed according to intention-to-treat principle, and 45 were in the per-protocol set (PPS). The average scores in PPS of GaCS were 52.12±9.71, 51.85±12.36, and 45.37±8.61 in high-dose EA, low-dose EA, and control groups, respectively. EA was significantly associated with improved average GaCS scores when compared with control group (51.98±10.91 vs. 45.37±8.61, P = 0.039). EA treatment also produced ESAS relief at the end of intervention (14.36 ± 12.28 vs. 23.91 ± 15.52, P = 0.027). Participants in EA groups had fewer grade ≥3 leukopenia (0% vs. 15.79%, P = 0.031) and neutropenia (2.56% vs. 26.31%, P = 0.012). CONCLUSION: EA showed promising effects in improving HRQOL, controlling symptom burden, and reducing toxicity during adjuvant chemotherapy in gastric cancer patients. Future adequately powered trials are feasible and needed to confirm the specific effect of EA.

[Safety and efficacy analysis on modified FOLFOXIRI as first-line treatment for advanced colorectal cancer in China-single center experience].

OBJECTIVE: To evaluate the safety and preliminary efficacy of modified FOLFOXIRI (combination of reducing dosage irinotecan, oxaliplatin and fluorouracil) in first-line treatment for patients with metastatic colorectal cancer. METHOD: A total of 53 patients with advanced colorectal cancer receiving modified FOLFOXIRI regimen were recruited continuously from January 2010 to January 2014. Safety profile was recorded based on NCI Common Terminology Criteria for Adverse Events version 3.0 (NCI-CTCAE v3.0). Objective response was evaluated by Response Evaluation Criteria in Solid Tumors version1.1 (RECIST 1.1) after administration of at least 4 cycles chemotherapy. Kras and Braf gene sequencing was tested by dideoxy chain-termination method. Relation between efficacy and two genes was examined. RESULTS: Among 53 patients, no treatment-related mortality was presented. The rate of grade 3 to 4 adverse event was 32.1% (17/53), including neutropenia 13.2%(7/53), anemia 11.3% (6/53) and fatigue 9.4% (5/53). Overall response rate (ORR) and disease control rate (DCR) were respectively 65.9% (29/44) and 90.0% (40/44). Radical resection rate (R0) was 29.5% (13/44). Efficacy of mFOLFOXIRI regimen plus targeting therapy was assessed in 44 patients. mFOLFOXIRI regimen plus targeting therapy achieved an ORR of 72.7% (8/11), which was higher than the ORR 65.9% (21/33) of triplet regimen alone, but the difference was not statistically significant (P=0.198). Paraffin specimens of 48 colorectal cancer cases were tested. Twenty-one cases were Kras mutant (43.75%), 3 cases were Braf mutant (6.25%). There were no significant differences between two groups (P>0.05). CONCLUSION: Reducing dosage mFOLFOXIRI can be safely used in advanced colorectal cancer and can achieve promising results in terms of short term efficacy.