Gastric cancer surgery: the importance of technique and not only the extent of lymph node dissection

CircPTK2 Suppresses the Progression of Gastric Cancer by Targeting the MiR-196a-3p/AATK Axis

Background

Gastric cancer is a type of malignant tumor with high morbidity and mortality. It has been shown that circular RNAs (circRNAs) exert critical roles in gastric cancer progression via working as microRNA (miRNA) sponges to regulate gene expression. However, the role and potential molecular mechanism of circRNAs in gastric cancer remain largely unknown.

Methods

CircPTK2 (hsa_circ_0005273) was identified by bioinformatics analysis and validated by RT-qPCR assay. Bioinformatics prediction, dual-luciferase reporter, and RNA pull-down assays were used to determine the interaction between circPTK2, miR-196a-3p, and apoptosis-associated tyrosine kinase 1 (AATK).

Results

The level of circPTK2 was markedly downregulated in gastric cancer tissues and gastric cancer cells. Upregulation of circPTK2 significantly suppressed the proliferation, migration, and invasion of gastric cancer cells, while circPTK2 knockdown exhibited opposite effects. Mechanically, circPTK2 could competitively bind to miR-196a-3p and prevent miR-196a-3p to reduce the expression of AATK. In addition, overexpression of circPTK2 inhibited tumorigenesis in a xenograft mouse model of gastric cancer.

Conclusion

Collectively, circPTK2 functions as a tumor suppressor to suppress gastric cancer cell proliferation, migration, and invasion through regulating the miR-196a-3p/AATK axis, suggesting that circPTK2 may serve as a novel therapeutic target for gastric cancer.

Clinical implications of Indocyanine Green Fluorescence Imaging-Guided laparoscopic lymphadenectomy for patients with gastric cancer: A cohort study from two randomized, controlled trials using individual patient data

BACKGROUND

The value of indocyanine green (ICG) fluorescence imaging in tracing metastatic lymph nodes (LNs) has rarely been reported. We aimed to evaluate the clinical implications of fluorescence imaging-guided lymphadenectomy and the sensitivity of fluorescent lymphography to detect metastatic LN stations in gastric cancer (GC).

MATERIALS AND METHODS

This analysis pooled data from two randomized controlled trials (FUGES-012 and FUGES-019 studies) on laparoscopic ICG tracer-guided lymphadenectomy for GC between November 2018 and October 2020. Patients who received ICG injection using either the intraoperative subserosal or preoperative submucosal approaches 1 day before surgery and underwent fluorescence imaging-guided lymphadenectomy were defined as the ICG group. Patients who underwent conventional lymphadenectomy without ICG injection and intraoperative imaging were defined as the non-ICG group.

RESULTS

Among 514 enrolled patients, the ICG and non-ICG groups included 385 and 129, respectively. A significantly higher mean number of LNs was retrieved in the ICG group than in the non-ICG group (49.9 vs. 42.0, P < 0.001). The ICG group showed a lower LN noncompliance rate than that in the non-ICG group (31.9% vs. 57.4%, P < 0.001). The sensitivity of fluorescence imaging for detecting all metastatic LN stations was 86.8%. The negative predictive value was 92.2% for nonfluorescent stations. For detecting all metastatic stations, subgroup analysis revealed 97.7%, 91.7%, 86.2%, and 84.3% sensitivities for pT1, pT2, pT3, and pT4a tumors, respectively. Regardless of gastrectomy type, the diagnostic accuracy for detecting all metastatic stations in the D1+ and D2 stations for cT1-cT2 disease reached 100%.

CONCLUSION

ICG fluorescence imaging, using either the subserosal or submucosal approaches, assisted in the thorough dissection of potentially metastatic LNs, as recommended for individualized laparoscopic lymphadenectomy for GC.

TRIM22 inhibits the proliferation of gastric cancer cells through the Smad2 protein

TRIM22 is involved in tumorigenesis and development, but its mechanism is not clear. In this study, we investigated the expression and biological role of TRIM22 in gastric cancer. We found that TRIM22 mRNA and protein expression was abnormally low in gastric cancer tissues and cells and correlated with tumor size and depth of invasion. Overexpression of TRIM22 significantly inhibited the proliferation, colony formation, and migration of gastric cancer cells and downregulated the expression of HSPA6. However, the HSPA6-siRNA complementation test showed that TRIM22 did not regulate cell proliferation through HSPA6. Furthermore, overexpression of TRIM22 downregulated the phosphorylation of Smad2 and Smad3. In addition, TRIM22 directly binds to Smad2, and overexpression of Smad2 can reverse the inhibition of cell proliferation and migration induced by TRIM22. In vivo, overexpression of TRIM22 significantly inhibited the growth of subcutaneous xenografts in nude mice. Our study indicates that TRIM22 has an important role in the development of gastric cancer and may inhibit the proliferation of gastric cancer cells through Smad2.

HOXB13 promotes gastric cancer cell migration and invasion via IGF-1R upregulation and subsequent activation of PI3K/AKT/mTOR signaling pathway

AIMS

This study aimed at exploring HOXB13 expression and function in gastric cancer (GC), and the underlying molecular mechanism.

MATERIALS AND METHODS

HOXB13 and fat mass and obesity-associated protein (FTO) expression in GC and non-GC tissues of GC patients were analyzed using Gene Expression Profiling Interactive Analysis (GEPIA) and verified by quantitative reverse transcription-polymerase chain reaction (RT-qPCR) and western blotting. The regulatory relationship between FTO and HOXB13 was verified via RT-qPCR, methylated RNA immunoprecipitation sequencing (MeRIP-seq), and double luciferase reporter gene assay. The effects of HOXB13 and FTO on proliferation, invasion, and migration of GC cells were studied using EdU and Transwell assays.

KEY FINDINGS

HOXB13 and FTO expression was abnormally high in GC tissues and cell lines, with no significant correlation between HOXB13 and FTO expression and the prognosis of GC patients. Inhibiting FTO expression in GC cells decreased HOXB13 methylation and upregulated HOXB13 expression. Inhibiting HOXB13 and FTO expression suppressed GC cell proliferation, migration, and invasion. Decreased HOXB13 expression suppressed PI3K/AKT/mTOR signaling pathway activity, while atypical HOXB13 expression promoted it. A probable downstream target of HOXB13 was insulin-like growth factor 1 receptor (IGF-1R); a decrease in IGF-1R relieved GC cell migration, invasion, and proliferation and inhibited PI3K/AKT/mTOR signaling pathway activity promoted by atypical HOXB13 expression.

SIGNIFICANCE

HOXB13 and FTO expression is elevated in GC. FTO suppresses HOXB13 methylation; FTO and HOXB13 expression promotes GC cell proliferation, migration, and invasion. HOXB13 expression intensifies GC invasion through PI3K/AKT/mTOR signaling via IGF-1R. HOXB13 and associated signaling pathways can be effective targets for GC therapy.

Safety and Feasibility of No.12a Lymph Node Dissection by Portal Vein Approach in Radical Laparoscopic Gastrectomy for Gastric Cancer

Background:

Traditional laparoscopic No.12a lymph node dissection in radical gastrectomy for gastric cancer may damage the peripheral blood vessels, and is not conducive to the full exposure of the portal vein and the root ligation of the left gastric vein. We recommend a new surgical procedure, the portal vein approach, to avoid these problems.

Methods:

25 patients with advanced gastric cancer underwent radical laparoscopic gastrectomy and No.12a lymph node were dissected by portal vein approach, including 7 cases with total gastrectomy, 18 cases with distal gastric resection, 14 males and 11 females. Operative time, intraoperative blood loss, time to first flatus, postoperative hospital stay, number of total lymph node dissection and No.12a lymph node dissection, No.12a lymph node metastasis rate and postoperative complications were statistically observed.

Results:

All the patients were operated successfully and No.12a lymph node were cleaned by portal vein approach. A total of 683 lymph nodes were dissected, with the average number of lymph nodes dissection and positive lymph nodes were (27.3 ± 12.7) and (3.8 ± 5.6) respectively. The average number of No.12a lymph node dissection was (2.4 ± 1.95) and the metastasis rate of No.12a lymph node was 16% (4/25). The average operation time of radical laparoscopic distal and total gastrectomy were (239.2 ± 51.4) min and (295.1 ± 27.7) min respectively. The mean intraoperative blood loss was (134.0 ± 65.7) ml, and postoperative first anal exhaust time was (2.24 ± 0.86) d. The mean time to fluid intake was (4.2 ± 1.7) d, and postoperative hospitalization time was (9.6 ± 5.0) d. Without portal vein injure, anastomotic leakage, gastrointestinal bleeding, intestinal obstruction and other complications were observed in all patient.

Conclusion:

Our results show that the laparoscopic No.12a lymph node dissection by portal vein approach for gastric cancer is safe, feasible and has certain clinical application value.

Multivisceral resection for locally advanced gastric cancer: A retrospective study

BACKGROUND

Multivisceral resection may be the exclusive radical procedure for cT4b gastric cancer patients. However, most surgeons refuse to select surgery because of the theoretical higher mortality, morbidity and poorer prognosis.

METHODS

We retrospectively reviewed cT4b gastric cancer patients who underwent surgery from January 1,1997 to December 31,2018. The primary endpoint was overall survival. Short-term results and prognostic values of clinical and pathologic factors were also analyzed.

RESULTS

Patients underwent multivisceral resection had an acceptable mortality and morbidity. The overall 5-year survival rate of multivisceral resection was higher than that of palliative surgery (P < 0.05). And independent prognostic factors of multivisceral resection were R+ resection, extensive lymph node involved (>15), vascular cancer emboli, and postoperative chemotherapy.

CONCLUSIONS

cT4b gastric cancer patients underwent multivisceral resection experience acceptable mortality and morbidity. The independent prognostic factors for multivisceral resection were completeness of resection, extensive lymph node involvement (>15), vascular cancer emboli, and postoperative chemotherapy.