LncRNA UCA1 promotes vasculogenic mimicry by targeting miR-1-3p in gastric cancer.

Long non-coding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) has been implicated in several tumors. UCA1 promotes cell proliferation, migration and invasion of GC cells, but the molecular mechanism has not been fully elucidated. This study revealed the oncogenic effects of UCA1 on cell growth and invasion. Furthermore, UCA1 expression was significantly correlated with the overall survival of GC patients, and the clinicopathological indicators, including tumor size, depth of invasion, lymph node metastasis, and TNM stage. Additionally, miR-1-3p was identified as a downstream target of UCA1, which was negatively regulated by UCA1. MiR-1-3p inhibited cell proliferation and vasculogenic mimicry (VM), and induced cell apoptosis by upregulating BAX, BAD, and tumor suppressor TP53 expression levels. Moreover, miR-1-3p almost completely reversed the oncogenic effect caused by UCA1, including cell growth, migration and VM formation. This study also confirmed UCA1 promoted tumor growth in vivo. In this study, we also revealed the correlation between UCA1 and VM formation, which is potentially crucial for tumor metastasis. Meanwhile, its downstream target miR-1-3p inhibited VM formation in GC cells. In summary, these findings indicate that UCA1/miR-1-3p axis is potential target for GC treatment.

A humanized 4-1BB-targeting agonistic antibody exerts potent antitumor activity in colorectal cancer without systemic toxicity.

BACKGROUND: Colorectal cancer (CRC) is one of the most common malignancies and the patient survival rate remains unacceptably low. The anti-programmed cell death-1 (PD-1)/programmed cell death ligand 1 (PD-L1) antibody-based immune checkpoint inhibitors have been added to CRC treatment regimens, however, only a fraction of patients benefits. As an important co-stimulatory molecule, 4-1BB/CD137 is mainly expressed on the surface of immune cells including T and natural killer (NK) cells. Several agonistic molecules targeting 4-1BB have been clinically unsuccessful due to systemic toxicity or weak antitumor effects. We generated a humanized anti-4-1BB IgG4 antibody, HuB6, directed against a unique epitope and hypothesized that it would promote antitumor immunity with high safety. METHODS: The antigen binding specificity, affinity and activity of HuB6 were determined by enzyme-linked immunosorbent assay (ELISA), surface plasmon resonance (SPR), biolayer interferometry (BLI) and flow cytometry. The antitumor effects were evaluated in humanized mice bearing syngeneic tumors, and possible toxicity was evaluated in humanized mice and cynomolgus monkeys. RESULTS: HuB6 showed high specificity and affinity for a binding epitope distinct from those of other known 4-1BB agonists, including utomilumab and urelumab, and induced CD8 + T, CD4 + T and NK cell stimulation dependent on Fcγ receptor (FcγR) crosslinking. HuB6 inhibited CRC tumor growth in a dose-dependent manner, and the antitumor effect was similar with urelumab and utomilumab in humanized mouse models of syngeneic CRC. Furthermore, HuB6 combined with an anti-PD-L1 antibody significantly inhibited CRC growth in vivo. Additionally, HuB6 induced antitumor immune memory in tumor model mice rechallenged with 4 × 106 tumor cells. Toxicology data for humanized 4-1BB mice and cynomolgus monkeys showed that HuB6 could be tolerated up to a 180 mg/kg dose without systemic toxicity. CONCLUSIONS: This study demonstrated that HuB6 should be a suitable candidate for further clinical development and a potential agent for CRC immunotherapy.

A novel 4-1BB/HER2 bispecific antibody shows potent antitumor activities by increasing and activating tumor-infiltrating T cells.

Resistance to HER2-targeted therapy narrows the efficacy of cancer immunotherapy. Although 4-1BB/CD137 is a promising drug target as a costimulatory molecule of immune cells, no therapeutic drug has been approved in the clinic because of systemic toxicity or limited efficacy. Previously, we developed a humanized anti-HER2 monoclonal antibody (mAb) HuA21 and anti-4-1BB mAb HuB6 with distinct antigen epitopes for cancer therapy. Here, we generated an Fc-muted IgG4 HER2/4-1BB bispecific antibody (BsAb) HK006 by the fusion of HuB6 scFv and HuA21 Fab. HK006 exhibited synergistic antitumor activity by blocking HER2 signal transduction and stimulating the 4-1BB signaling pathway simultaneously and strictly dependent on HER2 expression in vitro and in vivo. Strikingly, HK006 treatment enhanced antitumor immunity by increasing and activating tumor-infiltrating T cells. Moreover, HK006 did not induce nonspecific production of proinflammatory cytokines and had no obvious toxicity in mice. Overall, these data demonstrated that HK006 should be a promising candidate for HER2-positive cancer immunotherapy.

Src inhibitor dasatinib sensitized gastric cancer cells to cisplatin.

Gastric cancer (GC) is characterized by high incidence and mortality, and lacks effective treatment. Surgery, combined with chemo- and radiation therapy, represents the cornerstones of GC treatment. Although platinum is commonly used, severe side effects and drug resistance limited its application. Cisplatin-induced cell death mainly relies on the increment of reactive oxygen species (ROS), while the effect of dasatinib on ROS is inconclusive. In this article, dasatinib and cisplatin showed various anti-cancer properties on GC cells, which might be related to the changes of ROS levels. However, NAC enhanced cell death induced by dasatinib, although it elevated ROS levels in GES1 and AGS cells, suggesting that the elevation of ROS levels was not the responsible mechanism. Notably, dasatinib markedly synergized cells against cisplatin. Dasatinib decreased pSer473 Akt levels, and increased p53 expression, which was confirmed by LY294002 or Nutlin-3a co-treatment. Furthermore, transcriptome sequencing also confirmed that the PI3K/AKT pathway was involved in the anti-cancer effect of dasatinib or combined with cisplatin. Additionally, GC cells with higher Src activity (AGS) elicited more sensitive to dasatinib than lower cells (SGC7901 and MGC803), suggesting that the Src levels could be applied to pre-select patients who would benefit from dasatinib and/or combined with platinum compounds.

[Application of intraoperative ultrasound in laparoscopic lymphadenectomy of gastric cancer].

OBJECTIVE: To explore the application value of intraoperative ultrasound (IU) in laparoscopic lymphadenectomy of gastric cancer. METHODS: Patients with gastric cancer undergoing laparoscopic radical D2 gastrectomy at General Surgery of the Second Affiliated Hospital of Anhui Medical University between August 2016 and May 2018 were prospectively enrolled and were randomly divided into IU group (n=78) and conventional group (n=91). The conventional group underwent laparoscopy only. In IU group, the laparoscopy examination was followed with intraoperative ultrasound by ultrasound specialist. The lesser curvature, peripheral gastric organs and gastric lymph nodes were scanned. Lymph nodes were considered positive if maximum diameter was greater than 10 mm or internal hyperechoic features and normal oval shape were lost. The postoperative pathological results were used as the gold standard to analyze the sensitivity of positive lymph nodes by IU detection [true positive lymph nodes/(true positive lymph node+false negative lymph nodes)×100%], specificity [true negative lymph nodes/(true negative lymph nodes+false positive lymph nodes)×100%] and the accuracy rate[(true positive lymph nodes+ true negative lymph nodes/total lymph nodes)×100%]. A consistency check between N staging diagnosed by IU and by postoperative pathology was performed with Kappa test(Kappa>0.75 indicating good consistency). Number of dissected lymph node, number of positive lymph node detected by pathology and the operation time were compared between the IU group and the conventional group. RESULTS: Among 169 gastric cancer patients, 95 were males and 74 were females with age of (63±8) years. Among 1 794 lymph nodes detected by IU from 78 patients in IU group, predicted positive lymph nodes were 832 and 740 positive nodes were confirmed by postoperative pathology. True positive lymph nodes were 679 and true negative lymph nodes were 901 by IU, and a total of 1 580 lymph nodes were accurately diagnosed by IU. The sensitivity and specificity of IU for N staging of gastric cancer were 91.8%(679/740) and 85.5%(901/1 054), respectively. Overall accuracy was 88.1%(1 580/1 794), which was in good accordance with postoperative N staging(Kappa=0.758). There was no significant difference in number of lymph node detected between the IU group and conventional group during laparoscopic gastric cancer surgery(23.0±6.9 vs. 22.0±7.7, t=0.880, P=0.380). However, the numbers of lymph nodes in the third station (No.10, No.11, No.12) in the IU group were significantly higher than those in the conventional group [No.10: median 1 (0-1) vs. 0 (0-1), Z=-6.307, P<0.001; No.11: median 1(0-2) vs. 0(0-1), Z=-5.895, P<0.001; No.12: median 1 (0-1) vs. 0 (0-1), Z=-6.693, P<0.001]. There was no significant difference in the number of positive lymph node between IU group and the conventional group(P>0.05), but the number of positive lymph nodes dissected in stage III patients of IU group was significantly higher than that in stage III patients of conventional group (14.6±4.8 vs. 14.0±3.6, t=2.531, P=0.011). The operative time of IU group was(272.0±12.0) minutes, which was significantly longer than (249.0±7.0) minutes of conventional group (t=14.638, P<0.001). However, with the increase of patients undergoing IU, the operation time of IU showed a downward trend. The average operation time of the last 20 patients was 264 minutes, and the average IU time was 15 minutes. CONCLUSIONS: Intraoperative ultrasound is more accurate N-staging of gastric cancer. Although increasing operation time, it is helpful for lymph node dissection in laparoscopic gastric cancer surgery, especially by providing good support for laparoscopic No.10, No.11 and No.12 lymph nodes dissection.