Targeting 4-1BB for tumor immunotherapy from bench to bedside

Immune dysfunction has been proposed as a factor that may contribute to disease progression. Emerging evidence suggests that immunotherapy aims to abolish cancer progression by modulating the balance of the tumor microenvironment. 4-1BB (also known as CD137 and TNFRS9), a member of tumor necrosis factor receptor superfamily, has been validated as an extremely attractive and promising target for immunotherapy due to the upregulated expression in the tumor environment and its involvement in tumor progression. More importantly, 4-1BB-based immunotherapy approaches have manifested powerful antitumor effects in clinical trials targeting 4-1BB alone or in combination with other immune checkpoints. In this review, we will summarize the structure and expression of 4-1BB and its ligand, discuss the role of 4-1BB in the microenvironment and tumor progression, and update the development of drugs targeting 4-1BB. The purpose of the review is to furnish a comprehensive overview of the potential of 4-1BB as an immunotherapeutic target and to discuss recent advances and prospects for 4-1BB in cancer therapy.

Changes in the esophagogastric junction outflow obstruction manometric feature based on the Chicago Classification updates

BACKGROUND

The critical diagnostic criteria for esophagogastric junction outflow obstruction (EGJOO) were published in the latest Chicago Classification version 4.0 (CCv4.0). In addition to the previous criterion [elevated integrated relaxation pressure (IRP) in supine position], manometric diagnosis of EGJOO requires meeting the criteria of elevated median-IRP during upright wet swallows and elevated intrabolus pressure. However, with the diagnostic criteria modification, the change in manometric features of EGJOO remained unclear.

AIM

To evaluate the esophageal motility characteristics of patients with EGJOO and select valuable parameters for confirming the diagnosis of EGJOO.

METHODS

We performed a retrospective analysis of 370 patients who underwent high-resolution manometry with 5 mL water swallows × 10 in supine, × 5 in upright position and the rapid drink challenge (RDC) with 200 mL water from November 2016 to November 2021 at Peking University First Hospital. Fifty-one patients with elevated integrated supine IRP and evidence of peristalsis were enrolled, with 24 patients meeting the updated manometric EGJOO diagnosis (CCv4.0) as the EGJOO group and 27 patients not meeting the updated EGJOO criteria as the isolated supine IRP elevated group (either normal median IRP in upright position or less than 20% of supine swallows with elevated IBP). Forty-six patients with normal manometric features were collected as the normal high-resolution manometry (HRM) group. Upper esophageal sphincter (UES), esophageal body, and lower esophageal sphincter (LES) parameters were compared between groups.

RESULTS

Compared with the normal HRM group, patients with EGJOO (CCv4.0) had significantly lower proximal esophageal contractile integral (PECI) and proximal esophageal length (PEL), with elevated IRP on RDC (P < 0.05 for each comparison), while isolated supine IRP elevated patients had no such feature. Patients with EGJOO also had more significant abnormalities in the esophagogastric junction than isolated supine IRP elevated patients, including higher LES resting pressure (LESP), intrabolus pressure, median supine IRP, median upright IRP, and IRP on RDC (P < 0.05 for each comparison). Patients with dysphagia had significantly lower PECI and PEL than patients without dysphagia among the fifty-one with elevated supine IRP. Further multivariate analysis revealed that PEL, LESP, and IRP on RDC are factors associated with EGJOO. The receiver-operating characteristic analysis showed UES nadir pressure, PEL, PECI, LESP, and IRP on RDC are parameters supportive for confirming the diagnosis of EGJOO.

CONCLUSION

Based on CCv4.0, patients with EGJOO have more severe esophagogastric junction dysfunction and are implicated in the proximal esophagus. Additionally, several parameters are supportive for confirming the diagnosis of EGJOO.

Tegaserod inhibits noxious rectal distention induced responses and limbic system c-Fos expression in rats with visceral hypersensitivity

AIM: To examine the effects of tegaserod, a serotonin (5-HT) 4 receptor partial agonist, on abdominal withdrawal reflex (AWR) to rectal distention (RD) and c-Fos expression in limbic system.

METHODS: Neonatal Sprague-Dawley rats randomly received colonic irritation by acetic acid from postnatal day 8 to day 21 as a visceral hypersensitive model (group H) or by intrarectal saline as a control group (group C). When they became adults, rectal distention (RD) was performed by a balloon (6F; Fogarty arterial embolectomy catheter; length, 20 mm; diameter, 2 mm) which was rapidly inflated with increasing volumes of saline (0.4, 0.8 and 1.2 mL) for 20 s at five-minute intervals. Five subgroups of group H (H-saline, H-vehicle, H-Teg0.1, H-Teg0.3 and H-Teg1.0) were injected randomly with saline, vehicle (1-methyl-2-thpyrrolidone) or tegaserod at doses of 0.1, 0.3 and 1.0 mg/kg ip, respectively. Two subgroups of group C (C-Saline and C-Teg1.0) were injected with saline or tegaserod (1.0 mg/kg) ip. RD was performed 10 min after injection, AWR was recorded and c-Fos expression in limbic system was analyzed quantitatively by immunohistochemistry.

RESULTS: Compared to saline, tegaserod significantly inhibited AWR in group H (0.4 mL: from 2.0 to 0.5; 0.8 mL: from 3.5 to 1.5; 1.2 mL: from 4.0 to 3.0, P < 0.01), but had no significant effect on group C. Tegaserod dose-dependently attenuated the number of c-Fos positive neurons in limbic structures, anterior cingulate cortex (ACC) showed the greatest attenuation. In group H, tegaserod (1.0 mg/kg) resulted in a significant overall decrease to 57% of H-saline (283 ± 41 vs 162 ± 16, P < 0.01), in ACC to 42% of H-saline (72 ± 10 vs 31 ± 8, P < 0.01). In group C, tegaserod (1.0 mg/kg) resulted in an overall decrease to 77% of C-saline (214 ± 13 vs 164 ± 22, P < 0.01), in ACC to 65% of C-saline (48 ± 8 vs 31 ± 7, P < 0.01).

CONCLUSION: Tegaserod inhibits the response to rectal distention in rats with visceral hypersensitivity and dose-dependently attenuates c-Fos expression in limbic system, especially in anterior cingulate cortex.

[The hemolytic site of the basic phospholipase A(2) from Agkistrodon halys pallas]

The gene of the basic phospholipase A(2) from Agkistrodon halys Pallas (BPLA(2) )was mutated site-directedly by polymerase chain reaction (PCR) and the residue Arg(34) of the encloding protein was substituted by Glu and Gln respectively. The mutant gene has been cloned into the expression vector pBLMVL2 and has been expressed in E.coli RR1 effectively. The protein was produced as insoluble inclusion bodies. After partial purification, the inclusion bodies were denatured and renatured into active form, and the renatured recombinant protein was purified by gel-filtration. The expression product has the same enzymatic activity as the denatured-refolded BPLA(2) and its hemolytic activity dropped distinctly, which suggest that the basic residue Arg(34) of BPLA(2) is a crucial amino acid residue during the process of hemolysis.