Corrigendum: Preclinical profiles of SKB264, a novel anti-TROP2 antibody conjugated to topoisomerase inhibitor, demonstrated promising antitumor efficacy compared to IMMU-132.

[This corrects the article DOI: 10.3389/fonc.2022.951589.].

Preclinical profiles of SKB264, a novel anti-TROP2 antibody conjugated to topoisomerase inhibitor, demonstrated promising antitumor efficacy compared to IMMU-132.

Purpose: The aim of this study was to improve the intratumoral accumulation of an antibody-drug conjugate (ADC) and minimize its off-target toxicity, SKB264, a novel anti-trophoblast antigen 2 (TROP2) ADC that was developed using 2-methylsulfonyl pyrimidine as the linker to conjugate its payload (KL610023), a belotecan-derivative topoisomerase I inhibitor. The preclinical pharmacologic profiles of SKB264 were assessed in this study. Methods: The in vitro and in vivo pharmacologic profiles of SKB264, including efficacy, pharmacokinetics-pharmacodynamics (PK-PD), safety, and tissue distribution, were investigated using TROP2-positive cell lines, cell-derived xenograft (CDX), patient-derived xenograft (PDX) models, and cynomolgus monkeys. Moreover, some profiles were compared with IMMU-132. Results: In vitro, SKB264 and SKB264 monoclonal antibody (mAb) had similar internalization abilities and binding affinities to TROP2. After cellular internalization, KL610023 was released and inhibited tumor cell survival. In vivo, SKB264 significantly inhibited tumor growth in a dose-dependent manner in both CDX and PDX models. After SKB264 administration, the serum or plasma concentration/exposure of SKB264 (conjugated ADC, number of payload units ≥1), total antibody (Tab, unconjugated and conjugated mAb regardless of the number of the payload units), and KL610023 in cynomolgus monkeys increased proportionally with increasing dosage from 1 to 10 mg/kg. The linker stability of SKB264 was significantly enhanced as shown by prolonged payload half-life in vivo (SKB264 vs. IMMU-132, 56.3 h vs. 15.5 h). At the same dose, SKB264's exposure in tumor tissue was 4.6-fold higher than that of IMMU-132. Conclusions: Compared with IMMU-132, the longer half-life of SKB264 had a stronger targeting effect and better antitumor activity, suggesting the better therapeutic potential of SKB264 for treating TROP2-positive tumors.

Natural cyclopeptide RA-V inhibits the NF-κB signaling pathway by targeting TAK1.

Rubiaceae-type cyclopeptides (RAs) are a type of plant cyclopeptides from the Rubia that have garnered significant attention owing to their unique bicyclic structures and amazing antitumour activities. Our recent work has shown that RAs suppress inflammation and angiogenesis and induce apoptosis. However, the underlying mechanism and targets remained unknown. Nuclear factor κB (NF-κB) signaling pathway plays a critical role in these biological processes, prompting us to investigate whether and how RAs affect this pathway. By screening compound libraries using NF-κB-dependent luciferase reporter, we observed that RA-V is the best NF-κB inhibitor. Further experiments demonstrated that RA-V interrupted the TAK1-TAB2 interaction and targeted TAK1 in this pathway. Moreover, RA-V prevented endotoxin shock and inhibited NF-κB activation and tumor growth in vivo. These findings clarify the mechanism of RA-V on NF-κB pathway and might account for the majority of known bioactivities of RA-V, which will help RA-V develop as new antiinflammatory and antitumour therapies.

Anti-arthritis effect of a novel quinazoline derivative through inhibiting production of TNF-α mediated by TNF-α converting enzyme in murine collagen-induced arthritis model.

TNF-α is a dominant inflammatory mediator in the pathogenesis of inflammatory diseases including rheumatoid arthritis. In our research, we discovered 2-chloro-N-(4-(2-morpholinoethoxy)phenyl)quinazolin-4-amine (9c) exhibited an outstanding anti-inflammatory activity on inhibiting TNF-α production with an IC50 of 8.86 µM in RAW264.7 cells. Interestingly, 9c had no effect on mRNA level of TNF-α but up-regulated the precursor of TNF-α (pro-TNF-α). Then, we studied TNF-α converting enzyme (TACE), which is the most important proteases responsible for the release of TNF-α from pro-TNF-α to soluble TNF-α. The results showed 9c reduced TACE both on the levels of mRNA and protein in a dose-dependent manner. In vivo study, collagen-induced arthritis (CIA) mice were treated by 9c orally. 9c exhibited significant anti-arthritis effect by ameliorating arthritic score, reducing inflammatory cell infiltration, protecting joints from destruction and decreasing the production of systemic TNF-α, IL-6, IL-1ß. The underlying mechanism of 9c on CIA was coincided with the in vitro, which was mediated by TACE. In conclusion, we discovered a novel quinazoline derivative which ameliorates arthritis through inhibiting production of TNF-α mediated by TACE for the first time.

Synthesis and biological evaluation of diarylthiazole derivatives as antimitotic and antivascular agents with potent antitumor activity.

By switching position of the N and S atom in the thiazole ring which were similar to the previously reported agent 5-(4-ethoxyphenyl)-4-(3',4',5'-trimethoxyphenyl)thiazol-2-amine, a series of 4,5-diarylthiazole derivatives were synthesized using Friedel-Crafts reaction based on chemical modification of Combrestatatin A-4 (CA-4). Their antiproliferative activities were evaluated and identified as new microtubule destabilizing agents. Structure-activity relationship study indicated that compound 8a with 3,4,5-trimethoxyphenyl group at the C-4 position and 4-ethoxyphenyl group at the C-5 position of 2-amino substituted thiazole was of the most potent inhibitory activity in this series. 8a was found to exhibit the IC50 values of 8.4-26.4nM in five human cancer cell lines, with comparable inhibition effects to CA-4. Moreover, 8a showed potency as a tubulin polymerization inhibitor, with colchicine site binding ability and comparable extent of inhibition against the growth of P-glycoprotein over-expressing multidrug resistant cell lines. Mechanism studies revealed that 8a could block the progression of cell cycle in the G2/M phase and result in cellular apoptosis in cancer cells. As a new tubulin destabilizing agent, 8a was also found high antivascular activity as it concentration-dependently reduced the cell migration and disrupted capillary like tube formation of HUVEC cells. Furthermore, 8a significantly suppressed the tumor growth in HCT116 and SK-OV-3 xenograft models with tumor growth inhibitory rate of 55.12% and 72.7%, respectively. Our studies highlighted that 8a was a promising microtubule targeting antitumor agent.

Synthesis and biological evaluation of 4-oxoquinoline-3-carboxamides derivatives as potent anti-fibrosis agents.

Thirty-one 4-oxoquinoline-3-carboxamides derivatives were synthesized and evaluated for their anti-fibrotic activities by the inhibition of TGF-ß1-induced total collagen accumulation and anti-inflammatory activities by the inhibition of LPS-stimulated TNF-α production. Among them, three compounds (10a, 10l and 11g) exhibited potent inhibitory effects on both TGF-ß1-induced total collagen accumulation and LPS-stimulated TNF-α production. Furthermore, oral administrations of 10l at a dose of 20 mg/kg/day for 4 weeks effectively alleviated lung inflammation and injury, and decreased lung collagen accumulation in bleomycin-induced pulmonary fibrosis model. Histopathological evaluation of lung tissue confirmed 10l as a potential, orally active agent for the treatment of pulmonary fibrosis.

Synthesis and lipid-lowering evaluation of 3-methyl-1H-purine-2,6-dione derivatives as potent and orally available anti-obesity agents.

Obesity accompanied with metabolic disorder is often complicated with a strong link of dyslipidemia and insulin resistance, whose indicator is the excess accumulation of triglycerides (TG) in cells. Consideration the idea of lipid-lowering and improving insulin resistance, 34 novel compounds by combination the xanthine scaffold with the chain of Rosiglitazone have been synthesized. Among them, several compounds showed efficiency on reducing TG in 3T3-L1 adipoctyes, and 11c exhibited the most optimal capacity in lipid-lowering and improving obese clinical symptoms in DIO mice. Furthermore, the hydrochloride of 11c (11c·HCl) showed excellent bioavailability, 58.94%, over 2 folds than that (28.03%) of 11c, and the anti-obesity effect of 11c·HCl at 50 mg/kg dose was better than that of Metformin at 150 mg/kg dose in DIO mice, almost reversed HFD to a normal level. Thus, 11c·HCl might be a potent and orally available anti-obesity agent via alleviating the obese clinical symptoms, body fat, improving serum parameters and insulin resistance and TG clearance in liver.

Synthesis and biological evaluation of tert-butyl-5-methylpyrimidin-piperazine derivatives as anti-obesity agents.

A series of tert-butyl-5-methylpyrimidin-piperazine derivatives were synthesized and their anti-obesity activities were evaluated. Compounds 4g and 5j were found to have significant effects in down-regulating the triglyceride level of 3T3-L1 adipocytes. 5j exhibited remarkable therapeutic effects on the diet-induced obesity (DIO) mouse model at 20 mg kg(-1) day(-1) for 4 weeks by decreasing the weights of body, liver, and fat. 5j also regulated serum biomarkers to appropriate ranges, exerted therapeutic activity of steatosis in liver tissue and ameliorated the obese-related symptoms. In addition, 5j significantly decreased the blood glucose levels in oral glucose tolerance tests and improved the insulin sensitivity in insulin tolerance tests. These results suggest that 5j could be a candidate for obesity treatment.