The Novel Benzothiazole Derivative PB11 Induces Apoptosis via the PI3K/AKT Signaling Pathway in Human Cancer Cell Lines

Benzothiazole-based apoptosis inducers: A comprehensive overview and future prospective

Cancer has become a major concern in healthcare globally, and over time, incidences and prevalence of cancer are increasing. To counter this, a lot of anticancer drugs are approved and are in clinical use, playing a pivotal role in its treatment. Due to drug resistance and adverse effects, a continuous demand for novel, potent, and safe candidates to treat cancer is always there. Over the last few decades, various heterocyclic ring-based derivatives have been explored and reported in the literature. In this regard, benzothiazole scaffold-based compound emerged as the versatile ring for developing novel and safe anticancer candidates. In this article, we have reported various benzothiazole heterocyclic ring-based derivatives demonstrating potent antiproliferative activity by induction of apoptosis via an intrinsic pathway in a dose-dependent manner. These compounds also displayed inhibition of different enzymes, for example, Aurora kinase, epidermal growth factor receptor, vascular endothelial growth factor receptor, phosphoinositide kinases, DNA topoisomerase, and tubulin polymerases. This study focused on a comprehensive overview of antiproliferative activity, structure-activity relationship, apoptosis induction activity, and enzyme inhibition by benzothiazole-based compounds.

Novel 2-Aminobenzothiazole Derivatives: Docking, Synthesis, and Biological Evaluation as Anticancer Agents

Sixteen novel 2-aminobenzothiazole compounds with different amines or substituted piperazine moieties were designed, synthesized, and tested using various methods. Potential interactions were assessed by docking new compounds in the adenosine triphosphate (ATP) binding domain of the PI3Kγ enzyme (PDB code: 7JWE) by nucleophilic substitution or solvent-free/neat fusion for docked compound synthesis. Final 2-aminobenzothiazole compounds were characterized by direct probe gas chromatography-mass spectrometry (GC-MS), proton (1H-NMR), carbon-13 (13C-NMR), and attenuated total reflectance-infrared Fourier transform infrared (ATR FT-IR). The synthesized compounds were investigated for anticancer activities on lung cancer (A549) and breast cancer (MCF-7) cell lines. The compounds' PI3Kγ inhibition was evaluated at a 100 μM concentration. 4-Nitroaniline and piperazine-4-nitroaniline combination in OMS5 and OMS14 reduced lung and breast cancer cell line growth. IC50 values for OMS5 and OMS14, the strongest compounds, ranged from 22.13 to 61.03 μM. OMS1 and OMS2 inhibited PI3Kγ at the highest rates (47 and 48%, respectively) at a 100 μM concentration. Results show that the PI3Kγ enzyme suppression is not the main mechanism behind these OMS5 and OMS14 anticancer effects. CDK2, Akt, mTOR, and p42/44 MAPK are affected. EGF receptor suppression matters. AKT1, AKT3, CDK1/cyclin B, PDK1 direct, PIK3CA E542 K/PIK3R1 (p110 α/p85 α), PIK3CD/PIK3R1 (p110 δ/p85 α), and PKN inhibition were measured to evaluate the possible mechanism of compound OMS14. PIK3CD/PIK3R1 (p110 δ/p85 α) is the most, with 65% inhibition, suggesting a possible mechanism of anticancer properties. Furthermore, the NCI 60-cell line inhibition demonstrates promising broad anticancer inhibition against numerous cancer cell lines of OMS5 and OMS14, which could be good lead compounds for future development.

Regorafenib induces Bim-mediated intrinsic apoptosis by blocking AKT-mediated FOXO3a nuclear export

Regorafenib (REGO) is a synthetic oral multi-kinase inhibitor with potent antitumor activity. In this study, we investigate the molecular mechanisms by which REGO induces apoptosis. REGO induced cytotoxicity, inhibited the proliferation and migration ability of cells, and induced nuclear condensation, and reactive oxygen species (ROS)-dependent apoptosis in cancer cells. REGO downregulated PI3K and p-AKT level, and prevented FOXO3a nuclear export. Most importantly, AKT agonist (SC79) not only inhibited REGO-induced FOXO3a nuclear localization and apoptosis but also restored the proliferation and migration ability of cancer cells, further demonstrating that REGO prevented FOXO3a nuclear export by deactivating PI3K/AKT. REGO treatment promotes Bim expression via the FOXO3a nuclear localization pathway following PI3K/AKT inactivation. REGO induced Bim upregulation and translocation into mitochondria as well as Bim-mediated Bax translocation into mitochondria. Fluorescence resonance energy transfer (FRET) analysis showed that REGO enhanced the binding of Bim to Bak/Bax. Knockdown of Bim, Bak and Bax respectively almost completely inhibited REGO-induced apoptosis, demonstrating the key role of Bim by directly activating Bax/Bak. Knockdown of Bax but not Bak inhibited REGO-induced Drp1 oligomerization in mitochondria. In conclusion, our data demonstrate that REGO promotes apoptosis via the PI3K/AKT/FOXO3a/Bim-mediated intrinsic pathway.