Arecoline is the primary alkaloid in betel nuts, which are known as a risk factor for oral submucosal fibrosis and oral cancer. Lung cancer is a severe type of carcinoma with high cell motility that is difficult to treat. However, the detailed mechanisms of the correlation between Arecoline and lung cancer are not fully understood. Here, we investigated the effect of Arecoline on migration in lung cancer cell lines and its potential mechanism through the muscarinic acetylcholine receptor 3 (mAChR3)-triggered EGFR/Src/FAK pathway. Our results indicate that different concentrations of Arecoline treatment (10 µM, 20 µM, and 40 µM) significantly increased the cell migration ability in A549 and CL1-0 cells and promoted the formation of the filamentous actin (F-actin) cytoskeleton, which is a crucial element for cell migration. However, migration of H460, CL1-5, and H520 cell lines, which have a higher migration ability, was not affected by Arecoline treatment. The EGFR/c-Src/Fak pathway, which is responsible for cell migration, was activated by Arecoline treatment, and a decreased expression level of E-cadherin, which is an epithelial marker, was observed in Arecoline-treated cell lines. Blockade of the EGFR/c-Src/Fak pathway with the inhibitors of EGFR (Gefitinib) or c-Src (Dasatinib) significantly prevented Arecoline-promoted migration in A549 cells. Gefitinib or Dasatinib treatment significantly disrupted the Arecoline-induced localization of phospho-Y576-Fak during focal adhesion in A549 cells. Interestingly, Arecoline-promoted migration in A549 cells was blocked by a specific mAChR3 inhibitor (4-DAMP) or a neutralizing antibody of matrix metalloproteinase (MMP7 or Matrilysin). Taken together, our findings suggest that mAChR3 might play an essential role in Arecoline-promoted EGFR/c-Src/Fak activation and migration in an A549 lung cancer cell line.

Immunotherapy targeting immune checkpoints (ICPs), such as programmed death‐ligand‐1 (PD‐L1), is used as a treatment option for advanced or metastatic non‐small cell lung cancer (NSCLC). However, overall response rate to anti‐PD‐L1 treatment is limited due to antigen heterogeneity and the immune‐suppressive tumor microenvironment. Human leukocyte antigen‐G (HLA‐G), an ICP as well as a neoexpressed tumor‐associated antigen, is previously demonstrated to be a beneficial target in combination with anti‐PD‐L1. In this study, a nanobody‐based trispecific T cell engager (Nb‐TriTE) is developed, capable of simultaneously binding to T cells, macrophages, and cancer cells while redirecting T cells toward tumor cells expressing PD‐L1‐ and/or HLA‐G. Nb‐TriTE shows broad spectrum anti‐tumor effects in vitro by augmenting cytotoxicity mediated by human peripheral blood mononuclear cells (PBMCs). In a humanized immunodeficient murine NSCLC model, Nb‐TriTE exhibits superior anti‐cancer potency compared to monoclonal antibodies and bispecific T cell engagers. Nb‐TriTE, at the dose with pharmacoactivity, does not induce additional enhancement of circulating cytokines secretion from PMBCs. Nb‐TriTE effectively prolongs the survival of mice without obvious adverse events. In conclusion, this study introduces an innovative therapeutic approach to address the challenges of immunotherapy and the tumor microenvironment in NSCLC through utilizing the dual ICP‐targeting Nb‐TriTE.

Cyclin-dependent kinase 5 (CDK5) is a unique member of the cyclin-dependent kinase family. CDK5 is activated by binding with its regulatory proteins, mainly p35, and its activation is essential in the development of the central nervous system (CNS) and neurodegeneration. Recently, it has been reported that CDK5 plays important roles in regulating various biological and pathological processes, including cancer progression. Concerning prostate cancer, the androgen receptor (AR) is majorly involved in tumorigenesis, while CDK5 can phosphorylate AR and promotes the proliferation of prostate cancer cells. Clinical evidence has also shown that the level of CDK5 is associated with the progression of prostate cancer. Interestingly, inhibition of CDK5 prevents prostate cancer cell growth, while drug-triggered CDK5 hyperactivation leads to apoptosis. The blocking of CDK5 activity by its small interfering RNAs (siRNA) or Roscovitine, a pan-CDK inhibitor, reduces the cellular AR protein level and triggers the death of prostate cancer cells. Thus, CDK5 plays a crucial role in the growth of prostate cancer cells, and AR regulation is one of the important pathways. In this review paper, we summarize the significant studies on CDK5-mediated regulation of prostate cancer cells. We propose that the CDK5–p35 complex might be an outstanding candidate as a diagnostic marker and potential target for prostate cancer treatment in the near future.

Chemotherapy, in combination with immune checkpoint blockade (ICB) targeting to programmed death‐1 (PD‐1) or its ligand PD‐L1, is one of the first‐line treatments for patients with advanced non–small‐cell lung cancer (NSCLC). However, a large proportion of patients, especially those with PD‐L1 negative tumors, do not benefit from this treatment. This may be due to the existence of multiple immunosuppressive mechanisms other than the PD‐1/PD‐L1 axis. Human leukocyte antigen‐G (HLA‐G) has been identified as an immune checkpoint protein (ICP) and a neoexpressed tumor‐associated antigen (TAA) in a large proportion of solid tumors. In this study, we evaluated the induction of HLA‐G as well as PD‐L1 using sublethal doses of chemotherapeutics including pemetrexed in different NSCLC cell lines. Except for gefitinib, most of the chemotherapeutic agents enhanced HLA‐G and PD‐L1 expression in a dose‐dependent manner, whereas pemetrexed and carboplatin treatments showed the most consistent upregulation of PD‐L1 and HLA‐G in each cell line. In addition to protein levels, a novel finding of this study is that pemetrexed enhanced the glycosylation of HLA‐G and PD‐L1. Pemetrexed potentiated the cytotoxicity of cytotoxic T lymphocytes (CTLs) to treat NSCLC. Both in vitro and in vivo experiments revealed that CTL‐mediated cytotoxicity was most pronounced when both anti‐PD‐L1 and anti‐HLA‐G ICBs were combined with pemetrexed treatment. In conclusion, anti‐HLA‐G could be an intervention strategy in addition to the anti‐PD‐1/PD‐L1 pathway for NSCLC. Moreover, dual targeting of PD‐L1 and HLA‐G combined with pemetrexed might have a better extent of CTL‐based immunotherapy.

Medullary thyroid cancer (MTC) is a neuroendocrine tumor that arises from the parafollicular C-cells, which produces the hormone calcitonin. RET is a transmembrane receptor protein-tyrosine kinase, which is highly expressed in MTC. Our previous studies reported that cyclin-dependent kinase 5 (CDK5) plays a crucial role in cancer progression, including MTC. However, the role of CDK5 in GDNF-induced RET signaling in medullary thyroid cancer proliferation remains unknown. Here, we investigated RET activation and its biochemically interaction with CDK5 in GDNF-induced medullary thyroid cancer proliferation. Our results demonstrated that GDNF stimulated RET phosphorylation and thus subsequently resulted in CDK5 activation by its phosphorylation. Activated CDK5 further caused STAT3 activation by its specific phosphorylation at Ser727. Moreover, we also found that GDNF treatment enhanced ERK1/2 and EGR1 activity, which is involved in p35 activation. Interestingly, we identified for the first time that CDK5 physically interacted with RET protein in MTC. Overall, our results provide a new mechanism for medullary thyroid cancer cell proliferation, suggesting that targeting CDK5 may be a promising therapeutic candidate for human medullary thyroid cancer in the near future.