2026-03-11T21:53:28Z https://kagawa-u.repo.nii.ac.jp/oai

oai:kagawa-u.repo.nii.ac.jp:00000316 2024-10-31T08:00:06Z 13:40

Lemongrass essential oil and citral inhibit Src/Stat3 activity and suppress the proliferation/survival of small-cell lung cancer cells, alone or in combination with chemotherapeutic agents Maruoka, Takayuki 丸岡, 敬幸 マルオカ, タカユキ lemongrass essential oil citral small-cell lung cancer Src signal transducer and activator of transcription 3 chemotherapeutic agents chemotherapy combination therapy 香川大学 Kagawa University 博士（医学） Abstract Small-cell lung cancer (SCLC) is intractable due to its high propensity for relapse. Novel agents are thus needed for SCLC treatment. Lemongrass essential oil (LG-EO) and its major constituent, citral, have been reported to inhibit the proliferation and survival of several types of cancer cells. However, the precise mechanisms through which LG-EO and citral exert their effects on SCLC cells have not been fully elucidated. SCLC cells express Src and have high levels of Src-tyrosine kinase (Src-TK) activity. In most SCLC cell lines, constitutive phosphorylation of Stat3(Y705), which is essential for its activation, has been detected. Src-TK can phosphorylate Stat3(Y705), and activated Stat3 promotes the expression of the anti-apoptotic factors Bcl-xL and Mcl-1. In the present study, LG-EO and citral prevented Src-TK from phosphorylating Stat3(Y705), resulting in decreased Bcl-xL and Mcl-1 expression, in turn suppressing the proliferation/survival of SCLC cells. To confirm these findings, the wild-type-src gene was transfected into the LU135 SCLC cell line (LU135‑wt-src), in which Src and activated phospho-Stat3(Y705) were overexpressed. The suppression of cell proliferation and the induction of apoptosis by treatment with LG-EO or citral were significantly attenuated in the LU135-wt-src cells compared with the control LU135-mock cells. The signal transducer and activator of transcription 3 (Stat3) signaling pathway is also associated with intrinsic drug resistance. LU135-wt-src cells were significantly resistant to conventional chemotherapeutic agents compared with LU135-mock cells. The combined effects of citral and each conventional chemotherapeutic agent on SCLC cells were also evaluated. The combination treatment exerted additive or more prominent effects on LU135-wt-src, LU165 and MN1112 cells, which are relatively chemoresistant SCLC cells. These findings suggest that either LG-EO or citral, alone or in combination with chemotherapeutic agents, may be a novel therapeutic option for SCLC patients. doctoral thesis 2018-06-27 P application/pdf application/pdf application/pdf 甲第693号 https://kagawa-u.repo.nii.ac.jp/record/316/files/Med_A693.pdf https://kagawa-u.repo.nii.ac.jp/record/316/files/Med_A693_abstract.pdf https://kagawa-u.repo.nii.ac.jp/record/316/files/Med_A693_result.pdf https://kagawa-u.repo.nii.ac.jp/records/316 eng https://doi.org/10.3892/ijo.2018.4314 https://dl.ndl.go.jp/pid/11122965 29568932 500001070097 Copyright © Spandidos Publications 2018. open access