Overcoming multi-drug resistance in SCLC: a synergistic approach with venetoclax and hydroxychloroquine targeting the lncRNA LYPLAL1-DT/BCL2/BECN1 pathway
- Mol Cancer. 2024 Oct 31;23(1):243. doi: 10.1186/s12943-024-02145-1.
- 1. School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China.
- 2. Laboratory for Clinical Medicine, Capital Medical University, Beijing, 100069, China.
- 3. Beijing Key Laboratory of Cancer Invasion and Metastasis Research, Beijing, 100069, China.
- 4. Department of Medical Oncology, Beijing Chest Hospital, Beijing Tuberculosis and Thoracic Tumor Research Institute, Capital Medical University, Beijing, 101149, China.
- 5. Department of Gastrointestinal Surgery/Clinical Nutrition, Capital Medical University Affiliated Beijing Shijitan Hospital, Beijing, 100038, China.
- 6. School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China. [email protected].
- 7. Laboratory for Clinical Medicine, Capital Medical University, Beijing, 100069, China. [email protected].
- 8. Beijing Key Laboratory of Cancer Invasion and Metastasis Research, Beijing, 100069, China. [email protected].
- # Contributed equally.
Background: Small cell lung Cancer (SCLC) stands as one of the most lethal malignancies, characterized by a grim diagnosis and prognosis. The emergence of multi-drug resistance poses a significant hurdle to effective therapy. Although previous studies have implicated the long noncoding RNA LYPLAL1-DT in the tumorigenesis of SCLC, the precise role of the highly expressed LYPLAL1-DT in SCLC chemoresistance and the underlying mechanism remain inadequately understood.
Methods: cDDP-, VP-16- and PTX-resistant SCLC cells lines were established. The viabilities of SCLC cells were assessed by CCK-8 assay in vitro and xenograft tumor formation assay in vivo. Apoptosis was evaluated by FACS, Western blot and JC-1 fluorescence staining, while Autophagy was explored via autophagic flux detection under confocal microscopy and autophagic vacuole investigation under transmission electron microscopy (TEM). The functional role and mechanism of LYPLAL1-DT were further investigated by gain- and loss-of-function assays in vitro. Furthermore, the therapeutic efficacy of the combination of venetoclax and HCQ with cDDP, VP-16 or PTX was evaluated by cell line, cell-derived xenograft (CDX) and patient-derived xenograft (PDX) mice model.
Results: Our findings revealed that LYPLAL1-DT is upregulated in chemoresistant SCLC cell lines. Gain- and loss-of-function assays demonstrated that LYPLAL1-DT impairs sensitivity to cDDP, VP-16, or PTX both in vitro and in vivo. Overexpression of LYPLAL1-DT significantly enhanced Autophagy and inhibited Apoptosis in SCLC cells. Further analyses, including RIP and RNA pull-down assays, revealed that LYPLAL1-DT promotes the expression of BCL2 by sponging miR-204-5p and is implicated in the assembly of the autophagy-specific complex (BECN1/PtdIns3K complex). Combining venetoclax and HCQ with cDDP, VP-16, or PTX effectively mitigated chemoresistance in SCLC cells and suppressed tumor growth in CDX and PDX models without inducing obvious toxic effects.
Conclusions: Our findings demonstrate that upregulation of LYPLAL1-DT sequesters Apoptosis through the LYPLAL1-DT/miR-204-5p/BCL2 axis and promotes Autophagy by facilitating the assembly of the BECN1/PtdIns3K complex, thereby mediating multi-drug resistance of SCLC. The triple combination of venetoclax, HCQ, in conjunction with cDDP, VP-16 or PTX overcomes refractory SCLC, shedding light on a potential therapeutic target for combating SCLC chemoresistance.