RESUMEN
Background/purpose: Proliferation-associated protein 2G4 (PA2G4) has alternative transcriptional and translational initiation. One dominant transcript ENST00000303305 could be translated into two protein isoforms (PA2G4-P42 and PA2G4-P48). In this study, we aimed to explore the effects of PA2G4-P42 and PA2G4-P48 on the proliferation of head and neck squamous cell carcinoma (HNSCC) and the mechanisms regulating PA2G4-P48 stability. Materials and methods: HNSCC cell lines HSC2 and SCC25 with relatively low PA2G4 expression were used for in-vitro cell studies. PA2G4-P42 and PA2G4-P48 overexpression lentiviruses were generated. In vitro cell proliferation was assessed by CCK-8 and colony formation. In vivo tumor cell proliferation was assessed by HSC2 cell-derived xenograft tumors. Liquid chromatography-mass spectrometry (LC-MS)/MS and co-immunoprecipitation (co-IP) assays were applied to check PA2G4-P48 interacting partners. Cycloheximide (CHX) chase and ubiquitin-based co-IP assays were also performed. Results: PA2G4-P48 was the dominant isoform, with substantially higher expression than PA2G4-P42 in HNSCC. PA2G4-P48 overexpression enhanced HNSCC cell proliferation, but PA2G4-P42 overexpression slowed the proliferation. MCTS1 interacted with PA2G4-P48, but not PA2G4-P42. PA2G4 protein but not its mRNA expression was decreased in cells with MCTS1 knockdown. MG132 treatment abrogated this alteration. MCTS1 overexpression significantly elevated the half-life of PA2G4-P48, while its knockdown drastically reduced the half-life compared with the control cells. In addition, MCTS1 overexpression significantly decreased the polyubiquitination of exogenous flag-tagged PA2G4-P48. MCTS1 overexpression-induced cell proliferation was hampered by knocking down of PA2G4-P48. Conclusion: PA2G4-P42 and PA2G4-P48 exert growth-suppressive and growth-promoting effects in HNSCC, respectively. MCTS1 can interact with PA2G4-P48 and prolong its half-life by reducing its poly-ubiquitination.
RESUMEN
Background/purpose: High SEC61 translocon subunit gamma (SEC61G) expression is associated with an unfavorable prognosis in patients with head and neck squamous cell carcinoma (HNSCC), but the underlying mechanisms remain poorly understood. Materials and methods: HNSCC representative cell lines SCC15 and CAL27 were used to explore the regulation of SEC61G on Ca2+ leak from the endoplasmic reticulum (ER). Ca2+-activated autophagy was monitored by fluorescent labeling of autophagosomes and western blotting assays. CSC marker expression, sphere formation, colony formation, and transwell of invasion were detected to investigate the role of SEC61G in regulating cancer-stem cell (CSC) properties. Results: Among the SEC61 complex genes, only SEC61G upregulation is consistently associated with unfavorable progression-free interval and disease-specific survival in patients with HNSCC. Low-dose cisplatin (CDDP) treatment induced SEC61G upregulation in SCC15 and CAL27 cells. SEC61G knockdown significantly impaired CDDP-induced Ca2+ from the ER and the phosphorylation of ERK1/2 and AMPK. CDDP-induced autophagy in HNSCC cells were hampered by SEC61G shRNA, in terms of impaired autophagosome formation, lowered LC3-II/GAPDH ratio and restored p62 expression. CDDP-induced CSC properties, including CSC marker expression, sphere formation, colony formation, and invasive capabilities could be suppressed by shSEC61G and chloroquine, a specific autophagy inhibitor. Conclusion: Findings of this study revealed the contribution of SEC61G in promoting cisplatin-induced CSC properties of HNSCC cells via promoting Ca2+-mediated autophagy.
RESUMEN
OBJECTIVE: To investigate the change of zygomatic and temporal soft tissue after coronal incision. METHODS: A retrospective analysis was performed in 33 patients who received firm fixation for unilateral zygomatic comminuted fracture through semi-coronal incision. All the patients were followed up for more than one year. Craniofacial anthropometric measurement through 3D-CT reconstruction and facial profile was performed. The difference between the operated side and healthy side was analyzed. RESULTS: At the temporal concave point, the soft tissue thickness at healthy side was (1.60 +/- 0. 97) mm more than that at operated side, showing a significant difference between them (P < 0.01). While the soft tissue thickness was not statistically different between two sides at zygion, malar prominence, zygomaxillare, and temporal convex point (P > 0.05). CONCLUSIONS: The soft tissue atrophy may happen at temporal fat pad after semi-coronal incision, but not at zygomatic area. Intraoperative precise dissection and less stretch of soft tissue may be helpful to avoid the postoperative facial asymmetry.