Alteration in TWIST expression: possible role in paclitaxel-induced apoptosis in human laryngeal carcinoma Hep-2 cell line.

AIM: To explore the relationship between alteration in the expression of TWIST, highly conserved transcription factor from the basic helix-loop-helix family, and apoptosis of Hep-2 cells induced by chemotherapeutic agent paclitaxel. METHODS: Morphological changes of Hep-2 cells were observed by acridine orange cytochemistry staining. Viability of Hep-2 cells treated with various concentrations of paclitaxel was examined by cell proliferation assay. Apoptosis was examined by flow cytometry. The mRNA and protein expression of TWIST in response to paclitaxel at 24 hours, 48 hours, and 72 hours was examined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively. RESULTS: Typical morphological changes of apoptotic cells at 24 hours, 48 hours, or 72 hours after treatment wiyth paclitaxel (10x10(-9) mol/L) were observed. The cell survival rates significantly decreased in a concentration- and time-dependent manner (P=0.001). Paclitaxel-induced apoptosis increased with culture time (22.6+/-5.3% after 24 hours, 38.7+/-7.9% after 48 hours, and 52.4+/-14.3% after 72 hours; P=0.002). Both mRNA and protein expression of TWIST was markedly decreased at both mRNA levels and protein levels, at 24 hours, 48 hours, and 72 hours in the paclitaxel-induced apoptosis of Hep-2 cells (P<0.001). CONCLUSION: TWIST, which has a significantly decreased expression in response to paclitaxel in Hep-2 cells, may play a pivotal role in paclitaxel-induced apoptosis of Hep-2 cells.

[Clinical analysis of small cell neuroendocrine carcinoma of the head and neck].

OBJECTIVE: To seek a best therapeutic protocol for small cell neuroendocrine carcinoma of head and neck. METHODS: The clinical data of 34 patients with small cell neuroendocrine carcinoma of head and neck, 21 males and 13 females, aged 53 (17 - 71), were retrospectively analyzed. The therapeutic protocols that had been used for the patients included surgery alone (in 5 patients), radiotherapy alone (in 7 patients), combined therapy with surgery and radiotherapy (in 7 patients), combined therapy with surgery and chemotherapy (for 3 patients), combined therapy with radiotherapy and chemotherapy (for 10 patients), and combined therapy with surgery, radiotherapy and chemotherapy (for 2 patients). The follow-up ended on August 1 2007. RESULTS: The prognosis of the patient with small cell neuroendocrine carcinoma of skin was the best. Local recurrence occurred in 7 patients, of which 2 underwent surgery alone, 2 combined therapy with surgery and radiotherapy, 1 combined therapy with surgery and chemotherapy, and 2 combined therapy with radiotherapy and chemotherapy. Recurrence in neck occurred in 1 patient that had undergone combined therapy with surgery and radiotherapy. Neck lymph node metastasis was found in 4 patients of whom 2 had undergone surgery alone, 1 had undergone combined therapy with surgery and chemotherapy, and 1 combined therapy with radiotherapy and chemotherapy. Distant metastasis was found in 11 patients of whom 2 had undergone surgery alone, 2 radiotherapy alone, 3 combined therapy with surgery and radiotherapy, and 3 combined therapy with radiotherapy and chemotherapy. The median survival time was 24 months, and the overall 3-year and 5-year cumulative survival rates were 65.37% and 35.95% respectively. CONCLUSION: The prognosis of the patient with small cell neuroendocrine carcinoma of head and neck was poor. Small cell neuroendocrine carcinoma cases with the lesions at different sites differ in prognosis and needed different therapeutic fashions. Combined therapy with radiotherapy and chemotherapy is recommended for small cell neuroendocrine carcinoma of head and neck, and surgery serves as a salvage therapeutic measure.

Down-regulation of TWIST decreases migration and invasion of laryngeal carcinoma Hep-2 cells by regulating the E-cadherin, N-cadherin expression.

PURPOSE: The transcription factor TWIST is an important factor in regulation of the epithelial-mesenchymal transition (EMT), which represents the primary stages during the metastasis of tumors. To identify the role of TWIST in the regulation of metastasis in laryngeal carcinoma Hep-2 cells, we investigated whether the alteration of TWIST has an effect on the Hep-2 cells morphology and whether the alteration of TWIST has an effect on the expression of E-cadherin, N-cadherin as well as the ability of cell motion, migration, and invasion. METHODS: Morphological changes of Hep-2 cells that were transfected a mircoRNA against TWIST vector were observed by the reserved microscope. Reverse transcription-polymerase chain reaction was performed in order to examine the mRNA expression of TWIST, E-cadherin, and N-cadherin. Western blotting was performed to examine the protein expression of TWIST, E-cadherin, and N-cadherin. Cell motion ability was examined by Scratch-wound assay. Transwell(™) chamber assays were used to determine cell migration and invasion. RESULTS: Transfecting a mircoRNA down-regulated TWIST expression at mRNA and protein levels. Down-regulation of TWIST expression induced morphological changes, such as the inversion of the EMT. Moreover, down-regulation of TWIST expression up-regulated E-cadherin and down-regulated N-cadherin expressions at mRNA and protein levels, respectively. Furthermore, we confirmed that down-regulation of TWIST expression decreased the motion, invasion, and migration ability of the Hep-2 cells. CONCLUSIONS: Down-regulation of TWIST expression decreases migration and invasion of laryngeal carcinoma Hep-2 cells by regulation of the E-cadherin, N-cadherin expression.

[Tubed pectoralis major myocutaneous flap for reconstruction of circumference pharyngoesophageal defects].

OBJECTIVE: To investigate the feasibility and efficacy of tubed pectoralis major myocutaneous flap in the reconstruction of circumferential defects following resection for locally advanced hypopharyngeal and cervical esophageal carcinoma. METHODS: From Dec. 2004 to Oct. 2008, 30 patients underwent immediate reconstruction by tubed pectoralis major myocutaneous flap for circumferential defects following resection of primary tumours. Among them, 22 were hypopharyngeal carcinoma, 7 were cervical esophageal carcinoma and one was recurrent laryngeal carcinoma involved the hypopharyngeal lumen. Five of 30 patients had received previous radiotherapy and three had failed in the previous surgical procedure. In this series, 12 patients had total pharyngolaryngectomy and 18 had total pharyngolaryngectomy and partial cervical esophagectomy. RESULTS: Postoperative pharyngocutaneous fistula formation occurred in 4 patients, 2 of them with previous radiotherapy and 2 with diabetes, and the fistulae healed later. Two patients developed anastomotic strictures at the upper junction, but they had good responses to dilatation treatment and had satisfactory oral intake. The postoperative follow-up time ranged from 8 to 56 months. Median follow-up was 18 months. One-year survival rate was 71.4% and three-year survival rate was 42.5%. CONCLUSIONS: The tubed pectoralis major myocutaneous flap is a reliable procedure to reconstruct hypopharyngeal circumferential defects following resection of advanced hypopharyngeal and cervical esophageal carcinoma. This method may be the optimal choice for the reconstruction of hypopharyngeal circumferential defects following resection of recurrent carcinoma. The incidence of fistula and stenosis could be kept at an acceptable level.

[Role of TWIST in the apoptosis of Hep-2 cells induced by paclitaxel].

OBJECTIVE: To explore the relationship between the expression of transcription factor TWIST and apoptosis of Hep-2 cells induced by paclitaxel. METHODS: Morphological changes of Hep-2 cells were observed by reserved microscopy and acridine orange cytochemistry staining. Viability of Hep-2 cells treated with various concentrations of paclitaxel was detected by MTT assay. Apoptosis was examined by flow cytometry. The expressions of transcription factor TWIST at both mRNA and protein level in response to paclitaxel at 24 h, 48 h and 72 h were then examined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, respectively. RESULTS: Typical morphological changes of apoptotic cells, i.e., cellular rounding-up, cytoplasmic contraction, chromatin condensation and, particularly, apoptotic body, the main morphological characteristic of apoptosis, were observed by reserved microscopy and acridine orange cytochemistry staining. The cell surviving rates significantly decreased in a concentration- and time-dependent manner as evidenced by MTT assay (P < 0.05). Percent of apoptosis after 24 h, 48 h or 72 h paclitaxel-treatment was (22.6 +/- 5.3)%, (38.7 +/- 7.9)% and (52.4 +/- 14.3)%, respectively, whereas the percent of control was (9.85 +/- 5.83)%. There existed a statistically significant difference between treatment and control (F = 12.621, P < 0.05). The expression of TWIST at both mRNA and protein levels for 24 h, 48 h or 72 h in the paclitaxel-induced apoptosis of Hep-2 cells were decreased by 16.7%, 46.8%, 76.9% (F = 10.407, P < 0.05) and 16.4%, 33.6%, 69.6% (F = 18.013, P < 0.05) respectively. CONCLUSIONS: TWIST, which is significantly decreased in expression in response to paclitaxel in Hep-2 cells, may play a pivotal role in paclitaxel-induced apoptosis of Hep-2 cells.