Deviation of Trypsin Activity Using Peptide Conformational Imprints.

In this study, a methodology utilizing peptide conformational imprints (PCIs) as a tool to specifically immobilize porcine pancreatic alpha-trypsin (PPT) at a targeted position is demonstrated. Owing to the fabrication of segment-mediated PCIs on the magnetic particles (PCIMPs), elegant cavities complementary to the PPT structure are constructed. Based on the sequence on targeted PPT, the individual region of the enzyme is trapped with different template-derived PCIMPs to show certain types of inhibition. Upon hydrolysis, N-benzoyl-L-arginine ethyl ester (BAEE) is employed to assess the hydrolytic activity of PCIMPs bound to the trypsin using high-performance liquid chromatography (HPLC) analysis. Further, the kinetic data of four different PCIMPs are compared. As a result, the PCIMPs presented non-competitive inhibition toward trypsin, according to the Lineweaver-Burk plot. Further, the kinetic analysis confirmed that the best parameters of PPT/PCIMPs 233-245+G were Vmax = 1.47 × 10-3 mM s-1, Km = 0.42 mM, kcat = 1.16 s-1, and kcat/Km = 2.79 mM-1 s-1. As PPT is bound tightly to the correct position, its catalytic activities could be sustained. Additionally, our findings stated that the immobilized PPT could maintain stable activity even after four successive cycles.

Minimally invasive surgery alone compared with intensity-modulated radiotherapy for primary stage I nasopharyngeal carcinoma.

BACKGROUND: The National Comprehensive Cancer Network guidelines recommend intensity-modulated radiotherapy (IMRT) as the primary curative treatment for newly diagnosed nasopharyngeal carcinoma (NPC), but the radiation-related complications and relatively high medical costs remain a consequential burden for the patients. Endoscopic nasopharyngectomy (ENPG) was successfully applied in recurrent NPC with radiation free and relatively low medical costs. In this study, we examined whether ENPG could be an effective treatment for localized stage I NPC. METHODS: Ten newly diagnosed localized stage I NPC patients voluntarily received ENPG alone from June 2007 to September 2017 in Sun Yat-sen University Cancer Center. Simultaneously, the data of 329 stage I NPC patients treated with IMRT were collected and used as a reference cohort. The survival outcomes, quality of life (QOL), and medical costs between two groups were compared. RESULTS: After a median follow-up of 59.0 months (95% CI 53.4-64.6), no death, locoregional recurrence, or distant metastasis was observed in the 10 patients treated with ENPG. The 5-year overall survival, local relapse-free survival, regional relapse-free survival, and distant metastasis-free survival among the ENPG-treated patients was similar to that among the IMRT-treated patients (100% vs. 99.1%, 100% vs. 97.7%, 100% vs. 99.0%, 100% vs. 97.4%, respectively, P > 0.05). In addition, compared with IMRT, ENPG was associated with decreased total medical costs ($ 4090.42 ± 1502.65 vs. $ 12620.88 ± 4242.65, P < 0.001) and improved QOL scores including dry mouth (3.3 ± 10.5 vs. 34.4 ± 25.8, P < 0.001) and sticky saliva (3.3 ± 10.5 vs. 32.6 ± 23.3, P < 0.001). CONCLUSIONS: ENPG alone was associated with promising long-term survival outcomes, low medical costs, and satisfactory QOL and might therefore be an alternative strategy for treating newly diagnosed localized stage I NPC patients who refused radiotherapy. However, the application of ENPG should be prudent, and prospective clinical trials were needed to further verify the results.

Neoadjuvant chemotherapy followed by concurrent chemoradiotherapy versus concurrent chemoradiotherapy alone in locoregionally advanced nasopharyngeal carcinoma: A phase III multicentre randomised controlled trial.

BACKGROUND: The role of neoadjuvant chemotherapy (NACT) for locoregionally advanced nasopharyngeal carcinoma (NPC) is unclear. We aimed to evaluate the feasibility and efficacy of NACT followed by concurrent chemoradiotherapy (CCRT) versus CCRT alone in locoregionally advanced NPC. METHODS: Patients with stage III-IVB (excluding T3N0-1) NPC were randomly assigned to receive NACT followed by CCRT (investigational arm) or CCRT alone (control arm). Both arms were treated with 80 mg/m2 cisplatin every 3 weeks concurrently with radiotherapy. The investigational arm received cisplatin (80 mg/m2 d1) and fluorouracil (800 mg/m2 civ d1-5) every 3 weeks for two cycles before CCRT. The primary end-point was disease-free survival (DFS) and distant metastasis-free survival (DMFS). Secondary end-point was overall survival (OS). Survival curves for the time-to-event endpoints were analyzed by the Kaplan-Meier method and compared using the log-rank test. The P value was calculated using the 5-year endpoints. RESULTS: Four hundred seventy six patients were randomly assigned to the investigational (n = 238) and control arms (n = 238). The investigational arm achieved higher 3-year DFS rate (82.0%, 95% CI = 0.77-0.87) than the control arm (74.1%, 95% CI = 0.68-0.80, P = 0.028). The 3-year DMFS rate was 86.0% for the investigational arm versus 82.0% for the control arm, with marginal statistical significance (P = 0.056). However, there were no statistically significant differences in OS or locoregional relapse-free survival (LRRFS) rates between two arms (OS: 88.2% versus 88.5%, P = 0.815; LRRFS: 94.3% versus 90.8%, P = 0.430). The most common grade 3-4 toxicity during NACT was neutropenia (16.0%). During CCRT, the investigational arm experienced statistically significantly more grade 3-4 toxicities (P < 0.001). CONCLUSION: NACT improved tumour control compared with CCRT alone in locoregionally advanced NPC, particularly at distant sites. However, there was no early gain in OS. Longer follow-up is needed to determine the eventual therapeutic efficacy.

Neoadjuvant chemotherapy plus intensity-modulated radiotherapy versus concurrent chemoradiotherapy plus adjuvant chemotherapy for the treatment of locoregionally advanced nasopharyngeal carcinoma: a retrospective controlled study.

BACKGROUND: In the era of intensity-modulated radiotherapy (IMRT), the role of neoadjuvant chemotherapy (NAC) for locoregionally advanced nasopharyngeal carcinoma (NPC) is under-evaluated. The aim of this study was to compare the efficacy of NAC plus IMRT and concurrent chemoradiotherapy (CCRT) plus adjuvant chemotherapy (AC) on locoregionally advanced NPC. METHODS: Between January 2004 and December 2008, 240 cases of locoregionally advanced NPC confirmed by pathologic assessment in Sun Yat-sen University Cancer Center were reviewed. Of the 240 patients, 117 received NAC followed by IMRT, and 123 were treated with CCRT plus AC. The NAC + IMRT group received a regimen that included cisplatin and 5-fluorouracil (5-FU). The CCRT + AC group received cisplatin concurrently with radiotherapy, and subsequently received adjuvant cisplatin and 5-FU. The survival rates were assessed by Kaplan-Meier analysis, and the survival curves were compared using a log-rank test. Multivariate analysis was conducted using the Cox proportional hazard regression model. RESULTS: The 5-year overall survival (OS), locoregional relapse-free survival (LRRFS), distant metastasis-free survival (DMFS), and disease-free survival (DFS) were 78.0, 87.9, 79.0, and 69.8%, respectively, for the NAC + IMRT group and 78.7, 84.8, 76.2, and 65.6%, respectively, for the CCRT + AC group. There were no significant differences in survival between the two groups. In multivariate analysis, age (<50 years vs. ≥50 years) and overall stage (III vs. IV) were found to be independent predictors for OS and DFS; furthermore, the overall stage was a significant prognostic factor for DMFS. Compared with the CCRT + AC protocol, the NAC + IMRT protocol significantly reduced the occurrence rates of grade 3-4 nausea-vomiting (6.5 vs. 1.5%, P = 0.023) and leukopenia (9.7 vs. 0.8%, P = 0.006). CONCLUSIONS: The treatment outcomes of the NAC + IMRT and CCRT + AC groups were similar. Distant metastasis remained the predominant mode of treatment failure.