RESUMEN
The aim of the present study was to present a retrospective review of 42 metastatic colorectal cancer (mCRC) patients treated using the XELIRI regimen as second-line chemotherapy during the period between 2010 and 2012. Patients were treated with capecitabine, 1,600 (≥65 years) or 2,000 mg/m2 (<65 years), on days 1-15, 200 mg/m2 irinotecan (CPT-11) on day 1, with or without 7.5 mg/kg bevacizumab on day 1 and every 21 days. A total of 21 patients underwent XELIRI and 21 underwent XELIRI plus bevacizumab treatment. Fifteen patients received continuous administration of bevacizumab in the first- and second-line settings [bevacizumab beyond progression (BBP)+], whereas 27 patients did not receive the treatment (BBP-). Forty patients (95.2%), including all the patients in the BBP+ group, received sequentially administered XELOX and XELIRI regimens from the first- to the second-line setting. The disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and adverse events were compared between the BBP- and BBP+ groups. The median relative dose intensity was similar (93.9% for capecitabine and 96.3% for CPT-11 in the BBP- group vs. 94.8% for capecitabine and 91.5% for CPT-11 in the BBP+ group). The DCR was 25.9% in the BBP- and 66.6% in the BBP+ groups (P=0.020). The median PFS was 3.5 months in the BBP- and 7.2 months in the BBP+ groups (P=0.028). The BBP+ group exhibited a higher median OS time compared to the BBP- group (12.5 months in the BBP- group vs. not reached in the BBP+ group; P=0.0267). The most common grade 3/4 adverse event (n≥20) was hypertension observed in the BBP+ group [three patients (20%)]: these three patients were well-controlled with a single antihypertensive drug. Treatment with sequentially administered XELOX and XELIRI regimens did not aggravate adverse events in the 40 patients. The results showed that the XELIRI regimen, involving continuous treatment with bevacizumab, was well-tolerated and effective as a second-line chemotherapy and sequentially administering XELOX and XELIRI was feasible and manageable for patients with mCRC.
RESUMEN
The Pleckstrin and Sec7 domain-containing (PSD) gene, which regulates skeletal rearrangements, has been found to be more frequently methylated both in ulcerative colitis (UC)-associated colorectal cancer tissues (5 of 7; 71.4%) and matched normal epithelia (4 of 7; 57.1%) compared to non-neoplastic UC epithelia (6 of 22; 27.3%) and sporadic colorectal cancer tissues (6 of 32; 18.8%). The levels of PSD mRNA were positively correlated with the methylation status of PSD, as shown by both MSP and bisulfite sequencing. To determine the potential role of PSD silencing in the mechanisms underlying UC-associated carcinogenesis, the levels of senescence, proliferation and apoptosis were evaluated in a normal human fibroblast cell line (NHDF) in which 93% of PSD expression was knocked down by a small-interfering RNA (si-RNA). Although there were no significant differences in the levels of senescence and proliferation caused by PSD knockdown, the level of apoptosis was significantly decreased by PSD knockdown (5.3% in siControl-treated cells vs. 0.67% in siPSD-treated cells, p=0.0001). In addition, reactive oxygen species inducers accelerated apoptosis in NHDF and a neutrophil-like cell line, which was significantly reduced by PSD knockdown. To verify the effect of PSD methylation in tissue sections including 21 samples from UC patients with or without tumors, we elucidated PSD promoting accumulation of filamentous-actin (F-actin) and apoptosis by immunohistochemistry and TUNEL assay, respectively. Both levels of accumulation of F-actin and apoptosis were significantly decreased in specimens from UC patients with PSD methylation compared to those without PSD methylation (F-actin: 0.69±0.86 with vs. 1.57±0.51 without, p=0.0031, apoptotic index: 0.31±0.63 with vs. 1.0±0.88 without, p=0.0277). In conclusion, our results indicate that PSD methylation plays a significant role in the mechanisms underlying UC-associated carcinogenesis through its inhibitory effect on apoptosis in the interaction between colorectal mucosa and neutrophils.