Rectal cancer is a malignant gastrointestinal tumor, which is associated with high morbidity and mortality. High‑mobility group protein 1 (HMGB1) is widely present in the nucleus of eukaryotic cells, and is highly conserved between humans and rodents. Recently, HMGB1 has been reported to be involved in the progression and metastasis of human cancer; however, its role in the development and metastasis of human rectal cancer remains unclear. The present study detected the expression levels of HMGB1 in pathological specimens from patients with clinically identified rectal cancer using immunohistochemistry and western blotting. The results demonstrated that HMGB1 was highly expressed in samples from patients with rectal cancer. The positive rate of HMGB1 in rectal cancer tissues was 96.08% (49/51), which was significantly higher compared with 3.92% (2/51) in normal tissues. In addition, western blotting indicated that HMGB1 was distributed and located not only in the nucleus, but also in the cytoplasm of colorectal cancer cells. HMGB1‑specific short hairpin (sh)RNA was used to silence the endogenous expression of HMGB1 in colorectal cancer cells. A functional assay demonstrated that knockdown of endogenous HMGB1 expression significantly inhibited the proliferation of SW620 and Colo320 cells. Furthermore, western blotting revealed that knockdown of endogenous HMGB1 expression contributed to activation of caspase‑3 and the substrate poly (ADP‑ribose) polymerase. The expression levels of B‑cell lymphoma 2 (Bcl‑2) and Bcl‑2‑associated X protein (Bax) were also detected by western blotting. As expected, decreased levels of Bcl‑2 and increased levels of Bax were detected in the HMGB1 shRNA‑transfected colorectal cancer cells, and the Bax/Bcl‑2 ratio was increased in HMGB1 shRNA‑transfected cells. These data indicated that HMGB1 may act as an oncogene in rectal cancer, and knockdown of endogenous HMGB1 expression may significantly inhibit the proliferation of colorectal cancer cells and promote apoptosis of tumor cells. Further research regarding the mechanisms underlying the effects of HMGB1 on the progression of rectal cancer may provide novel targets for the treatment of rectal cancer, and provide a theoretical reference for clinical treatment.
The aim was to develop a slow-release poly-lactic-coglycolic acid (PLGA)-oxaliplatin microsphere and to assess the therapeutic effectiveness and safety of this preparation on colorectal tumor in vivo. The PLGA-oxaliplatin microsphere was prepared based on a spray-drying method, and the drug loading and in-vitro oxaliplatin release profile were carried out using high performance liquid chromatography. The inhibiting effect on tumor growth was examined using in-vivo subcutaneously inoculated colorectal tumor models of nude mice. The size of the microsphere was less than 100 microm, drug loading was 18-22% and drug release time lasted as long as 30 days. PLGA-oxaliplatin microspheres significantly restrained tumor growth and this effect correlated with decreased expression of proliferating cell nuclear antigen and increased expression of terminal deoxynucleotidyltransferase dUTP nick end labeling in tumor cells. Bodyweight measurement and blood analysis did not suggest significant adverse effects on the mice during the study. The PLGA-oxaliplatin microsphere developed here was suitable for regional use; it appears safe and effective in controlling the tumor growth. This preparation shows promise in reducing local recurrence of colorectal cancer after resection, but needs further investigation.
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