Ethanolic extract of gabirobeira (Campomanesia adamantium) leaves reduces proliferation of osteosarcoma cells in vitro

Osteosarcoma is the most commonly diagnosed malignant bone tumor in humans, with a higher incidence in children and young people. It is highly aggressive and has a high metastatic potential. Its treatment is based on both chemotherapy and surgical intervention. However, currently used chemotherapeutic agents, such as doxorubicin, have several adverse effects on the patient. Therefore, there is a growing demand for new chemotherapeutic agents that stimulate new researches, such as those involving compounds extracted from plants, such as the gabirobeira. In this study, we aimed to evaluate the cytotoxic effects of ethanolic extract, both crude and ethyl acetate, of gabirobeira leaves on osteosarcoma cells in vitro. Cytotoxicity was evaluated using the Trypan blue exclusion method and the IC50 values were calculated using the tetrazolium reduction method. The ethanolic extract of gabirobeira leaves showed a cytotoxic effect on osteosarcoma cells in vitro. The group treated with the crude extract at 1. 0& 956;L mL-1 concentration for 48 hours showed higher cytotoxicity and the lowest IC50 value for this extract was found in the 24 to 48 hours interval. The ethanolic extract of gabirobeira leaves is cytotoxic for osteosarcoma cells.

Expression of p53 protein, PCNA, and Ki-67 in osteosarcomas of bone

Expressions of p53 protein, a product of the tumor suppressor gene were studied in osteosarcomas relating to various prognostic factors. Thirty-four osteosarcomas were investigated immunohistochemically with a monoclonal antibody clone PAb240, which recognizes a common conformational epitope of mutant p53 proteins and another clone PAb1801, which reacts with both wild- and mutant-type p53 proteins. The results were compared with expressions of proliferating cell nuclear antigen (PCNA) and Ki-67 providing a simple method for the assessment of growth fractions of tumors. PAb240 stained nuclei and cytoplasm of tumor cells in 8 of 34 osteosarcomas (23.5%), whereas PAb1801 reacted in all 34 osteosarcomas (100%). Fifteen tumors (44.1%) showed positivity for PAb1801 in more than half of the tumor cells. Twelve patients were alive and thirteen were dead. Tumors from 9 patients (75%) who survived revealed only focal positive immunoreactions with PAb1801 and tumors from 6 patients (46.1%) who died revealed diffuse reactions. Twelve cases (35.3%) showed a high PCNA index (> 40%) and fibroblastic osteosarcomas revealed the highest PCNA positivity. Twenty-two cases (64.7%) revealed a very low Ki-67 index (less than 10%) and Ki-67 index showed a good correlation with PCNA positivity (r = 0.6247). Expressions of both wild-and mutant-type p53 protein, PCNA, and Ki-67 were not correlated with other clinical or pathological parameters.

Osteocalcin expression in primary bone tumors: in situ hybridization and immunohistochemical study

Osteocalcin is one of the most abundant noncollagenous proteins found in adult bone. It is a highly conserved gamma-carboxyglutamic acid-containing protein that is believed to be produced exclusively by osteoblasts. In this study, intracellular and extracellular localization of osteocalcin in osteosarcoma was examined with anti-osteocalcin antibody and in situ hybridization using a synthetic oligonucleotide. Immunohistochemically, osteoblastic osteosarcomas were all positive for osteocalcin. The chondroblastic osteosarcomas were positive on the neoplastic chondrocytes. The five fibroblastic osteosarcomas out of seven were positive for osteocalcin immunostaining over the neoplastic spindle cells. Five cases of osteoblastic osteosarcomas out of seven were positive for osteocalcin in situ hybridization. Two cases of chondroblastic osteosarcomas and three cases of fibroblastic osteosarcomas were positive for in situ demonstration of osteocalcin. The malignant tumor giant cells were positive for osteocalcin immunostaining 83%. They were also positive for in situ hybridization. The benign giant cells in five giant cell tumors and five aneurysmal bone cysts were negative for osteocalcin immunostaining. The benign giant cells in three chondroblastoma and three Paget's disease were positive for osteocalcin. In this study, the osteocalcin in situ hybridization and immunostaining has very important meaning for making differential diagnoses of, especially giant cell rich bone forming tumors.