Altered Mitochondrial Cytochrome b Gene Expression during the Regression of Hemangioma

Abstract

Hemangioma is a primary tumor of microvasculature. Its development typically exhibits a proliferative phase followed by an involuting phase that continues into the involuted phase. Although apoptosis has been reported, the mechanisms regulating the spontaneous regression of hemangioma are largely unknown. The authors recently demonstrated up-regulation of the mitochondrial cytochrome b gene in hemangioma associated with steroid-induced regression. The present study investigated whether a similar change occurred during spontaneous regression. Biopsy material was obtained from 11 patients with hemangiomas at different phases of development. In one of these patients, a biopsy was taken from the proliferative, involuting, and involuted areas of the hemangioma. In another patient, a biopsy was taken before and 5 weeks after the intralesional administration of steroids. From each tissue specimen, RNA was isolated and subjected to reverse transcriptase-polymerase chain reaction analysis by use of specific primers for the human mitochondrial cytochrome b gene. Semiquantitative reverse transcriptase-polymerase chain reaction analysis revealed that the strongest expression of the mitochondrial cytochrome b transcripts was in specimens taken from hemangiomas in the involuting phase compared with those from the proliferative and involuted phases. The authors concluded that mitochondrial cytochrome b is associated with both the spontaneous and the steroid-induced regression of hemangioma, probably by regulating apoptosis.

Effects of five commonly used glucocorticoids on haemangioma in vitro¶

“…Mitochondrial genes have been associated with cell senescence and are proposed to play an important role in apoptosis 11 . We have recently reported alterations to the transcription of mitochondrial cytochrome (cyt) b in spontaneous and triamcinolone‐induced regression of haemangioma 12,13 . We have also demonstrated upregulation of clusterin/apoliproprotein J (clust/apoJ) in spontaneous regression of haemangioma 14 .…”

Spontaneous Tumour Regression

“…There are also reports of an up-regulated expression of the gene coding for mitochondrial cytochrome b (Hasan et al, 2001)(. Modulation of the electron transport chain could serve as an explanation as to why the cells undergo apoptosis (Bruckner & Frieden 2003).…”

Patología y patogénesis de los hemangiomas

“…Sin embargo la causa de que este fenómeno se inicie y progrese no es bien conocida. Se ha propuesto que el aumento en la transcripción del gen del citocromo mitocondrial b, detectado en la fase involutiva de hemangiomas, bien espontáneos o inducidos por corticosteroides, jugaría un papel desencadenante de la apoptosis por modulación de la actividad de la cadena respiratoria 16 . La clusterina/Aopj, marcador de apoptosis, se expresa intensamente en las células endoteliales y los mastocitos de los hemangiomas en involución e involucionados.…”