Antiproliferative and apoptosis-inducing activity of schisandrin B against human glioma cells.

BACKGROUND: Malignant glioma is the most devastating and aggressive tumour in the brain and is characterised by high morbidity, high mortality and extremely poor prognosis. The main purpose of the present study was to investigate the effects of schisandrin B (Sch B) on glioma cells both in vitro and in vivo and to explore the possible anticancer mechanism underlying Sch B-induced apoptosis and cell cycle arrest. METHODS: The anti-proliferative ability of Sch B on glioma cells were assessed by MTT and clony formation assays. Flow cytometric analysis was used to detect cell cycle changes. Apoptosis was determined by Hoechst 33342 staining and annexin V/PI double-staining assays. The mitochondrial membrane potential was detected by Rhodamine 123 staining. The in vivo efficacy of Sch B was measured using a U87 xenograft model in nude mice. The expressions of the apoptosis-related and cell cycle-related proteins were analysed by western blot. Student's t-test was used to compare differences between treated groups and their controls. RESULTS: We found that Sch B inhibited growth in a dose- and time-dependent manner as assessed by MTT assay. In U87 and U251 cells, the number of clones was strongly suppressed by Sch B. Flow cytometric analysis revealed that Sch B induced cell cycle arrest in glioma cells at the G0/G1 phase. In addition, Sch B induced glioma cell apoptosis and reduced mitochondrial membrane potential (ΔΨm) in a dose-dependent manner. Mechanically, western blot analysis indicated that Sch B induced apoptosis by caspase-3, caspase-9, PARP, and Bcl-2 activation. Moreover, Sch B significantly inhibited tumour growth in vivo following the subcutaneous inoculation of U87 cells in athymic nude mice. COCLUSIONS: In summary, Sch B can reduce cell proliferation and induce apoptosis in glioma cells and has potential as a novel anti-tumour therapy to treat gliomas.

[Inhibitory effect of adenovirus-mediated D2S gene plus bromocriptine therapy on primary cultures of human non-functioning pituitary adenoma cells].

OBJECTIVE: To explore the inhibitory effect of non-functioning pituitary adenoma (NFPA) cells after a combined treatment of adenovirus mediated D2S gene and bromocriptine in vitro. METHODS: Adenovirus containing dopamine 2 receptor short isoform (D2S) gene was used to infect NFPA cells. The transfection of D2S gene into NFPA cells was confirmed by immunofluorescence. And cell apoptosis of infected cells treated by bromocriptine was evaluated with CCK-8 assay in vitro. RESULTS: When D2S gene transfection and bromocriptine was used in combination, the survival rate of NFPA cells significantly decreased (40 ± 5)% versus the control group (97 ± 5)% and the pAd-EGFP transfection combined bromocriptine treatment group (90 ± 9)% (P < 0.05). CONCLUSION: The combined treatment of adenovirus-mediated D2S gene and bromocriptine can effectively induce the apoptosis of NFPA cells on primary culture and increase the sensitivity of NFPA to dopamine agonist.

[Natural history study of postoperative residual non-functioning pituitary adenomas].

OBJECTIVE: To observe the postoperative residual non-functioning pituitary adenomas (PR-NFPAs) without postoperative radiotherapy and to analyze the natural history of PR-NFPAs' growth in order to provide a basis for selecting appropriate strategies of clinical treatment. METHODS: We evaluated the natural history of 20 patients with PR-NFPAs who did not receive postoperative radiotherapy and drug therapy. Through MRI images, the residual tumor volumes of those patients were serially measured. We further calculated the monthly growth rate and the tumor volume doubling time (TVDT) and analyzed the correlations between the patient age, gender, volume of residual tumor, cavernous sinus (CS) invasion and TVDT. RESULTS: All patients received observation alone. Among which, 17 adenomas increased in volume and 3 remained unchanged during a follow-up period of 7 months to 17 years (mean 3.90 yr). The mean patient age was 41.8 years. As to 17 patients with tumor regrowth, the tumor volume at the beginning of MRI observation period was 4.73 cm(3) and tumor volume at the last MRI observation was 16.98 cm(3). During the mean 4-year follow-up period, the average monthly growth rate of PR-NFPAs was 7.87% and the mean TVDT was 724 days. Such factors as patient age, gender, volume of residual tumor and CS invasion did not affect the TVDT of PR-NFPAs. CONCLUSION: The tumor growth rate of PR-NFPAs is not significantly correlated with the patient gender, age, volume of residual tumor and CS invasion. In conjunctions with the volume of PR-NFPAs and the distance between residual adenoma and optic chiasm, we should take the TVDT into consideration and determine the appropriate and safe follow-up period.

Expression of D2RmRNA isoforms and ERmRNA isoforms in prolactinomas: correlation with the response to bromocriptine and with tumor biological behavior.

Invasive prolactinomas are more likely to be resistant to drug therapy but the mechanism of this is still unknown. The objective of this study was to analyze the different expression of ERmRNA and D2RmRNA isoforms in prolactinomas responsive and resistant to dopamine agonist (DA), and to discuss the correlation of such gene expression with tumor biological behavior. A prospective study of 20 consecutive patients who harbored prolactinomas was designed. Patients were classified as responsive (14 cases) or resistant (six cases) according to their clinical and biochemical response to bromocriptine. Tumor tissue samples were examined by means of QRT-PCR analysis. Median D2SmRNA expression in responsive patients was about 2.5-fold that in resistant ones (13.5 +/- 10.4 and 5.4 +/- 2.4, respectively, P = 0.09). No significant difference was found between D2LmRNA expression levels (P = 0.77). However, there was a significant difference between D2S/D2LmRNA ratios for responsive and resistant tumors (P = 0.012). A significant difference was not found between these two groups in levels of ERalphamRNA and ERbetamRNA expression (P = 0.20 and 0.06, respectively). D2SmRNA expression was significantly different for invasive and noninvasive tumors (6.2 +/- 3.6 vs. 17.0 +/- 11.2, respectively, P = 0.02). The D2S/D2L ratio is related to the responsiveness of prolactinomas to DA medication, in which D2SmRNA plays an important role. Lower expression of D2SmRNA in invasive tumor patients suggests that invasive prolactinomas may be more likely to be resistant to DA medication.

Five years follow-up of invasive prolactinomas with special reference to the control of cavernous sinus invasion.

BACKGROUND: Few data are presently available on the effective control of cavernous sinus (CS) invasion of invasive prolactinomas. The aim of this retrospective study, through a mean period of 5 years follow up, is to observe the tumor shrinkage of CS invasive prolactinomas, as well as PRL normalization with bromocriptine therapy. METHODS: 68 patients met the criteria of invasive prolactinomas (Grade III or IV in the classification scheme of Knosp and colleagues; serum PRL level greater than 200 ng/ml). 33 patients underwent bromocriptine therapy as the initial treatment, and 14 of these 33 had combined treatment with microsurgery and/or radiotherapy. The other 35 patients received microsurgery as the primary treatment, after which two patients had normal PRL without taking bromocriptine and other 33 patients received bromocriptine treatment after microsurgery. RESULTS: Tumor volume on magnetic resonance images had completely disappeared in 50 patients (74%), while all the other 18 patients had residual tumor in the parasellar areas, invading the CS, and 14 patients had a secondary empty sella due to tumor shrinkage. Of those 14 patients, seven still had elevated PRL levels; five had optic chiasmal herniation by different degrees (P < 0.05). There were 49 patients with normal PRL levels (72%); five patients with PRL levels more than 200 ng/ml. After the treatment, 14 patients with tumor volume disappearance on MR images and PRL normalization therefore withdrew from bromocriptine therapy. During a subsequent one-and-a-half-year follow-up, tumor recurrence and PRL increase were not found in those 14 patients. Twenty-seven patients maintained normal PRL levels with low-dose bromocriptine, of which 20 patients had their tumor disappear while seven patients had CS residual tumor. CONCLUSIONS: About three-fourths of prolactinomas with CS invasion can be effectively controlled not only with regard to tumor volume disappearance but also in serum PRL normalization. Residual tumor in the CS areas with PRL normalization and no pressure symptoms can be treated with low-dose of bromocriptine so as to achieve long-term tumor volume control and endocrine control. Great attention should be paid to CS residual tumors accompanying the empty sella, especially in cases with optic chiasmal herniation.

Bromocriptine treatment of invasive giant prolactinomas involving the cavernous sinus: results of a long-term follow up.

OBJECT: The aim of this study was to observe long-term clinical outcomes in a group of patients treated with bromocriptine for invasive giant prolactinomas involving the cavernous sinus. METHODS: Data from 20 patients with invasive giant prolactinomas at the authors' institutions between July 1997 and June 2004 were retrospectively reviewed. The criteria to qualify for study participation included: (1) tumor diameter greater than 4 cm, invading the cavernous sinus to an extent corresponding to Grade III or IV in the classification scheme of Knosp and colleagues; (2) serum prolactin (PRL) level greater than 200 ng/ml; and (3) clinical signs of hyperprolactinemia and mass effect. Among the 20 patients who met the criteria, six had undergone unsuccessful transcranial or transsphenoidal microsurgery prior to bromocriptine treatment and 14 patients received bromocriptine as the primary treatment. Eleven of the 20 patients underwent adjuvant radiotherapy. After a mean follow-up period of 37.3 months, the clinical symptoms in all patients improved by different degrees. Tumor volume on magnetic resonance images was decreased by a mean of 93.3%. In 11 patients, the tumor had almost completely disappeared; in the other nine patients, residual tumor invaded the cavernous sinus. Visual symptoms improved in 13 of the patients who had presented with visual loss. Eight patients had normal PRL levels. The postoperative PRL level was more than 200 ng/ml in seven patients. During the course of drug administration, cerebrospinal fluid leakage occurred in one patient, who subsequently underwent transsphenoidal surgery. No case of apoplexy occurred during bromocriptine treatment. CONCLUSIONS: Dopamine agonist medications are effective as a first-line therapy for invasive giant prolactinomas, because they can significantly shrink tumor volume and control the PRL level. Tumor mass vanishes in some patients after bromocriptine treatment; in other patients with localized residual tumor, stereotactic radiosurgery is a viable option so that unnecessary surgery can be avoided. The application of radiotherapy does not reliably shrink tumor volume.