Cytokine-mediated antitumor effect of bacillus Calmette-Gu�rin on tumor cells in vitro

Abstract

Intravesical instillation therapy of bacillus Calmette-Guérin (BCG) is a useful modality for recurrent superficial transitional-cell carcinoma (TCC) of the urinary bladder. The mechanism of BCG effect has not yet been well characterized. BCG was tested in vitro for cytokine-mediated antiproliferative activity against T24 and KK47 cells (cell lines established from human TCC of the urinary bladder), and ACHN cells (cell line established from human renal cell carcinoma) using a modified human tumor clonogenic assay. Continuous exposure of cells to BCG at concentrations of more than 5 micrograms/ml in the presence of peripheral blood mononuclear cells (PBMC) consisting of a mixture of 5 x 10(4) monocytes/dish and 5 x 10(5) lymphocytes/dish, obtained from healthy donors, significantly inhibited colony formation of T24 and ACHN cells in comparison with growth inhibition in the absence of PBMC (P < 0.05). Slightly inhibited colony formation was observed with KK47 cells under the same conditions. At the same time various cytokines were measured in supernatants when BCG and the same conditioned PBMC were co-cultured. Tumor necrosis factor alpha (TNF alpha) and interleukin-1 beta (IL-1 beta) were detected at markedly high levels at 24 h, and interferon gamma (IFN gamma) was detected at 120 h. IL-2 and macrophage-colony-stimulating factor were not detected. Neutralizing anti-TNF alpha monoclonal antibody significantly reduced the anti-proliferative activity of ACHN cells, and anti-IFN gamma antibody reduced that of T24 cells. The results obtained suggest that cytokines mediated by BCG play an important role in the antitumor activity of BCG and that the sensitivity of bladder cancer cells to the cytokines induced by BCG may differ considerably.

Cytotoxic Effect of BCG on Tumor Cells Viewed in Cytokine Activities Induced in Vitro

“…The mechanism of antitumor activity of BCG for transitional cell Carcinoma of the urinary bladder has not yet been well characterized. It was demonstrated in our previous study using various established cell lines in vitro that a large part of the antitumor activity of BCG is due to a direct action of TNF alpha and IFN gamma mediated by BCG [7]. And also each cell line had different sensitivities to cytokines such as TNF alpha and IFN gamma.…”

“…Samples of 10 ml heparinized peripheral blood were obtained from the patients. Blood samples were prepared by the methods described elsewhere [7]. In this study, separations into monocytes and lymphocytes was not performed.…”

“…It has been reported that cytokines, such as tumor necrosis factor (TNF), interferon (IFN) gamma, interleukin-1 (IL-1), and interleukin-2 (IL-2), are present in urine following intravesical immunotherapy with BCG [5,6]. It was suggested that cytokines mediated by BCG play an important role in the antitumor activity of BCG and that the sensitivity of bladder cancer cells to the cytokines mediated by BCG may differ considerably [7]. The Akt.…”

Ερευνητική Μελέτη Της Τοπικής Απάντησης Σε Επιφανειακό Καρκίνο Της Ουροδόχου Κύστης Μετά Από Χορήγηση Ανοσοτροποποιητικών Παραγόντων

“…Εξετάζοντας την Οµάδα Β, που έλαβε συνδυασµό BCG και IFN-α, σε σύγκριση µε την Οµάδα Α, που έλαβε µονοθεραπεία µε BCG, βρέθηκε ότι τα επίπεδα IFN-γ ούρων ήταν γενικά χαµηλότερα και µάλιστα ότι η διαφορά υπέρ της Οµάδας Α ήταν στατιστικά σηµαντική στην 5 η έγχυση. Αυτό το εύρηµα δείχνει, ότι η ελάττωση των δόσεων BCG συνοδεύεται και από αντίστοιχη ελάττωση των επιπέδων IFN-γ, αφού -όπως έχει εκτενώς αναλυθεί-το BCG αποτελεί ισχυρότατο επαγωγέα της έκκρισης της κυτταροκίνης αυτής 372,417,427 . Επιπλέον, οι µεταβολές των συγκεντρώσεων IFN-γ σε σχέση µε την 1 η έγχυση ήταν σταθερά υψηλότερες σε όλες τις εγχύσεις στην Οµάδα Α σε σχέση µε τη Β και η διαφορά αυτή ήταν στατιστικά σηµαντική στην 3 η , 5 η και 6 η έγχυση.…”