Cytotoxic and cytostatic effects of the streptococcal preparation OK-432 and its subcellular fractions on human ovarian tumor cells

Mechanism of antitumor effect on mouse hepatocellular carcinoma by intratumoral injection of OK-432, a streptococcal preparation

Intratumoral (i.t.) injection of OK-432, a streptococcal preparation, into implanted tumors of mouse hepatocellular carcinoma (MIH-2) showed antitumor effect including tumor eradication. Intraperitoneal administration of same dose OK-432 did not exhibit tumor suppressive effect. In vitro cytotoxic test suggested that direct cytotoxic effect of OK-432 was not associated with antitumor activity by i.t.-OK-432 treatment. It was also found that Toll-like receptor 4 signaling was not involved in i.t.-OK-432 treatment. Three mice out of five, which had shown tumor eradication by i.t.-OK-432 treatment did not reject re-challenge of MIH-2 cells. Splenocytes from i.t.-OK-432 treated mice did not produce IFN-gamma by stimulation with MIH-2 cells in vitro, but produced abundant IFN-gamma by stimulation with OK-432. Immunofluorescence microscopy demonstrated that CD4+T cells, but not CD8+T cells, infiltrated to i.t.-OK-432 treated tumor tissue produced IFN-gamma. Tumor-infiltrating CD4+T cells from i.t.-OK-432 treated tumor tissue produced IFN-gamma by in vitro stimulation with OK-432 higher than those from untreated tumor tissue. IFN-gamma directly induced apoptosis of MIH-2 cells in vitro. Collectively, i.t.-OK-432 treatment induced priming of CD4+T cells to antigenecity of OK-432, and repetitive i.t.-OK-432 treatment induced IFN-gamma production from OK-432-sensitized CD4+T cells in tumor site, leading to apoptosis of MIH-2 cells susceptible to IFN-gamma.

Appraisal of transarterial immunoembolization for hepatocellular carcinoma: a clinicopathologic study

Recurrence of hepatocellular carcinoma (HCC) is frequent, even after apparently curative resection. Preoperative transcatheter arterial chemoembolization (TAE) does not improve disease-free survival after hepatic resection. We previously reported the potential usefulness of transarterial immunoembolization (TIE), a newly developed arterial embolization technique using OK-432 and fibrinogen, as preoperative treatment. In this study, we further investigated the effect of TIE by histologic examination of the resected specimens and compared it with conventional TAE in a prospective nonrandomized manner. Thirty-nine patients underwent TIE (n = 17) or TAE (n = 22) before curative hepatectomy for HCC. Transarterial immunoembolization was performed according to the standard protocol using OK-432, fibrinogen, and thrombin. Histologic changes in cancerous and noncancerous liver tissues were examined at different stages after TIE. Histologic grading of cancer cell injury according to the modified Shimosato criteria (Grades 0-IV, in increasing order of severity of cell injury) and postoperative disease-free survival were compared between the two groups. Based on the results of histopathology, TAE was more effective than TIE against the main tumor. In contrast, TIE was significantly more effective than TAE against extracapsular invasion and intrahepatic metastasis. Disease-free survival after hepatectomy tended to be better in patients pretreated with TIE than TAE. Postoperative tumor recurrences in the TIE group (n = 4) occurred in the nontreatment regions, whereas tumor recurrences in TAE group developed mostly (8 of 11 patients) in treated liver regions. Based on results of histologic examination, TIE seems to be more effective than conventional TAE against extracapsular invasion and intrahepatic metastasis. Data for disease-free survival and recurrence site suggest TIE may be a useful preoperative treatment.

Multi-institutional randomized clinical study on the comparative effects of intracavital chemotherapy alone versus immunotherapy alone versus immunochemotherapy for malignant effusion

The current prospective randomized study was designed to compare the effects of intracavitary (i.c.) chemotherapy vs immunotherapy vs immunochemotherapy for malignant effusion. Between 1992 and 1995, a total of 42 patients with malignant effusion were registered, and 41 patients were eligible for statistical analysis. The primary diseases of the eligible patients included 27 gastric, four colorectal, four pancreatic, three lung, two liver and one oesophageal cancers. The patients with malignant effusion were randomly assigned into one of three i.c. therapeutic regimens: chemotherapy alone with weekly injection of anticancer agents (ACAs: cisplatin, mitomycin-C, adriamycin, etc.) (Group A, n = 13); immunotherapy alone with weekly injection of streptococcal preparation OK-432 (Group B, n = 14); or immunochemotherapy with ACAs and OK-432 (Group C, n = 14). The response of the effusion, patient survival and the kinetics of cytokines in the effusion were compared. There were no differences in the patients' backgrounds. The side-effects of the regimens included pain, anorexia, fever, leucopenia and anaemia and there were no differences in their incidence among the three groups. One patient died after cisplatin (CDDP) administration in Group A. Cytologic examination revealed that tumour cells in the effusion disappeared in 23% of Group A cases, 36% of Group B cases and 36% of Group C cases. The malignant effusion did not disappear in any of the Group A cases; however, the effusion disappeared in 29% of Group B cases and 43% of Group C cases (P = 0.03, Group A vs Group C). Furthermore, the 50% survival period was 1.6 months for Group A, 2.4 months for Group B and 3.5 months for Group C. The 6-month survival rate was 7% for Group A, 6% for Group B and 34% for Group C, and the 1-year survival rate was 0%, 0% and 17% respectively (P = 0.048, Group A vs Group C by the log-rank test). The analysis of the cytokine kinetics revealed a prominent increase in the level of interleukin-6 in the effusion in Group C. These results suggest that i.c. immunochemotherapy with OK-432 and ACAs may be more beneficial than i.c. chemotherapy alone or immunotherapy alone.

Cytokine-mediated antitumor effect of OK-432 on urinary bladder tumor cells in vitro

Fatal complications from the intravesical instillation of bacillus Calmette-Guérin (BCG) for the treatment of superficial urinary bladder tumors have been reported. OK-432, an immunomodulating agent like BCG, may be an effective and safe agent for the treatment of urinary bladder tumors. We investigated the cytokine-mediated antitumor effect of OK-432 on established human bladder cancer cell lines (T24 and KK-47) in vitro. Peripheral blood mononuclear cells (PBMCs) from a healthy volunteer were cultured with OK-432 for various periods, and the culture supernatants were used as conditioned media. Cytokines in the culture supernatants were quantified. The antitumor effect of OK-432 was evaluated by colony-forming assays, using the conditioned media as the culture media. The colony survival of T24 and KK-47 cells was significantly inhibited by conditioned media from 24-h cultures of PBMCs incubated with OK-432 at concentrations of 0.05 and 0.1 Klinische Einheit (KE)/ml. Conditioned media from PBMCs cultivated with OK-432 for 7 days at 0.01 and 0.05 KE/ml also significantly inhibited the colony survival of both cell lines. Higher concentrations of interleukin-1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF alpha) were detected in conditioned media cultivated with OK-432 for 24 h than in media from PBMCs alone. However, higher concentrations of interferon gamma (IFN gamma) were detected in conditioned media cultivated with OK-432 for 7 days. Approximately 90% of the inhibition of KK-47 cells by the 24-h conditioned media was neutralized by an anti-TNF monoclonal antibody. The inhibition of T24 cells was neutralized approximately 50% by the same antibody. The inhibition of T24 and KK-47 cells by 7-day conditioned media was completely neutralized by an anti-IFN gamma monoclonal antibody. The cultivation of PBMCs with OK-432 inhibited the production of granulocyte-colony-stimulating factor (G-CSF) by PBMCs. The inhibition may play a role in the mechanism of the antitumor effect of OK-432. Urinary bladder tumor cell lines have different sensitivities to cytokines. The cytokines induced by OK-432 vary with the concentration of OK-432 and the culture period. It is suggested that in intravesical instillation of OK-432 for treatment of urinary bladder tumor, the optimal dose and interval of instillation should be considered.

Anticancer chemosensitivity changes between the original and recurrent tumors after successful chemotherapy selected according to the sensitivity assay

OBJECTIVE

The authors compare and characterize the changes in chemosensitivity between the original tumors before chemotherapy and recurrent tumors after responses.

SUMMARY BACKGROUND DATA

The drug resistance in clinical chemotherapy appears to be different from that in experimental chemotherapy, and the profile and mechanisms of clinical drug resistance in recurrent tumors, especially after successful chemotherapy has scarcely been studied.

METHODS

Applied chemotherapies were selected out of four agents, cisplatin (CDDP), adriamycin (ADR), mitomycin-C (MMC) and 5-fluorouracil (5-FU), singly or in combinations by a DNA synthesis inhibition assay, by which the sensitivity of recurrent tumors was assessed. Responses were defined according to the standard criteria, and successful chemotherapy indicates complete response (CR) or partial response (PR) for solid tumors and complete disappearance for malignant effusion.

RESULTS

In 37 patients, the effectiveness of four agents were compared between before chemotherapy and after recurrence, and the response lasted between 2 and 26 months (mean +/- SD, 7.7 +/- 5.5). The results suggest that locally recurred tumors may become resistant to the agents previously administered; by contrast, distantly recurred tumors may not necessarily become resistant to the agents administered. The recurrent tumors are suggested to be sensitive to the agents as follows: locally recurrent solid tumors, 5-FU; distantly recurrent solid tumors, 5-FU and CDDP; locally recurrent effusion, CDDP; distantly recurrent effusion, ADR. Twenty-three of 37 recurrent tumors were re-treated with chemotherapies selected according to the sensitivity assay, singly or in combination with a biologic response modifier (BRM)--a streptococcal preparation, OK-432, or interferon-alpha. Responses were seen in 1 of 13 solid recurrent tumors and in 6 of 10 recurrent effusions. Responses were seen only when the patients were treated with a combination of chemotherapy and BRM.

CONCLUSION

There may be a notable differences in the basic biologic characteristics of tumor cells with respect to local versus distant recurrences, and between effusion versus solid recurrences. Various approaches, including a combination of chemotherapy and BRM, therefore, may have to be applied to overcome these drug resistances in practical chemotherapies for recurrent tumors.

Randomised study of immunotherapy with OK-432 in uterine cervical carcinoma

OK-432, a streptococcal preparation, was administered to patients with stage Ib and II cervical carcinoma except for adeno- and adenosquamous carcinomas. To evaluate the efficacy of OK-432 precisely, 177 patients were stratified by clinical stage, radiotherapy, and lymph node metastasis after complete radical hysterectomy and pelvic lymphadenectomy. Within each stratum, patients were divided randomly into OK-432 and control groups. 85 patients received OK-432 and 92 patients did not. No significant difference was observed in overall 5-year disease free rates between the OK-432 and the control groups, although the mean diameter of erythema on SU-polysaccharide (SU-PS) skin test was larger in the OK-432 group than in the control group. In stage IIb, a significant difference was observed between the OK-432 and control groups. This difference, however, could be attributed in part to the different incidence of the lymph node metastasis. In stage II without lymph node metastasis, 5-year disease free rate was significantly higher in the OK-432 group.

A comprehensive multi-institutional study on postoperative adjuvant immunotherapy with oral streptococcal preparation OK-432 for patients after gastric cancer surgery. Kyoto Research Group for Digestive Organ Surgery

The current study was designed to compare the effects of oral administration of the streptococcal preparation, OK-432, as an adjuvant immunotherapy versus those of intradermal administration of OK-432 on the survival of patients after surgery for gastric cancer. The patients were stratified into two groups after surgery: a curative surgery stratum and a palliative surgery stratum. Then the patients in each stratum were randomly assigned into three groups: an oral placebo group, an oral OK-432 group, and an intradermal OK-432 group. All of the patients were given fluoropyrimidines orally in combination with OK-432 or placebo for 2 years after surgery. A total of 1011 patients were registered between 1982 and 1985, and 970 patients were eligible for statistical analysis. The survival rate of the oral OK-432 group was significantly higher than those of the other two groups after curative surgery. There were no significant difference in the survival rates between the three groups after palliative surgery, however. The effect of oral OK-432 was quite pronounced in patients after curative surgery for stage II to IV gastric cancer, especially in those patients with regional node involvement. Furthermore, it was found that the spleen is necessary for effective immunotherapy with oral OK-432, because the survival rate of the oral OK-432 group was significantly improved in patients whose spleens were preserved, when compared with splenectomized patients. These results demonstrate that oral adjuvant immunotherapy with OK-432 is beneficial after curative surgery for gastric cancer.

The streptococcal preparation OK-432 specifically augments the susceptibility of human urinary bladder tumor cells to autologous peripheral blood lymphocytes

The streptococcal preparation OK-432 was tested for its ability to enhance the susceptibility of fresh urinary bladder tumor (UBT) cells to autologous peripheral blood lymphocytes (PBL) in patients with UBT. PBL treated with OK-432 at 0.1 Klinishe Einheit (KE)/ml for 18 hours killed the human T24-lined UBT cells and freshly separated autologous UBT cells more efficiently than untreated PBL. Treatment of K562 erythroleukemia cells with OK-432 at 0.1 KE/ml for 18 hours had no effect on their susceptibility to lysis by fresh PBL. In contrast, treatment of T24 and fresh autologous UBT cells with OK-432 resulted in an enhancement of their susceptibility to PBL. The susceptibility of autologous UBT cells to both large granular lymphocytes (LGL) and T-lymphocytes was also enhanced by treatment of tumor cells with OK-432. Binding of PBL to T24 and fresh autologous UBT cells was also augmented by treatment of the tumor cells with OK-432. The frequency of binding of OK-432 to fresh UBT cells was positively correlated with the increased target sensitivity to autologous PBL. The inhibition of RNA synthesis in fresh UBT cells by OK-432 was also associated with the elevated susceptibility to autologous PBL. These results indicate that OK-432 activates the autologous tumor killing system through stimulation of effector cells and elevation of target susceptibility to effector cells in patients with UBT, and suggest that the OK-432-augmented target sensitivity to PBL may be oriented specifically to UBT cells and local immunotherapy with OK-432 may be remarkably beneficial in the treatment of UBT.

Use of fibrinogen to enhance the antitumor effect of OK-432. A new approach to immunotherapy for colorectal carcinoma

OK-432 (5 KE), an immunomodulatory agent prepared from an attenuated strain of Streptococcus pyogenes, was dissolved in 1 ml of aprotinin (1000 KIE) and mixed with 80 mg of fibrinogen containing Factor XIII. A single intratumoral injection of the mixture was performed preoperatively under endoscopy in 20 patients with colorectal carcinoma. Postoperative histopathologic examinations revealed the formation of fibrin fibers at the site of injection and marked infiltration of inflammatory cells into the tumor stroma on the day after injection; the formation of granulomas containing many giant cells after 4 to 7 days; and extensive regression of tumor tissue after 14 days. This study suggests that the high concentration of exogenous fibrinogen gelatinized enough to trap OK-432 in tumor stroma and that OK-432 induced granulomatous hypersensitivity to degenerate tumor stroma, thereby causing regression of the tumors.

Effects of bacillus Calmette-Guerin on cytotoxic activities of peripheral blood lymphocytes against human T24 lined and freshly isolated autologous urinary bladder transitional carcinoma cells in patients with urinary bladder cancer

The effects of bacillus Calmette-Guerin (BCG) on the cytotoxic activities of peripheral blood lymphocytes against human T24 lined and freshly separated autologous urinary bladder transitional carcinoma cells in patients with urinary bladder cancer were analyzed in a 12-hour chromium 51 (51Cr) release assay. The results of this study indicate that BCG activates the tumor killing system through stimulation of effector cells and elevation of target cell susceptibility in patients with urinary bladder cancer, suggesting that BCG-augmented cytotoxicity may be oriented specifically to urinary bladder cancer cells. This could explain the remarkable clinical benefits of intravesical instillation of BCG against urinary bladder cancer.

Antitumor action of an acidic glycoprotein (SAGP) from Streptococcus pyogenes in mice

We have shown that an acidic glycoprotein (SAGP) isolated from a cell-free extract of Streptococcus pyogenes (Su strain) prolonged the life-span of Ehrlich ascites carcinoma (EAC)-bearing mice. The present study shows that the life-span prolonging effect of SAGP in EAC-bearing mice was reduced by whole body X-irradiation before EAC inoculation. SAGP (500 micrograms protein/mouse/day X 4, i.p.) also showed a life-span prolonging effect (T/C (%) = 169) on Meth A fibrosarcoma (Meth A)-bearing mice, but the effect of SAGP was abrogated by an i.p. pretreatment of the host with carrageenan, an antimacrophage agent. The spleen cells from the Meth A-inoculated and SAGP-treated mice were found to have a considerable cytostatic activity by a 3H-thymidine incorporation assay. But the activity disappeared in the presence of carrageenan. These results suggest that the in vivo antitumor effects of SAGP are mediated through its immunomodulating action.

In vivo effects of human recombinant tumor necrosis factor alone and in combination with other biological response modifiers on human digestive organ cancer xenografts transplanted in nude mice

The present study was designed to evaluate the effect of rTNF alone or in combination with other BRMs on human digestive organ cancers. Six kinds of human digestive organ cancer xenografts (esophageal, stomach, colonic, pancreatic, bile duct, and liver cancers: EC-YO, GC-YN, CC-KK, PC-HN, BDC-SN and Li-7, respectively) were transplanted in nude mice, and rTNF was administered at 10(3), 5 x 10(3), or 10(4)U/head directly into the tumor 3 times a week for 2 weeks. EC-YO was the most sensitive to rTNF, and intratumoral administration of rTNF at 10(3) U/head caused tumor regression. PC-HN, CC-KK and GC-YN were relatively sensitive to rTNF, and their growth was significantly inhibited by rTNF at 5 x 10(3) U/head, however, the tumors regrew after treatment. Li-7 and BDC-SN were resistant to rTNF. The effects of rTNF in combination with recombinant interferon-gamma (rIFN-gamma), recombinant interleukin-2 (rIL-2), or streptococcal preparation OK-432 were assessed in mice transplanted with GC-YN. All combinations of rTNF at 5 x 10(3) U/head and other BRMs were more effective than rTNF alone, and GC-YN tumors were completely regressed after treatment with a combination of rTNF and rIFN-gamma or rTNF and OK-432. However in all cases, the combination of rTNF at 10(3) U/head and any other BRM did not improve the effect. Furthermore, the adverse effects of the combinations were more serious than those of rTNF alone. TNF may still be a useful cytokine, because it can induce the regression of tumors. However, for its clinical application, a method should be developed to reduce its side effects.

ImuVert activation of natural killer cytotoxicity and interferon gamma production via CD16 triggering

The effect and mechanism of action of ImuVert, a new biological response modifier consisting of ribosomes and natural membrane vesicles of Serratia marcescens, on endogenous natural killer (NK) cells and activated NK activity has been analyzed. The studies showed that endogenous NK activity of peripheral blood mononuclear cells (PBMC) from normal cell donors was significantly increased (P less than 0.03) against K562, U937, and Molt-4 target cells. PBMC from cord blood of newborn infants lacking NK activity were upregulated (1.5-4 fold over endogenous NK activity) by ImuVert. Other studies showed that the abnormal NK activity of PBMC from patients with the human immunodeficiency virus (HIV) infection was significantly augmented in vitro (P less than 0.01) by ImuVert. ImuVert strongly stimulated interferon gamma production and in combination with interleukin 2 produced synergistically enhanced interferon gamma production and greater cytotoxicity than that induced by either alone. Studies on lymphocyte differentiation antigen expression following treatment with ImuVert indicated that ImuVert triggers interferon gamma production through binding the low affinity IgG Fc receptor, type III, CD16. The studies suggest that ImuVert may trigger interferon gamma production by binding to the Fc receptor and that the amplitude of the ensuing reaction and the ability of ImuVert to induce cytotoxicity in a setting where this activity has been down regulated is based on the absence of suppressor activation or direct contra suppressor activity.