Effects of intradermal administration of streptococcal preparation OK-432 on interferon and natural killer cell activities in patients with oral cancer

The Soluble Factor from Oral Cancer Cell Lines Inhibits Interferon-γ Production by OK-432 via the CD40/CD40 Ligand Pathway

(1) Background: OK-432 is a penicillin-killed, lyophilized formulation of a low-toxicity strain (Su) of Streptococcus pyogenes (Group A). It is a potent immunotherapy agent for several types of cancer, including oral cancer. We previously showed that (i) OK-432 treatment induces a high amount of IFN-? production from peripheral blood mononuclear cells (PBMCs), and (ii) conditioned medium (CM) from oral cancer cells suppresses both the IFN-? production and cytotoxic activity of PBMCs driven by OK-432. The aim of this study was to determine the inhibitory mechanism of OK-432-induced IFN-? production from PBMCs by CM. (2) Methods: We performed cDNA microarray analysis, quantitative RT-PCR, and ELISA to reveal the inhibitory mechanism of CM. (3) Results: We found that CD40 plays a key role in IFN-? production via IL-12 production. Although OK-432 treatment upregulated the expression levels of the IL-12p40, p35, and CD40 genes, CM from oral cancer cells downregulate these genes. The amount of IFN-? production by OK-432 treatment was decreased by an anti-CD40 neutralizing antibody. (4) Conclusions: Our study suggests that uncertain soluble factor(s) produced from oral cancer cells may inhibit IFN-? production from PBMCs via suppressing the CD40/CD40L-IL-12 axis.

Cured giant hepatocellular carcinoma after transarterial embolization complicated with liver abscess formation

Many patients with hepatocellular carcinoma cannot be treated surgically because of the advanced stage of the tumor and/or coexisting cirrhosis. Transcatheter arterial embolization (TAE) represents an alternative therapeutic approach for some of these patients. However, it is not a curative measure, and an additional therapy is required to eradicate the residual disease. In this communication, we report a case of 55-year-old man with giant hepatocellular carcinoma located in the right lobe of the liver that was successfully treated with TAE. TAE completely devascularized the tumor in one session. Despite of postembolization antibiotic therapy, complete tumor necrosis led to abscess formation. After 57 days of abscess drainage, necrotic tumor tissue was completely evacuated from the drained cavity; no viable tumor tissue was identified by computed tomography/magnetic resonance imaging scan on a 5 year follow-up. TAE procedure can be suggested as a modulator of antitumor immune response, by exposing tumor antigens after necrosis leading to inflammation. In addition to necrosis caused by TAE, an antimicrobial acute inflammatory reaction in the treated area led to the complete destruction of the giant tumor.

Interferon-α-inducible Dendritic Cells Matured with OK-432 Exhibit TRAIL and Fas Ligand Pathway-mediated Killer Activity

Active human dendritic cells (DCs), which efficiently induce immune responses through their functions as antigen-presenting cells, exhibit direct anti-tumour killing activity in response to some pathogens and cytokines. These antigen-presenting and tumour killing abilities may provide a breakthrough in cancer immunotherapy. However, the mechanisms underlying this killer DC activity have not been fully proven, despite the establishment of interferon-α (IFN-α)-generated killer DCs (IFN-DCs). Here mature IFN-DCs (mIFN-DCs), generated from IFN-DCs primed with OK-432 (streptococcal preparation), exhibited elevated expression of CD86 and human leukocyte antigen-DR (minimum criteria for DC vaccine clinical trials) as well as antigen-presenting abilities comparable with those of mature IL-4-DCs (mIL-4-DCs). Interestingly, the killing activity of mIFN-DCs, which correlated with the expression of CD56 (natural killer cell marker) and was activated via the tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and Fas ligand pathway, was stronger than that of IFN-DCs and remarkably stronger than that of mIL-4-DCs. Therefore, mIFN-DCs exhibit great potential as an anti-cancer vaccine that would promote both acquired immunity and direct tumour killing.

Effect of soluble factors derived from oral cancer cells on the production of interferon-γ from peripheral blood mononuclear cells following stimulation with OK-432

The streptococcal antitumor agent OK-432 is commonly used as an immunopotentiator for immunotherapy in various types of malignant tumors including oral cancer. It has been demonstrated that OK-432 elicits an antitumor effect by stimulating immunocompetent cells, thereby inducing multiple cytokines including interferon (IFN)-γ, interleukin (IL)-2 and IL-12. Serum concentrations of IFN-γ in patients with oral cancer were examined 24 h after administration of OK-432. Serum concentrations of IFN-γ in patients with advanced cancer were significantly lower than those in patients with early cancer. These results suggested that some soluble factors produced by cancer cells may inhibit IFN-γ production with OK-432. Thus, in the present study, an in vitro simulation model was established for the immune status of patients with oral cancer by adding conditioned medium (CM) derived from oral cancer cell lines into a culture of peripheral blood mononuclear cells (PBMCs) derived from a healthy volunteer. We investigated whether soluble factors derived from oral cancer cells affected IFN-γ production from PBMCs following stimulation with OK-432. PBMCs stimulated with OK-432 produced a large amount of IFN-γ; however, both IFN-γ production and cytotoxic activity from PBMCs induced by OK-432 were inhibited by the addition of CM in a dose-dependent manner. In order to examine these inhibitory effects against IFN-γ production, the contribution of inhibitory cytokines such as IL-4, IL-6, IL-10, transforming growth factor-β and vascular endothelial growth factor was investigated. However, neutralization of these inhibitory cytokines did not recover IFN-γ production inhibited by CM. These results indicated that unknown molecules may inhibit IFN-γ production from PBMCs following stimulation with OK-432.

Growth inhibition and apoptosis by an active component of OK-432, a streptococcal agent, via Toll-like receptor 4 in human head and neck cancer cell lines

Toll-like receptor 4 (TLR4) plays a significant role in cancer therapy as receptors of bacteria-derived immunotherapeutic agents such as OK-432, a streptococcal immunotherapeutic agent. In addition, recent reports demonstrated that TLRs, including TLR4, are also expressed in cancer cells as well as in immunocompetent cells. It is a problem in cancer therapy that the immunoadjuvant may activate survival signals such as nuclear factor (NF)-κB or mitogen-activated protein kinases (MAPKs) in cancer cells via TLRs. In the current study, we investigated responsiveness of human head and neck cancer cell lines against TLR4 ligands, OK-PSA, an active component of OK-432, and a lipopolysaccharide (LPS). Stimulation with LPS or OK-PSA resulted in the activation of NF-κB in these cell lines expressing TLR4 and MD-2 that is a significant coreceptor for TLR4 signaling. Interestingly, OK-PSA induced cell-growth inhibition, while LPS enhanced the proliferation of the cancer cells. OK-PSA induced NF-κB activation more slowly than that induced by LPS. In addition, phosphorylation of p38 MAPK by OK-PSA was only slight compared with that by LPS. OK-PSA also induced apoptosis of the cancer cells mediated by the activation of caspase 1, 3 and 8 in a p53-independent manner. These findings strongly suggest that active components of OK-432 may elicit anti-cancer effects via enhancing host immunity as well as via directly inducing the growth inhibition and apoptosis of head and neck cancer cells through TLR4 signal.

Enhancement of antitumor activity of OK-432 (picibanil) by Triton X-114 phase partitioning

OK-432 (Picibanil), a Streptococcal immunotherapeutic agent, has been used for immunotherapy of various cancers as a biological response modifier (BRM). However, OK-432 contains multiple components consisting of immunotherapeutic ones and contaminants which may weaken the effects or exert side-effects. In this study, we investigated extraction of contaminants from OK-432 using Triton X-114 (TX-114)-water phase partitioning and examined an antitumor effect of the resulting preparation. OK-432 was subjected to TX-114 partitioning to give residual precipitate designated as OK-TX-ppt. OK-TX-ppt exerted no TLR2-mediated activity, but induced interleukin (IL)-6 in human PBMC. OK-TX-ppt also induced tumor necrosis factor (TNF)-alpha, IL-10, IL-12, and interferon (IFN)-gamma in PBMC. Moreover, IFN-gamma-inducing activity of OK-TX-ppt was significantly higher and IL-10 production was lower than that of OK-432. In tumor-bearing mice model, administration of OK-TX-ppt i.p. extended the survival time of Meth-A-bearing mice compared to OK-432. OK-TX-ppt also increased the levels of IL-12 and IFN-gamma in mouse spleen cells in vitro. These results indicated that TX-114 partitioning removed some contaminants, which attenuates the antitumor effect, from OK-432 and increase the immunotherapeutic effects of OK-432.

Generation of a monoclonal antibody agonist to toll-like receptor 4

Toll-Like Receptor 4 (TLR4) has recently been identified as the lipopolysaccharide (LPS) receptor. Upon stimulation of TLR4 with LPS, a Th1 type cytokine response is observed. This immune modulation is thought to have a potential benefit in anti-tumor therapy. We have generated a TLR4 antibody agonist (5D24.D4) that mimics the action of the natural ligand. 5D24.D4 and LPS stimulation of TLR4 leads to a similar response, including IL-8 secretion, activation of NF-kB-mediated transcription, and the induced expression of an overlapping set of target genes. 5D24.D4 may be beneficial as an adjuvant anti-tumor therapy.

Cell-mediated immunity and head and neck cancer: with special emphasis on betel quid chewing habit

Betel quid (BQ) chewing is popular in Taiwan, India, and many southeast-Asian countries. BQ chewing has strong association with the risk of oral leukoplakia (OL), oral submucous fibrosis (OSF), and oral cancer (OC). BQ components exhibit genotoxicity and may alter the structure of DNA, proteins and lipids, resulting in production of antigenicity. BQ ingredients are also shown to induce keratinocyte inflammation by stimulating the production of prostaglandins, TNF-alpha, IL-6, IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF) in keratinocytes. These events may provoke tissue inflammation, early cell-mediated immunity (CMI), and immune surveillance in BQ chewers. However, BQ components also directly affect the functional activities of immunocompotent cells, and moreover tumor cells may hypo-respond to the CMI via diverse mechanisms such as induction of apoptosis of lymphocytes, induction of production of suppressor T cells, downregulation of MHC molecules in tumor cells, etc. Clinically, an alteration in lymphocyte subsets, a decrease in total number of lymphocytes, and a reduction in functional activities of CMI have been observed in isolated peripheral blood mononuclear cells (PBMC) and tumor infiltrated lymphocytes (TIL) in patients with OSF, OL or OC. Adaptation of tumor cells to immune system may promote clonal selection of resistant tumor cells, leading to immune tolerance. Future studies on effects of BQ components on CMI and humoral immunity in vitro and in vivo can be helpful for chemoprevention of BQ-related oral mucosal diseases. To elucidate how virus infection, tobacco, alcohol and BQ consumption, and other environmental exposure affect the immune status of patients with oral premalignant lesions or OC will help us to understand the immunopathogenesis of OC and to develop immunotherapeutic strategies for OC.

Anti-tumor immune response induced by the fractions derived from OK-432, a streptococcal preparation, by using a monoclonal antibody TS-2 that neutralizes the interferon-gamma-inducing activity of OK-432: comparison between the TS-2-binding and TS-2-unbinding fraction

We have previously isolated a lipoteichoic acid (LTA)-related molecule (OK-PSA) from OK-432, a streptococcal agent, by affinity chromatography on a CNBr-activated Sepharose 4B bound TS-2 monoclonal antibody (mAb) that neutralizes the interferon (IFN)-gamma-inducing activity of OK-432. In the current study, we compared the cytokine-inducing and anti-tumor activities of OK-PSA, a TS-2-binding fraction, with those of OK-PTF, a TS-2-unbinding fraction, in order to determine the efficacy of OK-PSA for clinical use in affinity chromatography using TS-2. In the in vitro experiments using human peripheral blood mononuclear cells (PBMCs), OK-PSA markedly induced Th1-type cytokines, while interleukin (IL)-6 and IL-10, Th2-type cytokines, were induced by OK-PTF. Th1-cytokine induction by OK-PTF was not dose-dependent and was suppressed when PBMCs were treated with a high concentration of OK-PTF. In a mouse model, Th1 cytokines were also induced by OK-PSA and Th2 cytokines were induced by OK-PTF. Th2 cytokine-inducing activity of OK-PTF was accelerated in tumor-bearing mice relative to that in healthy mice. Although the anti-tumor effect of OK-PTF was statistically significant, it was much weaker than that of OK-PSA. A significant difference between the anti-tumor effect of OK-PSA and that of OK-PTF was observed (P<0.05). Finally, OK-PSA elicited its cytokine-inducing effect via Toll-like receptor (TLR) 4, whereas OK-PTF-induced signaling was mediated by both TLR2 and TLR4. These findings strongly suggested that the affinity chromatography using TS-2 is a useful strategy to separate the effective component for cancer therapy (OK-PSA) from other components.

Involvement of Toll-like receptor 4 signaling in interferon-gamma production and antitumor effect by streptococcal agent OK-432

BACKGROUND

The streptococcal agent OK-432 has been used for immunotherapy of head and neck cancer, among other malignancies, but its mechanism of action is unknown. Because the Toll-like receptor 4 (TLR4)/MD-2 complex is important in enabling the mammalian immune system to recognize bacterial components, we investigated whether expression of the TLR4 and MD-2 genes is associated with OK-432-induced anticancer immunity.

METHODS

Peripheral blood mononuclear cells (PBMCs) from 28 patients with head and neck cancer were analyzed for TLR4 and MD-2 mRNA expression by reverse transcription-polymerase chain reaction (RT-PCR) analysis. PBMCs were treated in vitro with OK-432 or with OK-PSA (a lipoteichoic-acid-related molecule that is an active component of OK-432), and interferon-gamma (IFN-gamma) mRNA expression, an immune response measure, was analyzed by RT-PCR. Patient sera collected 24 hours after OK-432 administration were examined for IFN-gamma protein using an enzyme-linked immunosorbent assay. Lewis lung carcinoma-bearing wild-type C57BL/6 and TLR4-deficient mice (four mice per group) received intraperitoneal injections of OK-432, and tumor volumes and sera IFN-gamma levels were measured over time. All statistical tests were two-sided.

RESULTS

Twenty patients expressed both TLR4 and MD-2. Expression of TLR4 and MD-2 genes was associated with the in vivo IFN-gamma induction in 19 patients administered OK-432 (Fisher's exact test P<.001). Although both OK-432 and OK-PSA induced IFN-gamma expression from PBMCs in vitro, expression of TLR4 and MD-2 was associated only with IFN-gamma expression induced by OK-PSA (P<.001). In vivo intraperitoneal administration of OK-432 resulted in an increase of IFN-gamma in sera from wild-type mice but not in sera from TLR4-deficient mice. Tumors in wild-type mice treated with OK-432 were statistically significantly smaller than those in mice treated with saline (P =.007). By contrast, in TLR4-deficient mice, there was no difference in tumor volume between the two treatment groups.

CONCLUSIONS

TLR4 and MD-2 may mediate OK-432-induced anticancer immunity.

Protective effect of OK-432 on mice against endotoxemia and infection with Pseudomonas aeruginosa and Salmonella enteritidis

OK-432 has been used clinically as a biological response modifier for cancer therapy. We investigated here the protective effects of OK-432 against endotoxic shock and infectious death caused by Pseudomonas aeruginosa and Salmonella enteritidis in mice and proposed a possible mechanism. Pretreatment of OK-432 reduced the lethality of lipopolysaccharide (LPS)-induced endotoxic shock in D-(+)-galactosamine-sensitized C3H/HeN mice. OK-432 did not affect the TNFalpha production in blood, but it did decrease the susceptibility to TNFalpha. Furthermore, an acceleration of LPS clearance from blood was detected. The pretreatment of OK-432 also decreased the lethality of mice in bacterial infection caused by P. aeruginosa and S. enteritidis. The rapid decrease of the viable bacteria from the circulating blood and in spleen and liver in mice was observed in a manner similar to LPS clearance. These findings indicate that the protective effect of OK-432 against the endotoxemia and bacteremia may depend on an up-regulation of clearance of LPS and bacteria and the augmented resistance to TNFalpha.

Induction of cytokines and killer cell activities by cisplatin and 5-fluorouracil in head and neck cancer patients

It has been suggested that certain antitumor agents stimulate antitumor immunity. In the present study, we examined whether cisplatin and 5-fluorouracil (5-FU) accelerate the antitumor host responses in head and neck cancer patients. Two groups of patients were studied, i.e. an untreated (UT) group and a treated, disease-free (TDF) group that received chemo-immunotherapy in combination with radiotherapy and operation. When peripheral blood mononuclear cells (PBMC) derived from head and neck cancer patients were treated with cisplatin or with 5-FU, interferon-gamma, tumor necrosis factor (TNF)-alpha, TNF-beta, interleukin (IL)-1beta, IL-6, IL-12 and IL-18 as well as killer cell activities were significantly induced in both groups. In this case, these activities induced by cisplatin in UT showed lower levels than those in TDF, whereas the activities induced by 5-FU in the UT group demonstrated almost similar levels to those in TDF. These activities were significantly inhibited by anti-asialo-GM1 antibody. Furthermore, cytokine levels in sera and killer activities of PBMC derived from the cancer patients were significantly increased after cisplatin administration. These findings suggest that cisplatin and 5-FU increase anticancer immunity mediated by induction of cytokines and killer cell activities in patients with head and neck cancer.

OK-432 and 5-fluorouracil, doxorubicin, and mitomycin C (FAM-P) versus FAM chemotherapy in patients with curatively resected gastric carcinoma: a randomized Phase III trial

BACKGROUND

The streptococcal agent OK-432 is used widely as a potent biologic response modifier. Accumulated evidence suggests that OK-432 exerts antineoplastic effects by a direct cytotoxic or inhibitory effect on tumor cells. The clinical efficacy of OK-432 has been reported for various tumors. In this randomized Phase III study, the authors compared 5-fluorouracil (5-FU), doxorubicin, mitomycin C, and the intradermal administration of OK-432 (FAM-P) with the standard FAM regimen in patients with gastric carcinoma who underwent curative resection.

METHODS

From May 1988 until November 1991, a total of 99 patients were entered into this randomized trial. The patients were stratified according to the American Joint Committee on Cancer stage of disease (i.e., Stage IB, II, and III). Fifty patients were treated with the FAM regimen here and throughout text.: 5-FU, 750 mg intravenously (i.v.), on Days 1, 8, 29, and 36; doxorubicin, 30 mg/m2 i.v., on Days 1 and 29; and mitomycin C, 10 mg/m2 i.v., on Day 1. Forty-nine patients received the FAM-P regimen: 5-FU, 750 mg i.v., on Days 1, 8, 29, and 36; doxorubicin, 30 mg/m2 i.v., on Days 1 and 29; mitomycin C, 10 mg/m2 i.v., on Day 1; and OK-432 5.0 Klinishe Einheit (clinical unit) injected intradermally weekly.

RESULTS

The survival difference was statistically significant between the patients receiving the FAM and FAM-P regimens (5-year survival of 52% vs. 62%; P = 0.04). A comparison between disease free survival in FAM and FAM-P patients showed a borderline advantage for the FAM-P group (P = 0.053). When Stage IB, Stage II, and Stage III patients were analyzed separately, the difference in survival between two regimens was significant in Stage III patients (P = 0.049) and the disease free survival was of borderline significance (P = 0.06), but not in patients with Stage IB and II disease. The significant toxicity of OK-432 was mild fever, which was controlled with acetaminophen.

CONCLUSIONS

The results of this study show that OK-432 may be an active, well tolerated agent for the treatment of curatively resected gastric carcinoma. However, these findings should be confirmed by a multicenter randomized study with a large sample size.

Inhibition by streptococcal immunopotentiator OK432 of lymph-node metastasis in hamster cheek-pouch carcinoma with enhancement of tumour necrosis factor-alpha and interleukin-6 in serum

A well-known metastic model of human oral cancer employs 9,10-dimethyl-1,2-benzanthracene (DMBA) to induce hamster cheek-pouch carcinoma. Streptococcal immunopotentiator OK432 was studied here for its inhibitory effect on lymph-node metastasis in that model. The intraperitoneal administration of OK432, after excision of cheek-pouch tumours induced by DMBA, resulted in a marked reduction in the incidence of cervical lymph-node metastasis to 7%, a significant decrease beneath the rates observed for control animals not receiving OK432 (40%). OK432 also caused an increased in serum levels of tumour necrosis factor-alpha and interleukin-6 in tumor-bearing hamsters. These results suggest that the immune response may play an important part in the antimetastatic effects of OK432.

Protection of OK-432, a Streptococcus pyogenes preparation, against lethal infection of mice with herpes simplex virus

We have studied the protective effect of OK-432, a biological response modifier (BRM) of Streptococcus pyogenes origin, on the lethal infection of mice with herpes simplex virus (HSV)-1. A single intraperitoneal (i.p.) injection of more than 10 micrograms of OK-432, when given at least two days before the infection, gave a marked effect yielding nearly 100% protection against ordinarily lethal infection. The protection was independent of the amount of infected virus inoculated. When given after the infection, the agent even at the maximal dose (100 micrograms), produced only a marginal effect. A single i.p. administration of OK-432 augmented the natural killer (NK) activity of peritoneal exudate cells and spleen mononuclear cells in mice 2 to 3 days after injection of OK-432, coinciding with the times when it induced a survival effect on HSV-infection. Treating OK-432-treated mice with a combination of an anti-macrophage agent, silica, and an anti-NK cell agent, anti-asialo GM1 serum, before infection diminished the antiviral effect of OK-432. The OK-432 protection against HSV infection was also markedly diminished in athymic nude mice. Thus, the protective effect of OK-432 on lethal HSV infection seems to be based on the activation of NK cells, macrophages, and T lymphocytes.