Role of interleukin-2 and interferon-gamma in induction of activated natural killer cells from mice primed in vivo and subsequently challenged in vitro with the streptococcal preparation OK432

miR-144-3p exerts anti-tumor effects in glioblastoma by targeting c-Met

The study aimed to explore the specific function and mechanism of miR-144-3p in glioblastoma (GBM) cells with different phosphatase and tensin homolog (PTEN) phenotypes. We demonstrated that the miR-144-3p level was significantly down-regulated in glioma compared with the non-neoplastic brain tissues, and decreased with ascending grades. The loss of miR-144-3p effectively predicted the decreased overall survival in glioma patients. Interestingly, the expression of MET was up-regulated and inversely associated with miR-144-3p level in glioma tissues. Next, we certified that miR-144-3p specifically bound to MET 3'-untranslated region (3' UTR) and inhibited its expression. miR-144-3p potently repressed GBM cell proliferation and invasion via suppressing MET in vitro and in vivo. In addition, our results showed no difference in malignancy inhibition induced by miR-144-3p in GBM cells with different PTEN phenotypes. miR-144-3p inhibited several survival signaling pathways by targeting MET independent of PTEN status in GBM cells. Over-expression of miR-144-3p inhibited survival capability and increased apoptosis, resulting in enhancement of radiation and temozolomide sensitivity. Our data provide new insights into the potential application of miR-144-3p in GBM therapy by targeting MET and then inhibiting the downstream signaling.

Antitumor effects of interleukin-2 gene-modified fibroblasts in an orthotopic colon cancer model

We transduced the interleukin-2 (IL-2) gene into murine fibroblasts BALBCL7 or murine colon cancer CT26 using a retroviral vector. BALBCL7 transduced with IL-2 gene secreted 748 pg/ml of IL-2, whereas IL-2 gene-modified CT26 secreted 1,167 pg/ml of IL-2 (48 h incubation, 1x10(6)/ml). Then, we inoculated gene-modified BALBCL7 and/or CT26 cells into BALB/c female mice, and observed the tumor growth. The tumor growth was inhibited in mice inoculated with parental CT26 plus IL-2 gene-modified BALBCL7, compared with that in mice given parental CT26 alone (P<0.01). Moreover, we investigated the cytotoxic activity of spleen cells derived from mice treated with gene-modified cells, and performed phenotypic analysis of the effector cells. The killer cells derived from mice inoculated with IL-2 gene-modified BALBCL7 plus parental CT26 showed higher cytotoxic activity than those from mice inoculated with CT26 alone. The cytotoxic activity was almost completely blocked by anti-CD8 antibody (Ab), and partially blocked by anti-asialo GM1 Ab. Next, we inoculated CT26 tumor tissue into murine cecum orthotopically, and treated the animals with gene-modified BALBCL7 plus parental CT26. The tumor size in the cecum was significantly decreased, compared with parental CT26 alone (P<0.01).

Effects of streptococcal preparation OK-432 on cytokine induction in spleen and tumour tissues of mice bearing MH-134 tumour cells

Streptococcal preparation OK-432 is a bacterial immunopotentiator extensively used in Japan for adjuvant cancer therapy. Using C3H/He mice bearing MH-134 tumour cells, cytokine inductions of tumour necrosis factor-alpha, interleukin 1 beta, interleukin 6 and interferon-gamma were determined in spleen and tumour tissues by reverse transcriptase-polymerase chain reaction analysis. No significant induction of cytokine mRNA was observed after subcutaneous administration of OK-432 (OK-432, s.c.) or after intratumoural injection of IFN-gamma (IFN-gamma, i.t.), compared with controls, either in spleen or tumour tissues. In contrast, subcutaneous administration of OK-432 followed by intratumoural OK-432 injection (OK-432, s.c. + i.t.) was found to induce some cytokine mRNAs significantly. The mRNA levels of tumour necrosis factor alpha and interferon-gamma in spleen tissue and those of interleukin 1 beta and interferon-gamma in tumour tissues were significantly elevated in mice with OK-432, s.c. + i.t. treatment compared with controls. These results suggest that treatment with OK-432, s.c. + i.t. effectively induced splenic antitumour immunity as well as local immunity against tumour cells.

Successful immunochemotherapy for patients with malignant mesothelioma: report of two cases

Malignant mesothelioma is a clinically aggressive tumor and has a poor prognosis; therefore, the selection of therapeutic strategies is important to improve the prognosis. Two patients with intraperitoneal malignant mesothelioma received combination therapy as follows: (1) case-oriented chemotherapy according to the results of a chemosensitivity test, and (2) adoptive immunotherapy using cytotoxic T lymphocytes (CTL). The chemosensitivity test was assessed by an MTT colorimetric assay. CTL was generated by a mixed culture with autologous tumor cells, and activated by immobilized anti-CD3 monoclonal antibody and interleukin-2. The MTT assay indicated that cisplatin and adriamycin were sensitive drugs in both patients, and they thus received the case-oriented chemotherapy according to the MTT assay. The activated CTL exhibited a high cytotoxicity against autologous malignant mesothelioma cells, and were transferred intraperitoneally. The patients were controllable for ascites, and the tumor masses gradually vanished (partial response). Chemoimmunotherapy is thus considered to be an effective treatment for intraperitoneal malignant mesothelioma, especially to improve the quality of life.

Case report: successful palliative treatment with intraperitoneal OK-432 injection for epithelioid haemangioendothelioma presenting with intractable ascites

Epithelioid haemangioendothelioma is an unusual type of endothelium-derived vascular tumour of borderline malignancy, which has high variability in clinical presentations, depending on the primary site of involvement. We report on a 20-year-old woman who presented with progressive abdominal fullness for 6 months. Multiple lung and liver nodules with pleural effusion and profuse ascites were found. The diagnosis of epithelioid haemangioendothelioma was made after wedge biopsy of the liver. The ascites was intractable and refractory to strong diuretic therapy and repeated paracentesis. Therefore, six courses of intraperitoneal injection of OK-432 were administered. The ascites subsided to a minimal amount after treatment and the patient remained symptom-free for approximately 8 months. The ascites recurred later and another three courses of intraperitoneal injection of OK-432 were administered. The ascites disappeared again. The patient has remained symptom-free since the end of the second period of treatment.

Fibronectin promotes the proliferation of cytotoxic T lymphocytes generated from cancer patients

We studied whether fibronectin (FN) enhances the activity of autologous tumour-reactive cytotoxic T lymphocytes (CTLs) generated from cancer patients. The proliferation of CTLs stimulated by immobilised anti-CD3 monoclonal antibody and interleukin 2 (IL-2) was enhanced three or four times by immobilised FN. whereas soluble FN did not alter the DNA synthesis of CTLs. Moreover, the cytotoxic activity of CTLs was augmented by FN stimulation against autologous tumour cells [4 h 51Cr release assay: FN(+) 16.7 +/- 4.7% vs FN (-) 11.8 +/- 3.1%; 16 h 51Cr release assay: FN(+) 24.8 +/- 4.7% vs FN (-) 16.5 +/- 5.7%, P<0.05]. The major cell surface phenotype of CTLs with FN was CD3+, CD4+ and CD25+ in 6 weeks' culture. Cytotoxicity against autologous tumour cells was inhibited by anti-HLA class I monoclonal antibody (MAb). The autologous tumour-killing activity of CTLs was suppressed by the elimination of CD4+ cells. Moreover, the cytokine production of CTLs was augmented by FN stimulation. Especially, the production of IL-2, interferon gamma (IFN-gamma), and granulocyte macrophage colony-stimulating factor (GM-CSF) was significantly augmented by FN stimulation (P<0.05). Thus, CTLs generated by FN might have both killer and helper functions, since they could lyse autologous tumour cells and secrete various cytokines, including IL-2.

Modulation of the No Secretion in the Pichilan-Activated Murine Macrophage Cell Line, Malu

The mechanism of action of pichilan, a (1->3)-β-D-glucan on nitric oxide production by a murine macrophage cell line, MALU cells, was examined. Different metabolic pathways were investigated in order to understand pichilan-induced NO secretion. We demonstrate in the present paper that neither the acid arachidonic metabolism, the cAMP nor Ca2+accumulation occured in the pichilan mechanism of action on NO secretion. On the other hand, we observed that a phorbol ester, PMA, modulated the NO secretion. An inhibition of 36% of the NO secretion was observed; consequently, pichilan could regulate the NO secretion by way of the protein kinase C. Furthermore, we demonstrated that TNF production stimulated by pichilan activation induced NO secretion by MALU cells. TNF would be the main modulator of NO secretion by pichilan or LPS-activated MALU cells. Moreover, we can note that pichilan and LPS did not act similarly on nitrite secretion by MALU cells.

Generation of CD4+ cytotoxic T lymphocytes stimulated by immobilized anti-CD3 monoclonal antibody and interleukin-2 in cancer patients

The proliferation of autologous tumor-reactive cytotoxic T lymphocytes (CTL), induced by autologous mixed lymphocyte tumor-cell culture, was remarkably enhanced by activation with immobilized anti-CD3 monoclonal antibody (MAb) and interleukin-2 (IL-2), as compared with IL-2 alone. The activated CTL exhibited high cytotoxicity against autologous tumor cells. Cytotoxicity against autologous tumor cells was inhibited by anti-HLA-DR MAb. In negative selection with immunomagnetic beads, cytotoxicity against autologous tumor cells was inhibited by the elimination of CD4+ cells. The major cell-surface antigens of the activated CTL were CD3+, CD4+, CD25+, CD45RO+ and CD45RA-, suggesting helper T cells, and the activated CTL produced IL-2. It is concluded that the CTL activated by immobilized anti-CD3 MAb and IL-2 were CD4 cells that had both killer and helper functions. Our findings indicate that adoptive immunotherapy using these activated CTL would be effective in cancer patients.

Enhancement of natural killer cell activity in human immunodeficiency virus-infected subjects by in vitro treatment with biologic response modifier OK-432

A decrease in natural killer (NK) cell function has been related to the progression of human immunodeficiency virus (HIV) infection. In the present study, we assessed the ability of a streptococcus-derived biologic response modifier, OK-432, to augment NK lysis of uninfected K562 and U937 cells and HIV-infected U937 cells by peripheral blood mononuclear cells (PBMC) from HIV-seropositive homosexual men. Optimal two- to fourfold increases in lysis of the three targets were observed after pretreatment of PBMC from HIV-negative subjects for 4 h with 2 micrograms of OK-432 per ml. This effect was related primarily to gamma interferon (IFN-gamma) production induced by OK-432 and was not linked to production of tumor necrosis factors alpha and beta or to monocytes in the cultures. The enhancing effect of OK-432 on NK cell function was diminished but still evident in PBMC from subjects with relatively early-phase (< 3-year) HIV infection and high CD4+ cell counts and was lower in subjects with longer-term HIV infection (> 3 years), in association with reduced production of IFN-gamma. Augmentation of NK cell activity in HIV-infected men by OK-432 was comparable to that induced by treatment of cells with 1,000 U of IFN-alpha or interleukin 2 per ml. The data suggest that the NK cell-enhancing effects of OK-432 are at least in part mediated by IFN-gamma and that OK-432 may be effective in treatment of patients with early-phase HIV infection.

Enhancement of tumor cell susceptibility to lymphokine-activated killer cells by treatment with the streptococcal preparation OK432

We investigated whether tumor cell lysis by LAK cells was augmented by treatment with OK432 in vitro. NK and LAK activity against K562 cells was not enhanced by their treatment with OK432. In contrast, the susceptibility of OK432-treated Daudi and KATO-III cells to lysis by LAK cells was enhanced. Succinate dehydrogenase activity and RNA synthesis were impaired in Daudi and KATO-III cells by treatment with OK432, and moreover the expression of HLA Class I antigen and beta 2-microglobulin was inhibited in OK432-treated KATO-III cells. Thus, it is suggested that the enhancement of the susceptibility of OK432-treated tumor cells with regard to succinate dehydrogenase activity, RNA synthesis, and HLA Class I antigen expression.

Significant antitumor effect of a synthetic lipid A analogue, DT-5461, on murine syngeneic tumor models

The antitumor effect of a synthetic lipid A analogue, DT-5461, was investigated using syngeneic tumor models in mice. Intravenous injection of DT-5461 into mice transplanted with solid tumors of MethA fibrosarcoma, MH134 hepatoma, MM46 mammary carcinoma, Lewis lung carcinoma (3LL), and colon adenocarcinomas 26 and 38 resulted in significant reductions in the weight of all tumors except Colon 26, with marked hemorrhagic necrosis of tumor tissues. Efficacy was almost equal to that of an Escherichia coli-type synthetic lipid A (compound 506), and also to those of some chemotherapeutics including Adriamycin, mitomycin C, fluorouracil and cisplatin. Furthermore, DT-5461 was more effective than other immunotherapeutics, including picibanil (OK-432) and lentinan. However, its antitumor effects were inferior to those of Adriamycin or OK-432 against the malignant ascites caused by intraperitoneal inoculation with MethA or with MH134 cells; life span was not prolonged by either intraperitoneal or intravenous administration. In addition, although DT-5461 showed direct inhibitory effects on the in vitro growth of MethA or MH134, these were much weaker than those of Adriamycin. These findings clearly indicated that DT-5461 with systemic administration is a highly effective antitumor agent on solid tumors, and suggest that the antitumor effect of DT-5461 with potent necrotizing activity might derive from indirect mechanisms related to the activation of host immune systems and not to the weak direct cytotoxicity.

Clinical and immunological evaluation of intraoperative radiation therapy for patients with unresectable pancreatic cancer

The clinical efficacy of intraoperative radiation therapy (IORT) and the changes of immunological parameters were investigated. Nine patients with unresectable pancreatic cancer were treated with IORT (2,500-3,500 cGy) and the changes of various immunological parameters were compared with those in 11 patients with advanced cancer who received external beam irradiation therapy (XRT), 2,500-3,500 cGy. After IORT, 71% of patients obtained pain relief, two of the nine patients showed a partial response, and the serum CA 19-9 level decreased in six patients. However, the median survival was only 210 days. Natural killer activity, lymphokine-activated killer activity, and interferon gamma-activated killer activity were not inhibited by IORT, and phytohemagglutinin-induced blastogenesis was actually augmented after IORT, whereas all these parameters were inhibited by XRT. Thus, it is suggested that IORT may augment or at least stabilize systemic antitumor immunity.

Effect of Salmonella bacteria on the interaction of human NK cells with endothelial cells

Leukocyte-endothelial cell adhesion and its regulation are essential and complex initial aspects of lymphocyte migration. Various factors (IL-1, TNF-alpha, IFN-gamma etc.) have been shown to increase the endothelial adhesiveness for human lymphocytes, including natural killer cells (NK cells). In this work we have demonstrated that pretreatment of either the target endothelial cell monolayers or the binding LGL-cells with mR595 Salmonella Minnesota bacteria results in a substantial increase in the adhesiveness of LGL-cells to endothelial cells. The increase was more prominent when the endothelial cells were treated than when the adhering LGL-cells were similarly pretreated. The adhering cell population was significantly enriched with CD56 (Leu19) and CD16 positive cells, i.e. cells with NK cell phenotype, when the lymphocyte population was pretreated. However, the pretreatment of EC resulted in a non-specific increase in EC adhesiveness since the relative proportion of CD56+ (Leu19), CD16+ and CD3+ cells among the adhering cells did not significantly differ from the starting population. The bidirectional enhancement of adhesiveness of human NK cells to endothelium by mR595 Salmonella bacteria may be significant in the host defense responses against microbial infections.

Augmentation of antimetastatic effect on Lewis lung carcinoma (3LL) in C57BL/6 mice by priming with Lactobacillus casei

The augmentation of the antimetastatic effect of heat-killed cells of Lactobacillus casei YIT9018 (LC9018) on Lewis lung carcinoma (3LL) in C57BL/6 mice by presensitization (priming) with LC9018 was examined. Intralesional injection of LC9018 into 3LL-bearing mice inhibited both the growth of the primary tumors and the formation of lung metastases, and this effect was significantly augmented by subcutaneous injection of LC9018 before the tumor inoculation. In the LC9018-primed mice, intraperitoneal administration of LC9018 into syngeneic hosts after priming induced a high level of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) in the peritoneal cavity. At this time, T cells of the spleen cells from the LC9018-primed mice proliferated and produced IL-2 when co-cultured with LC9018 as antigen in vitro. Also, the phenotype of these T cells was found to be L3T4+ and Ly-2.2- T cells by analysis by flow cytometry. These results suggest that LC9018-reactive helper T (Th) cells were induced by the priming and subsequent challenge with LC9018, and that IL-2 or IFN-gamma, which was produced by the activated LC9018-reactive Th cells, augmented a host immune response resulting the antitumor activity.

Functional and phenotypic analyses of interleukin 2-activated tumor-infiltrating lymphocytes

The tumor-infiltrating lymphocytes (TILs) were cultured with interleukin 2 (IL-2) to induce the activated killer cells possessing autologous tumor-killing activity, and analysed their cell surface phenotypes and assessed anti-tumor killing activity. Furthermore, the activated TILs were transferred into 7 patients adoptively resulting in complete remission in a patient with pancreatic cancer and partial remission in another patient with gastric cancer. The cytotoxic activities of activated TILs at 3 weeks-incubation was 72 +/- 15, 42 +/- 26, 27 +/- 21 and 25 +/- 15% against K562, Daudi, KATO-III and autologous tumor, respectively. The negative selection method, indicated that the killer cells recognizing autologous tumor cells consisted of CD4- or CD8-positive T lymphocytes and CD16- or CD56-positive natural killer cells. The activated TILs could not only lyse cultured tumor cell lines, but also autologous tumor cells.

Successful adoptive immunotherapy with OK432-inducible activated natural killer cells in tumor-bearing mice

We had demonstrated that the NK cell mediated cytotoxicity of murine spleen cells could be augmented by in vivo priming and subsequent in vitro challenge with a streptococcal preparation OK432, and the cell surface phenotype of induced killer cells was Thy-1+, asialo GM1+, suggesting that the activated cells were of NK lineage (OK-NK cell). We had also clarified that IL-2 played a major role in inducing the OK-NK cells via the production of IFN-gamma. In this study, we examined the effect of adoptive transfer of OK-NK cells on syngeneic tumors in mice. Mice were implanted with SP2 myeloma cells intraperitoneally (i.p.), or C26 colon adenocarcinoma cells subcutaneously to make the models of peritonitis carcinomatosa or solid tumor, and the OK-NK cells were transferred i.p. or intratumorally, adoptively. By the adoptive transfer of OK-NK cells, 92% of mice bearing SP2-tumor had be cured. The tumor growth of C26-solid tumor was inhibited, and the survival rate of mice bearing C26-tumor was significantly increased. The intratumoral remnants of 125I-labelled OK-NK cells were 61, 27 and 8% at 4, 12 and 36h after intratumoral transfer, respectively. By multiple transfer of OK-NK cells, the antitumor effect was more effectively augmented than that of a single transfer. Results in this study suggested that OK-NK cells could be useful for the therapy of cancer patients.