Chemo-Immunotherapy with Oxaliplatin and Interleukin-7 Inhibits Colon Cancer Metastasis in Mice

Combination of immunotherapy and chemotherapy has shown promise for cancer. Interleukin-7 (IL-7) can potentially enhance immune responses against tumor, while oxaliplatin (OXP), a platinum-based drug, can promote a favorable immune microenvironment and stimulate anticancer immune responses. We evaluated the anti-tumor activity of IL-7 combining OXP against a murine colon carcinoma in vitro and in vivo and studied the tumor immune microenvironment to investigate whether the combined treatment affects on the local immune cell populations. Utilizing lung and abdomen metastasis models by inoculation of CT26 mice colon cancer cells, we evaluated the anti-tumor efficacy of combining IL-7 and OXP in mice models. Tumor immune microenvironment was evaluated by flow cytometric analysis and immunohistochemical staining. Our study showed that the in vivo administration of IL-7 combined with OXP markedly inhibited the growth of tumors in lung and abdomen metastasis models of colon cancer. IL-7 alone had no effect on tumor growth in mice and IL-7 did not alter cell sensitivity to OXP in culture. The antitumor effect of combining IL-7 and OXP correlated with a marked increase in the number of tumor-infiltrating activated CD8+ T cells and a marked decrease in the number of regulatory T (Treg) cells in spleen. Our data suggest that OXP plus IL-7 treatment inhibits tumor cell growth by immunoregulation rather than direct cytotoxicity. Our findings justify further evaluation of combining IL-7 and chemotherapy as a novel experimental cancer therapy.     

Continuous infusion of interleukin-2 and cyclophosphamide as treatment of advanced cancers: a National Biotherapy Study Group Trial

We have evaluated the effect of Interleukin-2 [IL-2] after Cyclophosphamide (C) chemotherapy in 41 patients with metastatic cancer. IL-2 was given as a continuous infusion priming cycle 36 hours after C at 1 gm/m2 intravenously. In 39 evaluable patients, there were no complete remissions [CR], 2 partial remissions [PR], and 1 had a minor response [MR]. Stable disease for 30 days was seen in 16 patients whereas 20 progressed. The durations of partial and minor responses were brief, ranging from 1-6 months. Grade 3-4 neutropenia was seen in 41%. This was more severe than seen with IL-2 alone or IL-2 combined with lower doses of C. The marrow suppression was due to the chemotherapy. This combination of IL-2 and C appears to be reasonably well tolerated by patients, but toxicity is greater and the response rate is no better than results achieved by IL-2 alone. Responses of 26 patients with renal cancer appear to be inferior to our historical data using IL-2/LAK cells without C. Immune monitoring demonstrated changes expected with C chemotherapy (i.e., a non-selective decline in immune function). C induced no further differences in IL-2 induced changes in immune function.     

Combination of two fiber-mutant adenovirus vectors, one encoding the chemokine FKN and another encoding cytokine interleukin 12, elicits notably enhanced anti-tumor responses

For achieving optimal cancer immunotherapy, it is anticipated that both the activation and infiltration of immune cells into tumor are indispensable. In the present study, fiber-mutant adenovirus vectors (Ad) encoding chemokine FKN, (AdRGD-FKN), and cytokine interleukin 12, (AdRGD-IL-12), were constructed. The in vivo gene expression of AdRGD was confirmed and the combination of both FKN and IL-12 encoding Ad elicited synergistic anti-tumor activity in ovarian carcinoma, which induced tumor regression in all tumor-bearing mice, while using FKN alone did not show notable tumor-suppressive effect. The treatment with both IL-12 and FKN induced long-term specific immunity against OV-HM tumors in tumor-rejected mice. The results of immunohistochemical staining for CD3(+ )and perforin-positive cells suggested that the failure of using FKN alone was because of the inactivation of infiltrated immune cells. In contrast, cotransduction with IL-12 and FKN could induce more activated tumor-infiltrating immune cells than that transducted with FKN or IL-12 alone. The results indicated that using both chemokine and cytokine might be a powerful tool and a promising way for effective cancer immunotherapy.     

Sodium stibogluconate interacts with IL-2 in anti-Renca tumor action via a T cell-dependent mechanism in connection with induction of tumor-infiltrating macrophages

IL-2 therapy results in 10-20% response rates in advanced renal cell carcinoma (RCC) via activating immune cells, in which the protein tyrosine phosphatase Src homology 2 domain-containing phosphatase 1 (SHP-1) is a key negative regulator. Based on finding that sodium stibogluconate (SSG) inhibited SHP-1, the anti-RCC potential and action mechanism of SSG and SSG/IL-2 in combination were investigated in a murine renal cancer model (Renca). Despite its failure to inhibit Renca cell proliferation in cultures, SSG induced 61% growth inhibition of Renca tumors in BALB/c mice coincident with an increase (2-fold) in tumor-infiltrating macrophages (Mphi). A combination of SSG and IL-2 was more effective in inhibiting tumor growth (91%) and inducing tumor-infiltrating Mphi (4-fold), whereas IL-2 alone had little effect. Mphi increases were also detected in the spleens of mice treated with SSG (3-fold) or SSG/IL-2 in combination (6-fold), suggesting a systemic Mphi expansion similar to those in SHP-deficient mice. T cell involvement in the anti-Renca tumor action of the combination was suggested by the observations that the treatment induced spleen IFN-gamma T cells in BALB/c mice, but failed to inhibit Renca tumor growth in athymic nude mice and that SSG treatment of T cells in vitro increased production of IFN-gamma capable of activating tumoricidal Mphi. The SSG and SSG/IL-2 combination treatments were tolerated in the mice. These results together demonstrate an anti-Renca tumor activity of SSG that was enhanced in combination with IL-2 and functions via a T cell-dependent mechanism with increased IFN-gamma production and expansion/activation of Mphi. Our findings suggest that SSG might improve anti-RCC efficacy of IL-2 therapy by enhancing antitumor immunity.     

Local therapy of cancer with free IL-2

This is a position paper about the therapeutic effects of locally applied free IL-2 in the treatment of cancer. Local therapy: IL-2 therapy of cancer was originally introduced as a systemic therapy. This therapy led to about 20% objective responses. Systemic therapy however was very toxic due to the vascular leakage syndrome. Nevertheless, this treatment was a break-through in cancer immunotherapy and stimulated some interesting questions: Supposing that the mechanism of IL-2 treatment is both proliferation and tumoricidal activity of the tumor infiltrating cells, then locally applied IL-2 should result in a much higher local IL-2 concentration than systemic IL-2 application. Consequently a greater beneficial effect could be expected after local IL-2 application (peritumoral = juxtatumoral, intratumoral, intra-arterial, intracavitary, or intratracheal = inhalation). Free IL-2: Many groups have tried to prepare a more effective IL-2 formulation than free IL-2. Examples are slow release systems, insertion of the IL-2 gene into a tumor cell causing prolonged IL-2 release. However, logistically free IL-2 is much easier to apply; hence we concentrated in this review and in most of our experiments on the use of free IL-2. Local therapy with free IL-2 may be effective against transplanted tumors in experimental animals, and against various spontaneous carcinomas, sarcomas, and melanoma in veterinary and human cancer patients. It may induce rejection of very large, metastasized tumor loads, for instance advanced clinical tumors. The effects of even a single IL-2 application may be impressive. Not each tumor or tumor type is sensitive to local IL-2 application. For instance transplanted EL4 lymphoma or TLX9 lymphoma were not sensitive in our hands. Also the extent of sensitivity differs: In Bovine Ocular Squamous Cell Carcinoma (BOSCC) often a complete regression is obtained, whereas with the Bovine Vulval Papilloma and Carcinoma Complex (BVPCC) mainly stable disease is attained. Analysis of the results of local IL-2 therapy in 288 cases of cancer in human patients shows that there were 27% Complete Regressions (CR), 23% Partial Regressions (PR), 18% Stable Disease (SD), and 32% Progressive Disease (PD). In all tumors analyzed, local IL-2 therapy was more effective than systemic IL-2 treatment. Intratumoral IL-2 applications are more effective than peritumoral application or application at a distant site. Tumor regression induced by intratumoral IL-2 application may be a fast process (requiring about a week) in the case of a highly vascular tumor since IL-2 induces vascular leakage/edema and consequently massive tumor necrosis. The latter then stimulates an immune response. In less vascular tumors or less vascular tumor sites, regression may require 9–20 months; this regression is mainly caused by a cytotoxic leukocyte reaction. Hence the disadvantageous vascular leakage syndrome complicating systemic treatment is however advantageous in local treatment, since local edema may initiate tumor necrosis. Thus the therapeutic effect of local IL-2 treatment is not primarily based on tumor immunity, but tumor immunity seems to be useful as a secondary component of the IL-2 induced local processes. If local IL-2 is combined with surgery, radiotherapy or local chemotherapy the therapeutic effect is usually greater than with either therapy alone. Hence local free IL-2 application can be recommended as an addition to standard treatment protocols. Local treatment with free IL-2 is straightforward and can readily be applied even during surgical interventions. Local IL-2 treatment is usually without serious side effects and besides minor complaints it is generally well supported. Only small quantities of IL-2 are required. Hence the therapy is relatively cheap. A single IL-2 application of 4.5 million U IL-2 costs about 70 Euros. Thus combined local treatment may offer an alternative in those circumstances when more expensive forms of treatment are not available, for instance in resource poor countries.     

In vivo antitumor efficacy of interleukin-21 in combination with chemotherapeutics

Interleukin-21 (IL-21) is a class I cytokine with antitumor properties due to enhanced proliferation and effector function of CD8⁺ T cells and natural killer (NK) cells. Here we have explored the magnitude and time-course of cytostatics-induced lymphopenia in mice and investigated whether treatment with cytostatics influences the antitumor effect of IL-21 in mouse tumor models. We show that pegylated liposomal doxorubicin (PLD), irinotecan and oxaliplatin induced transient lymphopenia, whereas 5-fluorouracil (5-FU) transiently increased lymphocyte counts. B cells were more sensitive than T cells towards irinotecan and oxaliplatin. Additive antitumor effects were observed after combining IL-21 with PLD, oxaliplatin and to less extent 5-FU but not irinotecan, and larger effect was observed when IL-21 administration was postponed relative to chemotherapy, suggesting that these agents may transiently impair immune function. However, the chemotherapies did not significantly alter the levels of circulating regulatory T cells and only marginally affected the ability of CD8⁺ T cells to respond to IL-21 measured as increased granzyme B mRNA. Our results show that IL-21 therapy can be successfully combined with agents from different chemotherapeutic drug classes, i.e. topoisomerase II inhibitors (PLD), anti-metabolites (5-FU) and platinum analogs (oxaliplatin) provided that IL-21 therapy is delayed relative to chemotherapy.     

In vivo antitumor efficacy of interleukin-21 in combination with chemotherapeutics

Interleukin-21 (IL-21) is a class I cytokine with antitumor properties due to enhanced proliferation and effector function of CD8⁺ T cells and natural killer (NK) cells. Here we have explored the magnitude and time-course of cytostatics-induced lymphopenia in mice and investigated whether treatment with cytostatics influences the antitumor effect of IL-21 in mouse tumor models. We show that pegylated liposomal doxorubicin (PLD), irinotecan and oxaliplatin induced transient lymphopenia, whereas 5-fluorouracil (5-FU) transiently increased lymphocyte counts. B cells were more sensitive than T cells towards irinotecan and oxaliplatin. Additive antitumor effects were observed after combining IL-21 with PLD, oxaliplatin and to less extent 5-FU but not irinotecan, and larger effect was observed when IL-21 administration was postponed relative to chemotherapy, suggesting that these agents may transiently impair immune function. However, the chemotherapies did not significantly alter the levels of circulating regulatory T cells and only marginally affected the ability of CD8⁺ T cells to respond to IL-21 measured as increased granzyme B mRNA. Our results show that IL-21 therapy can be successfully combined with agents from different chemotherapeutic drug classes, i.e. topoisomerase II inhibitors (PLD), anti-metabolites (5-FU) and platinum analogs (oxaliplatin) provided that IL-21 therapy is delayed relative to chemotherapy.     

Enhancement in therapeutic efficacy of miltefosine in combination with synthetic bacterial lipopeptide, Pam3Cys against experimental Visceral Leishmaniasis

Existing drugs for visceral leishmaniasis (VL) are partially effective, toxic, having high cost and long term treatment. Their efficacies are also compromised due to suppression of immune function associated during the course of infection. Combination therapy including a potential and safe immunostimulant with lower doses of effective drug has proven as a significant approach which is more effective than immunotherapy or drug therapy alone. In the present study, we have used the combination of Pam3Cys (an in-built immunoadjuvant and TLR2 ligand) and miltefosine. Initially dose optimization of both the agents was carried out and after that, antileishmanial effect of their combination was evaluated. All experiments were done in BALB/c mouse model. The immunomodulatory role of Pam3Cys on the immune functions of the host receiving combination treatment was also determined using immunological and biochemical parameters viz. phagocytosis, Th1/Th2 cytokines and production of ROS, RNS and H(2)O(2). Combination group showed significant enhancement in parasitic inhibition as compared to groups receiving miltefosine and Pam3Cys separately. Enhanced production of Th1 cytokines as well as ROS, RNS and H(2)O(2) was witnessed during the study of immunological alterations. Remarkable increase in phagocytosis index was also observed. Thus, the risk of development of drug resistance against miltefosine can be resolved through using low doses of it and Pam3Cys (single-dose) in combination and also provide a promising alternative for cure of leishmaniasis, with a pronounced transformation of the host immune response.     

Antitumor effect of intratumoral administration of dendritic cell combination with vincristine chemotherapy in a murine fibrosarcoma model

A new antitumor therapeutic strategy utilizing the combined effect of chemotherapy and DC (dendritic cell)-based immunotherapy was designed, and the effect of intratumoral injections of unpulsed, immature DCs was evaluated after in vivo pretreatment of vincristine on tumor growth in a murine fibrosarcoma tumor model. Vincristine exerted a much more potent apoptosis/necrosis-inducing effect on MCA-102 tumor cells than on DCs both in vitro and in vivo. Moreover, CD11c, CD40, CD80 and CD86 molecules on DCs were not downregulated after treatment with vincristine either in vitro or in vivo. The growth of tumor significantly regressed in the group which received the combined vincristine chemotherapy with intratumoral administration of DCs in contrast to the untreated group, the group treated with DCs alone, and the group treated with vincristine alone. In particular, an upregulated expression of CD40, CD80 and CD86 molecules on DCs was found in the combination treatment group. Furthermore, the number of CD4+ and CD8+ T cells and the staining intensity of their CD4 and CD8 surface molecules also increased after the combination treatment. Therefore, our results indicate the feasibility of this combination therapy with vincristine chemotherapy and DC-based immunotherapy as an efficient antitumor strategy for the treatment of fibrosarcoma.     

IL-2 complex recovers steroid-induced inhibition in immunochemotherapy for head and neck cancer

Background: A combination therapy with immune checkpoint inhibitors (ICIs) and platinum-based chemotherapy has become the first-line treatment for recurrent or metastatic head and neck squamous carcinoma (HNSCC). Although steroids are often used as anti-emetic medications during chemotherapy, their adverse effects on immune-combined chemotherapy are unclear in HNSCC.Methods: The effects of dexamethasone on tumor growth and immune cell population were evaluated in a mouse HNSCC model treated with PD-1 blockade combined with cisplatin. The effect of various doses of dexamethasone on cell proliferation, survival, surface markers, IFN-γ production, and antitumor effects in antigen-specific T cells was examined in vitro. The recovery of T cell dysfunction by IL-2 was assessed in vitro and in vivo.Results: In a mouse HNSCC model, dexamethasone showed limited antitumor effects on immunochemotherapy. Dexamethasone decreased the number of T cells and inhibited T cell differentiation into effector and central memory T cells. In the in vitro assessment, dexamethasone induced cell death, limited proliferation, and reduced the reactivity against HNSCC cell lines of antigen-specific T cells in a dose-dependent manner. The expression of inhibitory receptors on T cells was not affected by steroids. This inhibition was recovered by IL-2 and IL-2/anti-IL-2 complexes (IL-2 Cx) in vitro and in vivo, respectively.Conclusion: Our preclinical data indicate that dexamethasone diminishes the antitumor effects of immunochemotherapy in patients with HNSCC. IL-2 Cx recovered the inhibition of antitumor immunity by steroids and might be a potent immune adjuvant for patients who require steroids during PD-1 blockade and chemotherapy.     

Modulation of hematologic and immunologic effects of high dose chemotherapy by interleukin-2 in a murine tumor model.

To determine if intensive chemotherapy consisting of cyclophosphamide (C), etoposide (E), and cisplatin (P) (CEP) may be usefully combined with recombinant human interleukin-2 (rhIL-2), we examined a murine tumor model designed to approximate a common clinical situation: macroscopic, drug-resistant cancer. Using C57BL/6 mice with extensive tumor burden 10 days after intravenous B16 melanoma cell injection, we observed (1) C, E, and P synergize to enhance survival but do not cure mice at the highest tolerable dose (C = 200 mg/kg, E = 60 mg/kg, and P = 3 mg/kg); (2) rhIL-2 at 3 x 10(5) U (subcutaneously) daily for 4 days administered 10-18 days after B16 injection significantly improves survival; (3) CEP plus rhIL-2 is more effective than CEP alone only when rhIL-2 is administered before CEP; (4) CEP suppresses IL-2-induced lymphokine-activated killer cell activity in the spleen; and (5) rhIL-2 protects mice incompletely from the immunologic and hematologic suppression of CEP. Our results suggest that intensive chemotherapy combined with rhIL-2 may be beneficial. The success of any such combination may be schedule dependent.     

Chemo-adoptive immunotherapy of nude mice implanted with human colorectal carcinoma and melanoma cell lines

Summary The antitumor effects of chemotherapy, recombinant human interleukin-2 (IL-2), recombinant human interferon A/D (IFN), allogeneic human lymphokine-activated killer (LAK) cells, and antitumor monoclonal antibody (mAb), administered alone and in various combinations, were tested in athymic nude mice carrying human tumor xenografts. Treatment began 6–18 days after i.v. or i.p. inoculation of colorectal carcinoma or melanoma cell lines, when macroscopic growths were evident. Chemotherapy consisted of two or three courses of 5-fluorouracil (5-FU) or dacarbazine. IL-2 and/or IFN were administered three to five times weekly for 1–3 weeks, usually starting 2–5 days after chemotherapy. Human LAK cells were infused once or twice weekly for 2 or 3 weeks concurrently with IL-2. In some experiments, murine anticolorectal carcinoma mAb (SF25) was administered. In both tumor systems, chemotherapy alone or immunotherapy alone (IL-2, IL-2 + LAK cells, IFN, IL-2 + IFN ± LAK cells) had little or no therapeutic effects. Additive effects were obtained by combining chemotherapy with IL-2 and LAK cells or with IL-2 and IFN. In the majority of the experiments, the most effective combination was chemotherapy + IL-2 + IFN + LAK cells. Treatment with mAb was beneficial in the colorectal carcinoma system when combined with 5-FU + IL-2 or 5-FU + IL-2 + IFN. Homing experiments with radiolabeled human and mouse LAK cells injected i.v. showed increased early accumulation in the liver and lungs, whereas freshly explanted mouse splenocytes localized mostly in the spleen and liver. The tissue distribution pattern of human LAK cells was similar in normal and tumor-bearing mice (with lung metastases). These findings suggest that combination of chemotherapy with cytokines and LAK cells can be partially effective for advanced solid human tumors even in the absence of the host's T-cell immune response. Preliminary experiments showed that tumor-specific, anti-melanoma T-cell clones were effective in local (s.c.) tumor growth inhibition (Winn assay) following coinjection with the autologous tumor cells.     

Successful adoptive immunotherapy with vaccine-sensitized T cells,despite no effect with vaccination alone in a weakly immunogenic tumor model

Tumor cell vaccines have been successful at inducing immunity in naïve mice, but only in a few reports has vaccination alone induced regression of established tumors and, generally, only when they are very small. Clinically, vaccinations alone may not be able to cause regression of established human cancers, which tend to be weakly immunogenic. We hypothesized that pharmacologic ex vivo amplification of a vaccination-induced immune response with subsequent adoptive immunotherapy (AIT) to tumor-bearing animals would be more effective in treatment of these animals than vaccination alone. The 4T1 and 4T07 mammary carcinomas are derived from the same parental cell line, but 4T1 is much less immunogenic and more aggressive than 4T07. Vaccination with either 4T1, 4T1-IL-2, or 4T07-IL-2 was not effective as treatment for established 4T1 tumors. However, 4T1 or 4T07-IL-2-vaccine-sensitized draining lymph node (DLN) cells, activated ex vivo with bryostatin 1 and ionomycin and expanded in culture, induced complete tumor regressions when adoptively transferred to 4T1 tumor-bearing animals. This was effective against small tumors as well as more advanced tumors, 10 days after tumor cell inoculation. Furthermore, as would be required for this approach to be used clinically, vaccine-DLN cells obtained from mice with established progressive 4T1 tumors (inoculated 10 days before vaccination) also induced regression of 4T1 tumors in an adoptive host. In none of these experiments was exogenous IL-2 required to induce tumor regression. The response to tumor cell vaccine can be amplified by ex vivo pharmacologic activation of sensitized T cells, which can then cure an established, weakly immunogenic and highly aggressive tumor that was resistant to vaccination alone.     

Interleukin-21 Enhances Rituximab Activity in a Cynomolgus Monkey Model of B Cell Depletion and in Mouse B Cell Lymphoma Models

Rituximab, a monoclonal antibody targeting CD20 on B cells, is currently used to treat many subtypes of B cell lymphomas. However, treatment is not curative and response rates are variable. Recombinant interleukin-21 (rIL-21) is a cytokine that enhances immune effector function and affects both primary and transformed B cell differentiation. We hypothesized that the combination of rIL-21 plus rituximab would be a more efficacious treatment for B cell malignancies than rituximab alone. We cultured human and cynomolgus monkey NK cells with rIL-21 and found that their activity was increased and proteins associated with antibody dependent cytotoxicity were up-regulated. Studies in cynomolgus monkeys modeled the effects of rIL-21 on rituximab activity against CD20 B cells. In these studies, rIL-21 activated innate immune effectors, increased ADCC and mobilized B cells into peripheral blood. When rIL-21 was combined with rituximab, deeper and more durable B cell depletion was observed. In another series of experiments, IL-21 was shown to have direct antiproliferative activity against a subset of human lymphoma cell lines, and combination of murine IL-21 with rituximab yielded significant survival benefits over either agent alone in xenogeneic mouse tumor models of disseminated lymphoma. Therefore, our results do suggest that the therapeutic efficacy of rituximab may be improved when used in combination with rIL-21.     

小鼠体内转染CH50多肽真核表达载体趋化免疫细胞在肿瘤治疗中的作用

目的 研究体内转染表达CH50多肽对免疫细胞的趋化,聚集作用,探讨趋化聚集的免疫细胞增强抗肿瘤以及化疗后抗肿瘤的免疫力。方法 分别在小鼠后肢肌肉,接种肿瘤组织或化疗的肿瘤组织内注射pCH510质粒进行转染,取转染部位组织制备石蜡切片,观察免疫细胞的聚集情况,并观察转染pCH510及联合化疗对肿瘤的治疗作用。结果 正常小鼠后肢肌肉转染pCH510后,注射部位有大量免疫细胞聚集,其中主要是巨噬细胞,淋巴细胞,中性粒细胞,聚集的免疫细胞至少持续存在一周,肿瘤部位转染后,趋化聚集的免疫细胞分布于肿瘤组织周围,抑制了肿瘤细胞的生长,化疗后转染,仍有趋化聚集免疫细胞的作用。免疫细胞聚集数量相对只转染pCH510虽有所减少,但对肿瘤的抑制作用明显增强。结论 本文结果提示,在小鼠体内转染pCH510表达的CH50多肽不仅能够趋化免疫细胞,提高局部抗肿瘤的免疫力,而且与化疗联合作用在肿瘤治疗中具有更大的研究潜力。     

Immunotherapy of intraperitoneal cancer with interleukin 2 and lymphokine-activated killer cells reduces tumor load and prolongs survival in murine models

The control of malignancy disseminated within the peritoneal cavity is an important problem in the management of low-grade gastrointestinal and ovarian neoplasms. A model of peritoneal carcinomatosis in the mouse was used to investigate the potential of lymphokine-activated killer (LAK) cells and exogenous interleukin 2 (IL-2) to control intraperitoneal tumor. LAK cells are splenocytes activated in vitro by IL-2. C57BL/6 mice were injected intraperitoneally with a lethal inoculum of syngeneic MCA-105 tumor. Three days later, the established tumor was treated with adoptively transferred LAK cells and/or exogenous IL-2 administration. LAK cells alone were ineffective in reducing intraperitoneal tumor. Administration of IL-2 alone resulted in limited tumor reduction. Treatment with exogenous IL-2 in conjunction with LAK cells resulted in the greatest reduction of intraperitoneal tumor. The larger the number of LAK cells given, the greater the reduction in tumor. Frequent intraperitoneal bolus administration of IL-2 was more effective than a single daily intraperitoneal injection and intraperitoneal administration of IL-2 and LAK was more effective than systemic treatments. Marked prolongation of life was seen in mice treated with LAK cells plus exogenous IL-2. We conclude that intraperitoneal LAK cells plus exogenous IL-2 is an effective treatment regimen for reducing intraperitoneal tumor in this murine model.     

双歧异黄酮奶粉对H22荷瘤小鼠化疗后的增效减毒作用研究

目的研究双歧异黄酮奶粉对环磷酰胺化疗后H22荷瘤小鼠抗肿瘤的增效减毒作用及其机制。方法构建H22荷瘤C57BL／6小鼠模型,研究双歧异黄酮奶粉对环磷酰胺化疗后的抑瘤率,取脾和胸腺计算脏器指数,双抗夹心ELISA法测定抑癌基因P27的表达及IL-2的水平以探索增效减毒机制。结果双歧异黄酮奶粉与环磷酰胺联合抗肿瘤具有增效减毒作用。可诱导抑癌基因P27的表达,增加IL-2的水平。结论双歧异黄酮奶粉与环磷酰胺联合抗肿瘤具有增效减毒作用。     

The tumor immunosuppressive microenvironment impairs the therapy of anti-HER2/neu antibody

It has been well established that immune surveillance plays critical roles in preventing the occurrence and progression of tumor. More and more evidence in recent years showed the host anti-tumor immune responses also play important roles in the chemotherapy and radiotherapy of cancers. Our previous study found that tumor- targeting therapy of anti-HER2/neu mAb is mediated by CD8⁺ T cell responses. However, we found here that enhancement of CD8⁺ T cell responses by combination therapy with IL-15R/IL-15 fusion protein or anti-CD40, which are strong stimultors for T cell responses, failed to promote the tumor therapeutic effects of anti-HER2/neu mAb. Analysis of tumor microenviornment showed that tumor tissues were heavily infiltrated with the immunosuppressive macrophages and most tumor infiltrating T cells, especially CD8⁺ T cells, expressed high level of inhibitory co-signaling receptor PD-1. These data suggest that tumor microenvironment is dominated by the immunosuppressive strategies, which thwart anti-tumor immune responses. Therefore, the successful tumor therapy should be the removal of inhibitory signals in the tumor microenvironment in combination with other therapeutic strategies.     

Granulocyte-monocyte colony-stimulating-factor augments the interleukin-2-induced cytotoxic activity of human lymphocytes in the absence and presence of mouse or chimeric monoclonal antibodies (mAb 17-1A)

Summary Blood lymphocytes stimulated for 96 h with interleukin-2 (IL-2; 100 BRMP U/ml) (lymphokine-activated killer, LAK, cells) or granulocyte-monocyte colonystimulating-factor (GM-CSF) (10 ng/ml) became cytotoxic for Daudi cells. IL-2 was significantly more effective than GM-CSF. Only IL-2-activated cells killed SW948 (a human colorectal carcinoma cell line) while GM-CSF-stimulated cell did not. GM-CSF and IL-2 acted synergistically in a dose-dependent fashion for induction of a highly effective cytotoxic cell population (IL-2/GM-CSF cells). Il-2/GM-CSF cells were statistically significantly more effective than LAK cells in lysing Daudi cells and SW948 (P <0.05). The enhancing effect was most pronounced during the first 48–96 h of activation. Incubation periods longer than 192 h did not contribute to augmented cytotoxicity. The combination of IL-2 and GM-CSF significantly increased the number of CD25⁺ cells compared to IL-2 and GM-CSF alone. Furthermore, IL-2/GM-CSF cells were significantly more effective in antibody-dependent cellular cytotoxicity assays (SW948 + mAb 17-1A) than LAK cells. The chimeric mAb 17-1A was significantly more effective in tumor cell lysis than the mouse mAb. Thus, combination of various biological therapeutics might be a way to enhance their antitumoral effects.     

Effect of chemotherapy on NK function in the peripheral blood of cancer patients

Summary The effects of cytotoxic chemotherapy on NK cell function and on glass adherent cell regulation of NK cell function was evaluated in the peripheral blood mononuclear cells of 20 previously untreated solid tumor patients. Most of the patients studied had lung cancer and received one of four combination chemotherapy treatment regimens. In addition, one patient with colon carcinoma and one patient with melanoma were studied, each of whom received treatment with a single agent. The results demonstrated that chemotherapy exerted a differential influence on NK activity which correlated with the pretreatment NK level of function in the individual patient. In patients with depressed NK levels prior to treatment, chemotherapy augmented NK function; in patients with normal levels prior to treatment, chemotherapy depressed NK function. The effects observed appeared to be associated with the capacity of chemotherapy to influence glass adherent cell regulation of NK activity. There was no apparent correlation between the effects of chemotherapy on numbers of NK effector cells, Leu11+ cells, or latex-ingesting cells. Also, there was no correlation between the effects seen and the type of drug treatment that was administered; rather, this was dependent on the pretreatment NK level of function which in turn was associated with glass adherent cell regulation of NK function.Supported in part by PHS Grant No. 27598