Anti-ganglioside GM2 monoclonal antibody-dependent killing of human lung cancer cells by lymphocytes and monocytes

Genetically engineered humanized anti-ganglioside GM2 antibody against multiple organ metastasis produced by GM2-expressing small-cell lung cancer cells

Small-cell lung cancer (SCLC) grows rapidly and metastasizes to multiple organs. We examined the antimetastatic effects of the humanized anti-ganglioside GM2 (GM2) antibodies, BIW-8962 and KM8927, compared with the chimeric antibody KM966, in a SCID mouse model of multiple organ metastases induced by GM2-expressing SCLC cells. BIW-8962 and KM8927 induced higher antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity than KM966 against the GM2-expressing SCLC cell line SBC-3 in vitro. These humanized antibodies inhibited the production of multiple organ metastases, increased the number of apoptotic cells, and prolonged the survival of the SCID mice. Histological analyses using clinical specimens showed that SCLC cells expressed GM2. These findings suggest that humanized anti-GM2 antibodies could be therapeutically useful for controlling multiple organ metastases of GM2-expressing SCLC.

Chimeric and humanized anti-HM1.24 antibodies mediate antibody-dependent cellular cytotoxicity against lung cancer cells

HM1.24 antigen (CD317) was originally identified as a cell surface protein that is preferentially overexpressed on multiple myeloma cells. Immunotherapy using anti-HM1.24 antibody has been performed in patients with multiple myeloma as a phase I study. The aim of this study was to evaluate the anti-tumor activity of mouse-human chimeric and humanized anti-HM1.24 monoclonal antibodies (mAbs) against lung cancer cells in vitro. Human peripheral blood lymphocytes and monocytes separated from mononuclear cells (PBMCs) were used as effector cells. Antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) of chimeric and humanized anti-HM1.24 mAbs against lung cancer cells were determined by chromium-release assay. In some experiments, target or effector cells were pretreated with various cytokines. Chimeric and humanized anti-HM1.24 mAbs effectively induced ADCC against lung cancer cells mediated more efficiently by lymphocytes than monocytes. The cytotoxic activity correlated with the level of HM1.24 expression on lung cancer cells. Natural killer cells were identified as the major effector cells in ADCC mediated by the anti-HM1.24 mAb. The treatment of lymphocytes or monocytes with IL-2, IL-12, IL-15, M-CSF, or IFN-gamma significantly increased the ADCC activity. Moreover, the culture of lung cancer cells with IFN-beta or IFN-gamma augmented their susceptibility to ADCC and CDC. PBMCs from patients with lung cancer induced a level of ADCC comparable to that induced by PBMCs from healthy donors. Chimeric or humanized anti-HM1.24 mAbs have potential as a new therapeutic tool in lung cancer, and in combination with interleukins and interferons, could be useful for enhancing ADCC.

Immunological circumvention of multiple organ metastases of multidrug resistant human small cell lung cancer cells by mouse-human chimeric anti-ganglioside GM2 antibody KM966

serum against SBC-3/DOX cells to a similar extent compared with parental SBC-3 cells. Pretreatment of human effector cells with various cytokines induced further enhancement of the KM966-dependent ADCC against SBC-3/DOX cells. Intravenous injection of SBC-3 or SBC-3/DOX cells into natural killer (NK) cell-depleted severe combined immunodeficient (SCID) mice developed metastases in multiple organs (liver, kidneys and lymph nodes). Interestingly, SBC-3/DOX cells produced metastases more rapidly than SBC-3 cells, suggesting more aggressive phenotype of SBC-3/DOX cells than their parental cells in vivo. Systemic treatment with KM966, given on days 2 and 7, drastically inhibited the formation of multiple-organ metastases produced by both SBC-3 and SBC-3/DOX cells, indicating that KM966 can eradicate metastasis by SCLC cells irrespective of MDR phenotype. These findings suggest that the mouse-human chimeric KM966 targets the GM2 antigen, and might be useful for the immunological circumvention of multiple-organ metastases of refractory SCLC.

Humanized anti-ganglioside GM2 antibody is effective to induce antibody-dependent cell-mediated cytotoxicity in mononuclear cells from lung cancer patients

Ganglioside GM2 is one of the major gangliosides expressed on the cell surface of human tumors including lung cancer. We have previously reported that a mouse-human chimeric monoclonal antibody (mAb), KM966, against GM2 promotes the lysis of lung cancer cells by human blood mononuclear cells (MNC) of healthy donors. In this study, we examined antibody-dependent cell-mediated cytotoxicity (ADCC) of MNC, using KM966 mAb and its humanized counterpart, KM8969, in 16 lung cancer patients and 18 control patients. The ADCC activity was assessed by 4-h (51)Cr release from GM2 positive SBC-3 small cell lung cancer cells. MNC from lung cancer patients exhibited similar ADCC activity to those from control patients when KM966 and KM8969 were used as mAb. Moreover, effective ADCC activity was observed even in MNC from advanced lung cancer patients. These observations suggest the potential activity of humanized anti-GM2 mAb (KM8969), as well as chimeric KM966, in biological therapy for lung cancer patients.

Antibody-dependent cytotoxicity mediated by chimeric monoclonal antibody Nd2 and experimental immunotherapy for pancreatic cancer

In a previous study, mouse monoclonal antibody (MoAb) Nd2 (m-Nd2, mouse IgG1) labeled with (131)I exhibited efficacy in in vivo radioimmunotherapy against pancreatic cancer. In this study we prepared mouse / human chimeric antibody Nd2 (c-Nd2, human IgG1) for clinical use and examined whether c-Nd2 induced antibody-dependent cell-mediated cytotoxicity (ADCC). Cytotoxicity to pancreatic cancer (PC) cell lines, including Nd2 antigen-positive (SW1990, RWP-1, Capan-1) and Nd2 antigen-negative (Panc-1, MiaPaca-2, Capan-2) lines, was evaluated by mixed human leukocyte and tumor cell culture (MLTC) at an effector cell to target cell (E / T) ratio of 50 with or without Nd2. Cytotoxicities to SW1990 with no antibody, m-Nd2 and c-Nd2 (1 microg / ml) were 26.7%, 38.0% and 55%, respectively; to RWP-1, 28%, 41% and 70%; to Capan-1, 26%, 30% and 52%; to Panc-1, 24%, 28% and 30%; to MiaPaca-2, 18%, 20% and 27% and to Capan-2, 29. 7%, 35.0% and 40.6%. Cytotoxic capacity during MLTC with c-Nd2 was significantly higher than during MLTC with m-Nd2 or with no antibody. These findings indicated that cytotoxicity to Nd2-positive PC cells during MLTC is induced by ADCC. Intraperitoneal injection of c-Nd2 inhibited the tumor growth of SW1990 xenografted subcutaneously in nude mice and prolonged the survival of nude mice in which SW1990 tumor was transplanted orthotopically at the tail of the pancreas. These findings suggested that, because of its ability to induce ADCC, c-Nd2 may be clinically useful for the immunotherapeutic treatment of pancreatic cancer.

Augmentation of 17-1A-induced antibody-dependent cellular cytotoxicity by the triple cytokine combination of interferon-alpha, interleukin-2, and interleukin-12

Previously, interferon-alpha (IFN-alpha), interleukin-2 (IL-2), and interleukin-12 (IL-12) were shown to increase the antibody-dependent cellular cytotoxicity (ADCC) induced by the murine monoclonal antibody 17-1A, which recognizes the tumor-associated antigen EpCAM. In this study, the authors wanted to determine whether the combination of these three cytokines would yield greater cytotoxicity than the single cytokines. For cytotoxicity assessment, a new flow cytometric assay was used that allows the analysis of long-term ADCC exerted by macrophages. Peripheral blood mononuclear cells from healthy donors were used as effector cells against the colorectal carcinoma cell line HT29 at a low effector-to-target ratio of 4.5:1. With this test, the effectiveness of the combinations IL-2 and IFN-alpha, IL-2 and IL-12, and IL-12 and IFN-alpha were compared with each other. The combinations IL-2 plus IL-12 and IFN-alpha plus IL-12 were more potent at the concentrations tested. Furthermore, the triple cytokine combination of IFN-alpha, IL-2, and IL-12 revealed significantly greater ADCC than dual cytokine combinations. Next, CD14+, CD4+, and CD4- cells were isolated by paramagnetic beads and magnetic activated cell sorter (MACS) columns. The CD14+ and CD4- cell populations contained the ADCC effectors. The addition of CD4+ cells to CD14+ or CD4- cells resulted in augmented ADCC, indicating that cooperation between immune cells occurs. These results suggest that multiple cytokine combinations with monoclonal antibodies may be more effective for cancer immunotherapy.

Effect of a chimeric anti-ganglioside GM2 antibody on ganglioside GM2-expressing human solid tumors in vivo

Ganglioside GM2 is expressed on the surface of neuroblastoma and glioblastoma cells, and may also be detected on lung cancer cells. We reported previously that anti-ganglioside GM2 antibody exhibited strong in vitro anti-tumor activity against adriamycin-resistant cancer cells, which overexpressed ganglioside GM2. In the present study, we examined the in vivo anti-tumor effect of the chimeric anti-ganglioside GM2 antibody, KM966, against human lung and breast carcinoma cells, SBC-3 and MCF-7, and respective adriamycin-resistant clones, SBC-3/ADM and AdrR MCF-7 in BALB/c nu/nu mice. Ratios of tumor volume (T/C) between KM966-treated group and control group were 0.01 for SBC-3, 0.00 for SBC-3/ADM, 0.85 for MCF-7 and 0.34 for AdrR MCF-7 cells, respectively. Nude mice, which were pretreated with anti-asialo GM1 antibody to remove natural killer cells, were transplanted with 4 x 10(7) of SBC-3 and SBC-3/ADM subcutaneously. Seven days later, when tumors had grown to a diameter of over 8 mm, mice began to receive intravenous treatment of 120 microgram/mouse KM966 daily. Fourteen daily treatments induced regression to less than 4-mm diameter in 4/5 SBC-3 tumors and 5/5 of SBC-3/ADM tumors. All SBC-3/ADM tumors disappeared completely, suggesting that KM966 exerts a strong in vivo anti-tumor effect on ganglioside GM2-expressing cancer cells. In KM966-treated mice, the surface of the tumor cells stained positive with anti-human IgG. In addition, numerous leukocytes had infiltrated into the tumor mass. Antibody-dependent cell-mediated cytotoxicity (ADCC) of KM966 against tumor cells was examined in vitro by (51)Cr-release assay and revealed that KM966 induces ADCC activity against ganglioside GM2-expressing tumors. Our results suggest that immunotherapy using KM966 may be useful for the treatment of ganglioside GM2-expressing solid tumors.

Advances in cell separation: recent developments in counterflow centrifugal elutriation and continuous flow cell separation

Cell separation by counterflow centrifugal elutriation (CCE) or free flow electrophoresis (FFE) is performed at lower frequency than cell cloning and antibody-dependent, magnetic or fluorescence-activated cell sorting. Nevertheless, numerous recent publications confirmed that these physical cell separation methods that do not include cell labeling or cell transformation steps, may be most useful for some applications. CCE and FFE have proved to be valuable tools, if homogeneous populations of normal healthy untransformed cells are required for answering scientific questions or for clinical transplantation and cells cannot be labeled by antibodies, because suitable antibodies are not available or because antibody binding to a cell surface would induce the cell reaction which should be investigated on purified cells or because antibodies bound to the surface hamper the use of the isolated cells. In addition, the methods are helpful for studying the biological reasons for, or effects of, changes in cell size and cellular negative surface charge density. Although the value of the methods was confirmed in recent years by a considerable number of important scientific results, activities to further develop and improve the instruments have, unfortunately, declined.

Therapeutic efficacy of mouse-human chimeric anti-ganglioside GM2 monoclonal antibody against multiple organ micrometastases of human lung cancer in NK cell-depleted SCID mice

The development of distant metastases to multiple organs is a critical problem in the treatment of human lung cancer. In this study, we evaluated the therapeutic efficacy of a mouse-human chimeric anti-ganglioside GM2 (GM2) monoclonal antibody (MAb), KM966 against metastasis formation of GM2-positive human lung cancer cells inoculated intravenously (i.v.) into natural killer (NK) cell-depleted severe combined immunodeficient (SCID) mice. GM2-positive human small cell lung cancer (SCLC), SBC-3 cells (1 x 10(6)), injected through a tail vein into NK cell-depleted SCID mice, formed large number of metastatic colonies in the liver, kidneys and lymph nodes by 42 days after inoculation (day 42). KM966, but not control MAb, given on days 2 and 7, almost completely inhibited metastasis formation of SBC-3 cells in the liver, kidneys and lymph nodes in a dose-dependent fashion. Moreover, treatment with KM966 at advanced stages of metastasis (even from day 28) significantly suppressed multiple organ metastases of SBC-3 cells. The anti-metastatic effect of KM966 in vivo was mainly due to an antibody-dependent cell-mediated cytotoxicity (ADCC) reaction mediated by macrophages of the SCID mice. Our findings suggest that the mouse-human chimeric anti-GM2 MAb, KM966 may be useful for eradicating multiple organ micrometastases of lung cancer in humans.