CA 125 and OA 3 as target antigens for immunodiagnosis and immunotherapy in ovarian cancer

Prospects of chimeric antigen receptor T cell therapy in ovarian cancer

Despite advances in various chemotherapy regimens, current therapeutic options are limited for ovarian cancer patients. Immunotherapy provides a promising and novel treatment option for ovarian cancer. Recently, chimeric antigen receptor (CAR) T cell therapy has shown promising results in hematological tumors and current research is going on in various solid tumors like ovarian cancer. CAR T cells are genetically engineered T cells with major histocompatibility complex-independent, tumor-specific, immune-mediated cytolytic actions against cancer cells. Initial studies of CAR T cell therapy have shown promising results in ovarian cancer, but there are some obstacles like impaired T cell trafficking, lack of antigenic targets, cytokine release syndrome and most important immunosuppressive tumor microenvironment. Optimization of design, improving tumor microenvironment and combinations with other therapies may help us in improving CAR T cell efficacy. In this review article, we highlight the current knowledge regarding CAR T cell therapy in ovarian cancer. We have discussed basic functioning of CAR T cells, their rationale and clinical outcome in ovarian cancer with limitations.

Targeting AMPK signaling in combating ovarian cancers: opportunities and challenges

The development and strategic application of effective anticancer therapies have turned out to be one of the most critical approaches of managing human cancers. Nevertheless, drug resistance is the major obstacle for clinical management of these diseases especially ovarian cancer. In the past years, substantial studies have been carried out with the aim of exploring alternative therapeutic approaches to enhance efficacy of current chemotherapeutic regimes and reduce the side effects caused in order to produce significant advantages in overall survival and to improve patients' quality of life. Targeting cancer cell metabolism by the application of AMP-activated protein kinase (AMPK)-activating agents is believed to be one of the most plausible attempts. AMPK activators such as 5-aminoimidazole-4-carboxamide 1-β-d-ribofuranoside, A23187, metformin, and bitter melon extract not only prevent cancer progression and metastasis but can also be applied as a supplement to enhance the efficacy of cisplatin-based chemotherapy in human cancers such as ovarian cancer. However, because of the undesirable outcomes along with the frequent toxic side effects of most pharmaceutical AMPK activators that have been utilized in clinical trials, attentions of current studies have been aimed at the identification of replaceable reagents from nutraceuticals or traditional medicines. However, the underlying molecular mechanisms of many nutraceuticals in anticancer still remain obscure. Therefore, better understanding of the functional characterization and regulatory mechanism of natural AMPK activators would help pharmaceutical development in opening an area to intervene ovarian cancer and other human cancers.

Causal ACTH-Depot Therapy during Pregnancies following Infertility Treatment

The aim of this paper was to confirm the efficacy of adrenocorticotropin depot (ACTH-depot) therapy in pregnancies with threatened miscarriage and preterm delivery through the desired stimulation of the adrenal glands controlled by the rest of organism. The activity of hypothalamic-pituitary-adrenal axis plays a key role in pregnancy. Such naturally stimulated endogenous corticosteroid hormones are free from unwanted side effects of their synthetics analogs. Low level of maternal blood ACTH and insufficient increase of induced by hypothalamic hormones oxytocinases (cystine-β-aminopeptidases) were indication to ACTH-depot therapy (0.5 mg/week) in our consecutive prospective studies. Contrary to antenatal use of synthetic corticosteroids, there are no temporal limits of this therapy, which has to be more often recommended into clinical prevention of fetal morbidity, treatment of premature delivery, and finally elimination of the newborn's mortality caused by the neuroendocrinological gestoses.

Ovarian cancer immunotherapy: opportunities, progresses and challenges

Due to the low survival rates from invasive ovarian cancer, new effective treatment modalities are urgently needed. Compelling evidence indicates that the immune response against ovarian cancer may play an important role in controlling this disease. We herein summarize multiple immune-based strategies that have been proposed and tested for potential therapeutic benefit against advanced stage ovarian cancer. We will examine the evidence for the premise that an effective therapeutic vaccine against ovarian cancer is useful not only for inducing remission of the disease but also for preventing disease relapse. We will also highlight the questions and challenges in the development of ovarian cancer vaccines, and critically discuss the limitations of some of the existing immunotherapeutic strategies. Finally, we will summarize our own experience on the use of patient-specific tumor-derived heat shock protein-peptide complex for the treatment of advanced ovarian cancer.

Distribution of OV-TL 3 and MOv18 in normal and malignant ovarian tissue

AIMS

To analyse the distribution of OV-TL 3 and MOv18 in normal ovarian tissue to determine which antibody is most suitable for (radio)immunotherapy of ovarian carcinoma.

METHODS

The distribution of OV-TL 3 and MOv18 was determined using immunohistochemistry and flow cytometry.

RESULTS

Epithelial and other cells in many tissues, and leucocytes in peripheral blood, bone marrow and spleen stained positively with OV-TL 3. The staining pattern of MOv18 in normal tissues was more restricted and was confined to epithelial cells in the lung, kidney, pancreas, salivary gland, ovary, Fallopian tubes, and cervix. Reactivity was also observed with pneumocytes in the lung, tubuli in the kidney, acinar cells in the salivary gland and pancreas, in the placenta, and with Kupffer cells in the liver. The staining pattern of chimeric MOv18 was identical with the murine form. OV-TL 3 and MOv18 reacted with 100% and 98% (45/46) of the 46 tested epithelial ovarian cancers, respectively. In ovarian carcinoma tissue homogeneous staining of epithelial cells was observed with OV-TL 3 and more heterogeneous staining with MOv18. In 12 and nine patients, respectively, a difference in staining intensity for OV-TL 3 and MOv18 was observed between various tumour samples from the same patient.

CONCLUSION

MOv18 has greater therapeutic potential because of its restricted reactivity with normal tissues and especially, in contrast to OV-TL 3, its lack of reactivity with haematopoietic cells.

Tumor uptake of intravenously administered radiolabeled antibodies in ovarian carcinoma patients in relation to antigen expression and other tumor characteristics

To study factors that possibly influence the heterogeneous tumor uptake of radiolabeled antibodies, tissues from 34 ovarian-carcinoma patients were obtained 2 to 8 days after i.v. injection with radiolabeled murine OV-TL3 or chimeric MOv18 (cMOv18). The tumor uptake and the ratio of tumor to normal tissue (T/NT) were studied in relation to the histopathological classification, prior treatment, site of tumor, time interval, antigen expression, volume percentage of (malignant) epithelium in the tumor tissue, and the size of the tumor. The results of immunoscintigraphy were also included. In addition, autoradiography using storage phosphor technology was performed on tissue sections from patients injected with iodine-labeled cMOv18. Tumor uptake varied largely, not only between patients, but also between tumor deposits within the same patient. Uptake of OV-TL3 F(ab')2 was higher than of cMOv18 F(ab')2, but the T/NT ratios were similar. The antibody uptake was positively correlated with the pattern of antigen expression and inversely correlated with the time interval between injection and surgery. No correlation was observed with any of the other factors studied. The visibility with immunoscintigraphy was related to the size of the detected lesion, but not to the other factors studied. Autoradiography showed that antibodies preferentially localized in areas with cancer cells, which were immunohistochemically positive for MOv18. In areas with weak antigen expression, autoradiography revealed less activity. The antigen expression by the tumor is an important factor for estimation of the tumor uptake of radiolabeled antibodies.

Minor human antibody response to a mouse and chimeric monoclonal antibody after a single i.v. infusion in ovarian carcinoma patients: a comparison of five assays

The human anti-(mouse Ig) antibody (HAMA) response was measured in serum of 52 patients suspected of having ovarian carcinoma who had received an i.v. injection of either the murine monoclonal antibody (mAb) OV-TL 3 F(ab')2 (n = 28, 1 mg) or the chimeric mouse/human mAb MOv18 (cMOv18; n = 24, 3 mg). Serum samples were taken before injection and 2-3 and 6-14 weeks after administration. A double-antigen or bridging assay was developed to detect responses against both murine as well as chimeric antibodies. In addition, an indirect enzyme-linked immunosorbent assay (ELISA) as well as three commercially available assays were used to study antibody response against the murine antibody OV-TL 3. With both the double-antigen (bridging) assay and the indirect ELISA 1 of the 28 patients (4%) injected with murine OV-TL 3 F(ab')2 showed a HAMA reaction 6 weeks after injection, which was demonstrated to be a mixed anti-isotypic and anti-idiotypic response. None of the 24 patients injected with the chimeric MOv18 showed an anti-chimeric antibody response. The various commercially available assays demonstrated conflicting results. The double-antigen- or bridging assay is a reliable method to detect anti-murine and anti-chimeric antibodies. The assay can be easily adapted for use with human antibodies. The immunogenicity of OV-TL 3 F(ab')2 and cMOv18 in patients is low, making both antibodies candidates for immunotherapy.