A new approach in the immunotherapy of carcinoma of the colon and rectum

Antitumor immunity enhancement through Newcastle viral oncolysate in mice model: A promising method to treat tumors

A Newcastle disease virus (NDV) oncolysate has been established as a unique and effective immune-stimulatory root for tumor treatment. Thus, the aim of the current study was to investigate the effects of intratumoral administration of NDV oncolysate on immune response and tumor regression of C57BL/6 mouse model of human papillomavirus (HPV) related transplanted with TC-1 syngeneic cancer cells. To further investigate the mechanism underlying the antitumor response, cytolytic and lymphocyte proliferation responses in splenocytes were measured using lactate dehydrogenase (LDH) release and MTT assays, respectively. In this regard, levels of IL-10, IFN-γ, and IL-4 were measured using ELISA after re-stimulation. The immune responses efficacy was evaluated by in vivo tumor regression assay. The results showed that immunization with the different titers of NDV lysate significantly reduced tumor volume in comparison with a combination of virus lysate and tumor cell lysate. Also, virus lysate could significantly enhance cytotoxic T lymphocyte production and lymphocyte proliferation rates versus tumor cell lysate. Also, our major findings are that the peritumorally injection of NDV oncolysate effectively induces antitumor immune responses through increased levels of IL-4, IFN-γ, and reduction of IL-10. These results indicate that this treatment is a specific, active immune mechanism stimulator, and may prove to be a useful therapeutic for a treatment against cervical cancers and merits further investigation.

Immune responses of DBA/2 mice bearing melanoma tumors: cell-mediated immune responses after challenge with vaccinia virus

Cell-mediated immune responses in DBA/2 mice bearing melanoma tumors (TB-mice) were measured and compared to similar responses in mice without tumors (C-mice). Splenic lymphocytes from TB-mice had a reduced capacity to respond to both B and T-cell mitogens, but TB-mice responded to infection with vaccinia virus by developing a virus-specific cytotoxic T-cell response equal to that measured with splenic effectors prepared from virus-infected C-mice. NK-cell activity, as measured by the in vitro lysis of YAC-1 targets by splenic effectors, was significantly depressed in TB-mice but, after infection of the animals with vaccinia virus, was restored to levels equal to that measured with splenic effectors prepared from C-mice. Doses of vaccinia virus, strain WR which elicited vaccinia-virus-specific cytotoxic T cells or stimulated NK-cell activity, failed to elicit or stimulate cytotoxic effectors specific for S91-melanoma tumor cells.

Defining the needs for adjuvant therapy of rectal and colonic cancer

Current trials concerned with the adjuvant therapy for large bowel cancer demonstrate for the first time that improvements in survival through the use of adjuvant therapy may be possible in rectal cancer. Similar results in well-designed studies are not evident for colonic cancer. These trials deserve confirmation. In addition, they demonstrate the biologic difference in the behavior of colonic and rectal cancer despite similar requirements in defining curative surgical resection. A comparison of trials unique to individual institutions suggests that the lenient criteria for patient selection and the use of historical control groups make the data from these studies impossible to interpret for extrapolation to wide clinical use. The variations in the survival rates of historical groups, both among different studies and within the same study, suggest that the design of adjuvant therapy programs without concurrent surgically treated control groups will predictably produce a study of limited value, but one that is guaranteed to generate continued controversy. Uniformity of language, staging, and method of reporting is invaluable if individual trials of adjuvant therapy are to become comparable. The development and widespread use of an agreed-upon staging method is an important step in the preparation for further adjuvant trials. The definition of additional prognostic factors (beyond mural penetration and nodal involvement) in rectal cancer and stratification for these additional factors in the design of studies concerning adjuvant therapy in rectal cancer seems to be a target of importance for future studies of adjuvant therapy. Focusing attention on which patients with rectal cancer actually derived a benefit from treatment may assist in the development of a pattern in which surgical goals and radiation goals can achieve better definition in clinical use.

The immune response to carcinoma of the colon in a rat model: a temporal study

Carcinoma of the colon was induced in rats by treatment with 1, 2-dimethylhydrazine (DMH). Macroscopic tumours were observed from eight weeks after commencing DMH injections and rapidly increased in mass to cause death of the animals between 20 and 27 weeks later. Tumour immunity was assessed by the gross parameters of body, spleen and mesenteric lymph node weight and by in vitro tests of lymphocyte antitumour cytotoxicity and leucocyte migration inhibition by tumour and normal colon homogenates. Immune responses were recorded in control (saline treated) and in tumour (DMH treated) rats. Body weight of the tumour rats paralleled that of control animals until tumours were well advanced. At this time tumour animal body weight was significantly less than that of control animals. Spleen weight and in vitro lymphocyte antitumour cytotoxicity were significantly greater in tumour than in control rats and were so found soon after macroscopic tumours were observed. Mesenteric lymph node weight and leucocyte migration inhibition did not change until late in tumour development, but at this time there was an immune response in tumour animals. The study showed that carcinoma of the colon induced in rats was associated with an antitumour immune response and that this change occurred soon after macroscopic tumours were present. In spite of this the animals died of their neoplasms.