Expansion of mucin-reactive T-helper lymphocytes from patients with colorectal cancer

Gamma probes and their use in tumor detection in colorectal cancer

The purpose of this article is to summarize the role of gamma probes in intraoperative tumor detection in patients with colorectal cancer (CRC), as well as provide basic information about the physical and practical characteristics of the gamma probes, and the radiopharmaceuticals used in gamma probe tumor detection. In a significant portion of these studies, radiolabeled monoclonal antibodies (Mabs), particularly 125I labeled B72.3 Mab that binds to the TAG-72 antigen, have been used to target tumor. Studies have reported that intraoperative gamma probe radioimmunodetection helps surgeons to localize primary tumor, clearly delineate its resection margins and provide immediate intraoperative staging. Studies also have emphasized the value of intraoperative gamma probe radioimmunodetection in defining the extent of tumor recurrence and finding sub-clinical occult tumors which would assure the surgeons that they have completely removed the tumor burden. However, intraoperative gamma probe radioimmunodetection has not been widely adapted among surgeons because of some constraints associated with this technique. The main difficulty with this technique is the long period of waiting time between Mab injection and surgery. The technique is also laborious and costly. In recent years, Fluorine-18-2-fluoro-2-deoxy-D-glucose (18F-FDG) use in gamma probe tumor detection surgery has renewed interest among surgeons. Preliminary studies during surgery have demonstrated that use of FDG in gamma probe tumor detection during surgery is feasible and useful.

Disabled infectious single-cycle herpes simplex virus as an oncolytic vector for immunotherapy of colorectal cancer

New modalities of treatment for colorectal cancer are required to support and improve those currently available. One such approach is immunotherapy by transfer of immunostimulatory genes to tumor cells. Here, we report the use of a herpes simplex virus (HSV) vector that is capable of a single round of infection (disabled infectious single-cycle [DISC]-HSV) as a gene transfer vehicle for colorectal cancer. This vector has potential advantages over other vectors for cancer immunotherapy in that it lyses infected tumor cells. Infection with DISC-HSV inhibited tumor cell growth both in vitro and in vivo. In addition, DISC-HSV-mediated cell killing occurs by both apoptotic and necrotic mechanisms. A range of colorectal tumor cell lines could be rapidly transduced with DISC-HSV/lacZ (14-90% in 4 hr). Both tumor prevention and tumor therapy protocols showed clear antitumor effects with DISC-HSV/mGM-CSF. In the prophylactic approach, an infected/irradiated whole cell vaccine protected up to 80% of mice from rechallenge. In addition, intratumoral injection of established tumors with DISC-HSV/GM-CSF caused rejection in 40% of mice and generated some protection from subsequent rechallenge. In both cases, however, it is clear that a dominant therapeutic effect of the DISC-HSV vector derives from its oncolytic properties, irrespective of the transduced gene. As a prelude to taking these studies forward to human clinical trials, we demonstrate that tumor cells could be successfully grown from freshly obtained human colorectal cancer resections (within 1 week of surgery), were transduced with DISC-HSV/hGM-CSF, and secreted the cytokine. This study provides the preclinical basis for trials of immunotherapy of colorectal cancer using DISC-HSV.

Cellular and biological therapies of gastrointestinal tumors: overview of clinical trials

Because of the high relapse rate of resected gastrointestinal malignancies and the modest responses of metastatic disease to currently available therapies, biologic agents that harness host-tumor immunologic interactions have received increased attention. Based on promising preclinical data, current clinical trials in cellular and biologic therapies are evaluating the safety and efficacy of passive immunotherapy with tumor-reactive lymphocytes activated ex vivo and active immunotherapy with peptide, viral vector, and cellular vaccines. This review will describe the background, rationale, and experimental approach of these clinical trials. Although equally promising, antibodies, gene therapies, and antiangiogenic strategies will not be discussed.

Intraoperative radioimmunodetection

The radioimmunoguided surgery (RIGS) system employs a monoclonal antibody (CC49), a radionuclide (Iodine-125), and a hand-held gamma-detecting probe (the Neoprobe model 1000). The prototype cancer studied has been colorectal cancer. The antibody identifies a type of mucin, the by-product of the adenocarcinoma cancer cell. The RIGS system localizes up to 90% of colorectal cancers and finds additional RIGS-positive tissues in >50% of the patients. More than 90% of the RIGS-positive visceral tumors are identified by routine hematoxylin-and-eosin (H&E) light microscopy, but the RIGS-positive lymph nodes are H&E occult tissues in >70% of the cases. Enhanced, more time-consuming methods have been developed to confirm hidden cancer cells in these lymph node tissues. Survival data confirm the importance of RIGS-positive tissues. RIGS-positive tissues remaining at the completion of the surgical procedure portend a much poorer outcome than if the patient is deemed RIGS-negative at the completion of the surgical procedure (i.e., all RIGS-positive tissue was removed at surgery).

Induction of anti-tumour lymphocytes in cancer patients after brief exposure to supernatants from cultures of anti-CD3-stimulated allogeneic lymphocytes

The present study investigated the ability of supernatants collected from cultures of healthy donor-derived peripheral blood mononuclear cells (HD-PBMCs) stimulated with anti-CD3 monoclonal antibody (MAb) (allogeneic CD3 supernatants; ACD3S) to induce, upon brief exposure, tumour-reactive cytotoxic lymphocytes in cancer patients' PBMCs. ACD3S enhanced natural killer (NK) and lymphokine-activated killer (LAK) cell-mediated cytotoxicity. ACD3S contained increased levels of interleukins (IL) 1, 2, 6, 7 and 12, as well as of granulocyte-macrophage colony-stimulating factor (GM-CSF), gamma-interferon (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha). MAbs against these cytokines significantly reduced the ACD3S-induced cytotoxicity. ACD3S-induced cytotoxicity was not inhibited by anti-CD4, CD8 and MHC class I MAbs, but was markedly reduced in the presence of MAb against CD18. In contrast to HD-PBMC, ACD3S derived from cancer patients' lymphocytes exhibited lower levels of the above-mentioned cytokines and exerted reduced biological activity. In conclusion, ACD3S are able to activate, upon short-term incubation, tumour-reactive lymphocytes from cancer patients' PBMCs that lyse a variety of tumour targets, including autologous tumours. ACD3S contain high levels of certain cytokines that positively influence the induction of autologous tumour-reactive lymphocytes. Such supernatants can be collected easily from healthy donors and stored until use in clinical trials for adoptive cellular therapy of cancer. They may also be indicated in the construction of cytokine cocktails that have the ability to induce anti-tumour cytotoxicity.