Kashtan H

In vitro and in vivo effects of photodynamic therapy on murine malignant melanoma

AbstractBackground: The role of photodynamic therapy (PDT) in the treatment of malignant melanoma is not well defined, nor is it known whether the dark melanoma cells absorb the light used in PDT. Methods:In vitro studies: 2×105 B16 murine melanoma cells were incubated with aluminum phthalocyanine (AlpcS4, 2.5 mg/kg) and were then subjected to photoradiation (50, 100 or 200 J/cm2). Viability was then assessed.In vivo studies: Histology: C57/B1 mice received 2×105 B16 cells subcutaneously and were randomized into study (PDT) and three control groups. AlpcS4 2.5 mg/kg was injected intraperitoneally and the mice were exposed to light (100 J/cm2). After 24 hours they were sacrificed and underwent autopsies. Survival: 40 mice were randomized into PDT (40 J/cm2) and control groups and were monitored for 50 days. Tumor growth: 40 mice were randomized into one control and three treatment groups (PDT on day 3, 6, or 12 after injection with B16 cells), and were monitored for 50 days. Temperature: Tumor temperatures before and at the end of PDT were recorded. Results:In vitro studies: PDT caused a decrease in cell viability to 15.5±0.7%, 11.5±2.1%, and 1.5±0.7% (at 50, 100, and 200 J/cm2, respectively;P<.001). A significant reduction in thymidine incorporation was noted at all energy levels.In vivo studies: Histology: PDT caused massive tumor necrosis. Survival: PDT prolonged the survival of mice (41±13.4 days) compared to controls (15.8±3.8 days,P<.001). Tumor growth: 31 days after injection with B16 cells, the tumor size was 2.6±0.3 cm in the control group and 1.6±0.2, 0.9±0.3, and 1.0±0.4 cm in the PDT groups (days 3, 6 and 12, respectively;P<.01). Temperature: PDT increased skin temperature to 42.8°C±1.3°C, 45.3°C±3.5°C, and 51.7°C±2.7°C at 40, 60, and 100 J/cm2, respectively (P<.01). Conclusions: Photodynamic therapy was found to have significant effects in experimental melanoma in mice. The role of PDT in human melanoma remains to be studied.

Antitumor effects of recombinant interleukin-6 expressed in eukaryotic cells.

In the present study we evaluate the antitumor efficacy of a glycosylated molecule of interleukin-6 (IL-6), which was cloned and expressed in Chinese hamster ovary cells. When tested with two syngeneic murine tumors, the MC38 adenocarcinoma and the MCA106 fibrosarcoma, recombinant IL-6 (rIL-6) significantly reduced the number of day-3 established MC38 lung metastases, but had no effect on MCA106 lung metastases. A similar effect of rIL-6 was seen on day-3 MC38 liver metastases. The antitumor activity mediated by rIL-6 was achieved at doses of the cytokine ranging from 6 µg to 150 µg/day. There was no correlation between the responsiveness to rIL-6 of these two tumors and their susceptibility, in vitro, to a direct cytostatic effect of the cytokine or the increase in the expression of major histocompatibility complex (MHC) antigens after exposure to rIL-6. However, a correlation was seen between the antitumor response to rIL-6 and the initial number of tumor cells expressing MHC antigens. The possible role of MHC antigens expressed on tumor cells, the generation of MHC-restricted cytotoxic cells and the responsiveness to IL-6 are discussed.

Immunoguided Lymph Node Dissection in Colorectal Cancer: A New Challenge?

AbstractKnowledge of lymphatic involvement in patients with colorectal cancer is important in surgery and in the postoperative decision-making process. Fifty-eight patients with recurrent colorectal cancer underwent operation with the RIGS® (Radioimmunoguided Surgery) technology. Preoperatively, patients were injected with 1 mg monoclonal antibody (MoAb) CC49 (anti-TAG-72-tumor-associated glycoprotein) labeled with 2 mCi of iodine 125. Traditional surgical exploration was followed by survey with a gamma-detecting probe. Localization of MoAb on tumor was noted in 54/58 patients (93%). Traditional exploration identified 117 suspected tumor sites. With RIGS, 177 suspected tumor sites were detected. In 17 of the 58 patients (27.5%), at least one occult tumor site identified by RIGS was confirmed by pathology with hematoxylin & eosin (H & E) staining. This finding resulted in 16 major changes in surgical plan. RIGS performance varied between lymphatic and non-lymphatic tissue, with a positive predictive value (PPV) of 95.6% and negative predictive value (NPV) of 90% in non-lymphoid tissue compared to PPV of 40% and NPV of 100% in lymphoid tissue. In patients with tumors that localize, no RIGS activity in lymph nodes signifies no tumor, while decisions based on RIGS activity in lymph nodes requires H & E confirmation. Using this guideline, additional information acquired by RIGS can help the surgeon in making an informed decision during surgery and in planning postoperative therapy.

Continuous Intravenous Octreotide Treatment for Acute Experimental Pancreatitis

Background: The efficacy of octreotide, the synthetic analogue of the hormone somatostatin, for the treatment of acute pancreatitis is controversial. Octreotide has been commonly administered in subcutaneous bolus injections; however, continuous intravenous infusion may be advantageous for acute conditions. Methods: Acute experimental pancreatitis was induced in rats by intraparenchymal injections of 1 ml 10% sodium taurocholate, and octreotide (1 µg/kg/h, dissolved in physiological solution, intravenously was started 4 h later and continuously infused for 48 h. Physiological solution infusions, in identical volumes, were used in the controls. The following parameters were examined: mortality; macroscopic and histological damage; hematocrit; plasma pH; acid-base balance; serum glucose; calcium, and amylase. Results: Octreotide treatment had a striking effect on mortality: 8.3 versus 91.6% in the treatment and control groups, respectively (p < 0.001). Octreotide also ameliorated pancreatic edema and intestinal dilatation, and had significant beneficial effects on histopathological damage and the biochemical alterations which are associated with acute pancreatitis. Conclusions: Continuous intravenous octreotide infusion is a potentially efficacious therapeutic method for acute pancreatitis.

Identification of lymph node metastases in recurrent colorectal cancer.

Lymph node metastases are an important prognostic prediction factor in patients with recurrent colorectal cancer, particularly those with liver metastasis. Fifty-six patients with recurrent colorectal cancer were operated by us using the RIGS (radioimmunoguided surgery) technology. Patients were injected with 1 mg monoclonal antibody (MoAb) CC49 labeled with 2 mCi 125I. In surgery, traditional exploration was followed by survey with a gamma-detecting probe. Sixty of 151 patients enrolled in the Neo2-14 Phase III study for recurrent colorectal cancer were diagnosed with liver metastases based on preoperative CT. In 17/56 patients (30%), RIGS identified at least one tumor site confirmed by pathology (H&E). This resulted in 16 major changes in surgical plan. RIGS performance varied between lymphatic and non-lymphatic tissue, with positive predictive value (PPV) of 100% and negative predictive value (NPV) of 94% for non-lymphoid tissue, compared to PPV of 46.5% and NPV of 100% for the lymphoid tissue. Thirty-five out of 60 patients were considered resectable after traditional evaluation. RIGS identified occult tumor in 10 of these patients (28.5%). 7/10 occult patients expired (70%), while only 7/25 of the non-occult patients expired (28%) (P = 0.046). In localizing patients, no RIGS activity in lymph nodes signifies no tumor, while H&E confirmation is needed for decisions based on RIGS activity in the lymph nodes. RIGS provides important staging information, identifying patients for whom surgery may be done with curative intent.

Photodynamic therapy for Bowen's disease and squamous cell carcinoma of the skin

BACKGROUND Photodynamic therapy involves the activation by visible light of a previously administered photosensitizing agent in order to cause tumor necrosis. Skin tumors can be treated with topical photosensitizers and thus avoiding systemic side effects. In this study we evaluate the immediate and long-term effects of photodynamic therapy (PDT), using aminolevulinic acid (ALA) as a photosensitizer and a non-laser light source, on Bowens disease (intra-epithelial squamous cell carcinoma) and on frank squamous cell carcinoma (SCC) of the skin. METHODS ALA in cream form (20%) was topically applied on biopsy-proven Bowens disease or SCC of the skin. The lesions were covered with occlusive and light-shielding dressing. Sixteen hours later, they were submitted to a 10-min light session using Versa-Light™, a non-laser light source (spectral output of 580-720nm and 1250-1600nm, 100J/cm(2)). The initial evaluation was done 21 days post-treatment and every 3m thereafter. Patients that did not respond to treatment after two to three sessions were referred to surgery. RESULTS Forty Bowens disease lesions (24 patients) and 43 SCC lesions (18 patients) underwent treatment. Median follow-up was 21±8m. No patient had any remarkable side effects. Thirty-four Bowens disease (85%) lesions completely responded as did 32 SCC lesions (74%). CONCLUSIONS Our findings showed that PDT is highly effective in treating Bowens disease and SCC lesions and can be used as a first treatment modality in so far as its use does not preclude the subsequent surgery recommended for the small percentage of failures.

Photodynamic therapy of colorectal cancer using a new light source: from in vitro studies to a patient treatment

Photodynamic therapy (PDT) is a relatively new alternative modality for palliation of rectal cancer. We evaluate a new light source for PDT. In vitro PDT: CT26 murine colon carcinoma cells were incubated with aluminum phthalocyanine (AlPcS4) for 48 hours, subjected to photoradiation using Versa-Light and viability was assessed. There was a significant decrease in viability of treated cells as compared with controls. In vivo PDT: Balb/C mice were injected either subcutaneously or intrarectally with CT26 cancer cells. IP AlPcS4 2.5 mg/kg was injected when tumors were visible. After 24 hours mice were subjected to photoradiation. Massive tumor necrosis in response to PDT was observed. PDT also prolonged survival of the treated mice. Patient treatment: A 70 year old woman with recurrent local rectal carcinoma received IV Photofrin II 2 mg/kg. After 48 and 96 hours she was subjected to direct photoradiation. After the first light session there was complete macroscopic disappearance of the tumor. Biopsies up to 10 weeks after the treatment showed no cancer cells in the treated area. We believe that Versa-Light is a good light source for PDT. It was effective in both in-vitro and animal studies. It can also be safely used for clinical PDT.