Decline in peripheral blood NKG2D+CD3+CD56+ NKT cells in metastatic colorectal cancer patients.

OBJECTIVE: Colorectal cancer (CRC) is one of the main causes of cancer deaths in the world. This cancer can be divided into non-metastatic and metastatic CRC stages. CD3+CD56+ NKT cell subsets are a minor T cell subset in peripheral blood and conduct the killing of tumor cells in direct manner. Little is obvious about levels and surface markers of these cells such as NKG2D in different cancers, especially in CRC. METHODS: We included 15 non-metastatic (low-grade), 11 non-metastatic (high-grade), 10 metastatic colorectal cancer patients and 18 healthy controls. The percentages of CD3+CD56+ NKT cells and NKG2D+CD56+ NKT cells from samples were analyzed by flow cytometry in peripheral blood mononuclear cells (PBMCs) of samples. RESULTS: We found that there was a significantly lower number of NKG2D+CD3+CD56+ cells in peripheral blood of patients with metastatic colorectal cancer compared with normal controls (77.53 ± 5.79 % vs 90.74 ± 9.84 %; p<0.01). CONCLUSION: The fact that frequency of NKG2D+CD56+ NKT cells was significantly lower in patients with metastatic colorectal cancer compared to healthy controls strengthens the hypothesis that NKT cells can play a substantial role in the protection against human colorectal cancer, and this opens up avenues for novel studies about elucidating the other aspects of tumor surveillance in CRC progression and immunotherapy (Tab. 2, Fig. 2, Ref. 46).

The decrease in NKG2D+ Natural Killer cells in peripheral blood of patients with metastatic colorectal cancer.

BACKGROUND: Natural killer (NK) cells play important roles in the immune defense against tumors such as colorectal cancer. In humans, NKG2D is an activating immune receptor constitutively expressed in most cytotoxic lymphocytes including NK and CD8+ T cells. In this study, the expression of NKG2D molecule was investigated in peripheral blood NK cells from colorectal cancer patients and compared with healthy subjects. METHODS: We studied 21 non-metastatic (low-grade), 17 non-metastatic (high-grade), 16 metastatic colorectal cancer patients, and 24 healthy controls. Peripheral blood samples were obtained to isolate peripheral blood mononuclear cells (PBMCs) and the percentage of peripheral blood NKG2D+CD3-CD56+ NK cells was analyzed by flow cytometry. The expression of NKG2D at mRNA level was also measured by real-time PCR in both, patients and control subjects. RESULTS: The results showed a significant reduction in the percentage of NKG2D+NK cells as well as NKG2D mRNA expression in peripheral blood of metastatic colon cancer patients. CONCLUSION: This result suggests that decreased expression of activating NKG2D receptor in metastatic colorectal cancer might compromise NK cell function and allow tumor to evade immunity (Tab. 3, Fig. 4, Ref. 33).

Electrokinetic dewatering of Turkish glass sand plant tailings.

In this study, the dewatering of glass sand plant tailings from Mersin, Turkey was investigated using an electrokinetic technique. The particle size (d(80)) of the solid waste material tested was less than 0.020 mm and consisted mainly of silica, orthoclase, alumina, potassium and iron oxides. In current plant practice, Larox high-pressure filters are used to produce a filter cake containing 22-25% moisture. As an alternative, a laboratory-scale dewatering pond using an electrokinetic technique was designed and a final product (cake) containing 34% moisture was obtained after 24h treatment using 14.6 V direct current applied for 40 min. When the treatment continued up to 48 h, a firm-to-hard cake was produced.

Retrovirus-mediated gene transfer of the human multidrug resistance-associated protein into hematopoietic cells protects mice from chemotherapy-induced leukopenia.

Utilization of chemotherapy for the treatment of tumors is mainly limited by its hematological toxicity. Because of the low-level expression of drug resistance genes, transduction of hematopoietic progenitors with multidrug resistance 1 (MDR1) or multidrug resistance-associated protein (MRP) genes should provide protection from chemotherapeutic agent toxicity. Successful transfer of drug resistance genes into hematopoietic cells may allow the administration of higher doses of chemotherapy and, thus, increase regression of chemosensitive tumors. The interest in the use of MRP as an alternative to MDR1 for bone marrow protection lies in its different modulation. This would allow, in the same patient, the use of MDR1 reversal agents to decrease MDR1 tumor resistance without reversing bone marrow (BM) protection of the MRP-transduced hematopoietic cells, since MRP expression is not reversed by these agents. We have constructed MRP-containing retroviral vectors using the phosphoglycerate kinase promoter and generated ecotropic producer cells. Lethally irradiated mice were engrafted with BM cells transduced by coculture with MRP producer cells. Evidence of long-term (9 months) gene transfer was provided by PCR of peripheral blood from MRP-transduced mice. Southern blot analysis confirmed the integrity of the provirus in the MRP-transduced mice. Long-term MRP expression (>5 months) was detected by RT-PCR and fluorescence-activated cell sorting of blood from living mice. High-level expression of MRP in murine hematopoietic cells reduces doxorubicin-induced leukopenia and mortality. Furthermore, we show in vivo selection of MRP-transduced cells following doxorubicin administration, with better and more significant chemoprotection after the second chemotherapy cycle. These data indicate that MRP retroviral gene transfer may be useful for chemoprotection and selection.

Retroviral-mediated transfer of genes encoding interleukin-2 and interleukin-12 into fibroblasts increases host antitumor responsiveness.

The transfer of genes encoding cytokines into tumor cells has emerged as a new strategy to increase in vivo host reactivity to a variety of tumors. Because gene transfer into tumor cells cannot be easily applied in the clinical setting, we have developed an experimental model of gene transfer into fibroblasts and examined the capacity of these engineered cells to elicit an antitumor immune response. Interleukin-12 (IL-12) is a heterodimeric cytokine with pleiotropic activities presenting strong antitumor and antimetastatic effects in murine models. A bicistronic retroviral vector was constructed that contained the cDNAs encoding both chains (p40 and p35) of murine IL-12 separated by an internal ribosomal entry site sequence. Syngeneic cutaneous fibroblasts obtained from newborn mice and transduced to secrete either IL-12 or IL-2 were injected subcutaneously with B16F0 or B16F1 melanoma cells. The time of tumor occurrence and overall survival of mice were significantly prolonged when B16F1 cells were coinjected with cytokine-producing fibroblasts compared with B16F1 alone or B16F1 together with unmanipulated fibroblasts. Systemic effects were seen in the mice injected with either IL-2- or IL-12-secreting fibroblasts, with the highest proliferation capability and interferon-gamma production observed in vitro from splenocytes from recipients of IL-2-secreting fibroblasts. Injection of IL-2-secreting fibroblasts or coinjection of IL-2- and IL-12-producing fibroblasts resulted in a significant increase of survival in the B16F0 model; in some cases, complete disease eradication was observed. These results suggest that cutaneous fibroblasts represent a target of choice for gene transfer and would be useful in the treatment of minimal residual disease in humans.

Clinical significance of total serum IgE determination in screening of Iranian Russian thistle pollen hypersensitive individuals.

Total serum IgE concentrations of normal and Russian thistle (Salsola pestifer) pollen hypersensitive individuals were determined in an Iranian population, using the solid phase radioimmunoassay technique. The mean values were 963.7 and 885.3 ng/ml, respectively, which are much higher than normal values given for non-Iranian populations. In addition, no significant differences were found between observed values (P = 0.1) for normal and allergic individuals. The effect of common parasitic infestation in the Iranian population in causing high serum IgE levels is discussed.