Potential stem cell marker CD44 is constitutively expressed in permanent cell lines of head and neck cancer.

BACKGROUND: Despite significant advances in the use of diagnosis and therapy to treat head and neck squamous cell carcinoma (HNSCC), the prognosis has improved only marginally in the last decades. Thus, there is an enormous need for better understanding of tumor biology and reversely novel immunotherapeutic approaches. It is becoming increasingly obvious that stem cells play an important role in tumor development and progression. The identity of these cells and the underlying cellular and molecular mechanisms are mostly unknown in HNSCC to date. MATERIALS AND METHODS: Solid HNSCC tumors, as well as permanent HNSCC cell lines, were analyzed by flow cytometry concerning the expression of different putative stem cell marker proteins. RESULTS: Distinct populations of CD44 expressing potential stem cells could be identified in solid tumors of HNSCC patients with strong individual deviations. Surprisingly, the potential stem cell marker CD44 was found to be constitutively expressed on the surface of all the permanent HNSCC cell lines analyzed. CONCLUSION: CD44+ 'tumor stem cells' may play a key role in the establishment of permanent HNSCC cell lines, selecting especially robust cell entities that might drive the progression and metastasis of HNSCC. Individual analysis of 'tumor stem cell' markers will be an important tool for innovative therapies and for determining the prognosis of patients with HNSCC.

Head and neck cancer triggers increased IL-6 production of CD34+ stem cells from human cord blood.

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) are infiltrated by various kinds of immune cells, which show massively impaired immune functions. The influence of HNSCC on CD34 + progenitor cells from human cord blood was analyzed. MATERIALS AND METHODS: CD34+ cells were isolated from human cord blood by 'magnetic bead separation' using magnetically labelled antibodies. Immunofluorescent staining of CD34+ cells in solid HNSCC was carried out. Cytokine levels of IL-6, IL-8, and IL-10 were analyzed with flow cytometry using the BD CBA Human Soluble Protein Flex Set system (Becton Dickinson). RESULTS: We demonstrated that HNSCC triggered CD34+ cells to produce increased levels of the tumor-promoting cytokine IL-6 and thus they participate in the development of the microenvironment of head and neck cancer. CONCLUSION: HNSCC modulates the cytokine secretion profile of tumor infiltrating cells to escape from efficient immune responses und to trigger its own malignant progression.

Physiological levels of 5 alpha-dihydrotestosterone depress wound immune function and impair wound healing following trauma-hemorrhage.

HYPOTHESIS: Studies indicate that a depressed wound immune function contributes to an increased rate of wound complications and impaired wound healing following trauma-hemorrhage (T-H). Androgen, ie, 5 alpha-dihydrotestosterone, is responsible for producing the depressed systemic cell-mediated immune responses following T-H in males. The aim of the present study was to determine whether depletion of 5 alpha-dihydrotestosterone in males before T-H has any salutary effects on wound immune cell function and wound healing in male mice following T-H. DESIGN: Mice were castrated or sham castrated 14 days before midline laparotomy (ie, tissue trauma) and subcutaneous polyvinyl sponge implantation, followed by hemorrhage (mean +/- SEM blood pressure, 35 +/- 5 mm Hg for 90 minutes and resuscitation) or sham operation. At 24 hours thereafter, wound immune cells from the sponges were harvested and cultured with lipopolysaccharide A. Release of interleukin 1 beta (IL-1 beta) and IL-6 (in picograms per milliliter) was determined in the supernatants by enzyme-linked immunosorbent assay. In addition, IL-6 was assessed at the wound site by immunohistochemistry. Ten days after T-H, wound-breaking strength was measured. RESULTS: Precastration prevented the significantly suppressed capacity of wound immune cells to release IL-1 beta and IL-6. In addition, precastration normalized the elevated IL-6 expression at the wound site in the T-H mice. Moreover, wound-breaking strength was improved in castrated mice 10 days after T-H. CONCLUSIONS: Male sex steroids appear to be responsible for wound immune cell dysfunction following trauma and severe blood loss. Because decreasing androgen levels resulted in improved wound healing, our results suggest that the use of androgen receptor-blocking agents, eg, flutamide, following T-H might represent a novel adjunct for decreasing the rate of wound complications under those conditions.

L-arginine: a unique amino acid for improving depressed wound immune function following hemorrhage.

OBJECTIVE: To determine whether L-arginine has any salutary effects on wound immune cell function following trauma-hemorrhage. BACKGROUND: Depressed wound immune function contributes to an increased incidence of wound infections following hemorrhage. Although administration of L-arginine has been shown to restore depressed cell-mediated immune responses following hemorrhage potentially by maintaining organ blood flow, it remains unknown whether L-arginine has any salutary effects on the depressed local immune response at the wound site. METHODS: Male mice were subjected to a midline laparotomy and polyvinyl sponges were implanted subcutaneously in the abdominal wound prior to hemorrhage (35 +/- 5 mm Hg for 90 min and resuscitation) or sham operation. During resuscitation mice received 300 mg/kg body weight L-arginine or saline (vehicle). Sponges were harvested 24 h thereafter, wound fluid collected and wound immune cells cultured for 24 h in the presence of LPS. Pro- (IL-1 beta, IL-6) and anti-inflammatory (IL-10) cytokines were determined in the supernatants and the wound fluid. In addition, wounds were stained for IL-6 immunohistochemically. In a separate set of animals, skin and muscle blood flow was determined by microspheres. RESULTS: The capacity of wound immune cells to release IL-1 beta and IL-6 in vitro was significantly depressed in hemorrhaged mice receiving vehicle. Administration of L-arginine, however, improved wound immune cell function. In contrast, in vivo the increased IL-6 release at the wound site was decreased in L-arginine-treated mice following hemorrhage. Moreover, IL-10 levels were significantly increased in the wound fluid in hemorrhaged animals receiving L-arginine compared to vehicle-treated mice. In addition, the depressed skin and muscle blood flow after hemorrhage was restored by L-arginine. CONCLUSIONS: Thus, L-arginine might improve local wound cell function by decreasing the inflammatory response at the wound site. Since L-arginine protected wound immune cell function this amino acid might represent a novel and useful adjunct to fluid resuscitation for decreasing wound complications following hemorrhage.