There has been interest in the potential of synthetic compounds to modify immune responses by imitation of cytokine action. Direct administration of interleukin 2 (IL-2) in conjunction with adoptive transfer of lymphokine activated killer cells has been used in the treatment of cancer, but there are toxic effects resulting from the high doses of IL-2 required. We have developed a new synthetic compound, ammonium tri-chloro(dioxoethylene-O,O'-)tellurate (AS-101), which has immunomodulating properties and minimal toxicity. The effects of AS-101 on the activation and function of immunocompetent cells have been assessed. We have found that AS-101 induces proliferation and IL-2 production by human lymphocytes in vitro, and enhances the production of IL-2 and colony-stimulating factor by mouse spleen cells. Splenocytes of BALB/c mice injected with AS-101 increased production of IL-2 and CSF in vitro in the presence of mitogen. Mononuclear cells of normal donors acquired responsiveness to recombinant IL-2 and bound monoclonal antibody to IL-2 receptor after incubation with AS-101. Splenocytes of mice treated in vivo with AS-101 expressed high levels of IL-2 receptor. The stimulation of lymphocytes by AS-101 apparently involves an increase in intracellular free calcium. AS-101 administered systemically to mice mediated antitumour effects which could be attributable to its immunomodulatory properties. In addition, AS-101 could directly enhance the ratio of OKT4 to OKT8-positive cells in cultured mononuclear cells from AIDS (acquired immune deficiency syndrome) patients. These results indicate that AS-101 is potentially useful in the treatment of clinical conditions involving immunosuppression.

The role of IL-10 in experimental sepsis is controversial. The nontoxic immunomodulator, ammonium trichloro(dioxoethylene-o,o′)tellurate (AS101) has been previously shown to inhibit IL-10 expression at the transcriptional level. In this study, we show that in mice subjected to cecal ligation and puncture (CLP), treatment with AS101 12 h after, but not before, CLP significantly increased survival of septic mice. This was associated with a significant decrease in serum IL-10 and in IL-10 secretion by peritoneal macrophages 24–48 h after CLP. At that time, the ability of these cells to secrete TNF-α and IL-1β was restored in AS101-treated mice. The increased survival of AS101-treated mice was due to the inhibition of IL-10, since cotreatment with murine rIL-10 abolished the protective activity of AS101. AS101 increased class II Ag expression on peritoneal macrophages, severely depressed in control mice, while it did not affect the expression of class I Ags. This was accompanied by a significant elevation in the level of IFN-γ secreted by splenocytes. Moreover, AS101 ameliorated bacterial clearance in the peritoneum and blood and decreased severe multiple organ damage, as indicated by clinical chemistry. Furthermore, myeloperoxidase levels in the liver and lung of AS101-treated mice, an indirect means of determining the recruitment of neutrophils, were significantly decreased. We suggest that nontoxic agents such as AS101, with the capacity to inhibit IL-10 and stimulate macrophage functions, may have clinical potential in the treatment of sepsis, provided they are administered during the phase of sepsis characterized by immune suppression.

ABSTRACT

Isolation and characterization of a distinct cytokine pattern in patients with advanced cancer treated with AS101 may contribute to the development of intervention strategies using this compound.

The immunomodulator AS I0 I has been demonstrated to exhibit radioprotective and chemoprotective effects in mice. Following phase-I studies, preliminary resulk from phase-ll clinical trials on non-small-cell-lung-cancer patients showed a reduction in the severity of alopecia in patients treated with A S l O l in combination with chemotherapy. To further substantiate these findings, the present study was extended to include 58 patienk treated either with the optimal dose of 3 mg/rn2 AS I0 I combined with carboplatin and VP-16, or with chemotherapy alone. As compared with patienk treated with chemotherapy alone, there was a significant decrease in the level of alopecia in patients receiving the combined therapy. The newly developed rat model was used to elucidate the protective mechanism involved in this effect. We show that significant prevention of chemotherapy-induced alopecia is obtained in rats treated with Ara-C combined with AS 10 I, administered i.p. or S. C. or applied topically to the dorsal skin. We show that this protection by AS I0 I is mediated by macrophage-derived factors induced by AS I0 I. Protection by AS I0 I can be ascribed, at least in part, to IL-I, since treatment of rats with IL-IRA largely abrogated the protective effect of AS I0 I. Moreover, we demonstrate that in humans there is an inverse correlation between the grade of alopecia and the increase in IL-la. In addition, protection by A S l O l could be related to PGE2 secretion, since injection of indomethacin before treatment with AS I0 I and Ara-C partly abrogated the protective effect of AS 10 I. To assess the ability of AS 10 I to protect against chemotherapy-induced alopecia, phase-ll clinical trials have been initiated with cancer patienk suffering from various malignancies.o 1996 Wiley-Liss, Inc.The psychological impact of chemotherapy-induced alopecia represents one of the more devastating side effects of cancer chemotherapy and, in some instances, leads patients to refuse potentially curative chemotherapy (Hood, 1986). Although this complication has been known for many decades, little progress has been made in its prevention or treatment (Wood, 1985), in part because of lack of a suitable, reproducible experimental model. A new model has now been developed in which chemotherapy induces total alopecia in 8-dayold rats (Hussein et al., 1990). This model enables the investigation of agents that might protect against chemotherapyinduced alopecia, and the elucidation of their mechanism of action.The immunomodulator ASlOl [ammonium trichloro (dioxyethylene-0,O') tellurate] has been shown by us to exhibit radioprotective properties when injected into mice prior to sub-lethal and lethal doses of irradiation (Kalechman et al., 1990). In addition, AS101 was found to protect mice from hemopoietic damage caused by sub-lethal doses of various chemotherapeutic drugs, and to increase the rate of survival of mice treated with lethal doses of these agents. These include cyclophosphamide (Kalechman et al., 1991a), 5-FU (Kalechman et al., 1991b)...

One of the most common side effects of treatment with cyclosporin A (CsA) is hypertrichosis. This study shows that calcineurin activity is associated with hair keratinocyte differentiation in vivo, affecting nuclear factor of activated T cells (NFAT1) activity in these cells. Treatment of nude or C57BL/6 depilated normal mice with CsA inhibited the expression of keratinocyte terminal differentiation markers associated with catagen, along with the inhibition of calcineurin and NFAT1 nuclear translocation. This was associated with induction of hair growth in nude mice and retardation of spontaneous catagen induction in depilated normal mice. Furthermore, calcineurin inhibition blocked the expression of p21waf/cip1 and p27kip1, which are usually induced with differentiation. This was also associated with an increase in interleukin-1α expression (nude mice), a decrease in transforming growth factor-β (nude and normal mice), and no change in keratinocyte growth factor expression in the skin. Retardation of catagen in CsA-treated mice was accompanied by significant alterations in apoptosis-related gene product expression in hair follicle keratinocytes. The ratio of the anti-apoptotic Bcl-2 to proapoptotic Bax expression increased, and expression of p53 and interleukin-1β converting enzyme activity decreased. These data provide the first evidence that calcineurin is functionally active in follicular keratinocytes and that inhibition of the calcineurin-NFAT1 pathway in these cells in vivo by CsA enhances hair growth.

Interaction between the integrin VLA-4 on acute myelogenous leukemia (AML) cells with stromal fibronectin is a decisive factor in chemotherapeutic resistance. In this study, we provide a rationale for a drug repositioning strategy to blunt integrin activation in AML cells and restore their sensitivity to chemotherapy. Specifically, we demonstrate that the nontoxic tellurium compound AS101, currently being evaluated in clinical trials, can abrogate the acquired resistance of AML. Mechanistic investigations revealed that AS101 caused redox inactivation of adjacent thiols in the exofacial domain of VLA-4 after its ligation to stromal fibronectin. This effect triggered cytoskeletal conformational changes that decreased PI3K/Akt/Bcl2 signaling, an obligatory step in chemosensitization by AS101. In a mouse xenograft of AML derived from patient leukemic cells with high VLA-4 expression and activity, we demonstrated that AS101 abrogated drug resistance and prolonged survival in mice receiving chemotherapy. Decreased integrin activity was confirmed on AML cells in vivo. The chemosensitizing activity of AS101 persisted in hosts with defective adaptive and innate immunity, consistent with evidence that integrin deactivation was not mediated by heightening immune attack. Our findings provide a mechanistic rationale to reposition the experimental clinical agent, AS101, to degrade VLA-4-mediated chemoresistance and improve clinical responses in patients with AML. Cancer Res; 74(11); 3092-103. Ó2014 AACR.

AS101 has significant bone marrow (BM)-sparing effects and prevents hair loss in chemotherapy-treated patients, with minimal overall toxicity. These effects are probably due to increased production of IL-1 alpha, IL-6, and granulocyte-macrophage (GM)-CSF.