Interferon-alpha 2b modulation of doxorubicin sensitivity in a multidrug resistant cell line.

We evaluated the effect of interferon-alpha2b as a chemosensitiser on HCT-15 cell line in treatment with doxorubicin. Chemosensitivity was determined by [3H]-thymidine incorporation and tetrazolium assays. The levels of expression of P-glycoprotein, Bcl-2 oncoprotein and HLA-ABC complex, and cell cycle/apoptosis analysis were determined by flow cytometry. Dox 50 ng/ml - IFN alpha 2b 500 IU/ml treatment inhibited cell proliferation (47.2 +/- 1.4%, p < 0.0001; MTT assay: 40.6 +/- 1.2%, p < 0.0001) and augmented the expression of P-170, Bcl-2 and HLA-ABC, while it didn't exert apoptosis, producing a slight G2/M arrest. A concentration of IFN-alpha2b, that by itself is not cytotoxic, can potentiate the efficacy of the anticancer drug. This effect is not due to a down-modulation of P-170. The absence of apoptosis and augmented levels of Bcl-2 expression suggests that this could be one of the mechanisms of drug resistance exerted by these cells.

Tumor necrosis factor-alfa production by monocytes from lung and colorectal cancer patients.

Tumour necrosis factor-alpha (TNF-alpha) is a monocyte (MO)-derived cytokine that plays an essential role in the immunological system. In the present study our aim was to evaluate the levels of TNF-alpha secreted by MO from cancer patients. Blood MO were obtained from 10 lung cancer patients (LCP), 10 colorectal cancer patients (CCP) and 10 healthy donors (HD). TNF-alpha levels in MO culture supernatants spontaneously (sp) secreted or after stimulation with LPS treatment were evaluated using a commercial ELISA kit (sensibility: 10-1000 pg/ml). Mean values, expressed as pg/ml were: LCP: sp= 452.6+/-107.2, LPS= 589.5+/-126.7); CCP: sp= 84.1+/-25.0, LPS= 437.3+/-93.2; HD: sp= 74.2+/-21.5, LPS= 573.5+/-87.1. We concluded that MO from LCP secrete high levels of TNF-alpha spontaneously (p< 0.003 versus HD) and it was also observed an absence of response to LPS treatment in the 33% of the cases in these patients.

In vitro secretion of cytokines and prostaglandin-E2 by monocytes from lung cancer patients.

Monocytes (MO) from cancer patients present functional abnormalities, such as an altered secretion of soluble factors. In the present study, our aim was to evaluate the levels of interleukin-1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha) and prostaglandin-E2 (PGE2) secreted in vitro by MO from lung cancer patients (LCP), spontaneously or after stimulation with lipopolysaccharide (LPS). Results showed that cytokine secretion was higher for MO from LCP than for MO from healthy controls, while in the 25% of the patients analysed, an absence of response to LPS treatment was found.

Regulation of HLA-DR antigen in monocytes from colorectal cancer patients by in vitro treatment with human recombinant interferon-gamma.

During the immune response, a great number of cytokines that modulate the function of mononuclear phagocytes are produced. Since interferons are one of the most important cytokines, the aim of this study was to evaluate the expression of HLA-DR antigen after an 18-h culture with human recombinant interferon-gamma (hrIFN-gamma) on freshly isolated peripheral blood monocytes from 16 colorectal cancer patients and 16 healthy donors, using an indirect immunofluorescence method. The results obtained showed that there was a decreased percentage of HLA-DR+ monocytes in the colorectal cancer patents (51 +/- 3%, p <0.01) compared with the healthy donors (77 +/- 2%). Treatment for 18 h with hrIFN-gamma increased the percentages of monocytes expressing HLA-DR: 71 +/- 3% for the cancer patients and 84 +/- 2% for the healthy donors (p <0.01 and <0.001, respectively). Our results demonstrate that after in vitro treatment with hrIFN-gamma, functionally altered monocytes from colorectal cancer patients can reach major histocompatibility complex II antigen expression values similar to those of healthy donors, thus improving the host's cellular immune response against the tumor.

Effect of culture supernatants from two cancer cell lines on healthy donors' monocytes.

BACKGROUND: it is well known that culture cells secrete to their medium different factors that can alter their own as well as other cells' metabolism and functions. In the present study we evaluated the effect of culture supernatants originated from two cancer cell lines, Calu-1 (lung epidermoid carcinoma) and A-427 (lung adenocarcinoma) on peripheral blood monocytes (MO) from 20 healthy donors (HD). METHODS AND RESULTS: MO were incubated with supernatants or with medium only (controls) during 2 or 18 hours. There were determined the expression of HLA-DR antigen by indirect immunofluorescence technique, the formation of reactive oxygen intermediates (NBT reduction capacity) and the phagocytic capacity (Candida albicans- anti Candida albicans system). These determinations were made also in MO from 16 patients with advanced lung cancer (LCP). Percentages of expression (media +/- SE) were: HLA-DR (+) MO: Calu-1 = 30 +/- 2; A-427 = 31 +/- 2; LCP = 52 +/- 3 (p < 0.0001 vs HD: 77 +/- 1%) NBT (+)MO: Calu-1 = 47 +/- 1; A-427 = 49 +/- 1; LCP = 56 +/- 2 (p < 0.01 vs HD: 45 +/- 2%), Phagocytic MO: Calu-1 = 38 +/- 3; A-427 = 39 +/- 2; LCP = 32 +/- 3 (p < 0.0001 vs HD: 50 +/- 1%). CONCLUSIONS: we conclude that this in vitro model reproduced characteristics found in MO from lung cancer patients, since culture supernatants induced in normal MO phenotypic and functional characteristics also found in MO from patients analyzed.

Cisplatin containing chemotherapy influences HLA-DR expression on monocytes from cancer patients.

The effect of cisplatin-containing chemotherapy regimen was evaluated on the expression of HLA-DR antigen in peripheral blood monocytes from patients with lung (LCP) and colorectal (CCP) cancer. Chemotherapeutic schedules employed in patients were etoposide and cisplatin for LCP and 5-fluorouracil and cisplatin for CCP. The results obtained showed a diminished percentage of monocytes expressing HLA-DR antigen in LCP (52.4 +/- 2.6, p < 0.004) and CCP (50.1 +/- 2.1, p < 0.001) respectively versus healthy donors (71.0 +/- 1.1%), and that their values increased during chemotherapy, raising them up to control level after the second cycle of treatment, independently of the course of the cancer growth. We conclude that both modalities of treatment allowed an increase of monocytes expressing HLA-DR antigen, suggesting that this effect may be due to cisplatin action.