Anti-insulin-like growth factor-I activity of a novel polysulphonated distamycin A derivative in human lung cancer cell lines

Modulation of response to radiation of human lung cancer cells following insulin-like growth factor 1 receptor inactivation

Targeted disruption of the insulin-like growth factor 1 receptor (IGF-1R) restricts proliferation of tumor cells and enhances their in vitro radiosensitivity. However, there is little information regarding the effect of IGF-1R expression and function on the lung cancer response to radiotherapy. In this study, we evaluated the cell surface expression of IGF-1R and the antitumoral effect of IGF-1R blockade in combination with irradiation in 6 non-small cell lung cancer (NSCLC) cell lines. All cell lines showed specific IGF-1 binding with an affinity ranging from 0.95x10(-9) to 2.3x10(-9) M, which was evaluated by competitive binding assay. The amount of binding sites ranged from 118 to 377 fmol/mg protein. In one cell line (U1810), the combined treatment led to synergistic cell death and was associated with an accumulation of cells in the G2 phase. IGF-1R activation was able to obstruct serum starvation/radiation-induced cell death in U1810 cell line. Additive interactions were found for four cell lines (A549, H157, H23 and H125) whereas only subadditive effects were observed in U1752 cell line. Our results indicate that the IGF-1R is present on NSCLC cells and thereby its involvement in the modulation of radiosensitivity in lung cancer cells.

Antiangiogenic strategies, compounds, and early clinical results in breast cancer

Angiogenesis is a multi-step process leading to the formation of new blood vessels from pre-existing vasculature and it is necessary for primary tumor growth, invasiveness and development of metastasis. Experimental and clinical data demonstrated that breast cancer is an angiogenesis-dependent disease and that the vascular endothelial growth factor (VEGF) family plays a key role it being a highly expressed and selective endothelial cell growth factor. Preclinical studies have shown that the angiogenic switch occurs early in the multistage process of breast cancer development. Targeting the molecular pathways involved in tumor progression by biologically-designed treatments is a new therapeutic paradigm aimed to reach cancer growth control. A number of possible therapeutic targets for antiangiogenic agents have been identified. Here we discuss the therapeutic approach based on inhibition of angiogenesis in the context of breast cancer with a focus on the early clinical studies on antiangiogenic agents in advanced disease.

Small cell lung cancer: from molecular biology to novel therapeutics

Small cell lung cancer (SCLC) is an aggressive tumor which metastasizes early. Patients with this disease have a poor prognosis even with immediate treatment. Because of the aggressive nature of this disease, all aspects of this tumor are studied extensively. This review will provide an update of the biology of SCLC at both the molecular and cellular levels. Cellular pathways and their relationship to cellular function will also be discussed. Treatment of both primary limited- and extensive-stage diseases as well as recurrent disease will be discussed including chemotherapy, thoracic radiotherapy, and surgery. The role of novel therapeutics being investigated will also be addressed.

Synthetic DNA minor groove-binding drugs

In this review, both cationic and neutral synthetic ligands that bind in the minor groove of DNA are discussed. Certain bis-distamycins and related lexitropsins show activities against human immunodeficiency virus (HIV)-1 and HIV-2 at low nanomolar concentrations. DAPI binds strongly to AT-containing polymers and is located in the minor groove of DNA. DAPI intercalates in DNA sequences that do not contain at least three consecutive AT bp. Berenil can also exhibit intercalative, as well as minor groove binding, properties depending on sequence. Furan-containing analogues of berenil play an important role in their activities against Pneumocystis carinii and Cryptosporidium parvuam infections in vivo. Pt(II)-berenil conjugates show a good activity profile against HL60 and U-937 human leukemic cells. Pt-pentamidine shows higher antiproliferative activity against small cell lung, non-small cell lung, and melanoma cancer cell lines compared with many other tumor cell lines. trans-Butenamidine shows good anti-P. carinii activity in rats. Pentamidine is used against P. carinii pneumonia in individuals infected with HIV who are at high risk from this infection. A comparison of the cytotoxic potencies of adozelesin, bizelesin, carzelesin, cisplatin, and doxorubicin indicates that adozelesin is a potent analog of CC-1065. Naturally occurring pyrrolo[2,1-c][l,4]benzodiazepines such as anthramycin have a 2- to 3-bp sequence specificity, but a synthetic PBD dimer spans 6 bp, actively recognizing a central 5'-GATC sequence. The crosslinking efficiency of PBD dimers is much greater than that of other major groove crosslinkers, such as cisplatin, melphalan, etc. Neothramycin is used clinically for the treatment of superficial carcinoma of the bladder.

Responsiveness to hormone, growth factor and drug treatment of a human breast cancer cell line: comparison between early and late cultures

Growth rate, morphology, and responsiveness to mitogenic stimuli and pharmacological treatments were evaluated in early and late cell passages derived from the same clone of the widely used MCF-7 human breast adenocarcinoma cell line. Our results indicate dissimilarities between early (E) and late (L) passages for some of the parameters analyzed. The cells that underwent many subcultivations grew faster than the others; both appeared homogeneous in size and shape. The E cells, subcultured for almost 1 yr, displayed higher sensitivity to the mitogenic action of both estradiol, according to the level of estrogen receptor, and insulin-like growth factor-I than did the L cells, kept in culture for more than 10 yr. Cell responsiveness to two drugs, a novel steroid antiestrogen and a polysulfonated distamycin A derivative, was more pronounced in the early cultures only at the longer time of exposure to the higher concentration of the estrogen antagonist. In addition, a drug-induced inhibition of insulin-like growth factor-I binding to its receptor was shown in both E and L cells, the latter being less sensitive than the former when exposed to the antiestrogen. Finally, MCF-7 E and L cells showed similar behavior when drug-induced apoptosis was tested.