tretinoin and mofarotene

Effective chemotherapy for pancreatic cancer is urgently needed. The anti-proliferative activity of a new retinoid, mofarotene (RO40-8757), was compared with that of other retinoids, such as all trans-retinoic acid, 13-cis retinoic acid and 9-cis retinoic acid, on 9 pancreatic cancer cell lines in relation to the effects on various cell cycle-regulating factors. After treatment with each retinoid, anti-proliferative effect was determined by the MTT method and expression of cell cycle-regulating factors, such as cyclins (D1, E and A), cyclin-dependent kinases (2 and 4), cyclin-dependent kinase inhibitors (p21 and p27) and retinoblastoma protein, was analyzed by Western blotting. Mofarotene showed half-maximal inhibition of cell proliferation at concentrations between 0.14 x 10(-6) and 3.8 x 10(-6) mol/l with little cytotoxicity. In contrast, the other retinoids did not inhibit the growth of all cell lines by over 50% compared to controls. A marked increase in the fraction of cells in G1 phase of the cell cycle was observed after mofarotene treatment; this was associated with marked up-regulation of p21/p27 and a shift of retinoblastoma protein into the hypophosphorylated form. In conclusion, mofarotene inhibits the growth of pancreatic cancer cells by inducing G1-phase cell cycle-inhibitory factors (p21, p27 and hypophosphorylated form of Rb protein) and is considered to be a useful agent for pancreatic cancer treatment.

Topics: Alitretinoin; Antineoplastic Agents; Blotting, Western; CDC2-CDC28 Kinases; Cell Cycle; Cell Cycle Proteins; Cell Division; Cyclin-Dependent Kinase 2; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinase Inhibitor p27; Cyclin-Dependent Kinases; Cyclins; Dose-Response Relationship, Drug; Humans; Isotretinoin; Microtubule-Associated Proteins; Morpholines; Pancreatic Neoplasms; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Retinoblastoma Protein; Retinoids; Time Factors; Tretinoin; Tumor Cells, Cultured; Tumor Suppressor Proteins; Up-Regulation

Natural and synthetic retinoids have proved to be effective in the treatment and prevention of various human cancers. In the present study, we investigated the effect of retinoids on Epstein-Barr virus (EBV)-infected lymphoblastoid cell lines (LCLs), since these cells closely resemble those that give rise to EBV-related lymphoproliferative disorders in the immunosuppressed host. All six compounds tested inhibited LCL proliferation with no significant direct cytotoxicity, but 9-cis-retinoic acid (RA), 13-cis-RA, and all-trans-RA (ATRA) were markedly more efficacious than Ro40-8757, Ro13-6298, and etretinate. The antiproliferative action of the three most effective compounds was confirmed in a large panel of LCLs, thus appearing as a generalized phenomenon in these cells. LCL growth was irreversibly inhibited even after 2 days of treatment at drug concentrations corresponding to therapeutically achievable plasma levels. Retinoid-treated cells showed a marked downregulation of CD71 and a decreased S-phase compartment with a parallel accumulation in Gzero/ G1 phases. These cell cycle perturbations were associated with the upregulation of p27 Kip1, a nuclear protein that controls entrance and progression through the cell cycle by inhibiting several cyclin/cyclin-dependent kinase complexes. Unlike what is observed in other systems, the antiproliferative effect exerted by retinoids on LCLs was not due to the acquisition of a terminally differentiated status. In fact, retinoid-induced modifications of cell morphology, phenotype (downregulation of CD19, HLA-DR, and s-Ig, and increased expression of CD38 and c-Ig), and IgM production were late events, highly heterogeneous, and often slightly relevant, being therefore only partially indicative of a drug-related differentiative process. Moreover, EBV-encoded EBV nuclear antigen-2 and latent membrane protein-1 proteins were inconstantly downregulated by retinoids, indicating that their growth-inhibitory effect is not mediated by a direct modulation of viral latent antigen expression. The strong antiproliferative activity exerted by retinoids in our experimental model indicates that these compounds may represent a useful tool in the medical management of EBV-related lymphoproliferative disorders of immunosuppressed patients.

Topics: Antigens, CD; Antigens, Differentiation, B-Lymphocyte; Antigens, Surface; B-Lymphocytes; Benzoates; Cell Cycle; Cell Cycle Proteins; Cell Division; Cell Line, Transformed; Cell Transformation, Viral; Cyclin-Dependent Kinase Inhibitor p27; Etretinate; Gene Expression Regulation; Growth Inhibitors; Herpesvirus 4, Human; Humans; Isotretinoin; Microtubule-Associated Proteins; Morpholines; Receptors, Transferrin; Retinoids; Tretinoin; Tumor Suppressor Proteins

Apolipoprotein D (apoD) is a human plasma protein, belonging to the lipocalin superfamily, that is produced by a specific subtype of highly differentiated breast carcinomas and that is strongly up-regulated by retinoic acid (RA) in breast cancer cells. In this work, we have examined the molecular mechanisms mediating the induction of apoD gene expression by retinoids in T-47D human breast cancer cells. Northern blot analysis revealed that Ro40-6055, a synthetic retinoid that selectively binds and activates the retinoic acid receptor RARalpha, induced the accumulation of apoD mRNA in breast cancer cells in a time- and dose-dependent manner. The time course analysis demonstrated that apoD mRNA was induced 14-fold over control cells after 48 h of incubation with 10(-8) M Ro40-6055. As little as 10(-11) M of this retinoid induced apoD mRNA 5-fold over the control, whereas incubation with 10(-7) M Ro40-6055 induced maximally 15-fold over control cells. RARalpha-selective antagonists counteracted the inductive effects of all-trans-RA, 9-cis-RA, and Ro40-6055 on the expression of apoD, when present at the same concentration as the retinoid agonists. By contrast, RARbeta-, RARgamma-, and RXR-selective retinoids did not affect apoD gene expression. The retinoid agonist Ro40-6055 had an antiproliferative effect on T-47D cells, with maximal growth inhibition of approximately 60% obtained after 7 days of incubation with 10(-7) M. This antiproliferative effect could be counteracted by a 100-fold excess of the antagonist Ro41-5253. Treatment of the cells with retinoids that do not bind the nuclear retinoic acid receptors did not affect apoD expression, despite the fact that they did have a strong antiproliferative effect on T-47D cells. On the basis of these results, a role for RARalpha on apoD gene expression induction by retinoids in breast cancer cells is proposed.

Topics: Antineoplastic Agents; Apolipoproteins; Apolipoproteins D; Benzoates; Breast Neoplasms; Cell Division; Chromans; Female; Humans; Morpholines; Receptors, Retinoic Acid; Retinoids; RNA, Messenger; Signal Transduction; Tetrahydronaphthalenes; Tretinoin

A novel arotinoid with a morpholine structure in the polar end group Ro 40-8757 (4-[2-[p-[(E)-2(5,6,7,8-Tetrahydro-5,5,8,8-tetramethyl-2- naphthyl)propenyl]phenoxy]ethyl]-morpholine) was tested for its anti-proliferative activity against nine human cancer cell lines in vitro. The lines included two estrogen receptor positive breast cancer lines (MCF-7 and ZR-75-1), two estrogen receptor negative breast cancer lines (MDA-MB-231 and BT-20), one cervix carcinoma line (KB-3-1), two lung adenocarcinoma lines (A549 and HLC-1), one large cell lung cancer line (LXFL 529) and two colorectal lines (CXF 243 and CXF 280). Proliferation of all the lines, except the two lung adenocarcinoma lines, was inhibited by lower concentrations of Ro 40-8757 than those of all-trans retinoic acid (RA) or 13-cis RA giving the same level of inhibition. The degree of inhibition of RO 40-8757 was concentration and time dependent. The arotinoid was not cytotoxic and morphological signs by differentiation were not evident in cultures treated with Ro 40-8757 for up to 2 weeks. Because this compound is active on cells such as KB-3-1 that are not inhibited by all-trans RA and because it does not bind to nuclear retinoic acid receptors, it may represent a novel class of anti-proliferative agents.

Topics: Adenocarcinoma; Antineoplastic Agents; Breast Neoplasms; Carcinoma, Non-Small-Cell Lung; Cell Cycle; Cell Division; Cell Survival; Colorectal Neoplasms; Drug Screening Assays, Antitumor; Humans; Kinetics; Lung Neoplasms; Morpholines; Neoplasms; Receptors, Estrogen; Retinoids; Tetrazolium Salts; Thiazoles; Tretinoin; Tumor Cells, Cultured

A novel arotinoid, 4-((2-(p-[(E)-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl- 2-naphthyl)propenyl]phenoxy))ethyl))-morpholine, was tested in rats bearing established chemically induced mammary tumors. At a dose of 0.35 mmol/kg/day of 4-((2-(p-[(E)-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2- naphthyl)propenyl]phenoxy)ethyl))-morpholine, decreased tumor growth was seen after 2 weeks. By weeks 4 and 5, tumor burdens were decreased to 10-30% of initial values and 50-70% of the animals became free of palpable tumors. Stabilization of tumor size through 15 weeks of treatment was seen in rats given 0.23 mmol/kg/day of the arotinoid. The predominate adverse effects of this compound were dose-dependent weight loss during the first 1-3 weeks, attributed to poor palatability of the food admix as well as flaking of the skin and alopecia at later times. Bone toxicity, a characteristic side effect of retinoids in rodents, was rare with this arotinoid, mainly confined to young rats treated for more than 12 weeks with high doses. In a comparative study, neither all-trans-retinoic acid nor 13-cis-retinoic acid had significant antitumor effects at doses that were tolerated by the animals. When all-trans-retinoic acid was administered at 0.08 mmol/kg/day, tumor reduction was seen during weeks 4-6, but treatment was terminated after week 6 due to severe skeletal toxicity and general deterioration in all the animals. Such marked toxicity was not evident with the arotinoid at doses having high antitumor activity. The high efficacy and relatively low toxicity of 4-((2-(p-[(E)-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2- naphthyl)propenyl]phenoxy)ethyl))-morpholine suggest that it may be a promising new anticancer agent.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Antineoplastic Agents; Disease Models, Animal; Eating; Female; Mammary Neoplasms, Experimental; Morpholines; Rats; Rats, Sprague-Dawley; Retinoids; Tretinoin