merocyanine-dye and Breast-Neoplasms

A pulsed (17 nanoseconds) Nd:YAG laser (1064 nm) was used to inject impermeable dyes (propidium iodide andiodide and merocyanine 540) and a plasmid (pEGFP-N1) encoding green fluorescent protein (GFP) into human breast adenocarcinoma cells (MCF-7). The cell membrane integrity and viability were fully preserved in this laser-assisted transfer.

Topics: Adenocarcinoma; Breast Neoplasms; Cell Membrane Permeability; Cell Survival; Drug Delivery Systems; Green Fluorescent Proteins; Humans; Lasers; Luminescent Proteins; Microinjections; Plasmids; Propidium; Pyrimidinones; Transfection; Transformation, Genetic; Tumor Cells, Cultured

High-dose chemotherapy combined with autologous stem cell support has improved response rates in high-risk and metastatic breast cancer, but has failed to improve long-term survival. Breast cancer has a tendency to metastasize to the bone marrow, and live tumor cells are known to circulate in the peripheral blood of breast cancer patients. Sensitive immunohistochemical, culture-based, and reverse transcriptase polymerase chain reaction (RT-PCR)-based methods have shown that about 50% of histologically normal stem cell grafts from breast cancer patients are contaminated with occult tumor cells, which may cause or contribute to tumor recurrences. Merocyanine 540 (MC540)-mediated photodynamic therapy (PDT) inactivates a wide range of leukemia and lymphoma cells and is well tolerated by normal hematopoietic stem and progenitor cells. Unfortunately, most solid tumor cells (including breast cancer cells) are only moderately sensitive or refractory to MC540-PDT. We report here that if MC540-PDT is followed by a 1-h incubation with the alkyl-lysophospholipid, Edelfosine (ET-18-OCH(3)), the depletion of murine and human breast cancer cells is greatly enhanced whereas the recovery of normal hematopoietic stem and progenitor cells is only minimally degraded. When used under conditions that reduce CD34-positive human bone marrow cells only 5.1-fold, and murine and human granulocyte/macrophage progenitors 6.8- and 3-fold, respectively, combination purging with MC540-PDT and Edelfosine depletes murine (Mm5MT) and human (MDA-MB-435S) breast cancer cells >17,000- and >125,000-fold, respectively. These data suggest that combination purging with MC540-PDT and Edelfosine may offer a simple, safe and effective method for the ex vivo purging of autologous stem cell grafts from breast cancer patients.

Topics: Animals; Antigens, CD; Antigens, CD34; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Cryopreservation; Female; Hematopoietic Stem Cells; Humans; Mice; Phospholipid Ethers; Photochemotherapy; Pyrimidinones; Radiation-Sensitizing Agents; Tumor Cells, Cultured; Tumor Stem Cell Assay

In previous studies we have reported that preactivated merocyanine 540 (pMC540) and its chemically synthesized isolates merocil and merodantoin mediate their preferential cytotoxicity towards certain types of malignant cells including human breast cancer cells in vitro and in vivo. The mechanism of cytotoxic action appears to be, in part, via initial interaction with topoisomerase II leading to apoptosis. To further build upon these findings we now show that pMC540 and merodantoin disrupt mitochondrial morphology and function in intact MCF-7 human breast cancer cells as seen by their causing the release of rhodamine 123 from prestained cells, a rapid reduction in ATP levels, inhibition of succinate dehydrogenase activity and oxygen consumption. These data suggest that mitochondria may also be an important target for the cytotoxic action of pMC540 and merodantoin mediated through disruption of the energy balance.

Topics: Adenosine Triphosphate; Antineoplastic Agents; Breast Neoplasms; Cell Survival; Ethylenethiourea; Fluorescent Dyes; Humans; Microscopy, Electron; Microscopy, Fluorescence; Mitochondria; Oxygen Consumption; Pyrimidinones; Rhodamine 123; Rhodamines; Succinate Dehydrogenase; Tumor Cells, Cultured

Preactivation is a novel photochemical method for the production of chemotherapeutic compounds that exert their biologic effects independent of light. The compounds that are produced, preactivated merocyanine 540 (pMC540) and merodantoin, are cytotoxic to cultured human breast cancer cells but are only minimally cytotoxic toward normal cells. Their effects against breast cancer have not been studied in vivo.. Estrogen-stimulated human MCF-7 breast adenocarcinoma cells were grown as solid tumors in athymic carrier mice. Animals bearing defined sizes of subcutaneously transplanted solid breast tumors received injections of pMC540 (250 mg/kg) with or without concurrent treatment with tamoxifen. Growth inhibitory effects of merodantoin (N,N'-dibutyl-2-thio-4,5-imidazolidion) on the breast tumor growth were determined.. Direct injection of established tumors with eight doses of pMC540 (250 mg/kg) administered on alternate days resulted in significant tumor regression (P = 0.002). In three of seven animals, palpable tumors could not be detected after this treatment (16 days). Treatment through intramuscular injections (20 doses) with pMC540 (250 mg/kg) also caused a significant suppression of tumor area (P = 0.004; P = 0.0882; P = 0.0903) and a marginally significant suppression of tumor weight and volume, respectively. Combined treatment with tamoxifen and pMC540 (100 mg/kg) caused a 67% suppression of breast tumor growth. Treatment with 20 doses of merodantoin (75 mg/kg) suppressed the growth of breast tumors by 98%.. To the authors' knowledge, these results show for the first time that photochemically generated novel compounds in pMC540 alone and in combination with tamoxifen are effective in suppressing in vivo growth of xenografted human MCF-7 breast tumors.

Topics: Animals; Breast Neoplasms; Cell Division; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Ethylenethiourea; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasms, Hormone-Dependent; Pyrimidinones; Tamoxifen; Transplantation, Heterologous

Topics: Bone Marrow; Bone Marrow Transplantation; Breast Neoplasms; Cell Survival; Colony-Forming Units Assay; Combined Modality Therapy; Doxorubicin; Female; Humans; Laser Therapy; Photochemotherapy; Pyrimidinones; Radiation-Sensitizing Agents; Transplantation, Autologous; Tumor Cells, Cultured