Narendra P. Singh

The objective of the present study was to investigate how oxidative status influences the effectiveness of cytotoxicity of artemisinin towards cancer cells. It is hypothesized that antioxidants would reduce, whereas pro-oxidants would enhance, cytotoxicity. Molt-4 human leukemia cells were incubated with vitamins C, E, D3, dexamethasone, or hydrogen peroxide alone or in combination with dihydroartemisinin (DHA). Concentrations of these compounds studied were similar to those achievable by oral administration. Viable cell counts were performed before (0 h) and at, 24 and 48 h after treatment. Vitamin C, vitamin D3, dexamethasone, and H2O2 caused significant Molt-4 cell death. Vitamin E caused an increase in Molt-4 cell growth. Vitamin C and vitamin D3 significantly interacted with DHA at the 48-h time point and with H2O2 at both 24-h and 48-h time points. Cellular oxidative status could alter the potency of artemisinin in killing cancer cells.

The standard methods of chemotherapy in cancer treatment are expensive and pose serious health effects. The present study investigates an alternative chemotherapy by testing the combined treatment of two drugs on leukemia cells: dihydroartemisinin (DHA) and sodium salicylate (SS). Cells were divided into 4 treatment groups: a control, treatment with DHA-only, treatment with SS-only, and treatment with both DHA and SS. Cells were counted immediately before the addition of any reagents (0-h count), and at 24, 48, and 72 h after treatment. At low concentrations, the combination of DHA and SS significantly reduced cancer cell proliferation, although no synergistic interaction between the two drugs was found. Even without a clear synergistic interaction, the combination of DHA and SS provides a safe and affordable form of cancer treatment.

Derivatives of artemisinin, a compound extracted from the wormwood Artemisia annua L, have potent anticancer properties. The anticancer mechanisms of artemisinin derivatives have not been fully-elucidated. We hypothesize that the cytotoxicity of these compounds is due to the free radicals formed by interaction of their endoperoxide moiety with intracellular iron in cancer cells. The effects of N-tert-butyl-alpha-phenylnitrone (PBN), a spin-trap free radical scavenger, and deferoxamine (DX), an iron chelating agent, on the in vitro cytotoxicity of dihyroartemisinin (DHA) toward Molt-4 human T-lymphoblastoid leukemia cells were investigated in the present study. Dihydroartemisinin effectively killed Molt-4 cells in vitro. Its cytotoxicity was significantly attenuated by PBN and DX. Based on the data of our present and previous studies, we conclude that one anticancer mechanism of dihydroartemisinin is the formation of toxic-free radicals via an iron-mediated process.

Artemisinin has been shown to be an effective antimalarial and anticancer compound. Dimers of artemisinin have been synthesized and shown to be potent antimalarials compared with monomers. In the present study, we investigated the effect of two artemisinin dimers (dimer-alcohol and dimer-hydrazone) on rat mammary adenocarcinoma cells (MTLn3) in vitro and in vivo compared with that of the artemisinin monomer dihydroartemisinin (DHA). We found that the dimers are considerably more potent than DHA in killing MTLn3 cells in vitro and suppressing the growth of MTLn3 breast tumors in vivo.

Although dihydroartemisinin (DHA) and other artemisinin derivatives have selective toxicity towards cancer cells, Artemisia annua (A. annua) extracts containing artemisinin have not been evaluated for their anticancer potential. Our main goal was to assess the anticancer effect of ethanolic leaf extracts of A. annua from Brazilian and Chinese origins (with DHA as a comparison) on normal and cancer cells. Leukocytes and leukemia (Molt-4) cells were counted at 0, 24, 48, and 72 hr after treatment with extracts having artemisinin concentrations of 0, 3.48, 6.96, and 13.92 µg/mL. Also, we assessed the antioxidant capacity of these extracts using the oxygen radical absorbance capacity (ORAC) test. Both extracts had high antioxidant capacity and toxicity towards Molt-4 cells. DHA was significantly more potent (p < 0.05) in killing Molt-4 cells than Brazilian extract at 48 and 72 hr and Chinese extract at 72 hr. In Molt-4 cells, LD₅₀ values for Brazilian and Chinese extracts were comparable at all time points and not significantly different from DHA at 24 hr. In leukocytes, DHA, Chinese extract, and Brazilian extract had LD₅₀ values of 760.42, 13.79, and 28.23 µg/mL of artemisinin, respectively, indicating a better safety index for the Brazilian extract compared to that of the Chinese extract at 24 hr. However, at 48 and 72 hr, the toxicity in leukocytes for any of the treatment groups was not significantly different. These experiments suggest that these extracts may have potential application in cancer treatment.

Artemisinin is a compound isolated from the wormwood Artemisia annua L. It reacts with iron and forms cytotoxic free radicals. It is selectively more toxic to cancer than normal cells because cancer cells contain significantly more intracellular free iron. Previously, we found that covalently tagging artemisinin to transferrin enhanced the selectivity and toxicity of artemisinin toward cancer cells in vitro. In the present research, artemisinin-transferrin conjugate was tested in a rat breast cancer model. Breast tumors were induced in rats by subcutaneous implantation of rat MTLn3 breast cancer cells. Once tumors were formed, daily intravenous injections of artemisinin-transferrin conjugate were administered. The conjugate significantly retarded the growth rate of breast tumors in the rat. No significant side effect was observed in the rats during treatment. Artemisinin-transferrin conjugate could be developed into a potent therapeutic agent for cancer in humans.

Introduction: This report describes the case of a male patient with pituitary macroadenoma treated with the artemisinin analog artemether. Patient and Methods: A 75 year-old male patient presented with vision, hearing, and locomotion-related problems. Artemether was administered orally to the patient over a period of 12 months. Results: Although the tumor remained consistent in size, CT scan shows a reduction in its density, and clinically, the related symptoms and signs resolved significantly as therapy progressed. Discussion: Overall, the artemether treatment was beneficial in improving the patient's quality of life. Artemether and other artemisinin analogs offer promise for cancer therapy.

Butyric acid is a short chain fatty acid produced by large bowel bacterial flora. It serves as an antiinflammatory agent and nutrient for normal colon cells. Butyric acid has also been shown to induce apoptosis in colon and many other cancer cells. Artemisinin is a compound extracted from the wormwood Artemisia annua L. It has been shown to selectively kill cancer cells in vitro and to be effective in treating animal and human cancer. We and others have found that the artemisinin analog, dihydroartemisinin (DHA), kills cancer cells by apoptosis. In the present study, the efficacy of a combined treatment of DHA and butyric acid at low doses in killing cancer cells was investigated. Molt-4 cells (a human lymphoblastoid leukemia cell line) and freshly isolated human lymphocytes, cultured in complete RPMI-1640 medium, were first incubated with 12 microM of human holotransferrin at 37 degrees C in a humid atmosphere of 5% CO2 for one hour to enhance the iron concentration in the cells. Cells from each cell type were then divided into 20 flasks. These flasks were grouped into four sets of five cultures each. Zero, 5, 10 or 20 microM of DHA was added, respectively, to these sets and the cells were incubated at 37 degrees C for one hour. Zero, 1, 5, 10, or 20 mM of sodium butyrate was then added to the five cultures of each set, respectively. Thus, the treatments involved a combination of 4 doses of DHA and 5 doses of sodium butyrate. The cells were counted immediately before the addition of DHA, and at 24 and 48 hours after the addition of sodium butyrate. DHA alone at the 24-hour time-point and 20 microM concentration significantly reduced the number of Molt-4 cells in the culture by approximately 40% (p < 0.001, compared to non-treated control), whereas it did not significantly affect the number of normal human lymphocytes. Similarly, 1 mM sodium butyrate alone at 24 hours reduced the number of Molt-4 cells by approximately 32% (p < 0.001, compared to non-treated control), without significantly affecting normal human lymphocytes. The combination of 20 microM DHA and 1 mM sodium butyrate killed all Molt-4 cells at the 24-hour time-point and did not significantly affect lymphocytes. DHA in combination with butyric acid acts synergistically at low doses. The combination may provide a less toxic, inexpensive and effective cancer chemotherapy.

Artemisinin is a chemical compound extracted from the wormwood plant, Artemisia annua L. It has been shown to selectively kill cancer cells in vitro and retard the growth of implanted fibrosarcoma tumors in rats. In the present research, we investigated its mechanism of cytotoxicity to cancer cells. Molt-4 cells, in complete RPMI-1640 medium, were first incubated with 12 microM of human holotransferrin at 37 degrees C in a humid atmosphere of 5% CO2 for one hour. This enhanced the iron supply to the cells. The cells were then pelleted and transferred to a complete RPMI-1640 containing 200 microM of an analog dihydroartemisinin (DHA) and incubation was started (0 h). In addition, some culture samples were treated with holotransferrin alone and some (controls) were assayed without neither holotransferrin nor DHA treatment. Cells were counted and DNA diffusion assay was used to evaluate apoptosis and necrosis in each sample at 0 h and at 1, 2, 4 and 8 h of incubation. DHA treatment significantly decreased cell counts and increased the proportion of apoptosis in cancer cells compared to controls (chi2=4.5, df=1, p<0.035). Addition of holotransferrin significantly further decreased cell counts (chi2=4.5, df=1, p<0.035) and increased apoptosis (chi2=4.5, df=1, p<0.035). No necrotic cells were observed. This rapid induction of apoptosis in cancer cells after treatment with DHA indicates that artemisinin and its analogs may be inexpensive and effective cancer agents.