Enhancement of the in vitro cytotoxicity of bouvardin by verapamil alone and combined with hyperthermia in Sarcoma 180 and Ehrlich ascites carcinoma cells.

The cytotoxic effect of bouvardin (BVD) a protein synthesis inhibitor was studied separately and in combination with verapamil (VRP), a vasodilator and hyperthermia (43 degrees C) against Sarcoma 180 (S 180) and Ehrlich ascites carcinoma (EAC) tumour cells in vitro. S 180 cells exhibited natural resistance to hyperthermia and BVD, whereas EAC tumour cells were found to be sensitive. VRP alone did not show cytotoxicity to either tumour cells. A combination of BVD and VRP at an elevated temperature resulted in a greater cell kill in the EAC tumour cell line whereas the natural resistance of S 180 tumour cells to the drug BVD and hyperthermia was circumvented by combination with VRP. Combination of BVD, hyperthermia and VRP resulted in greater cell kill, compared to separate treatment with the single agents. The cytotoxicity was evaluated by comparing the inhibition of incorporation of 3H-thymidine in treated cells to that in untreated cells.

Studies on high-dose chemotherapy of amygdalin in murine P388 lymphocytic leukaemia and P815 mast cell leukaemia.

The anti-tumor activity of amygdalin (NSC 251222), commercially known as Laetrile, was investigated using P388 lymphocytic leukaemia and P815 mast-cell leukaemia in BDF1 mice. Doses varying from 200 mg/kg to 2,000 mg/kg were used following the days 1 and 5 and days 1, 5 and 9 schedules. Despite treatment with high doses of amygdalin there was no prolongation in the life-span of mice bearing either P388 or P815 tumor.

Reversal of natural resistance to bouvardin (NSC 259968) in sarcoma 180 cells in vitro and in vivo by verapamil.

Reversal of natural resistance to bouvardin (NSC 259968) has been attained in vitro and in vivo, by the calcium influx blocker verapamil in sarcoma 180 cells insensitive to bouvardin. Verapamil increased the in vitro lethality of the tumor cells following exposure with cells for 1 and 3 h as a result of the cytotoxic effect of bouvardin. Similar results were observed in vivo when the tumor cells were exposed to verapamil and then treated with bouvardin, showing a significant percent increase in the lifespan to 30% and 45%. This suggested that this calcium channel blocker had interacted with tumor cell membrane to modulate the response of the cells, and make them more amenable to the drug action.

Inhibition of DNA synthesis by lonidamine and hyperthermia in human chronic myeloid leukemia cells.

Lonidamine (LNA) is antitumor agent that lacks the characteristic properties of antiproliferative drugs and has narrow spectrum of antitumour effects. It is also a hyperthermia sensitizer. Hyperthermia affects on various cellular organelles, and the malignant cells are known to be more sensitive to hyperthermia. The present study examines the in vitro effects of LNA (0.01 and 0.02 mM) and hyperthermia (42 degrees C for 1 and 2 hrs) alone and in combination, on 11 human chronic myeloid leukemia cell samples. The inhibition in incorporation of 3H-thymidine was statistically significant (P less than 0.001) in human CML cells when exposed to the combination of LNA (0.01 and 0.02 mM) with hyperthermia (1 and 2 hrs) compared to the single treatment either at the same concentration of LNA at 37 degrees C or hyperthermia alone. Cytotoxicity was evaluated as the inhibition of the incorporation of 3H-thymidine in the cellular nucleic acid. The drug effects were estimated from the changes in rates of incorporation of precursor into DNA and compared with untreated control samples. Cancer cells were incubated in vitro in the presence of radioactive 3H-thymidine and drug.

Some mixed-ligand palladium(II) complexes of 2,2'-bipyridine and amino acids as potential anticancer agents.

Eight new palladium complexes of the formula [Pd(bipy)(AA)]Cl 1 or 2 H2O (where bipy is 2,2'-bipyridine and AA is an anion of glycine, L-alanine, L-leucine, L-proline, L-serine, L-lysine, L-asparagine, or L-glutamine) have been synthesized by reaction of [Pd(bipy)Cl2] with an appropriate mono sodium salt of amino acid in water. These complexes have been characterized by chemical analysis and by visible, infrared, and 1H NMR spectroscopy. The detailed 1H NMR and infrared spectral studies of these complexes ascertain the mode of binding of amino acids to palladium through nitrogen of terminal -NH2 group and oxygen of terminal -COO- group. The molar conductance values of these complexes in water suggest them to be 1:1 electrolytes. These complexes have also shown growth inhibition against L1210 lymphoid leukemic, P388 lymphocytic leukemic, Sarcoma 180, and Ehrlich ascitic tumor cells. Some of these complexes show better 50% inhibitory dose values than cis-diamminedichloroplatinum(II).

Some potential anticancer palladium(II) complexes of 2,2'-bipyridine and amino acids.

Nine new palladium(II) complexes of the formula [Pd(bipy)(AA)]n+ (where bipy is 2,2'-bipyridine, AA is an anion of L-cysteine, L-aspartic acid, L-glutamic acid, L-methionine, L-histidine, L-arginine, L-phenylalanine, L-tyrosine, or L-tryptophan, and n = 0 or 1) have been synthesized by interaction of [Pd(bipy)Cl2] with an appropriate sodium salt of amino acid in water. These palladium(II) complexes have been characterized by chemical analysis and by visible, infrared, and 1H NMR spectroscopy. The modes of binding of amino acids in these palladium complexes have been ascertained by infrared and 1H NMR spectroscopy. The molar conductances of these complexes in water suggest that they are either nonelectrolytes or 1:1 electrolytes. These palladium complexes have shown growth inhibition against L1210 lymphoid leukemic, P388 lymphocytic leukemic, Sarcama 180, and Ehrlich ascites tumor cells. Some of these complexes show I.D.50 values comparable to or lower than cis-diamminedichloroplatinum(II).

Synthesis and spectroscopic studies of potential anticancer [platinum(II)(2,2'-bipyridine)(amino acid)]n+ (n = 1 or 2) complexes.

Six new platinum complexes of the formula [Pt(2,2'-bipyridine)(amino acid)]n+, where n = 1 to 2 and amino acid is an anion of L-histidine, L-lysine, L-asparagine, L-phenylalanine, L-tryptophan, or L-tyrosine, have been prepared by interaction of [Pt(2,2'-bipyridine)Cl2] and an appropriate amino acid (sodium salt) in water or water-methanol mixture. They have been characterized by chemical analyses and spectral methods such as ultraviolet-visible, infrared, and 1H NMR spectroscopy. The 1H NMR studies of these complexes ascertain the modes of binding of amino acids to platinum. The histidine binds to platinum through the nitrogen of a -NH2 group and another nitrogen of heterocyclic ring. All other amino acids bind to platinum through nitrogen of a -NH2 group and oxygen of a -COO- group. The mode of binding of some amino acids to platinum in these complexes has been further confirmed by infrared spectroscopy, and the formulations of these complexes have been supported by conductivity measurements. These six amino acid complexes and also other complexes of glycine, alanine, leucine, serine, cysteine, methionine, and glutamine have shown growth inhibition against P-388 lymphocytic leukemic cells.

Effect of cisplatin-based chemotherapy on emergence of cisplatin resistance, and its correlation with intracellular glutathione levels and accumulation of p53 protein in human ovarian cancer.

Forty-seven ovarian cancer cases in which 20 were previously treated with cisplatin (cisPt) based chemotherapy, were checked for in vitro chemosensitivity using MTT assay. The drugs included in the study were cisPt, adriamycin (ADR), epirubicin (EPR) and etoposide (ETO). The logarithemic concentrations (0.1, 1.0, 10.0 and 100.0 micrograms/ml) of these drugs were used in the MTT assay. The IC50 values for these drugs in the above tumor samples were calculated. The effect of pretreatment with cisPt based chemotherapy on the emergence of drug resistance, expression of p53 protein (detected using immunohistochemical method by employing monoclonal antibody to p53) and intracellular glutathione (GSH) levels was also studied. Our results demonstrated the superiority of EPR in terms of its efficacy as compared to the other drugs used in the study. EPR was effective in both, previously cisPt-exposed and cisPt-unexposed ovarian cancer cases indicating its importance as a second line chemotherapy in the refractory ovarian carcinoma cases. Pre-exposure to cisPt based chemotherapy appears to result in the emergence of cisPt resistance, elevated intracellular GSH levels as well as p53 positivity. A statistically significant correlation was also observed between ADR and EPR resistance and p53 positivity (P < 0.01 and 0.05 respectively).

Modulation of in vitro chemosensitivity by extracellular Ca++ in adriamycin sensitive and resistant P388 leukemic cells.

P388 mouse lymphocytic leukemia cells sensitive (P388/S) and resistant to adriamycin (P388/Adr), respectively, were exposed in vitro to 3 dose concentrations of adriamycin, mitoxantrone, vincristine and cisplatin in the presence and absence of extracellular Ca++ at 37 degrees C for 1 h. The absence of extracellular Ca++ enhanced the cytotoxicity of all the four drugs by 25 to 30% in P388/S cells. P388/Adr cells retained their resistance to adriamycin irrespective of the presence or absence of Ca++, however, vincristine and cisplatin to which P388/Adr cells, in normal course, show cross-resistance, exhibited a 30-40% enhancement of cytotoxicity in the absence of extracellular Ca++. Cross-resistance of P388/Adr to mitoxantrone was totally circumvented in the absence of extracellular Ca++.

Modification of tumor cell sensitivity to antineoplastic agents lonidamine and bouvardin (NSC 259968) at elevated temperatures.

Lymphocytic leukemia P388 and Sarcoma-180 cells were exposed to various concentrations (0.01 mM to 0.04 mM) of lonidamine at 37 degrees C and 43 degrees C for 30 min and 60 min in vitro. Similarly combined effect of lonidamine and bouvardin on these tumor cells was also assessed at 37 degrees C and 43 degrees C. The effect was evaluated by comparing the rate of 3H-thymidine incorporation in treated cells to that of control cells. It was observed that at 37 degrees C lonidamine did not exert cytotoxic effect on P388 cells at prescribed time interval. Sarcoma-180 cells, however, showed significant sensitivity to the drug at 37 degrees C. Lonidamine exhibited greater cytotoxicity at 43 degrees C towards both P388 and Sarcoma-180 cells at 30 and 60 min exposure. Lonidamine also enhanced cytotoxicity of bouvardin in P388 and reversed the natural resistance of Sarcoma-180 cells to bouvardin at 37 degrees C.

Effect of mitoxantrone on human chronic myeloid leukemia cells in vitro, combined with hyperthermia.

Mitoxantrone, a new anticancer drug has DNA-binding properties similar to anthracycline antibiotics. In the present studies, effect of the drug has been tested in vitro on human chronic myeloid leukemia cells at 37 degrees C and 42 degrees C. Inhibition of 3H-tritiated thymidine incorporation in the drug-treated cells compared with untreated cells has been used as the parameter of cytotoxicity of the drug and hyperthermia. Cell samples from 11 CML patients who did not receive any chemotherapy showed less response to the drug at 0.5 micrograms/ml and 1 microgram/ml at 37 degrees C. Exposure of CML cells to 42 degrees C for 2 h indicated 13 to 44% inhibition in 3H-TdR incorporation. However, when CML cells were exposed to mitoxantrone for 2 h at 42 degrees C the 3H-thymidine incorporation was inhibited to the extent of 27 to 71%, indicating greater cellular damage with this combination.

Potentiation of adriamycin cytotoxicity in P388 murine leukemia sensitive and resistant to adriamycin by use of lonidamine and hyperthermia.

The in vitro effect of adriamycin (ADR) and lonidamine alone and in combination, at 37 degrees C and 43 degrees C, was investigated on murine leukemia P388 sensitive (P388/S) and resistant (P388/ADR) to adriamycin. The sensitive and the resistant cells were exposed in vitro with and without the drugs for 1 h at 37 degrees C and 43 degrees C. These cells were inoculated ip (10(6) cells/mouse) into groups of BDF1 mice. Cytotoxic effect of the treatment was assessed on the basis of percentage increase in life span (% ILS) of these animals, compared to the animals receiving cells which did not receive any treatment but exposed only to 37 degrees C for 1 h. It was observed that exposure of P388/ADR cells to lonidamine or adriamycin alone at 43 degrees C for 1 h resulted in greater cell kill, thus enhancing the % ILS of the experimental animals receiving those cells, compared to that of mice receiving the cells exposed to the same drugs for 1 h at 37 degrees C. However, the combination of lonidamine (0.02 mM) and adriamycin (10 micrograms/ml) at 43 degrees C for 1 h showed more than a synergistic effect, resulting in a % ILS of 120. Similar results were seen in the case of P388/S; however, the observations pertaining to P388/ADR are encouraging, since the mode of treatment has reversed the acquired resistance of P388 leukemia cells to adriamycin.

Alteration in natural resistance of sarcoma 180 tumor to Bouvardin (NSC 259968) following hyperthermia.

Sarcoma-180 (S-180) tumor cells grown in Swiss mice displayed natural resistance to Bouvardin (NSC 259968) when administered alone in a single dose or in multiple doses. Hyperthermia treatment (43 degrees C for 1 hr) alone did not show any tumor growth reduction. However, the drug combined with hyperthermia markedly reduced tumor growth suggesting that hyperthermia alters the natural resistance of S-180 cells to Bouvardin.

Effect of hyperthermia alone and in combination with anticancer drugs on the viability of P388 leukemic cells.

Effect of local tumor hyperthermia (42 degrees C) at various intervals ranging from 1 to 5 h and in combination with antineoplastic drugs was investigated on P388 murine lymphocytic leukemic cells by using an in vitro-in vivo bioassay method. It was observed that a 1-h exposure resulted in a one log cell kill. In combination studies with hyperthermia and anticancer drugs, 1-h exposure to hyperthermia along with 10 micrograms/ml in vitro concentration of adriamycin (NSC 23127), vincristine (NSC 67574), or 5-fluorouracil (NSC 19893) resulted in the synergistic cell killing action against P388 leukemic cells. However, cyclophosphamide (NSC 26271) and cytosine arabinoside (NSC 63878) did not show any enhanced therapeutic effect.

Differential response of retinoic acid pretreated human synovial sarcoma cell line to anticancer drugs.

The response of tumorigenic human synovial sarcoma (HSS) cell line to 10(-5)M optimum concentration of retinoic acid (RA) included changes in morphology, growth rate, suppression of anchorage-independent growth, induction of high alkaline phosphatase activity and excessive secretion of a 68 kDA glycoprotein of unknown function. HSS cells pretreated with 10(-5)M RA exhibited differential response to 3 potent anticancer drugs, namely cisplatin, vincristine and adriamycin. Sensitivity of the cells to cisplatin was found to be considerably enhanced after exposure to retinoic acid.

Inhibition of macromolecular synthesis in P388 mouse leukemia ascites cells by bouvardin (NSC 259968).

Bouvardin, a new antineoplastic plant product, inhibits macromolecular synthesis in P388 cells in a dose-dependent manner. At the same concentration of bouvardin, protein synthesis was inhibited to a greater extent than the synthesis of DNA and RNA. There was a reversal of inhibition of both DNA and RNA synthesis after the cells were washed free of bouvardin. However, there was partial reversal of inhibition of protein synthesis when the cells were washed free of the drug.

Tween-80 alters natural resistance of sarcoma-180 to bouvardin (NSC 259968).

Sarcoma-180 tumour (S-180) exhibits natural resistance to bouvardin (NSC 259968), a protein synthesis inhibitor that also inhibits RNA and DNA synthesis when administered over a range of non-toxic doses using 0.9% NaCl as a vehicle. However, using Tween-80 as a vehicle, there is a substantial enhancement of cytotoxicity and a subsequent increase in the life span of animals bearing the S-180 tumour. This observation was substantiated in vitro by exposing S-180 cells to 10(-6)M bouvardin in the presence and absence of Tween-80. Bouvardin, 10(-6)M, in the absence of Tween-80, inhibited the incorporation of [3H]uridine by 46%, whereas the presence of Tween-80 resulted in a 66% inhibition of uridine incorporation.

Antitumor effect of L-alanosine (NSC 153553) on sensitive and resistant sublines of murine leukemias.

The antitumor action of L-alanosine (NSC 153553) was investigated in murine leukemia P388 (P388/S), P388 resistant to adriamycin (P388/ADR), P388 resistant to vincristine (P388/VCR) and leukemia L5178Y sensitive to L-asparaginase (L5178Y/S). L-alanosine demonstrated good antineoplastic activity against P388/S and P388/ADR, whereas it showed better anticancer activity against P388/VCR and L5178Y/S at the various dose levels employed.

In vitro cytotoxic effect of new diphenylphosphinoethane-copper(I) complexes on human ovarian carcinoma cells.

Five new copper (I) complexes have been tested for their, in vitro cytotoxicity on chinese hamster ovary (CHO) and human ovarian carcinoma PA-1 cell lines using MTT assay. The compounds exhibited encouraging cytotoxicity at of 1, 2, 4 & 8 micrograms/ml doses. They were further tested for cytotoxicity on human ovarian carcinoma cells obtained from five different patients previously untreated with antineoplastic drugs and radiation. Standard antitumor drugs like cis-platin, adriamycin and etoposide were also included as positive control. Cytotoxicity of compounds C3, C4 and C5 (IC50 0.7, 1.25 and 1.4 micrograms/ml respectively) was found to be superior to adriamycin (IC50 2.8 micrograms/ml) but less effective than cisplatin (IC50 < 0.1 microgram/ml) on human ovarian carcinoma cells.