Human Breast Carcinoma Xenografts Research Articles

Antitumor activity of paclitaxel against human breast carcinoma xenografts serially transplanted into nude mice

Antitumor activity of paclitaxel against human breast carcinoma xenografts serially transplanted into nude mice

Antitumor effect of trimelamol against human breast carcinoma xenografts in nude mice

The antitumor effect of N-2, N-4, N-6-trihydroxymethyl-N-2, N-4, N-6-trimethylmelamine (trimelamol), a synthetic analogue of hexamethylmelamine, was investigated using human breast carcinoma xenografts in nude mice. Four tumor models, T-61, Br-10, R-27 and MCF-7 were estrogen receptor (ER)-positive and their growth was estradiol-dependent. The MX-1 model was ER-negative and grew estradiol-independently. Sixty mg of trimelamol per kg dissolved in 5% dimethylsulphoxide (DMSO) with 5% glucose was administered intraperitoneally for 5 days weekly for three weeks. Trimelamol showed potent antitumor activity on T-61 and MX-1 in a dose-responsive manner with a marginal effect on Br-10, whilst R-27 and MCF-7 were insensitive to this agent. This antitumor spectrum on human breast carcinoma xenografts was similar to that of hexamethylmelamine previously reported using the same xenograft models. Trimelamol is water-soluble and does not require metabolic activation which is needed for hexamethylmelamine. These advantages allow the paraenteral administration of trimelamol, and warrant the further investigation of this drug for breast carcinomas.

Efficacy of lonidamine combined with different DNA-damaging agents in the treatment of the MX-1 tumor xenograft.

Lonidamine is an antitumor agent with a peculiar mechanism of action, since it differentially impairs the energy metabolism of normal and neoplastic cells. We investigated the effects of lonidamine on the activity of DNA-damaging antitumor agents against the MX-1 human breast carcinoma xenograft. Athymic mice bearing measurable s.c. tumors were treated by a single injection of doxorubicin (i.v.), cyclophosphamide (i.v.), or cisplatin (i.p.) followed by repeated daily injections of lonidamine (i.p. or p.o.). A potentiation of the activity of all these DNA-damaging drugs was achieved when each was given in combination with lonidamine, but for doxorubicin and cyclophosphamide the increase in antitumor activity paralleled the increase in lethal toxicity. In contrast, a therapeutic advantage of the combination was achieved for cisplatin and lonidamine as compared with cisplatin alone. Indeed, 6 mg/kg of cisplatin plus lonidamine cured all tumors, whereas the maximum tolerated dose of cisplatin alone (12 mg/kg) cured only six of eight tumors. In addition, the study indicated that the duration of lonidamine administration after injection of the cytotoxic drug influenced the tumor response and that prolonged treatment resulted in greater efficacy. These results document the ability of lonidamine to modulate the pharmacological activity of DNA-damaging drugs, thus suggesting that lonidamine may be a clinically useful cisplatin modulator.

Tentiation of antitumor activity of mitomycin C by estradiol: Studies of human breast carcinoma xenografts serially transplanted into nude mice

Tentiation of antitumor activity of mitomycin C by estradiol: Studies of human breast carcinoma xenografts serially transplanted into nude mice

Potentiation of antitumor activity of mitomycin C by estradiol: Studies of human breast carcinoma xenografts serially transplanted into nude mice

The effect of experimental cancer chemotherapy with mitomycin C (MMC) was studied using three estrogen-receptor (ER)-positive (MCF-7, R-27, and Br-10) and one ER-negative (MX-1) human breast carcinoma xenograft serially transplanted into nude mice, and the effect of estradiol (E2) priming on the antitumor activity of MMC was investigated. Intramuscular injection of E2 at 1 mg/kg changed the ER state and increased the growth fraction detected by flow cytometry, although the growth rate of ER-positive tumors was not effective by E2 priming. MMC suppressed the growth of the four xenografts in a dose-dependent manner. When 1 mg/kg E2 was administered 1 h before MMC treatment, which was given intraperitoneally at a dose of 3 mg/kg, the antitumor activity of MMC was increased in comparison with MMC alone in ER-positive strains, although the effect of MMC on MX-1 was not changed by E2-priming. Priming with E2 at this dose increases the growth fractions of ER-positive breast carcinoma cells, which are sensitive to MMC, resulting in increased antitumor activity of MMC. This E2-primed MMC chemotherapy may be of value in the treatment of ER-positive human breast cancer.

A Phase I Dose Escalation Trial of Intravenous Treosulfan in Refractory Cancer

Background: Treosulfan (Ovastat®), a bifunctional alkylating cytostatic, indicated for the treatment of advanced ovarian carcinoma, was recently found to be active in human lung and breast carcinoma xenografts. Moreover, toxicological evaluation as well as clinical experience revealed the lack of significant nonhematological toxicity which makes treosulfan a promising candidate for high-dose chemotherapy combined with autol-ogous blood stem-cell reinfusion. As a prerequisite for clinical high-dose studies, a formal phase I dose escalation without stem-cell reinfusion was conducted to reassess the maximum tolerated dose and dose-limiting toxicity of treosulfan after intravenous short-term infusion. Patients: A total of 12 patients with chemotherapy-refractory advanced cancer were entered at 3 dose levels (8 g; 10 and 12.5 g/m2 treosulfan i.v). Most patients suffered from advanced small-cell lung cancer (5 patients) or ovarian carcinoma (3 patients). Results: The maximum tolerated dose of treosulfan in this group of heavily pretreated patients was 10 g/m2. The dose-limiting toxicity was reversible thrombocytopenia. There were no nonhematological side effects exceeding WHO grade 2. Conclusions: This phase I dose escalation trial confirmed the lack of significant nonhematologic side effects of treosulfan although a dose of 12.5 g/m2 was infused. A subsequent phase I study of high-dose treosulfan followed by peripheral blood progenitor cells has therefore been initiated.

Radioimaging of human breast carcinoma xenografts in mice by [ 123I]-labeled Z-17α-iodovinyl-11β-chloromethyl-estradiol

Z-17α-iodovinyl-11β-chloromethyl-estradiol (Z-CMIV), a new selective estradiol derivative, can easily be labeled with high efficiency by radioactive iodine isotopes. Biodistribution studies and quantitative scintigraphic imaging of human breast carcinoma xenografts in mice demonstrated continuous and selective accumulation of the [ 123I]Z-CMIV, in estrogen receptor (ER)-positive target tumors, with significantly high target/nontarget ratio up to 48 h post-injection. A receptor-mediated mechanism of concentration of Z-CMIV in target tissues was confirmed by scintigraphic imaging and by biodistribution studies.

In vivo antitumor activity of hexamethylmelamine against human breast, stomach and colon carcinoma xenografts.

We have evaluated the antitumor activity of Altretamine (hexamethylmelamine, HMM) on human carcinoma xenografts serially transplanted in nude mice. Five human breast carcinoma xenografts, MX‐1, T‐61, MCF‐7, R‐27 and Br‐10, were inoculated subcutaneously into female nude mice. Two human stomach carcinoma xenografts, SC‐1‐NU and St‐4, and three human colon carcinoma xenografts, Co‐3, Co‐4 and Co‐6, were inoculated subcutaneously into male nude mice. One pellet of 17β‐estradiol (0.1 mg/mouse) was inoculated subcutaneously in the mice transplanted with MCF‐7 when the tumors were inoculated. HMM was administered per os daily for 4 weeks. MX‐1 and T‐61 tumors regressed completely after treatment with HMM at a dose of 75 mg/kg (the maximum tolerated dose: MTD) for MX‐1 and 25 mg/kg for T‐61. Br‐10 was sensitive, whereas MCF‐7 and R‐27 were resistant to HMM at its MTD. HMM exerted the most potent antitumor effect against T‐61. Against MX‐1, it exerted an antitumor effect equivalent to that of cisplatin or cyclophosphamide. In addition, this agent was effective against all stomach and colon carcinoma xenografts, in particular St‐4 (T/C%= 10.7: the mean tumor weight of treated group/the mean tumor weight of control group) and Co‐3 (T/C%=31.5%) which are insensitive to presently available agents. HMM seems worthy of further clinical investigation as a candidate agent to treat breast, stomach, colon and other carcinomas.

The decreased influence of overall treatment time on the response of human breast tumor xenografts following prolongation of the potential doubling time (T pot)

Purpose : Repopulation during fractionated radiotherapy has been postulated to result in a significant loss in local control in rapidly proliferating tumors. Clinical data suggest that accelerated fractionation schedules can overcome the influence of repopulation by limiting the overall treatment time. Unfortunately, accelerated therapy frequently leads to increased acute reactions, which may become dose limiting. An alternative to accelerated fractionation would be to decrease the rate of repopulation during therapy. To test the potential efficacy of this alternative, we examined the effect of reducing tumor proliferation rate on the response of MCF-7 human breast carcinoma xenografts treated with a short vs. a long course of fractionated therapy. To reduce the proliferation rate, we deprived nude mice transplanted with MCF-7 xenografts of the growth-stimulating hormone estradiol (E 2). We have previously reported that E 2 deprivation increases the potential doubling time (T pot) for MCF-7 xenografts from a mean of 2.6 days to 5.3 days ( p < 0.001). Methods and Materials : E 2-stimulated and E 2-deprived MCF-7 breast carcinoma xenografts were clamped hypoxically and irradiated with four fractions of 5 Gy each, using either a short (3-day) or long (9-day) treatment course. E 2 stimulation was restored in all animals at the completion of irradiation. Radiation response was determined by regrowth time and regrowth delay of the irradiated tumors as compared to unirradiated controls. Results : Prolongation of therapy in rapidly proliferating, E 2-stimulated tumors (T pot ≈ 2.6 days) resulted in a significant decrease in regrowth time in two identical experiments. With results pooled for analysis, the regrowth times for the short and long treatments were 62 and 32 days, respectively (combined p < 0.001). The shorter regrowth times suggest that there was less overall tumor damage with the longer fractionated radiotherapy course. No significant difference in regrowth time was observed in the more slowly proliferating, E 2-deprived tumors (T pot ≈ 5.3 days) treated with either the short or long regimen. Median regrowth times were 48 and 54.5 days for the short and long treatments, respectively (combined p = 0.14). Similar changes were observed in regrowth delay. Conclusions : Reduction in the rate of cell proliferation, induced by E 2 deprivation in MCF-7 human breast xenografts during fractionated radiotherapy, resulted in a significantly decreased dependence on overall treatment time in comparison to the more rapidly proliferating E 2-stimulated tumors. This model suggests that pharmacologically induced reduction in the rate of tumor cell proliferation during a course of fractionated radiotherapy may be a viable alternative to accelerated fractionation for the treatment of rapidly proliferating tumors.

Inhibition of growth of human breast carcinoma xenografts by energy expenditure via voluntary exercise in athymic mice fed a high-fat diet.

The purpose of this study was to assess the effect of energy expenditure, via voluntary exercise, on growth of xenografts of human breast carcinomas in athymic nude mice. Sedentary and exercising athymic nude mice bearing subcutaneous grafts of MDA-MB231 human breast carcinomas were fed daily a purified high-fat diet at 10% less than ad libitum to ensure an equal quantity of diet (energy) consumption for each sedentary and exercising mouse. The sedentary and exercising mice were housed singly; the exercising mice had, in addition, access to an activity wheel (24 hrs/day). Growth of human breast carcinomas (carcinoma volumes) was evaluated during a five-week periods. Mean running activities of individual mice over the five-week period ranged from < 1 to 7.9 miles/day. Growth of the human breast carcinomas was significantly inversely correlated with the mean number of miles that each mouse ran per day (p < 0.018). Upon separation of these mice into two running groups, i.e., those that averaged 2.7-4.7 miles/day and those that averaged > 4.7 miles/day, carcinoma growth was 83% of sedentary controls in the former group (p = 0.305) and 59% of sedentary controls in the latter group (p = 0.039). These results provide evidence that energy expenditure, via voluntary use of an activity wheel, can reduce significantly the growth of human breast carcinomas maintained in athymic nude mice.

Evaluation of antitumor activity of navelbine (vinorelbine ditartrate) against human breast carcinoma xenografts based on its pharmacokinetics in nude mice

The in vitro antitumor activity of navelbine (NVB, KW-2307), a newly synthesized vinca alkaloid, was compared with that of adriamycin (ADM) against human breast carcinomas inoculated into nude mice at the maximum tolerated dose (MTD) and clinically equivalent dose (CED). The plasma levels of NVB after intravenous injection into nude mice at doses of 1.2 and 4.8 mg/kg diminished rapidly during the early phase (0-1 h), followed by a very long shallow one. NVB was still detected 96 h after administration at a dose of 4.8 mg/kg. The pharmacokinetic parameters of NVB in plasma indicated that NVB extensively distributes to tissues. The CED of NVB was provisionally decided to be 4.8 mg/kg based on the comparison of AUC values at 24-infinity h between human patients and nude mice. When compared by a single injection of MTD (NVB, 16 mg/kg; ADM 12 mg/kg), NVB was effective against all four tumor lines, MC-2, MC-8, MMKY and H-31, while ADM was effective only against H-31. On the other hand, the body weight loss by NVB was mild as compared with that by ADM, indicating that the antitumor activity of NVB is superior to that of ADM at their MTDs. A single injection of NVB at its CED (4.8 mg/kg) produced a poor antitumor effect and no or little toxicity in terms of body weight loss, as compared with those at MTD. However, when NVB was administered intermittently at CED, it exhibited significant antitumor activity against three tumor lines. The body weight loss was still mild even on this intermittent schedule.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro and in vivo characterization of BR96 sFv-PE40. A single-chain immunotoxin fusion protein that cures human breast carcinoma xenografts in athymic mice and rats.

Abstract BR96 sFv-PE40 is a single-chain immunotoxin fusion protein targeted to the Ley Ag, which is expressed in many different human carcinomas as well as in normal gastrointestinal epithelium of humans and certain animals, including athymic rats but not mice. In vitro binding analysis determined that BR96 sFv-PE40 was similar in affinity to BR96 Fab. BR96 sFv-PE40 internalizes rapidly, similar to BR96 IgG. H3396 cells, derived from metastatic human breast carcinoma, have been established as tumor xenografts in estradiol-supplemented athymic mice and rats. H3396 tumor xenografts established in athymic mice (up to 350 mm3) and rats (up to 100 mm3) completely regressed after i.v. administration of BR96 sFv-PE40, given as 0.625 mg/kg (1.975 mg/m2) every 4th day for a total of five doses (mice) or 0.25 mg/kg (1.475 mg/m2) every 4th day for a total of four doses (rats). The tumors remained regressed for the duration of the study (&amp;gt; 85 days post-implant), which represents &amp;gt; 10 doubling times, indicating that the animals were cured. There was no toxicity in rats receiving a curative dose of 0.25 mg/kg, although liver and lung toxicity could be detected at a 16 times higher dose, 4 mg/kg or 23.6 mg/m2. We conclude, therefore, that BR96 sFv-PE40 can cure tumor xenografts at well tolerated doses and also in the presence of Ley expression in normal tissues.

Reversal of the human and murine multidrug-resistance phenotype with megestrol acetate.

MA is an orally active PG derivative with an excellent safety profile that is used primarily for the treatment of carcinomas of the breast and endometrium. We investigated the potential application of MA as an MDR-reversal agent using cell culture and human tumor xenograft models. The reversing activity of MA in vitro was compared with that of PG and VER in two human MDR cell lines, the colon carcinoma HCT-116/VM46 and the breast carcinoma MCF-7/ADR, and in a murine cell line, J774.2. At concentrations as low as 3 microM, MA was capable of partially restoring sensitivity to Act D in the HCT-116/VM46 cells and sensitivity to DOX in the MCF-7/ADR cells. Although less effective than VER, MA was about 2.5 times more potent than PG in reversing MDR at equimolar concentrations. Increased accumulation of DOX in drug-resistant cells that were treated simultaneously with MA was observed by flow cytometry. In vivo, using established human colon and breast carcinoma xenografts implanted s.c. in athymic mice, the combined therapy with MA and DOX resulted in enhanced antitumor activity relative to that of DOX alone in the MDR sublines. These results suggest that MA may be a promising clinical MDR-reversing agent.

Radioimmunoimaging of human breast carcinoma xenografts in nude mouse model with 111In-labeled new monoclonal antibody EBA-1 and F(ab′) 2 fragments

Radioimmunoimaging characteristics of a new monoclonal antibody EBA-1 and its F(ab′) 2 fragments utilizing nu/nu mice bearing human breast carcinoma xenografts are described. 111In-DTPA conjugates of EBA-1 localized with tumor/blood ratios of 0.99 ± 0.10 ( P < 0.3) and 4.65 ± 1.60 ( P < 0.05), and localization indices of 1.25 and 2.61 at 24 and 72 h, respectively. A tumor/blood ratio as high as 28.86 ± 6.90 ( P < 0.025) was obtained with EBA-1 F(ab′) 2 radioconjugates at 48 h. These results suggest that EBA-1 and its F(ab′) 2 might be useful reagents in radioimmunoimaging and radioimmunotherapy.

Growth and metastasis of human breast carcinomas with Matrigel in athymic mice.

Immunodeficient athymic mice with human tumor xenografts provide an important in vivo experimental model for cancer research. However, only a limited number of tumor types grow in these animals. For human breast carcinomas, the incidence of tumor-take is 6-15%. Recently, increased incidence of xenograft development in mice has been reported for various human tumors when the tumors were coinjected with Matrigel. We studied the development of human breast carcinoma xenografts in athymic mice with and without coinjection of Matrigel. Tumors developed in only 7.3% of enzyme-dispersed tumors injected subcutaneously in saline solution alone. None of these tumors metastasized to distant sites. On the other hand, 50% of enzyme-dispersed tumors coinjected with Matrigel developed xenografts; four out of five of these tumors metastasized to distant sites. Our data from the recent study suggest that, in athymic mice, Matrigel not only enhanced breast tumor growth but also facilitated tumor metastasis.

Antitumor effect of triphenylethylene derivative (TAT-59) against human breast carcinoma xenografts in nude mice.

The antitumor activity of a newly synthesized triphenylethylene derivative [(E)-4-[1-[4-[2-(dimethylamino)ethoxy-phenyl]-2-(4-isopropyl)phenyl-1- butenyl] phenyl monophosphate] (TAT-59) was investigated against human breast carcinoma xenografts in nude mice with reference to the changes of hormone receptors. Five strains (MCF-7, Br-10, R-27, ZR-75-1, and T-61) used for the experiments possessed cytosol estrogen receptor (ER), and their growth was estradiol dependent. Five mg of TAT-59 and tamoxifen citrate (TAM) per kg were administered p.o. daily except Sunday. TAT-59 showed a positive antitumor effect against MCF-7 and R-27, whereas TAM was effective on MCF-7, and their adverse effects detected by mortality rate, body weight loss, and spleen weight loss were similar to each other. The reduction of ER and production of progesterone receptor (PgR) after the treatment with TAT-59 were more potent than after TAM, suggesting that TAT-59 exerts its antitumor effect through binding to ER. These findings suggest that TAT-59 might merit use in clinical trials with breast cancers.

Recombinant human interferon-alpha 2a increases hormone receptor level of a human breast carcinoma xenograft in nude mice and enhances the anti-proliferative activity of tamoxifen.

The effect of recombinant human interferon‐α2a (rhIFN‐α2a) on the hormone receptor level and antitumor activity of tamoxifen (TAM) was investigated in nude mice using ZR‐75‐1, an estrogen receptor (ER)‐positive, and progesterone receptor (PgR)‐negative human breast carcinoma xenograft. ER levels (maximum binding sites) of tumors treated with rhIFN‐α2a at a dose of 6 × 104 U/mouse/ day for 1 or 3 wk were not significantly different from the control, whereas those with rhIFN‐α2a at a dose of 6 × 104 U/mouse/day for 1 or 3 wk were higher than the control (3.9‐ to 4.4‐fold) with a significant difference at P < 0.01. The increase of ER by rhIFN‐α2a was investigated using a sucrose density gradient method. The peak was only seen at 8S in both rhIFN‐α2a‐treated tumor and control ER, and the sedimentation patterns were almost the same, suggesting that both ERs were essentially equivalent. On the other hand, PgR of all the treated groups could be detected, while that of the control group was undetectable. The antitumor effect of the combination treatment of rhIFN‐α2a and TAM was compared with those of single treatments. While rhIFN‐α2a at a dose of 6 × 105 U/mouse/day and TAM did not show a combination effect, rhIFN‐α2a at a dose of 6 × 104 U/mouse/day and TAM showed a synergistic combination effect, and ER was decreased to the threshold of detection by the combination treatment. These findings indicated that a low dose of rhIFN‐α2a increased the ER levels of ER‐positive human breast cancer in vivo as well as in vitro and enhanced the anti‐proliferative effect of TAM, and the newly synthesized ER was essentially the same as the original ER.

Hyperthermia enhances mitoxantrone cytotoxicity on human breast carcinoma and sarcoma xenografts in nude mice

In this preclinical in vivo study, we measured antitumor response, local side effects and systemic toxicity of locally applied water-bath hyperthermia given alone or simultaneously with mitoxantrone (3 mg/kg b.w. i.v.; LD 10) on a human derived breast carcinoma (MX 1) or a human sarcoma (S 117) transplanted to female athymic (nude) mice. A single hyperthermia treatment at a tumor temperature up to 43°C for 1 hr caused in both tumor lines only minor tumor regressions and transient tumor growth delay. However, the antitumor effect of mitoxantrone was significantly enhanced by local hyperthermia at 42°C and particularly at 43°C. In both tumor lines complete tumor regressions were achieved only if mitoxantrone was combined with hyperthermia. Undesired side effects and drug toxicity were not enhanced by hyperthermia. According to in vitro data and the results of the present in vivo study mitoxantrone seems to be a good candidate for clinical trials in combination with locoregional hyperthermia.

MRI contrast-dose relationship of manganese(III)tetra(4-sulfonatophenyl) porphyrin with human xenograft tumors in nude mice at 2.0 T

Previously we reported that Mn(III)tetra(4-sulfonatophenyl) porphyrin, MnTPPS 4, is a contrast agent which can effectively enhance tumor detection by MRI. By imaging 30 additional athymic nude mice bearing subcutaneous MCF-7 WT human breast carcinoma xenografts, we have extended dose-contrast relationships over a wide range of intraperitoneal (IP) doses ranging from 0.025 to 0.50 mmol/kg. The benefits of IP injection are higher possible doses on a volume basis and a reduction in toxicity versus IV administration. Full coronal cross-section images have been obtained on a 2-T spectrometer. Although individual tumor masses displayed different distribution patterns, reflective of their internal morphology, single doses of 0.10 mmol/kg or greater were necessary to produce a detectable effect. At a dose of 0.50 mmol/kg, marked enhancement was produced. Multiple small dosages administered over the course of several days before imaging did not produce increased enhancement. Preliminary results on the new porphyrin derivative, MnTPPS 3, indicate that the ratio of the toxic dose to the effective dose may be adjustable to render this class of agents clinically useful.

Tumor localization in nude mice bearing human breast carcinoma xenografts using 111In-DTPA conjugates of monoclonal antibodies

Biodistribution of monoclonal antibody T43 and its F(ab′) 2 111In-DTPA conjugates were determined in nu/nu mice bearing human breast tumor and rat pituitary tumor xenografts. T43 localized in the target tumor with tumor blood ratios of 3.9 ( P < 0.01) and 4.5 ( P < 0.05) at 48 and 72 h, respectively. T43 F(ab′) 2 fragments localized with tumor blood ratio of 14.2 ( P <0.1) at 72 h. Tumors as small as 4mm were detected without computer subtraction technique. These studies suggest that T43 and T43 F(ab′) 2 might be useful reagents in radioimaging.