Identification of a subpopulation of MeCCNU resistant cells in previously untreated Lewis lung tumours

Stephens, T C; Adams, K; Peacock, John

doi:10.1038/bjc.1984.141

Cited by 11 publications

(5 citation statements)

References 8 publications

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“…Although inherently sensitive cells might be protected in kinetic, pharmacological or environmental sanctuaries, the apparent rarity of such sanctuaries makes this suggestion, to us, unlikely. Only 1 in 105 tumour cells are resistant according to the survival curve published in our previous paper (Stephens et al, 1984) and this is supported by growth delay data. The growth delays for wildtype and sensitive tumour lines treated with 25mg kg-I MeCCNU were 15 to 20 days (Table I) and assuming a 1 day doubling time for surviving cells, this translates into 5 to 6 decades of cell killing.…”

Section: Discussionsupporting

confidence: 68%

“…administration to mice of MeCCNU, CCNU, BCNU, cyclophosphamide (CY), melaphalan and cis-dichlorodiammine platinum (cis-Pt) have all been described in previous publications (Rose et al, 1980;Stephens et al, 1984).…”

Section: Methodsmentioning

confidence: 99%

“…tumours for regrowth delay studies was described in detail by Stephens et al (1984). Since at low drug doses tumours often did not shrink below their treatment volume, the response of each individual tumour was evaluated as the time to grow to 4 x its size at the time of treatment (T4 x ).…”

Section: Measurement Of Tumour Cell Survivalmentioning

confidence: 99%

“…In a recent publication we presented data showing that, although previously untreated Lewis lung tumours appeared to be very sensitive to the cytotoxic nitrosourea MeCCNU using a clonogenic cell survival endpoint, they infact contained a very small subpopulation of cells that were highly resistant to this agent (Stephens et al, 1984).…”

mentioning

confidence: 99%

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Emergence of nitrosourea resistant sublines of Lewis lung tumour following MeCCNU treatment in vivo

Stephens¹,

Adams²,

Peacock³

1986

Br J Cancer

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Section: Discussionsupporting

confidence: 68%

Section: Methodsmentioning

confidence: 99%

Section: Measurement Of Tumour Cell Survivalmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Emergence of nitrosourea resistant sublines of Lewis lung tumour following MeCCNU treatment in vivo

Stephens¹,

Adams²,

Peacock³

1986

Br J Cancer

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“…The tumourbearing leg was passed through holes of known diameter in a perspex disc and the size of the tumour was taken to be the size of the largest hole through which the tumour would pass without resistance (Stephens et al, 1984). This size was converted into tumour weight by comparison with a calibration curve which was constructed by measuring a number of tumours, dissecting them out and weighing them.…”

Section: Methodsmentioning

confidence: 99%

Development of drug resistance in a murine mammary tumour

McMillan¹,

Stephens²,

Steel³

1985

Br J Cancer

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Sunmnary The development of resistance to melphalan, cis-platinum and cyclophosphamide has been examined in the MT murine mammary carcinoma. A gradual decrease in therapeutic response was detected using growth delay and clonogenic cell survival during repeated drug treatment. A slow rate of resistance development, a gradual change in the slope of the dose-survival curves and the inability of 180mgkg-cyclophosphamide to bring about a reduction in tumour response at a faster rate than 60mg kg-1 cyclophosphamide suggest that resistance development was not due to the selection of a pre-existing highly drug resistant sub-population of tumour cells. Partial drug-resistance is proposed as one possible reason for the apparent inconsistency between these data and existing models of drug-resistance development. The drugresistant lines were characterized for karyotype, DNA content and cell volume, but only the cyclophosphamide-resistant line showed any significant difference from the wild-type tumour. Cross-resistance studies revealed some inconsistencies with previous reports. Also, resistance to cyclophosphamide developed more quickly in the line which was resistant to melphalan, than in the wild-type tumour, despite the initial appearance of little cross-resistance. This increased rate of resistance development may be important in salvage chemotherapy.

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Testicular cancer in nine northern european countries

Adami

Bergström

Möhner³

et al. 1994

Intl Journal of Cancer

443

219

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The incidence of testicular cancer was examined in the Nordic and Baltic countries, Poland and Germany by collaboration among 10 cancer registries. Population-based registers were used to analyze a total of 34,309 cases, diagnosed from the start of registration (varying from 1943 in Denmark to 1980 in Latvia and Lithuania) through 1989. An approximately 10-fold geographical variation was found in 1980, with the highest age-standardized incidence rate (7.8 per 10(5); world standard population) in Denmark and the lowest (0.9) in Lithuania. During the entire period of registration, incidence increased rapidly in all countries, by 2.3 to 3.4 per cent annually in the Nordic countries and by about 5 per cent in Poland and Germany; there was some evidence of a slower increase in Denmark and Poland after 1975. The rising trend was more pronounced for ages below 30. The age-specific incidence peaked in all countries at ages 25 to 34, but the geographical variation was considerable. Our data indicate that environmental influences on testicular cancer are strong. Exposure to causal factors mostly takes place early in life, shows substantial geographical variation, and increases over time, so that the age-standardized incidence doubles every 15 to 25 years. New aetiological hypotheses are needed to accommodate these salient features of the descriptive epidemiology, since risk factors considered so far cannot explain the observed pattern.

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Identification of a subpopulation of MeCCNU resistant cells in previously untreated Lewis lung tumours

Cited by 11 publications

References 8 publications

Emergence of nitrosourea resistant sublines of Lewis lung tumour following MeCCNU treatment in vivo

Emergence of nitrosourea resistant sublines of Lewis lung tumour following MeCCNU treatment in vivo

Development of drug resistance in a murine mammary tumour

Testicular cancer in nine northern european countries

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