1. LIFESTYLE OF PHYSICAL ACTIVITY ON TESTOSTERONE, IGF-1, AND LNCaP PROSTATE TUMOR CELL GROWTH IN VITRO AMONG AFRICAN-AMERICAN MEN
DEREK R. JONES, COURTNEY A. HUDSON, MORGAN GRIMES, VERNON BOND, JR, Ed. D.
Howard University, Department of Health, Human Performance and Leisure Studies, Washington, DC.
ABSTRACT INTRODUCTION RESULTS
Prostate cancer is highest among African-American men in the It has been estimated that 15%-30% of men over 50, and about 80% Mean age(19.88±.5805 yrs vs. 20.11±.3889 yrs [P>0.05]), height(172.8
world. To investigate the influence of physical activity on of men over 80 harbor microscopic, undiagnosed prostate cancer ±3.369 cm vs. 180.3 ±3.367 cm [P>0.05]), weight(82.75 ±6.079 kg vs.
established biochemical risk factors for developing prostate cancer, (Pca) in the United States.(1) PCa is diagnosed in 1 of 6 U.S. men; 75.44 ±4.770 kg [P>0.05]), and heart rate(183.3 ±2.403 bpm vs. 187.4
however it is only fatal in 3% of men.(2) Variations in the clinical ±2.926 bpm [P>0.05]) were similar between groups, and there were
the growth rate of prostate tumor cells, as a function of physical
incidence of Pca are present, including an alarmingly high rate of
activity, were examined in seventeen healthy young adult African no differences between groups for resting systolic blood pressure
African American incidence versus other non-western cultures.
American men. Nine of the participants exercise-trained with a (SBP) (123.3 ±5.891 mmHg vs. 121.6 ±5.993 mmHg [P>0.05]),
Further, in addition to higher rates of clinical incidence and higher
maximal oxygen uptake (VO2max) > 40 ml.kg-1.min-1 (Physically diastolic blood pressure(67.63 ±2.471 mmHg vs. 68.44 ±2.987
death rates, it has been observed that the onset of PCa occurs at an
Active Group), and 8 of the participants were non-exercise trained earlier age in African Americans in the United States.(3) The mmHg [P>0.05]) or Testosterone level (???? ±???? Ng/ml vs. ?????
with a VO2max ≤ 38 ml.kg-1.min-1 (Physically Inactive Group). The etiology of prostate cancer is not known. Studies have shown ±?????ng/ml [P>0.05]). In association with the VO2max peak
cycle ergometer was used to determine VO2max using the indirect lifestyle of physical inactivity affects the growth of androgen variation, the IGF-1 level was significantly lower in the physically
open-circuit calorimetric method. Twelve hours postprandial, dependent tumor cells. The Surgeon General’s Report on Physical active group compared to the physically inactive group (240.5
serum testosterone and insulin growth factor-1 (IGF-1) levels were Activity and Health emphasizes improvement of the quality of life 16.37 ng/ml vs. 319.1 14.46 ng/ml [P<0.05]). Testosterone levels
determined. The androgen dependent LNCaP prostate cancer cells through a lifestyle of physical activity will enhance and prevent were in the direction of being higher in the physically inactive
were cultured in the serum of the physically active and inactive disease. It has been reported that increased occupational of leisure group than the physically active group, but the difference was not
groups and examined for cell growth. Relative growth rate of the time activity reduced the risk for Pca by 10-70% (4). significant. Relative growth rate of the LNCaP tumor cell in vitro
LNCaP tumor cell was 21% higher in the physically inactive group was 21% higher than the physically inactive group in comparison
in comparison to the physically active group (P<0.05). The IGF-1 to the physically active group (P<0.05).
level was significantly lower in the physically active group than
the physically inactive group (240.5 16.37 ng/ml vs. 319.1 14.46
MATERIALS & METHODS Fig. 1 Fig. 2
350
ng/ml) (P<0.05). Based on the data and results, there appear to be 10 0
300
Growth (% Control )
a link between physical activity and relative growth rate of the Seventeen healthy young adult African American men (20±1 yrs) 80 250
served as the study participants. A progressive work bout on the 60
ng/ml
200
LNCaP tumor cell(s) as well as the IGF-1. Further research is 150
cycle ergo meter was used to determine VO2max with the indirect 40
needed to examine the extent of this significance between physical
100
open-circuit calorimetric method according to a standard
20
50
activity and the prevention of prostate cancer. 0 0
incremental cycling protocol. Nine of the participants produced a Physically I nact ive
Serum
Physically Act ive
Serum
Physically I nact ive
Serum
Physically Act ive
Serum
maximal oxygen uptake (VO2max) > 40 ml·kg-1·min-1 and were
PURPOSE deemed physically Active. Eight of the participants produced a
maximal oxygen uptake (VO2max) < 40 ml·kg-1·min-1 and were Fig. 3 Fig. 1 Lymph node cancer of the prostate
cell growth of physically active and
labeled sedentary. Parameters to be measured with Cycle ergo 0 .4
physically inactive groups.
The purpose of the current study is to investigate the influence of meter method included body mass index, age, height, heart rate,
0 .3 5
0 .3
Fig. 2 Insulin-like growth factor-I level in
physical activity on established biochemical risk factors for resting diastolic BP, weight, resting systolic BP and workload which
0 .2 5
physically active vs. inactive group.
ng/ml 0 .2
developing prostate cancer. determined whether a maximum effort had been achieved. Subjects
0 .1 5
Fig. 3 Testosterone level in physically
0 .1
active vs. inactive group.
were twelve hours postprandial. Blood samples were taken from 0 .0 5
0
respective groups, allowed to clot, and then were centrifuged to Physically I nact ive Physically Act ive **P<0.05
HYPOTHESIS obtain serum. Serum was then analyzed for Testosterone and IGF-1
Serum Serum
using enzyme-linked immunosorbent assay (ELISA) kits. Androgen
●Hypothesis 1: The growth rate of LNCaP prostate cancer tumor dependent LNCaP prostate cancer cells were obtained and grown.
Cells were plated in 96-well plates and allowed to attach and
CONCLUSION
cells would be lower in the serum of the physically active group
compared to the serum of physically inactive individuals. stabilize. Serum samples were then added to the wells and cell Lifestyle of physical activity appears to have an influence on risk
growth was determined. Data analysis was performed for control for developing PCa. The results of the present study support the
●Hypothesis 2: The lower growth rate of the LNCaP prostate and active groups. P<0.05 was considered significant. Data are hypothesis of reduced proliferation of LNCaP prostate tumor cells
cancer tumor cells in the physically active group will be associated expressed as means±standard error. in those physically active. Results also support our hypothesis in
with a lower testosterone level. that the lower growth rate of LNCaP cells would be associated
with a lower IGF-I level. Testosterone was in the direction of being
●Hypothesis 3: The lower growth rate of the LNCaP prostate higher in the physically inactive serum but the difference was not
cancer tumor cells in the physically active group will be associated
with a lower IGF-1 level. ACKNOWLEDGEMENTS significant. A possible explanation is that the sex hormone plays a
lesser role. These findings may also explain variations in incidence
among ethnicities and western versus developed regions.