Table 2 Suppression of microtubule dynamic instability in MCF7-EGFP-α-tubulin cells incubated with vehicle, taccalonolide AJ or Paclitaxel

Growth rate (μm/min)

7.5±0.25

7.2±0.3

−5.1

6.9±0.3

−8.50

6.5±0.3

−13.3^**

7.2±0.3

−3.9

6.5± 0.3

−13.3^**

Shortening rate (μm/min)

13.9±0.9

12.0±0.8

−14.0

8.6±0.4

−38.5^***

9.1±0.9

−34.9^***

12.0±0.7

−13.9

8.0±0.5

−42.5^***

Percent Time Growing

35.8

29.2

−18.6

14.9

−58.3

14.9

−58.4

26.0

−27.5

18.2

−49.3

Percent Time Shortening

16.6

13.7

−17.3

9.7

−41.6

9.7

−41.7

11.5

−31.1

7.8

−53.4

Percent Time Attenuated

47.6

57.1

20.1

75.4

59.0

75.4

58.6

62.6

31.6

74.1

55.8

Catastrophe Frequency (per min)

1.8±0.1

1.6±0.2

−8.9

1.2±0.1

−32.8^***

1.2±0.1

−36.1^***

1.4±0.1

−21.1^*

1.3±0.2

−30.0^*

Rescue Frequency (per min)

10.4±0.5

10.5±0.6

0.6

11.6±0.7

11.4

11.0±0.7

5.9

11.2±0.6

7.5

12.8±0.6

22.8^**

Dynamicity

5.1

3.8

−25.3

1.9

−62.3

1.9

−62.1

3.3

−34.1

1.9

−62.33

MTs/Cells Counted

40/18

41/13

41/13

31/12

47/14

30/13

% Dynamic MTs

65

51

41

32

54

44