Two-Pronged Anti-Tumor Therapy by a New Polymer-Paclitaxel Conjugate Micelle with an Anti-Multidrug Resistance Effect

Figures & data

Scheme 1 The schematic diagram of the anti-tumor effect in vivo of PDSP micelles.

Scheme 2 The synthesized route of PDCP and PDSP polymer prodrugs.

Table 1 The Factors and Levels of the Central Composite Design Test

Factors	Levels
	−1	0	1
Hydration temperature X1 (°C)	35	45	55
Ultrasonic power X2 (W)	60	100	140
The counts of ultrasound X3 (Times)	10	20	30

Table 2 The Results of the Central Composite Design Test

No.	Factors			Responsive Values
	X1	X2	X3	Size (nm)	PDI
1	−1	−1	−1	163.4	0.417
2	−1	−1	0	181.4	0.38
3	−1	−1	1	268.8	0.522
4	−1	0	−1	174.9	0.444
5	−1	0	0	207.6	0.426
6	−1	0	1	197.1	0.493
7	−1	1	−1	221.6	0.536
8	−1	1	0	216.8	0.527
9	−1	1	1	279.8	0.581
10	0	−1	−1	179.6	0.408
11	0	−1	0	174.7	0.347
12	0	−1	1	256	0.553
13	0	0	−1	228.7	0.35
14	0	0	0	185	0.404
15	0	0	1	187.6	0.422
16	0	1	−1	202.7	0.359
17	0	1	0	183.3	0.321
18	0	1	1	207.1	0.482
19	1	−1	−1	170.8	0.325
20	1	−1	0	169.9	0.507
21	1	−1	1	223.1	0.521
22	1	0	−1	152.5	0.434
23	1	0	0	142.8	0.437
24	1	0	1	195.4	0.448
25	1	1	−1	232.4	0.51
26	1	1	0	220.8	0.599
27	1	1	1	232	0.532

Figure 1 The particle size and TEM photos of PDCP (A) and PDSP (B) micelles.

Figure 2 The results of in vitro stability and reduction-sensitivity test. (A) Dilution stability. (B) Storage stability. (C) Plasma stability. (D) Reduction-sensitive release in the environment with different levels of glutathione (GSH). (E) Reduction-sensitivity of mPEG-DCA-CC-PTX (PDCP) micelles. (F) Reduction-sensitivity of mPEG-DCA-SS-PTX (PDSP) micelles.

Figure 3 In vitro biosafety tests. (A) Hemolysis (i: Distilled water, ii: Saline, iii-v: mPEG-DCA-SS-PTX (PDSP) at 0.1, 0.3, 0.5 mg/mL, vi-viii: mPEG-DCA-CC-PTX (PDCP) at 0.1, 0.3, 0.5 mg/mL). (B) Hemolysis rate. (C) The cytotoxicity of blank micelle (BM) to HL-7702 cells. (D) The cytotoxicity of PDSP, PDCP, Paclitaxel (PTX) injection and PTX injection+BM to HL-7702 cells at 24 h. (E) The cytotoxicity of PDSP, PDCP, PTX injection and PTX injection+BM to HL-7702 cells at 48 h. Data were presented as mean ±SD. *P<0.05, **P<0.01.

Figure 4 The cytotoxicity of six PTX formulations to SMCC-7721 cells (A and B), MCF-7 cells (C and D), and A549/PTX cells (E and F) at 24 h and 48 h. Data were presented as mean ±SD. The asterisk indicates the statistical significance between other formulations to Paclitaxel (PTX) injection, the rhombus indicates the statistical significance between mPEG-DCA-SS-PTX (PDSP) and PDSP+ glutathione (GSH). *P<0.05, **P<0.01, ***P<0.001, and ^◊P<0.05, ^◊◊P<0.01. BM, PDCP represents blank micelle and mPEG-DCA-CC-PTX, respectively.

Figure 5 The results of in vivo anti-tumor activity of the different Paclitaxel (PTX) formulations (such as PTX injection, mPEG-DCA-CC-PTX (PDCP) and mPEG-DCA-SS-PTX (PDSP)) to H22 tumor in mice. (A) The change in tumor volume and the tumor shape (n=10), **P<0.01, ***P<0.001. (B) The inhibition rate of tumor volume, *P<0.05, ***P<0.001. (C) The change in the bodyweight of mice for 14 days. (D) The curve of mice survival for 14 days.

Figure 6 The images of the heart, liver, kidney, and tumor slices stained with H&E dyes after treatment by the different Paclitaxel (PTX) formulations, such as PTX injection, mPEG-DCA-CC-PTX (PDCP) and mPEG-DCA-SS-PTX (PDSP). Black arrows indicate tissue injury in this area, such as cell degeneration, necrosis, inflammatory cell infiltration and intra-tissue bleeding.

Figure 7 Body distribution of Paclitaxel (PTX) after i.v. administration of mPEG-DCA-CC-PTX (PDCP), mPEG-DCA-SS-PTX (PDSP) and PTX injection to mice at 2 h, 6 h, 12 h, 24 h (n=6), *P<0.05, ***P<0.001.