Doxorubicin-Based Ionic Nanomedicines for Combined Chemo-Phototherapy of Cancer

Abstract

Synergistic combination therapy approach offers lots of options for delivery of materials with anticancer properties, which is a very promising strategy to treat a variety of malignant lesions with enhanced therapeutic efficacy. The current study involves a detailed investigation of combination ionic nanomedicines where a chemotherapeutic drug is coupled with a photothermal agent to attain dual mechanisms (chemotherapy (chemo) and photothermal therapy (PTT)) to improve the drug's efficacy. An FDA-approved Doxorubicin hydrochloride (DOX·HCl) is electrostatically attached with a near-infrared cyanine dye (ICG, IR783, and IR820), which serves as a PTT drug using ionic liquid chemistry to develop three ionic material (IM)-based chemo-PTT drugs. Carrier-free ionic nanomedicines (INMs) are derived from ionic materials (IMs). The photophysical properties of the developed combination IMs and their INMs were studied in depth. The phototherapeutic efficiency of the combination drugs was evaluated by measuring the photothermal conversion efficiency and singlet-oxygen quantum yield. The improved photophysical properties of the combination nanomedicines in comparison to their parent compounds significantly enhanced INMs' photothermal efficiency. Cellular uptake, dark and light toxicity studies, and cell death mechanisms of the chemo-PTT nanoparticles were also studied in vitro. The combination INMs exhibited enhanced cytotoxicity compared to their respective parent compounds. Moreover, the apoptosis cell death mechanism was almost doubled for combination nanomedicine than the free DOX, which is attributed to enhanced cellular uptake. Examination of the combination index and improved in vitro cytotoxicity results revealed a great synergy between chemo and PTT drugs in the developed combination nanomedicines.

Keywords: cell death mechanism; combination therapy; cytotoxicity; doxorubicin; ionic nanomaterial; photothermal therapy.

Figure 1.

(a) Synthesis of ionic material using ion-exchange reaction and (b) ionic nanomaterial synthesis.

Figure 2.

TEM images for (a) [DOX][ICG], (b) [DOX][IR783], and (c) [DOX][IR820] INMs.

Figure 3.

(a) Normalized absorption spectra of DOX and three chemo-PTT combination INMs in water. (b) Fluorescence spectra of NIR dyes and chemo-PTT combination INMs in water at an excitation wavelength of 710 nm.

Figure 4.

Cellular uptake of three ionic nanomaterials in relation to free soluble drugs after 6 h incubation of a 60000 pmol drug in MCF-7 cancer cells. Data are presented as mean ± SD (n = 3). Data are presented as mean SD (n = 3). (*p < 0.05, **p < 0.01, ***p < 0.005).

Figure 5.

(a) Cell viability results for varying concentrations of parent NaICG and doxorubicin-based drugs in MCF-7 cancer cells treated for 24 h in the dark and (b) cell viability results for NaICG and [DOX][ICG] INMs in MCF-7 cancer cells incubated for 6 h in MCF-7 cells and irradiated with 808 nm laser (1 W cm⁻²) for 5 min. Using a two-tailed student’s t test, p-values are determined and are presented as *p < 0.05, **p < 0.01, and ***p < 0.005.

Figure 6.

Confocal microscopy imaging of caspase 3/7 activation on MCF-7 cells incubated with 5 μM DOX and three ionic nanomaterials for 6 h. Scale bar is 10 μm.

Figure 7.

(a–e) YO-PRO/propidium iodide (PI) staining results for MCF-7 cells treated with INMs and DOX after 48 h of drug incubation. Numbers in quadrants show percentages (%) of the total cell populations. (f) Data from flow cytometry experiments are represented here in the form of bar graphs. Error bars are presented as mean ± standard deviation (SD).