Chlorin Conjugates in Photodynamic Chemotherapy for Triple-Negative Breast Cancer

Breast cancer (BC) is the most common type of cancer in women and the number of new cases in the US is still increasing each year. Triple-negative breast cancer (TNBC), which comprises 15-20% of all breast cancer, is a heterogeneous disease and is considered the most aggressive type of breast cancer due to the lack of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expressions for treatments. Traditional chemotherapy is the standard protocol for the treatment of TNBC. Toxicity and multidrug resistance are major drawbacks to chemotherapy. The lack of molecular targets and poor prognosis for TNBC prompts an urgent need to discover novel therapeutic strategies to improve clinical outcomes and quality of life for patients. Photodynamic therapy (PDT) or light treatment is a binary anti-cancer procedure that uses a photosensitizer (PS) that, upon light activation, produces cytotoxic oxygen species, destroying tumor cells. PDT is minimally invasive and can be repeated a few times without accumulating significant toxicity in the surrounding tissues. The primary goal of this study was to investigate in vitro photodynamic chemotherapy as a ternary combination therapy using our synthesized photosensitizers (chlorin-vitamin conjugates and their corresponding indium complexes) co-treated with known chemotherapeutic agents (taxol, doxorubicin, cisplatin, fluorouracil, or methotrexate) in the presence of light and determine the optimum conditions as a pre-clinical study of an enhanced tumoricidal effect against TNBC. Our results indicated that the best combination for an effective chemophotodynamic effect involves a ternary treatment of the indium complex of the chlorin-lipoic acid conjugate (InCLA) co-treated with taxol, which exhibited strong synergism at the nanomolar concentration when combined in the presence of visible light irradiation. Other ternary combinations containing taxol with a synergistic anti-tumor effect against TNBC include chlorin-pantothenic acid (CPA) and chlorin-biotin (CBTN) conjugates. Several other ternary combinations containing InCLA, CBTN, and CPA with either cisplatin, fluorouracil, or methotrexate were identified to generate a synergistic or additive effect. The light dosage remained constant, but the dosages of photosensitizers and chemotherapy drugs were varied to obtain the lowest possible concentration for the desired effect. The synergistic, additive or antagonistic effects of the drug combinations were determined based on the Chou-Talalay method, with InCLA-taxol having the lowest combination index (CI) of 0.25. Fluorescence and transmission electron microscopy (TEM) images provided evidence of apoptosis as the preferred mode of cell death. Our study demonstrated the combination of PDT and chemotherapy as a potential treatment option for TNBC patients.

Magnetic Resonance Imaging in Breast Cancer Tissue In Vitro after PDT Therapy

Photodynamic therapy (PDT) is increasingly used in modern medicine. It has found application in the treatment of breast cancer. The most common cancer among women is breast cancer. We collected cancer cells from the breast from the material received after surgery. We focused on tumors that were larger than 10 mm in size. Breast cancer tissues for this quantitative non-contrast magnetic resonance imaging (MRI) study could be seen macroscopically. The current study aimed to present findings on quantitative non-contrast MRI of breast cancer cells post-PDT through the evaluation of relaxation times. The aim of this work was to use and optimize a 1.5 T MRI system. MRI tests were performed using a clinical scanner, namely the OPTIMA MR360 manufactured by General Electric HealthCare. The work included analysis of T1 and T2 relaxation times. This analysis was performed using the MATLAB package (produced by MathWorks). The created application is based on medical MRI images saved in the DICOM3.0 standard. T1 and T2 measurements were subjected to the Shapiro-Wilk test, which showed that both samples belonged to a normal distribution, so a parametric t-test for dependent samples was used to test for between-sample variability. The study included 30 sections tested in 2 stages, with consistent technical parameters. For T1 measurements, 12 scans were performed with varying repetition times (TR) and a constant echo time (TE) of 3 ms. For T2 measurements, 12 scans were performed with a fixed repetition time of 10,000 ms and varying echo times. After treating samples with PpIX disodium salt and bubbling with pure oxygen, PDT irradiation was applied. The cell relaxation time after therapy was significantly shorter than the cell relaxation time before PDT. The cells were exposed to PpIX disodium salt as the administered pharmacological substance. The study showed that the therapy significantly affected tumor cells, which was confirmed by a significant reduction in tumor cell relaxation time on the MRI results.

Synergy between PEDF and Doxorubicin in Breast Cancer Cells: Effects on Metastatic and Metabolic Pathways

Pigment epithelium-derived factor (PEDF), a serine protease inhibitor (Serpin) family member, shows promise in inhibiting tumour growth. In our study, we explored the effects of PEDF on the efficacy of the frontline chemotherapy agent doxorubicin (Dox) in BC cells. We found that Dox+PEDF treatment significantly reduced glucose uptake in MDA-MB-231 cells compared to the control (p = 0.0005), PEDF (p = 0.0137), and Dox (p = 0.0171) alone but paradoxically increased it in MCF-7 cells. Our findings further revealed that PEDF, Dox, and Dox+PEDF substantially hindered tumour cell migration from tumour spheroids, with Dox+PEDF showing the most significant impact (p < 0.0001). We also observed notable decreases in the expression of metastatic markers (uPAR, uPA, CXCR4, MT1-MMP, TNF-α) across all treatment groups (p < 0.0001) in both cell lines. When it comes to metabolic pathways, PEDF increased phosphorylated IRS-1 (p-IRS1) levels in MDA-MB-231 and MCF-7 (p < 0.0001), while Dox decreased it, and the combination led to an increase. In MDA-MB-231 cells, treatment with PEDF, Dox, and the combination led to a notable decrease in both phosphorylated AKT (p-AKT) and total AKT levels. In MCF-7, while PEDF, Dox, and their combination led to a reduction in p-AKT, total levels of AKT increased in the presence of Dox and Dox+PEDF. Combining PEDF with Dox enhances the targeting of metastatic and metabolic pathways in breast cancer cell lines. This synergy, marked by PEDF's increasing roles in cancer control, may pave the way for more effective cancer treatments.

Vesicle-Encapsulated Rolipram (PDE4 Inhibitor) and Its Anticancer Activity

Vesicular carriers of drugs are popular for specific targeting and delivery. The most popular vesicles among these are liposomes. However, they suffer from some inherent limitations. In this work, alternative vesicles with enhanced stability, i.e., niosomes and bilosomes have been prepared, characterized, and their delivery efficiency studied. Bilosomes have the additional advantage of being able to withstand the harsh environment of the gastrointestinal tract (GIT). The taurine-derived bile salt (NaTC) was incorporated into the bilosome bilayer. The inspiration behind NaTC insertion is the recent reports on antiaging action and immune function of taurine. Fluorescence probing was used to study the vesicle environment. The entrapment and subsequent release of the important cAMP-specific PDE4 inhibitor/drug Rolipram, which has antibreast cancer properties, was assessed on the breast cancer cell line MCF-7. Rolipram has important therapeutic applications, one of the most significant in recent times being the treatment of Covid-19-triggered pneumonia and cytokine storms. As for cancer chemotherapy, the localization of drug, targeted delivery, and sustained release are extremely important issues, and it seemed worthwhile to explore the potential of the bilosomes and niosomes to entrap and release Rolipram. The important finding is that niosomes perform much better than bilosomes in the hormone-responsive breast cancer mileau MCF-7. Moreover, there was a 4-fold decrease in the IC50 of Rolipram encapsulated in niosomes compared to Rolipram alone. On the other hand, bilosome-encapsulated Rolipram shows higher IC50 value. The results can be further understood by molecular docking studies.

Pyridoxamine Attenuates Doxorubicin-Induced Cardiomyopathy without Affecting Its Antitumor Effect on Rat Mammary Tumor Cells

Doxorubicin (DOX) is commonly used in cancer treatment but associated with cardiotoxicity. Pyridoxamine (PM), a vitamin B6 derivative, could be a cardioprotectant. This study investigated the effect of PM on DOX cardiotoxicity and DOX antitumor effectiveness. Sprague Dawley rats were treated intravenously with DOX (2 mg/kg/week) or saline over eight weeks. Two other groups received PM via oral intake (1 g/L in water bottles) next to DOX or saline. Echocardiography was performed after eight weeks. PM treatment significantly attenuated the DOX-induced reduction in left ventricular ejection fraction (72 ± 2% vs. 58 ± 3% in DOX; p < 0.001) and increase in left ventricular end-systolic volume (0.24 ± 0.02 µL/cm2 vs. 0.38 ± 0.03 µL/cm2 in DOX; p < 0.0001). Additionally, LA7 tumor cells were exposed to DOX, PM, or DOX and PM for 24 h, 48 h, and 72 h. Cell viability, proliferation, cytotoxicity, and apoptosis were assessed. DOX significantly reduced LA7 cell viability and proliferation (p < 0.0001) and increased cytotoxicity (p < 0.05) and cleaved caspase-3 (p < 0.001). Concomitant PM treatment did not alter the DOX effect on LA7 cells. In conclusion, PM attenuated DOX-induced cardiomyopathy in vivo without affecting the antitumor effect of DOX in vitro, highlighting PM as a promising cardioprotectant for DOX-induced cardiotoxicity.

Cancer treatment therapies: traditional to modern approaches to combat cancers

As far as health issues are concerned, cancer causes one out of every six deaths around the globe. As potent therapeutics are still awaited for the successful treatment of cancer, some unconventional treatments like radiotherapy, surgery, and chemotherapy and some advanced technologies like gene therapy, stem cell therapy, natural antioxidants, targeted therapy, photodynamic therapy, nanoparticles, and precision medicine are available to diagnose and treat cancer. In the present scenario, the prime focus is on developing efficient nanomedicines to treat cancer. Although stem cell therapy has the capability to target primary as well as metastatic cancer foci, it also has the ability to repair and regenerate injured tissues. However, nanoparticles are designed to have such novel therapeutic capabilities. Targeted therapy is also now available to arrest the growth and development of cancer cells without damaging healthy tissues. Another alternative approach in this direction is photodynamic therapy (PDT), which has more potential to treat cancer as it does minimal damage and does not limit other technologies, as in the case of chemotherapy and radiotherapy. The best possible way to treat cancer is by developing novel therapeutics through translational research. In the present scenario, an important event in modern oncology therapy is the shift from an organ-centric paradigm guiding therapy to complete molecular investigations. The lacunae in anticancer therapy may be addressed through the creation of contemporary and pertinent cancer therapeutic techniques. In the meantime, the growth of nanotechnology, material sciences, and biomedical sciences has revealed a wide range of contemporary therapies with intelligent features, adaptable functions, and modification potential. The development of numerous therapeutic techniques for the treatment of cancer is summarized in this article. Additionally, it can serve as a resource for oncology and immunology researchers.

Oleanolic acid increases the anticancer potency of doxorubicin in pancreatic cancer cells

Combination therapy is a novel cancer therapy approach that combines two or more chemotherapy drugs. This treatment modality enhances the efficacy of chemotherapy by targeting key pathways in an additive or synergistic manner. Therefore, we investigated the efficacy of combination therapy by widely used chemotherapy drug doxorubicin (DOX) and oleanolic acid (OA) to induction of apoptosis for pancreatic cancer (PC) therapy. The effects of DOX, OA, and their combination (DOX-OA) were investigated on proliferation and viability of PC cell line (PANC-1) by MTT assay. Moreover, migration and invasion of the cancer cells were evaluated by trans-well migration assay and wound healing assay. Flow cytometry and DAPI (4',6-diamidino-2-phenylindole) staining were employed to investigate apoptosis quantification and qualification of the treated cancer cells. Finally, mRNA expression of apoptosis-related genes was assessed by quantitative real-time polymerase chain reaction. Our results demonstrated that the proliferation and metastasis potential of PC cells significantly decreased after treatment by DOX, OA, and DOX-OA. Moreover, we observed an increase in apoptosis percentage in the treated cancer cells. The apoptosis-related gene expression was modified to increase the apoptosis rate in all of the treatment groups. However, the anticancer potency of DOX-OA combination was significantly more than that of DOX and OA treatments alone. Our study suggested that DOX-OA combination exerts more profound anticancer effects against PC cell lines than DOX or OA monotherapy. This approach may increase the efficiency of chemotherapy and reduce unintended side effects by lowering the prescribed dose of DOX.

Photobiomodulation Improves Anti-Tumor Efficacy of Photodynamic Therapy against Resistant MCF-7 Cancer Cells

Cancer resistance is a primary concern in cancer treatment, and developing an effective modality or strategy to improve therapeutic outcomes is imperative. Photodynamic therapy (PDT) is a treatment modality that targets the tumor with a photoactive molecule and light for the specific destruction of cancer cells. Photobiomodulation (PBM) is a light exposure of cells to energize their biomolecules to respond to therapy. In the present study, we used PBM to mediate and improve the anti-tumor efficacy of zinc phthalocyanine tetrasulfonic acid (ZnPcS4)-PDT on resistant MCF-7 breast cancer cells and explore molecular changes associated with cell death. Different laser irradiation models were used for PBM and PDT combination. The combined treatment demonstrated an additive effect on the viability and Annexin-V/PI-staining cell death assessed through MTT assay and mitochondrial release of cytochrome c. Rhodamine (Rh123) showed increased affinity to mitochondrial disruption of the strategic treatment with PBM and PDT. Results from the autophagy assay indicate an interplay between the mitochondrial and autophagic proteins. These findings were indicative that PBM might improve the anti-tumor of PDT by inducing autophagy in resistant MCF-7 breast cancer cells that evade apoptosis.

Potentiation of novel porphyrin based photodynamic therapy against colon cancer with low dose doxorubicin and elucidating the molecular signalling pathways responsible for relapse

Photodynamic therapy (PDT) is a promising non-invasive treatment modality for cancer and can be potentiated by combination with chemotherapy. Here, we combined PDT of novel porphyrin-based photosensitizers with low dose doxorubicin (Dox) to get maximum outcome. Dox potentiated and showed synergism with PDT under in vitro conditions on CT26.WT cells. The current colon cancer treatment strategies assure partial or even complete tumour regression but loco-regional relapse or distant metastasis is the major cause of death despite combination therapy. The spared cells after the treatment contribute to relapse and it is important to study their behaviour in host environment. Hence, we developed relapse models for PDT, Dox and combination treatments by transplanting respectively treated equal number of live cells to mice (n = 5) for tumour formation. Most of the treated cells lost tumour forming ability, but some treatment resistant cells developed tumours in few mice. These tumours served as relapse models and Western blot analysis of tumour samples provided clinically relevant information to delineate resistance strategies of individual as well as combination therapies at molecular level. Our results showed that low dose Dox helped in increasing the tumour inhibiting effect of PDT in combination therapy, but still there are indeed possibilities of relapse at later stages due to chemoresistance and immune suppression that may occur post-treatment. We observed that the combination therapy may also lead to the development of multidrug resistant (MDR) phenotype during relapse. Thus, this study provided clinically relevant information to further strengthen and improve PDT-drug combination therapy in order to avoid relapse and to treat cancer more effectively.

5-Aminolevulinic Acid-Mediated Photodynamic Therapy Potentiates the Effectiveness of Doxorubicin in Ewing Sarcomas

Ewing sarcomas (ES) are aggressive primary bone tumors that require radical therapy. Promising low toxicity, 5-aminolevulinic acid (5-ALA)-mediated photodynamic therapy (PDT) could enhance the effectiveness of conventional treatment modalities (e.g., doxorubicin (DOX)), improving, thus, the anti-tumorigenic effects. In this study, we investigated the effects of DOX and 5-ALA PDT alone or in combination on three different human ES cell lines. Cell viability, reactive oxygen species (ROS) production, and cellular stiffness were measured 24 h after PDT (blue light-wavelength 436 nm with 5-ALA) with or without DOX. ES cell lines have a different sensitivity to the same doses and exposure of 5-ALA PDT. DOX in combination with 5-ALA PDT was found to be effective in impairing the viability of all ES cells while also increasing cytotoxic activity by high ROS production. The stiffness of the ES cells increased significantly (p < 0.05) post treatment. Overall, our results showed that across multiple ES cell lines, 5-ALA PDT can successfully and safely be combined with DOX to potentiate the therapeutic effect. The 5-ALA PDT has the potential to be a highly effective treatment when used alone or in conjunction with other treatments. More research is needed to assess the effectiveness of 5-ALA PDT in in vivo settings.

In Vitro Cell Death Mechanisms Induced by Dicoma anomala Root Extract in Combination with ZnPcS4 Mediated-Photodynamic Therapy in A549 Lung Cancer Cells

Globally, lung cancer has remained the leading cause of morbidity and mortality in men and women. To enhance photodynamic therapeutic effects in vitro, the present study was designed to reduce dose-dependence in photodynamic therapy (PDT) and evaluate the anticancer effects of Dicoma anomala (D. anomala) root extracts (i.e., chloroform (Chl), ethyl acetate (EtOAc), and methanol (MeOH)) on A549 lung cancer cells. The most active extract of D. anomala (D.A) was used to establish the 50% inhibitory concentration (IC₅₀), which was further used to evaluate the anticancer efficacy of D.A in combination with ZnPcS₄-mediated PDT IC₅₀. The study further evaluated cell death mechanisms by cell viability/ cytotoxicity (LIVE/DEAD^TM assay), flow cytometry (Annexin V-fluorescein isothiocyanate (FITC)-propidium iodide (PI) staining), immunofluorescence (p38, p53, Bax, and caspase 3 expressions), and fluorometric multiplex assay (caspase 8 and 9) 24 h post-treatment with IC₅₀ concentrations of ZnPcS₄-mediated PDT and D.A MeOH root extract. Morphological changes were accompanied by a dose-dependent increase in cytotoxicity, decrease in viability, and proliferation in all experimental models. Apoptosis is the highly favored cell death mechanism observed in combination therapy groups. Apoptotic activities were supported by an increase in the number of dead cells in the LIVE/DEAD^TM assay, and the upregulation of p38, p53, Bax, caspase 3, 8, and 9 apoptotic proteins. In vitro experiments confirmed the cytotoxic and antiproliferative effects of D.A root extracts in monotherapy and in combination with ZnPcS₄-mediated PDT. Taken together, our findings demonstrated that D.A could be a promising therapeutic candidate worth exploring in different types of cancer.

The role of photodynamic therapy in breast cancer - A review of in vitro research

Breast cancer is the most common cancer affecting women and the incidence of occurrence is increasing. Currently, there are many methods of detecting and treating breast cancer. Some treatments have a number of side effects. Photodynamic therapy (PDT) is a minimally invasive method of treatment which uses monochromatic light of low to medium energy to excite previously applied photosensitizers (PS) for ROS production. The purpose of this article is to present a general overview of the use of PDT in in vitro studies of various cancer cell lines. A literature search for articles corresponding to the topic of this review was performed using the PubMed and Scopus databases using the following keywords: 'photodynamic therapy', 'breast cancer', and 'photosensitizer(s).' Much of the reviewed literature is based on evaluations of the cytotoxic potential of various PSs, particularly against the MCF-7 cell line, and enhancement of PDT potential with nanotechnology. Research on photodynamic effects in vitro may be helpful in the pre-clinical search for optimal methods for in vivo clinical treatment.

Synthesis and Photothermal Effects of Intracellular Aggregating Nanodrugs Targeting Nasopharyngeal Carcinoma

Chemotherapy for the treatment of nasopharyngeal carcinoma (NPC) is usually associated with many side effects; therefore, its treatment options have not yet been completely resolved. Improving distribution to the targeted tumor region and enhancing the cellular uptake of drugs can efficiently alleviate the above adverse medical effects. Near-infrared (NIR) laser light-mediated photothermal therapy (PTT) and photodynamic therapy (PDT) are promising strategies for cancer treatment. In the present study, we developed an efficient multifunctional nanocluster with enhanced targeting and aggregation efficiency for PTT and PDT that is composed of a biocompatible folic acid (FA), indocyanine green (ICG) and 2-cyanobenzothiazole (CBT)-functionalized peptide labeled with an aldehyde sodium alginate-modified magnetic iron oxide nanoparticle (ASA-MNP)-based nanocarrier. FA can bind to folate receptors on cancer cell membranes to enhance nanocluster uptake. CBT-modified peptide can react with glutathione (GSH), which is typically present at higher levels in cancer cells, to form intracellular aggregates and increase the local concentration of the nanodrug. In in vitro studies, these nanodrugs displayed the desired uptake capacity by NPC cells and the ability to suppress the growth of cancer cells under laser irradiation. Animal studies validated that these nanodrugs are safe and nontoxic, efficiently accumulate in NPC tumor sites following injection via the caudal vein, and shows superior inhibition of tumor growth in a tumor-bearing mouse model upon near-infrared laser irradiation. The results indicate the potential application of the multifunctional nanoparticles (NPs), which can be used as a new method for the treatment of folate receptor-positive NPC.

Photosensitizing nanoclays for efficient cell uptake and in vitro photodynamic therapy

In this study a straightforward strategy to deliver photosensitizing molecules into cancer cells by using Laponite RD® (LAP) nanodisks as carrier is presented. We report the application of LAP functionalized with a highly hydrophobic Silicon phthalocyanine photosensitizer (SiPc) for efficient cell uptake and photodynamic therapy (PDT) of MCF-7 breast cancer cells in vitro. This inorganic-organic hybrid nanomaterial caused a threefold increase in intracellular ROS levels and 99.7% of cancer cell inactivation after light treatment (630 nm; fluency of 108 J/cm²). With its theranostic capabilities (simultaneous fluorescence and singlet oxygen generation), uptake into cancer cells was monitored to control the photo-inactivation. The functionalized nanodisks already proved to be an efficient photo-inactivator of pathogenic Gram-(+) bacteria and were previously reported as LS10. By extending the use of LS10 to PDT of cancer cells, it is an example of a photosensitizer functionalized nanoclay with multipurpose drug characteristics, demonstrating an intriguing potential for future phototherapeutic studies and applications.

Potential of Cyanine Derived Dyes in Photodynamic Therapy

Photodynamic therapy (PDT) is a method of cancer treatment that leads to the disintegration of cancer cells and has developed significantly in recent years. The clinically used photosensitizers are primarily porphyrin, which absorbs light in the red spectrum and their absorbance maxima are relatively short. This review presents group of compounds and their derivatives that are considered to be potential photosensitizers in PDT. Cyanine dyes are compounds that typically absorb light in the visible to near-infrared-I (NIR-I) spectrum range (750-900 nm). This meta-analysis comprises the current studies on cyanine dye derivatives, such as indocyanine green (so far used solely as a diagnostic agent), heptamethine and pentamethine dyes, squaraine dyes, merocyanines and phthalocyanines. The wide array of the cyanine derivatives arises from their structural modifications (e.g., halogenation, incorporation of metal atoms or organic structures, or synthesis of lactosomes, emulsions or conjugation). All the following modifications aim to increase solubility in aqueous media, enhance phototoxicity, and decrease photobleaching. In addition, the changes introduce new features like pH-sensitivity. The cyanine dyes involved in photodynamic reactions could be incorporated into sets of PDT agents.

Synergistic effect of photodynamic treatment and doxorubicin on triple negative breast cancer cells

Breast cancer is a metastatic cancer that can spread to other organs, such as the bone, liver, and brain. There are many treatments for breast cancer, such as surgery and chemotherapy, but they lead to resistance and side effects. Therefore, the discovery of new therapies with high efficacy and low toxicity that selectively affect cancer cells is of great importance. Of late, the combination therapy has been suggested as a novel approach compared to existing treatments. In the present study, the effect of the combined treatment of doxorubicin (DOX) and methylene blue activated in the presence of laser irradiation (PDT) on triple-negative breast cancer cells has been investigated. Human breast cancer cell line MDA-MB-231 was exposed to different concentrations of DOX, methylene blue (MB) and DOX-methylene blue (MB-DOX) combination therapy in two different conditions: first the treatment with DOX and then with MB-PDT, and another treatment first with MB-PDT and then with DOX. Cell viability was evaluated using the MTT assay. Morphological and colonization changes were observed by light microscopy. The occurrence of apoptotic cell death was assessed by double-staining ethidium bromide-acridine orange using fluorescence microscopy and flow cytometry. The results showed that the combination of using MB-PDT, followed by DOX (even at low concentrations), has a better effect on inducing cancer cell death in comparison to DOX alone. The result of this study suggests that the combination therapy of MB-PDT-DOX can be used as a potential strategy for the treatment of triple-negative breast cancer cells.

Study of Cytotoxic and Photodynamic Activities of Dyads Composed of a Zinc Phthalocyanine Appended to an Organotin

The combination of photodynamic therapy and chemotherapy is a promising strategy to enhance cancer therapeutic efficacy and reduce drug resistance. In this study two zinc(II) phthalocyanine-tin(IV) conjugates linked by a triethylene glycol chain were synthesized and characterized. In these complexes, the zinc(II) phthalocyanine was used as a potential photosensitizer for PDT and the tin complex was selected as cytostatic moiety. The two dyads composed of zinc(II) phthalocyanine and tin complexes exhibited high cytotoxicity, in absence of light stimulation, against MCF-7 human breast cancer cells with low LC₅₀ values in the range of 0.016–0.453 µM. In addition, these complexes showed superior cytotoxicity than their mixture of equimolar component, accompanied with a higher activity towards cancer cells compared to human healthy fibroblasts. However, under irradiation of the zinc phthalocyanine unit (at 650 nm) no photodynamic activity could be detected, due to the most likely quenching of zinc(II) phthalocyanine singlet excited state by the nearby tin complex according to a photoinduced electron transfer process. This study demonstrates the potential of heterometallic anticancer chemotherapeutics composed of a zinc phthalocyanine and tin complex, and it highlights that the development of such conjugates requires that the sensitizer preserves its photophysical properties and in particular its singlet oxygen sensitization ability in the conjugate in order to combine the PDT activity with the cytotoxicity of the anticancer drug.

Synthesis, characterization, photophysics, and photochemistry of peripherally substituted tetrakis(quinolinylethylenephenoxy)-substituted zinc(ii) phthalocyanines

Quinoline substituted zinc phthalocyanine derivatives were synthesized and characterized, and their photophysical and photochemical properties were investigated.

In vitro irradiation of doxorubicin with 18F-FDG Cerenkov radiation and its potential application as a theragnostic system

Doxorubicin (DOX), an effective chemotherapeutic agent, has a wide excitation band centred at 480 nm. Cerenkov radiation (CR) is considered an internal light source in photodynamic therapy (PDT). DOX could be photoactivated by CR and thus, enhancing its cytotoxicity. In this work, ¹⁸F-FDG was used to evaluate the effect of Cerenkov radiation on DOX, in comparison to irradiation with a 450-nm laser beam, in terms of ROS production. The production of ¹O₂ and O₂^⁎- reactive species during DOX irradiation was detected indirectly by ABMA and DCPIP bleaching, respectively. The cytotoxic effect of the DOX / ¹⁸F-FDG CR system was evaluated in the T47D breast cancer cell line. The irradiation of DOX produced ¹O₂ and O₂^⁎- species using both ¹⁸F-FDG CR and a 450-nm laser beam. The majority reactive species produced in both cases was ¹O₂; a favourable result, given the greater cytotoxicity of this species. The viability of T47D cells in presence of DOX (5 nM), ¹⁸F-FDG (37.5 μCi) and DOX (5 nM)/¹⁸F-FDG (37.5 μCi) was (86 ± 9)%, (84 ± 8)% and (64 ± 5)%, respectively; these results suggest a synergistic cytotoxic effect derived from the cytotoxic activity of DOX and its photoactivation by ¹⁸F-FDG CR. It is worth noting that the system could be optimized in terms of DOX concentration and ¹⁸F-FDG activity for better results. Due to the fact that ¹⁸F-FDG is widely used in nuclear imaging, the DOX/¹⁸F-FDG system also possesses theragnostic characteristics. Thus, in this work, it is demonstrated that DOX can be used in a dual therapy system based on chemotherapy-PDT when ¹⁸F-FDG CR is used as a DOX excitation source.

Phototoxic effectiveness of zinc phthalocyanine tetrasulfonic acid on MCF-7 cells with overexpressed P-glycoprotein

The development of multidrug resistance is often associated with the over-expression of P-glycoprotein (P-gp). This protein prevents drug accumulation and extrudes them out of the cell before they reach the intended target. The aim of this study was to develop an in vitro MCF-7 cell line with increased expression of P-gp and test the phototoxicity of a novel photoactivated zinc phthalocyanine tetrasulfonic acid (ZnPcS4) on these cells. The over-expressed P-gp MCF-7 cells (MCF-7/DOX) were developed from wildtype (WT) MCF-7 cells by a stepwise continuous exposure of the WT cells to different concentrations of Doxorubicin (DOX) (0.1 - 1 μM) over a period of 4 months. The P-gp expression was measured using flow cytometry, immunofluorescence and enzyme immunoassay. To verify whether zinc phthalocyanine-mediated photodynamic therapy (ZnPcS4 - PDT) is effective in MCF-7/DOX, we studied the subcellular localization, phototoxicity and nuclear damage. The flow cytometry result showed two distinct peaks of P-gp positive and negative expression in MCF-7/DOX cell population, which correlates with the ELISA-based assay (p˂0.001). The ME16C (Normal breast cells) was used as control. The localization studies showed that ZnPcS4 have greater affinity for lysosome than mitochondria. Phototoxicity results indicated that photoactivated zinc phthalocyanine decreased the cell proliferation and viability as the drug and laser light dosages increased to 16 μM and 20 J/cm² respectively. PDT-induced cytotoxicity using lactose dehydrogenase (LDH) enzyme leakage as measure did not increase likewise. The ZnPcS4-induced PDT was less effective for MCF-7/DOX cells which could be attributed to decreased retention of ZnPcS4 in major cellular organelles due to the presence of increased drug efflux P-gp. The current findings suggest that, increased P-gp expression, a characteristic of multidrug resistance together with other related intrinsic mechanisms might contribute to render MCF-7/DOX cells less sensitive to ZnPcS4-induced phototoxicity.

Synergy of Chemo- and Photodynamic Therapies with C60 Fullerene-Doxorubicin Nanocomplex

A nanosized drug complex was explored to improve the efficiency of cancer chemotherapy, complementing it with nanodelivery and photodynamic therapy. For this, nanomolar amounts of a non-covalent nanocomplex of Doxorubicin (Dox) with carbon nanoparticle C60 fullerene (C60) were applied in 1:1 and 2:1 molar ratio, exploiting C60 both as a drug-carrier and as a photosensitizer. The fluorescence microscopy analysis of human leukemic CCRF-CEM cells, in vitro cancer model, treated with nanocomplexes showed Dox's nuclear and C60's extranuclear localization. It gave an opportunity to realize a double hit strategy against cancer cells based on Dox's antiproliferative activity and C60's photoinduced pro-oxidant activity. When cells were treated with 2:1 C60-Dox and irradiated at 405 nm the high cytotoxicity of photo-irradiated C60-Dox enabled a nanomolar concentration of Dox and C60 to efficiently kill cancer cells in vitro. The high pro-oxidant and pro-apoptotic efficiency decreased IC50 16, 9 and 7 × 103-fold, if compared with the action of Dox, non-irradiated nanocomplex, and C60's photodynamic effect, correspondingly. Hereafter, a strong synergy of therapy arising from the combination of C60-mediated Dox delivery and C60 photoexcitation was revealed. Our data indicate that a combination of chemo- and photodynamic therapies with C60-Dox nanoformulation provides a promising synergetic approach for cancer treatment.