Synthesis of asymmetric zinc(II) phthalocyanines with two different functional groups & spectroscopic properties and photodynamic activity for photodynamic therapy

Engineered protein cages with enhanced extracellular drug release for elevated antitumor efficacy

Human heavy chain ferritin (HFn) protein cage has been explored as a nanocarrier for targeted anticancer drug delivery. Here, we introduced a matrix metalloproteinases (MMPs)-cleavable sequence into the DE loop of HFn, creating an MMP-responsive variant, MR-HFn, for localized and extracellular drug release. The crystal structure of MR-HFn revealed that the addition of the MMPs recognition sequence did not affect the self-assembly of HFn but presented a surface-exposed loop susceptible to MMPs cleavage. Biochemical analysis indicated that this engineered protein cage is responsive to MMPs, enabling the targeted release of encapsulated drugs. To evaluate the therapeutic potential of this engineered protein cage, monosubstituted β-carboxy phthalocyanine zinc (CPZ), a type of photosensitizer, was loaded inside this protein cage. The prepared CPZ@MR-HFn showed higher uptake and stronger phototoxicity in MMPs overexpressed tumor cells, as well as enhanced penetration into multicellular tumor spheroids compared with its counterpart CPZ@HFn in vitro. In vivo, CPZ@MR-HFn displayed a higher tumor inhibitory rate than CPZ@HFn under illumination. These results indicated that MR-HFn is a promising nanocarrier for anticancer drug delivery and the MMP-responsive strategy here can also be adapted for other stimuli.

Low-Dose Near-Infrared Light-Activated Mitochondria-Targeting Photosensitizers for PDT Cancer Therapy

Phthalocyanines (Pcs) are promising candidates for photodynamic therapy (PDT) due to their absorption in the phototherapeutic window. However, the highly aromatic Pc core leads to undesired aggregation and decreased reactive oxygen species (ROS) production. Therefore, short PEG chain functionalized A₃B type asymmetric Pc photosensitizers (PSs) were designed in order to decrease aggregation and increase the aqueous solubility. Here we report the synthesis, characterization, optical properties, cellular localization, and cytotoxicity of three novel Pc-based agents (LC31, MLC31, and DMLC31Pt). The stepwise functionalization of the peripheral moieties has a strong effect on the distribution coefficient (logP), cellular uptake, and localization, as well as photocytotoxicity. Additional experiments have revealed that the presence of the malonic ester moiety in the reported agent series is indispensable in order to induce photocytotoxicity. The best-performing agent, MLC31, showed mitochondrial targeting and an impressive phototoxic index (p.i.) of 748 in the cisplatin-resistant A2780/CP70 cell line, after a low-dose irradiation of 6.95 J/cm². This is the result of a high photocytotoxicity (IC₅₀ = 157 nM) upon irradiation with near-infrared (NIR) light, and virtually no toxicity in the dark (IC₅₀ = 117 μM). Photocytotoxicity was subsequently determined under hypoxic conditions. Additionally, a preliminarily pathway investigation of the mitochondrial membrane potential (MMP) disruption and induction of apoptosis by MLC31 was carried out. Our results underline how agent design involving both hydrophilic and lipophilic peripheral groups may serve as an effective way to improve the PDT efficiency of highly aromatic PSs for NIR light-mediated cancer therapy.

Docetaxel-Loaded Novel Nano-Platform for Synergistic Therapy of Non-Small Cell Lung Cancer

Nowadays, non-small cell lung cancer (NSCLC) is threatening the health of all mankind. Although many progresses on treatment of lung cancer have been achieved in the past few decades, the current treatment methods are still traditional surgery, radiotherapy, and chemotherapy, which had poor selectivity and side effects. Lower-toxicity and more efficient treatments are in sore need. In this paper, a smart nanodelivery platform based on photothermal therapy, chemotherapy, and immunotherapy was constructed. The nanoparticles are composed of novel photothermal agents, Mn-modified phthalocyanine derivative (Mn^IIIPC), docetaxel (DTX), and an effective targeting molecule, hyaluronic acid. The nanoplatform could release Mn²⁺ from Mn^IIIPC@DTX@PLGA@Mn²⁺@HA(MDPMH) and probably activate tumor immunity through cGAS-STING and chemotherapy, respectively. Furthermore, DTX could be released in the process for removal of tumor cells. The “one-for-all” nanomaterial may shed some light on treating NSCLC in multiple methods.

Phthalocyanine and Its Formulations: A Promising Photosensitizer for Cervical Cancer Phototherapy

Cervical cancer is one of the most common causes of cancer-related deaths in women worldwide. Despite advances in current therapies, women with advanced or recurrent disease present poor prognosis. Photodynamic therapy (PDT) has emerged as an effective therapeutic alternative to treat oncological diseases such as cervical cancer. Phthalocyanines (Pcs) are considered good photosensitizers (PS) for PDT, although most of them present high levels of aggregation and are lipophilic. Despite many investigations and encouraging results, Pcs have not been approved as PS for PDT of invasive cervical cancer yet. This review presents an overview on the pathophysiology of cervical cancer and summarizes the most recent developments on the physicochemical properties of Pcs and biological results obtained both in vitro in tumor-bearing mice and in clinical tests reported in the last five years. Current evidence indicates that Pcs have potential as pharmaceutical agents for anti-cervical cancer therapy. The authors firmly believe that Pc-based formulations could emerge as a privileged scaffold for the establishment of lead compounds for PDT against different types of cervical cancer.

Design, synthesis and biological evaluation of water soluble and non-aggregated silicon phthalocyanines, naphthalocyanines against A549, SNU-398, SK-MEL128, DU-145, BT-20 and HFC cell lines as potential anticancer agents

Cancer has become an important public problem in worldwide since cancer incidence and mortality are growing rapidly. In this study, water soluble and non-aggregated silicon (IV) phthalocyanines and naphthalocyanines containing (3,5-bis{3-[3-(diethylamino)phenoxy]propoxy}phenyl)methoxy groups have been synthesized and characterized to investigate their anticancer potential. Their DNA binding/nuclease, topoisomerases inhibition were investigated using UV-Vis absorption, thermal denaturation and agarose gel electrophoresis. The in vitro cytotoxic properties of the compounds on human lung (A549), breast (BT-20), liver (SNU-398), prostate (DU-145), melanoma (SK-Mel 128) carcinoma and human fibroblast (HFC) normal cell lines were evaluated by using MTT assay. In order to determine the mechanism of cancer cell growth suppression, cell cycle analysis was carried out using flow cytometer on A549 cell line. The K_b values of SiPc1a and SiNc2a were 6.85 ± (0.35) × 10⁶ and 1.72 ± (0.16) × 10⁴ M^-1 and T_m values of ct-DNA were calculated as 82.02 °C and 78.07 °C, respectively in the presence of both compounds. The Δ_Tm values of SiPc1a and SiNc2a were calculated as 6.45 and 2.50 °C, respectively. The nuclease effects of SiPc1a and SiNc2a with supercoiled plasmid pBR322 DNA demonstrated that both compounds did not trigger any DNA nuclease effects at the lowest concentrations without irradiation whereas both compounds in the presence of activating agent (H₂O₂) showed significant plasmid DNA nuclease actions under irradiation (22.5 J/cm²). SiPc1a and SiNc2a inhibited to topoisomerase I on increasing concentrations whilst they had lower inhibition action toward topoisomerase II that of topoisomerase I. The in vitro cytotoxicity studies displayed that SiPc1a had the highest cytotoxic effects among the tested compounds against A549, SNU-398, SK-MEL128, DU-145, BT-20 and HFC cell lines with CC₅₀ values ranged from 0.49 to 2.99 µM. Furthermore, SiPc1a inhibited cell proliferation by cell cycle arrest in G₀/G₁ phase. All of these results suggested that SiPc1a is a promising candidate as an anticancer agent.

Improved targeting for photodynamic therapy via a biotin–phthalocyanine conjugate: synthesis, photophysical and photochemical measurements, and in vitro cytotoxicity assay

In this study, the peripherally biotin-substituted zinc(ii) phthalocyanine (Pc2) was synthesized as a photosensitizer for the treatment of cancer by photodynamic therapy.

Biotinylated-cationic zinc(II) phthalocyanine towards photodynamic therapy

Targeting biotin receptors in cancer cells can improve specifying of photosensitizers (PSs) for cancer treatment by photodynamic therapy (PDT) applications. Consequently, there has been extensive research focusing mainly on the design of PSs with optimized pharmaceutical properties and better targeting toward cancer cells. Herein a tailored mono-biotinylated zinc(II) phthalocyanine (Pc-1) substituted with six phenoxy-bis(triazolyl) substituents has been synthesized. This Pc-1 has been further modified to its cationic version (Pc-2) through quaternizing of the triazole moiety to gain water solubility. Both non-ionic zinc(II) phthalocyanine (Pc-1) and its cationic derivative (Pc-2) were characterized by standard spectroscopic techniques, namely; FT-IR, 1H and [Formula: see text]C NMR, UV-Vis and MALDI-TOF, and by elemental analysis. The photophysical and photochemical properties were evaluated in DMSO for the non-ionic Pc-1 and in both DMSO and water for the cationic Pc-2.

Synthesis and investigation of phthalocyanine-biotin conjugates

An isothiocyanato-functionalized phthalocyanine (Pc) was synthesized in good yield from the corresponding amine-substituted Pc. This Pc reacted with ethanolamine, biotin hydrazine, and biotin diethylamine under mild conditions (room temperature in DMF or DMSO in the presence of TEA) to produce the corresponding thiourea products in 60-75% yields. All Pcs showed intense Q absorptions in DMF around 677 nm, emissions centered at 683 nm, and fluorescence quantum yields in the range 0.18-0.27. The Pcs were phototoxic to human carcinoma HEp2 cells (IC50 ~ 7 at 1.5 J/cm2) and localized in multiple organelles, including the lysosomes, Golgi and ER. One biotin-Pc conjugate was injected via tail vein into nude mice bearing HT-29 tumors and demonstrated selective localization in the tumor tissue.

Recent advances in chemistry of phthalocyanines bearing electron-withdrawing halogen, nitro and N-substituted imide functional groups and prospects for their practical application

Herein, we present an overview of the approaches for the synthesis of phthalocyanines bearing electron-withdrawing halogen-, nitro- and N-substituted imide functional groups in different positions of the phthalocyanine macrocycle.

Tumour-targeting photosensitisers for one- and two-photon activated photodynamic therapy

Efficient receptor-mediated delivery of a folate-targeted photosensitiser to kill cancer cells following two-photon excitation in the near-infrared is demonstrated.

Improved photodynamic efficacy of thiophenyl sulfonated zinc phthalocyanine loaded in lipid nano-carriers for hepatocellular carcinoma cancer cells

BACKGROUND

The aim of the present study was to modify the structural activity of zinc(II)phthalocyanine by combining it with thiophenyl groups then loaded in lipid nano-carriers and evaluate its parameters required for the structure-activity relationship (SAR) for photodynamic therapy (PDT) of cancer.

METHODS

Tetra (4-Thiophenyl) sulfonated phthalocyaninatozinc(II) (PhS·SO₃Na)₄ZnPc 5 was synthesized and characterized by various spectroscopic methods as a test compound. Liver hepatocellular carcinoma (HepG2) cells were treated with the synthesized (PhS·SO₃Na)₄ZnPc 5 derivative loaded in lipid nano carriers to understand the effect of combined compound on liver cancer cells. Furthermore, HepG2 cells were irradiated by visible red light at 60 mW/cm² for 20 min. The phototoxicity of (PhS·SO₃Na)₄ZnPc 5 after being formulated in both (L) and transfersomes (T) was investigated.

RESULTS

Overall, the results indicate that combination of thiophenyl groups substitution, in particular in the structure of sulfonated zinc phthalocyanine is able to improve the photodynamic properties of ZnPc, and (PhS·SO₃Na)₄ZnPc 5 loaded in lipid nano-carriers can be a promising combined PDT treatment strategy for Liver hepatocellular carcinoma (HepG2) cells.

CONCLUSIONS

The new formulation ZnPc-lipid nano-carriers will be beneficial in the upcoming clinical trials and would enhance the inhibition of tumor growth.

Photochemical property of a Ru(ii) compound based on 3-(2-pyridyl)pyrazole and 2,2′-bipyridine for ablation of cancer cells

Ru(ii) compounds are potential candidates for photodynamic therapy (PDT).

A Molecular Combination of Zinc(II) Phthalocyanine and Tamoxifen Derivative for Dual Targeting Photodynamic Therapy and Hormone Therapy

The combination of photodynamic therapy and other cancer treatment modalities is a promising strategy to enhance therapeutic efficacy and reduce side effects. In this study, a tamoxifen-zinc(II) phthalocyanine conjugate linked by a triethylene glycol chain has been synthesized and characterized. Having tamoxifen as the targeting moiety, the conjugate shows high specific affinity to MCF-7 breast cancer cells overexpressed estrogen receptors (ERs) and tumor tissues, therefore leading to a cytotoxic effect in the dark due to the cytostatic tamoxifen moiety, and a high photocytotoxicity due to the photosensitizing phthalocyanine unit against the MCF-7 cancer cells. The high photodynamic activity of the conjugate can be attributed to its high cellular uptake and efficiency in generating intracellular reactive oxygen species. Upon addition of exogenous 17β-estradiol as an ER inhibitor, the cellular uptake and photocytotoxicity of the conjugate are reduced significantly. As shown by confocal microscopy, the conjugate is preferentially localized in the lysosomes of the MCF-7 cells.

Preparation and In Vitro Photodynamic Activity of Glucosylated Zinc(II) Phthalocyanines as Underlying Targeting Photosensitizers

Two novel glucosylated zinc(II) phthalocyanines 7a–7b, as well as the acetyl-protected counterparts 6a–6b, have been synthesized by the Cu(I)-catalyzed 1,3-dipolar cycloaddition between the propargylated phthalocyanine and azide-substituted glucoses. All of these phthalocyanines were characterized with various spectroscopic methods and studied for their photo-physical, photo-chemical, and photo-biological properties. With glucose as the targeting unit, phthalocyanines 7a–7b exhibit a specific affinity to MCF-7 breast cancer cells over human embryonic lung fibroblast (HELF) cells, showing higher cellular uptake. Upon illumination, both photosensitizers show high cytotoxicity with IC₅₀ as low as 0.032 µM toward MCF-7 cells, which are attributed to their high cellular uptake and low aggregation tendency in the biological media, promoting the generation of intracellular reactive oxygen species (ROS). Confocal laser fluorescence microscopic studies have also revealed that they have high and selective affinities to the lysosomes, but not the mitochondria, of MCF-7 cells. The results show that these two glucosylated zinc(II) phthalocyanines are potential anticancer agents for targeting photodynamic therapy.