Synthesis and biological evaluation of nandrolone-bodipy conjugates

Cytotoxicity of Amino-BODIPY Modulated via Conjugation with 2-Phenyl-3-Hydroxy-4(1H)-Quinolinones

The combination of cytotoxic amino-BODIPY dye and 2-phenyl-3-hydroxy-4(1H)-quinolinone (3-HQ) derivatives into one molecule gave rise to selective activity against lymphoblastic or myeloid leukemia and the simultaneous disappearance of the cytotoxicity against normal cells. Both species' conjugation can be realized via a disulfide linker cleavable in the presence of glutathione characteristic for cancer cells. The cleavage liberating the free amino-BODIPY dye and 3-HQ derivative can be monitored by ratiometric fluorescence or by the OFF-ON effect of the amino-BODIPY dye. A similar cytotoxic activity is observed when the amino-BODIPY dye and 3-HQ derivative are connected through a non-cleavable maleimide linker. The work reports the synthesis of several conjugates, the study of their cleavage inside cells, and cytotoxic screening.

Photodynamic and Cold Atmospheric Plasma Combination Therapy Using Polymeric Nanoparticles for the Synergistic Treatment of Cervical Cancer

Integrating multi-modal therapies into one platform could show great promise in overcoming the drawbacks of conventional single-modal therapy and achieving improved therapeutic efficacy in cancer. In this study, we prepared pheophorbide a (Pheo a)/targeting ligand (epitope analog of oncoprotein E7, EAE7)-conjugated poly(γ-glutamic acid) (γ-PGA)/poly(lactide-co-glycolide)-block-poly(ethylene glycol) methyl ether (MPEG-PLGA)/hyaluronic acid (PPHE) polymeric nanoparticles via self-assembly and encapsulation method for the photodynamic therapy (PDT)/cold atmospheric plasma (CAP) combinatory treatment of human papillomavirus (HPV)-positive cervical cancer, thereby enhancing the therapeutic efficacy. The synthesized PPHE polymeric nanoparticles exhibited a quasi-spherical shape with an average diameter of 80.5 ± 17.6 nm in an aqueous solution. The results from the in vitro PDT efficacy assays demonstrated that PPHE has a superior PDT activity on CaSki cells due to the enhanced targeting ability. In addition, the PDT/CAP combinatory treatment more effectively inhibited the growth of cervical cancer cells by causing elevated intracellular reactive oxygen species generation and apoptotic cell death. Moreover, the three-dimensional cell culture model clearly confirmed the synergistic therapeutic efficacy of the PDT and the CAP combination therapy using PPHE on CaSki cells. Overall, these results indicate that the PDT/CAP combinatory treatment using PPHE is a highly effective new therapeutic modality for cervical cancer.

Oxime-based 19-nortestosterone-pheophorbide a conjugate: bimodal controlled release concept for PDT

Photodynamic therapy has become a feasible direction for the treatment of both malignant and non-malignant diseases. It has been in the spotlight since FDA regulatory approval was granted to several photosensitizers worldwide. Nevertheless, there are still strong limitations in the targeting specificity that is vital to prevent systemic toxicity. Here, we report the synthesis and biological evaluation of a novel bimodal oxime conjugate composed of a photosensitizing drug, red-emitting pheophorbide a, and nandrolone (NT), a steroid specifically binding the androgen receptor (AR) commonly overexpressed in various tumors. We characterized the physico-chemical properties of the NT-pheophorbide a conjugate (NT-Pba) and singlet oxygen generation. Because light-triggered therapies have the potential to provide important advances in the treatment of hormone-sensitive cancer, the biological potential of this novel specifically-targeted photosensitizer was assessed in prostatic cancer cell lines in vitro using an AR-positive (LNCaP) and an AR-negative/positive cell line (PC-3). U-2 OS cells, both with and without stable AR expression, were used as a second cell line model. Interestingly, we found that the NT-Pba conjugate was not only photodynamically active and AR-specific, but also that its phototoxic effect was more pronounced compared to pristine pheophorbide a. We also examined the intracellular localization of NT-Pba. Live-cell fluorescence microscopy provided clear evidence that the NT-Pba conjugate localized in the endoplasmic reticulum and mitochondria. Moreover, we performed a competitive localization study with the excess of nonfluorescent NT, which was able to displace fluorescent NT-Pba from the cell interior, thereby further confirming the binding specificity. The oxime ether bond degradation was assayed in living cells by both real-time microscopy and a steroid receptor reporter assay using AR U-2 OS cells. Thus, NT-Pba is a promising candidate for both the selective targeting and eradication of AR-positive malignant cells by photodynamic therapy.

Gold(i)-BODIPY-imidazole bimetallic complexes as new potential anti-inflammatory and anticancer trackable agents

Two new gold(i)-BODIPY-imidazole based trackable therapeutic bimetallic complexes have been synthesized and fully characterized. They display strong antiproliferative properties on several types of cancers including colon, breast, and prostate and one of them presents a significant anti-inflammatory effect. Additionally, the two compounds could be visualised in vitro by confocal microscopy in the submicromolar range.

Synthesis of Novel C-2- or C-15-Labeled BODIPY-Estrone Conjugates

Novel BODIPY-estrone conjugates were synthesized via Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC). Estrone-alkynes or an estrone-azide as starting compounds were synthesized via Michael addition or Sonogashira reaction as key steps. Fluorescent dyes based on BODIPY-core were provided by azide or alkyne functional groups. Fluorescent labeling of estrone was efficiently achieved at the C-2 or C-15 position. The newly-elaborated coupling procedures might have a broad applicability in the synthesis of fluorescent-labeled estrone conjugates suitable for biological assays.

BODIPY-based fluorescent liposomes with sesquiterpene lactone trilobolide

Like thapsigargin, which is undergoing clinical trials, trilobolide is a natural product with promising anticancer and anti-inflammatory properties. Similar to thapsigargin, it has limited aqueous solubility that strongly reduces its potential medicinal applications. The targeted delivery of hydrophobic drugs can be achieved using liposome-based carriers. Therefore, we designed a traceable liposomal drug delivery system for trilobolide. The fluorescent green-emitting dye BODIPY, cholesterol and trilobolide were used to create construct 6. The liposomes were composed of dipalmitoyl-3-trimethylammoniumpropane and phosphatidylethanolamine. The whole system was characterized by atomic force microscopy, the average size of the liposomes was 150 nm in width and 30 nm in height. We evaluated the biological activity of construct 6 and its liposomal formulation, both of which showed immunomodulatory properties in primary rat macrophages. The uptake and intracellular distribution of construct 6 and its liposomal formulation was monitored by means of live-cell fluorescence microscopy in two cancer cell lines. The encapsulation of construct 6 into the liposomes improved the drug distribution in cancer cells and was followed by cell death. This new liposomal trilobolide derivative not only retains the biological properties of pure trilobolide, but also enhances the bioavailability, and thus has potential for the use in theranostic applications.

BODIPY–steroid conjugates: Syntheses and biological applications

BODIPY and aza-BODIPY fluorophores linked to steroids are being developed as multimodal-imaging agents to monitor the mechanism of action of biologically active components in living systems.

Stereocontrolled synthesis of the four 16-hydroxymethyl-19-nortestosterone isomers and their antiproliferative activities

Novel 16-hydroxymethyl-19-nortestosterone diastereomers were prepared by Birch reduction from the corresponding 3-methoxy-16-hydroxymethylestra-1,3,5(10)-trien-17-ol isomers with known configurations. The synthesized compounds are 16α- and 16β-hydroxymethyl-substituted 19-nortestosterone and their 17α-epimers. To prepare 17α-19-nortestosterone, the Mitsunobu inversion reaction of 19-nortestosterone with different alkyl and aryl carboxylic acids was chosen. Deacylation of the new compounds by the Zemplén method yielded the required 17α-19-nortestosterone. The antiproliferative activities of the structurally related compounds were determined in vitro through microculture tetrazolium assays on a panel of human adherent cervical (HeLa, SiHa and C33A), breast (MCF-7, MDA-MB-231, MDA-MB-361 and T47D) and ovarian (A2780) cell lines. The 17α epimer of 19-nortestosterone demonstrated considerable activity, selectively for HeLa cells, with a calculated IC50 of 0.65 μM. The reference compound, cisplatin, displayed an order of magnitude higher IC50 (12.4 μM). The cancer selectivity of 17α-19-nortestosterone was tested by MTT assay performed with noncancerous human fibroblast cell line MRC-5. The results indicated that 17α-19-nortestosterone selectively disturbs the viability of HeLa cells without greatly affecting other cancer cell types and intact fibroblasts.

Brassinosteroid-BODIPY conjugates: Design, synthesis, and properties

Three BS-BODIPY (brassinosteroids-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) conjugates were synthesized and their fluorescent and immunological properties were investigated. Two of the conjugates, having present all the functional groups characteristic of BS, were shown to be potentially useful as biological probes to study involvement of BS into physiological processes in living cells.