Theranostic Pt(IV) Conjugate with Target Selectivity for Androgen Receptor

A dual donor-acceptor fluorescent probe with viscosity response and lipid droplets targeting to initiate oxidative stress for tumor elimination

A dual donor-acceptor photosensitizer TCN-2 prepared based on single donor-acceptor could fulfil lipid droplets targeting to trigger apoptosis and tumor growth arrest. Meanwhile, all of experiments both in phosphate buffer solution and intracellular surroundings have demonstrated that TCN-2 catalyzed the production of type I as well as type II reactive oxygen species, forming a hybrid reactive oxygen species pattern, indicating that TCN-2 could be applied to initiate a series of biological responses triggered by oxidative stress within most high-viscosity solid tumors. In addition, TCN-2 also has the capability of fluorescence imaging, which could perfectly combine therapeutic imaging to achieve therapeutic effects while identifying cancerous lesions. Due to the structural design of double electron-absorbing groups, TCN-2 retained excellent lipophilicity while enhancing solubility in the biological environment. Terrific biocompatibility, minimal phototoxic damage to normal cells and tissues, and specific driving to prescriptive organelles to maximize therapeutic effects were used to enhance the therapeutic effect of photodynamic therapy to cease disease progression.

Umbelliferone and Its Synthetic Derivatives as Suitable Molecules for the Development of Agents with Biological Activities: A Review of Their Pharmacological and Therapeutic Potential

Umbelliferone (UMB), known as 7-hydroxycoumarin, hydrangine, or skimmetine, is a naturally occurring coumarin in the plant kingdom, mainly from the Umbelliferae family that possesses a wide variety of pharmacological properties. In addition, the use of nanoparticles containing umbelliferone may improve anti-inflammatory or anticancer therapy. Also, its derivatives are endowed with great potential for therapeutic applications due to their broad spectrum of biological activities such as anti-inflammatory, antioxidant, neuroprotective, antipsychotic, antiepileptic, antidiabetic, antimicrobial, antiviral, and antiproliferative effects. Moreover, 7-hydroxycoumarin ligands have been implemented to develop 7-hydroxycoumarin-based metal complexes with improved pharmacological activity. Besides therapeutic applications, umbelliferone analogues have been designed as fluorescent probes for the detection of biologically important species, such as enzymes, lysosomes, and endosomes, or for monitoring cell processes and protein functions as well various diseases caused by an excess of hydrogen peroxide. Furthermore, 7-hydroxy-based chemosensors may serve as a highly selective tool for Al3+ and Hg2+ detection in biological systems. This review is devoted to a summary of the research on umbelliferone and its synthetic derivatives in terms of biological and pharmaceutical properties, especially those reported in the literature during the period of 2017-2023. Future potential applications of umbelliferone and its synthetic derivatives are presented.

The role of Platinum(IV)-based antitumor drugs and the anticancer immune response in medicinal inorganic chemistry. A systematic review from 2017 to 2022

Platinum-based antitumor drugs have been used in many types of tumors due to its broad antitumor spectrum in clinic. Encouraged by the cisplatin's (CDDP) worldwide success in cancer chemotherapy, the research in platinum-based antitumor drugs has evolved from traditional platinum drug to multi-ligand and multifunctional platinum prodrugs over half a century. With the rapid development of metal drugs and the anticancer immune response, challenges and opportunities in platinum drug research have been shifted from traditional platinum-based drugs to platinum-based hybrids and the direction of development is tending toward photodynamic therapy, nano-delivery therapy, drug combination, targeted therapy, diagnostic therapy, immune-combination therapy and tumor stem cell therapy. In this review, we first exhaustively overviewed the role of platinum-based antitumor prodrugs and the anticancer immune response in medicinal inorganic chemistry based on the special nanomaterials, the modification of specific ligands, and the multiple functions obtained that are beneficial for tumor therapy in the last five years. We also categorized them according to drug potency and function. There hasn't been a comprehensive evaluation of precursor platinum drugs in prior articles. And a multifarious approach to distinguish and detail the variety of alterations of platinum-based precursors in various valence states also hasn't been summarized. In addition, this review points out the main problems at the interface of chemistry, biology, and medicine from their action mechanisms for current platinum drug development, and provides up-to-date potential strategies from drug design perspectives to circumvent those drawbacks. And a promising idea is also enlightened for researchers in the development and discovery of platinum prodrugs.

Recent Progresses in Conjugation with Bioactive Ligands to Improve the Anticancer Activity of Platinum Compounds

Platinum (Pt) drugs, including cisplatin, are widely used for the treatment of solid tumors. Despite the clinical success, side effects and occurrence of resistance represent major limitations to the use of clinically available Pt drugs. To overcome these problems, a variety of derivatives have been designed and synthetized. Here, we summarize the recent progress in the development of Pt(II) and Pt(IV) complexes with bioactive ligands. The development of Pt(II) and Pt(IV) complexes with targeting molecules, clinically available agents, and other bioactive molecules is an active field of research. Even if none of the reported Pt derivatives has been yet approved for clinical use, many of these compounds exhibit promising anticancer activities with an improved pharmacological profile. Thus, planning hybrid compounds can be considered as a promising approach to improve the available Pt-based anticancer agents and to obtain new molecular tools to deepen the knowledge of cancer progression and drug resistance mechanisms.

Designed, synthesized and biological evaluation of proteolysis targeting chimeras (PROTACs) as AR degraders for prostate cancer treatment

As a continuation of our research on developing potent and potentially safe androgen receptor (AR) degrader, a series of novel proteolysis targeting chimeras (PROTACs) containing the phthalimide degrons with different linker were designed, synthesized and evaluated for their AR degradation activity against LNCaP (AR+) cell line. Most of the synthesized compounds displayed moderate to satisfactory AR binding affinity and might lead to antagonist activity against AR. Among them, compound A16 exhibited the best AR binding affinity (85%) and degradation activity against AR. Due to the strong fluorescence properties of pomalidomide derivatives, B10 was found to be effectively internalized and visualized in LNCaP (AR + ) cells than PC-3 (AR-) cells. Moreover, the molecular docking of A16 with AR and the active site of DDB1-CRBN E3 ubiquitin ligase complex provides guidance to design new PROTAC degrons targeting AR for prostate cancer therapy. These results represent a step toward the development of novel and improved AR PROTACs.

Redirecting Cisplatin and Doxorubicin to Mitochondria Affords Highly Effective PlatinumIV Prodrug Against Triple Negative Breast Cancer

A mitochondria targeting dual-action platinum^IV prodrug exhibits high anticancer activity in triple negative breast cancer cells. The complex intervenes in several cellular processes including DNA damage, perturbation of mitochondrial bioenergetics and induction of necrosis to kill cancer cells.

ASC-J9® suppresses prostate cancer cell proliferation and invasion via altering the ATF3-PTK2 signaling

BACKGROUND

Early studies indicated that ASC-J9®, an androgen receptor (AR) degradation enhancer, could suppress the prostate cancer (PCa) progression. Here we found ASC-J9® could also suppress the PCa progression via an AR-independent mechanism, which might involve modulating the tumor suppressor ATF3 expression.

METHODS

The lentiviral system was used to modify gene expression in C4-2, CWR22Rv1 and PC-3 cells. Western blot and Immunohistochemistry were used to detect protein expression. MTT and Transwell assays were used to test the proliferation and invasion ability.

RESULTS

ASC-J9® can suppress PCa cell proliferation and invasion in both PCa C4-2 and CWR22Rv1 cells via altering the ATF3 expression. Further mechanistic studies reveal that ASC-J9® can increase the ATF3 expression via decreasing Glutamate-cysteine ligase catalytic (GCLC) subunit expression, which can then lead to decrease the PTK2 expression. Human clinical studies further linked the ATF3 expression to the PCa progression. Preclinical studies using in vivo mouse model also proved ASC-J9® could suppress AR-independent PCa cell invasion, which could be reversed after suppressing ATF3.

CONCLUSIONS

ASC-J9® can function via altering ATF3/PTK2 signaling to suppress the PCa progression in an AR-independent manner.

Coumarin-Tagged Dinuclear Trithiolato-Bridged Ruthenium(II)⋅Arene Complexes: Photophysical Properties and Antiparasitic Activity

The synthesis, characterization, photophysical and biological properties of 13 new conjugate coumarin-diruthenium(II)⋅arene complexes against Toxoplasma gondii are presented. For all conjugate organometallic unit/coumarins, an almost complete loss of fluorescence efficacy was observed. However, the nature of the fluorophore, the type of bonding, the presence and length of a linker between the coumarin dye and the ruthenium(II) moiety, and the number of dye units influenced their biological properties. The in vitro activity against a transgenic T. gondii strain grown in human foreskin fibroblasts (HFF) leads to IC50 values for T. gondii β-gal from 105 to 735 nM. Of note is that nine compounds displayed lower IC50 than the standard drug pyrimethamine. One compound applied at its IC50 did not affect B-cell proliferation but had an impact on T-cell proliferation in murine splenocyte cultures. Transmission electron microscopy of T. gondii β-gal-infected HFF showed that treatment predominantly affected the parasites' mitochondrion.

The design, synthesis and anti-tumor mechanism study of new androgen receptor degrader

Targeted protein degradation using small molecules is a novel strategy for drug development. In order to solve the problem of drug resistance in the treatment of prostate cancer, proteolysis-targeting chimeras (PROTAC) was introduced into the design of anti-prostate cancer derivatives. In this work, we synthesized two series of selective androgen receptor degraders (SARDs) containing the hydrophobic degrons with different linker, and then investigated the structure-activity relationships of these hybrid compounds. Most of the synthesized compounds exhibited moderate to good activity against all the cancer cell lines selected. Among them, compound A9 displayed potent inhibitory activity against LNCaP prostate cancer cell line with IC₅₀ values of 1.75 μM, as well as excellent AR degradation activity. Primary mechanism studies elucidated compound A9 arrested cell cycle at G0/G1 phase and induced a mild apoptotic response in LNCaP cells. Further study indicated that the degradation of AR was mediated through proteasome-mediated process. For all these reasons, compound A9 held promising potential as anti-proliferative agent for the development of highly efficient SARDs for drug-resistance prostate cancer therapies.

Multifunctional Pt(iv) complexes containing a glutathione S-transferase inhibitor lead to enhancing anticancer activity and preventing metastasis of osteosarcoma cells

Cisplatin has been clinically applied in the treatment of osteosarcoma (OS), but its efficacy is severely limited due to drug resistance and metastasis. One of the chief culprits is the overexpression of glutathione S-transferases (GSTs) in cancer cells, which can accelerate the interaction of glutathione (GSH) with cisplatin, reducing its biological effects. In this study, three Pt(iv) complexes derived from cisplatin conjugated with a GST inhibitor (NBDHEX) were designed and synthesized. The stabilities and releasing capabilities of these complexes, as well as their abilities to inhibit GSTs, were investigated together with their in vitro anticancer activities toward osteosarcoma cells. Among them, complex 2, bearing one NBDHEX derivative and a hydroxyl group at the axial positions, could markedly kill human OS cells due to its suitable stability and prominent ability to inhibit GSTs. Meanwhile, it can prevent the metastasis of OS via down-regulating Akt. Thus, complex 2 has the potential for further research for the treatment of OS.

Cu-catalyzed N-3-Arylation of Hydantoins Using Diaryliodonium Salts

A general Cu-catalyzed, regioselective method for the N-3-arylation of hydantoins is described. The protocol utilizes aryl(trimethoxyphenyl)iodonium tosylate as the arylating agent in the presence of triethylamine and a catalytic amount of a simple Cu-salt. The method is compatible with structurally diverse hydantoins and operates well with neutral aryl groups or aryl groups bearing weakly donating/withdrawing elements. It is also applicable for the rapid diversification of pharmaceutically relevant hydantoins.

Gd(iii)-Pt(iv) theranostic contrast agents for tandem MR imaging and chemotherapy

Pt(iv) prodrugs have emerged as versatile therapeutics for addressing issues regarding off-target toxicity and the chemoresistance of classic Pt(ii) drugs such as cisplatin and carboplatin. There is significant potential for Pt(iv) complexes to be used as theranostic agents, yet there are currently no reported examples of Gd(iii)–Pt(iv) agents for simultaneous MR imaging and chemotherapy. Here we report the synthesis, characterization, and in vitro efficacy of two Gd(iii)–Pt(iv) agents, GP1 and GP2. Both agents are water soluble and stable under extracellularly relevant conditions but are reduced under intracellular conditions. Both are cytotoxic in multiple cancer cell lines, cell permeable, and significantly enhance the T₁-weighted MR contrast of multiple cell lines. Thus, GP1 and GP2 are promising agents for tandem MR imaging and chemotherapy and provide a versatile platform through which future Gd(iii)–Pt(iv) agents can be developed.

The first example of Gd(iii)–Pt(iv) theranostic agents that are intracellularly reduced to provide MR contrast enhancement with simultaneous Pt(ii) chemotherapy.

Therapeutic potential of coumarin bearing metal complexes: Where are we headed?

The successfully application of some metallodrugs such as salvarsan, silver sulfadiazine and cisplatin in modern medicine launched the biological investigation of organometallic and metal-organic complexes. The availability and tunability of various ligands including N-heterocycles, phosphines, N-heterocyclic carbenes present an extended research area to chemists. In recent years, the preparation of the metal complexes of bioactive organic compounds is a new strategy. Coumarin derivatives are one of the classes of compounds used for this purpose, and many complexes of coumarin derivatives were prepared for enhanced biological activity, especially anticancer and antimicrobial. In this paper, we discuss the current situation of this topic.

Synthesis and evaluation of bi-functional 7-hydroxycoumarin platinum(IV) complexes as antitumor agents

A series of bi-functional 7-hydroxycoumarin platinum(IV) complexes were synthesized, characterized, and evaluated for antitumor activities. The 7-hydroxycoumarin platinum(IV) complexes display moderate to effective antitumor activities toward the tested cell lines and show much potential in overcoming drug resistance of platinum(II) drugs. In reducing microenvironment, the title compounds could be reduced to platinum(II) complex accompanied with two equivalents of coumarin units. By a unique mechanism, the 7-hydroxycoumarin platinum(IV) complex attacks DNA via the released platinum(II) compound, meanwhile it also inhibits the activities of cyclooxygenase by coumarin fragment. This action mechanism might be of much benefit for reducing tumor-related inflammation in the progress of inhibiting tumor proliferation and overcoming cisplatin resistance. The incorporation of 7-hydroxycoumarin leads to significantly enhanced platinum accumulation in both whole tumor cells and DNA. The HSA interaction investigation reveals that the tested coumarin platinum(IV) compound could effectively combine with HSA via van der Waals force and hydrogen bond.

Development of a series of 4-hydroxycoumarin platinum(IV) hybrids as antitumor agents: Synthesis, biological evaluation and action mechanism investigation

A series of new 4-hydroxycoumarin platinum(IV) complexes were designed, synthesized and evaluated as antitumor agents. All the title compounds display moderate to effective antitumor activities toward the tested cell lines and two prominent compounds were screened out with activities comparable to cisplatin and oxaliplatin. The mechanism investigation demonstrates that the platinum(IV) compounds could be reduced to bivalence and exert significant genotoxicity to tumor cells. Meanwhile the coumarin moiety endows the title compounds with cyclooxygenase inhibitory competence which might favour the reduction of tumor-related inflammation and further influence tumor proliferation. The coumarin platinum(IV) complex could effectively induce apoptosis of SKOV-3 cells through up-regulating the expression of caspase3 and caspase9. Furthermore, the conversion of platinum(II) drugs to platinum(IV) form via the conjunction with 4-hydroxycoumarin enhances the drug uptake in whole cells and DNA simultaneously. Moreover, the 4-hydroxycoumarin platinum(IV) complex could combine with human serum albumin via van der Waals force and hydrogen bond, which would influence their transport and bioactivities in vivo.

A cisplatin-based platinum(IV) prodrug containing a glutathione s-transferase inhibitor to reverse cisplatin-resistance in non-small cell lung cancer

A Pt(IV) prodrug of cisplatin containing a glutathione s-transferase (GSTs) inhibitor 6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio)hexanol (NBDHEX), complex 1, was designed and studied aiming to overcome cisplatin-resistance and reduce its toxicity by inhibiting GSTs overexpressed in cancer cells. The complex could be reduced to release its active Pt(II) species and axial ligand in the presence of ascorbic acid. In cytotoxicity study, complex 1 showed more potent anticancer activity than cisplatin and NBDHEX against all the tested cancer cells, especially toward cisplatin resistant A549/DDP cells with a resistance factor value of 0.37. By effectively inhibiting GSTs, complex 1 was found to be able to promote higher platinum uptake and cause more severe DNA damage in both A549 cells and A549/DDP cells as compared with cisplatin. Further mechanism study indicated that it could trigger cell death via an apoptotic pathway. In vivo tests on A549 xenograft tumor mice model showed that complex 1 presented higher tumor inhibiting rate and lower toxicity than cisplatin as well. In all, the Pt(IV) prodrug has potential to be developed as an anticancer agent.

Construction of Dual Stimuli-Responsive Platinum(IV) Hybrids with NQO1 Targeting Ability and Overcoming Cisplatin Resistance

Quinone oxidoreductase isozyme I (NQO1) is a cytoprotective two-electron-specific reductase that highly expresses in various cancer cells. Taking NQO1 as the target, we herein report three hybrid compounds from Pt(IV) complexes and a quinone propionic acid unit. The mechanism studies showed that the hybrids could be activated by both NQO1 and ascorbic acid to release the cytotoxic Pt(II) unit, exhibiting a dual stimuli-responsive character. In the pharmacological studies, complexes 2 and 3 presented higher antitumor activity than cisplatin. More importantly, the hybrid could also overcome cisplatin resistance due to the NQO1 targeting ability, improved cellular uptake, and/or different action mechanism. Significantly, complex 3 containing a coumarin moiety could be effectively activated in NQO1-overexpressed cancer cells to "turn on" fluorescence, showing a promising visual effect in cancer cells. In vivo study revealed that both 2 and 3 exhibited higher antitumor efficacy than cisplatin in the A549 xenograft mouse model at an equimolar dose to cisplatin. In all, the hybrids may serve as promising NQO1-targeting anticancer agents.

Current Developments in Pt(IV) Prodrugs Conjugated with Bioactive Ligands

To overcome the side effects of and resistance to cisplatin, a variety of Pt(IV) prodrugs were designed and synthesized via different modifications including combination with lipid chains to increase hydrophobicity, conjugation with short peptide chains or nanoparticles to improve drug delivery, or addition of bioactive ligands to the axial positions of Pt(IV) complexes to exert dual-function effects. This review summarizes the recent progress in the development of Pt(IV) prodrugs conjugated with bioactive-targeting ligands, including histone deacetylase inhibitors, p53 agonists, alkylating agents, and nonsteroidal anti-inflammatory agents. Although Pt(IV) complexes that conjugated with bioactive ligands show satisfactory anticancer effects, none has been approved for clinical use. Therefore, we hope that this review will contribute to further study and development of Pt(IV) complexes conjugated with bioactive and other ligands.