Synthesis and biological evaluation of naphthalimide-polyamine conjugates modified by alkylation as anticancer agents through p53 pathway

Synthesis and evaluation of a 68Ga-labeled spermine derivative for tumor PET imaging

BACKGROUND

The polyamine transporter system (PTS), which renders it a promising target for tumor therapy and imaging applications, facilitates the transmembrane transport of polyamines. We reported a novel derivative of spermine labeled with gallium-68 ([68Ga]Ga-NOTA-Spermine) for the imaging of the PTS in mouse models of tumor.

RESULTS

The radiochemical yield of [68Ga]Ga-NOTA-Spermine was determined to be 64-69 %, demonstrating exceptional stability and radiochemical purity (>98 %). Cellular uptake experiments revealed that A549 cells exhibited peak uptake of [68Ga]Ga-NOTA-Spermine at 90 min (15.4 % ± 0.68 %). Biodistribution analysis demonstrated significant accumulation of [68Ga]Ga-NOTA-Spermine in kidneys and liver, while exhibiting low uptake levels in muscle, brain, and bones. Furthermore, Micro-PET/CT scans conducted on A549 tumor-bearing mouse models indicated substantial uptake of [68Ga]Ga-NOTA-Spermine, with maximum tumor/muscle (T/M) ratios reaching 3.71.

CONCLUSION

These results suggest that [68Ga]Ga-NOTA-Spermine holds potential as a PET imaging agent for tumors with high levels of PTS.

Polyamine-Drug Conjugates: Do They Boost Drug Activity?

Over the past two decades, the strategy of conjugating polyamine tails with bioactive molecules such as anticancer and antimicrobial agents, as well as antioxidant and neuroprotective scaffolds, has been widely exploited to enhance their pharmacological profile. Polyamine transport is elevated in many pathological conditions, suggesting that the polyamine portion could improve cellular and subcellular uptake of the conjugate via the polyamine transporter system. In this review, we have presented a glimpse on the polyamine conjugate scenario, classified by therapeutic area, of the last decade with the aim of highlighting achievements and fostering future developments.

Strigol1/albumin/chitosan nanoparticles decrease cell viability, induce apoptosis and alter metabolomics profile in HepG2 cancer cell line

Hepatocellular carcinoma is one of the most common causes of cancer-related deaths globally. Bioavailable, effective and safe therapeutic agents are urgently needed for cancer treatment. This study evaluated the metabolomics profiling, anti-proliferative and pro-apoptotic effects of strigol/albumin/chitosan nanoparticles (S/A/CNP) on HepG2 cell line. The diameter of S/A/CNP was (5 ± 0.01) nm. The IC50 was 180.4 nM and 47.6 nM for Strigol1 and S/A/CNP, respectively, after incubation for 24 h with HepG2 cells. By increasing the concentration of S/A/CNP, there was chromatin condensation, degranulation in the cytoplasm and shrinking in cell size indicating pro-apoptotic activity. Metabolomics profiling of the exposed cells by LC/MS/MS revealed that S/A/CNP up-regulated epigenetic intermediates (spermine and spermidine) and down-regulated energy production pathway and significantly decreased glutamine (P < 0.001). These findings demonstrated that S/A/CNP has anti-proliferative, apoptotic effects and modulate energetic, and epigenetic metabolites in the hepatocellular carcinoma cell line (HepG2).

Nucleus-targeting imaging and enhanced cytotoxicity based on naphthalimide derivatives

Organelles possess critical biological effects in cellular processes. However, the relationship between organelle targeting and antitumour activity is a challenging issue. In this paper, a number of amide/acylhydrazine modified naphthalimide derivatives were designed and synthesized. Interestingly, amide modified naphthalimide derivatives NI-A-NH and NI-C-NH with (R)-piperdine and (S)-pyrrolidine functionalization exhibited enhanced cytotoxicity compared with acylhydrazine modified derivatives NI-A-2NH and NI-C-2NH. However, acylhydrazine modified derivatives NI-B-2NH and NI-D-2NH with (S)-piperdine and achiral piperdine conjugates possessed better cytotoxicity than NI-B-NH and NI-D-NH with amide modifications. Fluorescence imaging, DNA binding interactions and cell cycle analyses were further completed to clarify that the nucleus-targeting effects showed enhanced cytotoxic activity, strong DNA binding and the blocking of cells in S phase. These results provide a preliminary theoretical basis for the further design of organelle-targeting antitumour drugs.

Towards dual SPECT/optical bioimaging with a mitochondrial targeting, 99mTc(i) radiolabelled 1,8-naphthalimide conjugate

A series of six different 1,8-naphthalimide conjugated dipicolylamine ligands (L1-6) have been synthesised and characterised. The ligands possess a range of different linker units between the napthalimide fluorophore and dipcolylamine chelator which allow the overall lipophilicity to be tuned. A corresponding series of Re(i) complexes have been synthesised of the form fac-[Re(CO)3(L1-6)]BF4. The absorption and luminescence properties of the ligands and Re(i) complexes were dominated by the intramolecular charge transfer character of the substituted fluorophore (typically absorption ca. 425 nm and emission ca. 520 nm). Photophysical assessments show that some of the variants are moderately bright. Radiolabelling experiments using a water soluble ligand variant (L5) were successfully undertaken and optimised with fac-[99mTc(CO)3(H2O)3]+. Confocal fluorescence microscopy showed that fac-[Re(CO)3(L5)]+ localises in the mitochondria of MCF-7 cells. SPECT/CT imaging experiments on naïve mice showed that fac-[99mTc(CO)3(L5)]+ has a relatively high stability in vivo but did not show any cardiac uptake, demonstrating rapid clearance, predominantly via the biliary system along with a moderate amount cleared renally.

The Role of p53-Mediated Signaling in the Therapeutic Response of Colorectal Cancer to 9F, a Spermine-Modified Naphthalene Diimide Derivative

Colorectal cancer (CRC) is one of the most prevalent cancers due to its frequency and high rate of mortality. Polyamine-vectorized anticancer drugs possess multiple biological properties. Of these drugs, 9F has been shown to inhibit tumor growth and the metastasis of hepatocellular carcinoma. This current study aims to investigate the effects of 9F on CRC and determine its molecular mechanisms of action. Our findings demonstrate that 9F inhibits CRC cell growth by inducing apoptosis and cell cycle arrest, and suppresses migration, invasion and angiogenesis in vitro, resulting in the inhibition of tumor growth and metastasis in vivo. Based on RNA-seq data, further bioinformatic analyses suggest that 9F exerts its anticancer activities through p53 signaling, which is responsible for the altered expression of key regulators of the cell cycle, apoptosis, the epithelial-to-mesenchymal transition (EMT), and angiogenesis. In addition, 9F is more effective than amonafide against CRC. These results show that 9F can be considered as a potential strategy for CRC treatment.

Aminonaphthalimide hybrids of mitoxantrone and amonafide as anticancer and fluorescent cellular imaging agents

Novel water-soluble 4-aminonaphthalimides were synthesised and their cellular fluorescent imaging, cytotoxicity and ability to induced apoptosis evaluated. The lead compound 1 was designed from the cross-fertilisation of the basic hydrophilic amino pharmacophore of mitoxantrone, and an aminonaphthalimide scaffold of the drug candidate, amonafide. The compounds are also fluorescent pH probes based on photoinduced electron transfer (PET) and internal charge transfer (ICT). The compounds are sensitive to solvent polarity with large Stoke shifts (>90 nm) and provide emissive-coloured solutions (blue to yellow). Excited state pK_as of 9.0-9.3 and fluorescence quantum yields of 0.47-0.58 were determined in water. The cytotoxicity and cellular fluorescent imaging properties of the compounds were tested on human cancer cell lines K562 and MCF-7 by the MTT assay, phase contrast and fluorescence microscopy. Compounds 1 and 3 with flexible aminoalkyl chains exhibited GI₅₀ comparable to amonafide, while 2 and 4 with a rigid piperazine moiety and butyl chain are less cytotoxic. Fluorescence microscopy with 1 allowed for the visualization of the intracellular microenvironment exemplifying the potential utility of such hybrid molecules as anticancer and fluorescent cellular imaging agents.

Synthesis and in vitro antitumor activity of novel acylspermidine derivative N-(4-aminobutyl)-N-(3-aminopropyl)-8-hydroxy-dodecanamide (AAHD) against HepG2 cells

Naturally occurring polyamines like Putrescine, Spermidine, and Spermine are polycations which bind to the DNA, hence stabilizing it and promoting the essential cellular processes. Many synthetic polyamine analogues have been synthesized in the past few years, which have shown cytotoxic effects on different tumours. In the present study, we evaluated the antiproliferative effect of a novel, acylspermidine derivative, (N-(4-aminobutyl)-N-(3-aminopropyl)-8-hydroxy-dodecanamide) (AAHD) on HepG2 cells. Fluorescence staining was performed with nuclear stain (Hoechst 33342) and acridine orange/ethidium bromide double staining. Dose and the time-dependent antiproliferative effect were observed by WST-1 assays, and radical scavenging activity was measured by ROS. Morphological changes such as cell shrinkage & blebbing were analyzed by fluorescent microscopy. It was found that AAHD markedly suppressed the growth of HepG2 cells in a dose- and time-dependent manner. It was also noted that the modulation of ROS levels confirmed the radical scavenging activity. In the near future, AAHD can be a promising drug candidate in chalking out a neoplastic strategy to control the proliferation of tumour cells. This study indicated that AAHD induced anti-proliferative and pro-apoptotic activities on HCC. Since AAHD was active at micromolar concentrations without any adverse effects on the healthy cells (Fibroblasts), it is worthy of further clinical investigations.