Development of multifunctional pyrrole-imidazole polyamides that increase hepatocyte growth factor and suppress transforming growth factor-β1

PURPOSE

The DNA recognition peptide compounds pyrrole-imidazole (PI) polyamides bind to the minor groove and can block the binding of transcription factors to target sequences. To develop more PI polyamides as potential treatments for fibrotic diseases, including chronic renal failure, we developed multifunctional PI polyamides that increase hepatocyte growth factor (HGF) and decrease transforming growth factor (TGF)-β1.

METHODS

We designed seven PI polyamides (HGF-1 to HGF-7) that bind to the chicken ovalbumin upstream promoter transcription factor-1 (COUP-TF1) binding site of the HGF promoter sequence. We selected PI polyamides that increase HGF and suppress TGF-β1 in human dermal fibroblasts (HDFs).

FINDINGS

Gel shift assays showed that HGF-2 and HGF-4 bound the appropriate dsDNAs. HGF-2 and HGF-4 significantly inhibited the TGF-β1 mRNA expression in HDFs stimulated by phorbol 12-myristate 13-acetate. HGF-2 and HGF-4 significantly inhibited the TGF-β1 protein expression in HDFs with siRNA targeting HGF, indicating that HGF-2 and HGF-4 directly inhibited the expression of TGF-β1.

CONCLUSION

The designed and synthetic HGF PI polyamides targeting the HGF promoter, which increased the expression of HGF and suppressed the expression of TGF-β, will be a potential practical medicine for fibrotic diseases, including progressive renal diseases.

Suppression of NSCLC A549 tumor growth by a mtDNA mutation-targeting pyrrole-imidazole polyamide-TPP and a senolytic drug

Certain somatic mutations in mtDNA were associated with tumor progression and frequently found in a homoplasmic state. We recently reported that pyrrole‐imidazole polyamide conjugated with the mitochondria‐delivering moiety triphenylphosphonium (PIP‐TPP) targeting an mtDNA mutation efficiently induced apoptosis in cancer cells with the mutation but not normal cells. Here, we synthesized the novel PIP‐TPP, CCC‐021‐TPP, targeting ND6 14582A > G homoplasmic missense mutation that is suggested to enhance metastasis of non‐small‐cell lung cancer A549 cells. CCC‐021‐TPP did not induce apoptosis but caused cellular senescence in the cells, accompanied by a significant induction of antiapoptotic BCL‐XL. Simultaneous treatment of A549 cells with CCC‐021‐TPP and the BCL‐XL selective inhibitor A‐1155463 resulted in apoptosis induction. Importantly, the combination induced apoptosis and suppressed tumor growth in an A549 xenografted model. These results highlight the potential of anticancer therapy with PIP‐TPPs targeting mtDNA mutations to induce cell death even in apoptosis‐resistant cancer cells when combined with senolytics.

A linear five-ring pyrrole-imidazole polyamide-triphenylphosphonium conjugate targeting a mitochondrial DNA mutation efficiently induces apoptosis of HeLa cybrid cells carrying the mutation

Somatic mutations in mitochondrial DNA may provide a new avenue for cancer therapy due to their associations to a number of cancers and a tendency of homoplasmicity. In consideration of mitochondrial features and its relatively small genome size, a nucleotide-based targeting approach is a considerably more promising option. To explore the efficacy of short linear N-methylpyrrole-N-methylimidazole polyamide (PI polyamide), we synthesized a five-ring short PI polyamide that provided sequence-specific homing for the A3243G mitochondrial mutation upon conjugation with triphenylphosphonium cation (TPP). This PI polyamide-TPP was able to induce cytotoxicity in HeLamtA3243G cybrid cells, while preserving preferential binding for oligonucleotides containing the A3243G motif from melting temperature assays. The PI polyamide-TPP also localized in the mitochondria in HeLamtA3243G cells and induced mitochondrial reactive oxygen species production, mitophagy and apoptosis in a mutation-specific fashion compared to the wild-type HeLamtHeLa cybrids; normal human dermal fibroblasts were also relatively unaffected to suggest discriminating selectivity for the mutant mitochondria, offering a novel outlook for cancer therapy via mitochondrial homing of short linear PIP-TPPs.

A novel pyrrole-imidazole polyamide targets Aurora kinase A and suppresses tumor growth in vivo

Aurora kinase A (Aurora A) plays a critical role in regulating cell mitotic progression and has been considered as a promising drug target for cancer therapy. To develop a novel molecule targeting Aurora A with high selectivity and efficacy, we designed and synthesized a pyrrole-imidazole polyamide (PIP) Hoechst conjugate, PIP-Ht, targeting to a cell-cycle regulated DNA sequence locating at the promoter of human Aurora A gene (AURKA). PIP-Ht potently suppressed AURKA promoter activities, mRNA expression and protein level, induced tumor cell cycle delay and inhibited tumor cell proliferation in vitro. Furthermore, subcutaneous injection of PIP-Ht into mice bearing human cancer xenografts induced significant tumor growth suppression and cell apoptosis. Collectively, PIP-Ht exhibits the potential as an effective therapeutic candidate for the tumor treatment.

Repression of the transcriptional activity of ERRα with sequence-specific DNA-binding polyamides

The orphan nuclear receptors estrogen-related receptors (ERRs) bind to the estrogen-related receptor response element (ERRE) to regulate transcriptional programs in cellular metabolism and cancer cell growth. In this study, we evaluated the potential for a pyrrole-imidazole polyamide to block ERRα binding to ERREs to inhibit gene expression. We demonstrated that the ERRE-targeted polyamide 1 blocked the binding of ERRα to the consensus ERRE and reduced the transcriptional activity of ERRα in cell culture. We further showed that inhibiting ERRα transcriptional activity with polyamide 1 led to reduced mitochondrial oxygen consumption, a primary biological effect regulated by ERRα. Finally, our data demonstrated that polyamide 1 is an inhibitor for cancer cell growth.

An investigation of targeted inhibition of transcription factor activity with pyrrole imidazole polyamide (PA) in chronic myeloid leukemia (CML) blast crisis cells

Tyrosine kinase inhibitor (TKI) therapy is the standard treatment for chronic phase (CP)-chronic myeloid leukemia (CML), yet patients in blast crisis (BC) phase of CML are unlikely to respond to TKI therapy. The transcription factor E2F1 is a down-stream target of the tyrosine kinase BCR-ABL1 and is up-regulated in TKI-resistant leukemia stem cells (LSC). Pyrrole imidazole polyamides (PA) are minor groove binders which can be programmed to target DNA sequences in a gene-selective manner. This manuscript describes such an approach with a PA designed to down-regulate E2F1 controlled gene expression by targeting a DNA sequence within 100 base pairs (bp) upstream of the E2F1 consensus sequence. Human BC-CML KCL22 cells were assessed after treatment with PA, TKI or their combination. Our PA inhibited BC-CML cell expansion based on cell density analysis compared to an untreated control after a 48-hour time-course of PA treatment. However, no evidence of cell cycle arrest was observed among BC-CML cells treated with PA, with respect to their no drug control counterparts. Thus, this work demonstrates that PAs are effective in inhibiting E2F1 TF activity which results in a temporal reduction in BC-CML cell number. We envisage that PAs could be used in the future to map genes under E2F1 control in CML LSCs.

Hydrophobic structure of hairpin ten-ring pyrrole-imidazole polyamides enhances tumor tissue accumulation/retention in vivo

To examine the hydrophobic structure of PI polyamides on tumor accumulation in vivo, PI polyamide-fluorescein conjugates 1-5 with the distinct number of N-methylimidazole (Im) units were synthesized. There existed an inverse relationship between the Im unit number of the compounds and their hydrophobicity. Compound 1 with one Im unit and 3 with three Im units accumulated and retained preferentially in tumor tissues compared to 5 with five Im units. These results suggest the importance of a PI polyamide's primary structure, which partly contributes to its hydrophobic property, on its accumulation and/or retention in tumor tissues in vivo.

Review of novel therapeutic medicines targeting androgen signaling in castration-resistant prostate cancer

Prostate cancer is the most common male malignant neoplasm. Androgens and the androgen receptor (AR) play a key role in the onset and progression of prostate cancer. The expression of the AR is still preserved in the majority of patients with castration-resistant prostate cancer (CRPC). CRPC is considered to be induced by the following mechanisms: (1) sustained AR activation by enhancing intracellular conversion of adrenal androgens to dehydrotestosterone via a de novo route; (2) AR hypersensitivity; (3) promiscuous activation of AR signaling; and (4) outlaw pathways. Recent advances in the treatment of CRPC include novel medicines targeting AR signaling pathways. In addition, functional molecular studies have shown that some of the AR-regulated genes and AR coregulators are prognostic markers and potential therapeutic targets for prostate cancer, particularly in the castration-resistant state. Therefore, identification of the AR signaling pathways responsible for establishment of CRPC is critical for developing new strategies for the treatment of CRPC.