Design, synthesis, and evaluation of indeno[2,1-c]pyrazolones for use as inhibitors against hypoxia-inducible factor (HIF)-1 transcriptional activity

Synthesis, in silico modelling, and in vitro biological evaluation of substituted pyrazole derivatives as potential anti-skin cancer, anti-tyrosinase, and antioxidant agents

Twenty-five azole compounds (P1-P25) were synthesised using regioselective base-metal catalysed and microwave-assisted approaches, fully characterised by high-resolution mass spectrometry (HRMS), nuclear magnetic resonance (NMR), and infrared spectra (IR) analyses, and evaluated for anticancer, anti-tyrosinase, and anti-oxidant activities in silico and in vitro. P25 exhibited potent anticancer activity against cells of four skin cancer (SC) lines, with selectivity for melanoma (A375, SK-Mel-28) or non-melanoma (A431, SCC-12) SC cells over non-cancerous HaCaT-keratinocytes. Clonogenic, scratch-wound, and immunoblotting assay data were consistent with anti-proliferative results, expression profiling therewith implicating intrinsic and extrinsic apoptosis activation. In a mushroom tyrosinase inhibition assay, P14 was most potent among the compounds (half-maximal inhibitory concentration where 50% of cells are dead, IC50 15.9 μM), with activity greater than arbutin and kojic acid. Also, P6 exhibited noteworthy free radical-scavenging activity. Furthermore, in silico docking and absorption, distribution, metabolism, excretion, and toxicity (ADMET) simulations predicted prominent-phenotypic actives to engage diverse cancer/hyperpigmentation-related targets with relatively high affinities. Altogether, promising early-stage hits were identified - some with multiple activities - warranting further hit-to-lead optimisation chemistry with further biological evaluations, towards identifying new skin-cancer and skin-pigmentation renormalising agents.

Expression and Clinical Significance of HIF-1α in Follicular Fluid and Granulosa Cells in Infertile PCOS Patients

The present study aimed to determine the clinical predictive significance of HIF-1α in follicular development and assisted reproductive technology (ART). We collected follicular fluid (FF) and granulosa cells (GCs) from PCOS (polycystic ovary syndrome) patients (experimental group) and other patients who were infertile due to tubal factors or male factors (control group) with IVF/ICSI-ET. The localization and expression of HIF-1α in GCs were determined by immunofluorescence staining. HIF-1α protein and mRNA expression were detected by enzyme-linked immunosorbent assay and quantitative real-time PCR, respectively. To clarify the regulation of HIF-1α by TGF-β1, we added the HIF-1α-specific blocker YC-1 to GCs. The serum AMH, LH, LH/FSH, testosterone, BMI and the number of oocytes retrieved in the PCOS group were significantly higher, while the cleavage rate was significantly lower, than those in the control group. HIF-1α protein was expressed in the cytoplasm of GCs. The expression of HIF-1α protein in the FF of the PCOS group was significantly lower than that in the control group. However, the expression of HIF-1α protein in GCs between the two groups was not significantly different. HIF-1α protein was highly expressed in large FF (follicular diameter ≥ 14 mm). Compared with the control group, the expression of HIF-1α mRNA in GCs of the PCOS group was significantly lower. The results showed a significant positive correlation between HIF-1α and TGF-β1 expression. We found that both HIF-1α and TGF-β1 were involved in the development of PCOS follicular development. The mutual regulation of HIF-1α and TGF-β1 may be one of the important mechanisms of the occurrence and development of PCOS.

Advances in antitumor research of HIF-1α inhibitor YC-1 and its derivatives

Generally, hypoxia-inducible factor-1α (HIF-1α) is highly expressed in solid tumors, it plays a key role in the occurrence and development of tumors, hindering cancer treatment in various ways. The antitumor activity and pharmacological mechanism of YC-1 [3-(5'-hydroxymethyl-2'-furyl)-1‑benzyl indazole], an HIF-1α inhibitor, and the design and synthesis of its derivatives have attracted tremendous attention in the field of antitumor research. YC-1 is a potential drug candidate and a lead compound for tumor therapy. Hence, the multifaceted mechanism of action of YC-1 and the structure activity relationship (SAR) of its derivatives are important factors to be considered for the development of HIF-1α inhibitors. Therefore, this review aimed to provide a comprehensive overview of the various antitumor mechanisms of YC-1 in antitumor research and an in-depth summary of the SAR for the development of its derivatives. A full understanding and discussion of these aspects are expected to provide potential ideas for developing novel HIF-1α inhibitors and antitumor drugs belonging to the YC-1 class. The review also highlighted the application prospects of the YC-1 class of potential antitumor candidates, and provided some unique insights about these antitumor agents.

Switchable synthesis of natural-product-like lawsones and indenopyrazoles through regioselective ring-expansion of indantrione

Lawsones and indenopyrazoles are the prevalent structural motifs and building blocks in pharmaceuticals and bioactive molecules, but their synthesis has always remained challenging as no comprehensive protocol has been outlined to date. Herein, a metal-free, ring-expansion reaction of indantrione with diazomethanes, generated in situ from the N-tosylhydrazones, has been developed for the synthesis of lawsone and indenopyrazole derivatives in acetonitrile and alcohol solvents, respectively. It provides these valuable lawsone and pyrazole skeletons in good yields and high levels of diastereoselectivity from simple and readily available starting materials. DFT calculations were used to explore the mechanism in different solutions. The synthetic application example also showed the prospects of this method for the preparation of valuable compounds.

Ruthenium-Catalyzed Divergent Acceptorless Dehydrogenative Coupling of 1,3-Diols with Arylhydrazines: Synthesis of Pyrazoles and 2-Pyrazolines

Herein, the divergent transformations of 1,3-diols with arylhydrazines via acceptorless dehydrogenative coupling reactions to selectively synthesize pyrazoles and 2-pyrazolines were reported, which were based on Ru₃(CO)₁₂/NHC-phosphine-phosphine catalytic systems. The reactions featured low catalyst loading, high selectivity, wide substrate scope, and good yields, with only water and hydrogen gas (H₂) as the byproducts.

Synthetic strategy and structure-activity relationship (SAR) studies of 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1, Lificiguat): a review

Since 1994, YC-1 (Lificiguat, 3-(5′-hydroxymethyl-2′-furyl)-1-benzylindazole) has been synthesized, and many targets for special bioactivities have been explored, such as stimulation of platelet-soluble guanylate cyclase, indirect elevation of platelet cGMP levels, and inhibition of hypoxia-inducible factor-1 (HIF-1) and NF-κB. Recently, Riociguat®, the first soluble guanylate cyclase (sGC) stimulator drug used to treat pulmonary hypertension and pulmonary arterial hypertension, was derived from the YC-1 structure. In this review, we aim to highlight the synthesis and structure–activity relationships in the development of YC-1 analogs and their possible indications.

Since 1994, YC-1 (Lificiguat) has been synthesized, and many targets for special bioactivities have been explored, such as stimulation of platelet-soluble guanylate cyclase, indirect elevation of platelet cGMP levels, and inhibition of HIF-1 and NF-κB.

Comprehensive exploration of chemical space using trisubstituted carboranes

A total of 42 trisubstituted carboranes categorised into five scaffolds were systematically designed and synthesized by exploiting the different reactivities of the twelve vertices of o-, m-, and p-carboranes to cover all directions in chemical space. Significant inhibitors of hypoxia inducible factor transcriptional activitay were mainly observed among scaffold V compounds (e.g., Vi–m, and Vo), whereas anti-rabies virus activity was observed among scaffold V (Va–h), scaffold II (IIb–g), and scaffold IV (IVb) compounds. The pharmacophore model predicted from compounds with scaffold V, which exhibited significant anti-rabies virus activity, agreed well with compounds IIb–g with scaffold II and compound IVb with scaffold IV. Normalized principal moment of inertia analysis indicated that carboranes with scaffolds I–V cover all regions in the chemical space. Furthermore, the first compounds shown to stimulate the proliferation of the rabies virus were found among scaffold V carboranes.

A facile and metal-free domino reaction of TsDAM and 2-alkenylarylaldehyde: An easy access to 8-hydroxy-2,8-dihydro indeno [2,1-c]pyrazoles

An efficient straightforward metal free domino approach was developed for the synthesis of various 8-hydroxy-2,8-dihydroindeno[2,1-c]pyrazoles via [3 + 2] cycloaddition of substituted alkenes and TsDAM (TosylDiAzoMethane). The salient features of this protocol include high efficiency, mild reaction conditions, greener solvent, metal-free reaction, scalability and broad substrate scope along with high regioselectivity and yields.

Targeting HIF-1α by newly synthesized Indolephenoxyacetamide (IPA) analogs to induce anti-angiogenesis-mediated solid tumor suppression

BACKGROUND

Hypoxic microenvironment is a common feature of solid tumors, which leads to the promotion of cancer. The transcription factor, HIF-1α, expressed under hypoxic conditions stimulates tumor angiogenesis, favoring HIF-1α as a promising anticancer agent. On the other hand, synthetic Indolephenoxyacetamide derivatives are known for their pharmacological potentiality. With this background here, we have synthesized, characterized, and validated the new IPA (8a-n) analogs for anti-tumor activity.

METHODS

The new series of IPA (8a-n) were synthesized through a multi-step reaction sequence and characterized based on the different spectroscopic analysis FT-IR, ¹H, ¹³C NMR, mass spectra, and elemental analyses. Cell-based screening of IPA (8a-n) was assessed by MTT assay. Anti-angiogenic efficacy of IPA (8k) validated through CAM, Rat corneal, tube formation and migration assay. The underlying molecular mechanism is validated through zymogram and IB studies. The in vivo anti-tumor activity was measured in the DLA solid tumor model.

RESULTS

Screening for anti-proliferative studies inferred, IPA (8k) is a lead molecule with an IC₅₀ value of _˜5 μM. Anti-angiogenic assays revealed the angiopreventive activity through inhibition of HIF-1α and modulation downstream regulatory genes, VEGF, MMPs, and P53. The results are confirmative in an in vivo solid tumor model.

CONCLUSION

The IPA (8k) is a potent anti-proliferative molecule with anti-angiogenic activity and specifically targets HIF1α, thereby modulates its downstream regulatory genes both in vitro and in vivo. The study provides scope for new target-specific drug development against HIF-1α for the treatment of solid tumors.

Novel HIF-1α inhibitor CDMP-TQZ for cancer therapy

Aim: Tumor cells adapt to hypoxic microenvironments by releasing the key transcription factor HIF-1α, which promotes angiogenesis, glycolytic phenotype, metastasis and erythropoiesis, allowing proliferation amid low oxygen levels. Therefore, therapeutic targeting of HIF-1α represents a viable strategy for cancer therapy. Methods & Results: The authors synthesized a series of novel tetrahydroquinazoline derivatives in six steps and demonstrated that their development had a unique ability to suppress HIF-1α expression through proteasomal degradation. Conclusion: Among these compounds, CDMP-TQZ (8bf) exhibited the highest antiproliferative potency in human cancer cells, in part through downregulation of HIF-1α.

Design and synthesis of 14 and 15-membered macrocyclic scaffolds exhibiting inhibitory activities of hypoxia-inducible factor 1α

Inspired by the privileged molecular skeletons of 14- and 15-membered antibiotics, we adopted a relatively unexplored synthetic approach that exploits alkaloidal macrocyclic scaffolds to generate modulators of protein-protein interactions (PPIs). As mimetics of hot-spot residues in the α-helices responsible for the transcriptional regulation, three hydrophobic sidechains were displayed on each of the four distinct macrocyclic scaffolds generating diversity of their spatial arrangements. Modular assembly of the building blocks followed by ring-closing olefin metathesis reaction and subsequent hydrogenation allowed concise and divergent synthesis of scaffolds 1-4. The 14-membered alkaloidal macrocycles 2-4 demonstrated similar inhibition of hypoxia-inducible factor (HIF)-1α transcriptional activities (IC₅₀ between 8.7 and 10 µM), and 4 demonstrated the most potent inhibition of cell proliferation in vitro (IC₅₀ = 12 µM against HTC116 colon cancer cell line). A docking model suggested that 4 could mimic the LLxxL motif in HIF-1α, in which the three sidechains are capable of matching the spatial arrangements of the protein hot-spot residues. Unlike most of the stapled peptides, the 14-membered alkaloidal scaffold has a similar size to the α-helix backbone and does not require additional atoms to induce α-helix mimetic structure. These experimental results underscore the potential of alkaloidal macrocyclic scaffolds featuring flexibly customizable skeletal, stereochemical, substitutional, and conformational properties for the development of non-peptidyl PPI modulators targeting α-helix-forming consensus sequences responsible for the transcriptional regulation.