Design, synthesis and structure-activity relationship studies of a focused library of pyrimidine moiety with anti-proliferative and anti-metastasis activities in triple negative breast cancer

Design, Synthesis, and Biochemical Evaluation of Novel MLK3 Inhibitors: A Target Hopping Example

The human kinome has tremendous medical potential. In the past decade, mixed-lineage protein kinase 3 (MLK3) has emerged as an interesting and druggable target in oncogenic signaling. The important role of MLK3 has been demonstrated in several types of cancer. In a target hopping example we started with the focal adhesion kinase (FAK) inhibitor PF-431396 (10), which shows off-target activity toward MLK3. We were able to develop highly active compounds in the single digit nanomolar range for MLK3. Furthermore, we achieved a dramatic shift in selectivity from FAK to MLK3. Here we present a new chemical class of MLK3 inhibitors, including our lead compound 37 with an outstanding IC50 value of <1 nM in a biochemical MLK3 assay while simultaneously exhibiting kinome-wide selectivity.

Developing new anticancer agents: Design, synthesis, biological evaluation and in silico study of several functionalized pyrimidine-5-carbonitriles as small molecules modulators targeting breast cancer

Committed to our growing effort addressed toward the development of potent anti-breast cancer candidates, new 4-hydrazinylpyrimidine-5-carbonitriles featuring a morpholinyl or piperidinyl moiety at the position-2 and derivatized with various functionalities at the hydrazinyl group were designed through structure optimization, and their antiproliferative potency against two human breast cancer (BC) cell lines, relative to the reference drug 5-FU, was evaluated. Compounds showing remarkable cytotoxic activity versus the hormone dependent MCF-7 cell line (IC50 = 1.62 ± 0.06 µM- 9.88 ± 0.38 µM) and the non-hormone dependent MDA-MB-231 cell line (IC50 = 3.26 ± 0.14 µM-12.93 ± 0.55 µM) were further tested by multiple assays for clarification of their potential activity. Promising derivatives revealing low damage to healthy cells were subject to enzymatic inhibitory assessment against ARO and EGFR and their activities compared to letrozole and erlotinib respectively. Compounds 3c, 6a as well as compounds 4c, 4d proved to be good inhibitors of the ARO and EGFR enzymes respectively. Active compounds were also evaluated for their underlying mode of action by further investigation for CDK, Hsp90, PI3K inhibition and compared to normal MCF-10A cells and assessed for their enhancement of the caspase 9 levels. Additionally, cell cycle analysis and apoptotic induction were performed. They demonstrated remarkable activities in the previous assays and emanated as leads as anti-breast cancer candidates. Eventually, molecular docking analysis revealed that hit compounds 3c, 4c, 4d, and 6a could bind favorably to the proposed in silico models of various protein-ligand interactions. Therefore, our promising top candidates, by demonstrating appreciable anti-breast cancer activities, present valuable prospects for optimization, potency enhancement and future application.

A comprehensive review of small molecules targeting PI3K pathway: Exploring the structural development for the treatment of breast cancer

Cancer stands as one of the deadliest diseases, ranking second in terms of its global impact. Despite the presence of numerous compelling theories concerning its origins, none have succeeded in fully elucidating the intricate nature of this ailment. Among the prevailing concerns in today's world, breast cancer proliferation remains a significant issue, particularly affecting females. The abnormal proliferation of the PI3K pathway emerges as a prominent driver of breast cancer, underscoring its role in cellular survival and proliferation. Consequently, targeting this pathway has emerged as a leading strategy in breast cancer therapeutics. Within this context, the present article explores the current landscape of anti-tumour drug development, focusing on structural activity relationships (SAR) in PI3K targeting breast cancer treatment. Notably, certain moieties like triazines, pyrimidine, quinazoline, quinoline, and pyridoxine have been explored as potential PI3K inhibitors for combating breast cancer. Various heterocyclic small molecules are undergoing clinical trials, such as Alpelisib, the first orally available FDA-approved drug targeting PI3K; others include buparlisib, pictilisib, and taselisib, which inhibit class I PI3K. These drugs are used for the treatment of breast cancer but still have various side effects with their high cost. Therefore, the primary goal of this review is to include all current advances in the development of anticancer medicines that target PI3K over-activation in the treatment of breast cancer.

Cancer targeted drug delivery using active low-density lipoprotein nanoparticles encapsulated pyrimidines heterocyclic anticancer agents as microtubule inhibitors

Recently, nanomedicine had the potential to increase the delivery of active compounds to specific cell sites. Nano-LDL particles are recognized as an excellent active nano-platform for cancer-targeted delivery. Loading of therapeutic agents into nano-LDL particles achieved by surface loading, core loading, and apolipoprotein-B100 interaction. Therefore, loading nano-LDL particles’ core with pyrimidine heterocyclic anticancer agents will increase cancer cytotoxic activity targeting tubulin protein. First, by mimicking the native LDL particle's metabolic pathway, and second the agent’s chemical functional groups like the native amino acids cytosine and thymine structures will not be recognized as a foreign entity from the cell’s immune system. Nano-LDL particles will internalize through LDL-receptors endocytosis and transport the anticancer agent into the middle of the cancer cell, reducing its side effects on other healthy cells. Generally, the data revealed that pyrimidine heterocyclic anticancer agents’ size is at the nano level. Agents’ morphological examination showed nanofibers, thin sheets, clusters, and rod-like structures. LDL particles’ size became bigger after loading with pyrimidine heterocyclic anticancer agents and ranged between 121.6 and 1045 nm. Then, particles were tested for their cytotoxicity against breast (MDA468) and prostate (DU145) cancer cell lines as surrogate models with dose-response study 10, 5, 1 µM. The IC₅₀ values of the agents against DU145 and MDA468 possessed cell growth inhibition even at the 1 µM concentration ranges of 3.88 ± 1.05 µM and 3.39 ± 0.97 µM, respectively. In sum, nano-LDL particles proved their efficiency as active drug delivery vehicles to target tubulin in cancer cells.

Targeting regulated cell death (RCD) with small-molecule compounds in triple-negative breast cancer: a revisited perspective from molecular mechanisms to targeted therapies

Triple-negative breast cancer (TNBC) is a subtype of human breast cancer with one of the worst prognoses, with no targeted therapeutic strategies currently available. Regulated cell death (RCD), also known as programmed cell death (PCD), has been widely reported to have numerous links to the progression and therapy of many types of human cancer. Of note, RCD can be divided into numerous different subroutines, including autophagy-dependent cell death, apoptosis, mitotic catastrophe, necroptosis, ferroptosis, pyroptosis and anoikis. More recently, targeting the subroutines of RCD with small-molecule compounds has been emerging as a promising therapeutic strategy, which has rapidly progressed in the treatment of TNBC. Therefore, in this review, we focus on summarizing the molecular mechanisms of the above-mentioned seven major RCD subroutines related to TNBC and the latest progress of small-molecule compounds targeting different RCD subroutines. Moreover, we further discuss the combined strategies of one drug (e.g., narciclasine) or more drugs (e.g., torin-1 combined with chloroquine) to achieve the therapeutic potential on TNBC by regulating RCD subroutines. More importantly, we demonstrate several small-molecule compounds (e.g., ONC201 and NCT03733119) by targeting the subroutines of RCD in TNBC clinical trials. Taken together, these findings will provide a clue on illuminating more actionable low-hanging-fruit druggable targets and candidate small-molecule drugs for potential RCD-related TNBC therapies.

New Insight into Triple-Negative Breast Cancer Therapy: The Potential Roles of Endoplasmic Reticulum Stress and Autophagy Mechanisms

BACKGROUND

Breast cancer is accounted as the fifth leading cause of mortality among the other cancers. Notwithstanding, Triple Negative Breast Cancer (TNBC) is responsible for 15-20% of breast cancer mortality. Despite many investigations, it remains incurable in part due to insufficient understanding of its exact mechanisms.

METHODS

A literature search was performed in PubMed, SCOPUS and Web of Science databases using the keywords autophagy, Endoplasmic Reticulum (ER) stress, apoptosis, TNBC and the combinations of these keywords.

RESULTS

It was found that autophagy plays a dual role in cancer, so that it may decrease the viability of tumor cells or act as a cytoprotective mechanism. It then appears that using compounds having modulatory effects on autophagy is of importance in terms of induction of autophagic cell death and diminishing the proliferation and metastasis of tumor cells. Also, ER stress can be modulated in order to stimulate apoptotic and autophagic cell death in tumor cells.

CONCLUSION

Perturbation in the signaling pathways related to cell survival leads to the initiation and progression of cancer. Regarding the advancement in the cancer pathology, it seems that modulation of autophagy and ER stress are promising.

Small-Molecule Drug Discovery in Triple Negative Breast Cancer: Current Situation and Future Directions

Triple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, but an effective targeted therapy has not been well-established so far. Considering the lack of effective targets, where do we go next in the current TNBC drug development? A promising intervention for TNBC might lie in de novo small-molecule drugs that precisely target different molecular characteristics of TNBC. However, an ideal single-target drug discovery still faces a huge challenge. Alternatively, other new emerging strategies, such as dual-target drug, drug repurposing, and combination strategies, may provide new insight into the improvement of TNBC therapeutics. In this review, we focus on summarizing the current situation of a series of candidate small-molecule drugs in TNBC therapy, including single-target drugs, dual-target drugs, as well as drug repurposing and combination strategies that will together shed new light on the future directions targeting TNBC vulnerabilities with small-molecule drugs for future therapeutic purposes.

Antiproliferative activity, enzymatic inhibition and apoptosis-promoting effects of benzoxazole-based hybrids on human breast cancer cells

New benzoxazole derivatives containing 1,3,4-oxadiazole, 1,2,4-triazole or triazolothiadiazine rings were synthesized and screened for their in vitro antiproliferative activities against MCF-7 and MDA-MB-231 breast cancer cell lines using MTT assay. Doxorubicin, cisplatin and 2-(4-aminophenyl)benzothiazole (CJM 126) were used as references. The most active compounds 7a, 8d, 8e and 10c were screened for their antiproliferative activities against MCF-10A normal breast cells where compounds 8e and 7a were the most selective towards MCF-7 and MDA-MB-231 cell lines, respectively compared to CJM 126. In vitro enzymatic inhibition assays of epidermal growth factor receptor (EGFR) and aromatase (ARO) enzymes were performed. Compound 7a showed inhibition of EGFR comparable to that of erlotinib while compound 8e exhibited nearly half the inhibitory activity of erlotinib towards EGFR and was more potent inhibitor of ARO than letrozole. Caspase-9 activation assay, cell cycle analysis and Annexin-V/ Propidium iodide assay performed for compounds 7a, 8d, 8e and 10c demonstrated over expression of caspase-9 protein level, pre G₁ apoptosis and high annexin V binding affinity. Therefore, these compounds are considered as potent apoptosis-promoting agents. The predicted docking studies and in silico chemo-informatic properties of compounds 7a and 8e were appropriate. Compounds 7a and 8e are promising anti-breast cancer agents exhibiting potent apoptosis-promoting properties.

Design, synthesis and anticancer activity of naphthoquinone derivatives

Basis on molecular docking and pharmacophore analysis of naphthoquinone moiety, a total of 23 compounds were designed and synthesised. With the help of reverse targets searching, anti-cancer activity was preliminarily evaluated, most of them are effective against some tumour cells, especially compound 12: 1-(5,8-dihydroxy-1,4-dioxo-1,4-dihydronaphthalen-2-yl)-4-methylpent-3-en-1-yl-4-oxo-4-((4-phenoxyphenyl)amino) butanoate whose IC₅₀ against SGC-7901 was 4.1 ± 2.6 μM. Meanwhile the anticancer mechanism of compound 12 had been investigated by AnnexinV/PI staining, immunofluorescence, Western blot assay and molecular docking. The results indicated that this compound might induce cell apoptosis and cell autophagy through regulating the PI3K signal pathway.

Discovery of novel akt1 inhibitor induces autophagy associated death in hepatocellular carcinoma cells

In this study, a series of thieno [2,3-d]pyrimidine derivatives were designed, synthesized and evaluated as novel AKT1 inhibitors. In vitro antitumor assay results showed that compounds 9d-g and 9i potently suppressed the enzymatic activities of AKT1 and potently inhibited the proliferation of HepG2, Hep3B, Huh-7 and SMMC-7721 cancer cell lines. Among these derivatives, the compound 9f demonstrated the best inhibitory activities on AKT1 (IC50 = 0.034 μM) and Huh-7 cell (IC50 = 0.076 μM). A panel of biological assays showed that compound 9f suppressed the cellular proliferation of Huh-7 through Akt/mTOR signaling pathway mediated autophagy mechanism. Furthermore, the antitumor capacity of 9f was validated in the subcutaneous Huh-7 xenograft models. Together, our results demonstrate that a novel small-molecule Akt1 inhibitor induces autophagy associated death in hepatocellular carcinoma, which may afford a potential drug candidate for targeted cancer therapy.

Benzoxazole derivatives as new generation of anti-breast cancer agents

New 2-substituted benzoxazole derivatives were synthesized and screened for their in vitro anti-proliferative activities against MCF-7 and MDA-MB-231 cell lines. Compounds 4b, 4d and 11c eliciting the highest activity against MCF-7 cells were further assayed for their cytotoxic activities against A431 and HCC827 cancer cells in addition to their in vitro inhibition of wild and mutated epidermal growth factor receptor (EGFR) enzymes. Compound 11c was the most active against A431 cells and it displayed a potent inhibition of EGFR^WT while compounds 4b and 4d elicited higher potencies than erlotinib against mutated EGFR^L858R. Compounds 4a, 6c and 8a showed the most potent cytotoxic activity against MDA-MB-231 cancer cells where compounds 4a and 6c were slightly less potent aromatase (ARO) inhibitors than letrozole. MCF-7 cells treated with compounds 4b, 4d, 11c and MDA-MB-231 cells treated with compounds 4a, 6c and 8a showed remarkable over-expression of caspase-9 protein level and elicited pre G1 apoptosis and cell cycle arrest at G2/M phase in addition to high annexin V binding affinity indicating significant apoptosis. Chemo-informatic and docking properties were also predicted. Docking results revealed that docked compounds displayed binding modes with EGFR and ARO enzymes comparable to that of the reference ligands. The benzoxazole derivatives 11c and 6c possessing amide and dithiocarbamate moieties respectively were found to be potent apoptosis-inducing anti-breast cancer agents with acceptable physicochemical properties. They exert their activity via inhibition of EGFR and ARO enzymes respectively.

Synthesis and biological evaluation of dehydroabietic acid-pyrimidine hybrids as antitumor agents

A series of novel dehydroabietic acid derivatives containing pyrimidine moieties were designed and synthesized. Some of them displayed more potent inhibitory activities compared with 5-FU.

Novel camphor-based pyrimidine derivatives induced cancer cell death through a ROS-mediated mitochondrial apoptosis pathway

A series of novel camphor-based pyrimidine derivatives (3a–3x) have been synthesized; their structures were determined by using conventional methods and compound 3f was further confirmed through single crystal XRD analysis. The cytotoxic activity of the target compounds against a panel of human normal (GES-1) and cancer cell lines (MDA-MB-231, RPMI-8226, A549) was evaluated by MTS assay. Here we found that compound 3f exhibited the strongest anti-tumor activity, comparable to that of etoposide, and had much lower cytotoxicity to normal GES-1 cells (IC₅₀ > 50 μM) than the reference drug (IC₅₀ = 8.89 μM). Subsequent mechanism studies in MDA-MB-231 cells revealed that compound 3f caused G0/G1 phase arrest and apoptosis in a dose dependent manner. Moreover, the loss of mitochondrial membrane potential and enhancement of cellular ROS levels were also observed upon 3f treatment, which indicated that 3f exerted cytotoxic activity by a ROS-mediated mitochondrial apoptosis pathway. This result was confirmed by a significant increase in the expression of pro-apoptotic proteins Bax, cytochrome C and caspase-3, and downregulation of anti-apoptosis protein Bcl-2. Overall, 3f can be adopted for further investigation in the development of antitumor agents based on natural products.

A series of novel camphor-based pyrimidine derivatives were synthesized and characterized. We found the compound 3f exhibited strongest anti-tumor activity via ROS-mediated mitochondrial apoptosis pathway.

Novel naphthalene-enoates: Design and anticancer activity through regulation cell autophagy

Eleven dihydroxy-2-(1-hydroxy-4-methylpent-3-enyl)naphthalene derivatives as anticancer agents through regulating cell autophagy were designed and synthesized. The anticancer activity results indicated that most compounds manifested obvious un-toxic effect on GES-1 and L-02 with IC₅₀ from 0.58 to 1.41 mM. Among them, (S,Z)-1-(5,8-dihydroxy-1,4-dioxo-1,4-dihydronaphthalen-2-yl)-4-methylpent-3-enyl 4-(3,4- dihydroisoquinolin-2(1 H)-yl)-4-oxobut-2-enoate (compound 4i) could induce cancer cells apoptosis. Further experiments showed that autophagy played an important role in the pro-apoptotic effect of this compound. Preliminary mechanism indicated that this compound could inhibit phosphoinositide 3-kinase/protein kinase B and the mammalian target of rapamycin (PI3K/AKT/mTOR) pathway by mediating apoptosis in an autophagy-dependent manner.

Isolation of intermediates in the synthesis of new 3,4-dihydro-2H-chromeno[2,3-d]pyrimidines

Reaction ofN-alkyl-2-imino-2H-chromene-3-carboxamides with dimethyl acetylenedicarboxylate (DMAD) in the presence of sodium carbonate as catalyst in refluxing ethanol gave new tricyclic products identified as methyl 3-alkyl-2-(2-methoxy-2-oxoethyl)-4-oxo-3,4-dihydro-2H-chromeno[2,3-d]pyrimidine-2-carboxylates. In the absence of sodium carbonate, dimethyl 2-((E)-3-(alkylcarbamoyl)-2H-chromen-2-ylideneamino)fumarates were isolated as intermediates. These intermediates could be successfully converted to the same new tricyclic products by heating in ethanol containing sodium carbonate. All new synthetic compounds were characterized on the basis of their FT-IR,1H and13C NMR spectra, and microanalytical data. To identify the correct stereoisomer of the intermediates, in one case a 2D nuclear Overhauser effect (2D-NOESY) spectrum together with density functional theory (DFT) calculation at the B3LYP/6-311+G(d,p) level of theory was used.

Narciclasine induces autophagy-dependent apoptosis in triple-negative breast cancer cells by regulating the AMPK-ULK1 axis

OBJECTIVES

Autophagy and apoptosis are major types of eukaryotic programmed cell death, and regulating these processes holds promise for treating cancers. In this study, we explored the regulation mechanisms of narciclasine to autophagy and apoptosis processes in triple-negative breast cancer.

MATERIALS AND METHODS

Effects of narciclasine on proliferation, apoptosis, and autophagy of HCC-1937 and MDA-MB-231 triple-negative breast cancer (TNBC) cells were assessed using transmission electronic microscopy, flow cytometry following staining with Annexin V-FITC and propidium iodide, RNA sequencing, real-time PCR, and Western blotting. The ability of narciclasine to inhibit growth of human HCC1937 TNBC xenografts in mice was assessed, and potential mechanisms of inhibition were explored using immunohistochemistry.

RESULTS

Narciclasine inhibited TNBC cell proliferation and induced autophagy-dependent apoptosis in a dose-dependent manner. These apoptotic effects could be reversed using autophagy inhibitors, including an AMPK inhibitor and ULK1 siRNA. Consistent with these in vitro results, narciclasine significantly inhibited TNBC tumour growth in mice by upregulating autophagy-dependent apoptosis.

CONCLUSIONS

Our findings suggest that narciclasine regulates the AMPK-ULK1 signalling axis to promote autophagy-dependent apoptosis, demonstrating therapeutic potential against TNBC.

Design, synthesis, and biological evaluation of polo-like kinase 1/eukaryotic elongation factor 2 kinase (PLK1/EEF2K) dual inhibitors for regulating breast cancer cells apoptosis and autophagy

Both PLK1 and EEF2K are serine⁄threonine kinases that play important roles in the proliferation and programmed cell death of various types of cancer. They are highly expressed in breast cancer tissues. Based on the multiple-complexes generated pharmacophore models of PLK1 and homology models of EEF2K, the integrated virtual screening is performed to discover novel PLK1/EEF2K dual inhibitors. The top ten hit compounds are selected and tested in vitro, and five of them display PLK1 and EEF2K inhibition in vitro. Based on the docking modes of the most potent hit compound, a series of derivatives are synthesized, characterized and biological assayed on the PLK1, EEF2K as well as breast cancer cell proliferation models. Compound 18i with satisfied inhibitory potency are shifted to molecular mechanism studies contained molecular dynamics simulations, cell cycles, apoptosis and autophagy assays. Our results suggested that these novel PLK1/EEF2K dual inhibitors can be used as lead compounds for further development breast cancer chemotherapy.