Agent For Triple-negative Breast Cancer Research Articles

Cordycepin Enhances the Therapeutic Efficacy of Doxorubicin in Treating Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with high mortality and poor prognosis. Meanwhile, doxorubicin, a chemotherapeutic agent for triple-negative breast cancer, has poor sensitivity. The objective of this study was to examine the effect of cordycepin on doxorubicin sensitivity and efficacy in the TNBC xenograft model and explore the relevant molecular pathways. The combination of the drugs in nude mice carrying MDA-MB-231 xenografts significantly reduced the volume, size, and weight of xenografts and improved the tumor inhibition rate. The drug combination was significantly more effective than cordycepin or doxorubicin alone, reflecting the fact that cordycepin enhanced the anti-tumor effects of doxorubicin in MDA-MB-231 xenografts. At the same time, the monitoring of several biological parameters failed to detect any obvious side effects associated with this treatment. After predicting the importance of the TNF pathway in inhibiting tumor growth using network pharmacology methods, we verified the expression of TNF pathway targets via immunohistochemistry and quantitative PCR. Furthermore, a TNF-α inhibitor was able to abrogate the beneficial effects of cordycepin and doxorubicin treatment in MDA-MB-231 cells. This clearly indicates the role of TNF-α, or related molecules, in mediating the therapeutic benefits of the combined treatment in animals carrying TNBC xenografts. The observations reported here may present a new direction for the clinical treatment of TNBC.

Guanosine diphosphate-mannose suppresses homologous recombination repair and potentiates antitumor immunity in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer with poor prognosis. TNBCs with high homologous recombination deficiency (HRD) scores benefit from DNA-damaging agents, including platinum drugs and poly(ADP-ribose) polymerase (PARP) inhibitors, whereas those with low HRD scores still lack therapeutic options. Therefore, we sought to exploit metabolic alterations to induce HRD and sensitize DNA-damaging agents in TNBCs with low HRD scores. We systematically analyzed TNBC metabolomics and identified a metabolite, guanosine diphosphate (GDP)-mannose (GDP-M), that impeded homologous recombination repair (HRR). Mechanistically, the low expression of the upstream enzyme GDP-mannose-pyrophosphorylase-A (GMPPA) led to the endogenous up-regulation of GDP-M in TNBC. The accumulation of GDP-M in tumor cells further reduced the interaction between breast cancer susceptibility gene 2 (BRCA2) and ubiquitin-specific peptidase 21 (USP21), which promoted the ubiquitin-mediated degradation of BRCA2 to inhibit HRR. Therapeutically, we illustrated that the supplementation of GDP-M sensitized DNA-damaging agents to impair tumor growth in both in vitro (cancer cell line and patient-derived organoid) and in vivo (xenograft in immunodeficient mouse) models. Moreover, the combination of GDP-M with DNA-damaging agents activated STING-dependent antitumor immunity in immunocompetent syngeneic mouse models. Therefore, GDP-M supplementation combined with PARP inhibition augmented the efficacy of anti-PD-1 antibodies. Together, these findings suggest that GDP-M is a crucial HRD-related metabolite and propose a promising therapeutic strategy for TNBCs with low HRD scores using the combination of GDP-M, PARP inhibitors, and anti-PD-1 immunotherapy.

Discovery of pharmacological agents for triple-negative breast cancer (TNBC): molecular docking and molecular dynamic simulation studies on 5-lipoxygenase (5-LOX) and nuclear factor kappa B (NF-κB)

Global burden of breast cancer is expected to cross 26 million new cases by 2030. The term ‘triple negative breast cancer’ (TNBC) refers to lack of expression of hormone receptors (ER, PR and HER2). 5-Lipoxygenase (5-LOX) inhibition promotes breast cancer apoptosis, ferroptosis and inhibits metastases. Nuclear factor kappa B (NF-κB) activation induces cell survival in breast cancer through stimulation of angiogenesis. Therefore, inhibiting NF-B signalling can stop the growth of tumours. In light of these facts, an attempt is made to investigate binding characteristics of LOX inhibitors against 5-LOX (PDB-IDs 3V99 and 6N2W) and NF-κB (PDB-IDs 4KIK and 3DO7) through molecular docking, MM-GBSA calculation, molecular dynamic simulations (MDSs) and drug-likeness analysis. The eight lead molecules A169, A156, A162, A154, A102, A240, A86 and A58 were identified. The higher NF-B inhibiting potential of A169 was discovered through the sequential HTVS, SP docking and XP docking study. The hydrophobic interaction of Leu607, Phe610, Gln557 and Asn554 with 3V99 and Cys99, Glu97 and Arg20 of 4KIK is crucial for the inhibition. The LE, LLE and FQ values of A169 suggest their optimal binding with the target. This study strongly suggests the LOX and NF-κB inhibitory potential of A169, further lead optimisation and biological validation requires for the confirmations. Communicated by Ramaswamy H. Sarma

Lysosome-targeting phenalenones as efficient type I/II photosensitizers for anticancer photodynamic therapy

Development of safe and effective photosensitizers is important for enhancing the efficacy of photodynamic cancer therapy. Phenalenone is a type II photosensitizer with a high singlet oxygen quantum yield; however, its short UV absorption wavelength hinders its application in cancer imaging and in vivo photodynamic therapy. In this study, we report a new redshift phenalenone derivative, 6-amino-5-iodo-1H-phenalen-1-one (SDU Red [SR]), as a lysosome-targeting photosensitizer for triple-negative breast cancer therapy. SDU Red produced singlet oxygen (Type II reactive oxygen species [ROS]) and superoxide anion radicals (Type I ROS) upon light irradiation. It also exhibited good photostability and a remarkable phototherapeutic index (PI > 76) against triple-negative breast cancer MDA-MB-231 cancer cells. Additionally, we designed two amide derivatives, SRE-I and SRE-II, with decreased fluorescence and photosensitizing capabilities based on SDU Red as activatable photosensitizers for photodynamic cancer therapy. SRE-I and SRE-II could be further converted into the active photosensitizer SDU Red via carboxylesterase-catalyzed amide bond cleavage. Moreover, SDU Red and SRE-II induced DNA damage and cell apoptosis in the presence of light. Therefore, SRE-II can act as a promising theranostic agent for triple-negative breast cancer.

Abstract 1651: Discovery of oridonin-based proteolysis targeting chimera (PROTAC) compounds as putative protein degraders and potent anticancer agents for triple-negative breast cancer

Abstract Natural products provide a molecular starting point for the development of novel therapeutic agents including a plethora of anti-cancer drugs currently in use. Oridonin is a natural diterpene compound enriched in medicinal herb Rabdosia rubescens, and its unique anti-cancer properties have been extensively studied. However, clinical applications of oridonin are limited due to its relatively low potency. Previously, we developed a class of druglike nitrogen-enriched oridonin derivatives, including CYD0618 and others, with thiazole modifications as effective anticancer agents to inhibit breast cancer growth in vitro and in vivo. Although breast cancer screening and treatments have improved over the last half-century, aggressive subtypes like triple-negative breast cancer (TNBC) are refractory to frontline therapies, in which the STAT3 transcription factor plays a key role in developing therapeutic resistance and recurrence. Currently, there are no FDA-approved direct STAT3 inhibitors in clinical use. We reported that CYD0618 inhibits STAT3 signaling, likely through a direct interaction with STAT3. With proteolysis targeting chimera (PROTAC) technology, our team designed novel oridonin- and CYD0618-based PROTAC compounds including PW0965 and PW1087 in an attempt to achieve STAT3 binding and degradation. We determined anticancer effects of PW0965 and PW1087 on proliferation, colony formation, apoptosis and cell motility of triple-negative breast cancer (TNBC) cells MDA-MB-231 and BT549. We found that both compounds significantly inhibited the proliferation of TNBC cells. Compared with oridonin, both compounds more effectively induced apoptosis of TNBC cells. Additionally, MDA-MB-231 and BT549 cells treated with these PROTACs showed significantly reduced migration and invasion compared to control cells. PW0965 and PW1087 treatment reduced protein levels of STAT3 and its activation at Y705 residue in TNBC cells as early as 4 hours of treatment. This observed reduction in STAT3 protein on Western blot exhibited dose and time dependence. Collectively, our results demonstrate that oridonin and its analog-based PROTACs exhibit excellent potency against TNBC cells, likely through protein degradation of STAT3. The potency of PW0965 and PW1087 warrants further in vitro and in vivo investigation in cancer cells and tumor xenograft models. The molecular profiles of these PROTACs, including their interactions with STAT proteins and protein degradation, are currently under investigation. Citation Format: Ruixia Ma, Jun Li, Gabrielle R. Vontz, Pingyuan Wang, Haiying Chen, Jia Zhou, Qiang Shen. Discovery of oridonin-based proteolysis targeting chimera (PROTAC) compounds as putative protein degraders and potent anticancer agents for triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1651.

Exogenous hydrogen sulfide (H2S) exerts therapeutic potential in triple-negative breast cancer by affecting cell cycle and DNA replication pathway

Triple negative breast cancer (TNBC) is a highly aggressive subtype with a poor prognosis due to its high rates of proliferation and metastasis. Recently, hydrogen sulfide (H2S) has been recognized as a novel gasotransmitter that plays a significant role in various pathological processes, including cancer. Here, we show that exogenous H2S inhibited TNBC cancer cell proliferation, migration and invasion in vitro, and also decreased cancer malignances in the mouse model of TNBC. To investigate the underlying mechanisms of H2S's anti-cancer effects in TNBC, we performed transcriptome sequencing and bioinformatic analyses. 2121 differentially expressed genes (DEGs) were revealed, and mainly enriched in cell cycle and DNA replication pathways. Further analysis revealed changes in alternative splicing after exogenous H2S treatment. Protein-protein interaction (PPI) network analysis was performed, which identified 458 interactions among 276 DEGs enriched in cell cycle and DNA replication pathways.We identified seven hub genes (MCM3, MCM4, MCM5, MCM6, CDC6, CDC45, and GINS2) through PPI network analysis, which were up-regulated in clinical human breast cancer but down-regulated after H2S treatment. Based on the hub genes selected, we developed a model predicting that exogenous H2S mainly exerts its anti-TNBC role by delaying DNA replication. Our findings suggest that exogenous H2S has potential as a therapeutic agent in TNBC and may exert its therapeutic potential through DNA replication and the cell cycle pathway.

The synthetic molecule stauprimide impairs cell growth and migration in triple-negative breast cancer

Stauprimide, a semi-synthetic derivative of staurosporine, is known mainly for its potent differentiation-enhancing properties in embryonic stem cells. Here, we studied the effects of stauprimide in cell growth and migration of triple-negative breast cancer cells in vitro, evaluating its potential antitumoral activity in an orthotopic mouse model of breast cancer in vivo. Our results from survival curves, EdU incorporation, cell cycle analysis and annexin-V detection in MDA-MB-231 cells indicated that stauprimide inhibited cell proliferation, arresting cell cycle in G2/M without induction of apoptosis. A decrease in the migratory capability of MDA-MB-231 was also assessed in response to stauprimide. In this work we pointed to a mechanism of action of stauprimide involving the modulation of ERK1/2, Akt and p38 MAPK signalling pathways, and the downregulation of MYC in MDA-MB-231 cells. In addition, orthotopic MDA-MB-231 xenograft and 4T1 syngeneic models suggested an effect of stauprimide in vivo, increasing the necrotic core of tumors and reducing metastasis in lung and liver of mice. Together, our results point to the promising role of stauprimide as a putative therapeutic agent in triple-negative breast cancer.

Identification of necroptosis-related subtypes and prognosis model in triple negative breast cancer

BackgroundNecroptosis is considered to be a new form of programmed necrotic cell death, which is associated with metastasis, progression and prognosis of various types of tumors. However, the potential role of necroptosis-related genes (NRGs) in the triple negative breast cancer (TNBC) is unclear.MethodsWe extracted the gene expression and relevant clinicopathological data of TNBC from The Cancer Genome Atlas (TCGA) databases and the Gene Expression Omnibus (GEO) databases. We analyzed the expression, somatic mutation, and copy number variation (CNV) of 67 NRGs in TNBC, and then observed their interaction, biological functions, and prognosis value. By performing Lasso and COX regression analysis, a NRGs-related risk model for predicting overall survival (OS) was constructed and its predictive capabilities were verified. Finally, the relationship between risk_score and immune cell infiltration, tumor microenvironment (TME), immune checkpoint, and tumor mutation burden (TMB), cancer stem cell (CSC) index, and drug sensitivity were analyzed.ResultsA total 67 NRGs were identified in our analysis. A small number of genes (23.81%) detected somatic mutation, most genes appeared to have a high frequency of CNV, and there was a close interaction between them. These genes were remarkably enriched in immune-related process. A seven-gene risk_score was generated, containing TPSG1, KRT6A, GPR19, EIF4EBP1, TLE1, SLC4A7, ESPN. The low-risk group has a better OS, higher immune score, TMB and CSC index, and lower IC50 value of common therapeutic agents in TNBC. To improve clinical practicability, we added age, stage_T and stage_N to the risk_score and construct a more comprehensive nomogram for predicting OS. It was verified that nomogram had good predictive capability, the AUC values for 1-, 3-, and 5-year OS were 0.847, 0.908, and 0.942.ConclusionOur research identified the significant impact of NRGs on immunity and prognosis in TNBC. These findings were expected to provide a new strategy for personalize the treatment of TNBC and improve its clinical benefit.

Repurposing maduramicin as a novel anticancer and anti-metastasis agent for triple-negative breast cancer as enhanced by nanoemulsion

Triple-negative breast cancer (TNBC) is featured by aggression and metastasis and remains an unmet medical challenge due to high death rate. We aimed to repurpose maduramicin (MAD) as an effective drug against TNBC, and develop a nanoemulsion system to enhance anticancer efficacy of MAD. MDA-MB-231 and 4 T1 cells were used as in vitro model, and cell viability was determined by performing cell counting kit-8 and a colony-formation assay. Furthermore, MAD loaded nanoemulsion (MAD-NEs) was manufactured and characterized by a series of tests. The anticancer and anti-metastasis mechanism of MAD-NEs were assessed by performing cell cycle, apoptosis, wound-healing, transwell assay and Western blotting assays. Herein, MAD was firstly demonstrated to be an effective agent to suppress growth of TNBC cells. Subsequently, the optimized MAD-NEs were shown to have stability and high encapsulation efficiency, and could arrested cells in G0/G1 phase and induced apoptosis in TNBC cells. More importantly, MAD-NEs significantly impeded the metastasis of tumor cells, which was further demonstrated by the significant altered expression of epithelial-mesenchymal transition and extracellular matrix markers in vitro and in vivo. Moreover, compared to MAD, MAD-NEs exhibited higher efficacy in shrinking breast tumor size and repressing liver and lung metastasis in vivo, and showed excellent biocompatibility in tumor-bearing mice. The successfully prepared MAD-NEs are expected to be harnessed to suppress tumor growth, invasion and metastasis in the battle against malignant TNBC.

Halting ErbB-2 isoforms retrograde transport to the nucleus as a new theragnostic approach for triple-negative breast cancer

Triple-negative breast cancer (TNBC) is clinically defined by the absence of estrogen and progesterone receptors and the lack of membrane overexpression or gene amplification of receptor tyrosine kinase ErbB-2/HER2. Due to TNBC heterogeneity, clinical biomarkers and targeted therapies for this disease remain elusive. We demonstrated that ErbB-2 is localized in the nucleus (NErbB-2) of TNBC cells and primary tumors, from where it drives growth. We also discovered that TNBC expresses both wild-type ErbB-2 (WTErbB-2) and alternative ErbB-2 isoform c (ErbB-2c). Here, we revealed that the inhibitors of the retrograde transport Retro-2 and its cyclic derivative Retro-2.1 evict both WTErbB-2 and ErbB-2c from the nucleus of BC cells and tumors. Using BC cells from several molecular subtypes, as well as normal breast cells, we demonstrated that Retro-2 specifically blocks proliferation of BC cells expressing NErbB-2. Importantly, Retro-2 eviction of both ErbB-2 isoforms from the nucleus resulted in a striking growth abrogation in multiple TNBC preclinical models, including tumor explants and xenografts. Our mechanistic studies in TNBC cells revealed that Retro-2 induces a differential accumulation of WTErbB-2 at the early endosomes and the plasma membrane, and of ErbB-2c at the Golgi, shedding new light both on Retro-2 action on endogenous protein cargoes undergoing retrograde transport, and on the biology of ErbB-2 splicing variants. In addition, we revealed that the presence of a functional signal peptide and a nuclear export signal (NES), both located at the N-terminus of WTErbB-2, and absent in ErbB-2c, accounts for the differential subcellular distribution of ErbB-2 isoforms upon Retro-2 treatment. Our present discoveries provide evidence for the rational repurposing of Retro-2 as a novel therapeutic agent for TNBC.

JAC1 targets YY1 mediated JWA/p38 MAPK signaling to inhibit proliferation and induce apoptosis in TNBC

Triple negative breast cancer (TNBC) is a type of breast cancer with poor prognosis, and has no ideal therapeutic target and ideal medicine. Downregulation of JWA is closely related to the poor overall survival in many cancers including TNBC. In this study, we reported at the first time that JWA gene activating compound 1 (JAC1) inhibited the proliferation of TNBC in vitro and in vivo experimental models. JAC1 specifically bound to YY1 and eliminated its transcriptional inhibition of JWA gene. The rescued JWA induced G1 phase arrest and apoptosis in TNBC cells through the p38 MAPK signaling pathway. JAC1 also promoted ubiquitination and degradation of YY1. In addition, JAC1 disrupted the interaction between YY1 and HSF1, and suppressed the oncogenic role of HSF1 in TNBC through p-Akt signaling pathway. In conclusion, JAC1 suppressed the proliferation of TNBC through the JWA/P38 MAPK signaling and YY1/HSF1/p-Akt signaling. JAC1 maybe a potential therapeutic agent for TNBC.

Hexadecanoic acid-enriched extract of Halymenia durvillei induces apoptotic and autophagic death of human triple-negative breast cancer cells by upregulating ER stress

Objective: To investigate the effect of the hexane solvent fraction of Halymenia durvillei (HDHE) on triple-negative breast cancer. Methods: The phytochemical profile of HDHE was investigated by GC-MS. The cytotoxicity of HDHE against MDA-MB-231 cells was determined. The apoptotic and autophagic effects of HDHE were analyzed. The expression of molecular markers controlling apoptosis, autophagy, DNA damage, and endoplasmic reticulum (ER) stress was determined. Results: HDHE contains a mixture of fatty acids, mainly hexadecanoic acid. HDHE at a cytotoxic concentration induced apoptotic death of MDA-MB-231 cells through mitochondrial membrane dysfunction, and induction of apoptosis markers, and increased the expression of proteins related to DNA damage response. HDHE also induced the expression of LC-3, a marker of autophagic cell death at a cytotoxic concentration. Moreover, HDHE modulated the expression of ER stress genes. Conclusions: The hexadecanoic acid-enriched extract of Halymenia durvillei promotes apoptosis and autophagy of human triple-negative breast cancer cells. This extract may be further explored as an anticancer agent for triple-negative breast cancer.

Abstract ES5-2: Optimizing the management of early stage TNBC

Abstract The recent approvals of the immunotherapeutic agent pembrolizumab, the antibody-drug conjugate sacituzumab govitecan and the PARP inhibitors olaparib and talazoparib for select patients with metastatic triple negative breast cancer (TNBC) have spurred interest in evaluating these and other novel agents in patients with earlier stage disease. For the last several decades, a standard approach to treating early stage TNBC was to administer neoadjuvant chemotherapy, most often an anthracycline/taxane-based regimen. Pathologic complete response (pCR) rates generally ranged 30-40%. Trials such as CALGB 40603, GeparSixto and BrighTNess demonstrated that the addition of carboplatin to an anthracycline and taxane based chemotherapy could increase the pCR rates (53-58%). At the most recent ESMO conference, the BrighTNess investigators reported that the addition of carboplatin improved event free survival (EFS) after a median follow-up of 4.5 years. For patients not experiencing a pCR, the Create-X trial showed benefit of capecitabine in the adjuvant setting.As of August 2021, there is a new standard for treating early stage TNBC. Specifically, based on the KEYNOTE-522 trial, pembrolizumab, in combination with chemotherapy, is FDA approved for this indication. KEYNOTE-522 enrolled over 1170 stage 2-3 TNBC patients and randomized them to chemotherapy +/- pembrolizumab. The most recent report showed the trial met it’s co-primary endpoints of improved pCR (63% vs 56%) and EFS (84.5% vs 76.8%) after a median follow-up of 39 months. Importantly, the benefit was regardless of the PD-L1 status of the patient’s tumor. With the approval of pembrolizumab comes a number of questions: 1) which patients should receive this regimen which is associated with immune-related toxicities, some of which are lifelong, 2) what is the optimal chemotherapy backbone, 3) is a full year of pembrolizumab required and 4) are there other biomarkers to be explored that may predict response to therapy or the development of toxicity? Other studies either have or are evaluating other targeted agents in the preoperative setting for early stage TNBC. In a small study of 20 BRCA mutation carriers treated preoperatively with single agent talazoparib, investigators reported a pCR rate of 53%. A study looking at sacituzumab monotherapy in the preoperative setting has completed accrual and the results are awaited. These two trials begin to address the question of whether we can identify an “achilles” heel in TNBC and if so, will targeting it improve patient outcomes. Good correlative studies that provide improved understanding of the impact of these therapies on the TNBC microenvironment will help inform the next generation of trials; likely combination therapies.There is also the question of adjuvant therapy, particularly for those that do not experience a pCR with preoperative therapy. As stated above, the CREATE-X trial supports the use of capecitabine in patients with residual disease, however EA1131 demonstrated that outcomes are still poor for this population. More recently, for patients with BRCA-mutated cancers, the OlympiA trial showed benefit to a year of adjuvant olaparib. There is also growing interest in whether patients with residual disease who are at highest risk for recurrence can be identified using technologies looking for cell-free DNA to find those with minimal residual disease. Historically we’ve thought about TNBC for what it’s not – it is not ER, PR or HER2 positive. With multiple studies now showing benefit of specific agents in TNBC, the next several years will provide an opportunity to more extensively dissect triple negative tumors and their. microenvironment. This will allow us to learn what TNBC “is”, and which of likely multiple different therapeutic strategies will be best applied to which patients. Citation Format: E Mittendorf. Optimizing the management of early stage TNBC [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr ES5-2.

Evaluation of N-aryl-β-alanine derivatives as anticancer agents in triple-negative breast cancer and glioblastoma in vitro models

Synthesis of β-amino acid derivatives containing hydrazone and azole moieties is described. For this purpose, the appropriate hydrazide was treated with aromatic aldehydes, ketones and phenyl iso(thio)cyanates to obtain the desired outcome. The synthesized target compounds were evaluated for their anticancer properties. The assay displayed 3,3′-((2,6-diethylphenyl)azanediyl)bis(N′-(benzylidene)propanehydrazide) to possess the convincing anticancer effect against triple-negative breast cancer cells in vitro. To further study the anticancer properties of compounds containing a hydrazone moiety in breast cancer, series of previously and newly prepared dihydrazones were investigated. It was determined that derivatives with the bis(N′-(4-bromobenzylidene) fragment in the structure are exclusively cytotoxic to cancer cells. The most active compounds against both cell lines were those containing electron withdrawing 4-BrPh or 4-ClPh moieties, together with either chlorine, bromine or iodine groups in para position of phenyl ring. Selected two representative compounds showed migrastatic activity in MDA-MB-231 cell line, where both of them reduced the growth of breast cancer and glioblastoma cell 3D cultures and inhibited cell colony formation. 2009 Elsevier Ltd. All rights reserved.

Abstract 1454: Antitumor activity of a selective FAK/Pyk2 inhibitor, SJP1602 against TNBC as well as CRC

Abstract Focal adhesion kinase (FAK) is a cytoplasmic tyrosine kinase that serves as a key mediator in response to integrin and growth factor signaling to control multiple aspects of cellular behavior. High expression and/or aberrant activation of FAK is observed in a broad range of human cancers, contributing to malignant phenotype in cancer and development of tumor resistance. FAK, therefore, has been a prominent target in oncology and a small number of FAK inhibitors are currently in clinical development. However, selective FAK inhibitors have shown insufficient antitumor responses due to a potential compensatory role of proline-rich tyrosine kinase 2 (Pyk2), a homologue of FAK, and require dual specific FAK/Pyk2 inhibition. SJP1602 is a novel dual inhibitor of FAK and Pyk2 without multi-kinase inhibition. We have previously reported that SJP1602 is highly specific against FAK and Pyk2 and its antitumor efficacy in triple negative breast cancer (TNBC) is superior over the clinically active FAK inhibitors. In this study, we further assessed pharmacological efficacy of SJP1602 in another type of cancer, colorectal cancer (CRC). As evaluated by cell-based ELISA, SJP1602 has nanomolar potency against FAK and Pyk2 in a panel of CRC cell lines. Validation through immunoblotting analyses revealed significant reduction of FAK/Pyk2 activation by treatment of SJP1602 in CRC cell lines, consistent with previous observations in TNBC cell lines. We then investigated the inhibition efficiency of SJP1602 in three-dimensional (3D) spheroid models using the CRC cell lines. As determined by CellTiter-Glo 3D cell viability assay, SJP1602 showed the significantly lower IC50 values than other FAK inhibitors. Next, to investigate the mechanism of action (MOA) of SJP1602, we examined changes in activation of several FAK/Pyk2-mediated signaling pathways. As shown by immunoblotting analyses, SJP1602 decreased JAK2 and Akt activity and increased the expression levels of cleaved caspase 3, a critical marker of apoptosis. Further assessment of SJP1602 in vivo showed significant antitumor activities in different human CRC xenograft models containing BRAF-mutant or KRAS-mutant tumors. In addition, the specificity and MOA of SJP1602 were confirmed using xenograft tumors. In consistent with in vitro results, SJP1602 reduced JAK2 and Akt activity in tumors from mice with SJP1602 administration. Therefore, our results demonstrate that SJP1602 has the strong antitumor efficacy in vitro and in vivo via downregulation of JAK2 and PI3K/Akt signaling pathways. SJP1602 is currently undergoing preclinical toxicology studies and in vitro safety evaluation. Taken together, our data provides promising preclinical results for the further development of SJP1602 as a potent anti-cancer agent in TNBC, CRC and resistant cancer involving FAK activation. Citation Format: Kug Hwa Lee, Hyoung Min Cho, Yongbin Park, Sungpyo Hong, Soon Kil Ahn, Min-Hyo Ki. Antitumor activity of a selective FAK/Pyk2 inhibitor, SJP1602 against TNBC as well as CRC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1454.

Retraction Note to: A new synthetic derivative of cryptotanshinone KYZ3 as STAT3 inhibitor for triple-negative breast cancer therapy

Silencing STAT3 is confirmed as a promising therapeutic strategy for triple-negative breast cancer (TNBC) therapy to address the issue of its poor prognosis. In this study, the natural product cryptotanshinone was firstly remodeled and modified as a more effective STAT3 inhibitor by structure-based strategy. The synthetic derivative KYZ3 had 22–24-fold increase in antitumor activity than cryptotanshinone on two TNBC cell lines but had little effect on normal breast epithelial MCF-10A cells. Further investigation showed that KYZ3 inhibited persistent STAT3 phosphorylation. It also prevented the STAT3 protein nuclear translocation to regulate the expressions of the target oncogenes including Bax and Bcl-2. Furthermore, KYZ3 inhibited TNBC cell metastasis by decreasing the levels of MMP-9 which were directly regulated by activated STAT3. A STAT3 plasmid transfecting assay suggested that KYZ3 induced tumor cell apoptosis mainly by targeting STAT3. Finally, KYZ3 suppressed the growth of tumors resulting from subcutaneous implantation of MDA-MB-231 cells in vivo. Taken together, KYZ3 may be a promising cancer therapeutic agent for TNBC.

Exploring the Potential of Metallodrugs as Chemotherapeutics for Triple Negative Breast Cancer.

This review focuses on studies of coordination and organometallic compounds as potential chemotherapeutics against triple negative breast cancer (TNBC) which has one of the poorest prognoses and worst survival rates from all breast cancer types. At present, chemotherapy is still the standard of care for TNBC since only one type of targeted therapy has been recently developed. References for metal-based compounds studied in TNBC cell lines will be listed, and those of metal-specific reviews, but a detailed overview will also be provided on compounds studied in vivo (mostly in mice models) and those compounds for which some preliminary mechanistic data was obtained (in TNBC cell lines and tumors) and/or for which bioactive ligands have been used. The main goal of this review is to highlight the most promising metal-based compounds with potential as chemotherapeutic agents in TNBC.

Moving Towards Targeted Therapies for Triple-Negative Breast Cancer.

In this review, we discuss targets of interest in Triple-negative breast cancer (TNBC), approved targeted agents and the results of the clinical trials that led to their approval. Additionally, we review ongoing clinical trials evaluating the use of novel targeted agents in the treatment of TNBC. TNBC accounts for 15-20% of all breast cancer cases and is associated with worse clinical outcomes. Patients have a higher risk of metastatic recurrence and inferior overall survival compared to other breast cancer subtypes. Cytotoxic chemotherapy has historically been the mainstay of treatment for TNBC. In recent years, we have seen a surge in clinical trials investigating the use of targeted agents in TNBC and now have approval for targeted therapies in select patients. Inhibitors of PARP (olaparib and talazoparib), PD-L1 (atezolizumab) and an antibody drug conjugate targeting Trop-2 (sacituzumab govitecan-hziy) are now approved for the use in select groups of patients with TNBC. Various novel targeted agents as monotherapy, dual targeted combinations, and chemotherapy combinations are currently under investigation. The results are promising and may significantly improve patient outcomes in TNBC.

Discovery and optimization of withangulatin A derivatives as novel glutaminase 1 inhibitors for the treatment of triple-negative breast cancer.

To develop novel GLS1 inhibitors as effective therapeutic agents for triple-negative breast cancer (TNBC), 25 derivatives were synthesized from the natural inhibitor withangulatin A (IC50=18.2μM). Bioassay optimization identified a novel and selective GLS1 inhibitor 7 (IC50=1.08μM). In MDA-MB-231cells, 7 diminished cellular glutamate levels by blocking glutaminolysis pathway, further triggering the generation of reactive oxygen species to induce caspase-dependent apoptosis. Molecular docking indicated that 7 interacted with a new reacting site of allosteric binding pocket by forming various interactions in GLS1. The intraperitoneal administration of 7at a dose of 50mg/kg exhibited remarkable therapeutic effects and no apparent toxicity in the MDA-MB-231 xenograft model, indicating its potential as a novel GLS1 inhibitor for treatment of TNBC.

Bufalin attenuates triple-negative breast cancer cell stemness by inhibiting the expression of SOX2/OCT4.

Triple-negative breast cancer (TNBC) has the poorest prognosis among all types of breast cancer and there is yet no effective therapy. Chemotherapy is the traditional standard of care for patients with TNBC; however, treatment of TNBC with chemotherapy may lead to the enrichment of cancer stem cells (CSCs), which exhibitan enhanced capacity for self-renewal, tumor initiation and metastasis. The present study demonstrated that bufalin, a small molecular compound used in traditional Chinese medicine, exerted anticancer effects on a wide range of cancer cell lines, inhibited cell proliferation through inducing G2/M cell cycle arrest, and triggered apoptosis in the TNBC cell lines MDA-MB-231 and HCC-1937. Consistently, bufalin markedly suppressed TNBC growth in a cell line-derived xenograft model. More importantly, unlike common chemotherapeutic drugs, bufalin reduced the stemness of TNBC stem cells. A mechanistic study suggested that bufalin may suppress the proliferation of TNBC stem cells by inhibiting the expression of octamer-binding transcription factor 4 (OCT4) and sex determining region Y-box 2 (SOX2) in MDA-MB-231 and HCC-1937 cells. These results indicated that bufalin may hold promise as a therapeutic agent in TNBC, and its effects may be mediated through the SOX2/OCT4 axis.