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BackgroundBreast tumors consist of heterogeneous cellular subpopulations that differ in molecular properties and functional attributes. Cancer stem cells (CSCs) play pivotal roles in cancer therapeutic failure and metastasis. However, it remains indeterminate how CSCs determine the progression of the bulk cancer cell population.MethodsCo-culture systems in vitro and co-implantation systems in vivo were designed to characterize the interactions between breast cancer stem cells (BCSCs) and bulk cancer cells. RNA sequencing was performed to study the functional and mechanistic implications of the BCSC secretome on bulk cancer cells. A cytokine antibody array was employed to screen the differentially secreted cytokines in the BCSC secretome. Tail vein injection metastatic models and orthotopic xenograft models were applied to study the therapeutic potential of targeting IL8.ResultsWe identified that the BCSC secretome potentiated estrogen receptor (ER) activity in the bulk cancer cell population. The BCSC secretome rendered the bulk cancer cell population resistant to anti-estrogen and CDK4/6 inhibitor therapy; as well as increased the metastatic burden attributable to bulk cancer cells. Screening of the BCSC secretome identified IL8 as a pivotal factor that potentiated ERα activity, endowed tamoxifen resistance and enhanced metastatic burden by regulation of bulk cancer cell behavior. Pharmacological inhibition of IL8 increased the efficacy of fulvestrant and/or palbociclib by reversing tamoxifen resistance and abrogated metastatic burden.ConclusionTaken together, this study delineates the mechanism by which BCSCs determine the therapeutic response and metastasis of bulk cancer cells; and thereby suggests potential therapeutic strategies to ameliorate breast cancer outcomes. Video Abstract.

Cancer cells display phenotypic equilibrium between the stem-like and differentiated states during neoplastic homeostasis. The functional and mechanistic implications of this subpopulation plasticity remain largely unknown. Herein, it is demonstrated that the breast cancer stem cell (BCSC) secretome autonomously compresses the stem cell population. Co-implantation with BCSCs decreases the tumor-initiating capacity yet increases metastasis of accompanying cancer cells, wherein DKK1 is identified as a pivotal factor secreted by BCSCs for such functions. DKK1-promotes differentiation is indispensable for disseminated tumor cell metastatic outgrowth. In contrast, DKK1 inhibitors substantially relieve the metastatic burden by restraining metastatic cells in the dormant state. DKK1 increases the expression of SLC7A11 to protect metastasizing cancer cells from lipid peroxidation and ferroptosis. Combined treatment with a ferroptosis inducer and a DKK1 inhibitor exhibits synergistic effects in diminishing metastasis. Hence, this study deciphers the contribution of CSC-regulated phenotypic plasticity in metastatic colonization and provides therapeutic approaches to limit metastatic outgrowth.

Indoles and their derivatives have long been studied for their anticancer properties. Breast cancer has been treated using indole‐3‐carbinol, Indirubins, and many other naturally occurring indoles as well as their synthesized equivalents. It has been determined that the AKT pathway is a prospective target for therapeutic strategies in the treatment of breast cancer. The dysregulation of AKT pathway frequently promotes cell proliferation, survival, and resistance to apoptosis. We synthesized a novel group of bisindole clubbed pyridine and pyrimidine derivatives 5(a–l) using water as the solvent and thiamine hydrochloride as the catalyst. Compounds 5 a, 5 c, 5 d, 5 e, and 5 f are the most active against MCF‐7 cells, with an IC50 values of 2.48±0.39, 1.35±0.13, 3.36±0.53, 4.05±0.61 and 1.91±0.28 μM, respectively. Further, in silico docking of the active compound 5 c had the highest binding energy of −10.59 kcal/mol. Additionally, molecular dynanamics simulations were performed for better understanding the mode of interaction of ligand and protein. In conclusion, we have synthesized bisindoles using thiamine hydrochloride as a catalyst that target AKT pathway in breast cancer cells. [ABSTRACT FROM AUTHOR]

Breast cancer (BC) is the second leading cause of cancer‐related mortality in women, and targeting biological pathways such as the JNK pathway has proven to be a viable therapeutic target for BC therapy. Here, we synthesized piperazin‐2‐yl‐pyrimidines and evaluated them for anticancer activity against MCF‐7 cells. In addition, antioxidant, reactive oxygen species (ROS) inhibition, caspase activity, and toxicity in platelets were studied in the presence and absence of active compound IA‐6 or IA‐7. Our detailed experimental analysis found that the compound IA‐7 showed anticancer activity by either activating p‐JNK or by inducing radical species in cancer and thrombosis model. Evident to in vitro analysis, the structure based molecular interaction studies of binding of IA‐7 to JNK3S exhibited a significant binding energy of −7.56 kcal/mol which was found to be a better binder when compared to previously reported JNK inducer (PC‐12). Overall, we herein report the analytically pure IA‐7 as lead structure that could be used as a template to develop target based anticancer agents where JNK modulation is predominant. [ABSTRACT FROM AUTHOR]

Breast cancer (BC) is the second-largest cause of cancer-related deaths among women worldwide. The development of BC is a complex and multi-step process involving multiple cell types, creating a real challenge for the development of potential therapeutics against it. Several researchers have demonstrated that JNK family members have been associated with BC regulation and progression. In general, JNK is phosphorylated and activated by a number of upstream kinases, and phospho-JNK regulates a variety of cellular functions by phosphorylating c-Jun and other downstream targets. Thus, JNK has become a vital target for the development of potential therapeutics for BC treatment. In past years, electrosynthesis has emerged as a fascinating area superior to traditional chemical processes, as the evolved electrochemical technologies function at higher reaction rates for the synthesis of desired compounds. In this study, we have synthesized a series of triazole compounds using both conventional and electrochemical methods for targeting JNK in human BC cells. All the synthesized molecules were preliminarily evaluated for a cytotoxicity study against MCF-7 cells and the compound 1-(3,4-dichlorophenyl)-4-(((4-isopropyl-5-(4-methoxybenzyl)-4H-1,2,4-triazol-3-yl)thio)methyl)-1H-1,2,3-triazole (5b) is the most potent candidate among the series based on its lower inhibition concentration (IC50) of 4.78 μM. Further studies were performed to evaluate the anticancer potential of novel 5b in human BC cells and the results showed that 5b significantly inhibited colony formation, migration and induced apoptosis by increasing the expression of pro-apoptotic protein BAX, and inhibiting the anti-apoptotic protein BCL2. Furthermore, the novel 5b also induced the phosphorylation of JNK in BC cells in a dose-dependent manner. Additionally, an in silico docking study revealed that compound 5b has a strong binding affinity (−8.88 kcal mol−1) towards JNK3S. In conclusion, the novel synthesized compound 5b triggers apoptosis and JNK phosphorylation in BC cells, and may provide a new and potent therapeutic strategy against BC. [ABSTRACT FROM AUTHOR]

It is now apparent that growth hormone (GH), an anterior pituitary hormone predominantly regulating postnatal somatic growth and metabolism, is also expressed in extrapituitary tissues. An extrapituitary synthetic site of GH that has garnered interest is the de novo or enhanced expression of GH in carcinoma or other cancers. In a number of cancers, including carcinoma of the mammary gland, endometrium, liver, prostate, and colon, the expression of GH is independently associated with more advanced clinicopathologic parameters of the cancer. In some of these cancers, tumor human growth hormone (hGH) expression portends worse survival outcomes for patients. Functionally, tumor-derived hGH exerts both autocrine and paracrine functions on carcinoma cells and cancer-associated stroma. Expression of autocrine/paracrine hGH in cancer drives tumor growth, angiogenesis, metastasis, and resistance to therapy by promotion of cancer cell proliferation, survival, epithelial-to-mesenchymal transition, motility, invasion, cancer stem cell-like behavior, and metastasis. Autocrine/paracrine hGH activates oncogenic signaling pathways and specific transcriptome signatures and enhances the expression of an oncogenic secretome to promote these functions. Hence, extrapituitary expression of GH in cancer promotes cancer progression independent of endocrine hGH, and may be considered as a validated target in oncology. [ABSTRACT FROM AUTHOR]