Therapy-induced normal tissue damage promotes breast cancer metastasis.

Disseminated tumor cells frequently exhibit a period of dormancy, rendering them chemotherapy insensitive; conversely, the systemic delivery of chemotherapies can result in normal tissue damage. Using multiple mouse and human breast cancer models, we demonstrate that prior chemotherapy administration enhances metastatic colonization and outgrowth. In vitro, chemotherapy-treated fibroblasts display a pro-tumorigenic senescence-associated secretory phenotype (SASP) and are effectively eliminated by targeting the anti-apoptotic protein BCL-xL. In vivo, chemotherapy treatment induces SASP expression in normal tissues; however, the accumulation of senescent cells is limited, and BCL-xL inhibitors are unable to reduce chemotherapy-enhanced metastasis. This likely reflects that chemotherapy-exposed stromal cells do not enter a BCL-xL-dependent phenotype or switch their dependency to other anti-apoptotic BCL-2 family members. This study highlights the role of the metastatic microenvironment in controlling outgrowth of disseminated tumor cells and the need to identify additional approaches to limit the pro-tumorigenic effects of therapy-induced normal tissue damage.

Autocrine activation of MAPK signaling mediates intrinsic tolerance to androgen deprivation in LY6D prostate cancer cells.

The emergence of castration-resistant prostate cancer remains an area of unmet clinical need. We recently identified a subpopulation of normal prostate progenitor cells, characterized by an intrinsic resistance to androgen deprivation and expression of LY6D. We here demonstrate that conditional deletion of PTEN in the murine prostate epithelium causes an expansion of transformed LY6D+ progenitor cells without impairing stem cell properties. Transcriptomic analyses of LY6D+ luminal cells identified an autocrine positive feedback loop, based on the secretion of amphiregulin (AREG)-mediated activation of mitogen-activated protein kinase (MAPK) signaling, increasing cellular fitness and organoid formation. Pharmacological interference with this pathway overcomes the castration-resistant properties of LY6D+ cells with a suppression of organoid formation and loss of LY6D+ cells in vivo. Notably, LY6D+ tumor cells are enriched in high-grade and androgen-resistant prostate cancer, providing clinical evidence for their contribution to advanced disease. Our data indicate that early interference with MAPK inhibitors can prevent progression of castration-resistant prostate cancer.

RUNX1 marks a luminal castration-resistant lineage established at the onset of prostate development.

The characterization of prostate epithelial hierarchy and lineage heterogeneity is critical to understand its regenerative properties and malignancies. Here, we report that the transcription factor RUNX1 marks a specific subpopulation of proximal luminal cells (PLCs), enriched in the periurethral region of the developing and adult mouse prostate, and distinct from the previously identified NKX3.1+ luminal castration-resistant cells. Using scRNA-seq profiling and genetic lineage tracing, we show that RUNX1+ PLCs are unaffected by androgen deprivation, and do not contribute to the regeneration of the distal luminal compartments. Furthermore, we demonstrate that a transcriptionally similar RUNX1+ population emerges at the onset of embryonic prostate specification to populate the proximal region of the ducts. Collectively, our results reveal that RUNX1+ PLCs is an intrinsic castration-resistant and self-sustained lineage that emerges early during prostate development and provide new insights into the lineage relationships of the prostate epithelium.

The prostate is part of the reproductive organs in male mammals. Many of the cells lining the inside of the prostate ­ known as 'luminal cells' ­ need hormones to survive. Certain treatments for prostate cancer, including surgical and chemical castration, lead to fewer hormones reaching the prostate, which shrinks as luminal cells die. But some of these luminal cells are able to survive the damaging effects of castration, rebuilding the prostate upon treatment with hormones, which can lead to the cancer reappearing. It is unclear which type of luminal cells survive during periods without hormones and are responsible for regenerating the prostate. RUNX1 is a protein responsible for switching genes on and off, and is usually found in blood cells, which it helps to mature and perform their roles, but has also been detected in tissues that depend on hormones. Since the luminal cells of the prostate rely on hormones, could RUNX1 also be present in these cells? To answer this question, Mével et al. used mice to determine where and when RUNX1 is found in prostate cells. Mével et al. detected high levels of RUNX1 in a patch of luminal cells at the base of the prostate. Samples of these cells were taken for further testing from developing mouse embryos, healthy adult mice and mice in which the prostate was regenerating after surgical castration. Mével et al. found that these cells were a distinct subtype of luminal cells that were able to resist the effects of castration ­ they survived without hormones. Though these cells were present during the early stages of prostate embryonic development and in healthy adult prostate tissue, they were not responsible for rebuilding the prostate after castration. Mével et al.'s results indicate that, in mice, RUNX1 may act as a marker for a subset of luminal cells that can survive after castration. Further probing the roles of these castration-resistant luminal cells in normal and cancerous prostate tissue may improve the outcome of patients with prostate cancer treated with hormone deprivation therapy.

Single-Cell Analysis Identifies LY6D as a Marker Linking Castration-Resistant Prostate Luminal Cells to Prostate Progenitors and Cancer.

The exact identity of castrate-resistant (CR) cells and their relation to CR prostate cancer (CRPC) is unresolved. We use single-cell gene profiling to analyze the molecular heterogeneity in basal and luminal compartments. Within the luminal compartment, we identify a subset of cells intrinsically resistant to castration with a bi-lineage gene expression pattern. We discover LY6D as a marker of CR prostate progenitors with multipotent differentiation and enriched organoid-forming capacity. Lineage tracing further reveals that LY6D+ CR luminal cells can produce LY6D- luminal cells. In contrast, in luminal cells lacking PTEN, LY6D+ cells predominantly give rise to LY6D+ tumor cells, contributing to high-grade PIN lesions. Gene expression analyses in patients' biopsies indicate that LY6D expression correlates with early disease progression, including progression to CRPC. Our studies thus identify a subpopulation of luminal progenitors characterized by LY6D expression and intrinsic castration resistance. LY6D may serve as a prognostic maker for advanced prostate cancer.

Discovery of 'click' 1,2,3-triazolium salts as potential anticancer drugs.

BACKGROUND: In order to increase the effectiveness of cancer treatment, new compounds with potential anticancer activities are synthesized and screened. Here we present the screening of a new class of compounds, 1-(2-picolyl)-, 4-(2-picolyl)-, 1-(2-pyridyl)-, and 4-(2-pyridyl)-3-methyl-1,2,3-triazolium salts and 'parent' 1,2,3-triazole precursors. METHODS: Cytotoxic activity of new compounds was determined by spectrophotometric MTT assay on several tumour and one normal cell line. Effect of the selected compound to bind double stranded DNA (ds DNA) was examined by testing its influence on thermal stability of calf thymus DNA while its influence on cell cycle was determined by flow cytometric analysis. Generation of reactive oxygen species (ROS) was determined by addition of specific substrate 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H2DCFDA). RESULTS: Parent triazoles were largely inactive, while some of the triazolium salts were highly cytotoxic for HeLa cells. Triazolium salts exhibited high cell-type dependent cytotoxicity against different tumour cells. Selected compound (4-(4-methoxyphenyl)-3-methyl-1-(2-picolyl)-1H-1,2,3-triazolium hexafluorophosphate(V) (2b) was significantly more cytotoxic against tumour cells than to normal cells, with very high therapeutic index 7.69 for large cell lung carcinoma H460 cells. Additionally, this compound was similarly cytotoxic against parent laryngeal carcinoma HEp-2 cells and their drug resistant 7T subline, suggesting the potential of this compound in treatment of drug resistant cancers. Compound 2b arrested cells in the G1 phase of the cell cycle. It did not bind ds DNA, but induced ROS in treated cells, which further triggered cell death. CONCLUSIONS: Our results suggest that the 'click' triazolium salts are worthy of further investigation as anti-cancer agents.

The 1,3-diaryltriazenido(p-cymene)ruthenium(II) complexes with a high in vitro anticancer activity.

1,3-Diaryltriazenes (1) were let to react with [RuCl2(p-cymene)]2 in the presence of trimethylamine to give neutral 1,3-diaryltriazenido(p-cymene)ruthenium(II) complexes, [RuCl(p-cymene)(ArNNNAr)] (2). The molecular composition of the products 2 was confirmed by NMR spectroscopy and mass spectrometry. The structures of the selected complexes were confirmed by a single crystal X-ray analysis. All triazenido-ruthenium complexes were highly cytotoxic against human cervical carcinoma HeLa cells with IC50 below 6µM, as determined by a spectrophotometric MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) method. The most active was [RuCl(p-cymene)(ArNNNAr)] (Ar=4-Cl-3-(CF3)-C6H3) (2g) with IC50 of 0.103±0.006µM. In comparison with the data for the non-coordinated triazenes 1, the triazenido-ruthenium complexes 2 exhibited up to 560-times higher activity. Three selected complexes were highly cytotoxic also against several tumor cell lines: laryngeal carcinoma HEp-2 cells and their drug-resistant HEp-2 subline (7T), colorectal carcinoma HCT-116 cells, lung adenocarcinoma H460 cells, and mammary carcinoma MDA-MB-435 cells. The compounds 2g and [RuCl(p-cymene)(ArNNNAr)] (Ar=4-I-C6H4) (2j) were similarly cytotoxic against parental and drug-resistant cells. Time and dose dependent accumulation of the cells in the S phase of the cell cycle was induced by the compound 2g, triggering apoptosis. Our preliminary results indicate triazenido-ruthenium complexes as promising anticancer drug candidates.

Synthesis and biological activity of new diazenedicarboxamides as potential anticancer agents.

To increase the effectiveness of cancer treatment, more effective anti-cancer drugs, as well as the new improved strategies of cancer treatment, are urgently needed. Our previous results have shown that various diazenes are cytotoxic to different tumor cells and can even revert the resistance to cisplatin and vincristine. We also demonstrated that unsymmetrical diazenedicarboxamides 1 and 2 exhibited promising cytotoxicity. The aim of the present study was to synthesize new diazenedicarboxamides with acceptable solubility and good cytotoxicity. Here we report the synthesis and biological evaluation of new N,N'-disubstituted diazenedicarboxamides. We found that a modification of either 1 or 2 led to the more active compounds. The most effective among them was diazenedicarboxamide 11, which can be considered as a new potential anticancer agent for the tumors of different origin, as well as for the drug resistant tumors.