Despite the improved ability to detect mutations in recent years, tissue specimens cannot always be procured in a clinical setting, particularly from patients with recurrence of tumors or metastasis. Therefore, the aim of this study was to investigate whether plasma is able to be used for mutation analysis instead of tissue specimens. We collected plasma from 62 patients with colorectal cancer (CRC) prior to treatment. DNA extracted from plasma and matched tumor tissues were obtained. Mutations in KRAS were amplified from the tissue specimens and sequenced by regular polymerase chain reaction (PCR) and co-amplification at lower denaturation temperature (COLD)-PCR. Plasma KRAS gene mutation on codon 12 (GGT>GAT) was detected using a nested COLD-PCR/TaqMan(®) -MGB probe. Mutations in plasma and matched tumors were compared. KRAS mutation on codon 12 (GGT>GAT) was found in 13 (21.0%) plasma specimens and 12 (19.4%) matched tumor tissues. The consistency of KRAS mutations between plasma and tumors was 75% (9/12), which indicated a high correlation between the mutations detected in plasma DNA and the mutations detected in the corresponding tumor DNA (P<0.001; correlation index, k=0.649). Notably, four (6.5%) patients with plasma DNA mutations had no detectable KRAS mutations in the corresponding primary tumors, and three (4.8%) patients with tumor DNA mutations had no detectable KRAS mutations in the corresponding plasma DNA samples. Thus, KRAS mutations in plasma DNA correlate with the mutation status in matched tumor tissues of patients with CRC. Our study provides evidence to suggest that plasma DNA may be used as a potential medium for KRAS mutation analysis in CRC using the COLD-PCR/TaqMan-MGB probe method.
Vascular smooth muscle cells (VSMCs) serve a decisive role in intimal hyperplasia, a common pathophysiological process that leads to numerous vascular disorders. The present study aimed to investigate the unknown mechanisms underlying VSMC phenotypic modulation and identified a novel microRNA (miRNA/miR)‑17‑5p/homeobox B13 (HOXB13) axis involved in the phenotypic switching, proliferation and migration of VSMCs. VSMCs were isolated from the thoracic aorta of Sprague‑Dawley rats, cell proliferation was determined by Cell Counting Kit‑8 (CCK‑8) assay, cell migration was examined by Transwell migration assay and gene expression was detected using reverse transcription‑quantitative PCR and western blot analyses. It was firstly found that incubation with platelet‑derived growth factor‑BB (PDGF‑BB) recombinant protein resulted in a significant increase in HOXB13 expression in VSMCs. Using multiple miRNA prediction tools, miR‑17‑5p was identified as a potential regulator for HOXB13, since it had a 7‑base perfect binding site and a 5‑base imperfect binding site with the 3'‑untranslated region of HOXB13 mRNA, and these sequences were highly conserved across species. The regulatory effect of miR‑17‑5p on HOXB13 was validated using luciferase reporter assays. The expression level of miR‑17‑5p was increased in VSMCs under PDGF‑BB stimulation, and was negatively correlated with HOXB13 mRNA and protein expression. Moreover, the miR‑17‑5p mimics significantly inhibited the proliferation and migration of VSMCs, while antagomiR‑17‑5p showed the opposite effects, which could be abolished by HOXB13 knockdown. The miR‑17‑5p/HOXB13 axis also regulated the expression levels of the markers of differentiated VSMCs (α‑smooth muscle actin, transgelin and smoothelin), proliferating cell nuclear antigen and cell migration proteins, including MMP‑2 and ‑9. In conclusion, the present study demonstrated that miR‑17‑5p inhibited the phenotypic modulation VSMCs stimulated by PDGF‑BB by downregulating HOXB13, indicating that these factors may be potential therapeutic targets for intimal hyperplasia.
Abstract Metastatic cancers remain clinically challenging and account for more than 90% of all cancer deaths. Drugs used to treat advanced metastatic cancers often generate drug resistance and relapse. Therefore, there is a critical need for novel therapeutic approaches for patients with advanced stage cancers that do not respond to any currently available anticancer therapies. Mebendazole and structurally related benzimidazole analogues, which are FDA approved compounds used to treat helminthic infections in the gastrointestinal track, are effective in inhibiting in vitro cancer cell proliferation. Unfortunately, their therapeutic applications in metastatic cancer are limited by their extremely low solubility and poor bioavailability. Further, the mechanism of the anticancer activities of this class of compounds is poorly defined. Here, we report the design and synthesis of water-soluble benzimidazoles as novel anticancer agents. Among them, the novel oxetanyl substituted compound, OBD9 (Methyl (5-(4-(methyl(oxetan-3-yl)amino)benzoyl)-1H-benzo[d]imidazol-2-yl)carbamate), demonstrated potent cytotoxicity towards a variety of highly aggressive cancer lines including prostate, lung, and ovarian cancers (IC50: 0.9-3.8 μM). In the NCI60 cancer cell panel screen, OBD9 broadly inhibited the proliferation of leukemia, melanoma, and breast and colon cancers. The aqueous solubility of OBD9 achieved 361 μM vs <1μM for mebendazole. In a mouse xenograft model of the highly metastatic human prostate cancer PC3MLN4, OBD9 (30 mg/kg/day, three times/week for two weeks) significantly inhibited the growth of established tumors (treatment-to-control ratio: 0.36) without noticeable toxicity. We performed broad kinase screening (KINOMEscan, DiscoverX) to explore the mechanism of action and discovered OBD9 as a potent and highly selective inhibitor of Cdc-like kinase 1 and 4 (CLK1 and 4). The Selectivity Score of OBD9 at 10 μM concentration in the 403 non-mutant kinases is 0.002; and its IC50 is 1.5 and 1.2 μM for CLK1 and CLK4, respectively. CLKs are nuclear serine/threonine (S/T) kinases that regulate gene splicing and are frequently over activated in cancers. Our results suggest that OBD9 impedes cancer growth at least in part by inhibiting CLK1/4. Citation Format: Lijun Sun, Jae Eun Cheong, Michela Zaffagni, Kun Zhou, Bruce Zetter. Discovery of novel water-soluble derivatives of mebendazole as selective CLK1/4 kinase inhibitors and their anticancer cancer activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1670.
In American men, prostate cancer is the second leading cause of cancer-related death. Dissemination of prostate cancer cells to distant organs significantly worsens patients’ prognosis, and currently there are no effective treatment options that can cure advanced-stage prostate cancer. In an effort to identify compounds selective for metastatic prostate cancer cells over benign prostate cancer cells or normal prostate epithelial cells, we applied a phenotype-based in vitro drug screening method utilizing multiple prostate cancer cell lines to test 1,120 different compounds from a commercial drug library. Top drug candidates were then examined in multiple mouse xenograft models including subcutaneous tumor growth, experimental lung metastasis, and experimental bone metastasis assays. A subset of compounds including fenbendazole, fluspirilene, clofazimine, niclosamide, and suloctidil showed preferential cytotoxicity and apoptosis towards metastatic prostate cancer cells in vitro and in vivo . The bioavailability of the most discerning agents, especially fenbendazole and albendazole, was improved by formulating as micelles or nanoparticles. The enhanced forms of fenbendazole and albendazole significantly prolonged survival in mice bearing metastases, and albendazole-treated mice displayed significantly longer median survival times than paclitaxel-treated mice. Importantly, these drugs effectively targeted taxane-resistant tumors and bone metastases – two common clinical conditions in patients with aggressive prostate cancer. In summary, we find that metastatic prostate tumor cells differ from benign prostate tumor cells in their sensitivity to certain drug classes. Taken together, our results strongly suggest that albendazole, an anthelmintic medication, may represent a potential adjuvant or neoadjuvant to standard therapy in the treatment of disseminated prostate cancer.
Abstract BRCA1 germ-line mutations are a major cause of hereditary breast cancer and BRCA1-deficient breast cancer shares many characteristics as sporadic basal-like breast cancer (BLBC). Effective therapeutic targets for BRCA1-deficient BLBC remain lacking. By utilizing a BRCA1-deficient BLBC mouse model based on intraductal injection of Krt8-Cre adenovirus to inactivate Brca1 and Trp53 in luminal mammary epithelial cells, here we report that the Wnt receptor Frizzled 7 (FZD7) serves as a biomarker and therapeutic target in the resulting mammary tumor cells and is particularly enriched in cancer stem cells / tumor-initiating cells (CSCs/TICs). Inhibiting FZD7-mediated Wnt signaling using a nontoxic FZD-binding fragment of C. difficile toxin B (TcdBFBD) attenuates growth of BRCA1-deficient tumor organoids and xenografted tumors, without damaging Wnt-sensitive tissues such as bones in vivo. Finally, FZD1/2/7-positive cells are enriched in chemotherapy-resistant cells in both BLBC and luminal breast tumors treated with cisplatin, and TcdBFBD synergizes strongly with cisplatin in inhibiting both tumor types. These findings demonstrate the therapeutic value for targeting FZD1/2/7 in treating breast cancers and establish TcdBFBD as a potential therapeutic agent targeting TICs and chemotherapy-resistant cancer cells.
Tyrosine kinase receptors mediate many critical cellular functions that contribute to tumor progression and metastasis.Recepteur d'origine nantais(RON)belongs to a subfamily of receptor tyrosine kinases(RTK)with unique expression patterns and biological activities.RON is activated by a serum-derived growth factor macrophage stimulating protein(MSP),primarily expressed in cells of epithelial origin.RON activation induced cell transformation,growth,migration and matrix invasion.We review RON molecular structure,activation,and carcinogenic mechanism related.It will contribute to cancel treatment and to discuss RON expression in the tumor.
Key words:
RON; macrophage stimulating protein; cancer; receptor tyrosine kinase
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