Abstract Emerging evidence indicates the role of cancer stem cells (CSCs) in tumor relapse and therapeutic resistance in patients with hepatocellular carcinoma (HCC). To identify novel targets against liver CSCs, an integrative analysis of publicly available datasets involving HCC clinical and stemness-related data was employed to select genes that play crucial roles in HCC via regulation of liver CSCs. We revealed an enrichment of an interstrand cross-link repair pathway, in which ubiquitin-conjugating enzyme E2 T (UBE2T) was the most significantly upregulated. Consistently, our data showed that UBE2T was upregulated in enriched liver CSC populations. Clinically, UBE2T overexpression in HCC was further confirmed at mRNA and protein levels and was correlated with advanced tumor stage and poor patient survival. UBE2T was found to be critically involved in the regulation of liver CSCs, as evidenced by increases in self-renewal, drug resistance, tumorigenicity, and metastasis abilities. Mule, an E3 ubiquitin ligase, was identified to be the direct protein binding partner of UBE2T. Rather than the canonical role of acting as a mediator to transfer ubiquitin to E3 ligases, UBE2T is surprisingly able to physically bind and regulate the protein expression of Mule via ubiquitination. Mule was found to directly degrade β-catenin protein, and UBE2T was found to mediate liver CSC functions through direct regulation of Mule-mediated β-catenin degradation; this effect was abolished when the E2 activity of UBE2T was impaired. In conclusion, we revealed a novel UBE2T/Mule/β-catenin signaling cascade that is involved in the regulation of liver CSCs, which provides an attractive potential therapeutic target for HCC.
The size of small cell lung carcinoma (SCLC) cells has often been ambiguously defined as one and a half to four times that of a lymphocyte. The purpose of this study was to determine the ratio of nuclear diameter (ND) of SCLC cells to that of lymphocytes in the same tissue sections and to assess whether the size of SCLC cells correlates with the size of tumor specimens and crush artifact. The overall mean ND (microns +/- SD) of SCLC cells was 9.2 +/- 2.1, found in 36 oat cell carcinomas (OAT, 1,800 nuclei) and 16 intermediate cell carcinomas (INT, 800 nuclei). The mean ND of OAT and INT cells was 8.1 +/- 1.3 and 11.6 +/- 1.5, respectively. The mean ND of lymphocytes (2,600 nuclei) was 5.2 +/- 0.3. The overall mean of ND ratios (+/- SD) between SCLC cells and lymphocytes was 1.8 +/- 0.4 (median, 1.7), 1.6 +/- 0.2 for OAT and 2.2 +/- 0.3 for INT. The mean size of the 52 SCLC biopsy specimens was 0.6 +/- 0.9 cm. Of all the biopsies, 84.6% (n = 44) showed various degrees of tissue crushing. The ND of SCLC cells was associated with specimen size (P = .004) and the degree of tissue crushing (P = .001). Therefore, our findings further support the hypothesis that OAT should be considered the effect of artifact rather than a true variant of SCLC and that the ND of SCLC cells is approximately two times that of lymphocytes.
Background and Aims The survival benefit of sorafenib for patients with hepatocellular carcinoma (HCC) is unsatisfactory due to the development of adaptive resistance. Increasing evidence has demonstrated that drug resistance can be acquired by cancer cells by activating a number of signaling pathways through receptor tyrosine kinases (RTKs); nevertheless, the detailed mechanism for the activation of these alternative pathways is not fully understood. Approach and Results Given the physiological role of Src homology 2 domain–containing phosphatase 2 (SHP2) as a downstream effector of many RTKs for activation of various signaling cascades, we first found that SHP2 was markedly up‐regulated in our established sorafenib‐resistant cell lines as well as patient‐derived xenografts. Upon sorafenib treatment, adaptive resistance was acquired in HCC cells through activation of RTKs including AXL, epidermal growth factor receptor, EPH receptor A2, and insulin‐like growth factor 1 receptor, leading to RAS/mitogen‐activated protein kinase kinase (MEK)/extracellular signal–regulated kinase (ERK), and AKT reactivation. We found that the SHP2 inhibitor SHP099 abrogated sorafenib resistance in HCC cell lines and organoid culture in vitro by blocking this negative feedback mechanism. Interestingly, this sensitization effect was also mediated by induction of cellular senescence. SHP099 in combination with sorafenib was highly efficacious in the treatment of xenografts and genetically engineered models of HCC. Conclusions SHP2 blockade by SHP099 in combination with sorafenib attenuated the adaptive resistance to sorafenib by impeding RTK‐induced reactivation of the MEK/ERK and AKT signaling pathways. SHP099 in combination with sorafenib may be a safe therapeutic strategy against HCC.
Abstract Hepatocellular carcinoma (HCC) is one the most fatal cancers worldwide. Early diagnosis is crucial for curing the disease. However, patients are often diagnosis at late-stage with distant metastasis, and the prognosis of metastatic HCC is poor. Molecular pathological studies confirm that gene expression alteration plays a critical role in disease progression. Recently it has been discovered that microRNA (miRNA) can alter the gene expression at post-transcription level. This study aimed to elucidate the role of miRNA in development of metastatic HCC using an orthotopic animal model and the molecular pathway involved. Orthotopic metastasis animal model was established by implanting HCC cell lines onto the liver of the SCID mice. Tumor growth was monitored by in vivo imaging system. Primary tumor and lung metastasis were observed after 12 weeks of inoculation. Tumor were then excised and established into primary tumor cell lines (PT) and lung metastatic cell lines (LM). Functional studies comparing the PT and LM cell lines derived from HCC cell line PLC demonstrated higher cell invasion and migration ability in the metastatic cell line compared with the primary tumor cell line. In addition, the LM cell line possessed more stress fiber than the PT cell line. The PLC-derived cell lines and another metastatic HCC cell line, MHCC97H-derived cell lines were subjected to the miRNA microarray analysis. Fifteen human miRNAs were found to be differentially expressed in the LM cell lines when compared to the PT cell lines. miR-106b was one of the miRNAs which was over-expressed in LM cell lines. We further confirmed our findings in HCC clinical sample and found that miR-106b was over-expressed in HCC tumor compared with the adjacent non-tumor tissue, and its expression was significantly associated with the tumor grade (p=0.018). MicroRNA knock-down study was performed by using the miR-106b LNA knock-down probe. The miR-106b knock-down reverted the cell migration phenotype, and fluorescent staining of stress fiber formation showed that the miR-106b knock-down cells have less stress fiber formation than the parental cell lines and the scramble control. We further studied the expression of E-cadherin in PLC-PT, PLC-LM, the scramble control and the miR-106b knock-down cell lines. Our result demonstrated that miR-106b expression inversely correlated with E-cadherin level. Since decrease of E-cadherin expression is the hallmark for epithelia-mesenchymal transition (EMT), further studies will focus on the role of miR-106b in EMT of HCC cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2024.
<div>Abstract<p>A poor prognosis in head and neck squamous cell carcinoma (HNSCC) patients is commonly associated with the presence of regional metastasis. Cisplatin-based chemotherapy concurrent with radiation therapy is commonly used in the treatment of locally advanced HNSCC. However, the result is dismal due to common acquisition of chemoresistance and radioresistance. Epidemiologic studies have shown the importance of dietary substances in the prevention of HNSCC. Here, we found that lupeol, a triterpene found in fruits and vegetables, selectively induced substantial HNSCC cell death but exhibited only a minimal effect on a normal tongue fibroblast cell line <i>in vitro</i>. Down-regulation of NF-κB was identified as the major mechanism of the anticancer properties of lupeol against HNSCC. Lupeol alone was not only found to suppress tumor growth but also to impair HNSCC cell invasion by reversal of the NF-κB–dependent epithelial-to-mesenchymal transition. Lupeol exerted a synergistic effect with cisplatin, resulting in chemosensitization of HNSCC cell lines with high NF-κB activity <i>in vitro</i>. In <i>in vivo</i> studies, using an orthotopic metastatic nude mouse model of oral tongue squamous cell carcinoma, lupeol at a dose of 2 mg/animal dramatically decreased tumor volume and suppressed local metastasis, which was more effective than cisplatin alone. Lupeol exerted a significant synergistic cytotoxic effect when combined with low-dose cisplatin without side effects. Our results suggest that lupeol may be an effective agent either alone or in combination for treatment of advanced tumors. [Cancer Res 2007;67(18):8800–9]</p></div>
Supplementary Figure 2 from Lupeol Suppresses Cisplatin-Induced Nuclear Factor-κB Activation in Head and Neck Squamous Cell Carcinoma and Inhibits Local Invasion and Nodal Metastasis in an Orthotopic Nude Mouse Model
Supplementary Figure 1 from MicroRNA-616 Induces Androgen-Independent Growth of Prostate Cancer Cells by Suppressing Expression of Tissue Factor Pathway Inhibitor TFPI-2
Supplementary Methods from MicroRNA-616 Induces Androgen-Independent Growth of Prostate Cancer Cells by Suppressing Expression of Tissue Factor Pathway Inhibitor TFPI-2
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