Cancer Stem Cell Surface Markers Research Articles

Cancer stemness contributes to cluster formation of colon cancer cells and high metastatic potentials.

The ability of cancer cells to form clusters is a characteristic feature in the development of metastatic tumours with drug resistance. Several studies demonstrated that clusters of circulating tumour cells (CTCs) have a greater metastatic potential to establish new tumours at secondary sites than single CTCs. However, the mechanism of cluster formation is not well understood. In this study, we investigated whether cancer stemness would contribute to cluster formation. We used a tumour sphere culture method to enrich cancer stem cells (CSCs) from colon cancer cells and found that during the second generation of sphere culture, clusters (between 3 and 5 cells) formed within the first 24hours, whereas the rest remained as single cells. The clusters were analysed for stemness and metastatic potential, including gene expressions for cancer stemness (CD133 and Lgr5), epithelial-mesenchymal transition (E-cadherin and TGF-β 1-3) and hypoxia-induced factors (HIF-1α and HIF-2α). The results showed that the clusters expressed higher levels of these genes and colon CSC surface markers (including CD24, CD44 and CD133) than the single cells. Among these markers, CD24 seemed the major contributor linking the cells into the clusters. These clusters also showed a stronger ability to both form colonies and migrate. Our data collectively suggest that colon cancer stemness contributes to cluster formation and that clustered cells exhibit a great metastatic potential. Our study thus provides a method to study the CTC clusters and derive insight into oncogenesis and metastasis.

Serial Xenotransplantation in NSG Mice Promotes a Hybrid Epithelial/Mesenchymal Gene Expression Signature and Stemness in Rhabdomyosarcoma Cells.

Serial xenotransplantation of sorted cancer cells in immunodeficient mice remains the most complex test of cancer stem cell (CSC) phenotype. However, we have demonstrated in various sarcomas that putative CSC surface markers fail to identify CSCs, thereby impeding the isolation of CSCs for subsequent analyses. Here, we utilized serial xenotransplantation of unsorted rhabdomyosarcoma cells in NOD/SCID gamma (NSG) mice as a proof-of-principle platform to investigate the molecular signature of CSCs. Indeed, serial xenotransplantation steadily enriched for rhabdomyosarcoma stem-like cells characterized by enhanced aldehyde dehydrogenase activity and increased colony and sphere formation capacity in vitro. Although the expression of core pluripotency factors (SOX2, OCT4, NANOG) and common CSC markers (CD133, ABCG2, nestin) was maintained over the passages in mice, gene expression profiling revealed gradual changes in several stemness regulators and genes linked with undifferentiated myogenic precursors, e.g., SOX4, PAX3, MIR145, and CDH15. Moreover, we identified the induction of a hybrid epithelial/mesenchymal gene expression signature that was associated with the increase in CSC number. In total, 60 genes related to epithelial or mesenchymal traits were significantly altered upon serial xenotransplantation. In silico survival analysis based on the identified potential stemness-associated genes demonstrated that serial xenotransplantation of unsorted rhabdomyosarcoma cells in NSG mice might be a useful tool for the unbiased enrichment of CSCs and the identification of novel CSC-specific targets. Using this approach, we provide evidence for a recently proposed link between the hybrid epithelial/mesenchymal phenotype and cancer stemness.

Cancer Stem Cell as Target of CAR-T Cell Therapy

Chimeric antigen receptor-T cell (CAR-T) therapy has been studied intensively these years and is considered a promising cancer treatment. So far, Food and Drug Administration has approved 2 CAR-T cell therapy for patients with refractory leukemia and the result is positive. However, CAR-T cell therapy is still facing several challenges, including antigen escape, which will diminish the efficacy of treatment and lead to relapse. This review investigates the potential of cancer stem cell (CSC), a small group of cancer cells that contribute to tumorigenesis, metastasis, therapy resistance and relapse, as the target of CAR-T cell therapy, focusing on representative CSC surface markers: CD123, CD133 and CD44. Evidence indicates that CAR-T cell therapy directed by CSC surface markers is effective and feasible. Therefore, CSC targeted CAR-T cell therapy is a prospective treatment for cancer.

Investigation of Relationship Between Hypoxic Process and Cancer Stem Cells in Meningioma.

To investigate the relationship between cancer stem cells (CD133 and CD44) and HIF1? expression in meningioma. In an immunohistochemistry experiment, three expert pathologists examined 100 meningioma slides stained for HIF1?, CD133, and CD44 antibodies. Statistical analyses were performed using the SPSS 23 Statistics packet program. P values < 0.05 were statistically significant. HIF1? staining was correlated with high grade (Grade 2) meningioma. Cytoplasmic staining was negatively correlated with meningioma grade. High grade meningioma was positive for nuclear HIF1? and showed increased cytoplasmic expression of CD44 and CD133. In accordance with previous studies, the level of hypoxia and HIF1? were correlated with meningioma grade. Furthermore, expression of HIF1? was correlated with expression of CD133 and CD44, which are cancer stem cell surface markers, as well as with meningioma grade. In light of these data, new treatment modalities related to CD44 and CD133 stem cell markers and to HIF1? may be developed.

Enrichment of cancer-initiating cells from colon cancer cells through porous polymeric membranes by a membrane filtration method.

Cancer-initiating cells (CICs) or cancer stem cells (CSCs) are primarily responsible for tumor initiation, growth, and metastasis and represent a few percent of the total tumor cell population. We designed a membrane filtration protocol to enrich CICs (CSCs) from the LoVo colon cancer cell line via nylon mesh filter membranes with 11 and 20 μm pore sizes and poly(lactide-co-glycolic acid)/silk screen (PLGA/silk screen) porous membranes (pore sizes of 20-30 μm). The colon cancer cell solution was filtered through the membranes to obtain a permeate solution. Subsequently, the cell culture medium was filtered through the membranes to collect the recovery solution where the cells attached to the membranes were rinsed off into the recovery solution. Then, the membranes were cultivated in the cultivation medium to collect the migrated cells from the membranes. The cells migrated from any membrane had higher expression of the CSC surface markers CD44 and CD133, had higher colony formation levels, and produced more carcinoembryonic antigen (CEA) than the colon cancer cells cultivated on conventional tissue culture plates (control). We established a method to enrich the CICs (CSCs) of colon cancer cells from migrated cells through porous polymeric membranes by the membrane filtration protocol developed in this study.

EXPRESSION OF CANCER STEM CELLS SURFACE MARKERS IN TONGUE SQUAMOUS CELL CARCINOMA CELL LINES

Cancer stem cells (CSCs) comprise subpopulation of tumor cells associated with cancer initiation, progression, and treatment failures found in several malignancies, including oral squamous cells carcinoma (OSCC). Currently, among the methods employed for detection and isolation of CSCs the most used is flow cytometry immunophenotyping. The expression of surface markers for CSCs in SCC-9 cells, derived from tongue OSCC, has not been described in the literature. Objective: To identify and compare the expression of cell surface markers associate to CSCs in the SCC9 ZsGreen and its metastatic derivative SCC9 ZsGreen LN1 cells. Methods: The CSC subpopulations in cultured SCC9 ZsGreen and SCC9 ZsGreen LN1 were identified by flow cytometry using the following surface markers: CD44 standard (and its isoforms, CD44 v3, and CD44 v6), CD133, CD326, CD24, and CD271. Results: SCC9 ZsGreen cells were significantly more positive for CD44, CD133, and CD271 while SCC9 ZsGreen LN1 expressed more CD326. The positivity for CD24 e CD44 v3 was also higher in SCC9 ZsGreen LN1, however, without statistical significance. Conclusions: The 2 OSCC cell lines presented distinct patterns of cancer stem cells surface markers. Further experiments will be needed to better characterize the CSCs populations present in SCC9 and SCC9 ZsGreen LN1 cell lines. (FAPESP 14/20832-3).

Dual-targeted therapeutic strategy combining CSC-DC-based vaccine and cisplatin overcomes chemo-resistance in experimental mice model.

Emerging evidence suggests that one of the main reasons of chemotherapy treatment failure is the development of multi-drug resistance (MDR) associated with cancer stem cells (CSCs). Our aim is to identify a therapeutic strategy based on MDR-reversing agents. CSC-enriched Ehrlich carcinoma (EC) cell cultures were prepared by drug-resistant selection method using different concentrations of cisplatin (CIS). Cell cultures following drug exposure were analyzed by flow cytometry for CSC surface markers CD44+/CD24-. We isolated murine bone marrow-derived dendritic cells (DCs) and then used them to prepare CSC-DC vaccine by pulsation with CSC-enriched lysate. DCs were examined by flow cytometry for phenotypic markers. Solid Ehrlich carcinoma bearing mice were injected with the CSC-DC vaccine in conjunction with repeated low doses of CIS. Tumor growth inhibition was evaluated and tumor tissues were excised and analyzed by real-time PCR to determine the relative gene expression levels of MDR and Bcl-2. Histopathological features of tumor tissues excised were examined. Co-treatment with CSC-DC and CIS resulted in a significant tumor growth inhibition. Furthermore, the greatest response of downregulation of MDR and Bcl-2 relative gene expression were achieved in the same group. In parallel, the histopathological observations demonstrated enhanced apoptosis and absence of mitotic figures in tumor tissues of the co-treatment group. Dual targeting of resistant cancer cells using CSC-DC vaccine along with cisplatin represents a promising therapeutic strategy that could suppress tumor growth, circumvent MDR, and increase the efficacy of conventional chemotherapies.

Silencing of long noncoding RNA HOXA11-AS inhibits the Wnt signaling pathway via the upregulation of HOXA11 and thereby inhibits the proliferation, invasion, and self-renewal of hepatocellular carcinoma stem cells

Hepatocellular carcinoma (HCC) is a major cause of cancer-related deaths, but its molecular mechanisms are not yet well characterized. Long noncoding RNAs (lncRNAs) play crucial roles in tumorigenesis, including that of HCC. However, the role of homeobox A11 antisense (HOXA11-AS) in determining HCC stem cell characteristics remains to be explained; hence, this study aimed to investigate the effects of HOXA11-AS on HCC stem cell characteristics. Initially, the expression patterns of HOXA11-AS and HOXA11 in HCC tissues, cells, and stem cells were determined. HCC stem cells, successfully sorted from Hep3B and Huh7 cells, were transfected with short hairpin or overexpression plasmids for HOXA11-AS or HOXA11 overexpression and depletion, with an aim to study the influences of these mediators on the self-renewal, proliferation, migration, and tumorigenicity of HCC stem cells in vivo. Additionally, the potential relationship and the regulatory mechanisms that link HOXA11-AS, HOXA11, and the Wnt signaling pathway were explored through treatment with Dickkopf-1 (a Wnt signaling pathway inhibitor). HCC stem cells showed high expression of HOXA11-AS and low expression of HOXA11. Both HOXA11-AS silencing and HOXA11 overexpression suppressed the self-renewal, proliferation, migration, and tumorigenicity of HCC stem cells in vivo, as evidenced by the decreased expression of cancer stem cell surface markers (CD133 and CD44) and stemness-related transcription factors (Nanog, Sox2, and Oct4). Moreover, silencing HOXA11-AS inactivated the Wnt signaling pathway by decreasing the methylation level of the HOXA11 promoter, thereby inhibiting HCC stem cell characteristics. Collectively, this study suggested that HOXA11-AS silencing exerts an antitumor effect, suppressing HCC development via Wnt signaling pathway inactivation by decreasing the methylation level of the HOXA11 promoter.

TNF-α/miR-155 axis induces the transformation of osteosarcoma cancer stem cells independent of TP53INP1

MicroRNA-155 (miR-155) has been identified to be overexpressed in various human cancers including osteosarcoma. However, whether the up-regulation of miR-155 is associated with osteosarcoma cancer stem cells (CSCs) is not well understood. In the present study, we showed that miR-155 induced the acquisition of stem-like features in U2OS osteosarcoma cells by increasing the expression of both CSCs surface markers (CD24, CD90, CD133) and CSC-related transcriptional factors (Nanog, SOX2, Oct4, Bim-1). Inflammatory factor TNF-α upregulated the miR-155 expression in U2OS cells and formed a feedback regulatory loop with miR-155. Furthermore, TNF-α/miR-155 axis promoted the cell proliferation, invasion and epithelial-mesenchymal transition (EMT) process in a TP53INP1 independent manner. We also revealed that TNF-α/miR-155 axis induced osteosarcoma CSCs transformation via ERK signaling pathway. These results indicate a crucial role of miR-155 in the acquisition of osteosarcoma CSC phenotype and miR-155 may serve as a potential target in future osteosarcoma therapy.

CD133: An emerging prognostic factor and therapeutic target in colorectal cancer.

Colorectal cancer (CRC) is one of the leading causes of death worldwide. Recently, the role of cancer stem cells (CSCs) has been highlighted as a crucial emerging factor in chemoresistance, cancer relapse, and metastasis. CD133 is a surface marker of CSCs and has been argued to have prognostic and therapeutic values in CRC along with its related pathways such as Wnt, Notch, and hedgehog. Several studies have successfully applied targeted therapies against CD133 in CRC models namely bispecific antibodies (BiAbs) and anti-Wnt and notch pathways agents. These studies have yielded initial promising results in this regard. However, none of the therapeutics have been used in the clinical setting and their efficacy and adverse effects profile are yet to be elucidated. This review aims to gather the old and most recent data on the prognostic and therapeutic values of CD133 and CD133-targeted therapies in CRC.

C-Myc Acts as a Competing Endogenous RNA to Sponge miR-34a, in the Upregulation of CD44, in Urothelial Carcinoma

MicroRNAs (miRNAs) have been shown to play a crucial role in the progression of human cancers, including urothelial carcinoma (UC), the sixth-most common cancer in the world. Among them, miR-34a has been implicated in the regulation of cancer stem cells (CSCs); however, its role in UC has yet to be fully elucidated. In this study, bioinformatics and experimental analysis confirmed that miR-34a targets CD44 (a CSC surface marker) and c-Myc (a well-known cell cycle regulator) in UC. We found that, surprisingly, most UC cell lines and patient samples did express miR-34a, although epigenetic silencing by promoter hypermethylation of miR-34a expression was observed only in UMUC3 cells, and a subset of patient samples. Importantly, overexpression of c-Myc, a frequently amplified oncogene in UC, was shown to upregulate CD44 expression through a competing endogenous RNA (ceRNA) mechanism, such that overexpression of the c-Myc 3′UTR upregulated CD44, and vice versa. Importantly, we observed a positive correlation between the expression of c-Myc and CD44 in clinical samples obtained from UC patients. Moreover, overexpression of a dominant-negative p53 mutant downregulated miR-34a, but upregulated c-Myc and CD44, in UC cell lines. Functionally, the ectopic expression of miR-34a was shown to significantly suppress CD44 expression, and subsequently, suppression of cell growth and invasion capability, while also reducing chemoresistance. In conclusion, it appears that aberrant promoter methylation, and c-Myc-mediated ceRNA mechanisms, may attenuate the function of miR-34a, in UC. The tumor suppressive role of miR-34a in controlling CSC phenotypes in UC deserves further investigation.

MiR-133b suppresses colorectal cancer cell stemness and chemoresistance by targeting methyltransferase DOT1L

Cancer stem cells (CSCs) are a subpopulation of chemoresistant cells that play a critical role in disease recurrence following chemotherapy. It has been reported that microRNA-133b (miR-133b) acts as a tumor suppressor in colorectal cancer (CRC). However, whether miR-133b is associated with CRC stemness and chemoresistance is not clear. In this study, we report that miR-133b is downregulated in colorectal spheroids, which are enriched with CSCs and display stem cell-like characteristics, including upreulation of CSCs surface markers and elevated chemoresistance. Additionally, miR-133b overexpression reduces CRC stemness and overrides chemoresistance to 5-Fluorouracil (5-FU) and oxaliplatin (OXP), indicating a negative role of miR-133b in regulating CRC stemness and chemoresistance. Moreover, miR-133b directly targets and suppresses the expression of disruptor of telomeric silencing 1-like (DOT1L), an exclusive H3K79 methyltransferase. Furthermore, miR-133b overexpression suppresses DOT1L-mediated H3K79me2 modification of stem cell genes, which is consistent with their downregulated transcription. More importantly, DOT1L restoration abrogates the suppressive effects of miR-133b on CRC stemness and chemoresistance, hence demonstrating that miR-133b regulates CRC stemness and chemoresistance through targeting DOT1L. Overall, these results imply that miR-133b might represent a novel therapeutic target in interfering CRC stemness and chemoresistance.

Differentially Expressed microRNAs in MIA PaCa-2 and PANC-1 Pancreas Ductal Adenocarcinoma Cell Lines are Involved in Cancer Stem Cell Regulation.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies, and thus better understanding of its molecular pathology is crucial for us to devise more effective treatment of this deadly disease. As cancer cell line remains a convenient starting point for discovery and proof-of-concept studies, here we report the miRNA expression characteristics of two cell lines, MIA PaCa-2 and PANC-1, and discovered three miRNAs (miR-7-5p, let-7d, and miR-135b-5p) that are involved in cancer stem cells (CSCs) suppression. After transfection of each miRNA’s mimic into PANC-1 cells which exhibits higher stemness feature than MIA-PaCa-2 cells, partial reduction of CSC surface markers and inhibition of tumor sphere formation were observed. These results enlighten us to consider miRNAs as potential therapeutic agents for pancreatic cancer patients via specific and effective inhibition of CSCs.

HR23A-knockdown lung cancer cells exhibit epithelial-to-mesenchymal transition and gain stemness properties through increased Twist1 stability

The epithelial-mesenchymal transition is a major cause of cancer metastasis, and deregulation of the transcription factor, Twist1, is a critical molecular event in the epithelial-mesenchymal transition. The importance of Twist1 protein turnover in this process has not yet been defined. Here, we show that HR23A directly targets the Twist1 protein without changing its gene transcription. Our experiments reveal that: HR23A interacts with Twist1, and this promotes the ubiquitin-mediated proteasomal degradation of Twist1. Depletion of HR23A enhances Twist1 protein levels, epithelial-mesenchymal transition, cancer cell migration and various cancer stemness properties, including the expression of major pluripotency factors, the capacity for tumor-sphere formation in culture and the expression of cancer stem cell surface markers. The increases of these stemness properties are reversed by ectopic expression of HR23A or further knockdown of Twist1 in HR23A-depleted cells. Thus, HR23A-knockdown cells appear to undergo epithelial-mesenchymal transition and take on certain attributes of cancer stemness. Together, our findings indicate that HR23A importantly contributes to regulating Twist1 protein stability, and suggest that altering the stability of Twist1 by modulating HR23A may be a new avenue for therapeutic intervention in cancer.

The Expression Analysis of Intestinal Cancer Stem Cell Marker Lgr5 in Colorectal Cancer Patients and the Correlation with Histopathological Markers.

Cancer stem cells (CSCs) have frequently been utilized in the cell characterization and identified responsible for tumor development, metastasis, recurrence, and chemoresistance. CSC surface markers function in cancer cell signaling and are indicated as potential biomarkers for cancer diagnosis and prognosis. As well, dysregulation of cancer-related signaling pathways could promote CSC development and progression. Our aim was to evaluate the expression of colorectal CSC markers and their correlation with cancer proliferation and angiogenesis. In this case-control study, total RNA was extracted from a total of 74 colorectal tumors and 74 adjacent normal tissue biopsies. Then, using a quantitative real-time PCR, the relative expression levels of Lgr5 and Lrig1 were measured in all malignant and healthy samples. Also, immunohistochemical (IHC) staining of tumor tissues was performed for Ki-67 (proliferation) and CD34 (angiogenesis) markers, and the immunoexpression staining scores were obtained. The diagnostic value of the genes was evaluated using receiver operating characteristic (ROC) curve. Possible correlation between CSC markers and immunohistochemical markers in CRC was analyzed by Pearson's correlation test and linear regression. The expression level of Lgr5 in tumor samples showed a significant increase compared with normal samples (p < 0.001) with a fold change of 2.54 (± 0.182). However, there was no significant difference in the relative expression of Lrig1 gene in tissue samples of healthy subjects and patients. The analysis of the ROC showed an AUC of 0.92 for Lgr5 and sensitivity 80% and specificity 96%. Further analysis revealed a significant correlation between mRNA levels of Lgr5 and immunoexpression of Ki-67 (r2 = 0.680, p < 0.001). The high expression levels of Lgr5 found in tumor tissues were correlated with histological parameters, indicating a significant role in CRC development and diagnosis.

Abstract 1163: HR23A expression modulates drug resistance through regulation of autophagy and stem cell properties in cancer cells

Abstract DNA-damaging agents are commonly used as anticancer therapeutics. Unfortunately, drug resistance arises through a combination of mechanisms, with the sensitivity of cells to apoptosis depending on the balance between apoptotic and survival signals. Our previous studies show that knockdown of HR23A, an accessory protein involved in nucleotide-excision repair (NER) at an early lesion-recognition step, induces autophagy, increases the resistance to cisplatin, oxaliplatin, 5-FU and docetaxel. However, knockdown of HR23A contributed no effect to the sensitivity of tamoxifen or irinotecan. In present study, we found that knockdown of HR23A displayed more sensitivity to the treatment of doxorubicin in A549 cell line. Knockdown of HR23A enhanced cell death via increased ER stress-mediated apoptosis but not autophagy, suggesting a different role of HR23A in response to doxorubicin. Further investigation revealed that HR23A-knockdown cells appear to undergo epithelial-mesenchymal transition and take on certain attributes of cancer stemness. Our experiments show that depletion of HR23A enhances epithelial-mesenchymal transition, EMT regulator protein levels such as Twist1, Slug and Zeb1, cancer cell migration and various cancer stemness properties, including the expression of major pluripotency factors, the capacity for tumor-sphere formation in culture and the expression of cancer stem cell surface markers. The increases of these stemness properties are reversed by ectopic expression of HR23A or further knockdown of Twist1 in HR23A-depleted cells. Furthermore, HR23A directly targets the Twist1 protein and contributes to regulating Twist1 protein stability without changing its gene transcription. Together, our data suggest that knockdown of HR23A induces autophagy, undergoes epithelial-mesenchymal transition and promotes stemness properties, thus leading to the resistance to DNA-damaging agents. Citation Format: Show-Mei Chuang, Chung-Yun Yu, Bang-Hung Liu, Sheng-Chih Lin, Shao-Yi Tang. HR23A expression modulates drug resistance through regulation of autophagy and stem cell properties in cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1163.

Distinct biological characterization of the CD44 and CD90 phenotypes of cancer stem cells in gastric cancer cell lines.

Recent study implicates that gastric cancer stem cells (CSCs) are capable of generating multiple types of cells to promote tumor growth and heterogeneity important for the development of gastric cancer. However, knowledge is limited regarding the expression and characteristics of marker-positive gastric CSCs. Therefore, gastric CSCs from a series of human gastric cancer cell lines (SNU-5, SNU-16, BGC-823, PAMC-82, MKN-45, and NCI-N87) using four putative CSC surface markers (CD44, CD90, CD133, and epithelial-cell adhesion molecule) were investigated the underlying mechanisms regulating such subpopulations. Only SNU-5 and SNU-16 exhibited independent co-expression of CD44+ and CD90+, which exhibited spheroid-colony formation in vitro and tumor formation in immunodeficient mice. Functional studies revealed that CD44+ cells were more invasive compared with CD90+ cells, whereas CD90+ cells exhibited higher levels of proliferation than CD44+ cells. Furthermore, serial xenotransplantation in mice of CD44+/CD90+ cells derived from SNU-5 and SNU-16 revealed rapid growth of CD90+ cells in subcutaneous lesions and a high metastatic capacity of CD44+ cells in the lung. Mechanistic analyses revealed that CD44+ cells underwent epithelial-to-mesenchymal transition (EMT) following acquisition of mesenchymal features, whereas CD90+ cells enhanced the activation of retinoblastoma phosphorylation at Ser780 and oncogenic cell cycle regulators. The expression of CD44 and CD90 in gastric cancer tissues was associated with distant metastasis and the differentiation state of tumors. These results demonstrated that CD44 and CD90 are specific biomarkers capable of identifying and isolating metastatic and tumorigenic CSCs through their ability to regulate EMT and the cell cycle in gastric cancer cell lines.

P21-Activated kinase 3 promotes cancer stem cell phenotypes through activating the Akt-GSK3β-β-catenin signaling pathway in pancreatic cancer cells.

Relative to several other p21-activated kinase (PAK) family members, the role of PAK3 in regulating cancer cell functions remains unclear. Our study obtained evidence that PAK3 regulates the Akt-GSK3β-β-catenin signaling by acting as Ser473-Akt kinase in several pancreatic cancer cell lines. Specifically, knockdown of PAK3 or overexpression of dominant-negative PAK3 inhibited the phosphorylation of Ser473-Akt and GSK3β, resulting in the proteasomal degradation of β-catenin. Conversely, overexpression of PAK3 led to activation of Akt signaling and increased β-catenin expression. These changes, however, were not noted with the silencing and/or overexpression of PAK1, PAK2, or PAK4, which underlies the impetus of PAK3 as a key effector in governing malignant phenotypes in these pancreatic cancer cells, including cancer stem cell (CSC) expansion. Accordingly, PAK3 depletion effectively suppresses tumorsphere formation, ALDH activity, and the expression of CSC surface markers. Moreover, we used a stable knockdown clone of AsPC-1 cells to demonstrate the in vivo efficacy of PAK3 inhibition in suppressing tumorigenesis and xenograft tumor growth. Together, these findings suggest the potential role of PAK3 as a target for pancreatic cancer therapy, which warrants further investigations.

A novel theranostic gold nanorods- and Adriamycin-loaded micelle for EpCAM targeting, laser ablation, and photoacoustic imaging of cancer stem cells in hepatocellular carcinoma.

Introduction and purposeCancer stem cells (CSCs) present a higher capacity to evade being killed by cancer agents and developing chemoresistance, thus leading to failure of conventional anticancer therapeutics. Nanomaterials specifically designed for targeting and treating not only tumor cells, but also CSCs, may encompass therapeutic and diagnostic tools, thus successfully eradicating the tumor.Materials and methodsPolymeric micelles simultaneously loaded with gold nanorods (GNRs) and Adriamycin were prepared and used as a novel therapeutic and diagnostic weapon. Epithelial cell adhesion molecule (EpCAM) is an important CSC surface marker and has been exploited in this work as an active targeting agent. Photoacoustic imaging was applied for GNR individuation and tissue recognition.ResultsThe nanosystem was demonstrated to be able to elicit effective targeting of cancer cells and cause their killing, in particular under laser ablation. Moreover, ex vivo photoacoustic imaging is able to clearly identify tumor regions thanks to GNR’s contrast.ConclusionThe nanosystem can be considered a powerful and promising theranostic weapon for hepatocellular carcinoma treatment.

Enhanced Kat3A/Catenin transcription: a common mechanism of therapeutic resistance.

Cancers are heterogeneous at the cellular level. Cancer stem cells/tumor initiating cells (CSC/TIC) both initiate tumorigenesis and are responsible for therapeutic resistance and disease relapse. Elimination of CSC/TIC should therefore be able to reverse therapy resistance. In principle, this could be accomplished by either targeting cancer stem cell surface markers or “stemness” pathways. Although the successful therapeutic elimination of “cancer stemness” is a critical goal, it is complex in that it should be achieved without depletion of or increases in somatic mutations in normal tissue stem cell populations. In this perspective, we will discuss the prospects for this goal via pharmacologically targeting differential Kat3 coactivator/Catenin usage, a fundamental transcriptional control mechanism in stem cell biology.