Christine Earle

Stem cell marker (Nanog) and Stat-3 signaling promote MicroRNA-21 expression and chemoresistance in hyaluronan/CD44-activated head and neck squamous cell carcinoma cells.

MicroRNAs are often associated with the pathogenesis of many cancers, including head and neck squamous cell carcinoma (HNSCC). In particular, microRNA-21 (miR-21) appears to have a critical role in tumor cell survival, chemoresistance and HNSCC progression. In this study, we investigated matrix hyaluronan (HA)-induced CD44 (a primary HA receptor) interaction with the stem cell markers, Nanog and Stat-3, in HNSCC cells (HSC-3 cells). Our results indicate that HA binding to CD44 promotes Nanog–Stat-3 (also tyrosine phosphorylated Stat-3) complex formation, nuclear translocation and transcriptional activation. Further analyses reveal that miR-21 is controlled by an upstream promoter containing Stat-3 binding site(s), while chromatin immunoprecipitation assays demonstrate that stimulation of miR-21 expression by HA/CD44 signaling is Nanog/Stat-3-dependent in HNSCC cells. This process results in a decrease of a tumor suppressor protein (PDCD4), and an upregulation of i nhibitors of the apoptosis family of proteins (IAPs) as well as chemoresistance in HSC-3 cells. Treatment of HSC-3 cells with Nanog- and/or Stat-3-specific small interfering RNAs effectively blocks HA-mediated Nanog–Stat-3 signaling events, abrogates miR-21 production and increases PDCD4 expression. Subsequently, this Nanog–Stat-3 signaling inhibition causes downregulation of survival protein (IAP) expression and enhancement of chemosensitivity. To further evaluate the role of miR-21 in tumor cell-specific functions, HSC-3 cells were also transfected with a specific anti-miR-21 inhibitor in order to silence miR-21 expression and block its target functions. Our results demonstrate that anti-miR-21 inhibitor not only upregulates PDCD4 expression but also decreases IAP expression and enhances chemosensitivity in HA-treated HNSCC cells. Together, these findings indicate that the HA-induced CD44 interaction with Nanog and Stat-3 has a pivotal role in miR-21 production leading to PDCD4 reduction, IAP upregulation and chemoresistance in HNSCC cells. This novel Nanog/Stat-3 signaling pathway-specific mechanism involved in miR-21 production is significant for the formation of future intervention strategies in the treatment of HA/CD44-activated HNSCC.

Hyaluronan-CD44v3 Interaction with Oct4-Sox2-Nanog Promotes miR-302 Expression Leading to Self-renewal, Clonal Formation, and Cisplatin Resistance in Cancer Stem Cells from Head and Neck Squamous Cell Carcinoma

Background: Head and neck cancer contains cancer stem cells (CSCs) characterized by a high level of CD44 expression. Results: We discovered a new hyaluronan (HA)-CD44-mediated Oct4, Sox2, and Nanog pathway that regulates miR-302 production in CSCs. Conclusion: HA-CD44v3-activated Oct4-Sox2-Nanog signaling and miR-302 play a pivotal role in CSC functions. Significance: This information should provide new drug targets to treat head and neck cancer. Human head and neck squamous cell carcinoma (HNSCC) is a highly malignant cancer associated with major morbidity and mortality. In this study, we determined that human HNSCC-derived HSC-3 cells contain a subpopulation of cancer stem cells (CSCs) characterized by high levels of CD44v3 and aldehyde dehydrogenase-1 (ALDH1) expression. These tumor cells also express several stem cell markers (the transcription factors Oct4, Sox2, and Nanog) and display the hallmark CSC properties of self-renewal/clonal formation and the ability to generate heterogeneous cell populations. Importantly, hyaluronan (HA) stimulates the CD44v3 (an HA receptor) interaction with Oct4-Sox2-Nanog leading to both a complex formation and the nuclear translocation of three CSC transcription factors. Further analysis reveals that microRNA-302 (miR-302) is controlled by an upstream promoter containing Oct4-Sox2-Nanog-binding sites, whereas chromatin immunoprecipitation (ChIP) assays demonstrate that stimulation of miR-302 expression by HA-CD44 is Oct4-Sox2-Nanog-dependent in HNSCC-specific CSCs. This process results in suppression of several epigenetic regulators (AOF1/AOF2 and DNMT1) and the up-regulation of several survival proteins (cIAP-1, cIAP-2, and XIAP) leading to self-renewal, clonal formation, and cisplatin resistance. These CSCs were transfected with a specific anti-miR-302 inhibitor to silence miR-302 expression and block its target functions. Our results demonstrate that the anti-miR-302 inhibitor not only enhances the expression of AOF1/AOF2 and DNMT1 but also abrogates the production of cIAP-1, cIAP-2, and XIAP and HA-CD44v3-mediated cancer stem cell functions. Taken together, these findings strongly support the contention that the HA-induced CD44v3 interaction with Oct4-Sox2-Nanog signaling plays a pivotal role in miR-302 production leading to AOF1/AOF2/DNMT1 down-regulation and survival of protein activation. All of these events are critically important for the acquisition of cancer stem cell properties, including self-renewal, clonal formation, and chemotherapy resistance in HA-CD44v3-activated head and neck cancer.

Hyaluronan-CD44 interaction promotes c-Src-mediated twist signaling, microRNA-10b expression, and RhoA/RhoC up-regulation, leading to Rho-kinase-associated cytoskeleton activation and breast tumor cell invasion.

Dysregulation of microRNAs is observed in many cancers, including breast cancer. In particular, miR-10b appears to play an important role in tumor cell invasion and breast cancer progression. In this study, we investigated hyaluronan (HA)-induced CD44 (a primary HA receptor) interaction with c-Src kinase and the transcriptional factor, Twist, in breast tumor cells (MDA-MB-231 cells). Our results indicate that HA binding to CD44 promotes c-Src kinase activation, which, in turn, increases Twist phosphorylation, leading to the nuclear translocation of Twist and transcriptional activation. Further analyses reveal that miR-10b is controlled by an upstream promoter containing the Twist binding site(s), whereas ChIP assays demonstrate that stimulation of miR-10b expression by HA/CD44-activated c-Src is Twist-dependent in breast tumor cells. This process results in the reduction of a tumor suppressor protein (HOXD10), RhoA/RhoC up-regulation, Rho-kinase (ROK) activation, and breast tumor cell invasion. Treatment of MDA-MB-231 cells with PP2 (a c-Src inhibitor) or Twist-specific siRNAs effectively blocks HA-mediated Twist signaling events, abrogates miR-10b production, and increases HOXD10 expression. Subsequently, this c-Src/Twist signaling inhibition causes down-regulation of RhoA/RhoC expression and impairment of ROK-regulated cytoskeleton function (e.g. tumor cell invasion). To further evaluate the role of miR-10b in RhoGTPase signaling, MDA-MB-231 cells were also transfected with a specific anti-miR-10b inhibitor in order to silence miR-10b expression and block its target functions. Our results demonstrate that anti-miR-10b inhibitor not only enhances HOXD10 expression but also abrogates HA/CD44-mediated tumor cell behaviors in breast tumor cells. Taken together, these findings indicate that the HA-induced CD44 interaction with c-Src-activated Twist plays a pivotal role in miR-10b production, leading to the down-regulation of tumor suppressor protein (HOXD10), RhoGTPase-ROK activation, and tumor cell invasion. All of these events are critical prerequisite steps for the acquisition of metastatic properties by human breast cancer cells.

The inhibition of miR-21 promotes apoptosis and chemosensitivity in ovarian cancer☆

BACKGROUND MicroRNAs have been implicated in tumorigenesis, drug resistance, and prognosis in cancer. We investigated the role of microRNA-21 (miR-21) in regulating ovarian cancer drug resistance. METHODS We used parental and cisplatin resistant ovarian cell lines to demonstrate the role of miR-21 in drug resistance and investigated the gene targets of miR-21. Fresh tumor specimens were used to validate our in vitro findings. RESULTS Cisplatin resistant ovarian cells were four-fold more resistant compared to the parental cell line. MiR-21 was overexpressed in the resistant cell line on microRNA microarray, which was subsequently validated with qRT-PCR. Using anti-microRNA inhibitors, we demonstrated that miR-21 attenuation reversed the drug resistant phenotype in both the resistant and parental cell lines. The inhibition of miR-21 induced apoptosis based on annexin V-FITC immunostaining. Using Western blot analysis, miR-21 knockdown enhanced the expression of tumor suppressor PDCD4, and attenuated apoptosis inhibitor c-IAP2. Using 101 specimens from advanced ovarian cancer patients enrolled in The Cancer Genome Atlas, we found that women with tumors that overexpressed miR-21 were associated with a shorter progression-free survival. CONCLUSION Our data suggest that miR-21 regulates drug resistance via apoptosis and cellular survival pathways. Targeting miR-21 may have clinical utility in the treatment of resistant ovarian cancer.

Interaction of low molecular weight hyaluronan with CD44 and toll-like receptors promotes the actin filament-associated protein 110-actin binding and MyD88-NFκB signaling leading to proinflammatory cytokine/chemokine production and breast tumor invasion.

Both high and low molecular weight hyaluronan (HMW‐HA vs. LMW‐HA) exist in various tissues and cells. In this study, we investigated LMW‐HA‐mediated CD44 interaction with Toll‐like receptors (TLRs), the actin filament‐associated protein (AFAP‐110), and a myeloid differentiation factor (MyD88) in breast tumor cells (MDA‐MB‐231 cells). Our data indicate that LMW‐HA (but not HMW‐HA) preferentially stimulates a physical association between CD44 and TLRs followed by a concomitant recruitment of AFAP‐110 and MyD88 into receptor‐containing complexes in breast tumor cells. LMW‐HA‐activated AFAP‐110 then binds to filamentous actin (F‐actin) resulting in MyD88/nuclear factor‐κB (NF‐κB) nuclear translocation, NF‐κB‐specific transcription, and target gene [interleukine 1β and interleukine‐8 (IL‐1β and IL‐8)] expression. These signaling events lead to proinflammatory cytokine/chemokine production in the breast tumor cells. AFAP‐110‐F‐actin (activated by LMW‐HA) also promotes tumor cell invasion. Downregulation of AFAP‐110 or MyD88 by transfecting breast tumor cells with AFAP‐110 siRNA or MyD88 siRNA, respectively not only blocks the ability of LMW‐HA to stimulate AFAP‐110‐actin function, but also impairs MyD88‐NF‐κB nuclear translocation and NF‐κB transcriptional activation. Consequently, both IL‐1β/IL‐8 production and tumor cell invasion are impaired. Taken together, these findings suggest that LMW‐HA plays an important role in CD44‐TLR‐associated AFAP‐110‐actin interaction and MyD88‐NF‐κB signaling required for tumor cell behaviors, which may contribute to the progression of breast cancer.

Role of hyaluronan synthase 2 to promote CD44-dependent oral cavity squamous cell carcinoma progression†

CD44 is a transmembrane receptor found on many different benign and malignant cells. Hyaluronan (HA), a major component of the extracellular matrix, is the primary ligand for CD44 receptors. In cancer cells, HA interaction with CD44 promotes multiple signaling pathways that influence tumor cell progression behaviors in a variety of solid tumors. Increasing evidence indicates that HA and CD44 signaling play an important role in oral cavity squamous cell carcinoma progression. HA is primarily synthesized by hyaluronan synthases, and the current study investigated the role of hyaluronan synthase 2 (HAS 2) in oral cavity carcinoma progression behaviors.

Activation of Matrix Hyaluronan-Mediated CD44 Signaling, Epigenetic Regulation and Chemoresistance in Head and Neck Cancer Stem Cells

Head and neck squamous cell carcinoma (HNSCC) is a solid tumor composed by a genotypically and phenotypically heterogeneous population of neoplastic cells types. High recurrence rate and regional metastases lead to major morbidity and mortality. Recently, many studies have focused on cellular and molecular mechanisms of tumor progression that can help to predict prognosis and to choose the best therapeutic approach for HNSCC patients. Hyaluronan (HA), an important glycosaminoglycan component of the extracellular matrix (ECM), and its major cell surface receptor, CD44, have been suggested to be important cellular mediators influencing tumor progression and treatment resistance in head and neck cancer. HNSCC contains a small subpopulation of cells that exhibit a hallmark of CD44-expressing cancer stem cell (CSC) properties with self-renewal, multipotency, and a unique potential for tumor initiation. HA has been shown to stimulate a variety of CSC functions including self-renewal, clone formation and differentiation. This review article will present current evidence for the existence of a unique small population of CD44v3highALDHhigh-expressing CSCs in HNSCC. A special focus will be placed on the role of HA/CD44-induced oncogenic signaling and histone methyltransferase, DOT1L activities in regulating histone modifications (via epigenetic changes) and miRNA activation. Many of these events are essential for the CSC properties such as Nanog/Oct4/Sox2 expression, spheroid/clone formation, self-renewal, tumor cell migration/invasion, survival and chemotherapeutic drug resistance in HA-activated head and neck cancer. These newly-discovered HA/CD44-mediated oncogenic signaling pathways delineate unique tumor dynamics with implications for defining the drivers of HNSCC progression processes. Most importantly, the important knowledge obtained from HA/CD44-regulated CSC signaling and functional activation could provide new information regarding the design of novel drug targets to overcome current therapeutic drug resistance which will have significant treatment implications for head and neck cancer patients.

Hyaluronan-CD44 interaction promotes HPV 16 E6 oncogene-mediated oropharyngeal cell carcinoma survival and chemoresistance

Head and neck squamous cell carcinoma (HNSCC) is a malignancy that often involves the oral cavity, pharynx, larynx, or paranasal sinuses. There is a compelling evidence of the human papilloma virus including HPV16 E6 oncogene drives cell transformation and oncogenic processes of HPV positive (HVP+) HNSCC [in particular, Oropharyngeal Squamous Cell Carcinoma (OPSCC)]. In this study, we determined that human OPSCC-derived, HPV16 E6+ cells (UMSCC-104 and UMSCC-47 cell lines) express CD44 and a regulatory transcription factor, c-Jun. Importantly, interaction between matrix hyaluronan (HA) and CD44 (an HA receptor) promotes c-Jun phosphorylation followed by phospho-c-Jun nuclear translocation and co-localization with HPV16 E6 in the nucleus of both UMSCC-104 and UMSCC-47 cells. Further analyses revealed that HPV16 E6 expression is regulated by an upstream promoter containing AP1/c-Jun binding site(s), and chromatin immunoprecipitation (ChIP) assays demonstrated that stimulation of HPV16 E6 expression by HA-CD44 interaction is phospho-c-Jun dependent in these HPV16+ UMSCC-104 and UMSCC-47 cells. This process results in an upregulation of survival proteins, inhibitors of the apoptosis family of proteins (IAPs) and chemoresistance in these HPV16+ cells. Treatment of UMSCC-104 or UMSCC-47 cells with c-Jun-specific or HPV16 E6-specific small interfering RNAs effectively blocks HA/CD44-mediated c-Jun signaling and abrogates HPV16 E6 expression as well as causes downregulation of survival proteins (cIAP-1 and cIAP-2) expression and enhancement of chemosensitivity. Together, these findings suggest that the HA/CD44-induced c-Jun signaling plays a pivotal role in HPV16 E6 upregulation leading to survival protein (cIAP-1/cIAP-2) production and chemoresistance in HPV16+ UMSCC-104 and UMSCC-47 cells. Most importantly, using a mouse xenograft model, we have observed that Cisplatin chemotherapy combined with the suppression of CD44, c-Jun and HPV16 E6 (by treating both UMSCC-104 cells and UMSCC-47 cells with CD44shRNA or c-Jun shRNA or HPV16 E6 shRNA) appears to be more effective in tumor size reduction than chemotherapy alone. Thus, these newly-discovered HA/CD44-c-Jun/HPV16E6 signaling pathways may provide new drug targets for overcoming cisplatin chemoresistance in HPV16E6-positive OPSCC cells.

Abstract 3861: Hyaluronan-CD44v3 interaction with oct4/sox2/nanog promotes miR-302 expression leading to self-renewal, clonal formation and cisplatin resistance in cancer stem cells from head and neck squamous cell carcinoma

Human Head and Neck Squamous Cell Carcinoma (HNSCC) is a highly malignant cancer associated with major morbidity and mortality. In this study we determined that human HNSCC-derived HSC-3 cells contain a subpopulation of cancer stem cells (CSCs) characterized by a high levels of CD44v3 and aldehyde dehydrogenase-1 (ALDH1) expression. These tumor cells also express several stem cell markers (the transcription factors-Oct4, Sox2 and Nanog) and display the hallmark CSC properties of self-renewal/clonal formation and the ability to generate heterogeneous cell populations. Importantly, hyaluronan (HA) stimulates the CD44v3 (an HA receptor) interaction with Oct4/Sox2/Nanog leading to both a complex formation and the nuclear translocation of three CSC transcription factors. Further analysis reveals that microRNA-302 (miR-302) is controlled by an upstream promoter containing Oct4/Sox2/Nanog binding sites, while chromatin immunoprecipitation (ChIP) assays demonstrate that stimulation of miR-302 expression by HA/CD44 is Oct4/Sox2/Nanog-dependent in HNSCC-specific CSCs. This process results in suppression of several epigenetic regulators (AOF1/AOF2 and DNMT1) and the upregulation of several survival proteins (cIAP-1, cIAP-2 and XIAP) leading to self-renewal, clonal formation and cisplatin resistance. These CSCs were transfected with a specific anti-miR-302 inhibitor in order to silence miR-302 expression and block its target functions. Our results demonstrate that the anti-miR-302 inhibitor not only enhances the expression of AOF1/AOF2 and DNMT1, but also abrogates the production of cIAP-1, cIAP-2 and XIAP and HA/CD44v3-mediated cancer stem cell functions. Taken together, these findings strongly support the contention that the HA-induced CD44v3 interaction with Oct4/Sox2/Nanog signaling plays a pivotal role in miR-302 production leading to AOF1/AOF2/DNMT1 downregulation and survival protein activation. All of these events are critically important for the acquisition of cancer stem cell properties including self-renewal, clonal formation and chemotherapy resistance in HA/CD44v3-activated head and neck cancer. Note: This abstract was not presented at the meeting. Citation Format: Lilly Y W Bourguignon, Gabriel Wong, Christine Earle. Hyaluronan-CD44v3 interaction with oct4/sox2/nanog promotes miR-302 expression leading to self-renewal, clonal formation and cisplatin resistance in cancer stem cells from head and neck squamous cell carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3861. doi:10.1158/1538-7445.AM2014-3861