Abstract 4612: SET overexpression is associated with recurrence-free survival in patients with primary breast cancer receiving adjuvant tamoxifen treatment

Background:

Estrogen receptor (ER) positive breast cancer accounts for 70% of breast cancer. Tamoxifen, a selective ER modulator, remains an important hormone therapeutic agent for patients with ER positive breast cancer. A number of patients receiving adjuvant tamoxifen still experience recurrence in the long term. In current study we explored the clinical significance of four biomarkers including SET, CIP2A, PP2A and Akt in ER positive breast cancer patients receiving adjuvant tamoxifen.

Methods:

Specimens were from ER positive breast cancer patients treated with adjuvant tamoxifen for a median of duration of 54.8 months with documented outcomes. The median follow-up was 106 months. Immunohistochemical staining for SET, CIP2A, p-PP2A (Tyr 307), p-Akt were performed and a H-score was assigned to quantify protein expression. In silico analysis of gene expression was evaluated from the public database KM plotter (available at: http://kmplot.com/analysis/). Human ER positive breast cancer cell line MCF7 cells were used for in vitro studies. MTT assay, flow cytometry and Western blot were used to assess the cells properties. Estrogen response element (ERE)-dependent luciferase activity was assessed by co-transfection of SET-expressing or control plasmids and 3⊆ERE bearing reporter plasmids into MCF7 cells and stimulated with estrogen.

Results:

In 218 primary ER positive breast cancer patients treated with adjuvant tamoxifen, 17 (7.8%) suffered from recurrence or metastasis. Higher expressions of SET and CIP2A by IHC analysis were associated with poor recurrence-free survival (RFS). Multivariate analysis revealed SET was independently correlated with worse RFS (Hazard ratio=3.72, 95% confidence interval 1.26-10.94, p=0.017). In silico, KM-plotter analysis revealed higher gene (mRNA) expressions of SET, PPP2CA and

Akt1 significantly correlated with worse RFS in breast cancer patients receiving adjuvant tamoxifen therapy. Because SET appeared to be the most prognostic for RFS among the four markers, we next explored the biological role in vitro. Tamoxifen exerted anti-proliferation and apoptotic effects in a dose-dependent manner of MCF7 cells. SET overexpression reduced tamoxifen-induced anti-proliferation in MCF-7 cells, in association with upregulated p-ER, suggesting that SET may affect ER pathway via the serine/threonine kinase PP2A. SET drove luciferase activity in an ERE-dependent manner, and also enhanced estrogen-promoted luciferase activity.

Conclusions:

Protein SET is a prognostic biomarker in ER positive breast cancer patients treated with tamoxifen and may contribute to tamoxifen resistance by modulating ER signaling pathway.

Citation Format: Yu-Hsiang Huang, Pei-Yi Chu, Ji-Lin Chen, Chun-Teng Huang, Chia-Han Lee, Ka-Yi Lau, Wan-Lun Wang, Yu-Ling Wang, Pei-Ju Lien, Ling-Ming Tseng, Chun-Yu Liu. SET overexpression is associated with recurrence-free survival in patients with primary breast cancer receiving adjuvant tamoxifen treatment [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 4612.

IFI44L is a novel tumor suppressor in human hepatocellular carcinoma affecting cancer stemness, metastasis, and drug resistance via regulating met/Src signaling pathway

BACKGROUND

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death worldwide. The disease recurrent rate is relatively high resulted in poor 5-year survival in advanced HCC. Cancer stem cells (CSCs) have been considered to be one of the main mechanisms for chemoresistance, metastasis, and recurrent disease. Interferon-induced protein 44-like (IFI44L) gene is a type I interferon-stimulated gene (ISG) and belongs to the IFI44 family. Previous reports indicated antiviral activity against HCV in IFI44L, however, its precise role and function in HCC has not been unveiled.

METHODS

To explore the characteristics of hepatic CSCs, we successfully enriched hepatic cancer stem-like cells from three established liver cancer cell lines (Hep3B, HepG2, and PLC lines). Parental Hep3B and HepG2 cells and their sphere cells were treated with doxorubicin for 48 h and cell viability was measured by MTT assay. HCC tissue blocks from 217 patients were sampled for tissue microarray (TMA). Follow-up information and histopathological and clinical data including age, gender, tumor grade, advanced stages, HBV, HCV, tumor number, tumor size, relapse-free survival, and overall survival were obtained from the cancer registry and medical charts. The liver TMA was evaluated for IFI44L expression using immunohistochemical staining and scores.

RESULTS

These hepatic cancer stem-like cells possess important cancer stemness characteristics including sphere-forming abilities, expressing important HCC cancer stem cell markers, and more chemoresistant. Interestingly, we found that overexpression of IFI44L decreased chemoresistance towards doxorubicin and knockdown of IFI44L restored chemoresistance as well as promoted sphere formation. Furthermore, we found that depletion of IFI44L enhanced migration, invasion, and pulmonary metastasis through activating Met/Src signaling pathway. Clinically, the expression level of IFI44L significantly reduced in HCC tumor tissues. Low expression of IFI44L levels also correlated with larger tumor size, disease relapse, advanced stages, and poor clinical survival in HCC patients.

CONCLUSION

Taken together, we first demonstrated that IFI44L is a novel tumor suppressor to affect cancer stemness, metastasis, and drug resistance via regulating Met/Src signaling pathway in HCC and can be serve as an important prognostic marker.

Molecular Regulation of Bone Metastasis Pathogenesis

Distant metastases are the major cause of mortality in cancer patients. Bone metastases may cause bone fractures, local pain, hypercalcemia, bone marrow aplasia, and spinal cord compression. Therefore, the management of bone metastases is important in cancer treatment. Normal bone remodeling is regulated by osteoprotegerin ligand (OPGL), receptor activator of NF-κB ligand (RANKL), parathyroid hormone-related protein (PTHrP), and other cytokines. In the tumor microenvironment, tumor cells induce a vicious cycle that promotes osteoblastic and osteolytic lesions. Studies support the idea that distant metastases may occur due to the immunosuppressive function of myeloid-derived suppressor cells (MDSCs). These cells inhibit T cells and natural killer (NK) cells and differentiate into tumor-associating macrophages (TAMs), monocytes, and dendritic cells (DCs). In this review, we summarize studies focusing on the role of MDSCs in bone metastasis and provide a strong foundation for developing anticancer immune treatments and anticancer therapies, in general.

Overexpression of regulator of G protein signaling 11 promotes cell migration and associates with advanced stages and aggressiveness of lung adenocarcinoma

Regulator of G protein signaling 11 (RGS11), a member of the R7 subfamily of RGS proteins, is a well-characterized GTPase-accelerating protein that is involved in the heterotrimeric G protein regulation of the amplitude and kinetics of receptor-promoted signaling in retinal bipolar and nerve cells. However, the role of RGS11 in cancer is completely unclear. Using subtractive hybridization analysis, we found that RGS11 was highly expressed in the lymph-node metastatic tissues and bone-metastatic tumors obtained from patients with lung adenocarcinoma. Characterization of the clinicopathological features of 91 patients showed that around 57.1% of the tumor samples displayed RGS11 overexpression that was associated with primary tumor status, nodal metastasis and increased disease stages. Its high expression was an independent predictive factor for poor prognosis of these patients. Cotransfection of guanine nucleotide-binding protein beta-5 (GNB5) markedly increased RGS11 expression. Enhancement or attenuation of RGS11 expression pinpointed its specific role in cell migration, but not in cell invasion and proliferation. Signaling events initiated by the RGS11–GNB5 coexpression activated the c-Raf/ERK/FAK-mediated pathway through upregulation of the Rac1 activity. Consistently, increasing the cell invasiveness of the transfectants by additional cotransfection of the exogenous urokinase–plasminogen activator gene caused a significant promotion in cell invasion in vitro and in vivo, confirming that RGS11 functions in cell migration, but requires additional proteolytic activity for cell and tissue invasion. Collectively, overexpression of RGS11 promotes cell migration, participates in tumor metastasis, and correlates the clinicopathological conditions of patients with lung adenocarcinoma.

Lysine demethylase 2A promotes stemness and angiogenesis of breast cancer by upregulating Jagged1

Alterations of histone methylation dynamically regulated by methyltransferases and demethylases are frequently found in human cancers. Here, we showed that expression of lysine demethylase 2A (KDM2A) is markedly increased in human breast cancer and its overexpression is associated with tumor progression and poor prognosis. Knockdown of KDM2A in breast cancer cells reduced proliferation but not viability. Gene set enrichment analysis revealed that inhibition of KDM2A down-regulates angiogenic genes with concurrent reduction of Jagged1 (JAG1), NOTCH1 and HEY1 in the NOTCH signaling. Chromatin immunoprecipitation- quantitative polymerase chain reaction (ChIP-qPCR) demonstrated the binding of KDM2A to the JAG1 promoter and the increase of methylation of Lys-36 of histone H3 (H3K36) in KDM2A-depleted MDA-MB-231 cells. Tumorsphere formation was significantly reduced in KDM2A-depleted cells which could be reversed by ectopic expression of JAG1. A selective KDM2A inhibitor daminozide also decreased the number of tumorsphere and the number of CD24-/CD44hi cells. In addition, daminozide acted synergistically with cisplatin in cell killing. We identified SOX2 as a direct transcriptional target of KDM2A to promote cancer stemness. Depletion of KDM2A in MDA-MB-231 cells attenuated NOTCH activation and tube formation in co-cultured endothelial cells. Two pro-angiogenic factors JAG1 and PDGFA are key mediators for KDM2A to enhance angiogenesis. Finally, inhibition of KDM2A significantly decreased tumor growth and angiogenesis in orthotopic animal experiments. Collectively, we conclude that KDM2A functions as an oncogene in breast cancer by upregulating JAG1 to promote stemness, chemoresistance and angiogenesis.

Glycyrrhizic acid induces human MDA-MB-231 breast cancer cell death and autophagy via the ROS-mitochondrial pathway

Glycyrrhizic acid (GA), the main component of licorice root extracts, has been shown to suppress cell proliferation and induce apoptosis in various types of cancers. However, the molecular mechanism of its anticancer activity remains poorly understood and warrants further investigation. MDA-MB‑231 cells were treated with various concentrations of GA and the cytotoxic effects of GA were determined using the CCK-8 assay. Apoptosis and cell cycle status were detected by flow cytometry. Reactive oxygen species (ROS) levels and mitochondrial membrane potential (∆Ψm) were assessed using DCFDA, MitoSOX and JC-1 staining. Western blot analysis was used to quantify the expression of autophagy-related proteins. In the present study, induction of autophagic cell death was observed in GA-treated MDA-MB‑231 cells. Downregulation of p62- and beclin 1-associated proteins occurred after GA treatment, and, the conversion of LC3 and increased ROS without significant changes in caspase‑associated proteins and intracellular responses were detected. Furthermore, loss of mitochondria and its membrane potential in cells demonstrated that mitochondria were involved in the GA-regulated MDA-MB-231 cell death. The addition of a pan-caspase inhibitor (z-VAD-fmk) did not suppress the GA-induced apoptotic effect, and GA-induced apoptosis was not accompanied by processing of procaspase-8, -9 and -3. However, GA triggered the translocation of the apoptosis-inducing factor (AIF) from the mitochondria into the nucleus. In contrast, GA-induced LC3 conversion was significantly inhibited by 3 methlyadenine (3MA), an inhibitor of PI3K‑regulated autophagy. Therefore, these results suggest that enhancement of both AIF- and LC3-dependent GA-derived ROS generation plays an important role in the inhibition of the growth of MDA-MB-231 human breast cancer cells.

Feasibility of deep brain stimulation for controlling the lower urinary tract functions: An animal study

OBJECTIVE

To evaluate the feasibility of deep brain stimulation (DBS) and compare the potential of four DBS targets in rats for regulating bladder activity: the periaqueductal gray (PAG), locus coeruleus (LC), rostral pontine reticular nucleus (PnO), and pedunculopontine tegmental nucleus (PPTg).

METHODS

A bipolar stimulating electrode was implanted. The effects of DBS on the inhibition and activation of micturition reflexes were investigated by using isovolumetric intravesical pressure recordings.

RESULTS

PAG DBS at 2-2.5 V, PnO DBS at 2-2.5 V, and PPTg DBS at 1.75-2.5 V nearly completely inhibited reflexive isovolumetric bladder contractions. By contrast, LC DBS at 1.75 and 2 V slightly augmented reflexive isovolumetric bladder contractions in rats. DBSs on PnO and PPTg at higher intensities (2.5-5 V) demonstrated a higher success rate and larger contraction area evocation in activating bladder contractions in a partially filled bladder. DBS targeting the PPTg was most efficient in suppressing reflexive isovolumetric bladder contractions.

CONCLUSION

PPTg DBS demonstrated stable results and high potency for controlling bladder contractions. PPTg might be a promising DBS target for developing new neuromodulatory approaches for the treatment of bladder dysfunctions.

SIGNIFICANCE

DBS could be a potential approach to manage bladder function under various conditions.

A 3-year surveillance on causes of death or reasons for euthanasia of domesticated dogs in Taiwan

Over the last 2 decades, there has been growing interest in research on the mortality of domesticated pets. These studies relied on an effective data-collecting system. During 2012-2014, a real-time reporting system was designed for mortality data in owned dogs and cats. The present retrospective study aimed to report on the causes of death (CODs) or reasons for euthanasia (RFEs) in domesticated dogs in Taiwan, and to investigate CODs/RFEs segregated by demographic variables. Data from 2306 domesticated dogs were acquired during the 3-year period in the present study. The median age at death of the study population was 10.2 years (median interquartile range 7.0-14.0; range 0.0-25.0). Crossbred, female, and neutered dogs showed greater ages at death than other groups. The most common COD/RFE was neoplasia, followed by multiple organ involvement (MOI) and cardiovascular diseases. Segregated by cut-off ages, the most common COD/RFE was infection among dogs younger than 3 years or 1year, and neoplasia among dogs at or older than 3 years or 1year of age; the most common COD/RFE was neoplasia among dogs younger than median age, and MOI among dogs at or older than median age. Segregated by geographic variables, the ranking and frequency of CODs/RFEs displayed different patterns between the capital city/non-capital areas, and among areas stratified by human population densities. The study provides various insights into age at death and CODs/RFEs in owned-dog population in Taiwan, and provides new directions for future research.

New Insights into the Role of Inflammation in the Pathogenesis of Atherosclerosis

Atherosclerosis is a chronic inflammatory disease characterized by the accumulation of lipids, smooth muscle cell proliferation, cell apoptosis, necrosis, fibrosis, and local inflammation. Immune and inflammatory responses have significant effects on every phase of atherosclerosis, and increasing evidence shows that immunity plays a more important role in atherosclerosis by tightly regulating its progression. Therefore, understanding the relationship between immune responses and the atherosclerotic microenvironment is extremely important. This article reviews existing knowledge regarding the pathogenesis of immune responses in the atherosclerotic microenvironment, and the immune mechanisms involved in atherosclerosis formation and activation.

The regulatory role of aberrant Phosphatase and Tensin Homologue and Liver Kinase B1 on AKT/mTOR/c-Myc axis in pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumor (pNET) is an uncommon type of pancreatic neoplasm. Low Phosphatase and Tensin Homologue (PTEN) expression and activation of the mechanistic target of rapamycin (mTOR) pathway have been noted in pNETs, and the former is associated with poor survival in pNET patients. Based on the results of the RADIANT-3 study, everolimus, an oral mTOR inhibitor, has been approved to treat advanced pNETs. However, the exact regulatory mechanism for the mTOR pathway in pNETs remains largely unknown. PTEN and liver kinase B1 (LKB1) are well-known for their regulatory role in the mTOR pathway. We evaluated the expression of PTEN and LKB1 in 21 pNET patients, and low PTEN and LKB1 expression levels were noted in 48% and 24% of the patients, respectively. Loss of PTEN and LKB1 synergistically promoted cell proliferation of pNET, attenuated the sensitivity of cells to mTOR inhibitors and enhanced c-Myc expression, which back-regulated PTEN, AKT, mTOR and its downstream effectors. For pNET cells with low expression levels of PTEN and LKB1, silencing the expression of c-Myc by shRNA reduced their proliferative rate, while adding either c-Myc inhibitor or AMP-activated protein kinase activator reversed their resistance to mTOR inhibitors in vitro and in vivo. Furthermore, high c-Myc expression was subsequently identified in 81% of pNETs, suggesting that up-regulation of c-Myc expression in pNETs may occur through PTEN/LKB1-dependent and PTEN/LKB1-independent regulation. The results delineated the regulation of PTEN and LKB1 on the AKT/mTOR/c-Myc axis and suggested that both c-Myc and mTOR are potential therapeutic targets for pNET.

New Insights into the Role of Autophagy in Tumor Immune Microenvironment

The tumor microenvironment is a complex system that is affected by various factors, including hypoxia, acidosis, and immune and inflammatory responses, which have significant effects on tumor adhesion, invasion, metastasis, angiogenesis, and autophagy. In this hostile tumor microenvironment, autophagy of tumor cells can promote tumor growth and metastasis. As autophagy is a double-edged sword in tumors, treatment of cancer via regulation of autophagy is extremely complicated. Therefore, understanding the relationship between tumor autophagy and the tumor microenvironment is extremely important. As the immune milieu plays an important role in tumor development, immunotherapy has become a promising form of cancer therapy. A multi-pronged treatment approach using immunotherapy and molecular targets may become the major direction for future cancer treatments. This article reviews existing knowledge regarding the immune factors in the tumor microenvironment and the status of tumor autophagy research.

The effects of the location of cancer stem cell marker CD133 on the prognosis of hepatocellular carcinoma patients

BACKGROUND

CD133 (prominin-1) is widely believed to be a cancer stem cell marker in various solid tumor types, and CD133 has been correlated with tumor-initiating capacity. Recently, the nuclear location of CD133 expression in tumors has been discussed, but hepatocellular carcinoma (HCC) has not been included in these discussions. The goal of this study was to investigate the location of CD133 expression in HCC and this location's potential value as a prognostic indicator of survival in patients with HCC.

METHODS

We enrolled 119 cancerous tissues and pair-matched adjacent normal liver tissue from HCC patients. These tissues were obtained immediately after operation, and tissue microarrays were subsequently constructed. The expression of CD133 was measured by immunohistochemistry (IHC), and the correlations between this expression and clinical characteristics and prognosis was estimated using statistical analysis.

RESULTS

The results showed that the CD133 protein expression levels of HCC in both the cytoplasm and nucleus were significantly higher than adjacent normal liver tissue. Kaplan-Meier survival and Cox regression analyses revealed that high CD133 expression in the cytoplasm was an independent predictor of poor prognosis for the overall survival (OS) and relapse-free survival (RFS) rates of HCC patients (P = 0.028 and P = 0.046, respectively). Surprisingly, high nuclear CD133 expression of HCC was an independent predictor of the good prognosis of the OS and RFS rates of HCC patients (P = 0.023 and P = 0.012, respectively).

CONCLUSIONS

The clinical evidence that revealed cytoplasmic CD133 expression was correlated with poor prognosis, while nuclear CD133 expression was significantly correlated with favorable prognosis.

Abstract 4192: Targeting SHP-1/p-Lyn signaling shows therapeutic potential in diffuse large B-cell lymphoma

Background:

Diffuse large B cell lymphoma (DLBCL) is one aggressive form of non-Hodgkin’s lymphoma. Genetic analyses revealed molecular heterogeneity of DLBCL tumors, classifying the cell-of-origin into two distinct molecular subtypes: germinal center B-cell (GCB) and activated B-cell (ABC). ABC-type DLBCL has a worse survival after upfront chemotherapy compared to GCB-type DLBCL, thus ABC-type DLBCL patients have an unmet medical need that warrants additional research efforts and new therapeutic options. In current study we explored the biological role and potential therapeutic implication of a protein phosphatase SHP-1 in DLBCL.

Methods:

DLBCL cell lines including ABC-like cell lines U2932, Ly-3 and GC-like cell lines DHL-6, Ly-7 and DB were used for in vitro studies. Cell viability was examined by MTT assay. Apoptotic effects were examined by flow cytometry and Western blot. Signal transduction pathways in cells were assessed by Western blot. In vivo therapeutic testing of SHP-1 agonists were performed in nude mice with DLBCL xenografts.

Results:

We first examined the protein expression of SHP-1 and its downstream p-STAT3 in a panel of DLBCL cell lines, and identified in general SHP-1/p-STAT3 expression was higher in ABC-like cells. Interestingly, the expressions of p-Lyn (Tyr396), p-BTK (Tyr223), key members of B-cell receptor (BCR) signaling pathway, were also higher in ABC-like cells. Knockdown or overexpression of SHP-1 protein expression revealed a reciprocal change of p-Lyn, suggesting SHP-1 negatively regulates phosphorylation of Lyn kinase. Immunoprecipitation experiments confirmed SHP-1 interact with Lyn in DLBCL cells. We previously developed direct SHP-1 agonists, namely SC-43 and SC-60, which could increase SHP-1 activities and induce apoptosis. Here we tested SC-43 and SC-60 in comparison to ibrutinib, a selective Bruton's tyrosine kinase (BTK) inhibitor. The SHP-1 agonists showed in general superior anti-proliferative and apoptotic effects, comparing to ibrutinib. Mechanistically, SHP-1 agonists enhanced SHP-1 activity, decreased BCR signaling p-Lyn and p-BTK, which led to apoptosis. In addition, SHP-1 agonists also down-regulated p-STAT3 as previously reported, which also contributes to anti-cancer effects. In vivo, SC-43 at doses of 10mg/kg/day and 30mg/kg/day orally showed comparable anti-tumor effects with ibrutinib at doses of 12.5 mg/kg/day and 25 mg/kg/day in mice bearing U2932 xenografts, respectively. Western blot confirmed SC-43 downregulation on p-Lyn and p-BTK in vivo.

Conclusions:

SHP-1 negatively regulates phosphorylation of Lyn, and targeting SHP-1/p-Lyn with direct SHP-1 agonists shows therapeutic potential in DLBCL.

Citation Format: Chun-Yu Liu, Man-Hsin Hung, Ming-Hsien Tsai, Pei-Yi Chu, Tzu-Ting Huang, Chun-Teng Huang, Chung-Wai Shiau, Kuen-Feng Chen. Targeting SHP-1/p-Lyn signaling shows therapeutic potential in diffuse large B-cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4192. doi:10.1158/1538-7445.AM2017-4192

Sequential combination of docetaxel with a SHP-1 agonist enhanced suppression of p-STAT3 signaling and apoptosis in triple negative breast cancer cells

Triple negative breast cancer (TNBC) is an aggressive cancer for which prognosis remains poor. Combination therapy is a promising strategy for enhancing treatment efficacy. Blockade of STAT3 signaling may enhance the response of cancer cells to conventional chemotherapeutic agents. Here we used a SHP-1 agonist SC-43 to dephosphorylate STAT3 thereby suppressing oncogenic STAT3 signaling and tested it in combination with docetaxel in TNBC cells. We first analyzed messenger RNA (mRNA) expression of SHP-1 gene (PTPN6) in a public TNBC dataset (TCGA) and found that higher SHP-1 mRNA expression is associated with better overall survival in TNBC patients. Sequential combination of docetaxel and SC-43 in vitro showed enhanced anti-proliferation and apoptosis associated with decreased p-STAT3 and decreased STAT3-downstream effector cyclin D1 in the TNBC cell lines MDA-MB-231, MDA-MB-468, and HCC-1937. Ectopic expression of STAT3 reduced the increased cytotoxicity induced by the combination therapy. In addition, this sequential combination showed enhanced SHP-1 activity compared to SC-43 alone. Furthermore, the combination treatment-induced apoptosis was attenuated by small interfering RNA (siRNA) against SHP-1 or by ectopic expression of SHP-1 mutants that caused SC-43 to lose its SHP-1 agonist capability. Moreover, combination of docetaxel and SC-43 showed enhanced tumor growth inhibition compared to single-agent therapy in mice bearing MDA-MB-231 tumor xenografts. Our results suggest that the novel SHP-1 agonist SC-43 enhanced docetaxel-induced cytotoxicity by SHP-1 dependent STAT3 inhibition in human triple negative breast cancer cells. TNBC patients with high SHP-1 expressions show better survival. Docetaxel combined with SC-43 enhances cell apoptosis and reduces p-STAT3. SHP-1 inhibition reduces the enhanced effect of docetaxel-SC-43 combination. Docetaxel-SC-43 combination suppresses xenograft tumor growth and reduces p-STAT3.

KEY MESSAGES

TNBC patients with high SHP-1 expressions show better survival. Docetaxel combined with SC-43 enhances cell apoptosis and reduces p-STAT3. SHP-1 inhibition reduces the enhanced effect of docetaxel-SC-43 combination. Docetaxel-SC-43 combination suppresses xenograft tumor growth and reduces p-STAT3.

Palbociclib induces activation of AMPK and inhibits hepatocellular carcinoma in a CDK4/6-independent manner

Palbociclib, a CDK4/6 inhibitor, has recently been approved for hormone receptor‐positive breast cancer patients. The effects of palbociclib as a treatment for other malignancies, including hepatocellular carcinoma (HCC), are of great clinical interest and are under active investigation. Here, we report the effects and a novel mechanism of action of palbociclib in HCC. We found that palbociclib induced both autophagy and apoptosis in HCC cells through a mechanism involving 5′ AMP‐activated protein kinase (AMPK) activation and protein phosphatase 5 (PP5) inhibition. Blockade of AMPK signals or ectopic expression of PP5 counteracted the effect of palbociclib, confirming the involvement of the PP5/AMPK axis in palbociclib‐mediated HCC cell death. However, CDK4/6 inhibition by lentivirus‐mediated shRNA expression did not reproduce the effect of palbociclib‐treated cells, suggesting that the anti‐HCC effect of palbociclib is independent of CDK4/6. Moreover, two other CDK4/6 inhibitors (ribociclib and abemaciclib) had minimal effects on HCC cell viability and the PP5/AMPK axis. Palbociclib also demonstrated significant tumor‐suppressive activity in a HCC xenograft model, which was associated with upregulation of pAMPK and PP5 inhibition. Finally, we analyzed 153 HCC clinical samples and found that PP5 expression was highly tumor specific and was associated with poor clinical features. Taken together, we conclude that palbociclib exerted antitumor activity against HCC through the PP5/AMPK axis independent of CDK4/6. Our findings provide a novel mechanistic basis for palbociclib and reveal the therapeutic potential of targeting PP5/AMPK signaling with a PP5 inhibitor for the treatment of hepatocellular carcinoma.

The prevalence rate of deviations in body constitutions and related factors in follow-up stage breast cancer patients-A nationwide study

OBJECTIVES

The aim of this study was to apply a rigorous traditional Chinese medicine (TCM) body constitution questionnaire (BCQ) to survey the prevalence rate of deviations in body constitution and to explore the health-related lifestyle behavior factors of deviations in body constitution.

DESIGN

A cross-sectional study was administered through postal mail. Subjects were recruited from a national organization for breast cancer patients (Taiwan Breast Cancer Alliance).

SETTING/MAIN OUTCOME MEASURES

Data were obtained from 311 breast cancer patients by questionnaires including a demographic record sheet, lifestyle behavior scales and the BCQ (Yang-Xu, Yin-Xu, and Stasis). Differences concerning the presence of body constitutions were analyzed by Chi-square tests and analyses of variance, and potential predictive factors were analyzed using multivariate logistic regression.

RESULTS

In total, 55.3% of the subjects had a Yang-Xu constitution, 61.0% had a Yin-Xu constitution, and 47.6% had a Stasis constitution. A total of 42.8% of the patients displayed a combination of the three types of body constitutions. Feeling stressed, physical exercise, and favoring fried food were predictors of the combined Yang-Xu, Yin-Xu and Stasis constitutions (p<0.05). Staying up late was significantly associated with Yin-Xu (p=0.017), and favoring salty food was significantly associated with Stasis (p=0.019).

CONCLUSIONS

A high prevalence of deviations in body constitutions was observed in the follow-up stage of breast cancer patients. Increasing the adherence to healthy lifestyle behaviors might strengthen and balance body constitution, which could improve supportive care in breast cancer survivors.

Carfilzomib induces leukaemia cell apoptosis via inhibiting ELK1/KIAA1524 (Elk-1/CIP2A) and activating PP2A not related to proteasome inhibition

Enhancing the tumour suppressive activity of protein phosphatase 2A (PP2A) has been suggested to be an anti-leukaemic strategy. KIAA1524 (also termed CIP2A), an oncoprotein inhibiting PP2A, is associated with disease progression in chronic myeloid leukaemia and may be prognostic in cytogenetically normal acute myeloid leukaemia. Here we demonstrated that the selective proteasome inhibitor, carfilzomib, induced apoptosis in sensitive primary leukaemia cells and in sensitive leukaemia cell lines, associated with KIAA1524 protein downregulation, increased PP2A activity and decreased p-Akt, but not with the proteasome inhibition effect of carfilzomib. Ectopic expression of KIAA1524, or pretreatment with the PP2A inhibitor, okadaic acid, suppressed carfilzomib-induced apoptosis and KIAA1524 downregulation in sensitive cells, whereas co-treatment with the PP2A agonist, forskolin, enhanced carfilzomib-induced apoptosis in resistant cells. Mechanistically, carfilzomib affected KIAA1524 transcription through disturbing ELK1 (Elk-1) binding to the KIAA1524 promoter. Moreover, the drug sensitivity and mechanism of carfilzomib in xenograft mouse models correlated well with the effects of carfilzomib on KIAA1524 and p-Akt expression, as well as PP2A activity. Our data disclosed a novel drug mechanism of carfilzomib in leukaemia cells and suggests the potential therapeutic implication of KIAA1524 in leukaemia treatment.

Down-regulation of RASA1 Is Associated with Poor Prognosis in Human Hepatocellular Carcinoma

BACKGROUND/AIM

RASA1 (p120RasGAP), encodes Ras GTPase-activating protein 1 and, is a potent tumor suppressor gene that is frequently inactivated in several human cancer types. However, its precise role in hepatocellular carcinoma (HCC) has been blurred.

MATERIALS AND METHODS

We hypothesized that RASA1 plays a crucial role in tumor pathogenesis and progression of HCC. RASA1 expression levels were analyzed in 226 cases of HCC by immunohistochemistry.

RESULTS

It was found that 38.68% (41/106) of the high-grade HCC samples and 54.17% (65/120) of the low-grade HCC samples expressed RASA1 protein. The difference between RASA1 expression in high-grade and low-grade HCC was statistically significant (p=0.02). Additionally, RASA1 high expression was inversely associated with larger tumor size (p<0.001). Although RASA1 is known as a tumor suppressor, its role in overall survival (OS) in HCC is unclear. Kaplan-Meier survival analysis showed that patients with low level of RASA1 expression correlated with a significantly poorer survival compared to those with high level of RASA1 expression.

CONCLUSION

These data support that RASA1 could serve as an independent prognostic marker for HCC patients.

Lapatinib inhibits CIP2A/PP2A/p-Akt signaling and induces apoptosis in triple negative breast cancer cells

We tested the efficacy of lapatinib, a dual tyrosine kinase inhibitor which interrupts the HER2 and epidermal growth factor receptor (EGFR) pathways, in a panel of triple-negative breast cancer (TNBC) cells, and examined the drug mechanism. Lapatinib showed an anti-proliferative effect in HCC 1937, MDA-MB-468, and MDA-MB-231 cell lines. Lapatinib induced significant apoptosis and inhibited CIP2A and p-Akt in a dose and time-dependent manner in the three TNBC cell lines. Overexpression of CIP2A reduced lapatinib-induced apoptosis in MDA-MB-468 cells. In addition, lapatinib increased PP2A activity (in relation to CIP2A inhibition). Moreover, lapatinib-induced apoptosis and p-Akt downregulation was attenuated by PP2A antagonist okadaic acid. Furthermore, lapatinib indirectly decreased CIP2A transcription by disturbing the binding of Elk1 to the CIP2A promoter. Importantly, lapatinib showed anti-tumor activity in mice bearing MDA-MB-468 xenograft tumors, and suppressed CIP2A as well as p-Akt in these xenografted tumors. In summary, inhibition of CIP2A determines the effects of lapatinib-induced apoptosis in TNBC cells. In addition to being a dual tyrosine kinase inhibitor of HER2 and EGFR, lapatinib also inhibits CIP2A/PP2A/p-Akt signaling in TNBC cells.