Targeting cancer stemness mediated by BMI1 and MCL1 for non-small cell lung cancer treatment.

Lung cancer is the leading cause of cancer-associated death, with a global 5-year survival rate <20%. Early metastasis and recurrence remain major challenges for lung cancer treatment. The stemness property of cancer cells has been suggested to play a key role in cancer plasticity, metastasis and drug-resistance, and is a potential target for drug development. In this study, we found that in non-small cell lung cancer (NSCLC), BMI1 and MCL1 play crucial roles of cancer stemness including invasion, chemo-resistance and tumour initiation. JNK signalling serves as a link between oncogenic pathway or genotoxicity to cancer stemness. The activation of JNK, either by mutant EGFR or chemotherapy agent, stabilized BMI1 and MCL1 proteins through suppressing the expression of E3-ubiquitin ligase HUWE1. In lung cancer patient samples, high level of BMI1 is correlated with poor survival, and the expression of BMI1 is positively correlated with MCL1. A novel small-molecule, BI-44, was developed, which effectively suppressed BMI1/MCL1 expressions and inhibited tumour formation and progression in preclinical models. Targeting cancer stemness mediated by BMI1/MCL1 with BI-44 provides the basis for a new therapeutic approach in NSCLC treatment.

Impact Position Estimation for Baseball Batting with a Force-Irrelevant Vibration Feature.

In this work we propose a novel method for impact position estimation during baseball batting, which is independent of impact intensity, i.e., force-irrelevant. In our experiments, we mount a piezoelectric vibration sensor on the knob of a wooden bat to record: (1) 3600 vibration signals (waveforms) from ball-bat impacts in the static experiment-30 impacts from each of 40 positions (distributed 1-40 cm from the end of the barrel) and 3 intensities (drop heights at 75, 100, and 125 cm, resp.), and (2) 45 vibration signals from actual battings by three baseball players in the dynamic experiment. The results show that the peak amplitude of the signal in the time domain, and the peaks of the first, second, and third eigenfrequencies (EFs) of the bat all increase with the impact intensity. However, the ratios of peaks at these three EFs (1st/2nd, 2nd/3rd, and 1st/3rd) hardly change with the impact intensity, and the observation is consistent for both the static and dynamic experiments across all impact positions. In conclusion, we have observed that the ratios of peaks at the first three EFs are a force-irrelevant feature, which can be used to estimate the impact position in baseball batting.

Stabilization of AURKA by the E3 ubiquitin ligase CBLC in lung adenocarcinoma.

CBL family proteins (CBL, CBLB and CBLC in mammals) are E3 ubiquitin ligases of protein tyrosine kinases. CBL mediates the lysosomal degradation of activated EGFR through K63-linked ubiquitination, while CBLC has an oncogenic function by positively regulating EGFR activation through K6 and K11-linked ubiquitination in EGFR mutant lung adenocarcinoma (LAD). Here, we used immunoprecipitation and mass spectrometry to study the CBLC interactome, and found that CBLC is also involved in cell cycle regulation by stabilizing Aurora kinase A (AURKA). CBLC interacted with the kinase domain of AURKA and positively regulated the stability of AURKA by conjugating monoubiquitination and K11/K63-linked polyubiquitination, which are protective from degrading K11/K48 polyubiquitination. CBLC depletion markedly decreased the half-life of AURKA in cycloheximide-treated LAD cells. When LAD cells were synchronized with double thymidine block at the G1/S boundary and then released into mitotic arrest, CBLC depletion delayed the accumulation and activation of AURKA and prevented cancer cells from entering mitosis. CBLC deficiency significantly delayed cell cycle progression, reduced the mitotic population, and increased apoptosis of LAD cells. Targeting CBLC inhibited tumor growth of LAD cells and enhanced their sensitivity to paclitaxel in xenograft models. Immunohistochemical staining of the tissue microarray also revealed a positive correlation between the expression of CBLC and AURKA in normal and LAD tissues, further supporting the positive regulation of AURKA expression by CBLC. In summary, these findings indicate that the oncogenic E3 ligase CBLC plays a role in mitotic entry by stabilizing AURKA via ubiquitination in LAD. This work demonstrates that targeting CBLC combined with paclitaxel might be a potential option for the treatment of LAD patients who have no available targeted therapies.

AGEs-Induced Calcification and Apoptosis in Human Vascular Smooth Muscle Cells Is Reversed by Inhibition of Autophagy.

Vascular calcification (VC) in macrovascular and peripheral blood vessels is one of the main factors leading to diabetes mellitus (DM) and death. Apart from the induction of vascular calcification, advanced glycation end products (AGEs) have also been reported to modulate autophagy and apoptosis in DM. Autophagy plays a role in maintaining the stabilization of the external and internal microenvironment. This process is vital for regulating arteriosclerosis. However, the internal mechanisms of this pathogenic process are still unclear. Besides, the relationship among autophagy, apoptosis, and calcification in HASMCs upon AGEs exposure has not been reported in detail. In this study, we established a calcification model of SMC through the intervention of AGEs. It was found that the calcification was upregulated in AGEs treated HASMCs when autophagy and apoptosis were activated. In the country, AGEs-activated calcification and apoptosis were suppressed in Atg7 knockout cells or pretreated with wortmannin (WM), an autophagy inhibitor. These results provide new insights to conduct further investigations on the potential clinical applications for autophagy inhibitors in the treatment of diabetes-related vascular calcification.

Alisertib inhibits migration and invasion of EGFR-TKI resistant cells by partially reversing the epithelial-mesenchymal transition.

Epithelial growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have been widely used in the clinical treatment of non-small cell lung cancer (NSCLC) patients with EGFR mutations. Previous studies have shown that Aurora kinase A (AURKA) is overexpressed in a broad spectrum of cancer cells, which can induce epithelial-mesenchymal transition (EMT) and contribute to the occurrence of acquired EGFR-TKI resistance. However, whether the inhibition of AURKA could overcome EGFR-TKI resistance or reverse the EMT in TKI-resistant NSCLC cells remains unclear. In the current study, we established three EGFR-TKI-resistant cell lines and analyzed their expression profiles by RNA sequencing. The results revealed that the EMT pathway is significantly upregulated in the three cell lines with EGFR-TKI resistance. The phosphorylation of AURKA at Thr 288 was also upregulated, suggesting that the activation of AURKA plays an important role in the occurrence of EGFR-TKI resistance. Interestingly, the AURKA inhibitor, alisertib treatment restored the susceptibility of resistant cells to EGFR-TKIs and partially reversed the EMT process, thereby reducing migration and invasion in EGFR-TKI-resistant cells. This study provides evidence that targeting AURKA signaling pathway by alisertib may be a novel approach for overcoming EGFR-TKI resistance and for the treatment of metastatic EGFR-TKIs in NSCLC patients.

TAZ negatively regulates the novel tumor suppressor ANKRD52 and promotes PAK1 dephosphorylation in lung adenocarcinomas.

Lung cancer is the leading cause of cancer death, and therefore the discovery of novel therapeutic targets is crucial. P21-activated kinase (PAK1) is an important oncogene involved in the signaling of actin cytoskeleton organization. Although PAK1 inhibition has been shown to suppress cancer progression, specific PAK1 inhibitors are not available due to the complex structure and insufficient understanding of this kinase. The Hippo signaling effector TAZ is known to be elevated in multiple human cancers and to promote cancer metastasis. This study aimed to explore the role of TAZ in regulating the tumor suppressor ankyrin repeat domain 52 (ANKRD52) and PAK1 activity. A negative correlation between TAZ and ANKRD52 was observed, with knockdown of TAZ leading to enhanced ANKRD52 promoter activity and increased mRNA levels. Moreover, reduced ANKRD52 levels were associated with late-stage lung cancer. Knockdowns of ANKRD52 resulted in elevated cell mobility, while forced ANKRD52 expression attenuated cell mobility. ANKRD52 is a subunit of the protein phosphatase 6 (PP6) holoenzyme. Mass spectrometry analysis revealed the interaction between PAK1 and the ANKRD52-PP6 complex. Knockdown of ANKRD52 or PP6c resulted in upregulated PAK1 phosphorylation. Our study demonstrates that the novel tumor suppressor protein ANKRD52 is transcriptionally inhibited by TAZ, regulating cell mobility through interactions with PP6c and dephosphorylation of PAK1.

Low-Dose Nicotine Activates EGFR Signaling via α5-nAChR and Promotes Lung Adenocarcinoma Progression.

Nicotine in tobacco smoke is considered carcinogenic in several malignancies including lung cancer. The high incidence of lung adenocarcinoma (LAC) in non-smokers, however, remains unexplained. Although LAC has long been less associated with smoking behavior based on previous epidemiological correlation studies, the effect of environmental smoke contributing to low-dose nicotine exposure in non-smoking population could be underestimated. Here we provide experimental evidence of how low-dose nicotine promotes LAC growth in vitro and in vivo. Screening of nicotinic acetylcholine receptor subunits in lung cancer cell lines demonstrated a particularly high expression level of nicotinic acetylcholine receptor subunit α5 (α 5-nAChR) in LAC cell lines. Clinical specimen analysis revealed up-regulation of α 5-nAChR in LAC tumor tissues compared to non-tumor counterparts. In LAC cell lines α 5-nAChR interacts with epidermal growth factor receptor (EGFR), positively regulates EGFR pathway, enhances the expression of epithelial-mesenchymal transition markers, and is essential for low-dose nicotine-induced EGFR phosphorylation. Functionally, low-dose nicotine requires α 5-nAChR to enhance cell migration, invasion, and proliferation. Knockdown of α 5-nAChR inhibits the xenograft tumor growth of LAC. Clinical analysis indicated that high level of tumor α 5-nAChR is correlated with poor survival rates of LAC patients, particularly in those expressing wild-type EGFR. Our data identified α 5-nAChR as an essential mediator for low-dose nicotine-dependent LAC progression possibly through signaling crosstalk with EGFR, supporting the involvement of environmental smoke in tumor progression in LAC patients.

In silico identification of thiostrepton as an inhibitor of cancer stem cell growth and an enhancer for chemotherapy in non-small-cell lung cancer.

Cancer stem cells (CSCs) play an important role in cancer treatment resistance and disease progression. Identifying an effective anti-CSC agent may lead to improved disease control. We used CSC-associated gene signatures to identify drug candidates that may inhibit CSC growth by reversing the CSC gene signature. Thiostrepton, a natural cyclic oligopeptide antibiotic, was the top-ranked candidate. In non-small-cell lung cancer (NSCLC) cells, thiostrepton inhibited CSC growth in vitro and reduced protein expression of cancer stemness markers, including CD133, Nanog and Oct4A. In addition, metastasis-associated Src tyrosine kinase signalling, cell migration and epithelial-to-mesenchymal transition (EMT) were all inhibited by thiostrepton. Mechanistically, thiostrepton treatment led to elevated levels of tumour suppressor miR-98. Thiostrepton combined with gemcitabine synergistically suppressed NSCLC cell growth and induced apoptosis. The inhibition of NSCLC tumours and CSC growth by thiostrepton was also demonstrated in vivo. Our findings indicate that thiostrepton, an established drug identified in silico, is an inhibitor of CSC growth and a potential enhancer of chemotherapy in NSCLC.

Pigment epithelium-derived factor peptide reverses mouse age-related meibomian gland atrophy.

Age-related meibomian gland (MG) atrophy, characterized by decreased meibocyte proliferation, is one of the causes of meibomian gland dysfunction (MGD), which leads to dry eye disease. Currently, there is no available treatment effectively preventing or reversing the decreased cell proliferation and acinar tissue atrophy. In this study, we investigated the therapeutic effects of a pigment epithelium-derived factor (PEDF) peptide in treating this condition. We found abundant expression of PEDF in the nucleus of acinar basal cells, but not in mature meibocytes, and that the expression levels were significantly decreased in the aged mice. We next treated the aged mice (15-month old) with atrophic MGs using a synthetic PEDF-derived peptide 29-mer (residues 93-121). We found that 29-mer effectively stimulated acinar basal cell proliferation and the following mature meibocyte proliferation in the atrophied MGs. In addition, the treatment increased ΔNp63 and Lrig1 expressions in acinar basal cells. Finally, the aged mice receiving the treatment showed MG growth and improved tear film break-up time. In conclusion, the 29-mer treatment is effective in promoting MG acinar basal cell proliferation and enlarging the acinar size of MG, as well as improving MG function in aged mice, suggesting a therapeutic potential of the PEDF-derived short peptide in ameliorating age-related MGD.

Pigment epithelium-derived factor peptide promotes limbal stem cell proliferation through hedgehog pathway.

Expansion of limbal epithelial stem cells (LSCs) is crucial for the success of limbal transplantation. Previous studies showed that pigment epithelium-derived peptide (PEDF) short peptide 44-mer could effectively expand LSCs and maintain them in a stem-cell state, but the mechanism remained unclear. In the current study, we found that pharmacological inhibition of Sonic Hedgehog (SHh) activity reduced the LSC holoclone number and suppressed LSC proliferation in response to 44-mer. In mice subjected to focal limbal injury, 44-mer facilitated the restoration of the LSC population in damaged limbus, and such effect was impeded by the SHh or ATGL (a PEDF receptor) inhibitor. Furthermore, we showed that 44-mer increased nuclear translocation of Gli1 and Gli3 in LSCs. Knockdown of Gli1 or Gli3 suppressed the ability of 44-mer to induce cyclin D1 expression and LSC proliferation. In addition, ATGL inhibitor suppressed the 44-mer-induced phosphorylation of STAT3 at Tyr705 in LSC. Both inhibitors for ATGL and STAT3 attenuated 44-mer-induced SHh activation and LSC proliferation. In conclusion, our data demonstrate that SHh-Gli pathway driven by ATGL/STAT3 signalling accounts for the 44-mer-mediated LSC proliferation.

OCT4B mediates hypoxia-induced cancer dissemination.

Hypoxia, the reduction of oxygen levels in cells or tissues, elicits a set of genes to adjust physiological and pathological demands during normal development and cancer progression. OCT4, a homeobox transcription factor, is essential for self-renewal of embryonic stem cells, but little is known about the role of OCT4 in non-germ-cell tumorigenesis. Here, we report that hypoxia stimulates a short isoform of OCT4, called OCT4B, via a HIF2α-dependent pathway to induce the epithelial-mesenchymal transition (EMT) and facilitate cancer dissemination. OCT4B overexpression decreased epithelial barrier properties, which led to an increase in cell migration and invasion in lung cancer cells. OCT4B knockdown attenuated HIF2α-induced EMT and inhibited cancer dissemination in cell-line and animal models. We observed that OCT4B bound the SLUG promoter and enhanced its expression, and SLUG silencing inhibited OCT4B-mediated EMT, accompanied with decreased cell migration and invasion. Correlation analysis revealed that OCT4B expression was significantly associated with the SLUG level in lung tumors. These results provide novel insights into OCT4B-mediated oncogenesis in cancer dissemination.

Upregulation of E3 Ubiquitin Ligase CBLC Enhances EGFR Dysregulation and Signaling in Lung Adenocarcinoma.

CBLC (CBL proto-oncogene c) belongs to the CBL protein family, which has E3 ubiquitin ligase activity toward activated receptor tyrosine kinases. CBLC is frequently upregulated in non-small cell lung cancer (NSCLC), yet very little is known about the functions of CBLC in tumorigenesis. Here we show that CBLC is an epigenetically demethylated target and its expression can be upregulated in NSCLC after treatment with the DNA methylation inhibitor 5'-azacytidine. Depletion of CBLC significantly inhibited cell viability and clonogenicity in vitro and reduced tumor growth in a xenograft model. CBLC silencing further sensitized EGFR-mutated NSCLC cells to treatment with tyrosine kinase inhibitors. Conversely, ectopic expression of CBLC enhanced the activation of EGFR and downstream ERK1/2 signaling after ligand stimulation by competing with CBL for EGFR binding. Analysis of ubiquitin linkages on activated EGFR (aEGFR) revealed that CBLC ubiquitinated and positively regulated aEGFR stability through the conjugation of polyubiquitin by K6 and K11 linkages. This CBLC-mediated polyubiquitination promoted either preferential recycling of aEGFR back to the plasma membrane or trafficking to the cell nucleus. IHC analyses revealed a positive correlation between phospho-EGFR and CBLC in lung adenocarcinoma. In summary, we demonstrate a novel mechanism by which aEGFR escapes lysosomal degradation in a CBLC/ubiquitin-dependent manner to sustain its activation. Our work identifies CBLC as a potential diagnostic biomarker and also points to its utilization as a novel therapeutic target for NSCLC therapy.Significance: This work demonstrates the role of CBLC expression as a diagnostic biomarker and potential therapeutic target in lung adenocarcinoma. Cancer Res; 78(17); 4984-96. ©2018 AACR.

EGFR-mediated interleukin enhancer-binding factor 3 contributes to formation and survival of cancer stem-like tumorspheres as a therapeutic target against EGFR-positive non-small cell lung cancer.

OBJECTIVES: YM155, an inhibitor of interleukin enhancer-binding factor 3 (ILF3), significantly suppresses cancer stemness property, implying that ILF3 contributes to cell survival of cancer stem cells. However, the molecular function of ILF3 inhibiting cancer stemness remains unclear. This study aimed to uncover the potential function of ILF3 involving in cell survival of epidermal growth factor receptor (EGFR)-positive lung stem-like cancer, and to investigate the potential role to improve the efficacy of anti-EGFR therapeutics. MATERIALS AND METHODS: The association of EGFR and ILF3 in expression and regulations was first investigated in this study. Lung cancer A549 cells with deprivation of ILF3 were created by the gene-knockdown method and then RNAseq was applied to identify the putative genes regulated by ILF3. Meanwhile, HCC827- and A549-derived cancer stem-like cells were used to investigate the role of ILF3 in the formation of cancer stem-like tumorspheres. RESULTS: We found that EGFR induced ILF3 expression, and YM155 reduced EGFR expression. The knockdown of ILF3 reduced not only EGFR expression in mRNA and protein levels, but also cell proliferation in vitro and in vivo, demonstrating that ILF3 may play an important role in contributing to cancer cell survival. Moreover, the knockdown and inhibition of ILF3 by shRNA and YM155, respectively, reduced the formation and survival of HCC827- and A549-derived tumorspheres through inhibiting ErbB3 (HER3) expression, and synergized the therapeutic efficacy of afatinib, a tyrosine kinase inhibitor, against EGFR-positive A549 lung cells. CONCLUSION: This study demonstrated that ILF3 plays an oncogenic like role in maintaining the EGFR-mediated cellular pathway, and can be a therapeutic target to improve the therapeutic efficacy of afatinib. Our results suggested that YM155, an ILF3 inhibitor, has the potential for utilization in cancer therapy against EGFR-positive lung cancers.

Enhanced YAP expression leads to EGFR TKI resistance in lung adenocarcinomas.

Epidermal growth factor receptor (EGFR) mutation is prevalently expressed in lung adenocarcinoma cases and acts as one of the major driving oncogenes. EGFR tyrosine kinase inhibitors (TKIs) have been used in patients with EGFR-mutant as an effective targeted therapy in lung adenocarcinoma, but drug resistance and tumor recurrence inevitably occurs. Recently, Yes-associate protein (YAP) has been reported to promote multiple cancer cell properties, such as promoting cell proliferation, epithelial-mesenchymal transition and drug resistance. This study investigated the roles of YAP in TKI-resistant lung adenocarcinoma. In TKI-sensitive cells, enhanced YAP expression leads to TKI resistant. Also, upregulated YAP expression and activation were detected in long-term TKI-induced resistant cells. With reduced YAP expression using shRNA or YAP inhibitors, TKI-resistant cells become TKI-sensitive. reduced xenograft tumor size in nude mice and Moreover, combined EGFR TKI and a YAP inhibitor, statin, prolonged survival among lung cancer patients analyzed by Taiwan National Health Insurance Research database. These observations revealed the importance of YAP in promoting TKI-resistance and combined YAP inhibition can be a potential therapy delaying the occurrence of TKI-resistance in lung adenocarcinoma.

The role of EpCAM in tumor progression and the clinical prognosis of endometrial carcinoma.

OBJECTIVE: EpCAM is a transmembrane glycoprotein that functions as an epithelial marker in endometrial tissues. However, the correlation between EpCAM and endometrial carcinoma (EC) is not clear. METHODS: This study investigated the association between EpCAM and EC. Immunohistochemistry staining and bioinformatics analysis disclosed the clinical importance of low EpCAM expression. The migratory ability of cells expressing low EpCAM levels was studied in transwell invasion assays in vitro and an orthotopic intra-uterine tumor injection model in vivo. The Connectivity MAP was used to identify drugs that effectively inhibit cells with low EpCAM expression. RESULTS: According to immunohistochemistry analysis results, low EpCAM expression was associated with an advanced stage and lymph node metastasis in patients with endometrioid EC, and high EpCAM expression favored survival. EpCAM silencing promoted cell invasion, and EpCAM re-expression in EpCAM-silenced EC cells attenuated their invasiveness. EpCAM suppression in an orthotopic uterine implantation model promoted the lymph node metastasis of EC cells. According to quantitative PCR and promoter reporter analyses, estrogen receptor alpha signaling regulated EpCAM expression by enhancing its promoter activity. As shown in the Connectivity MAP analysis, transamin inhibited the invasiveness of EpCAM-silenced EC cells. CONCLUSIONS: The loss of EpCAM may increase the malignancy of EC, and these findings provide new insights into the prognostic role of EpCAM in patients with EC.

YAP1 is essential for tumor growth and is a potential therapeutic target for EGFR-dependent lung adenocarcinomas.

Epidermal growth factor receptor (EGFR) mutations are found in lung adenocarcinomas leading to tumor cells proliferation and survival. EGFR tyrosine kinase inhibitors (TKIs) that block EGFR activity are effective therapeutics for EGFR-mutant lung adenocarcinoma patients, but TKI-resistance inevitably occurs. The YES-associated protein (YAP1) transcription coactivator has been implicated as an oncogene and is amplified in human cancers and provides tumor cells strong proliferation and survival cues. This study investigated the roles of YAP1 in lung adenocarcinoma by exploring its regulation and functions mediated by EGFR signaling. In this study, we detected a correlation between YAP1 level and EGFR mutation status in lung adenocarcinoma tissues. Using lung adenocarcinoma cell lines, enhanced YAP1 expression and activity mediated by EGFR signaling was detected through enhanced protein stability. A SRC family protein, YES, was involved in EGFR-regulated YAP1 expression and this pathway was crucial for proliferation in EGFR-dependent cells. Small molecules that reduced YAP1 levels by mechanisms bypassing EGFR signaling were effective in reducing viability in EGFR-dependent cells including those with EGFR T790M, the major cause of TKI-resistance. These observations unveiled the significance of YAP1 in EGFR mutant lung adenocarcinomas and identified YAP1 as a promising therapeutic target for EGFR-dependent lung adenocarcinoma patients, including those with EGFR T790M-caused TKI resistance.

Brain metastases in patients with non-small cell lung cancer: the role of mutated-EGFRs with an exon 19 deletion or L858R point mutation in cancer cell dissemination.

Non-small cell lung cancer (NSCLC) patients tend to develop brain metastases (BM), but the link between BM occurrence and driver mutations in NSCLC is not very clear. We explored whether activating mutations of epidermal growth factor receptors (EGFRs) in exon 19 deletion or L858R predict BM in NSCLC. A retrospective multivariable logistic regression analysis of 384 patients demonstrated that the presence of mutated-EGFRs was associated with overall BM (OR=2.24, P=0.001) compared to that of wild-type EGFR (WT-EGFR). Moreover, the time-to-event analysis model considering death as a competing risk revealed that, irrespective of survival, mutated-EGFRs predicted subsequent BM (SBM) in stage IIIB-IV patients (37.1% vs. 10.6%, HR=2.98, P=0.002) after adjusting for age (HR=2.00, P=0.012), gender, histological subtype, and smoking history. Notably, the younger mutated-EGFR subgroup was at a higher risk for SBM compared to the older WT-EGFR one (58.1% vs.10.9%, HR=6.57, P<0.001). Additionally, EGFR exon 19 deletion, despite having a slightly longer overall survival (20.6 vs. 14.2 months, P=0.368), was comparable to L858R mutation in predicting SBM (39.5% vs. 34.5%, HR=0.91, P=0.770). In vitro, the overexpression of mutated-EGFRs induced morphological changes towards a mesenchymal-like phenotype and promoted mobility in lung cancer cells. Clinically, mutated-EGFR NSCLC displayed a higher proportion of vimentin-positive expression (75.3% vs. 51.2%; P=0.007) and a shorter median time to SBM (23.5 months vs. not reached, P=0.017) than WT-EGFR NSCLC. These results suggest that NSCLC patients carrying mutated-EGFRs may require a higher frequency of brain imaging assessments than those with WT-EGFR to facilitate earlier SBM detection during follow-up.

TDP-43/HDAC6 axis promoted tumor progression and regulated nutrient deprivation-induced autophagy in glioblastoma.

Glioblastoma Multiforme (GBM) is a lethal primary brain tumor with poor survival lifespan and dismal outcome. Surgical resection of GBM is greatly limited due to the biological significance of brain, giving rise to tumor relapse in GBM patients. Transactive response DNA binding protein-43 (TDP-43) is a DNA/RNA-binding protein known for causing neurodegenerative diseases through post-translational modification; but little is known about its involvement in cancer development. In this study, we found that nutrient deprivation in GBM cell lines elevated TDP-43 expression by a mechanism of evasion from ubiquitin-dependent proteolytic pathway, and subsequently activated the autophagy process. Exogenous overexpression of TDP-43 consistently activated autophagy and suppressed stress-induced apoptosis. The inhibition of autophagy in TDP-43-overexpressing cells effectively increased the apoptotic population under nutrition shortage. Furthermore, we demonstrated that HDAC6 was involved in the activation of autophagy in TDP-43-overexpressing GBM cell lines. The treatment with SAHA, a universal HDAC inhibitor, significantly reduced TDP-43-mediated anti-apoptotic effect. Additionally, the results of immunohistochemistry showed that TDP-43 and HDAC6 collaborated in GBM-tumor lesions and negatively correlated with the relapse-free survival of GBM patients. Taken together, our results suggest that the TDP-43-HDAC6 signaling axis functions as a stress responsive pathway in GBM tumorigenesis and combats nutrient deprivation stress via activating autophagy, while inhibition of HDAC6 overpowers the pathway and provides a novel therapeutic strategy against GBM.

YM155 as an inhibitor of cancer stemness simultaneously inhibits autophosphorylation of epidermal growth factor receptor and G9a-mediated stemness in lung cancer cells.

Cancer stem cell survival is the leading factor for tumor recurrence after tumor-suppressive treatments. Therefore, specific and efficient inhibitors of cancer stemness must be discovered for reducing tumor recurrence. YM155 has been indicated to significantly reduce stemness-derived tumorsphere formation. However, the pharmaceutical mechanism of YM155 against cancer stemness is unclear. This study investigated the potential mechanism of YM155 against cancer stemness in lung cancer. Tumorspheres derived from epidermal growth factor receptor (EGFR)-mutant HCC827 and EGFR wild-type A549 cells expressing higher cancer stemness markers (CD133, Oct4, and Nanog) were used as cancer stemness models. We observed that EGFR autophosphorylation (Y1068) was higher in HCC827- and A549-derived tumorspheres than in parental cells; this autophosphorylation induced tumorsphere formation by activating G9a-mediated stemness. Notably, YM155 inhibited tumorsphere formation by blocking the autophosphorylation of EGFR and the EGFR-G9a-mediated stemness pathway. The chemical and genetic inhibition of EGFR and G9a revealed the significant role of the EGFR-G9a pathway in maintaining the cancer stemness property. In conclusion, this study not only revealed that EGFR could trigger tumorsphere formation by elevating G9a-mediated stemness but also demonstrated that YM155 could inhibit this formation by simultaneously blocking EGFR autophosphorylation and G9a activity, thus acting as a potent agent against lung cancer stemness.