Artemisia argyi extracts overcome lapatinib resistance via enhancing TMPRSS2 activation in HER2-positive breast cancer.

Breast cancer stands as the predominant malignancy and primary cause of cancer-related mortality among females globally. Approximately 25% of breast cancers exhibit HER2 overexpression, imparting a more aggressive tumor phenotype and correlating with poor prognoses. Patients with metastatic breast cancer receiving HER2 tyrosine kinase inhibitors (HER2 TKIs), such as Lapatinib, develop acquired resistance within a year, posing a critical challenge in managing this disease. Here, we explore the potential of Artemisia argyi, a Chinese herbal medicine known for its anti-cancer properties, in mitigating HER2 TKI resistance in breast cancer. Analysis of the Cancer Genome Atlas (TCGA) revealed diminished expression of transmembrane serine protease 2 (TMPRSS2), a subfamily of membrane proteolytic enzymes, in breast cancer patients, correlating with unfavorable outcomes. Intriguingly, lapatinib-responsive patients exhibited higher TMPRSS2 expression. Our study unveiled that the compounds from Artemisia argyi, eriodictyol, and umbelliferone could inhibit the growth of lapatinib-resistant HER2-positive breast cancer cells. Mechanistically, they suppressed HER2 kinase activation by enhancing TMPRSS2 activity. Our findings propose TMPRSS2 as a critical determinant in lapatinib sensitivity, and Artemisia argyi emerges as a potential agent to overcome lapatinib via activating TMPRSS2 in HER2-positive breast cancer. This study not only unravels the molecular mechanisms driving cell death in HER2-positive breast cancer cells induced by Artemisia argyi but also lays the groundwork for developing novel inhibitors to enhance therapy outcomes.

Computational fluid dynamics modeling of coronary artery blood flow using OpenFOAM: Validation with the food and drug administration benchmark nozzle model.

Cardiovascular disease (CVD), a global health concern, particularly coronary artery disease (CAD), poses a significant threat to well-being. Seeking safer and cost-effective diagnostic alternatives to invasive coronary angiography, noninvasive coronary computed tomography angiography (CCTA) gains prominence. This study employed OpenFOAM, an open-source Computational Fluid Dynamics (CFD) software, to analyze hemodynamic parameters in coronary arteries with serial stenoses. Patient-specific three-dimensional (3D) models from CCTA images offer insights into hemodynamic changes. OpenFOAM breaks away from traditional commercial software, validated against the FDA benchmark nozzle model for reliability. Applying this refined methodology to seventeen coronary arteries across nine patients, the study evaluates parameters like fractional flow reserve computed tomography simulation (FFRCTS), fluid velocity, and wall shear stress (WSS) over time. Findings include FFRCTS values exceeding 0.8 for grade 0 stenosis and falling below 0.5 for grade 5 stenosis. Central velocity remains nearly constant for grade 1 stenosis but increases 3.4-fold for grade 5 stenosis. This research innovates by utilizing OpenFOAM, departing from previous reliance on commercial software. Combining qualitative stenosis grading with quantitative FFRCTS and velocity measurements offers a more comprehensive assessment of coronary artery conditions. The study introduces 3D renderings of wall shear stress distribution across stenosis grades, providing an intuitive visualization of hemodynamic changes for valuable insights into coronary stenosis diagnosis.

l-lactic acidosis confers insensitivity to PKC inhibitors by competing for uptake via monocarboxylate transporters.

Targeting protein kinase C (PKC) family was found to repress the migration and resistance of non-small cell lung cancer cells to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). However, none of the PKC inhibitors has been approved for anticancer therapy yet due to the limited efficacy in clinical trials, and the underlying mechanisms remain unclear. l-lactic acidosis, a common condition comprising high l-lactate concentration and acidic pH in the tumor microenvironment, has been known to induce tumor metastasis and drug resistance. In this study, l-lactic acid was found to reverse the inhibitory effects of pan-PKC inhibitors GO6983 on PKC activity, cell migration, and EGFR-TKI resistance, but these effects were not affected by the modulators of lactate receptor GPR81. Interestingly, blockade of lactate transporters, monocarboxylate transporter-1 and -4 (MCT1 and MCT4), attenuated the intracellular level of GO6983, and its inhibitory effect on PKC activity, suggesting that lactic acid promotes the resistance to PKC inhibitors by competing for the uptake through these transporters rather than by activating its receptor, GPR81. Our findings explain the underlying mechanisms of the limited response of PKC inhibitors in clinical trials.

A Structural Comparison of SARS-CoV-2 Main Protease and Animal Coronaviral Main Protease Reveals Species-Specific Ligand Binding and Dimerization Mechanism.

Animal coronaviruses (CoVs) have been identified to be the origin of Severe Acute Respiratory Syndrome (SARS)-CoV, Middle East respiratory syndrome (MERS)-CoV, and probably SARS-CoV-2 that cause severe to fatal diseases in humans. Variations of zoonotic coronaviruses pose potential threats to global human beings. To overcome this problem, we focused on the main protease (Mpro), which is an evolutionary conserved viral protein among different coronaviruses. The broad-spectrum anti-coronaviral drug, GC376, was repurposed to target canine coronavirus (CCoV), which causes gastrointestinal infections in dogs. We found that GC376 can efficiently block the protease activity of CCoV Mpro and can thermodynamically stabilize its folding. The structure of CCoV Mpro in complex with GC376 was subsequently determined at 2.75 Å. GC376 reacts with the catalytic residue C144 of CCoV Mpro and forms an (R)- or (S)-configuration of hemithioacetal. A structural comparison of CCoV Mpro and other animal CoV Mpros with SARS-CoV-2 Mpro revealed three important structural determinants in a substrate-binding pocket that dictate entry and release of substrates. As compared with the conserved A141 of the S1 site and P188 of the S4 site in animal coronaviral Mpros, SARS-CoV-2 Mpro contains N142 and Q189 at equivalent positions which are considered to be more catalytically compatible. Furthermore, the conserved loop with residues 46-49 in animal coronaviral Mpros has been replaced by a stable α-helix in SARS-CoV-2 Mpro. In addition, the species-specific dimerization interface also influences the catalytic efficiency of CoV Mpros. Conclusively, the structural information of this study provides mechanistic insights into the ligand binding and dimerization of CoV Mpros among different species.

miR-221 confers lapatinib resistance by negatively regulating p27kip1 in HER2-positive breast cancer.

Development of acquired resistance to lapatinib, a dual epidermal growth factor receptor (EGFR)/human epidermal growth factor receptor 2 (HER2) tyrosine kinase inhibitor, severely limits the duration of clinical response in advanced HER2-driven breast cancer patients. Although the compensatory activation of the PI3K/Akt survival signal has been proposed to cause acquired lapatinib resistance, comprehensive molecular mechanisms remain required to develop more efficient strategies to circumvent this therapeutic difficulty. In this study, we found that suppression of HER2 by lapatinib still led to Akt inactivation and elevation of FOX3a protein levels, but failed to induce the expression of their downstream pro-apoptotic effector p27kip1 , a cyclin-dependent kinase inhibitor. Elevation of miR-221 was found to contribute to the development of acquired lapatinib resistance by targeting p27kip1 expression. Furthermore, upregulation of miR-221 was mediated by the lapatinib-induced Src family tyrosine kinase and subsequent NF-κB activation. The reversal of miR-221 upregulation and p27kip1 downregulation by a Src inhibitor, dasatinib, can overcome lapatinib resistance. Our study not only identified miRNA-221 as a pivotal factor conferring the acquired resistance of HER2-positive breast cancer cells to lapatinib through negatively regulating p27kip1 expression, but also suggested Src inhibition as a potential strategy to overcome lapatinib resistance.

Crystal structure of the N-terminal domain of TagH reveals a potential drug targeting site.

Bacterial wall teichoic acids (WTAs) are synthesized intracellularly and exported by a two-component transporter, TagGH, comprising the transmembrane and ATPase subunits TagG and TagH. Here the dimeric structure of the N-terminal domain of TagH (TagH-N) was solved by single-wavelength anomalous diffraction using a selenomethionine-containing crystal, which shows an ATP-binding cassette (ABC) architecture with RecA-like and helical subdomains. Besides significant structural differences from other ABC transporters, a prominent patch of positively charged surface is seen in the center of the TagH-N dimer, suggesting a potential binding site for the glycerol phosphate chain of WTA. The ATPase activity of TagH-N was inhibited by clodronate, a bisphosphonate, in a non-competitive manner, consistent with the proposed WTA-binding site for drug targeting.

P300 Acetyltransferase Mediates Stiffness-Induced Activation of Hepatic Stellate Cells Into Tumor-Promoting Myofibroblasts.

BACKGROUND & AIMS: Hepatic stellate cells (HSCs) contribute to desmoplasia and stiffness of liver metastases by differentiating into matrix-producing myofibroblasts. We investigated whether stiffness due to the presence of tumors increases activation of HSCs into myofibroblasts and their tumor-promoting effects, as well as the role of E1A binding protein p300, a histone acetyltransferase that regulates transcription, in these processes. METHODS: HSCs were isolated from liver tissues of patients, mice in which the p300 gene was flanked by 2 loxP sites (p300F/F mice), and p300+/+ mice (controls). The HSCs were placed on polyacrylamide gels with precisely defined stiffness, and their activation (differentiation into myofibroblasts) was assessed by immunofluorescence and immunoblot analyses for alpha-smooth muscle actin. In HSCs from mice, the p300 gene was disrupted by cre recombinase. In human HSCs, levels of p300 were knocked down with small hairpin RNAs or a mutant form of p300 that is not phosphorylated by AKT (p300S1834A) was overexpressed. Human HSCs were also cultured with inhibitors of p300 (C646), PI3K signaling to AKT (LY294002), or RHOA (C3 transferase) and effects on stiffness-induced activation were measured. RNA sequencing and chromatin immunoprecipitation-quantitative polymerase chain reaction were used to identify HSC genes that changed expression levels in response to stiffness. We measured effects of HSC-conditioned media on proliferation of HT29 colon cancer cells and growth of tumors following subcutaneous injection of these cells into mice. MC38 colon cancer cells were injected into portal veins of p300F/Fcre and control mice, and liver metastases were measured. p300F/Fcre and control mice were given intraperitoneal injections of CCl4 to induce liver fibrosis. Liver tissues were collected and analyzed by immunofluorescence, immunoblot, and histology. RESULTS: Substrate stiffness was sufficient to activate HSCs, leading to nuclear accumulation of p300. Disrupting p300 level or activity blocked stiffness-induced activation of HSCs. In HSCs, substrate stiffness activated AKT signaling via RHOA to induce phosphorylation of p300 at serine 1834; this caused p300 to translocate to the nucleus, where it up-regulated transcription of genes that increase activation of HSCs and metastasis, including CXCL12. MC38 cells, injected into portal veins, formed fewer metastases in livers of p300F/Fcre mice than control mice. Expression of p300 was increased in livers of mice following injection of CCl4; HSC activation and collagen deposition were reduced in livers of p300F/Fcre mice compared with control mice. CONCLUSIONS: In studies of mice, we found liver stiffness to activate HSC differentiation into myofibroblasts, which required nuclear accumulation of p300. p300 increases HSC expression of genes that promote metastasis.

Melatonin reduces lung cancer stemness through inhibiting of PLC, ERK, p38, ß-catenin, and Twist pathways.

Lung cancer is one of the most common cancer in cancer-related deaths worldwide, which is characterized by its strong metastatic potential. The melatonin hormone secreted by the pineal grand has an antioxidant effect and protects cells against carcinogenic substances. However, the effects of melatonin in lung cancer stemness are largely unknown. We found that melatonin reduces CD133 expression by ~50% in lung cancer cell lines, while results of a sphere formation assay showed that melatonin inhibits lung cancer stemness. These effects of melatonin were reversed when the cell lines were incubated with phospholipase C (PLC), ERK/p38, and a ß-catenin activator. Transfection with Twist siRNA augmented the inhibitory effects of melatonin, indicating that melatonin suppresses lung cancer stemness by inhibiting the PLC, ERK/p38, ß-catenin, and Twist signaling pathways. We also found CD133 expression is positively correlated with Twist expression in lung cancer specimens. Melatonin shows promise in the treatment of lung cancer stemness and deserves further study.

Proteasome Inhibitors Suppress ErbB Family Expression through HSP90-Mediated Lysosomal Degradation.

Although dual EGFR/HER2 tyrosine kinase inhibitor lapatinib has provided effective clinical benefits for HER2-positive breast cancer patients, acquired resistance to this drug remains a major concern. Thus, the development of alternative therapeutic strategies is urgently needed for patients who failed lapatinib treatment. Proteasome inhibitors have been reported to possess high anti-tumor activity to breast cancer cells. Therefore, this study aims to examine whether and how proteasome inhibitor bortezomib can overcome lapatinib resistance. Treatments with several proteasome inhibitors, including Bortezomib, MG132, and proteasome inhibitor I (PSI), as well as the viabilities of both HER2-positive breast cancer cell lines and their lapatinib-resistant clones, were inhibited. Importantly, the expressions of ErbB family were downregulated at both transcriptional and translational levels. Also, our results further indicated that proteasome inhibitors decreased ErbB family expression through lysosomal degradation pathway in a heat shock protein 90 (HSP90)-dependent manner. In this study, our data supported a potential approach to overcome the acquired resistance of HER2-overexpressing breast cancer patients to lapatinib using proteasome inhibitors.

Auramine O, an incense smoke ingredient, promotes lung cancer malignancy.

Burning incense to worship deities is a popular religious ritual in large parts of Asia, and is a popular custom affecting more than 1.5 billion adherents. Due to incomplete combustion, burning incense has been well recognized to generate airborne hazards to human health. However, the correlation between burning incense and lung cancer in epidemiological studies remains controversy. Therefore, we speculated that some unknown materials in incense smoke are involved in the initiation or progression of lung cancer. Based on this hypothesis, we identified a major compound auramine O (AuO) from the water-soluble fraction of incense burned condensate using mass spectrometry. AuO is commonly used in incense manufacture as a colorant. Due to thermostable, AuO released from burned incenses becomes an unexpected air pollutant. AuO is classified as a Group 2B chemical by the International Agency of Research on Cancer (IARC), however, the damage of AuO to the respiratory system remains elusive. Our study revealed that AuO has no apparent effect on malignant transformation; but, it dramatically promotes lung cancer malignancy. AuO accumulates in the nucleus and induces the autophagy activity in lung tumor cells. AuO significantly enhances migration and invasive abilities and the in vitro and in vivo stemness features of lung tumor cells through activating the expression of aldehyde dehydrogenase family 1 member A1 (ALDH1A1), and ALDH1A1 knockdown attenuates AuO-induced autophagy activity and blocks AuO-induced lung tumor malignancy. In conclusion, we found that AuO, an ingredient of incense smoke, significantly increases the metastatic abilities and stemness characters of lung tumor cells through the activation of ALDH1A1, which is known to be associated with poor outcome and progression of lung cancer. For public health, reducing or avoiding the use of AuO in incense is recommended.

Downregulation of microRNA-15b by hepatitis B virus X enhances hepatocellular carcinoma proliferation via fucosyltransferase 2-induced Globo H expression.

Globo H, a cancer-associated carbohydrate antigen, is highly expressed in various types of cancers. However, the role of Globo H in hepatocellular carcinoma (HCC) remains elusive. In our study, we performed glycan microarray analysis of 134 human serum samples to explore anti-Globo H antibody changes and found that Globo H is upregulated in hepatitis B virus (HBV)-positive HCC. Similarly, immunohistochemistry showed that Globo H expression was higher in tumors compared to normal tissues. In addition, fucosyltransferase 2 (FUT2), the main synthetic enzyme of Globo H, was also increased in HCC cells overexpressing HBV X protein (HBX). HBX plays an important role in promoting cell proliferation and may be related to increased levels of FUT2 and Globo H. Furthermore, using microRNA profiling, we observed that microRNA-15b (miR-15b) was downregulated in patients with HCC and confirmed association of FUT2 expression with expression of its product, Globo H. Therefore, our results suggest that HBX suppressed the expression of miR-15b, which directly targeted FUT2 and then increased levels of Globo H to enhance HCC cell proliferation. Additionally, proliferation of HBX-overexpressing HCC cells was significantly inhibited by treatment with Globo H antibody in vitro. In xenograft animal experiments, we found that overexpression of miR-15b effectively suppressed tumor growth. The newly identified HBX/miR-15b/FUT2/Globo H axis suggests one possible molecular mechanism of HCC cell proliferation and represents a new potential therapeutic target for HCC treatment.

MicroRNA-657 promotes tumorigenesis in hepatocellular carcinoma by targeting transducin-like enhancer protein 1 through nuclear factor kappa B pathways.

UNLABELLED: Growing evidence indicates that deregulation of microRNAs (miRNAs) contributes to tumorigenesis. Dysregulation of miR-657 has been observed in several types of cancers, but its biological function is still largely unknown. Our results showed that miR-657 expression can be induced by hepatitis viral proteins and is significantly increased in hepatocellular carcinoma (HCC) tissues. Moreover, introduction of miR-657 dramatically increases proliferation and colony formation of HCC cells in vitro and induces tumor development in immunodeficient mice. Further studies showed that miR-657 directly targets the transducin-like enhancer protein 1 (TLE1) 3' untranslated region (UTR) and activates nuclear factor kappa B (NF-κB) pathways that contribute to hepatocarcinogenesis. CONCLUSION: This study identified a mechanism whereby miRNA-657 contributed to HCC through novel cancer pathways and provides new insights into the potential molecular mechanisms of hepatic carcinogenesis.

Validation of the Chinese Version of Penn Alcohol Craving Scale for Patients With Alcohol Use Disorder.

OBJECTIVE: The Penn Alcohol Craving Scale (PACS) is a five-item, single-dimension questionnaire that is used to measure a patient's alcohol craving. We sought to develop the Chinese version of the PACS (PACS-C) and assess its reliability and validity. METHODS: A total of 160 Taiwanese patients with alcohol use disorder were enrolled in this study. The internal consistency and concurrent validity of the PASC-C with the visual analogue scale (VAS) for craving, the Yale-Brown Obsessive Compulsive Scale for heavy drinking (YBOCS-hd), and the Severity of Alcohol Dependence Questionnaire (SADQ) were assessed. The test-retest reliability of the PASC-C was evaluated 1 day after the baseline measurements. Confirmatory factor analysis (CFA) was performed to examine the psychometric properties of the PACS-C. RESULTS: The PACS-C exhibited good internal consistency (Cronbach's α=0.95) and test-retest reliability (r=0.97). This scale showed high correlations with the VAS (r=0.81) and YBOCS-hd (r=0.81 and 0.79 for the obsession and compulsion subscales, respectively), and moderate correlation with the SADQ-C (r=0.47). Furthermore, CFA results revealed that the PACS-C had good fit indices under various models. CONCLUSION: The PACS-C appears to be a reliable and valid tool for assessing alcohol craving in patients with alcohol use disorder in Taiwan.

Cigarette smoke promotes IL-6-dependent lung cancer migration and osteolytic bone metastasis.

Lung cancer stands as a major contributor to cancer-related fatalities globally, with cigarette smoke playing a pivotal role in its development and metastasis. Cigarette smoke is also recognized as a risk factor for bone loss disorders like osteoporosis. However, the association between cigarette smoke and another bone loss disorder, lung cancer osteolytic bone metastasis, remains largely uncertain. Our Gene Set Enrichment Analysis (GSEA) indicated that smokers among lung cancer patients exhibited higher expression levels of bone turnover gene sets. Both The Cancer Genome Atlas (TCGA) database and our clinic samples demonstrated elevated expression of the osteolytic factor IL-6 in ever-smokers with bone metastasis among lung cancer patients. Our cellular experiments revealed that benzo[α]pyrene (B[α]P) and cigarette smoke extract (CSE) promoted IL-6 production and cell migration in lung cancer. Activation of the PI3K, Akt, and NF-κB signaling pathways was involved in cigarette smoke-augmented IL-6-dependent migration. Additionally, cigarette smoke lung cancer-secreted IL-6 promoted osteoclast formation. Importantly, blocking IL-6 abolished cigarette smoke-facilitated lung cancer osteolytic bone metastasis in vivo. Our findings provide evidence that cigarette smoke is a risk factor for osteolytic bone metastasis. Thus, inhibiting IL-6 may be a valuable therapeutic strategy for managing osteolytic bone metastasis in lung cancer patients who smoke.

Particulate matter facilitates amphiregulin-dependent lung cancer proliferation through glutamine metabolism.

Although many cohort studies have reported that long-term exposure to particulate matter (PM) causes lung cancer, the molecular mechanisms underlying the PM-induced increases in lung cancer progression remain unclear. We applied the lung cancer cell line A549 (Parental; A549.Par) to PM for an extended period to establish a mimic PM-exposed lung cancer cell line, A549.PM. Our results indicate that A549.PM exhibits higher cell growth and proliferation abilities compared to A549.Par cells in vitro and in vivo. The RNA sequencing analysis found amphiregulin (AREG) plays a critical role in PM-induced cell proliferation. We observed that PM increases AREG-dependent lung cancer proliferation through glutamine metabolism. In addition, the EGFR/PI3K/AKT/mTOR signaling pathway is involved in PM-induced solute carrier family A1 member 5 (SLC1A5) expression and glutamine metabolism. Our findings offer important insights into how lung cancer proliferation develops upon exposure to PM.

Lapatinib-mediated cyclooxygenase-2 expression via epidermal growth factor receptor/HuR interaction enhances the aggressiveness of triple-negative breast cancer cells.

Lapatinib, a dual epidermal growth factor receptor (EGFR)/human epidermal growth factor receptor 2 (HER2) kinase inhibitor, showed clinical benefits in advanced HER2-positive breast cancer patients. Because some triple-negative breast cancers (TNBCs) frequently overexpress EGFR, the antitumor activity of lapatinib in such diseases was also tested. However, the results showed a worse event-free survival rate. It remains unknown whether and how lapatinib elicits the aggressiveness of such cancer cells. In this study, our results demonstrated that lapatinib facilitated axillary and lung metastases of triple-negative MDA-MB-231 breast cancer cells without affecting their viability, leading to worse survival in orthotopic xenograft mice. The lapatinib-increased motility was attributed by the elevation of EGFR through the downregulation of microRNA-7 and by the subsequent overexpression of cyclooxygenase-2 (COX-2). Strikingly, independent of its kinase activity, the elevated EGFR at least partly stabilized COX-2 expression by enhancing the binding of HuR to COX-2 mRNA. Our results suggest that lapatinib may increase the migration and invasion of MDA-MB-231 cells by upregulating EGFR and COX-2 through the downregulation of microRNA-7, providing a potential explanation for the worse clinical outcome of TNBC patients who receive lapatinib-based treatment. These findings also shed new light on the molecular mechanism of COX-2 mRNA stabilization by EGFR in a kinase-independent manner.

Lapatinib-induced NF-kappaB activation sensitizes triple-negative breast cancer cells to proteasome inhibitors.

INTRODUCTION: Triple-negative breast cancer (TNBC), a subtype of breast cancer with negative expressions of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2), is frequently diagnosed in younger women and has poor prognosis for disease-free and overall survival. Due to the lack of known oncogenic drivers for TNBC proliferation, clinical benefit from currently available targeted therapies is limited, and new therapeutic strategies are urgently needed. METHODS: Triple-negative breast cancer cell lines were treated with proteasome inhibitors in combination with lapatinib (a dual epidermal growth factor receptor (EGFR)/HER2 tyrosine kinase inhibitor). Their in vitro and in vivo viability was examined by MTT assay, clonogenic analysis, and orthotopic xenograft mice model. Luciferase reporter gene, immunoblot, and RT-qPCR, immunoprecipitation assays were used to investigate the molecular mechanisms of action. RESULTS: Our data showed that nuclear factor (NF)-κB activation was elicited by lapatinib, independent of EGFR/HER2 inhibition, in TNBCs. Lapatinib-induced constitutive activation of NF-κB involved Src family kinase (SFK)-dependent p65 and IκBα phosphorylations, and rendered these cells more vulnerable to NF-κB inhibition by p65 small hairpin RNA. Lapatinib but not other EGFR inhibitors synergized the anti-tumor activity of proteasome inhibitors both in vitro and in vivo. Our results suggest that treatment of TNBCs with lapatinib may enhance their oncogene addiction to NF-κB, and thus augment the anti-tumor activity of proteasome inhibitors. CONCLUSIONS: These findings suggest that combination therapy of a proteasome inhibitor with lapatinib may benefit TNBC patients.

EGFR-SGLT1 interaction does not respond to EGFR modulators, but inhibition of SGLT1 sensitizes prostate cancer cells to EGFR tyrosine kinase inhibitors.

BACKGROUND: Overexpression of epidermal growth factor receptor (EGFR) is associated with poor prognosis in malignant tumors. Sodium/glucose co-transporter 1 (SGLT1) is an active glucose transporter that is overexpressed in many cancers including prostate cancer. Previously, we found that EGFR interacts with and stabilizes SGLT1 in cancer cells. METHODS: In this study, we determined the micro-domain of EGFR that is required for its interaction with SGLT1 and the effects of activation/inactivation of EGFR on EGFR-SGLT1 interaction, measured the expression of EGFR and SGLT1 in prostate cancer tissues, and tested the effect of inhibition of SGLT1 on the sensitivity of prostate cancer cells to EGFR tyrosine inhibitors. RESULTS: We found that the autophosphorylation region (978-1210 amino acids) of EGFR was required for its sufficient interaction with SGLT1 and that this interaction was independent of EGFR's tyrosine kinase activity. Most importantly, the EGFR-SGLT1 interaction does not respond to EGFR tyrosine kinase modulators (EGF and tyrosine kinase inhibitors). EGFR and SGLT1 co-localized in prostate cancer tissues, and inhibition of SGLT1 by a SGLT1 inhibitor (Phlorizin) sensitized prostate cancer cells to EGFR inhibitors (Gefitinib and Erlotinib). CONCLUSION: These data suggest that EGFR in cancer cells can exist as either a tyrosine kinase modulator responsive status or an irresponsive status. SGLT1 is a protein involved in EGFR's functions that are irresponsive to EGFR tyrosine kinase inhibitors and, therefore, the EGFR-SGLT1 interaction might be a novel target for prostate cancer therapy.

Beyond NF-κB activation: nuclear functions of IκB kinase α.

IκB kinase (IKK) complex, the master kinase for NF-κB activation, contains two kinase subunits, IKKα and IKKß. In addition to mediating NF-κB signaling by phosphorylating IκB proteins during inflammatory and immune responses, the activation of the IKK complex also responds to various stimuli to regulate diverse functions independently of NF-κB. Although these two kinases share structural and biochemical similarities, different sub-cellular localization and phosphorylation targets between IKKα and IKKß account for their distinct physiological and pathological roles. While IKKß is predominantly cytoplasmic, IKKα has been found to shuttle between the cytoplasm and the nucleus. The nuclear-specific roles of IKKα have brought increasing complexity to its biological function. This review highlights major advances in the studies of the nuclear functions of IKKα and the mechanisms of IKKα nuclear translocation. Understanding the nuclear activity is essential for targeting IKKα for therapeutics.

Quantitative flow measurement by digital subtraction angiography in cerebral carotid stenosis using optical flow method.

OBJECTIVE: We analyzed intracranial regional blood flows using an optical flow method (OFM) and digital subtraction angiography in patients with internal carotid artery (ICA) stenosis. We also retrospectively explored the correlation between the patients' diagnoses and the severity of the ICA stenoses. MATERIALS AND METHODS: OFM, an image-processing algorithm to estimate motion, was applied to determine the mean velocity V(mean) in the vessels. A group of 40 patients without vascular anomalies acted as the control group. The patients were classified as having either moderate stenosis (< 80%, n=14) or severe stenosis (> 80%, n=23). RESULTS: The V(mean) of the ICAs was significantly lower in the stenotic group compared with the control group (p< 0.01). The V(mean) of the ICAs was inversely correlated with the severity of the stenosis (p< 0.05). The receiver operating characteristic curve of the V(mean) in an AP view showed substantial discriminatory power, with an optimal cutoff value of 3.48 pixels/frame for the detection of patients with carotid stenosis. The sensitivity and specificity were 84% and 50%, respectively. On a lateral view, the best cutoff for the V(mean) was 4.01 pixels/frame, and the sensitivity and specificity were 92% and 43%, respectively. CONCLUSIONS: Digital subtraction angiography combined with the OFM is a feasible parametric method for intracranial blood flow measurements in patients with moderate to severe carotid stenosis.