TP53 Induced Glycolysis and Apoptosis Regulator and Monocarboxylate Transporter 4 drive metabolic reprogramming with c-MYC and NFkB activation in breast cancer.

Breast cancer is composed of metabolically coupled cellular compartments with upregulation of TP53 Induced Glycolysis and Apoptosis Regulator (TIGAR) in carcinoma cells and loss of caveolin 1 (CAV1) with upregulation of monocarboxylate transporter 4 (MCT4) in fibroblasts. The mechanisms that drive metabolic coupling are poorly characterized. The effects of TIGAR on fibroblast CAV1 and MCT4 expression and breast cancer aggressiveness was studied using coculture and conditioned media systems and in-vivo. Also, the role of cytokines in promoting tumor metabolic coupling via MCT4 on cancer aggressiveness was studied. TIGAR downregulation in breast carcinoma cells reduces tumor growth. TIGAR overexpression in carcinoma cells drives MCT4 expression and NFkB activation in fibroblasts. IL6 and TGFB drive TIGAR upregulation in carcinoma cells, reduce CAV1 and increase MCT4 expression in fibroblasts. Tumor growth is abrogated in the presence of MCT4 knockout fibroblasts and environment. We discovered coregulation of c-MYC and TIGAR in carcinoma cells driven by lactate. Metabolic coupling primes the tumor microenvironment allowing for production, uptake and utilization of lactate. In sum, aggressive breast cancer is dependent on metabolic coupling.

Increased expression of desmin and vimentin reduces bladder smooth muscle contractility via JNK2.

Bladder dysfunction is associated with the overexpression of the intermediate filament (IF) proteins desmin and vimentin in obstructed bladder smooth muscle (BSM). However, the mechanisms by which these proteins contribute to BSM dysfunction are not known. Previous studies have shown that desmin and vimentin directly participate in signal transduction. In this study, we hypothesized that BSM dysfunction associated with overexpression of desmin or vimentin is mediated via c-Jun N-terminal kinase (JNK). We employed a model of murine BSM tissue in which increased expression of desmin or vimentin was induced by adenoviral transduction to examine the sufficiency of increased IF protein expression to reduce BSM contraction. Murine BSM strips overexpressing desmin or vimentin generated less force in response to KCl and carbachol relative to the levels in control murine BSM strips, an effect associated with increased JNK2 phosphorylation and reduced myosin light chain (MLC20 ) phosphorylation. Furthermore, desmin and vimentin overexpressions did not alter BSM contractility and MLC20 phosphorylation in strips isolated from JNK2 knockout mice. Pharmacological JNK2 inhibition produced results qualitatively similar to those caused by JNK2 knockout. These findings suggest that inhibition of JNK2 may improve diminished BSM contractility associated with obstructive bladder disease.

NF-κB and GATA-Binding Factor 6 Repress Transcription of Caveolins in Bladder Smooth Muscle Hypertrophy.

Caveolins (CAVs) are structural proteins of caveolae that function as signaling platforms to regulate smooth muscle contraction. Loss of CAV protein expression is associated with impaired contraction in obstruction-induced bladder smooth muscle (BSM) hypertrophy. In this study, microarray analysis of bladder RNA revealed down-regulation of CAV1, CAV2, and CAV3 gene transcription in BSM from models of obstructive bladder disease in mice and humans. We identified and characterized regulatory regions responsible for CAV1, CAV2, and CAV3 gene expression in mice with obstruction-induced BSM hypertrophy, and in men with benign prostatic hyperplasia. DNA affinity chromatography and chromatin immunoprecipitation assays revealed a greater increase in binding of GATA-binding factor 6 (GATA-6) and NF-κB to their cognate binding motifs on CAV1, CAV2, and CAV3 promoters in obstructed BSM relative to that observed in control BSM. Knockout of NF-κB subunits, shRNA-mediated knockdown of GATA-6, or pharmacologic inhibition of GATA-6 and NF-κB in BSM increased CAV1, CAV2, and CAV3 transcription and promoter activity. Conversely, overexpression of GATA-6 decreased CAV2 and CAV3 transcription and promoter activity. Collectively, these data provide new insight into the mechanisms by which CAV gene expression is repressed in hypertrophied BSM in obstructive bladder disease.

TP53-inducible Glycolysis and Apoptosis Regulator (TIGAR) Metabolically Reprograms Carcinoma and Stromal Cells in Breast Cancer.

A subgroup of breast cancers has several metabolic compartments. The mechanisms by which metabolic compartmentalization develop in tumors are poorly characterized. TP53 inducible glycolysis and apoptosis regulator (TIGAR) is a bisphosphatase that reduces glycolysis and is highly expressed in carcinoma cells in the majority of human breast cancers. Hence we set out to determine the effects of TIGAR expression on breast carcinoma and fibroblast glycolytic phenotype and tumor growth. The overexpression of this bisphosphatase in carcinoma cells induces expression of enzymes and transporters involved in the catabolism of lactate and glutamine. Carcinoma cells overexpressing TIGAR have higher oxygen consumption rates and ATP levels when exposed to glutamine, lactate, or the combination of glutamine and lactate. Coculture of TIGAR overexpressing carcinoma cells and fibroblasts compared with control cocultures induce more pronounced glycolytic differences between carcinoma and fibroblast cells. Carcinoma cells overexpressing TIGAR have reduced glucose uptake and lactate production. Conversely, fibroblasts in coculture with TIGAR overexpressing carcinoma cells induce HIF (hypoxia-inducible factor) activation with increased glucose uptake, increased 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 (PFKFB3), and lactate dehydrogenase-A expression. We also studied the effect of this enzyme on tumor growth. TIGAR overexpression in carcinoma cells increases tumor growth in vivo with increased proliferation rates. However, a catalytically inactive variant of TIGAR did not induce tumor growth. Therefore, TIGAR expression in breast carcinoma cells promotes metabolic compartmentalization and tumor growth with a mitochondrial metabolic phenotype with lactate and glutamine catabolism. Targeting TIGAR warrants consideration as a potential therapy for breast cancer.

Predictors of positive surgical margins after radical prostatectomy at a single institution: preoperative and pathologic factors, and the impact of surgeon variability and technique on incidence and location.

INTRODUCTION: To identify and assess predictive factors for positive surgical margins (PSM) in patients undergoing radical prostatectomy (RP). MATERIALS AND METHODS: An Institution Review Board (IRB) approved retrospective review of 1751 patients that underwent RP from March 2000 to June 2013 was performed. Identified were 1740 patients whom had not received neoadjuvant therapy; these were used for the purpose of this analysis. Univariate and multivariate analysis were performed to determine factors associated with and predictive of PSMs, divided into preoperative and pathological. Variables analyzed include age, body mass index (BMI), race, surgeon, surgical modality, pathologic T-stage and Gleason sum, extracapsular extension (ECE), seminal vesicle involvement (SVI), perineural invasion (PNI) and prostate weight. Finally, each surgical technique was analyzed to determine the most common site of PSM. RESULTS: Rate of PSM was 23.6%. Our analysis showed that preoperative prostate-specific antigen (PSA) level ≥ 10ng/mL, and pathologic T3/T4-stage and PNI significantly predicted PSM. Age > 60 years and prostate weight > 60 g were predictive against PSM. Gleason score ≥ 7 and PSM were significant risk factors for biochemical recurrence (BCR). Surgical approach did not affect the rate of PSM. Open RP was associated with a higher apical PSM rate (38.5%) and robotic RP with a higher posterolateral PSM rate (52.3%). CONCLUSIONS: High preoperative PSA levels, and advanced TNM-staging predicted positive surgical margins in our cohort. Patients with PSM were subsequently found to have higher risk of BCR.

The potential value of phosphohistone-h3 mitotic index determined by digital image analysis in the assessment of pancreatic endocrine tumors in fine-needle aspiration cytology specimens.

OBJECTIVE: According to the World Health Organization, pancreatic endocrine tumors are graded by assessment of the Ki67 proliferation index and/or mitotic count. The objective was to find comparable grading on the basis of the novel mitotic marker phosphohistone-H3 (PHH3). STUDY DESIGN: A computer-assisted system was used to assess 23 cell blocks stained with PHH3 and Ki67 antibodies. We investigated possible cut-points for PHH3 and computed percent agreement between the PHH3- and Ki67-based grading. RESULTS: The Spearman correlation between percent Ki67 positive and percent PHH3 positive was 0.76 (p = 0.001). A value of 0.3% for the lower cut-point ('cut-point 1', differentiating between grades 1 and 2) and values of about 1.8-1.9% for the higher cut-point ('cut-point 2', differentiating between grades 2 and 3) shows optimal agreement between PHH3 and Ki67 grading. The percentage of positive cells was much higher for Ki67 than for PHH3 (mean 10.6 vs. 3.0%). CONCLUSIONS: PHH3 has good correlation with Ki67, but the range of PHH3 positivity is much narrower than that of Ki67 (range 0-4% for PHH3 vs. 0-50% for Ki67). Therefore, to be as accurate, grading on the basis of PHH3 requires evaluation of a larger number of tumor cells for a precise determination of percent PHH3-positive nuclei.

Does mitosis-specific marker phosphohistone H3 help the grading of upper tract urothelial carcinomas in cell blocks?

BACKGROUND: Grading upper tract urothelial carcinomas (UTUC) in cell blocks with small distorted tissue fragments can be challenging; interobserver agreement is poor among pathologists. Mitotic figure (MF) counting along with nuclear features is important in grading these tumors. We evaluated the use of the mitotic-specific marker phosphohistone H3 (PHH3) as an adjunct to hematoxylin and eosin (H&E) stain for grading UTUC in cell blocks. METHODS: Formalin-fixed, paraffin-embedded tissues from the cell blocks of 61 UTUC were stained with H&E and PHH3 antibody. The grading of tumors was performed independently by 3 pathologists, on both H&E-stained and PHH3 plus H&E-stained slides. The grading system used was the 1973 WHO 3-point grading system. Gradings were compared by all the pathologists for H&E staining versus PHH3 plus H&E staining with the Stuart-Maxwell test of marginal homogeneity that accounts for the matched data. RESULTS: The average pairwise agreement by H&E alone was 55%, and 80% by PHH3 plus H&E. CONCLUSION: By adding PHH3 immunostain to the H&E, the agreement in grading the carcinomas among the 3 pathologists improved dramatically. PHH3 immunostain may play an important role in grading UTUC in small cell block samples.

Bone Health Management in the Continuum of Prostate Cancer Disease.

Prostate cancer (PCa) is the second-leading cause of cancer-related deaths in men. PCa cells require androgen receptor (AR) signaling for their growth and survival. Androgen deprivation therapy (ADT) is the preferred treatment for patients with locally advanced and metastatic PCa disease. Despite their initial response to androgen blockade, most patients eventually will develop metastatic castration-resistant prostate cancer (mCRPC). Bone metastases are common in men with mCRPC, occurring in 30% of patients within 2 years of castration resistance and in >90% of patients over the course of the disease. Patients with mCRPC-induced bone metastasis develop lesions throughout their skeleton; the 5-year survival rate for these patients is 47%. Bone-metastasis-induced early changes in the bone that proceed the osteoblastic response in the bone matrix are monitored and detected via modern magnetic resonance and PET/CT imaging technologies. Various treatment options, such as targeting osteolytic metastasis with bisphosphonates, prednisone, dexamethasone, denosumab, immunotherapy, external beam radiation therapy, radiopharmaceuticals, surgery, and pain medications are employed to treat prostate-cancer-induced bone metastasis and manage bone health. However, these diagnostics and treatment options are not very accurate nor efficient enough to treat bone metastases and manage bone health. In this review, we present the pathogenesis of PCa-induced bone metastasis, its deleterious impacts on vital organs, the impact of metastatic PCa on bone health, treatment interventions for bone metastasis and management of bone- and skeletal-related events, and possible current and future therapeutic options for bone management in the continuum of prostate cancer disease.

Vasodilator-Stimulated Phosphoprotein Biomarkers Are Associated with Invasion and Metastasis in Colorectal Cancer.

BACKGROUND AND AIMS: The benefit of adjuvant chemotherapy for stage II colorectal cancer (CRC) patients remains unclear, emphasizing the need for improved prognostic biomarkers to identify patients at risk of metastatic recurrence. To address this unmet clinical need, we examined the expression and phosphorylation status of the vasodilator-stimulated phosphoprotein (VASP) in CRC tumor progression. VASP, a processive actin polymerase, promotes the formation of invasive membrane structures leading to extracellular matrix remodeling and tumor invasion. Phosphorylation of VASP serine (Ser) residues 157 and 239 regulate VASP function, directing subcellular localization and inhibiting actin polymerization, respectively. METHODS: The expression levels of VASP protein, pSer157-VASP, and pSer239-VASP were determined by immunohistochemistry in tumors and matched normal adjacent tissue from 141 CRC patients, divided into 2 cohorts, and the association of VASP biomarker expression with clinicopathologic features and disease recurrence was examined. RESULTS: We report that changes in VASP expression and phosphorylation were significantly associated with tumor invasion and disease recurrence. Furthermore, we disclose a novel 2-tiered methodology to maximize VASP positive and negative predictive value performance for prognostication. CONCLUSION: VASP biomarkers may serve as prognostic biomarkers in CRC and should be evaluated in a larger clinical study.

Therapeutic Challenge with a CDK 4/6 Inhibitor Induces an RB-Dependent SMAC-Mediated Apoptotic Response in Non-Small Cell Lung Cancer.

Purpose: The retinoblastoma tumor suppressor (RB), a key regulator of cell-cycle progression and proliferation, is functionally suppressed in up to 50% of non-small cell lung cancer (NSCLC). RB function is exquisitely controlled by a series of proteins, including the CyclinD-CDK4/6 complex. In this study, we interrogated the capacity of a CDK4/6 inhibitor, palbociclib, to activate RB function.Experimental Design and Results: We employed multiple isogenic RB-proficient and -deficient NSCLC lines to interrogate the cytostatic and cytotoxic capacity of CDK 4/6 inhibition in vitro and in vivo We demonstrate that while short-term exposure to palbociclib induces cellular senescence, prolonged exposure results in inhibition of tumor growth. Mechanistically, CDK 4/6 inhibition induces a proapoptotic transcriptional program through suppression of IAPs FOXM1 and Survivin, while simultaneously augmenting expression of SMAC and caspase-3 in an RB-dependent manner.Conclusions: This study uncovers a novel function of RB activation to induce cellular apoptosis through therapeutic administration of a palbociclib and provides a rationale for the clinical evaluation of CDK 4/6 inhibitors in the treatment of patients with NSCLC. Clin Cancer Res; 24(6); 1402-14. ©2018 AACR.

PARP-1 regulates DNA repair factor availability.

PARP-1 holds major functions on chromatin, DNA damage repair and transcriptional regulation, both of which are relevant in the context of cancer. Here, unbiased transcriptional profiling revealed the downstream transcriptional profile of PARP-1 enzymatic activity. Further investigation of the PARP-1-regulated transcriptome and secondary strategies for assessing PARP-1 activity in patient tissues revealed that PARP-1 activity was unexpectedly enriched as a function of disease progression and was associated with poor outcome independent of DNA double-strand breaks, suggesting that enhanced PARP-1 activity may promote aggressive phenotypes. Mechanistic investigation revealed that active PARP-1 served to enhance E2F1 transcription factor activity, and specifically promoted E2F1-mediated induction of DNA repair factors involved in homologous recombination (HR). Conversely, PARP-1 inhibition reduced HR factor availability and thus acted to induce or enhance "BRCA-ness". These observations bring new understanding of PARP-1 function in cancer and have significant ramifications on predicting PARP-1 inhibitor function in the clinical setting.

A validated quantitative assay to detect occult micrometastases by reverse transcriptase-polymerase chain reaction of guanylyl cyclase C in patients with colorectal cancer.

PURPOSE: Guanylyl cyclase C (GCC), a receptor for bacterial diarrheagenic enterotoxins, may be a prognostic and predictive marker to detect occult micrometastases in patients undergoing staging for colorectal cancer. However, quantification of GCC expression in tissues by the quantitative reverse transcription-PCR (qRT-PCR) has not undergone analytic and clinicopathologic validation. EXPERIMENTAL DESIGN: A technique to quantify GCC mRNA in tissues employing RT-PCR was developed and validated employing external calibration standards of RNA complementary to GCC. RESULTS: GCC qRT-PCR exhibited reaction efficiencies >92%, coefficients of variations <5%, linearity >6 orders of magnitude, and a limit of quantification of >25 copies of GCC cRNA. This assay confirmed that GCC mRNA was overexpressed by colorectal tumors from 41 patients, which correlated with increased GCC protein quantified by immunohistochemistry. Analyses obtained with 164 lymph nodes from patients free of cancer and 15 nodes harboring metastases established a threshold for metastatic disease of approximately 200 GCC mRNA copies/mug total RNA, with a sensitivity of 93% and specificity of 97%. GCC mRNA above that threshold was detected in 76 of 367 (approximately 21%) nodes free of disease by histopathology from 6 of 23 (26%) patients, suggesting the presence of occult micrometastases. CONCLUSIONS: Quantifying GCC mRNA in tissues by RT-PCR employing external calibration standards is analytically robust and reproducible, with high clinicopathologic sensitivity and specificity. This validated assay is being applied to approximately 10,000 lymph nodes in a prospective trial to define the sensitivity of GCC qRT-PCR for staging patients with colorectal cancer.

siRNA-Encapsulated Hybrid Nanoparticles Target Mutant K-ras and Inhibit Metastatic Tumor Burden in a Mouse Model of Lung Cancer.

There is an unmet need in the development of an effective therapy for mutant K-ras-expressing non-small-cell lung cancer (NSCLC). Although various small molecules have been evaluated, an effective therapy remains a dream. siRNAs have the potential to downregulate mutant K-ras both at the protein and mRNA levels. However, a safe and effective delivery of siRNAs to tumors remains a limitation to their translational application in the treatment of this highly debilitating disease. Here we developed a novel hybrid nanoparticle carrier for effective delivery of anti-mutant K-ras to NSCLC (AKSLHN). The ability of this treatment modality to regress lung tumors in mouse models was evaluated as a monotherapy or as a combination treatment with erlotinib. Further, the toxicity of this treatment modality to healthy tissues was evaluated, along with its ability to elicit immune/inflammatory reactions. The results suggest that this treatment modality is a promising prospect for the treatment of mutant K-ras-expressing NSCLC without any accompanying toxicity. However, further understanding of the cellular-level interaction between AHSLHN and erlotinib needs to be attained before this promising treatment modality can be brought to the bedside.

Pilot study demonstrating metabolic and anti-proliferative effects of in vivo anti-oxidant supplementation with N-Acetylcysteine in Breast Cancer.

BACKGROUND: High oxidative stress as defined by hydroxyl and peroxyl activity is often found in the stroma of human breast cancers. Oxidative stress induces stromal catabolism, which promotes cancer aggressiveness. Stromal cells exposed to oxidative stress release catabolites such as lactate, which are up-taken by cancer cells to support mitochondrial oxidative phosphorylation. The transfer of catabolites between stromal and cancer cells leads to metabolic heterogeneity between these cells and increased cancer cell proliferation and reduced apoptosis in preclinical models. N-Acetylcysteine (NAC) is an antioxidant that reduces oxidative stress and reverses stromal catabolism and stromal-carcinoma cell metabolic heterogeneity, resulting in reduced proliferation and increased apoptosis of cancer cells in experimental models of breast cancer. The purpose of this clinical trial was to determine if NAC could reduce markers of stromal-cancer metabolic heterogeneity and markers of cancer cell aggressiveness in human breast cancer. METHODS: Subjects with newly diagnosed stage 0 and I breast cancer who were not going to receive neoadjuvant therapy prior to surgical resection were treated with NAC before definitive surgery to assess intra-tumoral metabolic markers. NAC was administered once a week intravenously at a dose of 150 mg/kg and 600 mg twice daily orally on the days not receiving intravenous NAC. Histochemistry for the stromal metabolic markers monocarboxylate transporter 4 (MCT4) and caveolin-1 (CAV1) and the Ki67 proliferation assay and TUNEL apoptosis assay in carcinoma cells were performed in pre- and post-NAC specimens. RESULTS: The range of days on NAC was 14-27 and the mean was 19 days. Post-treatment biopsies showed significant decrease in stromal MCT4 and reduced Ki67 in carcinoma cells. NAC did not significantly change stromal CAV1 and carcinoma TUNEL staining. NAC was well tolerated. CONCLUSIONS: NAC as a single agent reduces MCT4 stromal expression, which is a marker of glycolysis in breast cancer with reduced carcinoma cell proliferation. This study suggests that modulating metabolism in the tumor microenvironment has the potential to impact breast cancer proliferation.

MCT1 in Invasive Ductal Carcinoma: Monocarboxylate Metabolism and Aggressive Breast Cancer.

Introduction: Monocarboxylate transporter 1 (MCT1) is an importer of monocarboxylates such as lactate and pyruvate and a marker of mitochondrial metabolism. MCT1 is highly expressed in a subgroup of cancer cells to allow for catabolite uptake from the tumor microenvironment to support mitochondrial metabolism. We studied the protein expression of MCT1 in a broad group of breast invasive ductal carcinoma specimens to determine its association with breast cancer subtypes and outcomes. Methods: MCT1 expression was evaluated by immunohistochemistry on tissue micro-arrays (TMA) obtained through our tumor bank. Two hundred and fifty-seven cases were analyzed: 180 cases were estrogen receptor and/or progesterone receptor positive (ER+ and/or PR+), 62 cases were human epidermal growth factor receptor 2 positive (HER2+), and 56 cases were triple negative breast cancers (TNBC). MCT1 expression was quantified by digital pathology with Aperio software. The intensity of the staining was measured on a continuous scale (0-black to 255-bright white) using a co-localization algorithm. Statistical analysis was performed using a linear mixed model. Results: High MCT1 expression was more commonly found in TNBC compared to ER+ and/or PR+ and compared to HER-2+ (p < 0.001). Tumors with an in-situ component were less likely to stain strongly for MCT1 (p < 0.05). High nuclear grade was associated with higher MCT1 staining (p < 0.01). Higher T stage tumors were noted to have a higher expression of MCT1 (p < 0.05). High MCT1 staining in cancer cells was associated with shorter progression free survival, increased risk of recurrence, and larger size independent of TNBC status (p < 0.05). Conclusion: MCT1 expression, which is a marker of high catabolite uptake and mitochondrial metabolism, is associated with recurrence in breast invasive ductal carcinoma. MCT1 expression as quantified with digital image analysis may be useful as a prognostic biomarker and to design clinical trials using MCT1 inhibitors.

Metformin effects on head and neck squamous carcinoma microenvironment: Window of opportunity trial.

OBJECTIVE: The tumor microenvironment frequently displays abnormal cellular metabolism, which contributes to aggressive behavior. Metformin inhibits mitochondrial oxidative phosphorylation, altering metabolism. Though the mechanism is unclear, epidemiologic studies show an association between metformin use and improved outcomes in head and neck squamous cell carcinoma (HNSCC). We sought to determine if metformin alters metabolism and apoptosis in HNSCC tumors. STUDY DESIGN: Window of opportunity trial of metformin between diagnostic biopsy and resection. Participants were patients with newly diagnosed HNSCC. Fifty patients were enrolled, and 39 completed a full-treatment course. Metformin was titrated to standard diabetic dose (2,000 mg/day) for a course of 9 or more days prior to surgery. METHODS: Immunohistochemistry (IHC) for the metabolic markers caveolin-1 (CAV1), B-galactosidase (GALB), and monocarboxylate transporter 4 (MCT4), as well as the Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) apoptosis assay and Ki-67 IHC, were performed in pre- and postmetformin specimens. Exploratory mass spectroscopy imaging (MSI) to assess lactate levels also was performed in three subjects. RESULTS: Metformin was well tolerated. The average treatment course was 13.6 days. Posttreatment specimens showed a significant increase in stromal CAV1 (P < 0.001) and GALB (P < 0.005), as well as tumor cell apoptosis by TUNEL assay (P < 0.001). There was no significant change in stromal MCT4 expression or proliferation measured by Ki67. Lactate levels in carcinoma cells were increased 2.4-fold postmetformin (P < 0.05), as measured by MSI. CONCLUSION: Metformin increases markers of reduced catabolism and increases senescence in stromal cells as well as carcinoma cell apoptosis. This study demonstrates that metformin modulates metabolism in the HNSCC microenvironment. LEVEL OF EVIDENCE: 4. Laryngoscope, 127:1808-1815, 2017.

RB Loss Promotes Prostate Cancer Metastasis.

RB loss occurs commonly in neoplasia but its contributions to advanced cancer have not been assessed directly. Here we show that RB loss in multiple murine models of cancer produces a prometastatic phenotype. Gene expression analyses showed that regulation of the cell motility receptor RHAMM by the RB/E2F pathway was critical for epithelial-mesenchymal transition, motility, and invasion by cancer cells. Genetic modulation or pharmacologic inhibition of RHAMM activity was sufficient and necessary for metastatic phenotypes induced by RB loss in prostate cancer. Mechanistic studies in this setting established that RHAMM stabilized F-actin polymerization by controlling ROCK signaling. Collectively, our findings show how RB loss drives metastatic capacity and highlight RHAMM as a candidate therapeutic target for treating advanced prostate cancer. Cancer Res; 77(4); 982-95. ©2016 AACR.

Analysis of KIT mutations in sporadic and familial gastrointestinal stromal tumors: therapeutic implications through protein modeling.

PURPOSE: Gastrointestinal stromal tumors (GIST) are characterized by expressing a gain-of-function mutation in KIT, and to a lesser extent, PDGFR. Imatinib mesylate, a tyrosine kinase inhibitor, has activity against GISTs that contain oncogenic mutations of KIT. In this study, KIT and PDGFRalpha mutation status was analyzed and protein modeling approaches were used to assess the potential effect of KIT mutations in response to imatinib therapy. EXPERIMENTAL DESIGN: Genomic DNA was isolated from GIST tumors. Exons 9, 11, 13, and 17 of c-KIT and exons 12, 14, and 18 of PDGFRalpha were evaluated for oncogenic mutations. Protein modeling was used to assess mutations within the juxtamembrane region and the kinase domain of KIT. RESULTS: Mutations in KIT exons 9, 11, and 13 were identified in GISTs with the majority of changes involving the juxtamembrane region of KIT. Molecular modeling indicates that mutations in this region result in disruption of the KIT autoinhibited conformation, and lead to gain-of-function activation of the kinase. Furthermore, a novel germ-line mutation in KIT was identified that is associated with an autosomal dominant predisposition to the development of GIST. CONCLUSIONS: We have used protein modeling and structural analyses to elucidate why patients with GIST tumors containing exon 11 mutations are the most responsive to imatinib mesylate treatment. Importantly, mutations detected in this exon and others displayed constitutive activation of KIT. Furthermore, we have found tumors that are both KIT and PDGFRalpha mutation negative, suggesting that additional, yet unidentified, abnormalities may contribute to GIST tumorigenesis.

Radiographic Kinetics of Sarcomatoid Renal Cell Carcinoma.

Renal cell carcinoma is a common entity often managed surgically with excellent survival benefits. We report a rare case of sarcomatoid renal cell carcinoma with aggressive growth kinetics after palliative resection captured radiographically.