Serine-threonine Kinase Receptor-Associated Protein is a Critical Mediator of APC Mutation-Induced Intestinal Tumorigenesis Through a Feed-Forward Mechanism.

BACKGROUND & AIMS: Inactivation of the Apc gene is a critical early event in the development of sporadic colorectal cancer (CRC). Expression of serine-threonine kinase receptor-associated protein (STRAP) is elevated in CRCs and is associated with poor outcomes. We investigated the role of STRAP in Apc mutation-induced intestinal tumor initiation and progression. METHODS: We generated Strap intestinal epithelial knockout mice (StrapΔIEC) by crossing mice containing floxed alleles of Strap (Strapfl/fl) with Villin-Cre mice. Then we generated ApcMin/+;Strapfl/fl;Vill-Cre (ApcMin/+;StrapΔIEC) mice for RNA-sequencing analyses to determine the mechanism of function of STRAP. We used human colon cancer cell lines (DLD1, SW480, and HT29) and human and mouse colon tumor-derived organoids for STRAP knockdown and knockout and overexpression experiments. RESULTS: Strap deficiency extended the average survival of ApcMin/+ mice by 80 days and decreased the formation of intestinal adenomas. Expression profiling revealed that the intestinal stem cell signature, the Wnt/ß-catenin signaling, and the MEK/ERK pathway are down-regulated in Strap-deficient adenomas and intestinal organoids. Correlation studies suggest that these STRAP-associated oncogenic signatures are conserved across murine and human colon cancer. STRAP associates with MEK1/2, promotes binding between MEK1/2 and ERK1/2, and subsequently induces the phosphorylation of ERK1/2. STRAP activated Wnt/ß-catenin signaling through MEK/ERK-induced phosphorylation of LRP6. STRAP was identified as a target of mutated Apc and Wnt/ß-catenin signaling as chromatin immunoprecipitation and luciferase assays revealed putative binding sites of the ß-catenin/TCF4 complex on the Strap promoter. CONCLUSIONS: STRAP is a target of, and is required in, Apc mutation/deletion-induced intestinal tumorigenesis through a novel feed-forward STRAP/MEK-ERK/Wnt-ß-catenin/STRAP regulatory axis.

Serine Threonine Kinase Receptor-Associated Protein Deficiency Impairs Mouse Embryonic Stem Cells Lineage Commitment Through CYP26A1-Mediated Retinoic Acid Homeostasis.

Retinoic acid (RA) signaling is essential for the differentiation of embryonic stem cells (ESCs) and vertebrate development. RA biosynthesis and metabolism are controlled by a series of enzymes, but the molecular regulators of these enzymes remain largely obscure. In this study, we investigated the functional role of the WD-domain protein STRAP (serine threonine kinase receptor-associated protein) in the pluripotency and lineage commitment of murine ESCs. We generated Strap knockout (KO) mouse ESCs and subjected them to spontaneous differentiation. We observed that, despite the unchanged characteristics of ESCs, Strap KO ESCs exhibited defects for lineage differentiation. Signature gene expression analyses revealed that Strap deletion attenuated intracellular RA signaling in embryoid bodies (EBs), and exogenous RA significantly rescued this deficiency. Moreover, loss of Strap selectively induced Cyp26A1 expression in mouse EBs, suggesting a potential role of STRAP in RA signaling. Mechanistically, we identified putative Krüppel-like factor 9 (KLF9) binding motifs to be critical in the enhancement of non-canonical RA-induced transactivation of Cyp26A1. Increased KLF9 expression in the absence of STRAP is partially responsible for Cyp26A1 induction. Interestingly, STRAP knockdown in Xenopus embryos influenced anterior-posterior neural patterning and impaired the body axis and eye development during early Xenopus embryogenesis. Taken together, our study reveals an intrinsic role for STRAP in the regulation of RA signaling and provides new molecular insights for ESC fate determination. Stem Cells 2018;36:1368-1379.

The Potential Utility of Acceptance and Commitment Therapy (ACT) for Reducing Stress and Improving Wellbeing in Cancer Patients in Kolkata.

As soon as a patient comes to know that he/she has cancer, the stress starts and psychological intervention is required. The authors assessed how well a cancer patient can manage stress over the course of the psychological intervention. Data was collected among 107 patients during pre and post intervention and at 2 months follow-up. Intervention was required to measures include acceptance of the disease, managing stress, well -being, and meaning of life. Finally, effects of acceptance and commitment therapy (ACT) were defined in acceptance measured in terms of a significant difference between pre and post intervention scores in the meaning of life and the acceptance level. This acceptance and commitment therapy can be an effective intervention approach for cancer patients that increases acceptance regarding disease and simultaneously leads to improvement in the meaning of life.

Social Emotion Recognition, Social Functioning and Suicidal Behaviour in Breast Cancer Patients in India.

AIMS: lack of emotional connection and poor social support are the influential factors for developing suicidal ideation. Studies have established social cognitive deficit in patients with depression, autism, schizophrenia. However, no study so far has investigated about the status social factors in breast cancer patients who often suffer from suicidal thoughts. We hypothesized the relationship between social emotion recognition, social support and suicidal thoughts in breast cancer patients. METHOD: The cross-sectional study was conducted at the Oncology department of a multi-speciality hospital in Kolkata. There were 176 breast cancer patients: depressed breast cancer patients having suicidal idea (Group-I; N=81), non-suicidal idea depressed breast cancer individuals (Group-II; N=48), and breast cancer with no psychiatric history (Group-III; N=47). Baron-Cohen's Reading the Mind in the Eyes Test and Multidimensional Perceived Social was used for comparing the performance of social support and mind reading abilities in these three groups. RESULTS: All groups performed poorly compared to GroupIII (29.1 ± 1.27). RMT scores for study Groups I and II were observed as (17.9 ± 0.14) vs (20.32 ± 061). There was an interaction between suicidal thoughts and depression, was also significant ((F=69.5, sig=0.001). this difference remained significant after controlling for demographic variables. CONCLUSIONS: Suicidal ideation was associated with impaired social emotion recognition and social support. This affects their ability to prop up for social support. This needs to be signified urgently to make sure a better quality of life. KEY WORDS: Breast cancer, theory of mind, suicidal thoughts and depression.

Theory of mind deficit in women with breast cancer and depression: A comparative study.

Background: Studies have established that Theory of Mind (ToM) is impaired in patients with depression, but few studies have investigated the status of ToM in breast cancer patients who often suffer from depression. Our objective was to compare the ToM deficits in women with breast cancer with and without depression with a control group. Methods: The study was conducted at the Oncology department of a multi-speciality hospital in Kolkata. It was a cross sectional matched control study. We compared the ToM performance of women with breast cancer and depression (N=39), breast cancer without depression (N=63) and a healthy control group (N=34) using the widely used ToM task, Reading the Mind in the Eyes test (Eyes Test). Depression was diagnosed using Mini - International Neuropsychiatric Interview following International Classification of Diseases - 10th edition guidelines. Chi-square and one-way analysis of variances was done. Results: Both groups of patients had greater impairment in ToM compared to healthy controls (p<0.05). Among breast cancer patients, presence of depression predicted even greater impairment of ToM (p<0.05). Lower income, less education and not being in any occupation other than homemaking were associated with greater ToM impairment across all groups (p <0.05). Conclusion: Breast cancer patients suffering from depression may have an additional burden of impaired social cognition, which may reduce their ability to shore up social support when it is most required. This needs to be addressed urgently to ensure better quality of life.

Antimetastatic role of Smad4 signaling in colorectal cancer.

BACKGROUND & AIMS: Transforming growth factor (TGF)-beta signaling occurs through Smads 2/3/4, which translocate to the nucleus to regulate transcription; TGF-beta has tumor-suppressive effects in some tumor models and pro-metastatic effects in others. In patients with colorectal cancer (CRC), mutations or reduced levels of Smad4 have been correlated with reduced survival. However, the function of Smad signaling and the effects of TGF-beta-receptor kinase inhibitors have not been analyzed during CRC metastasis. We investigated the role of TGF-beta/Smad signaling in CRC progression. METHODS: We evaluated the role of TGF-beta/Smad signaling on cell proliferation, migration, invasion, tumorigenicity, and metastasis in Smad4-null colon carcinoma cell lines (MC38 and SW620) and in those that transgenically express Smad4. We also determined the effects of a TGF-beta-receptor kinase inhibitor (LY2109761) in CRC tumor progression and metastasis in mice. RESULTS: TGF-beta induced migration/invasion, tumorigenicity, and metastasis of Smad4-null MC38 and SW620 cells; incubation with LY2109761 reversed these effects. In mice, LY2109761 blocked metastasis of CRC cells to liver, inducing cancer cell expression of E-cadherin and reducing the expression of the tumorigenic proteins matrix metalloproteinase-9, nm23, urokinase plasminogen activator, and cyclooxygenase-2. Transgenic expression of Smad4 significantly reduced the oncogenic potential of MC38 and SW620 cells; in these transgenic cells, TGF-beta had tumor suppressor, rather than tumorigenic, effects. CONCLUSIONS: TGF-beta/Smad signaling suppresses progression and metastasis of CRC cells and tumors in mice. Loss of Smad4 might underlie the functional shift of TGF-beta from a tumor suppressor to a tumor promoter; inhibitors of TGF-beta signaling might be developed as CRC therapeutics.

STRAP regulates alternative splicing fidelity during lineage commitment of mouse embryonic stem cells.

Alternative splicing (AS) is involved in cell fate decisions and embryonic development. However, regulation of these processes is poorly understood. Here, we have identified the serine threonine kinase receptor-associated protein (STRAP) as a putative spliceosome-associated factor. Upon Strap deletion, there are numerous AS events observed in mouse embryoid bodies (EBs) undergoing a neuroectoderm-like state. Global mapping of STRAP-RNA binding in mouse embryos by enhanced-CLIP sequencing (eCLIP-seq) reveals that STRAP preferably targets transcripts for nervous system development and regulates AS through preferred binding positions, as demonstrated for two neuronal-specific genes, Nnat and Mark3. We have found that STRAP involves in the assembly of 17S U2 snRNP proteins. Moreover, in Xenopus, loss of Strap leads to impeded lineage differentiation in embryos, delayed neural tube closure, and altered exon skipping. Collectively, our findings reveal a previously unknown function of STRAP in mediating the splicing networks of lineage commitment, alteration of which may be involved in early embryonic lethality in mice.

Genotype-phenotype effects of Bmpr2 mutations on disease severity in mouse models of pulmonary hypertension.

More than 350 mutations in the type-2 BMP (bone morphogenetic protein) receptor, BMPR2, have been identified in patients with heritable pulmonary arterial hypertension (HPAH). However, only 30% of BMPR2 mutation carriers develop PAH, and we cannot predict which of these carriers will develop clinical disease. One possibility is that the nature of the BMPR2 mutation affects disease severity. This hypothesis has been difficult to test clinically, given the rarity of HPAH and the complexity of the confounding genetic and environmental risk factors. To test this hypothesis, therefore, we evaluated the susceptibility to experimental pulmonary hypertension (PH) of mice carrying different HPAH-associated Bmpr2 mutations on otherwise identical genetic backgrounds. Mice with Bmpr2ΔEx4-5 mutations (Bmpr2+/-), in which the mutant protein is not expressed, develop less severe PH in response to hypoxia or hypoxia with vascular endothelial growth factor receptor inhibition than mice with an extracellular-domain Bmpr2ΔEx2 mutation (Bmpr2ΔEx2/+), in which the mutant protein is expressed. This was associated with a marked decrease in stabilizing phosphorylation of threonine 495 endothelial nitric oxide synthase (pThr495 eNOS) in Bmpr2ΔEx2/+ compared to wild-type and Bmpr2+/- mouse lungs. These findings provide the first experimental evidence that BMPR2 mutation types influence the severity of HPAH and suggest that patients with BMPR2 mutations who express mutant BMPR2 proteins by escaping non-sense-mediated messenger RNA decay (NMD- mutations) will develop more severe disease than HPAH patients with NMD+ mutations who do not express BMPR2 mutant proteins. Since decreased levels of pThr495 eNOS are associated with increased eNOS uncoupling, our data also suggest that this effect may result from defects in eNOS function.

Novel role of STRAP in progression and metastasis of colorectal cancer through Wnt/ß-catenin signaling.

Serine-Threonine Kinase Receptor-Associated Protein (STRAP) interacts with a variety of proteins and influences a wide range of cellular processes. Aberrant activation of Wnt/ß-catenin signaling has been implicated in the development of colorectal cancer (CRC). Here, we show the molecular mechanism by which STRAP induces CRC metastasis by promoting ß-catenin signaling through its stabilization. We have genetically engineered a series of murine and human CRC and lung cancer cell lines to investigate the effects of STRAP on cell migration and invasion in vitro, and on tumorigenicity and metastasis in vivo. Downregulation of STRAP inhibits invasion, tumorigenicity, and metastasis of CRC cells. Mechanistically, STRAP binds with GSK-3ß and reduces the phosphorylation, ubiquitylation, and degradation of ß-catenin through preventing its binding to the destruction complex. This leads to an inhibition of Wnt/ß-catenin signaling and reduction in the expression of downstream targets, such as Cyclin D1, matrix metalloproteinases 2 and 9, and ß-TrCP. In human CRC specimens, higher STRAP expression correlates significantly with ß-catenin expression with increased nuclear levels (R =0.696, p < .0001, n =128). Together, these results suggest that STRAP increases invasion and metastasis of CRC partly through inhibiting ubiquitin-dependent degradation of ß-catenin and promoting Wnt/ß-catenin signaling.

An epigenetic auto-feedback loop regulates TGF-ß type II receptor expression and function in NSCLC.

The downregulation of transforming growth factor-ß (TGF-ß) type II receptor (TßRII) expression and function plays a pivotal role in the loss of the TGF-ß-induced tumor suppressor function that contributes to lung cancer progression. The aberrant expression of miRNAs has been shown to be involved in the regulation of oncogenes and tumor suppressor genes. Our current study involving miRNA microarray, northern blot and QRT-PCR analysis shows an inverse correlation between miR-20a and TßRII expression in non-small cell lung cancer (NSCLC) tissues and cell lines. Stable expression of miR-20a downregulates TßRII in lung epithelial cells which results in an inhibition of TGF-ß signaling and attenuation of TGF-ß-induced cell growth suppression and apoptosis. Stable knock down of miR-20a increases TßRII expression and inhibits tumorigenicity of lung cancer cells in vivo. Oncogene c-Myc promotes miR-20a expression by activating its promoter leading to downregulation of TßRII expression and TGF-ß signaling. MiR-145, which is upregulated by TGF-ß, inhibits miR-20a expression by targeting c-Myc and upregulates TßRII expression. These correlations among miRNAs and cellular proteins are supported by TCGA public database using NSCLC specimens. These results suggest a novel mechanism for the loss of TßRII expression and TGF-ß-induced tumor suppressor functions in lung cancer through a complex auto-feedback loop TGF-ß/miR-145/c-Myc/miR-20a/TßRII.

Elucidating the mechanism of regulation of transforming growth factor ß Type II receptor expression in human lung cancer cell lines.

Lung carcinogenesis in humans involves an accumulation of genetic and epigenetic changes that lead to alterations in normal lung epithelium, to in situ carcinoma, and finally to invasive and metastatic cancers. The loss of transforming growth factor ß (TGF-ß)-induced tumor suppressor function in tumors plays a pivotal role in this process, and our previous studies have shown that resistance to TGF-ß in lung cancers occurs mostly through the loss of TGF-ß type II receptor expression (TßRII). However, little is known about the mechanism of down-regulation of TßRII and how histone deacetylase (HDAC) inhibitors (HDIs) can restore TGF-ß-induced tumor suppressor function. Here we show that HDIs restore TßRII expression and that DNA hypermethylation has no effect on TßRII promoter activity in lung cancer cell lines. TGF-ß-induced tumor suppressor function is restored by HDIs in lung cancer cell lines that lack TßRII expression. Activation of mitogen-activated protein kinase/extracellular signal-regulated kinase pathway by either activated Ras or epidermal growth factor signaling is involved in the down-regulation of TßRII through histone deacetylation. We have immunoprecipitated the protein complexes by biotinylated oligonucleotides corresponding to the HDI-responsive element in the TßRII promoter (-127/-75) and identified the proteins/factors using proteomics studies. The transcriptional repressor Meis1/2 is involved in repressing the TßRII promoter activity, possibly through its recruitment by Sp1 and NF-YA to the promoter. These results suggest a mechanism for the downregulation of TßRII in lung cancer and that TGF-ß tumor suppressor functions may be restored by HDIs in lung cancer patients with the loss of TßRII expression.

Serine threonine receptor-associated protein (STRAP) plays a role in the maintenance of mesenchymal morphology.

The stromal tissue, made of extracellular matrix and mesenchymal cells, is vital for the functional design of all complex tissues. Fibroblasts are key components of stromal tissue and play a crucial role during organ development, wound repair, angiogenesis and fibrosis. We have previously reported the identification of a novel WD-domain protein, STRAP(1) that inhibits transforming growth factor-beta (TGF-beta) signaling and enhances tumorigenicity via TGF-beta-dependent and TGF-beta-independent mechanisms. Here, we report, for the first time, that deletion of STRAP from Mouse Embryonic Fibroblasts (MEFs) results in a loss of mesenchymal morphology. These cells lose their spindle shape and exhibit features of an epithelial morphology. Gene expression profiling has confirmed that deletion of STRAP affects expression of sets of genes important for diverse functions including cell-cell adhesion and cell polarization, and upregulates E-cadherin expression leading to the formation of adherens junctions, subsequent localization of beta-catenin to the cell membrane and downregulation of the mesenchymal markers like LEF1 (lymphoid enhancer-binding factor 1). Upregulation of WT1 (Wilms tumor homolog 1) in STRAP null MEFs plays a role in E-cadherin induction. Finally, stable expression of STRAP in these cells results in a loss of WT1 and E-cadherin expressions, and a reversal from epithelial to the mesenchymal morphology. Thus, these results provide a novel TGF-beta-independent function of STRAP and describe a mechanism for the role of STRAP in the maintenance of mesenchymal morphology.