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Colorectal cancer (CRC) is the fourth most common cancer type globally. Investigating the signaling pathways that maintain cancer cell phenotype can identify new biomarkers for targeted therapy. Aberrant transforming growth factor-β (TGFβ) signaling has been implicated in CRC progression, however, the exact mechanism by which TGFβ exerts its function is still being unraveled. Herein, we investigated TAGLN expression, prognostic value, and its regulation by TGFβ in CRC. While TAGLN was generally found to be downregulated in CRC, elevated expression of TAGLN was associated with advanced CRC stage and predicted poor overall survival (hazard ratio (HR) = 1.8, log-rank test P-value = 0.014) and disease-free survival (HR = 1.6, log-rank test P-value = 0.046), hence implicating TAGLN as poor prognostic factor in CRC. Forced expression of TAGLN was associated with enhanced CRC cell proliferation, clonogenic growth, cell migration and in vivo tumor formation in immunocompromised mice, while targeted depletion of TAGLN exhibited opposing biological effects. Global gene expression profiling of TAGLN-overexpressing or TAGLN-deficient CRC cell lines revealed deregulation of multiple cancer-related genes and signaling pathways. Transmission electron microscopy (TEM) revealed ultrastructural changes due to loss of TAGLN, including disruption of actin cytoskeleton organization and aberrant actin filament distribution. Hierarchical clustering, principle component, and ingenuity pathway analyses revealed distinct molecular profile associated with TAGLNhigh CRC patients with remarkable activation of a number of mechanistic networks, including SMARCA4, TGFβ1, and P38 MAPK. The P38 MAPK was the top predicted upstream regulator network promoting cell movement through regulation of several intermediate molecules, including TGFβ1. Concordantly, functional categories associated with cellular movement and angiogenesis were also enriched in TAGLNhigh CRC, supporting a model for the molecular mechanisms linking TGFβ-induced upregulation of TAGLN and CRC tumor progression and suggesting TAGLN as potential prognostic marker associated with advanced CRC pathological stage.

Despite recent advances in cancer management and therapy, resistance to cytotoxic medications remains a major clinical challenge; hence, combination-based anti-cancer treatment regimens are currently gaining momentum. PTC-209 reduced BMI1 protein expression, while palbociclib inhibited CDK4, Rb, and pRbSer795 protein expression in MDA-MB-231 cells. PTC-209 and palbociclib exhibited dose-dependent cytotoxic effects against MDA-MB-231 (breast), HCT116 (colon), and PC-3 (prostate) models, which was more profound in the combination group. Transcriptome and pathway analyses revealed inhibition of insulin signaling, focal adhesion, DNA damage response, and Wnt/pluripotency signaling pathways as well as cell proliferation, and cellular movement functional categories by PTC-209. Transcriptome and pathway analyses revealed palbociclib to mainly affect cell cycle progression and survival. Upstream analysis identified several networks affected by PTC-209 (EZH2, IFNB1, TRIB3, EGFR, SREBF1, IL1A, ERG, TGFB1, MAX, MNT) and palbociclib (RABL6, MITF, RARA, TAL1, AREG, E2F3, FOXM1, ESR1, ERBB2, and E2F). PTC-209 and palbociclib reduced colony and sphere formation, cell migration, and cell viability, which was further enhanced in the combination group. Concordantly, combination of PTC-209 and palbociclib exhibited more profound effects on MDA-MB-231 tumor formation in vivo. Our data suggest concurrent targeting of BMI1 and CDK4/CDK6 might provide novel therapeutic opportunity for breast, colon, and prostate cancer.

Regenerative medicine is a novel approach for treating conditions in which enhanced bone regeneration is required. We identified transgelin (TAGLN), a transforming growth factor beta (TGFβ)-inducible gene, as an upregulated gene during in vitro osteoblastic and adipocytic differentiation of human bone marrow-derived stromal (skeletal) stem cells (hMSC). siRNA-mediated gene silencing of TAGLN impaired lineage differentiation into osteoblasts and adipocytes but enhanced cell proliferation. Additional functional studies revealed that TAGLN deficiency impaired hMSC cell motility and in vitro transwell cell migration. On the other hand, TAGLN overexpression reduced hMSC cell proliferation, but enhanced cell migration, osteoblastic and adipocytic differentiation, and in vivo bone formation. In addition, deficiency or overexpression of TAGLN in hMSC was associated with significant changes in cellular and nuclear morphology and cytoplasmic organelle composition as demonstrated by high content imaging and transmission electron microscopy that revealed pronounced alterations in the distribution of the actin filament and changes in cytoskeletal organization. Molecular signature of TAGLN-deficient hMSC showed that several genes and genetic pathways associated with cell differentiation, including regulation of actin cytoskeleton and focal adhesion pathways, were downregulated. Our data demonstrate that TAGLN has a role in generating committed progenitor cells from undifferentiated hMSC by regulating cytoskeleton organization. Targeting TAGLN is a plausible approach to enrich for committed hMSC cells needed for regenerative medicine application.