KAP1 (TRIM28) is a transcriptional regulator in embryonic development that controls stem cell self-renewal, chromatin organization and the DNA damage response, acting as an essential co-repressor for KRAB family zinc finger proteins (KRAB-ZNF). To gain insight into the function of this large gene family, we developed an antibody that recognizes the conserved zinc fingers linker region (ZnFL) in multiple KRAB-ZNF. Here we report that the expression of many KRAB-ZNF along with active SUMOlyated KAP1 is elevated widely in human breast cancers. KAP1 silencing in breast cancer cells reduced proliferation and inhibited the growth and metastasis of tumor xenografts. Conversely, KAP1 overexpression stimulated cell proliferation and tumor growth. In cells where KAP1 was silenced, we identified multiple downregulated genes linked to tumor progression and metastasis, including EREG/epiregulin, PTGS2/COX2, MMP1, MMP2 and CD44, along with downregulation of multiple KRAB-ZNF proteins. KAP1-dependent stabilization of KRAB-ZNF required direct interactions with KAP1. Together, our results show that KAP1-mediated stimulation of multiple KRAB-ZNF contributes to the growth and metastasis of breast cancer.

Despite the low prevalence of activating point mutation of RAS or RAF genes, the RAS-extracellular signal-regulated kinase (ERK) pathway is implicated in breast cancer pathogenesis. Indeed, in triple-negative breast cancer (TNBC), there is recurrent genetic alteration of pathway components. Using short hairpin RNA (shRNA) methods, we observed that the zinc finger transcription factor Krüppel-like factor 4 ( KLF4

Tumor cells inherit from their normal precursors an extensive stress response machinery that is critical for survival in response to challenges including oxidative stress, wounding and shear stress. Kruppel-like transcription factors, including KLF4 and KLF5, are rarely affected by genetic alteration during tumorigenesis, but compose key components of the stress response machinery in normal and tumor cells and interact with critical survival pathways, including RAS, p53, survivin and the BCL2 family of cell death regulators. Within tumor cells KLF4 and KLF5 play key roles in tumor cell fate, regulating cell proliferation, cell survival and the tumor initiating properties of cancer stem-like cells. These factors can be preferentially expressed in embryonic stem cells or cancer stem-like cells. Indeed, specific KLFs represent key components of a cross regulating pluripotency network in embryonic stem cells, and induce pluripotency when coexpressed in adult cells with other Yamanaka factors. Suggesting analogies between this pluripotency network and the cancer cell adaptive reprogramming that occurs in response to targeted therapy, recent studies link KLF4 and KLF5 to adaptive prosurvival signaling responses induced by HER2-targeted therapy. We review literature supporting KLFs as shared mechanisms in stress adaptation and cellular reprogramming and address the therapeutic implications.

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Reaction of monosubstituted allenes with aryldiazoacetate esters under dirhodium tetracarboxylate catalysis led to alkylidene cyclopropane products in 80-90% ee. Monosubstituted alkyl- and arylallene substrates gave 60-75% yield under standard conditions, while yields for 1,1-disubstituted allenes were significantly lower. Cyclopropanation of 1-methyl-1-(trimethylsilyl)allene proceeded in higher yield than other 1,1-disubstituted substrates, suggesting rate enhancement mediated by a significant beta-silicon effect.

Background: Despite occurring commonly, the prognoses of second early-stage non–small cell lung cancers (NSCLC) are not well known. Methods: The authors retrospectively reviewed the charts of inoperable patients who underwent thoracic stereotactic body radiation therapy (SBRT) from February 2007 to April 2019. Those with previous small cell lung cancers or SBRT treatments for tumors other than NSCLC were excluded. Multivariate Cox regression and a matched pair cohort analyses evaluated the prognoses of patients undergoing definitive SBRT for a new second primary. Results: Of 438 patients who underwent definitive SBRT for NSCLC, 84 had previously treated NSCLC. Univariate log-rank tests identified gender, Karnofksy performance status (KPS), prior lung cancer, anticoagulation use, and history of heart disease to correlate with overall survival (OS) (P<0.05). These factors were incorporated into a multivariate Cox regression model that demonstrated female sex (P=0.004, hazard ratio [HR]=0.68), KPS (P<0.001, HR=2.0), and prior lung cancer (P=0.049, HR=0.7) to be significantly associated with OS. A similar approach found only gender (P=0.017, HR=0.64) and tumor stage (P=0.02, HR=1.7) to correlate with relapse-free survival. To support the Cox regression analysis, propensity score matching was performed using gender, age, KPS, tumor stage, history of heart disease, and anticoagulation use. Kaplan-Meier survival analysis within the matched pairs found prior lung cancer to be associated with improved OS (P=0.011), but not relapse-free survival (P=0.44). Conclusions: Compared with initial lung cancer SBRT inoperable cases, ablative radiotherapy for new primaries was associated with improved OS. Physicians should not be dissuaded from offering SBRT to such patients.

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Perforation of the esophagus is a very rare complication of metallic esophageal stent insertion. Two cases are presented in which esophageal perforations were caused by the sharp ends of metallic stents impinging on the esophageal wall. In retrospect, both perforations might have been prevented by additional stent insertion.