Expression and Clinical Significance of Microtubule-Actin Cross-Linking Factor 1 in Serous Ovarian Cancer

Microtubule actin crosslinking factor 1, a brain tumor oncoprotein (Review)

Microtubule actin crosslinking factor 1 (MACF1), is a cytoskeletal protein that functions as a crosslinker between microtubules and actin filaments, with early studies expanding the role of this spectraplakin protein to the central nervous system and Wnt signaling. In the early 2000's, genetic alterations of MACF1 were identified in several cancers suggesting that this cytoskeletal crosslinker was involved in tumor development and progression, while preclinical studies provided evidence that MACF1 is a potential diagnostic and prognostic biomarker and therapeutic target in glioblastomas, a central nervous system cancer derived from astrocytes and neural progenitor stem cells. Furthermore, investigations in glioblastomas demonstrated that genetic inhibitory targeting of this spectraplakin protein alone and in combination with DNA damaging agents had synergistic antitumorigenic effects. The established role of MACF1 in Wnt signaling, a known mechanistic driver of central nervous system development and pro-tumorigenic cell behavior in glioblastomas, provide a premise for addressing the potential of this spectraplakin protein as a novel oncoprotein in cancers with origins in the nervous system. The present review provides a summary of the role and function of MACF1 in the central nervous system, Wnt signaling and cancer development, specifically as an oncoprotein that underlie the transformation and oncogenic properties of glioblastomas.

LRRC1 knockdown downregulates MACF1 to inhibit the malignant progression of acute myeloid leukemia by inactivating β-catenin/c-Myc signaling

Acute myeloid leukemia (AML) is a hematologic disease associated with genetic abnormalities. This study aimed to explore the role of leucine-rich repeat-containing protein 1 (LRRC1) in the malignant activities of AML and to reveal the molecular mechanism related to microtubule actin cross-linking factor 1 (MACF1). GEPIA database was used to analyze the expression of LRRC1 in bone marrow tissues of AML patients and the correlation between LRRC1 expression and survival analysis. LRRC1 was knocked down to assess the change of AML cell proliferation, cell cycle and apoptosis using CCK-8 assay and flow cytometry. Besides, the contents of extracellular acidification and oxygen consumption rates were measured to evaluate the glycolysis. Additionally, the interaction between LRRC1 and MACF1 predicted by MEM database and was verified by co-immunoprecipitation (Co-IP) assay. Then, MACF1 was overexpressed to conduct the rescue experiments. Expression of proteins in β-catenin/c-Myc signaling was detected by western blot. Finally, AML xenograft mouse model was established to observe the impacts of LRRC1 silencing on the tumor development. Notably upregulated LRRC1 expression was observed in bone marrow tissues of AML patients and AML cells, and patients with the higher LRRC1 expression displayed the lower overall survival. LRRC1 depletion promoted cell cycle arrest and apoptosis and inhibited the glycolysis. Co-IP confirmed the interaction between LRRC1 and MACF1. MACF1 upregulation relieved the impacts of LRRC1 knockdown on the malignant activities of AML cells. Moreover, LRRC1 silencing inhibited the development of xenograft tumor growth of HL-60 cells in nude mice, suppressed MACF1 expression and inactivated the β-catenin/c-Myc signaling. Collectively, LRRC1 knockdown suppressed proliferation, glycolysis and promoted apoptosis in AML cells by downregulating MACF1 expression to inactivate β-catenin/c-Myc signaling.

Pan-Cancer Analysis for Immune Cell Infiltration and Mutational Signatures Using Non-Negative Canonical Correlation Analysis

Mutational signatures indicate the mutational processes and substitution patterns in cancer cell genomes. However, the functional consequences of mutational signatures remain unclear, and there have been no comprehensive systematic studies to examine the relationships between the mutational signatures and the immune cell infiltration. Here, the relationship between mutational signatures and immune cell infiltration using non-negative canonical correlation analysis based on 8927 patients across 25 tumor types was investigated. By inspecting mutational signatures with the maximal coefficients determined by the non-negative canonical correlation analysis, the study identified mutational signatures related to immune cell infiltration composed of tumor microenvironments. The analysis was validated by showing that the genes associated with the identified mutational signatures were linked to overall survival by a Kaplan–Meier curve and a log-rank test and were mainly related to immunity by gene set enrichment analysis. These results will help expand our knowledge of tumor biology and recognize the functional roles and associations of immune systems with mutational signatures.

Co-Overexpression of GRK5/ACTC1 Correlates With the Clinical Parameters and Poor Prognosis of Epithelial Ovarian Cancer

Background: The prognosis of epithelial ovarian cancer (EOC) is poor, and the present prognostic predictors of EOC are neither sensitive nor specific.

Objective: The aim of this study was to search the prognostic biomarkers of EOC and to investigate the expression of G protein-coupled receptor kinase 5 (GRK5) and actin alpha cardiac muscle 1 (ACTC1) in EOC tissues (both paraffin-embedded and fresh-frozen tissues) and to explore their association with clinicopathological parameters and prognostic value in patients with EOC.

Methods: A total of 172 paraffin-embedded cancer tissues of EOC patients diagnosed and operated at the memorial hospital of Sun Yat-sen University between December 2009 and March 2017 and 41 paratumor tissues were collected and the expression of GRK5 and ACTC1 was examined using immunohistochemistry. Furthermore, 16 fresh-frozen EOC tissues and their matched paratumor tissues were collected from the Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, between August 2013 and November 2019 and subjected to reverse-transcription quantitative PCR analysis to detect the mRNA expression of GRK5 and ACTC1.

Results: The expression of GRK5 and ACTC1 was both higher in cancer tissues than in paratumor tissues. GRK5 expression was positively correlated with ACTC1 expression. In addition, GRK5, ACTC1, and GRK5/ACTC1 expression was associated with the recurrence-free survival and overall survival of EOC patients. Furthermore, multivariate logistic regression analysis indicated that GRK5+/ACTC1+ co-expression, intestinal metastasis, postoperative chemotherapy, platinum resistance, and hyperthermic intraperitoneal chemotherapy were independent prognostic factors of EOC.

Conclusion: GRK5 and ACTC1 are both upregulated in EOC compared with those in paratumor tissues. The co-expression of GRK5+/ACTC1+ rather than GRK5 or ACTC1 is an independent prognostic biomarker of EOC.