Restoration of MARCK enhances chemosensitivity in cancer

Abstract

Purpose Increased ATP-binding-cassette (ABC) transporter activity is a major cause of chemotherapy resistance in cancer. The ABC transporter family member ABCB1 is often overexpressed in colorectal cancer (CRC). Phosphatidylinositol-4,5-bisphosphat (PI(4,5)P 2)-dependent pathways are involved in the regulation of ABCB1 function. The protein Myristoylated Alanine-Rich C-Kinase Substrate (MARCKS) is a pivotal regulator of PI(4,5)P 2 and inactivated in many CRC cancers via genetic deletion or hyperphosphorylation. Therefore, MARCKS may critically impact ABCB1. Methods CRC samples as well as CRC cell lines were tested for a connection between MARCKS and ABCB1 via immunofluorescence and Western-blot analysis. ABCB1 function was studied via calcein influx assay under treatment with known ABCB1 inhibitors (verapamil, tariquidar) as well as the kinase inhibitor bosutinib. ABCB1 internalization and MARCKS translocation was analyzed via confocal microscopy exploiting the endocytosis inhibitors chlorpromazine and dynasore. Abundance of PI(4,5)P 2 was monitored by intramolecular fluorescence resonance energy transfer (FRET). Reproductive cell survival was studied via colorimetric WST-1 and clonogenic assays in combination with exposure to the chemotherapeutics doxorubicin and 5-fuorouracil (5-FU). Results We found increased ABCB1 expression in MARCKS negative CRC patient tumor samples and established CRC cell lines. Mechanistically, the reconstitution of MARCKS function via recombinant expression or the pharmacological inhibition of MARCKS phosphorylation led to a substantial decrease in ABCB1 activity. In CRC cells, bosutinib treatment resulted in a MARCKS translocation from the cytosol to the plasma membrane, while simultaneously, ABCB1 was relocated to intracellular compartments. Inhibition of MARCKS phosphorylation via bosutinib rendered cells more sensitive to the chemotherapeutics doxorubicin and 5-FU. Conclusions Cells devoid of MARCKS function showed incomplete ABCB1 internalization, leading to higher ABCB1 activity enhancing chemoresistance. Vice versa our data suggest the prevention of MARCKS inhibition by reversing hyperphosphorylation or genomic restoration after deletion as two promising approaches to overcome tumor cell resistance towards chemotherapeutic ABCB1 substrates.

Pathophysiological roles of myristoylated alanine-rich C-kinase substrate (MARCKS) in hematological malignancies

“…Whereas the functional influence of MARCKS on cellular systems extends beyond developmental and maintenance workflow, numerous studies have now indicated that anomalous expression of MARCKS is often associated with several cancers. Extensive data suggest that dysregulated MARCKS expression drives the development and progression of several solid tumors including melanoma [ 11 , 102 , 103 ], glioma [ 12 , 104 , 105 ], renal cell carcinoma [ 106 ], lung cancer [ 107 – 109 ], colorectal cancer [ 110 , 111 ], liver cancer [ 13 , 112 ], and breast cancer [ 113 – 115 ]. Similarly, aberrant MARCKS has been observed to contribute to increased cell proliferation, reduced cell death, higher rates of cell migration, invasion, and motility, and malignant transformation in several hematological malignancies (Table 1 ).…”

“…Within solid cancers, MARCKS has commonly been identified with a cancer-promoting role in breast cancer [ 113 – 115 ], lung cancer [ 107 – 109 ], melanoma [ 11 , 103 ], glioma [ 104 ], renal cell carcinoma [ 106 ], and liver cancer [ 13 , 112 ]. Contrarily, several research groups have observed that higher expression of MARCKS inhibits cancer development and progression in colorectal cancer [ 110 , 147 ], hepatocellular carcinoma [ 148 ], melanoma [ 149 ], and glioma [ 12 , 105 , 150 ]. Such a dual role of MARCKS has been observed in blood cancers as well.…”

Detection of Immune Microenvironment Changes and Immune‐Related Regulators in Langerhans Cell Histiocytosis Bone Metastasis

“…In our research, by enrichment analysis and partial correlation analysis, we found that MARCKS was highly correlated with hub genes such as CD74 and immune cells such as DCs, which are responsible for LCH. Since MARCKS is currently viewed as a potential target for immunotherapy and chemosensitivity, it is reasonable to believe that it will also be a potential therapeutic target for LCH [ 33 , 34 ].…”

MRCK-Alpha and Its Effector Myosin II Regulatory Light Chain Bind ABCB4 and Regulate Its Membrane Expression

“…More recently, Wenzel et al identified MARCKS, also as a key factor for the membrane expression of ABCB1. They showed that functional disruption of MARCKS led to an inhibition of ABCB1 internalization, resulting in its accumulation at the plasma membrane [ 36 ]. In another study, Chai et al showed that the activation of liver PKCs led to Ezrin Thr567 phosphorylation, resulting in ABCC2 internalization [ 37 ].…”