Intracellular Acidosis Promotes Mitochondrial Apoptosis Pathway: Role of EMMPRIN Down-regulation via Specific Single-chain Fv Intrabody

Abstract

Extracellular matrix metalloproteinase inducer (EMMPRIN) is a human leukocyte surface molecule that is enriched on the surface of many cancer cells, and it plays an important role in proliferation and metastasis. In this study, we utilized the chimeric adenoviral vector Ad5/F35 carrying gene encoding scFv against EMMPRIN (scFv-M6-1B9) to down-regulate EMMPRIN cell surface expression and investigated programmed cell death response in colorectal cancer (CRC) cell, Caco-2. The scFv-M6-1B9 intrabody exhibits robust activity in reducing EMMPRIN cell surface expression. This approach led to the inducing of apoptosis, which was relative to the increasing of apoptotic bodies in sub-G1 peak, phosphatidylserine externalization, as well as TUNEL-positive cells. In addition, real-time RT-PCR and western blotting analysis indicated that apoptosis was enhanced through the mitochondrial pathway, a marked reduction of Bcl-2, leading to the translocation of cytochrome c and also the dramatic activation of caspase-3. Moreover, carcinoembryonic antigen (CEA), a tumor marker for CRC, was found to have significantly diminished in both secreted protein and mRNA levels. In conclusion, these findings suggest that EMMPRIN down-regulation by scFv-M6-1B9 intrabody has great potential in enhancing the efficacy of apoptosis induction through the mitochondrial pathway and in effecting a decline in the CEA level. Thus, its benefits could be applied to project the future prospects for targeted gene therapy and therapeutic application in monitoring colorectal cancer.

Icaritin inhibits the invasion and epithelial‐to‐mesenchymal transition of glioblastoma cells by targeting EMMPRIN via PTEN/AKt/HIF‐1α signalling

“…Interestingly, inhibition of EMMPRIN via RNA interference has been found to induce apoptosis in both solid tumour cells and haematologically malignant cells. 41,45,46 Additionally, a role of EMMPRIN in autophagic cell death has been reported. 47,48 Therefore, by downregulating EMMPRIN, icaritin might exert an anti-tumour effect by targeting multiple steps in tumour progression, including promoting apoptosis, inducing autophagy and suppressing invasion and metastasis.…”

“…Consistent with these previous studies, evidence from the present study also showed that icaritin suppressed the invasive potential of GBM cells by downregulating EMMPRIN expression, supporting the role of EMMPRIN as novel target for suppressing GBM invasion. Interestingly, inhibition of EMMPRIN via RNA interference has been found to induce apoptosis in both solid tumour cells and haematologically malignant cells . Additionally, a role of EMMPRIN in autophagic cell death has been reported .…”

Combination of lactate calcium salt with 5-indanesulfonamide and α-cyano-4-hydroxycinnamic acid to enhance the antitumor effect on HCT116 cells via intracellular acidification

“…Apoptotic stimuli, including cancer chemotherapies, are capable of inducing intracellular acidification (29). Direct induction of an acidic pHi reportedly triggers the classic hallmarks of apoptosis, including nuclear condensation, cytoplasmic vacuolization and endonuclease-mediated DNA degradation (30). These observations suggest a direct association between acidification and a decrease in the viability of colon cancer cells.…”

Applying Antibodies Inside Cells: Principles and Recent Advances in Neurobiology, Virology and Oncology

“…The retention of a particular integrin subunit in the ER by an intrabody allowed study of how integrin heterodimers form and revealed a hierarchy in complex formation when different subunits combine [280]. Tumour invasion and metastasis were further targeted using an intrabody to block the activation of matrix metalloproteinases in an in vitro model [281,282]. Plasma membrane extensions that also have proteolytic activity, called invadopodia, allow cancer cells to invade their surroundings and form metastases.…”