Among the crucial proteins having dual role in cancer and immunity is suppressor of cytokine-signaling3 (SOCS3) protein regulating JAK/STAT and IL 6/STAT3/NF-κB pathways, respectively. Another pivotal membrane anchoring protein; PIG-C, that anchors several proteins involved in carcinogenesis. Previous studies proved that miR-34a regulates PDL1. Also, our previous work proved that lncRNAs XIST and TSIX were able to manipulate PDL1 expression in triple negative breast cancer (TNBC). Therefore, this study aims at studying the impact of miR-34a, XIST/TSIX on SOCS3 and PIGC as novel targets to be added to the picture of molecular targeted immunotherapy.
Twenty pairs of BC tissues and adjacent non-BC tissues were collected from patients undergoing tumor resection surgery. MDA-MB-231 cell line was cultured, transfected for manipulation of gene expression purposes. Total RNA was extracted using Biozol followed by reverse transcription cDNA synthesis, amplification and quantification using quantitative-real-time PCR.
PIG-C was up-regulated in BC compared to controls (p = 0.0017). MiR-34a decreased PIG-C expression in BC cells lines (p < 0.0001) while anti-miR-34a increased PIG-C (p = 0.0259). MiR-34a increased SOCS3 (p = 0.0192) while anti-miR-34a decreased SOCS-3 (p = 0.0003). Upon XIST knockdown, PIG-C was up-regulated (p = 0.0243) and surprisingly SOCS3 was also up-regulated (p = 0.0092). Oppositely, siTSIX decreased PIG-C (p = 0.0320) and it significantly decreased SOCS3 (p = 0.0005) ensuring the previous results with siXIST. Co-transfection of miR-34a and siXIST decreased PIGC (p < 0.0001). Similarly, PIG-C decreased upon co-transfection of miR-34a and siTSIX (p < 0.0001). SOCS3 increased upon co-transfection of miR-34a with siTSIX (p = 0.0017). Synergistically, SOCS3 increased in the cells co-transfected with miR-34a and siXIST (p = 0.0201).
Here, PIG-C and SOCS3 are introduced as new immunotargets in TNBC. In the context of epigenetic regulation, the cross-talk between non-coding RNAs revealed miR-34a to have the lead over XIST and TSIX in regulating PIG-C and SOCS3. These data pave the road for establishing new proteins for molecular targeted immunotherapy along with their key upstream non-coding RNA regulators.
Clinical trial identification
Legal entity responsible for the study
German University in Cairo, Egypt.
Has not received any funding.
All authors have declared no conflicts of interest.