LINC00337 induces tumor development and chemoresistance to paclitaxel of breast cancer by recruiting M2 tumor-associated macrophages

Background: M2 tumor-associated macrophages are closely related to the progression and prognosis of breast Cancer (BCa), and could be regulated by long intergenic non-coding RNAs (lincRNAs). Moreover, the differential expression of lincRNAs affects tumor resistance. This study focused on the potential involvement and mechanism of LINC00337 in BCa.

Methods: The expression of LINC00337 in BCa was detected by bioinformatics analysis and RT-qPCR. Cell viability and proliferation were analyzed by cell counting kit-8 (CCK-8) and clone formation assay. BCa cells were treated with different concentrations of paclitaxel (PAX) to determine the chemotherapy resistance of LINC00337. Tumor formation assay, Western blot, ELISA and immunohistochemistry were performed to determine the relationship between LINC00337 and PAX in vivo. Macrophages were induced to M2-like polarization, and then functional experiments (CCK-8, wound healing) and molecular experiments (ELISA, RT-qPCR, Western blot) were used to verify the role of LINC00337.

Results: LINC00337 was up-regulated in BCa. High-expressed LINC00337 accelerated viability and proliferation of BCa cells, improved the resistance of BCa cells to PAX, and accelerated tumor growth. Overexpressed LINC00337 up-regulated the expressions of M2 macrophage markers and M-CSF, and reduced the level of GM-CSF. PAX significantly reduced the viability of BCa cells and down-regulated LINC00337. Furthermore, the successfully induced M2 type macrophages to promote BCa cell activity, migration and EMT protein expression, and LINC00337 enhanced the effect of M2 type macrophages. ShLINC00337 had the opposite effect to overexpressed LINC00337.

Conclusion: LINC00337 accelerated the malignant phenotype of BCa cells and promoted chemoresistance to paclitaxel through M2-like macrophages.