CCT6A functions as promising diagnostic biomarker and promotes cell proliferation in colorectal cancer.

Background: Chaperonin-containing tailless complex polypeptide 1 subunit 6A (CCT6A) is mainly located in the cytoplasm and considered to be involved in various biological processes in tumors. However, its function and the intrinsic mechanism need to be further elucidated. Methods: Multi-omics analysis was used to evaluate the correlation between CCT6A expression and prognosis of patients, as well as its immune value. CCT6A was knockout by CRISPR-Cas9, and overexpressed by transfecting plasmids in colorectal cancer (CRC) cells. Cell proliferation was analyzed by MTS, EDU staining and colony growth assay, and cell migration was monitored by wound healing assay and Transwell assay. The phosphor-kinase array kit and immunoblotting assay was utilized to explore the potential molecular mechanisms. Results: CCT6A was highly expressed in multiple tumor tissues and significantly correlated with the prognosis of patients. It was also associated with the immune infiltration, immune correlation and prognosis in CRC. CCT6A was highly expressed in CRC biopsies as well as fresh CRC tissues. Meanwhile, knockout of CCT6A reduced cell proliferation, cell cycle and cell migration. On the contrary, overexpression of CCT6A exhibited the opposite phenotypes. Moreover, we identified that HSPD1 and non-phosphorylated P53 were highly increased in CCT6A overexpressed cells, which are involved in regulating tumorigenesis. Conclusions: Therefore, CCT6A positively regulated cell proliferation/migration in CRC cells, and suggesting CCT6A has a high immunological value and is associated with CRC progression, which makes it a potential therapeutic target for CRC.

PFKFB3 deprivation attenuates the cisplatin resistance via blocking its autophagic elimination in colorectal cancer cells.

Introduction: 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase isoform 3 (PFKFB3) is highly expressed in several cancers and plays important roles during the whole pathological process of cancer. It is also involved in chemoresistance, while the intrinsic mechanism needs to be further revealed. Methods: The different responses to cisplatin (DDP) between wild type (WT) and DDP-resistant (DDR) colorectal cancer (CRC) cells were analyzed by several assays. Coumarin conjugated DDP (CP-DDP) was utilized to trace the distribution of DDP. Pharmacological and genetic methods were used to deprive autophagy and PFKFB3, and the effects were investigated. The mouse xenograft model was performed to confirm the effect of the PFKFB3 inhibitor on reversing DDP resistance. Results: DDR cells showed a lower capacity for apoptosis upon DDP treatment, but exhibited higher levels of autophagy and PFKFB3. CP-DDP partly co-localized with LC3, and its content lessened faster in DDR cells. Deprivation of both autophagy and PFKFB3 attenuated CP-DDP elimination, and reversed the DDP resistance. Moreover, PFKFB3 inhibition reduced DDP-induced autophagy. PFKFB3 inhibitor in combination with DDP led to a remarkable reduction in tumor growth in vivo. Discussions: Inhibition of PFKFB3 reduced the autophagy induced by DDP, and therefore extended the retention time of CP-DDP. Meanwhile, PFKFB3 deprivation reversed the DDP resistance and made it a potent therapeutic target for CRC.

GNL3L promotes autophagy via regulating AMPK signaling in esophageal cancer cells.

Guanine nucleotide-binding protein-like 3-like (GNL3L), a conserved GTP-binding nucleolar protein, participates in regulating cell proliferation, and associates with tumorigenesis and poor prognosis in several kind of cancers. However, the role of GNL3L in modulating autophagy remains unclear. Here, we verified that GNL3L was higher expressed in esophageal cancer (ESCA) biopsies than that in the corresponding normal biopsies by a human ESCA tissue array. Utilizing immunoblotting and real-time PCR assays, we analyzed the expression of GNL3L in several ESCA cell lines, and it was highly expressed in KYSE410 cells and rarely expressed in KYSE150 cells, respectively. GNL3L overexpression promoted cell viability and cell proliferation in KYSE150 cells. On the contrary, silencing of GNL3L resulted in opposite phenotypes in KYSE410 cells. Furthermore, GNL3L level correlated with autophagic flux and influenced the levels of autophagy core proteins. Meanwhile, GNL3L also affected the AMPK signaling pathway, which is a pivotal signaling pathway for autophagy regulation. In the GNL3L-silenced cells, the AMPK agonist AICAR partly rescued the autophagic flux. Inversely, both pharmacologically and genetically deprivation of AMPK attenuated the autophagic flux induced by GNL3L overexpression. Moreover, AMPK activity alteration influenced the effect of GNL3L in regulating cell proliferation. Collectively, these findings suggest that GNL3L positively regulates cell proliferation and autophagy in ESCA cells via regulating the AMPK signaling, making itself a promising therapeutic target for ESCA.