Vasculogenic mimicry (VM)‐positive melanomas are usually associated with poor prognosis. Rictor, the key component of the rapamycin‐insensitive complex of mTOR (mTORC2), is up‐regulated in several cancers, especially in melanomas with poor prognosis. The aim of this study was to investigate the role of Rictor in the regulation of VM and the mechanism underlying this possible regulation. VM channels were found in 35 of 81 tested melanoma samples and high Rictor expression correlated with VM structures. Moreover, Kaplan–Meier survival curves indicated that VM structures and high Rictor expression correlated with shorter survival in patients with melanoma. In vitro, Rictor knockdown by short hairpin RNA (shRNA) significantly inhibited the ability of A375 and MUM‐2B melanoma cells to form VM structures, as evidenced by most tubes remaining open. Cell cycle analysis revealed that Rictor knockdown blocked cell growth and resulted in the accumulation of cells in G2/M phase, and cell migration and invasion were greatly affected after Rictor down‐regulation. Western blotting assays indicated that down‐regulating Rictor significantly inhibited the phosphorylation of AKT at Ser473 and Thr308, which subsequently inhibited the expression and activity of downstream MMP‐2/9, as confirmed by real‐time PCR and gelatin Zymography. MK‐2206, a small‐molecule inhibitor of AKT, similarly inhibited the activity of AKT and secretion of MMP‐2/9, further supporting that Rictor down‐regulation inhibits the phosphorylation of AKT and activity of downstream MMP‐2/9 to affect VM formation. In conclusion, Rictor plays an important role in melanoma VM via the Rictor—AKT—MMP‐2/9 signalling pathway.

Background The third‐generation EGFR‐TKI, represented by osimertinib, has been widely used in clinical practice; however, resistance eventually emerges. At present, it remains unclear whether an abnormal cell cycle is involved in acquired resistance, and whether the combination of palbociclib (CDK4/6 inhibitor) and osimertinib can overcome the third‐generation TKI resistance. Methods We established osimertinib‐resistant cells (H1975 OR) derived from EGFR‐mutant NSCLC cells H1975. Drug effects on cells were assessed with Cell Counting Kit‐8 (CCK8). Protein alterations were detected with western blot analysis. RT‐PCR was used to evaluate the differences of gene mRNA. Cell cycle distribution of H1975 S and H1975 OR cells was compared using flow cytometry. Results Compared with H1975, the sensitivity of H1975OR to the CDK4/6 inhibitor was increased and the proportion of cells in G1 phase was decreased. The mRNA level of CDK4, CDK 6 and the protein level of CDK4, pRB were increased in H1975OR. In the H1975OR cells, palbociclib significantly increased the proportion of G1 phase cells. The combination of osimertinib and palbociclib synergistically decreased the survival of H1975OR by cell cycle arrest. Combined treatment was found to inhibit the initial phosphorylation of RB by inhibiting the function of CDK4/6, significantly reducing the level of p‐RB, and blocking cell proliferation. Conclusions An osimertinib acquired resistance cell line (H1975 OR) was successfully established. The expression of cell cycle related genes was altered in H1975OR. The expression of CDK4 and the phosphorylation of Rb, the downstream molecule of CDK4/6, was increased in H1975OR cells. The combination of CDK4/6 inhibitor palbociclib and osimertinib could overcome the acquired resistance of osimertinib.

Background: The resistance mechanism of the third generation of epidermal growth factor (EGFR) tyrosine kinase inhibitor (TKI) osimertinib is complex. Epithelial mesenchymal transition (EMT) is a common mechanism of EGFR-TKI acquired resistance. Snail is an important transcription factor related to EMT. Whether targeting Snail can reverse the resistance of osimertinib by downregulating Snail is unknown. Methods: The presence of EMT in H1975/OR (osimertinib resistance) cells was confirmed by transwell assay. To explore the EMT role in resistance, the expression levels of EMT markers were detected in both parental cells H1975 and resistant cells H1975OR. We used RNA interference technology to knockdown the key regulator Snail in resistant cells. After the interference efficiency was confirmed, changes in EMT-related molecules of Snail were explicitly downregulated, and changes in sensitivity and migration and invasion ability were also examined. We used CDK4/6 inhibitor to test the ability of reversing drug resistance by downregulating Snail. Results: Compared with the H1975 cell line, the H1975/OR resistant cell line showed increased invasiveness, upregulated expression of vimentin and downregulation of Ecadherin. EMT occurred in the H1975/OR resistant cell line. The expression of Snail was upregulated in the osimertinib-resistant cell line H1975/OR. Knockdown of Snail increased the sensitivity of H1975/OR cells to osimertinib. CDK4/6 inhibitor palbociclib could downregulate the expression of Snail. CDK 4/6 inhibitor palbociclib combined with osimertinib could reverse the resistance of osimertinib in H1975/OR. Conclusions: Snail plays an important role in the third generation of EGFR-TKI osimertinib resistance, which may be reversed by downregulating Snail.

Novel cyclodextrin derivative, glutamine-β-cyclodextrin, is developed as DOX carrier to minimize its side effects via TNBC tumors addiction to glutamine.

Background Lung adenocarcinoma (LUAD) is the most prevalent pathological subtype of lung cancer. Kinesin family member 18A (KIF18A) plays an important role in tumorigenesis. Its roles in breast cancer, colorectal cancer, and other tumors have been demonstrated; however, studies of KIF18A in LUAD are limited. This study aimed to determine the role of KIF18A in LUAD progression and prognostic prediction. Methods KIF18A expression was examined in LUAD cells and tissues by immunohistochemistry and Western blotting. Cell proliferation assay was performed to study the role of KIF18A in LUAD cells. Correlations between KIF18A expression and clinicopathological features were analyzed. The role of KIF18A in LUAD prognosis was evaluated using data from The Cancer Genome Atlas (TCGA). Results KIF18A expression was increased in tumor cells and tissues. Downregulation of KIF18A expression resulted in the suppression of cancer cell proliferation in in vitro assays, and was particularly related to poor tumor differentiation, big tumor size, lymph node metastasis, and more advanced tumor stage. In the TCGA dataset, high KIF18A messenger RNA expression was associated with poor disease‐free and overall survival in patients with LUAD. In addition, multivariate analysis indicated that KIF18A is an independent prognostic factor of disease‐free and overall survival in LUAD. Conclusions Collectively, our results demonstrate that KIFl8A is highly expressed in LUAD. KIFl8A plays an important role in LUAD cell proliferation, but is a poor prognostic factor.