A gene signature for immune subtyping of desert, excluded, and inflamed ovarian tumors

PROBLEM

The current tumor immunology paradigm emphasizes the role of the immune tumor microenvironment and distinguishes several histologically and transcriptionally different immune tumor subtypes. However, the experimental validation of such classification is so far limited to selected cancer types. Here, we aimed to explore the existence of inflamed, excluded, and desert immune subtypes in ovarian cancer, as well as investigate their association with the disease outcome.

METHOD OF STUDY

We used the publicly available ovarian cancer dataset from The Cancer Genome Atlas for developing subtype assignment algorithm, which was next verified in a cohort of 32 real-world patients of a known tumor subtype.

RESULTS

Using clinical and gene expression data of 489 ovarian cancer patients in the publicly available dataset, we identified three transcriptionally distinct clusters, representing inflamed, excluded, and desert subtypes. We developed a two-step subtyping algorithm with COL5A2 serving as a marker for separating excluded tumors, and CD2, TAP1, and ICOS for distinguishing between inflamed and desert tumors. The accuracy of gene expression-based subtyping algorithm in a real-world cohort was 75%. Additionally, we confirmed that patients bearing inflamed tumors are more likely to survive longer.

CONCLUSION

Our results highlight the presence of transcriptionally and histologically distinct immune subtypes among ovarian tumors and emphasize the potential benefit of immune subtyping as a clinical tool for treatment tailoring.

Salinomycin and dichloroacetate synergistically inhibit Lewis lung carcinoma cell proliferation, tumor growth and metastasis

Drug combination is considered to be the cornerstone of cancer treatment. Simultaneous administration of two or more drugs but at lower doses not only increases cytotoxic effects on tumor cells, but also reduces side effects and possibly overcomes drug resistance. Salinomycin is a well-known cancer stem cell killer, and dichloroacetate is a pyruvate dehydrogenase kinase inhibitor that exclusively targets cells with altered mitochondrial activity, a characteristic being common to most of the cancer cells. In our recent study, we have demonstrated that salinomycin exerted a cytotoxic effect on colorectal carcinoma cells in the 2D and 3D cultures and provided evidence that the mechanism of their synergy was mediated by dichloroacetate-dependent inhibition of the activity of multidrug resistance proteins. In the current work, we confirmed the synergistic cytotoxic properties of salinomycin and dichloroacetate in the 2D and 3D cultures of Lewis lung carcinoma (LLC1) cells. To verify if a synergistic effect of these compounds persisted in vivo, we performed series of experiments using a syngeneic LLC1-C57BL/6 mouse model and demonstrated that combination therapy with salinomycin and DCA increased the survival rate of allografted mice, inhibited metastatic site formation and reduced the populations of cancer stem cells as well as cells that underwent the epithelial-to-mesenchymal transition. Our results demonstrate that a synergistic effect of salinomycin and dichloroacetate exists not only in vitro but also in vivo and suggest their benefits in the treatment of metastatic cancers.

Expression of cytokeratin 7 as a histological marker of cholestasis and stages of primary biliary cirrhosis

The aim of this study was to estimate cytokeratin 7 (CK-7) expression in biopsy specimens of patients with different stages of primary biliary cirrhosis and clinicopathological patterns (cholestatic and hepatitic) and its correlation with some biochemical and pathological parameters and to examine a diagnostic value of CK-7 expression.

MATERIAL AND METHODS

A total of 82 biopsy specimens of patients with primary biliary cirrhosis were analyzed. CK-7 expression was graded by 4 grades depending on the extent into parenchymal areas and bile duct epithelium. The correlations of CK-7 expression grade with copper deposition, bile duct/portal tract ratio, bilirubin concentration, and activity of alkaline phosphatase and gamma-glutamyl transpeptidase were studied. CK-7 expression was evaluated as a marker of cholestasis (cholestatic pattern) and inflammation (hepatitic pattern).

RESULTS

A positive correlation of CK-7 expression grade with copper-binding protein grade (r=0.698, P<0.0001; OR=6.199, P<0.0001), serum bilirubin level (r=0.375, P=0.001), and alkaline phosphatase activity (r=0.276, p=0.014) was found. CK-7 expression grades correlated positively with histological stages of primary biliary cirrhosis (r=0.639, P<0.000) and negatively with granulomas (r=-0.432, P<0.0001; OR=0.173, P=0.0011).

CONCLUSIONS

CK-7 expression is a sensitive marker of bile duct injury, which correlated well with histological stages of primary biliary cirrhosis, copper deposits, and biochemical markers of cholestasis: serum bilirubin level and alkaline phosphatase activity. Evaluation of CK-7 expression may improve the diagnosis of this serious and progressive disease. It is recommended to evaluate copper staining together with cytokeratin 7 expression in liver biopsy specimens for more precise diagnostic evaluation of asymptomatic primary biliary cirrhosis.