Epithelial cancer has been modeled in flies using the Drosophila Lkb1 gene in combination with an activated mutation of the Drosophila Ras85D gene (Ras85DV12). Dmel\Lkb1 is orthologous to the human STK11 gene, which encodes a serine/threonine-protein kinase known to function as a tumor suppressor. High levels of oncogenic RAS expression and loss of STK11 has been observed in aggressive human lung adenocarcinomas. See the human disease model report 'cancer, multiple, RAS-related' (FBhh0000474) for more information on RAS genes in human.
Constructs representing different isoforms of the human Hsap\STK11 gene have been introduced into flies, but have not been characterized in the context of this disease model. Of the human RAS genes (KRAS, HRAS, NRAS), Hsap\HRAS has been introduced into flies, but has not been characterized.
Using an assay in Drosophila in which clones are induced in the developing eye, it has been shown that relative levels of activated Ras85D determine clonal growth dynamics in Lkb1 loss-of-function mutant tissue. Clones expressing low levels of activated Ras85D result in reduced-eye phenotypes; clones expressing Lkb1 loss-of-function mutants result in a rough-eye phenotype; the combination results in significant overgrowth of eye tissue, producing a folded eye phenotype. High levels of activated Ras85D combined with Lkb1 loss-of-function mutants promotes malignant progression and organismal lethality; these animals usually die in the larval stage. The role of the AMPK pathway has been investigated in this system.
[updated Feb. 2021 by FlyBase; FBrf0222196]
LKB1 activity is lost in a wide spectrum of human cancers; the gene that encodes LKB1 (STK11) is the third most frequently mutated tumor suppressor in human lung adenocarcinoma. KRAS is the most commonly mutated oncogene in human cancer, and is frequently mutated in cancer types associated with high mortality such as non-small cell lung cancer. Large-scale sequencing of lung adenocarcinoma has uncovered heterogeneity in mutant KRAS tumors due to concomitantly mutated tumor suppressor genes such as STK11 (FBrf0247944 and references cited therein).
STK11 encodes serine/threonine-protein kinase that controls the activity of AMP-activated protein kinase (AMPK) family members, thereby playing a role in various processes such as cell metabolism, cell polarity, apoptosis and DNA damage response; functions as a tumor suppressor. [from Gene Cards, STK11; 2021.02.17]
One to one: 1 human gene to 1 Drosophila gene.
High-scoring ortholog of human STK11 (1 Drosophila to 1 human). Dmel\Lkb1 shares 53% identity and 69% similarity with the human gene.