STK11

Overview

STK11 encodes serine/threonine kinase 11, also known as LKB1, a protein kinase with broad roles in cellular energy sensing, polarity, and growth control. It is a key upstream regulator of the AMPK pathway and related signaling networks, including downstream effects on mTOR-associated metabolism and stress responses. Because of these functions, STK11 is biologically important in maintaining normal cellular homeostasis and is frequently studied in cancer biology as a tumor suppressor-associated target.

In biomedical research, STK11 is especially relevant in contexts where altered metabolic signaling intersects with immune regulation and therapy response. Recent studies have examined STK11 in relation to checkpoint inhibitor, anti-PD-1 therapy, PD-L1-linked immune escape, and oncogenic KRAS-mutant disease, particularly non-small cell lung cancer and triple-negative breast cancer. These studies reinforce STK11’s role as a signaling node connecting metabolism, tumor proliferation, and antitumor immunity.

Focus of Latest Publications

Recent publications have investigated STK11 primarily as LKB1, focusing on its position upstream of AMPK and its influence on cancer cell survival, immune evasion, and treatment resistance.

One study on prexasertib reported that the drug’s cytotoxic effect results from dual inhibition of CHK1 and AMPK, and specifically noted increased AMPKα Thr172 phosphorylation via CAMKK2 and LKB1. In this context, STK11/LKB1 was implicated as part of the signaling axis controlling AMPK activation, highlighting its relevance to drug response and stress signaling.

Another study examined celastrol in triple-negative breast cancer (TNBC) and described suppression of immune escape and proliferation through the LKB1–AMPK–PD-L1/MYC signaling pathway. This places STK11 at the center of a pathway linking metabolic regulation to immune checkpoint-related mechanisms, including PD-L1 and MYC-associated tumor behavior.

In lung adenocarcinoma, a clinical study of first-line immunochemotherapy found that STK11 co-mutations were enriched among KRAS G12C, KRAS G12V, and other KRAS subtypes, and that these co-mutations correlated with shorter progression-free survival (PFS). This supports the clinical importance of STK11 status in KRAS-mutant disease and suggests that STK11 alterations may mark a subgroup with poorer outcomes under immunochemotherapy.

A separate study in ovarian cancer investigated SIK inhibitor therapy and found that human T cells exposed to patient ascites expressed high levels of SIK and the upstream kinase LKB1. The study reported that SIK inhibition reprogrammed human T cells and strongly activated antitumor responses, indicating that STK11/LKB1 participates in immune-cell signaling relevant to the tumor microenvironment and immunotherapy modulation.

Finally, a study on STK11 mutant NSCLC showed that tumors harboring STK11 mutations are resistant to standard-of-care anti-PD-1/PD-L1 blockade. The work further focused on CRTC2 as a target to reverse this resistance, underscoring the clinical significance of STK11 loss or mutation in immune checkpoint therapy failure and the search for downstream vulnerabilities.

Taken together, these studies position STK11 as a central regulator of metabolic signaling, immune escape, and therapeutic response across multiple cancer types. Its involvement in AMPK/mTOR, PD-L1-associated pathways, and KRAS-mutant tumors makes it a recurring target in translational oncology.

Key Publications

Jun The cytotoxic effect of prexasertib is a consequence of dual inhibition on both CHK1 and AMPK. (Cell chemical biology, 2026, PMID 42061410): "leading to increased AMPKα Thr172 phosphorylation via CAMKK2 and LKB1."
Jun Celastrol inhibits the immune escape and proliferation of triple - negative breast cancer (TNBC) through the LKB1 - AMPK - PD-L1/MYC signaling pathway. (International immunopharmacology, 2026, PMID 41966774): "This study explored the regulatory mechanisms related to celastrol in the treatment of TNBC and might provide potential therapeutic targets."
Jun Efficacy of first-line immunochemotherapy across KRAS mutation subtypes in advanced lung adenocarcinoma. (International journal of cancer, 2026, PMID 41634944): "STK11 co-mutations were enriched in G12C, G12V, and other subtypes (p=0.004) and correlated with shorter PFS (p=0.006)."
May Inhibition of salt-inducible kinases reprograms T cells and antitumor immunity in ovarian cancer. (Nature immunology, 2026, PMID 42162294): "Human T cells in the presence of patient ascites express high levels of SIK and the upstream kinase LKB1, whereas SIK inhibition reprograms human T cells and strongly activates antitumor responses."
Apr Targeting CRTC2 reverses STK11 mutant NSCLC tumor resistance to immunotherapy. (Proceedings of the National Academy of Sciences of the United States of America, 2026, PMID 42018410): "Non-small cell lung cancer (NSCLC) patients with tumors harboring STK11 mutations are resistant to standard of care anti-PD-1/PD-L1 blockade."