PFKFB3 Inhibition Sensitizes DNA Crosslinking Chemotherapies by Suppressing Fanconi Anemia Repair

Abstract

Replicative repair of interstrand crosslinks (ICL) generated by platinum chemotherapeutics is orchestrated by the Fanconi anemia (FA) repair pathway to ensure resolution of stalled replication forks and the maintenance of genomic integrity. Here, we identify novel regulation of FA repair by the cancer-associated glycolytic enzyme PFKFB3 that has functional consequences for replication-associated ICL repair and cancer cell survival. Inhibition of PFKFB3 displays a cancer-specific synergy with platinum compounds in blocking cell viability and restores sensitivity in treatment-resistant models. Notably, the synergies are associated with DNA-damage-induced chromatin association of PFKFB3 upon cancer transformation, which further increases upon platinum resistance. FA pathway activation triggers the PFKFB3 assembly into nuclear foci in an ATR- and FANCM-dependent manner. Blocking PFKFB3 activity disrupts the assembly of key FA repair factors and consequently prevents fork restart. This results in an incapacity to replicate cells to progress through S-phase, an accumulation of DNA damage in replicating cells, and fork collapse. We further validate PFKFB3-dependent regulation of FA repair in ex vivo cultures from cancer patients. Collectively, targeting PFKFB3 opens up therapeutic possibilities to improve the efficacy of ICL-inducing cancer treatments.

Role of 6-Phosphofructo-2-Kinase/Fructose-2,6-Bisphosphatase-3 in Maintaining Redox Homeostasis and DNA Repair in Non-Small Cell Lung Cancers Under EGFR-Targeting Therapy

“…4A, B). Considering that elevated DNA oxidation can result from reduced DNA repair capacity and that PFKFB3 can directly affect DNA repair (9,30), we hypothesized that PFKFB3 is involved in the DNA damage response or repair in lung cancer cells insulted by ROS. Under standard conditions, oxidized nucleotides can be directly removed from DNA via the base-excision repair (BER) mechanism.…”

“…Our findings indicate that oxidative stress driven by PFKFB3 inhibition in TKI-treated cells promotes DNA oxidation, resulting in double-strand DNA damage. While the role of PFKFB3 in regulating DNA integrity through homologous recombination (30)and miss-match repair pathways is known (30) (9), we discovered that PFKFB3 also regulates base excision repair in TKI-treated cells. Specifically, we found that PFFKB3 sustains the expression of DNA-glycosylases such as MPG, NTHL1, and UNG1/2, which recognize and eliminate modified nucleotides.…”

“…It has been shown that the glycolytic enzyme 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB3) plays a crucial role in maintaining redox homeostasis (8) and regulating DNA damage repair (6,9). These findings led us to hypothesize that PFKFB3-driven metabolism limits the efficacy of EGFR-targeting therapies by alleviating oxidative stress and preserving DNA integrity.…”

Specific PFKFB3 Inhibitor Memorably Ameliorates Intervertebral Disc Degeneration via Inhibiting NF-κB and MAPK Signaling Pathway and Reprogramming of Energy Metabolism of Nucleus Pulposus Cells

“…Thus, therapies targeting an enhanced glycolytic caused IVD acidic environment are a new direction worthy to be exploited. KAN, an emerging selective inhibitor of key rate-limiting metabolic kinase PFKFB3, has been used to treat colorectal cancer and elevate the efficacy of interstrand crosslink- (ICL-) inducing cancer therapies due to the function during DNA damage [ 32 , 33 ]. However, research on the diseases principally influenced by its glycolysis regulation function is still blank.…”

Focal Point of Fanconi Anemia Signaling

“…To date, numerous targets derived from either upstream or downstream of DDR/FA signaling are under testing to increase the sensitivity of chemotherapy [ 2 , 102 , 103 , 104 ]. Many of them may be promising initially; but nearly all would eventually develop resistance.…”