PLK4 expression

Increased PLK4 levels in cells with C-Nap1 and Rootletin knock-out resulted with distanced CRs and CRCs in interphase, while Nek2 knock-out inhibited separation of CRCs in prometaphase, providing functional evidence for the binding of CRC structures with centrosomal linker proteins. Taken together, these results suggest a cell cycle dependent model for PLK4 induced centrosome amplification which occurs in 2 consecutive cell cycles: (i) CR state in the first cell cycle, and (ii) CRC state in the second cell cycle.

In our previous studies, we showed that inhibition of Polo-like Kinase 4 (PLK4) by a novel drug, CFI-400945 significantly enhances the anticancer effects of radiotherapy (RT) compared to single treatment alone...Our data suggest that PLK4 is a promising target for enhancing the anticancer effects of RT in TNBC that, at least in part, is modulated by the overamplification of centrioles. These results support further mechanistic and translational studies of anti-PLK4 agents and RT as an anticancer combination treatment strategy.

Additionally, the expression of PLK4 protein exhibited a positive correlation with AKT1 phosphorylation in glioma patient tissues. These findings highlight the pivotal role of PLK4-mediated phosphorylation of AKT1 in glioma tumorigenesis and dysregulation of glucose metabolism.

As such, numerous small-molecule inhibitors with distinct chemical scaffolds targeting PLK4 have been extensively investigated for the treatment of different human cancers, with several undergoing clinical evaluation (e.g., CFI-400945). Here, we review the structure, distribution, and biological functions of PLK4, encapsulate its intricate regulatory mechanisms of expression, and highlighting its multifaceted roles in cancer development and metastasis. Moreover, the recent advancements of PLK4 inhibitors in patent or literature are summarized, and their therapeutic potential as monotherapies or combination therapies with other anticancer agents are also discussed.

In vivo, PLK4 inhibition also induced cytokine and chemokine expression in mouse recipients and its combination with anti-CD47 antibody, which inhibited the "don't-eat-me" signal in macrophages, synergistically reduced leukemic burden and prolonged animal survival. The study shed important light on the pathogenetic role of PLK4 and might lead to novel therapeutic strategies in TP53 mutated AML.

ConclusionOur data indicate that HDAC inhibitor Chidamide significantly synergizes GL-V9-induced cell growth inhibition, apoptosis, and cell cycle arrest in AML, and the underlying mechanism by suppressing the expression of ESPL1 and PLK4, the key regulators of cell division and proliferation. Our results also provide a potential chemotherapy-free option for AML patients.

Background: CFI-400945 is a potent, selective, orally administered, first-in-class inhibitor of the serine/threonine kinase Polo-like kinase 4 (PLK4), a unique Polo-like kinase family member, that is a conserved upstream regulator of centriole duplication. CFI-400945 has been generally well tolerated in this difficult to treat patient population, including patients whose disease progressed on or following venetoclax based therapies. Three of 6 evaluable patients with AML achieved a response (MLFS=2, CRi=1) at the 96mg dose. PK characteristics support daily dosing of CFI-400945 and PD studies are ongoing.

PLK4 expression and pathways that were highly correlated with PLK4 expression levels were upregulated in patients with LUAD with the TP53 mutation. (4) PLK4 expression affects the survival of patients with LUAD and is a potential therapeutic target for LUAD with TP53 mutations.

Our findings reveal that downregulation of PLK4-induced autophagy contributes to tumor dormancy and autophagy inhibition leads to apoptosis of CRC dormant cells. Our study is the first to report that downregulation PLK4 induced autophagy is an early event in CRC dormancy and highlights autophagy inhibitor as a potential therapeutic target for dormant cell elimination.

And in intracranial tumor mouse models, PLK4 inhibition increased tumor-infiltrating M1 macrophages. In summary, our results demonstrated the correlation between high PLK4 expression level and malignant progression of gliomas, and the possible involvement of PLK4 in regulation of cell cycle, cell proliferation and macrophages infiltration in gliomas.

Also, the drug-like properties prediction of compound WY29 displayed remarkable drug-like properties (drug-likeness mode score: 1.06). In conclusion, these results support the further development of compound WY29 as a lead compound for PLK4-targeted anticancer drug discovery.

CFI-400945 has been generally well tolerated and TWT-202 continues to enroll in Part 1. There have been no responses per ELN to date but there was SD in 2 pts (48 mg dose). Lack of DLTs suggest dose level is still suboptimal at time of submission.

For the precise therapy of breast cancers, PLK1 and PLK4 are potential targets, while PLK2, PLK3, and PLK5 are brand-new biomarkers for predicting the prognosis of breast cancer.

Our data suggest that the PLK4 expression is closely related to the level of immune infiltration and the cytokines that exert immune suppression, and IPS was significantly higher in the PLK4 low expression group. The PLK4 expression is associated with the prognosis of ccRCC patients and affects the immune microenvironment of ccRCC, and PLK4 is expected to be a new target for the diagnosis and treatment of ccRCC.

Consistent with above results, knockdown the expression of PLK4 also inhibited cell proliferation and colony formation, induced cell apoptosis, and caused G2/M phase cell cycle arrest without affecting cell differentiation. All in all, this study suggested that PLK4 inhibited the progression of AML in vitro, and these results herein may provide clues in roles of PLK4 in the leukemiagenesis of AML.

Besides, PLK4 at diagnosis was positively linked with the Chinese Medical Association risk stratification (P=0.016), but not with prednisone response (P=0.077) or bone marrow response (P=0.083)...In terms of prognosis, high PLK4 was associated with shorter event-free survival (P=0.020), whereas it was not related to the overall survival (P=0.135). In conclusion, PLK4 has the potential as a biomarker for treatment response and prognostic risk stratification of childhood ALL patients.

In addition, PLK4-small interfering RNA (siRNA) was transfected into CRC cells, followed by 5-fluorouracil (5-FU) treatment for it was a fundamental chemotherapy for CRC...In conclusion, the high expression of tumor PLK4 was associated with advanced TNM stage and shorter OS in patients with CRC. In addition, targeting PLK4 improved chemosensitivity in CRC cells.

CA is prevalent in PCa and arises predominantly by centriole overduplication as opposed to cell doubling events. Loss of centrioles is cellular stress that can promote senescence and suggests that PLK4 inhibition may be a viable therapeutic strategy in PCa.

Finally, PLK4 overexpression significantly reversed all the effects of Fraxetin on DU145 cells. Collectively, Fraxetin acted as a cancer suppressor in prostate cancer through inhibiting PLK4 expression thereby inactivating PI3K/Akt signaling.

Further investigation by transcriptome sequencing indicated that PLK4 promotes the phosphorylation of focal adhesion kinase to regulate the focal adhesion pathway in HCC cell migration. Taken together, our results demonstrated that PLK4 plays an important role in HCC metastasis and revealed for the first time the mechanism by which PLK4 promotes HCC metastasis via TEC phosphorylation.

These findings suggest that HIF-1α induces CA by directly upregulating PLK4 and could help us risk-stratify patients and design new therapies for CA-rich cancers. Implications: Hypoxia drives CA in cancer cells by regulating expression of PLK4, uncovering a novel HIF-1α/ PLK4 axis.

As of June 21, 2021, 2 patients had been enrolled into the study, one of the patients (50%) received >3 prior therapies (including venetoclax). CFI-400945 has been generally well tolerated and TWT-202 continues to enroll in the Part 1A and Part 1B monotherapy cohorts. Updated safety, efficacy, PK, and PD data for the study will be presented at the time of the meeting.

This study revealed an association between high expression of PLK4 in the pre-CRT specimens and TRG. Our results indicated that PLK4 could potentially be a new predictor for CRT effect in patients with rectal cancer.

While numerous novel treatment regimens, including the combination of the BCL2 inhibitor venetoclax (VEN) and hypomethylating agents (HMA), have emerged as partially effective treatments and resulted in higher remission rates in patients with TP53 -mutant AML, full clearance of the mutant TP53 clone is rarely achieved and the majority of patients relapse (Short et al., 2021; Takahashi et al., 2016). Our data suggest that TP53 -mutant AML expresses higher levels of PLK4 in comparison to TP53 -wt AML, and targeting PLK4 triggers polyploidy and apoptotic cell death in TP53 -mutant AML. A clinical trial is ongoing testing the efficacy of PLK4 inhibition (CFI-400945) in AML (Clinical Trial ID: NCT04730258, TWT-202).

TRIM37 expression correlated with response to Cisplatin, Paclitaxel, and Tamoxifen in breast cancer cell line study (r=0.655, r=0.446, and r=0.9, respectively). Taken together, TRIM37 high expression was associated with cell proliferation regardless of subtypes, but TRIM37 low expression was associated with high tumor infiltrating lymphocytes and immune response that may have contributed to the survival difference in ER-positive/HER2-negative patients, but not in TNBC. Conclusions : In conclusion, TRIM37 expression is associated with cell proliferation and DNA repair, less tumor infiltrating lymphocytes and immune response, and with worse survival in ER-positive/HER2-negative breast cancer.

High levels of PLK4 expression were associated with poor survival in the patients receiving CHOP-based treatment, implicating PLK4 as a predictive biomarker of DLBCL chemosensitivity. These results provide the therapeutic potential of CFI-400945 both as monotherapy or in combination with doxorubicin for the treatment of DLBCL.

Actinomycin D assay and RNase R digestion assay were conducted to analyze the feature of circKIF2A...Additionally, circKIF2A knockdown hampered tumorigenesis in vivo. CircKIF2A knockdown suppressed cell proliferation, migration, invasion and glycolysis via downregulating PLK4 expression through miR-129-5p.

Conclusion Based on our human tissue study results, PLK4 expression can be suggested as a potential prognostic factor and predictor of preoperative radiotherapy resistance. Therefore, clinical development of PLK4 could be an effective therapeutic strategy for radioresistant locally advanced rectal cancer.

Conclusion Based on our human tissue study results, PLK4 expression can be suggested as a potential prognostic factor and predictor of preoperative radiotherapy resistance. Therefore, clinical development of PLK4 could be an effective therapeutic strategy for radioresistant locally advanced rectal cancer.

Conclusion Based on our human tissue study results, PLK4 expression can be suggested as a potential prognostic factor and predictor of preoperative radiotherapy resistance. Therefore, clinical development of PLK4 could be an effective therapeutic strategy for radioresistant locally advanced rectal cancer.

The safety endpoint is the incidence of treatment emergent adverse events. PK endpoints include evaluations of parameters such as half-life, AUC, etc. Exploratory endpoints include eval of minimal residual disease, genomic alterations and other molecular features associated with response and biological effects of PLK4 inhibition.

Furthermore, the suppressive effect of miR-513c-5p overexpression on NB cell malignant progression in vitro was reversed by PLK4 upregulation. Our findings identified a novel regulatory mechanism, the DLX6-AS1/miR-513c-5p/PLK4 axis, in NB progression, highlighting a strong rationale for developing DLX6-AS1 as a new target for NB management.

Taken together, our study demonstrated that PLK4 is a susceptibility gene and plays an oncogenic role in HCC. Furthermore, we identified that PLK4 sensitives HCC to CFI-400945, which may be an ideal therapy target for HCC.

Finally, the animal experiment results further demonstrated that miR-654-3p inhibits tumour growth and regulates PLK4 expression. Our results demonstrate that miR-654-3p functions as a growth-suppressing miRNA by targeting PLK4 in NSCLC.