CDK12 promotes papillary thyroid cancer progression through regulating the c-myc/β-catenin pathway

Discovery and design of molecular glue enhancers of CDK12-DDB1 interactions for targeted degradation of cyclin K

The CDK12 inhibitor SR-4835 promotes the proteasomal degradation of cyclin K, contingent on the presence of CDK12 and the CUL4-RBX1-DDB1 E3 ligase complex. The inhibitor displays molecular glue activity, which correlates with its enhanced ability to inhibit cell growth. This effect is achieved by facilitating the formation of a ternary complex that requires the small molecule SR-4835, CDK12, and the adaptor protein DDB1, leading to the subsequent ubiquitination and degradation of cyclin K. We have successfully solved the structure of the ternary complex, enabling the de novo design of molecular glues that transform four different CDK12 scaffold inhibitors, including the clinical pan-CDK inhibitor dinaciclib, into cyclin K degraders. These results not only deepen our understanding of CDK12's role in cell regulation but also underscore significant progress in designing molecular glues for targeted protein degradation in cancers associated with dysregulated cyclin K activity.

CDK12 is a promising therapeutic target for the transcription cycle and DNA damage response in metastatic osteosarcoma

Osteosarcoma (OS) is a bone malignant tumor affecting children, adolescents, and young adults. Currently, osteosarcoma is treated with chemotherapy regimens established over 40 years ago. The investigation of novel therapeutic strategies for the treatment of osteosarcoma remains an important clinical need. Cyclin-dependent kinases (CDKs) have been considered promising molecular targets in cancer therapy. Among these, CDK12 has been shown to play a crucial role in the pathogenesis of malignancies, but its clinical significance and biological mechanisms in osteosarcoma remain unclear. In the present study, we aim to determine the expression and function of CDK12 and evaluate its prognostic and therapeutic value in metastatic osteosarcoma. We found that overexpression of CDK12 was associated with high tumor grade, tumor progression and reduced patient survival. The underlying mechanism revealed that knockdown of CDK12 expression with small interfering RNA or functional inhibition with the CDK12-targeting agent THZ531 effectively exhibited time- and dose-dependent cytotoxicity. Downregulation of CDK12 paused transcription by reducing RNAP II phosphorylation, interfered with DNA damage repair with increased γH2AX, and decreased cell proliferation through the PI3K-AKT pathway. This was accompanied by the promotion of apoptosis, as evidenced by enhanced Bax expression and reduced Bcl-xL expression. Furthermore, the CDK12 selective inhibitor THZ531 also hindered ex vivo 3D spheroid formation, growth of in vitro 2D cell colony, and prevented cell mobility. Our findings highlight the clinical importance of CDK12 as a potentially valuable prognostic biomarker and therapeutic target in metastatic osteosarcoma.

CircNRCAM up-regulates NRCAM to promote papillary thyroid carcinoma progression

PURPOSE

Papillary Thyroid Carcinoma (PTC) is the most prevalent subtype of Thyroid Carcinoma (THCA), a type of malignancy in the endocrine system. According to prior studies, Neural Cell Adhesion Molecule (NRCAM) has been found to be up-regulated in PTC and stimulates the proliferation and migration of PTC cells. However, the specific mechanism of NRCAM in PTC cells is not yet fully understood. Consequently, this study aimed to investigate the underlying mechanism of NRCAM in PTC cells, the findings of which could provide new insights for the development of potential treatment targets for PTC.

METHODS AND RESULTS

Bioinformatics tools were utilized and a series of experiments were conducted, including Western blot, colony formation, and dual-luciferase reporter assays. The data collected indicated that NRCAM was overexpressed in THCA tissues and PTC cells. Circular RNA NRCAM (circNRCAM) was found to be highly expressed in PTC cells and to positively regulate NRCAM expression. Through loss-of-function assays, both circNRCAM and NRCAM were shown to promote the proliferation, invasion, and migration of PTC cells. Mechanistically, this study confirmed that precursor microRNA-506 (pre-miR-506) could bind with m6A demethylase AlkB Homolog 5 (ALKBH5), leading to its m6A demethylation. It was also discovered that circNRCAM could competitively bind to ALKBH5, which restrained miR-506-3p expression and promoted NRCAM expression.

CONCLUSION

In summary, circNRCAM could up-regulate NRCAM by down-regulating miR-506-3p, thereby enhancing the biological behaviors of PTC cells.

CDK12 inhibition upregulates ATG7 triggering autophagy via AKT/FOXO3 pathway and enhances anti-PD-1 efficacy in colorectal cancer

As the world's fourth most deadly cancer, colorectal cancer (CRC) still needed the novel therapeutic drugs and target urgently. Although cyclin-dependent kinase 12 (CDK12) has been shown to be implicated in the malignancy of several types of cancer, its functional role and mechanism in CRC remain largely unknown. Here, we found that suppression of CDK12 inhibited tumor growth in CRC by inducing apoptosis. And CDK12 inhibition triggered autophagy by upregulating autophagy related gene 7 (ATG7) expression. Inhibition of autophagy by ATG7 knockdown and chloroquine (CQ) further decreased cell viability induced by CDK12 inhibition. Further mechanism exploration showed that CDK12 interacted with protein kinase B (AKT) regulated autophagy via AKT/forkhead box O3 (AKT/FOXO3) pathway. FOXO3 transcriptionally upregulated ATG7 expression and autophagy when CDK12 inhibition in CRC. Level of CDK12 and p-FOXO3/FOXO3 ratio were correlated with survival in CRC patients. Moreover, CDK12 inhibition improved the efficacy of anti-programmed cell death 1(PD-1) therapy in CRC murine models by enhancing CD8 + T cells infiltration. Thus, our study founded that CDK12 inhibition upregulates ATG7 triggering autophagy via AKT/FOXO3 pathway and enhances anti-PD-1 efficacy in CRC. We revealed the roles of CDK12/FOXO3/ATG7 in regulating CRC progression, suggesting potential biomarkers and therapeutic target for CRC.

CDK12 regulates angiogenesis of advanced prostate cancer by IGFBP3

Prostate cancer (PCa) is a prevalent malignancy among men, with a majority of patients presenting with distant metastases at the time of initial diagnosis. These patients are at a heightened risk of developing more aggressive castration‑resistant PCa following androgen deprivation therapy, which poses a greater challenge for treatment. Notably, the inhibition of tumor angiogenesis should not be considered an ineffective treatment strategy. The regulatory role of CDK12 in transcriptional and post‑transcriptional processes is essential for the proper functioning of various cellular processes. In the present study, the expression of CDK12 was first knocked down in cells using CRISPR or siRNA technology. Subsequently, RNA‑seq analysis, co‑immunoprecipitation, western blotting, reverse transcription‑quantitative polymerase chain reaction and the LinkedOmics database were employed to reveal that CDK12 inhibits insulin like growth factor binding protein 3 (IGFBP3). Western blot analysis also demonstrated that CDK12 promoted VEGFA expression by inhibiting IGFBP3, which involves the Akt signaling pathway. Then, CDK12 was found to promote PCa cell proliferation, cell migration and angiogenesis by inhibiting IGFBP3 through cell proliferation assays, cell migration assays and tube formation assays, respectively. Finally, animal experiments were performed for in vivo validation. It was concluded that CDK12 promoted PCa and its angiogenesis by inhibiting IGFBP3.

CDK12 Promotes the Proliferation, Migration, and Angiogenesis of Gastric Carcinoma via Activating the PI3K/AKT/mTOR Signaling Pathway

Cyclin-dependent kinase 12 (CDK12) has been found to regulate tumor progression. However, its function in gastric carcinoma (GC) remains controversial. This work aimed to explore the exact effect of CDK12 on GC progression. We detected the expression of CDK12 in GC cells and normal gastric mucosal epithelial cells. Then CDK12 function on GC cell proliferation, migration, and angiogenesis was researched by colony formation experiment, Transwell experiment, and angiogenesis assay. Moreover, CDK12 effect on the PI3K/AKT/mTOR pathway activity was explored by western blot. Further, we used LY294002 (10 μM) to treat GC cells to verify whether CDK12 regulates GC progression by activating the PI3K/AKT/mTOR pathway. Additionally, CDK12 effect on the expression of prognostic factors of GC was detected by western blot, including alkaline phosphatase (ALP) and Ki67. Quantitative real-time polymerase chain reaction and western blot were utilized to evaluate the expression of mRNAs and proteins. As a result, CDK12 was upregulated in GC cells. CDK12 overexpression facilitated the proliferation, migration, and angiogenesis of GC cells. However, CDK12 silencing showed an opposite result. CDK12 overexpression activated the PI3K/AKT/mTOR pathway, but CDK12 silencing inactivated it in GC cells. The blockage of the PI3K/AKT/mTOR pathway induced by LY294002 treatment counteracted the promotion of CDK12 on the proliferation, migration, and angiogenesis of GC. Further, CDK12 silencing suppressed the expression of ALP and Ki67 proteins in GC cells. Taken together, CDK12 promotes the proliferation, migration, and angiogenesis of GC by activating the PI3K/AKT/mTOR pathway. It may be a novel target for GC treatment.

Metastatic prostate cancer is associated with distinct higher frequency of genetic mutations at diagnosis

INTRODUCTION AND OBJECTIVES

We explored characteristic genetic mutations associated with metastatic prostate cancer (PCa) by comparing next generation sequencing (NGS) data between men with or without metastatic disease at diagnosis.

METHODS

We queried the American Association for Cancer Research Project Genomics Evidence Neoplasia Information Exchange (GENIE) registry for men diagnosed with PCa. Patients were categorized into with (M1) or without metastatic disease (M0) groups. The difference in the frequency of genetic mutations between the two groups and the prognostic significance of the mutations were analyzed using SPSS V28. We included frequency rate of > 5% and P values < 0.05 were considered statistically significant to maintain over 95% true positive detection rate.

RESULTS

Of a total of 10,580 patients with diagnosis of PCa in the dataset, we selected a study cohort of 1268 patients without missing data; 700 (55.2%) had nonmetastatic PCa, 421 (33.2%) and 147 (11.6%) patients had metastatic castration sensitive and resistant PCa respectively. The median age at diagnosis and serum prostate specific antigen (PSA) level for the entire cohort was 62.8 years (IQR 56.3-68.4) and 8.0 ng/ml (IQR 4.9-20.9) respectively. A vast majority of the cohort were of Caucasian ancestry (89.1%). Of a total of 561 genes sequenced, there were mutations in 79 genes (14.1%). The mutation frequency was significantly higher in M1PCa compared to M0PCa, 35.7% and 23.3%, respectively (P = <0.001). The median tumor mutational burden was also significantly higher in the samples from M1PCa (2.59 mut/MB) compared to M0PCa (1.96 mut/MB) (P < 0.001). Compared to M0PCa patients, M1PCa patients demonstrated significantly higher rate of genetic mutations; TP53 (38.73% vs. 17.71% P < 0.001), PTEN (25.70% vs. 11.71% P < 0.001), AR (17.25% vs. 1.43% P < 0.001), APC (11.8% vs. 4.43% P < 0.001), TMPRSS2 (31.5% vs. 11.14% P < 0.001), ERG (23.59% vs. 13.13% P < 0.001), FOXA1 (17.43% vs. 6.33% P < 0.001), MYC (8.45% vs. 2.29% P < 0.001), RB1 (10.39% vs. 2.43% P < 0.001) and CDK12 (8.45% vs. 1.31% P < 0.001).  Of the various cellular signaling pathways, the androgen receptor signaling pathway was most often impacted. In the cohort with M1 disease, compared to men without genetic mutations the men with genetic mutations demonstrated worse survival (P = <0.001, log rank test). Compared to castration sensitive M1 patients, AR (57% vs. 4% P < 0.001), TP53 (50.7% vs. 34% P < 0.001), PTEN (35.2% vs. 22.1% P < 0.001), RB1(23.9% vs. 4.75% P < 0.001) were significantly more frequently mutated in castration resistant M1 patients. In contrast, mutations of SPOP (13.3% vs. 7.9% P < 0.001), FOXA1 (17.6% vs. 5.3% P < 0.001) and CDK12 (12% vs. 6.45% P < 0.001) were significantly more frequently found in castration sensitive M1 patients compared to castration resistant patients.

CONCLUSION

Patients with M1PCa demonstrated characteristic genetic mutations compared to M0PCa, which most often influenced androgen receptor signaling and is associated with worse survival. In addition, we identified distinct genetic mutations between castration sensitive and resistant M1PCa. These findings may be used to further our understanding and management of men with PCa.

Transcription-associated cyclin-dependent kinase 12 (CDK12) as a potential target for cancer therapy

Cyclin-dependent kinase 12 (CDK12), a transcription-related cyclin dependent kinase (CDK), plays a momentous part in multitudinous biological functions, such as replication, transcription initiation to elongation and termination, precursor mRNA (pre-mRNA) splicing, intron polyadenylation (IPA), and translation. CDK12 can act as a tumour suppressor or oncogene in disparate cellular environments, and its dysregulation likely provokes tumorigenesis. A comprehensive understanding of CDK12 will tremendously facilitate the exploitation of novel tactics for the treatment and precaution of cancer. Currently, CDK12 inhibitors are nonspecific and nonselective, which profoundly hinders the pharmacological target validation and drug exploitation process. Herein, we summarize the newly comprehension of the biological functions of CDK12 with a focus on recently emerged advancements of CDK12-associated therapeutic approaches in cancers.

Targeting the Heterogeneous Genomic Landscape in Triple-Negative Breast Cancer through Inhibitors of the Transcriptional Machinery

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer defined by lack of the estrogen, progesterone and human epidermal growth factor receptor 2. Although TNBC tumors contain a wide variety of oncogenic mutations and copy number alterations, the direct targeting of these alterations has failed to substantially improve therapeutic efficacy. This efficacy is strongly limited by interpatient and intratumor heterogeneity, and thereby a lack in uniformity of targetable drivers. Most of these genetic abnormalities eventually drive specific transcriptional programs, which may be a general underlying vulnerability. Currently, there are multiple selective inhibitors, which target the transcriptional machinery through transcriptional cyclin-dependent kinases (CDKs) 7, 8, 9, 12 and 13 and bromodomain extra-terminal motif (BET) proteins, including BRD4. In this review, we discuss how inhibitors of the transcriptional machinery can effectively target genetic abnormalities in TNBC, and how these abnormalities can influence sensitivity to these inhibitors. These inhibitors target the genomic landscape in TNBC by specifically suppressing MYC-driven transcription, inducing further DNA damage, improving anti-cancer immunity, and preventing drug resistance against MAPK and PI3K-targeted therapies. Because the transcriptional machinery enables transcription and propagation of multiple cancer drivers, it may be a promising target for (combination) treatment, especially of heterogeneous malignancies, including TNBC.

Link of sorafenib resistance with the tumor microenvironment in hepatocellular carcinoma: Mechanistic insights

Sorafenib, a multi-kinase inhibitor with antiangiogenic, antiproliferative, and proapoptotic properties, is the first-line treatment for patients with late-stage hepatocellular carcinoma (HCC). However, the therapeutic effect remains limited due to sorafenib resistance. Only about 30% of HCC patients respond well to the treatment, and the resistance almost inevitably happens within 6 months. Thus, it is critical to elucidate the underlying mechanisms and identify effective approaches to improve the therapeutic outcome. According to recent studies, tumor microenvironment (TME) and immune escape play critical roles in tumor occurrence, metastasis and anti-cancer drug resistance. The relevant mechanisms were focusing on hypoxia, tumor-associated immune-suppressive cells, and immunosuppressive molecules. In this review, we focus on sorafenib resistance and its relationship with liver cancer immune microenvironment, highlighting the importance of breaking sorafenib resistance in HCC.

Knockdown of KRAB domain-associated protein 1 suppresses the proliferation, migration and invasion of thyroid cancer cells by regulating P68/DEAD box protein 5

KRAB domain-associated protein 1 (KAP-1) has been reported to be an oncogene in diverse tumors. KAP-1 was found to have abundant existence in malignant thyroid tissues, but its role in thyroid cancer hasn’t been elucidated clearly. This study was carried out to explore the role of KAP-1 in thyroid cancer, and to clarify its molecular mechanism. The expressions of KAP-1 and P68/DEAD box protein 5 (DDX5) were assessed under the help of qRT-PCR and western blot. Then, we downregulated KAP-1 or upregulated DDX5 by cell transfection in TPC-1 cells. A series of cellular experiments on proliferation, apoptosis, migration and invasion were conducted with CCK-8, EdU, TUNEL, wound-healing and Transwell assays. Besides, the relationship between KAP-1 and DDX5 was verified by co-immunoprecipitation (Co-IP). The results showed that both of KAP-1 and DDX5 were upregulated in thyroid cancer cells. Loss-of-function experiments revealed that KAP-1 knockdown imparted suppressive effects on cell proliferation, migration and invasion, but promoted cell apoptosis. Additionally, KAP-1 was demonstrated to interact with DDX5 and positively regulate DDX5 expression. The following rescued experiments exhibited that the inhibitory effects of KAP-1 knockdown on cellular activities of thyroid cancer and Wnt/β-catenin signaling were also partly reversed by DDX5 overexpression. Moreover, activation of Wnt/β-catenin signaling retarded the anti-tumor activity of KAP-1 knockdown. In conclusion, the data in this study disclosed that KAP-1 silence helped to repress the cell proliferation, migration and invasion by degrading DDK5, so as to hinder the development of thyroid cancer.

The promise and current status of CDK12/13 inhibition for the treatment of cancer

CDK12 and CDK13 are Ser/Thr protein kinases that regulate transcription and co-transcriptional processes. Genetic silencing of CDK12 is associated with genomic instability in a variety of cancers, including difficult-to-treat breast, ovarian, colorectal, brain and pancreatic cancers, and is synthetic lethal with PARP, MYC or EWS/FLI inhibition. CDK13 is amplified in hepatocellular carcinoma. Consequently, selective CDK12/13 inhibitors constitute powerful research tools as well as promising anti-cancer therapeutics, either alone or in combination therapy. Herein the authors discuss the role of CDK12 and CDK13 in normal and cancer cells, describe their utility as a biomarker and therapeutic target, review the medicinal chemistry optimization of existing CDK12/13 inhibitors and outline strategies for the rational design of CDK12/13 selective inhibitors.

CDK12: a potential therapeutic target in cancer

Cyclin-dependent kinase (CDK) 12 engages in diversified biological functions, from transcription, post-transcriptional modification, cell cycle, and translation to cellular proliferation. Moreover, it regulates the expression of cancer-related genes involved in DNA damage response (DDR) and replication, which are responsible for maintaining genomic stability. CDK12 emerges as an oncogene or tumor suppressor in different cellular contexts, where its dysregulation results in tumorigenesis. Current CDK12 inhibitors are nonselective, which impedes the process of pharmacological target validation and drug development. Herein, we discuss the latest understanding of the biological roles of CDK12 in cancers and provide molecular analyses of CDK12 inhibitors to guide the rational design of selective inhibitors.