Kinesin spindle protein inhibitors in cancer: a patent review (2008 - present)

The role of kinesin superfamily proteins in hepatocellular carcinoma

The most prevalent form of primary liver cancer, hepatocellular carcinoma (HCC) poses a significant global health challenge due to its limited therapeutic options. Researchers are currently focused on the complex molecular landscape that governs the initiation and progression of HCC in order to identify new avenues for diagnosis, prognosis, and treatment. In the context of HCC, the Kinesin Superfamily Proteins (KIFs) have become critical regulators of cellular processes, prompting a growing interest in their function among the diverse array of molecular actors implicated in cancer. The KIFs, a family of microtubule-based molecular motors, are renowned for their essential roles in the dynamics of mitotic spindles and intracellular transport. Beyond their well-established functions in normal cellular physiology, emerging evidence indicates that dysregulation of KIFs significantly contributes to the pathogenesis of HCC. Novel therapeutic targets and diagnostic markers are revealed through the unique opportunity to comprehend the complex interplay between KIFs and the molecular events that drive HCC.

Microtubule-Targeting Agents: Disruption of the Cellular Cytoskeleton as a Backbone of Ovarian Cancer Therapy

Microtubules are dynamic polymers composed of α- and β-tubulin heterodimers. Microtubules are universally conserved among eukaryotes and participate in nearly every cellular process, including intracellular trafficking, replication, polarity, cytoskeletal shape, and motility. Due to their fundamental role in mitosis, they represent a classic target of anti-cancer therapy. Microtubule-stabilizing agents currently constitute a component of the most effective regimens for ovarian cancer therapy in both primary and recurrent settings. Unfortunately, the development of resistance continues to present a therapeutic challenge. An understanding of the underlying mechanisms of resistance to microtubule-active agents may facilitate the development of novel and improved approaches to this disease.

Improving Localized Radiotherapy for Glioblastoma via Small Molecule Inhibition of KIF11

Glioblastoma, IDH-wild type (GBM) is the most common and lethal malignant primary brain tumor. Standard of care includes surgery, radiotherapy, and chemotherapy with the DNA alkylating agent temozolomide (TMZ). Despite these intensive efforts, current GBM therapy remains mainly palliative with only modest improvement achieved in overall survival. With regards to radiotherapy, GBM is ranked as one of the most radioresistant tumor types. In this study, we wanted to investigate if enriching cells in the most radiosensitive cell cycle phase, mitosis, could improve localized radiotherapy for GBM. To achieve cell cycle arrest in mitosis we used ispinesib, a small molecule inhibitor to the mitotic kinesin, KIF11. Cell culture studies validated that ispinesib radiosensitized patient-derived GBM cells. In vivo, we validated that ispinesib increased the fraction of tumor cells arrested in mitosis as well as increased apoptosis. Critical for the translation of this approach, we validated that combination therapy with ispinesib and irradiation led to the greatest increase in survival over either monotherapy alone. Our data highlight KIF11 inhibition in combination with radiotherapy as a new combinatorial approach that reduces the overall radioresistance of GBM and which can readily be moved into clinical trials.

Kinesin spindle protein inhibitors in cancer: from high throughput screening to novel therapeutic strategies

Bringing to a halt the cell cycle in mitosis and interfering with its normal progression is one of the most successful anti-cancer strategies used nowadays. Classically, several kinds of anti-cancer drugs like taxanes and vinca alkaloids directly inhibit microtubules during cell division. These drugs exhibit serious side effects, most importantly, severe peripheral neuropathies. Alternatively, KSP inhibitors are grasping a lot of research attention as less toxic mitotic inhibitors. In this review, we track the medicinal chemistry developmental stages of KSP inhibitors. Moreover, we address the challenges that are faced during the development of KSP inhibitor therapy for cancer and future insights for the latest advances in research that are directed to find active KSP inhibitor drugs.

Scientists have recognized the importance of selective KSP inhibitors in the early 2000s and so various KSP protein inhibitors have been investigated. Only ten of these have been clinically evaluated for cancer treatment. Ispinesib (SB-715992) and filanesib (Arry-520) were the most promising small molecules in clinical trials against the KSP protein. Many challenges are faced during the development of an active anti-KSP drug; most importantly are the unsatisfactory clinical trial results. Designing dual inhibitors, antibody–drug conjugates, combination therapy and gene therapy approach are among the main strategies that are being investigated nowadays to find new effective KSP inhibitors. The scientific research efforts are still devoted to find an effective and tolerable KSP inhibitor drug that can gain US FDA approval.

KSP inhibitor SB743921 inhibits growth and induces apoptosis of breast cancer cells by regulating p53, Bcl-2, and DTL

Kinesin spindle protein (KSP) is a microtubule-associated motor protein that is specifically expressed by mitosis cells. It is highly expressed in various types of tumors including hematomalignances and solid tumors. Chemical KSP inhibition has become a novel strategy in the development of anticancer drugs. SB743921 is a selective inhibitor for KSP, which is a mitotic protein essential for cell-cycle progression. Although SB743921 has shown antitumor activities for several types of cancers and entered into clinical trials, its therapeutic effects on breast cancer and mechanisms have not been explored. In this study, we tested the antitumor activity of SB743921 in breast cancer cell lines and partly elucidated its mechanisms. KSP and denticleless E3 ubiquitin–protein ligase homolog (DTL) are overexpressed in breast cancer cells compared with no-cancer tissues. Chemical inhibition of KSP by SB743921 not only reduces proliferation but also induces cell-cycle arrest and leads to apoptosis in breast cancer cells. Treatment of MCF-7 and MDA-MB-231 breast cancer cell lines with SB743921 results in decreased ability of colony formation in culture. SB743921 treatment also causes a KSP accumulation in protein level that is associated with cell arrest. Furthermore, we showed that SB743921 treatment significantly reduces the expression of bcl-2 and cell cycle-related protein DTL, and upregulates p53 and caspase-3 in breast cancer cells. Taken together, these data indicated that SB743921 can be expected to be a novel treatment agent for breast cancers.

C-terminal kinesin motor KIFC1 participates in facilitating proper cell division of human seminoma

C-terminus kinesin motor KIFC1 is known for centrosome clustering in cancer cells with supernumerary centrosomes. KIFC1 crosslinks and glides on microtubules (MT) to assist normal bipolar spindle formation to avoid multi-polar cell division, which might be fatal. Testis cancer is the most common human cancer among young men. However, the gene expression profiles of testis cancer is still not complete and the expression of the C-terminus kinesin motor KIFC1 in testis cancer has not yet been examined. We found that KIFC1 is enriched in seminoma tissues in both mRNA level and protein level, and is specifically enriched in the cells that divide actively. Cell experiments showed that KIFC1 may be essential in cell division, but not essential in metastasis. Based on subcellular immuno-florescent staining results, we also described the localization of KIFC1 during cell cycle. By expressing ΔC-FLAG peptide in the cells, we found that the tail domain of KIFC1 might be essential for the dynamic disassociation of KIFC1, and the motor domain of KIFC1 might be essential for the degradation of KIFC1. Our work provides a new perspective for seminoma research.

MiR-20a-5p represses multi-drug resistance in osteosarcoma by targeting the KIF26B gene

BACKGROUND

Chemoresistance hinders curative cancer chemotherapy in osteosarcoma (OS), resulting in only an approximately 20 % survival rate in patients with metastatic disease at diagnosis. Identifying the mechanisms responsible for regulating chemotherapy resistance is crucial for improving OS treatment.

METHODS

This study was performed in two human OS cell lines (the multi-chemosensitive OS cell line G-292 and the multi-chemoresistant OS cell line SJSA-1). The levels of miR-20a-5p and KIF26B mRNA expression were determined by quantitative real-time PCR. KIF26B protein levels were determined by western blot analysis. Cell viability was assessed by MTT assay. Apoptosis was evaluated by flow cytometry.

RESULTS

We found that miR-20a-5p was more highly expressed in G-292 cells than in SJSA-1 cells. Forced expression of miR-20a-5p counteracted OS cell chemoresistance in both cell culture and tumor xenografts in nude mice. One of miR-20a-5p's targets, kinesin family member 26B (KIF26B), was found to mediate the miR-20a-5p-induced reduction in OS chemoresistance by modulating the activities of the MAPK/ERK and cAMP/PKA signaling pathways.

CONCLUSIONS

In addition to providing mechanistic insights, our study revealed that miR-20a-5p and KIF26B contribute to OS chemoresistance and determined the roles of these genes in this process, which may be critical for characterizing drug responsiveness and overcoming chemoresistance in OS patients.

KIFC1: a promising chemotherapy target for cancer treatment?

The kinesin motor KIFC1 has been suggested as a potential chemotherapy target due to its critical role in clustering of the multiple centrosomes found in cancer cells. In this regard, KIFC1 seems to be non-essential in normal somatic cells which usually possess only two centrosomes. Moreover, KIFC1 is also found to initiatively drive tumor malignancy and metastasis by stabilizing a certain degree of genetic instability, delaying cell cycle and protecting cancer cell surviving signals. However, that KIFC1 also plays roles in other specific cell types complicates the question of whether it is a promising chemotherapy target for cancer treatment. For example, KIFC1 is found functionally significant in vesicular and organelle trafficking, spermiogenesis, oocyte development, embryo gestation and double-strand DNA transportation. In this review we summarize a recent collection of information so as to provide a generalized picture of ideas and mechanisms against and in favor of KIFC1 as a chemotherapy target. And we also drew the conclusion that KIFC1 is a promising chemotherapy target for some types of cancers, because the side-effects of inhibiting KIFC1 mentioned in this review are theoretically easy to avoid, while KIFC1 is functionally indispensable during mitosis and malignancy of multi-centrosome cancer cells. Further investigations of how KIFC1 is regulated throughout the mitosis in cancer cells are needed for the understanding of the pathways where KIFC1 is involved and for further exploitation of indirect KIFC1 inhibitors.

High-throughput screening for small molecule modulators of motor protein Kinesin

The kinesin superfamily of motor proteins are involved in the active transport of a large number of cargos such as organelles, proteins, and RNAs from the neuronal cell body to distal neuronal processes. Previously, we have shown that kinesin-mediated axonal transport of proteins and RNAs are important for long-term memory storage. Identification of small molecules that can activate or inhibit kinesins is of specific interest due to the significance of kinesin-mediated functions in neuronal health and plasticity. Here, we describe a high-throughput screening assay designed to specifically identify compounds that inhibit or activate adenosine triphosphatase activity of the kinesin 5B of humans. The luminescence-based assay that we developed is highly reproducible and robust. Using this approach, we screened a pharmacologically characterized compound collection and have identified small molecules with either activator or inhibitor-like activity. To further characterize screening hits, we also developed an orthogonal assay based on absorbance and a counter screen assay based on luminescence. Development of such assays is important to help identify small molecules that can be used in potential drug development efforts targeted at modulating the function of kinesin.

Elevated kinesin family member 26B is a prognostic biomarker and a potential therapeutic target for colorectal cancer

Background

Kinesins play a key role in the development and progression of many human cancers. The present study investigated the expression and clinical significance of kinesin family member 26B (KIF26B) in colorectal cancer (CRC).

Methods

Using quantitative real-time PCR and Western blot analyses as well as immunohistochemical staining of a tissue microarray we examined KIF26B mRNA and protein levels in CRC tumor tissues and paired adjacent normal mucosa. Moreover, the effect of KIF26B knockdown on CRC cell proliferation was investigated using Cell Counting Kit-8 assays.

Results

Expression of KIF26B was found to be elevated in CRC. Suppression of KIF26B inhibited CRC cell proliferation. Furthermore, upregulated expression of KIF26B was significantly correlated with tumor size (P = 0.020), American Joint Committee on Cancer (AJCC) stage (P = 0.018), T stage (P = 0.026), N stage (P = 0.013), and differentiation histology (P = 0.047). KIF26B was also shown to be an independent prognostic indicator of overall survival for CRC patients (HR 5.621; 95% CI 2.302–13.730; P < 0.001).

Conclusion

Our data indicate that KIF26B plays an important role in colorectal carcinogenesis and functions as a novel prognostic indicator and a potential therapeutic target for CRC.