Antimitotic Research Articles

A pan-cancer analysis of homeobox family: expression characteristics and latent significance in prognosis and immune microenvironment

BackgroundThe Homeobox (HOX) gene family are conserved transcription factors that are essential for embryonic development, oncogenesis, and cancer suppression in biological beings. Abnormally expressed HOX genes in cancers are directly associated with prognosis.MethodsPublic databases such as TCGA and the R language were used to perform pan-cancer analyses of the HOX family in terms of expression, prognosis, and immune microenvironment. The HOX score was defined, and potential target compounds in cancers were predicted by Connective Map. Immunohistochemistry was employed to validate protein expression levels. Gene knockdowns were used to verify the effects of HOXB7 and HOXC6 on the proliferation and migration of lung adenocarcinoma (LUAD) cells.ResultsHOX genes play different roles in different cancers. Many HOX genes, especially HOXB7 and HOXC6, have higher expression and lower overall survival in specific cancers and are predicted as risk factors. The high expression of most HOX genes is mainly related to immune subtypes C1-C4 and C6. Potential anti-tumor compounds for down-regulating HOX gene expression were identified, such as HDAC inhibitors and tubulin inhibitors. LUAD Cell migration and proliferation were inhibited when HOXB7 or HOXC6 was knocked down.ConclusionsMany HOX genes may act as both oncogenes and tumor suppressor genes, necessitating precision medicine based on specific cancers. The HOX gene family plays a crucial role in the development of certain cancers, and their expression patterns are closely related to cancer prognosis and the tumor microenvironment (TME), which may affect cancer prognosis and response to immunotherapy. Compounds that are negatively correlated with the expression levels of the HOX family in various cancers, such as HDAC inhibitors, are potential anti-cancer drugs. HOXB7 and HOXC6 may serve as potential targets for cancer treatment and the development of targeted compounds in the future.

Microtubule inhibition as a proposed mechanism for the anthelmintic effect of phytochemicals isolated from Cicerbita alpina

The alpine plant Cicerbita alpina (L.) Wallr., when grown as a sprout, is known as a bitter-tasting culinary delicacy. Recently it has also been reported to have anthelmintic activity, prompting further investigation into its mechanism of action. Liquid–liquid fractions were prepared from a methanolic extract of the aerial parts and were submitted in parallel to embryo development (ED), worm motility (WMT), and cytotoxicity assays for anthelmintic and toxicity evaluations. The anthelminthic assays revealed the more polar fractions to be most active against Ascaridia galli embryos (BuOH | 68% ED | c = 500 µg/ml and EtOAc | 65% ED | c = 500 µg/ml) and Caenorhabditis elegans adult worms (BuOH | 49% WMT | c = 150 µg/ml and EtOAc | 74% WMT | c = 150 µg/ml) suggesting the fraction’s constituents possess dual anthelmintic activity against multiple life-cycle stages (i.e., eggs, worms) of helminths. Additionally, the BuOH fraction was non-cytotoxic to human cell-lines. Subsequent FCC and SEC derived subfractions were submitted to the anthelmintic assay workflow and the enriched subfractions B1 and E3.8, phytochemically assigned as 11-β,13-dihydrolactucin and luteolin, demonstrated bioactivity against the embryo phenotype (B1 | 58% ED | c = 1.8 µM and E3.8 | 46% ED | c = 1.7 µM) within range of the flubendazole control. Furthermore, luteolin was found to inhibit C. elegans egg hatching (luteolin | 65% EH | c = 10 µM | t = 10 h) within the range of the control albendazole. Both identified anthelmintic phytochemicals were found to affect tubulin polymerisation at a concentration of c = 50 µM. Together with in silico virtual screening studies, these results suggest microtubule stabilisation as a possible anthelmintic target and mechanism of action. This work effectively advocates the consideration of C. alpina extracts and fractions for the development of herbal therapeutics against parasitic helminths.

Leveraging large-scale PDO-based assays to optimize antibody-drug conjugate efficacy in CRC.

261 Background: Clinical trials are one of the major barriers in contemporary drug development. Functional assays based on patient-derived organoids (PDO) are a promising new tool for derisking clinical development of new therapies, but their use has been limited due to small cohort sizes and the absence of systematic validation studies. Using the largest cohort of matched PDOs, longitudinal clinical data, transcriptomic and WES data in CRC, we explore the use of large PDOs collections to characterize ADC efficacy and affinity through systematic mapping of the relationship between target antigen affinity and payload efficacy. Methods: We have assembled a collection of 85 PDOs from colorectal cancer (CRC), generated from primary tumour samples and metastatic biopsies. Patients ranged from 32 to 89 years old and had experienced an average of 1.54 lines of treatment prior to the PDO-generating tissue sampling. Using gene expression levels of well known target antigens such as CEACAM5, ERBB2, MSLN and TROP2 as a proxy for protein concentration, we explore the relationship between the target antigen affinity and the efficacy of a subset of common payloads including topoisomerase and microtubule inhibitors. This allows us to identify the relationship between two of the three main vectors of ADC efficacy in CRC. Results: We show that topoismerase inhibitor and microtubule inhibitor efficacy relates to the RNA expression level of multiple target antigens commonly used in active clinical trials in CRC. These data match the target antigen and payload couples currently under development or approved in the clinic. We are developing a tool to optimize clinical trial design. This approach will allow us to match patients more accurately with the appropriate payload, ensuring a higher likelihood of response. Conclusions: We report that large-scale PDO-based assays can be a useful tool to anticipate clinical readouts. This work suggests that well-characterized PDO collections could also help redefine patient populations, increasing the likelihood of identifying those more likely to respond to a given ADC, and thus improving the success rates of clinical studies for new treatments in CRC.

AGX101: A TM4SF1-directed tubulin inhibitor conjugate in ongoing first-in-human trial including GI cancers.

829 Background: TM4SF1 (Transmembrane-4 L-Six-Family-Member-1) is an endothelial marker with critical roles in angiogenesis, as well as a tumor cell antigen that contributes significantly to invasion and metastasis. TM4SF1 is upregulated 20-fold in angiogenic tumor vascular endothelium compared to normal vasculature endothelium and exhibits a unique nuclear internalization pathway. AGX101 is a novel tubulin inhibitor conjugate specifically directed against TM4SF1, delivering a potent maytansinoid payload directly to the nucleus of cells within the tumor microenvironment. Delivery to both the vascular and tumor cell compartments of the tumor results in three mechanisms of action (MoAs): (1) activation of tumor immune surveillance, (2) tumor blood supply deprivation, and (3) direct tumor cell killing. Methods: TM4SF1 expression was assessed using immunohistochemistry. Safety and pharmacokinetics of AGX101 were evaluated in non-human primates (NHP), with escalating doses to determine the highest non-severely toxic dose (HNSTD). Efficacy studies were also conducted in mouse models, enabling assessment of the minimum effective dose (MED) needed to engage each of the three MoAs. The combination of HNSTD and MED enables calculation of a therapeutic index (TI). The potential for synergy with immune checkpoint inhibitors (ICIs) was also investigated. A first-in-human study of AGX101 in patients with advanced solid tumors with the primary objective of safety and dose-limiting toxicities (DLTs) has initiated. Results: Notable cancers with high TM4SF1 scoring intensity include pancreatic adenocarcinoma, hepatocellular carcinoma, cholangiocarcinoma, and gastric cancer. In esophageal cancer, 20% of patients have a TM4SF1 copy number amplification, and these have worse prognosis. In NHP, AGX101 exhibited a favorable safety profile. In preclinical efficacy studies, monotherapy demonstrated robust efficacy through each of the three MoAs in syngeneic models in mice including CT26 colon carcinoma, and human tumor xenograft models including MIA PaCa-2 pancreatic cancer. Measured by exposure, TI was large. In syngeneic mouse models including CT26, the effects of ICIs were potentiated, suggesting a potential synergistic approach in cancer therapy. The first two dose levels of AGX101 monotherapy in humans has cleared without DLTs. Three patients with pancreatic adenocarcinoma have been treated thus far. Conclusions: AGX101, targeting the TM4SF1 antigen, represents a promising new approach in cancer therapy. The preclinical data suggest that AGX101 could provide a significant therapeutic benefit by novel and differentiated mechanisms of action, namely selectively targeting the tumor vasculature and potentiating immune-based therapies. Further clinical development of AGX101 is ongoing and initial outcome data will become available by the conference. Clinical trial information: NCT06440005 .

Cytology and Yields Analysis of Onions (Allium cepa l.) under Compost Application in Coastal Saline Soil

Onion (Allium cepa L.) is a valuable crop in Bangladesh for its diversified usage and availability of enriched germplasms including local and exotic ones. However, the cultivation of onions in the coastal regions of Bangladesh has become a major challenge because of salinity and soil fertility. Therefore, a pot experiment of coastal saline soil amendment with compost was carried out with mostly cultivated varieties i.e. Taherpuri and King. The treatments T1 (2.5 t/ha) and T2 (5.0 t/ha) significantly improved the plant height for the Taherpuri variety and revealed an escalation to the no. of the leaflet, root length and bulb diameter for the King variety. Compost application on saline soil didn’t increase the mitotic index (MI%) for all the treatments for both of the experimented varieties but increased the mitotic inhibition index (MII%) for the treatments T3 (7.5 t/ha) and T4 (10.0 t/ha) treatment for the Taherpuri and King varieties respectively. The correlation coefficient between the treatment and different yields of onion was found better for the Taherpuri than the King variety. J. Asiat. Soc. Bangladesh, Sci. 50(1-2): 89-99, June-December 2024

Exploring Integrin α5β1 as a Potential Therapeutic Target for Pulmonary Arterial Hypertension: Insights From Comprehensive Multicenter Preclinical Studies.

Pulmonary arterial hypertension (PAH) is characterized by obliterative vascular remodeling of the small pulmonary arteries (PAs) and progressive increase in pulmonary vascular resistance leading to right ventricular failure. Although several drugs are approved for the treatment of PAH, mortality rates remain high. Accumulating evidence supports a pathological function of integrins in vessel remodeling, which are gaining renewed interest as drug targets. However, their role in PAH remains largely unexplored. The expression of the RGD (arginylglycylaspartic acid)-binding integrin α5β1 was assessed in PAs, PA smooth muscle cells, and PA endothelial cells from patients with PAH and controls using NanoString, immunoblotting, and Mesoscale Discovery assays. RNA sequencing was conducted to identify gene networks regulated by α5β1 inhibition in PAH PA smooth muscle cells. The therapeutic efficacy of α5β1 inhibition was evaluated using a novel small molecule inhibitor and selective neutralizing antibodies in Sugen/hypoxia and monocrotaline rat models, with validation by an external contract research organization. Comparisons were made against standard-of-care therapies (ie, macitentan, tadalafil) and sotatercept and efficacy was assessed using echocardiographic, hemodynamic, and histological assessments. Ex vivo studies using human precision-cut lung slices were performed to further assess the effects of α5β1 inhibition on pulmonary vascular remodeling. We found that the arginine-glycine-aspartate RGD-binding integrin α5β1 is upregulated in PA endothelial cells and PA smooth muscle cells from patients with PAH and remodeled PAs from animal models. Blockade of the integrin α5β1 or depletion of the α5 subunit downregulated FOXM1 (forkhead box protein M1)-regulated gene networks, resulting in mitotic defects and inhibition of the pro-proliferative and apoptosis-resistant phenotype of PAH cells. We demonstrated that α5β1 integrin blockade safely attenuates pulmonary vascular remodeling and improves hemodynamics and right ventricular function and matched or exceeded the efficacy of standard of care and sotatercept in multiple preclinical models. Ex vivo studies further validated its potential in reversing advanced remodeling in human precision-cut lung slices. These findings establish α5β1 integrin as a pivotal driver of PAH pathology and we propose its inhibition as a novel, safe, and effective therapeutic strategy for PAH.

Osmotic stress influences microtubule drug response via WNK1 kinase signaling.

Ion homeostasis is critical for numerous cellular processes, and disturbances in ionic balance underlie diverse pathological conditions, including cancer progression. Targeting ion homeostasis is even considered as a strategy to treat cancer. However, very little is known about how ion homeostasis may influence anticancer drug response. In a genome-wide CRISPR-Cas9 resistance drug screen, we identified and validated the master osmostress regulator WNK1 kinase as a modulator of the response to the mitotic inhibitor rigosertib. Osmotic stress and WNK1 inactivation lead to an altered response not only to rigosertib treatment but also to other microtubule-related drugs, minimizing the prototypical mitotic arrest produced by these compounds. This effect is due to an alteration in microtubule stability and polymerization dynamics, likely maintained by fluctuations in intracellular molecular crowding upon WNK1 inactivation. This promotes resistance to microtubule depolymerizing compounds, and increased sensitivity to microtubule stabilizing drugs. In summary, our data proposes WNK1 osmoregulation activity as an important modulator for microtubule-associated chemotherapy response.

(E)-1-(3-(3-Hydroxy-4-Methoxyphenyl)-1-(3,4,5-Trimethoxyphenyl)allyl)-1H-1,2,4-Triazole and Related Compounds: Their Synthesis and Biological Evaluation as Novel Antimitotic Agents Targeting Breast Cancer.

Background/Objectives: The synthesis of (E)-1-(1,3-diphenylallyl)-1H-1,2,4-triazoles and related compounds as anti-mitotic agents with activity in breast cancer was investigated. These compounds were designed as hybrids of the microtubule-targeting chalcones, indanones, and the aromatase inhibitor letrozole. Methods: A panel of 29 compounds was synthesized and examined by a preliminary screening in estrogen receptor (ER) and progesterone receptor (PR)-positive MCF-7 breast cancer cells together with cell cycle analysis and tubulin polymerization inhibition. Results: (E)-5-(3-(1H-1,2,4-triazol-1-yl)-3-(3,4,5-trimethoxyphenyl)prop-1-en-1-yl)-2-methoxyphenol 22b was identified as a potent antiproliferative compound with an IC50 value of 0.39 mM in MCF-7 breast cancer cells, 0.77 mM in triple-negative MDA-MB-231 breast cancer cells, and 0.37 mM in leukemia HL-60 cells. In addition, compound 22b demonstrated potent activity in the sub-micromolar range against the NCI 60 cancer cell line panel including prostate, melanoma, colon, leukemia, and non-small cell lung cancers. G2/M phase cell cycle arrest and the induction of apoptosis in MCF-7 cells together with inhibition of tubulin polymerization were demonstrated. Immunofluorescence studies confirmed that compound 22b targeted tubulin in MCF-7 cells, while computational docking studies predicted binding conformations for 22b in the colchicine binding site of tubulin. Compound 22b also selectively inhibited aromatase. Conclusions: Based on the results obtained, these novel compounds are suitable candidates for further investigation as antiproliferative microtubule-targeting agents for breast cancer.

Synthesis and Biological Evaluation of New cis-Restricted Triazole Analogues of Combretastatin A-4.

The natural products combretastatins A-1 and A-4 are potent antimitotic and vascular-disrupting agents through their binding at the colchicine site in tubulin. However, these compounds suffer from a low water solubility and a tendency to isomerize to the inactive trans stilbenes. In this study, we have prepared a series of 18 cis-restricted triazole analogues of combretastatin A-4 (CA-4), maintaining, in all cases, the 3,4,5-trimethoxy phenyl ring A, with the aim of investigating the substitution pattern on the B-ring in a systematic way. To this end, cytotoxic activities of the cis-restricted analogues of CA-4 prepared were determined in two tumor cell lines, namely, HT-29 and A-549, as well as in the non-tumor cell line HEK-293, to pre-evaluate the selectivity profile of the compounds for the tumor cell lines. The main conclusion was the essential presence of methoxyl or ethoxyl groups at the para position of the B-ring in order to obtain good antitumor activities. Thus, the more active compounds in our study displayed IC50 values in the nanomolar range for the tumor cell lines but not for the normal cells. Consequently, these triazole analogues of CA-4 could serve as promising alternatives to the natural product, although further studies about their biological activity are essential in order to fully determine their viability as therapeutic agents in the treatment of cancer.

Current Insights into Various In Vitro Dihaploidization Techniques Used in Brassica Oil Crops

Brassicas are considered the third most important source of vegetable oil globally. With the escalating production of Brassica varieties, there is growing demand for high-yielding genotypes. Doubled haploid (DH) techniques have become very popular in various Brassica breeding programs. Such DH techniques can play a significant role in plant breeding by accelerating the production of homozygous lines and increasing selection efficiency. Among these methods, isolated microspore culture stands out as the most effective, facilitating the generation of a higher number of embryos compared to conventional methods of plant breeding. Different chemical compounds such as herbicides, brassinosteroids, and polyethylene glycol have an antimitotic effect and have been found to generate DH plants and improve microspore embryogenesis in Brassica species. Colchicine and trifluralin have proven to be efficient chromosome-doubling agents as well as important supplements that can increase the rate of embryogenesis. This review serves as a comprehensive summary and effectiveness evaluation of the latest research findings in the Brassica oil crops to help increase efficiency of the future research focusing on DH methods and application of antimitotic agents in the various oilseed species of the genus Brassica.

Simultaneous Quantification of Total Antibody and Conjugated Payload for DS001 in Rat Serum Using a Hybrid Immuno-Capture LC-MS/MS.

Antibody-drug conjugates (ADCs) are intricate compounds that pose significant challenges in bioanalytical characterization. Therefore, multiple bioanalytical methods are required to comprehensively elucidate their pharmacokinetic (PK) profiles. In this study, we investigated DS001, an ADC consisting of a humanized monoclonal antibody (hRS7), a cleavable chemical linker, and the microtubule inhibitor monomethyl auristatin E (MMAE), with a drug-to-antibody ratio (DAR) of 8. This study established a rapid and sensitive hybrid immunoaffinity liquid-chromatography-tandem-mass-spectrometry (LC-MS/MS) approach for the simultaneous quantification of the total antibody and the enzymatically cleavable conjugated payload of DS001. This method is capable of monitoring fluctuations in average DAR values during PK assessments. The sample preparation procedure involved immunocapture, denaturation, trypsin digestion, papain digestion, and termination, all completed within a total processing time of less than 4h. The method demonstrated linearity for the total antibody in the range of 100ng/mL (lower-limit-of-quantification, LLOQ) to 100,000ng/mL, and for the conjugated payload from 3.495ng/mL (LLOQ) to 3495ng/mL in rat serum. Both analytes exhibited standard curve correlation coefficients (r) greater than 0.990 within their respective linear ranges. The precision and accuracy of the method were within ± 15% (± 20% for LLOQ). The verified LC-MS/MS approach was successfully employed in the PK analysis following intravenous administration of 0.2mg/kg DS001 in rats via tail vein injection.

Artificial Induction of Polyploidy in Blueberry Breeding: A Review

Blueberry planted acreage has increased rapidly during the past four decades, and blueberry consumption has kept pace. The environments across blueberry growing regions are highly heterogeneous. Variable factors include weather, soils, cultivation practices, biotic stress, and abiotic stress. Broadening the genetic diversity of the blueberry breeding gene pool will enable the development of blueberry cultivars adapted to specific growing regions. The primary gene pool for blueberry breeders includes cultivated tetraploids and hexaploids. The tetraploids include cultivars and advanced selections of northern highbush, southern highbush, lowbush, and half highbush; the hexaploids are the rabbiteye cultivars. The secondary gene pool encompasses diploid, tetraploid, and hexaploid wild blueberries in Vaccinium section Cyanococcus. The tertiary gene pool consists of 300 to 400 Vaccinium species in sections other than Cyanococcus. These are native to many parts of the world. Blueberry breeding began with interspecific hybrids in section Cyanococcus. Subsequent breeding has used diploid, tetraploid, and hexaploid Cyanococcus species with limited use of species from other Vaccinium sections. A strong triploid block and partial to total sterility in progeny from heteroploid crosses have limited the use of some species in breeding. Unreduced gametes allow the production of tetraploid hybrids from diploid × tetraploid crosses and hexaploid hybrids from triploid × hexaploid and triploid × triploid crosses. Production of polyploids by in vitro and in vivo treatments with antimitotic agents can expedite interspecific and intersectional hybridization. This review addresses the contribution of artificial induction of polyploidy to blueberry genetic improvement and discusses additional possible applications of artificial induction of polyploidy for blueberry breeding.

Design, synthesis and anti-tumor evaluation of novel pyrimidine and quinazoline analogues.

Disrupting microtubule dynamics has emerged as a promising strategy for cancer therapy. Novel trimethoxyanilino-substituted pyrimidine and quinazoline derivatives were designed and synthesized to serve as potent microtubule-inhibiting agents with anti-proliferative activity. Compound 2k demonstrates high efficacy against B16-F10 cancer cells at low nanomolar concentrations, with an IC50 of 0.098±0.006μM, which is comparable to colchicine. Mechanistic studies have revealed that 2k has the ability to inhibit microtubule protein polymerization in vitro, resulting in cell cycle arrest and apoptosis. Furthermore, 2k inhibits tumor cell migration and exhibits significant anti-tumor efficacy in a melanoma tumor model without causing obvious toxicity. In summary, the pyrimidine derivative 2k exhibits excellent anticancer activity and provides a new scaffold for the development of novel microtubule inhibitors, which deserves further in-depth research.

Kojic Acid Derivative as an Antimitotic Agent That Selectively Kills Tumour Cells.

Background/Objectives: The primary method used to pharmacologically arrest cancer development and its metastasis is to disrupt the cell division process. There are a few approaches that may be used to meet this objective, mainly through inhibiting DNA replication or mitosis. Despite intensive studies on new chemotherapeutics, the biggest problem remains the side effects associated with the inhibition of cell division in non-tumoural host cells. Methods: The efficacy and selectivity of the kojic acid derivative (L1) was studied in vitro with the use of tumoural (Caco2, SW480, HT29, T98G) and non- tumoural (HEK293T, RAW) cell lines. Light and electron microscopy observations were supported by the next generation sequencing (NGS), cytoflow, and spectroscopy analysis of mRNA and biomolecules, respectively. Results: The light and electron microscopy observations showed that L1 treatment leads to significant morphological changes in Caco2 cells, which are characteristic of mitosis arrest. Moreover, the fluorescent tubulin staining revealed the formation of tubulin ring structure associated with the apoptotic stage. Mitotic exit into apoptosis was further conformed by the cytoflow of early/late apoptosis stages and caspase-3 analysis. NGS investigation showed differentiated expressions of genes involved in mitosis and apoptosis processes. The observed IC50 in tumoural cell lines were as follows: Caco2 (IC50 = 68.2 mM), SW480 (IC50 = 15.5 mM), and HT29 (IC50 = 4.7 mM). Conclusions: The findings presented here suggest that L1 could be a valid candidate for oral prevention and/or chemotherapy in colorectal cancer. Considering high selectivity of L1 versus tumoural cell lines, more in-depth mechanistic studies could reveal unknown stages in carcinogenesis.

C118P Suppresses Gastric Cancer Growth via Promoting Autophagy-Lysosomal Degradation of RAB1A.

Background/Objectives: Gastric cancer (GC) is the leading cause of cancer-related deaths worldwide. C118P, a microtubule inhibitor with anti-angiogenic and vascular-disrupting activities, was proven to be cytotoxic to various cancer cell lines. This study aimed to explore the anti-tumor effect of C118P against gastric cancer and identify its potential target. Methods: The MTT assay, colony formation assay, and EdU incorporation assay were used to evaluate the effect of C118P on GC cell proliferation. Cell cycle and cell apoptosis were measured using flow cytometry. Molecular docking, a microscale thermophoresis (MST) analysis, and the cellular thermal shift assay (CETSA) were used to investigate the binding of C118P to RAB1A. Autophagy-related effects were evaluated by using the MDC staining assay, immunofluorescence assay, and immunoblotting assay. The SGC-7901 cell line xenograft mouse model was used to confirm the anti-tumor efficacy of C118P. Results: C118P dramatically inhibited proliferation, induced G2/M cell cycle arrest, and triggered apoptosis in GC cell lines HGC-27 and SGC-7901. Mechanistically, C118P was demonstrated to bind with RAB1A and reduce the RAB1A protein level, accompanied by the inhibition of mTORC1 signaling. Moreover, C118P induced autophagosome formation and promoted RAB1A protein degradation in an autophagy-lysosomal-dependent manner. The in vivo study verified that C118P inhibits GC growth by inhibiting the RAB1A-mTOR axis. Conclusions: Our findings suggested that C118P inhibits GC growth by promoting the autophagy-lysosomal-dependent degradation of RAB1A and modulating mTOR C1 signaling. C118P shows potential as being a small molecule drug effective in the treatment of gastric cancer via targeting RAB1A.

Concurrent preoperative eribulin and radiation for resectable retroperitoneal liposarcoma: a phase 1B study.

Management of retroperitoneal liposarcoma (RPLPS) is challenging and recurrence rates remain high despite aggressive surgical resections. Preoperative radiation alone lacks definitive benefit, thus we sought to evaluate combined chemoradiotherapy with the potential to enhance local efficacy of radiation as well as control micrometastatic disease. We assessed the safety and tolerability of preoperative eribulin, a cytotoxic microtubule inhibitor approved for the treatment of advanced liposarcoma, in combination with radiation in patients with RPLPS. In this open-label dose-finding study, patients with primary or recurrent resectable RPLPS received preoperative intensity-modulated radiation therapy (IMRT) with escalating doses of eribulin. Eribulin was administered for three 21-day cycles at a starting dose of 1.1 mg/m2. Concurrent radiation to 50.4 Gy began during cycle 1. Surgical resection occurred 3-10 weeks after completion of chemoradiation. The primary endpoint was determination of the recommended phase 2 doses (RP2D) of concurrent eribulin and radiation. Between 2018-2023, fifteen patients were enrolled. Thirteen patients were evaluable for dose-determination. Four patients treated at starting dose level had no dose-limiting toxicities (DLTs). Two of nine patients treated with escalated eribulin dose had DLTs. The RP2D was established as eribulin 1.4 mg/m2 and IMRT 50.4 Gy. Eleven patients were evaluable for secondary efficacy endpoints. The median recurrence-free survival was 30.4 months (95% CI 12.0-NR) and the median overall survival was 54.1 months (95% CI 9.5-NR). Patient reported outcome data did not show any significant changes over the study period. A preoperative chemoradiation protocol of eribulin in combination with IMRT showed a manageable safety profile and warrants additional prospective evaluation for treatment of resectable RPLPS.

Plant growth Enhancement in Colchicine-Treated Tomato Seeds without Polyploidy Induction

Plant breeding plays a pivotal role in the development of improved tomato cultivars, addressing various challenges faced by this crop worldwide. Tomato crop yield is affected by biotic and abiotic stress, including diverse pathogens and pests, extreme temperatures, drought, and soil salinity, thus affecting fruit quality, and overall crop productivity. Through strategic plant breeding approaches, it is possible to increase the genetic diversity of tomato cultivars, leading to the development of varieties with increased resistance to prevalent diseases and pests, improved tolerance to environmental stress, and enhanced adaptability to changing agroclimatic conditions. The induction of genetic variability using antimitotic agents, such as colchicine, has been widely employed in plant breeding precisely to this end. In this study, we analyzed the transcriptome of colchicine-treated tomato plants exhibiting larger size, characterized by larger leaves, while seedlings of the T2 generation harbored three cotyledons. A total of 382 differentially expressed genes encoding proteins associated with anatomical structure development, hormone synthesis and transport, flavonoid biosynthesis, and responses to various stimuli, stresses, and defense mechanisms were identified. Gene enrichment analysis suggests a role for auxin and flavonoid biosynthesis in cotyledon formation. Furthermore, single-nucleotide polymorphisms were mapped in colchicine-treated plants and determined which corresponded to differentially- expressed genes. Interestingly, most were associated to only a few genes in a similar location. This study provides significant insights into the genes and metabolic pathways affected in colchicine-treated tomatoes that exhibit improved agronomic traits, such as plant vigor and improved photosynthesis rate.

Abstract A019: Discovery of a potent and brain-penetrable tubulin inhibitor SB-216 that shows efficacy in primary tumor growth and brain metastasis

Abstract A major clinical challenge in cancer treatment is to prevent and treat metastatic disease. Despite the significant advancements in targeted therapy and immunotherapy, chemotherapeutic drugs, including taxanes, remain one of the mainline systemic treatment options for several major cancer types. However, the prolonged use of taxanes has been associated with the development of multidrug resistance, dose-limiting hematopoietic toxicity, and neurotoxicity, frequently presenting as persistent peripheral neuropathy. In addition, these drugs have limited blood-brain barrier penetration, and thus they are not effective in treating brain tumors or brain metastases from other cancer types, particularly breast cancer metastases. We have developed a new generation of tubulin inhibitors, termed colchicine binding site inhibitors (CBSIs). Unlike taxanes, these compounds bind to the colchicine site in tubulin, structurally less complex than taxanes which enables fine-tuning of physical-chemical properties, and shows the ability to overcome acquired drug resistance to existing taxane drugs. One of the best inhibitors in this class of compounds is SB-216. We have solved the high-resolution crystal structure of SB-216 in a complex with tubulin protein (PDB: 6X1F) and confirmed its mode of action. Extensive preclinical evaluations of SB-216 in a number of tumor models, including taxane-resistant prostate cancer, melanoma, ovarian cancer, and triple-negative breast cancer, indicated that SB-216 is highly potent in suppressing both primary tumor growth and tumor metastases. Importantly, SB-216 shows high brain penetration and shows efficacy in suppressing brain metastases from triple-negative breast cancer. SB-216 also has good drug-like properties and shows strong promise as a new generation of tubulin inhibitor for systemic cancer treatments, not only in brain metastasis from non-CNS tumors but also potentially be useful for brain tumors such as glioma. The work is supported by NIH/NCI grants R01CA14876 and R01CA276152 and the DoD grant HT9425-23-1-0216. Citation Format: Kelli L. Adeleye, Satyanarayana Pochampally, Raisa Krutilina, Rui Wang, Junming Yue, Tiffany Seagroves, Duane D.Miller, Wei Li. Discovery of a potent and brain-penetrable tubulin inhibitor SB-216 that shows efficacy in primary tumor growth and brain metastasis [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Optimizing Therapeutic Efficacy and Tolerability through Cancer Chemistry; 2024 Dec 9-11; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(12_Suppl):Abstract nr A019.

Nuclei as mechanical bumpers during epithelial remodeling.

The morphogenesis of developing tissues relies on extensive cellular rearrangements in shape, position, and identity. A key process in reshaping tissues is cell intercalation-driven elongation, where epithelial cells align and intercalate along a common axis. Typically, analyses focus on how peripheral cortical forces influence cell shape changes. Less attention is given to how inhomogeneities in internal structures, particularly the nucleus, impact cell shaping. Here, we examine how pulsed contractile and extension dynamics interact with the nucleus in elongating Drosophila embryos. Our data show that tightly packed nuclei in apical layers hinder tissue remodeling/oscillatory behaviors. We identify two mechanisms for resolving internuclear tensions: nuclear deformation and dispersion. Embryos with non-deformable nuclei use nuclear dispersion to maintain near-normal extensile rates, while those with non-dispersible nuclei due to microtubule inhibition exhibit disruptions in contractile behaviors. Disrupting both mechanisms leads to severe tissue extension defects and cell extrusion. These findings highlight the critical role of nuclear shape and positioning in topological remodeling of epithelia.

Identification of antimitotic sulfonamides inhibiting chromosome congression.

The discovery of new small-molecule inhibitors is essential to enhancing our understanding of biological events at the molecular level and driving advancements in drug discovery. Mitotic inhibitors have played a crucial role in development of anticancer drugs. Beyond traditional microtubule inhibitors, various inhibitors targeting specific mitotic factors have been developed. This study aimed to develop novel mitotic inhibitors targeting chromosome alignment. We established a cell-based screening method using Cell Division Cycle Associated 5 (CDCA5) and kinesin-5 as markers, designed to efficiently detect mitotic phenotypes characterized by aberrant bipolar spindles with some misaligned chromosomes. Through this screening, we identified CAIS-1, an aryl sulfonamide with unique antimitotic properties. CAIS-1 exhibits dual functionality by inhibiting chromosome congression at low concentrations and spindle microtubule formation at high concentrations, causing a concentration-dependent mitotic arrest, followed by apoptotic cell death. Mechanistic studies revealed that CAIS-1 directly acts on tubulin at high concentrations, thereby inhibiting tubulin polymerization in vitro. In contrast, at low concentrations, CAIS-1 functions through a mechanism distinct from GSK923295, a conventional chromosome congression inhibitor targeting Centromere-associated protein-E (CENP-E), highlighting its unique mode of action. Moreover, CAIS-2, a structural analog of CAIS-1, selectively inhibits chromosome congression without significantly affecting spindle microtubules. This observation suggests that CAIS-1 and CAIS-2 function as antimitotic sulfonamides with distinct targets beyond tubulin, thus offering additional biological potential of sulfonamide compounds. Together, CAIS-1 and CAIS-2 represent promising tools for providing new molecular insights into kinetochore function during mitosis and for exploring new approaches in anticancer drug development.