Bcl-2 blocks cisplatin-induced apoptosis and predicts poor outcome following chemoradiation treatment in advanced oropharyngeal squamous cell carcinoma

Groenlandicine enhances cisplatin sensitivity in cisplatin-resistant osteosarcoma cells through the BAX/Bcl-2/Caspase-9/Caspase-3 pathway

Groenlandicine is a protoberberine alkaloid isolated from Coptidis Rhizoma, a widely used traditional Chinese medicine known for its various biological activities. This study aims to validate groenlandicine's effect on both cisplatin-sensitive and cisplatin-resistant osteosarcoma (OS) cells, along with exploring its potential molecular mechanism. The ligand-based virtual screening (LBVS) method and molecular docking were employed to screen drugs. CCK-8 and FCM were used to measure the effect of groenlandicine on the OS cells transfected by lentivirus with over-expression or low-expression of TOP1. Cell scratch assay, CCK-8, FCM, and the EdU assay were utilized to evaluate the effect of groenlandicine on cisplatin-resistant cells. WB, immunofluorescence, and PCR were conducted to measure the levels of TOP1, Bcl-2, BAX, Caspase-9, and Caspase-3. Additionally, a subcutaneous tumor model was established in nude mice to verify the efficacy of groenlandicine. Groenlandicine reduced the migration and proliferation while promoting apoptosis in OS cells, effectively damaging them. Meanwhile, groenlandicine exhibited weak cytotoxicity in 293T cells. Combination with cisplatin enhanced tumor-killing activity, markedly activating BAX, cleaved-Caspase-3, and cleaved-Caspase-9, while inhibiting the Bcl2 pathway in cisplatin-resistant OS cells. Moreover, the level of TOP1, elevated in cisplatin-resistant OS cells, was down-regulated by groenlandicine both in vitro and in vivo. Animal experiments confirmed that groenlandicine combined with cisplatin suppressed OS growth with lower nephrotoxicity. Groenlandicine induces apoptosis and enhances the sensitivity of drug-resistant OS cells to cisplatin via the BAX/Bcl-2/Caspase-9/Caspase-3 pathway. Groenlandicine inhibits OS cells growth by down-regulating TOP1 level.Therefore, groenlandicine holds promise as a potential agent for reversing cisplatin resistance in OS treatment.

Evasion of apoptosis and treatment resistance in squamous cell carcinoma of the head and neck

Combinations of surgery, radiotherapy and chemotherapy can eradicate tumors in patients with locally advanced squamous cell carcinoma of the head and neck (LA SCCHN), but a significant proportion of tumors progress, recur, or do not respond to therapy due to treatment resistance. The prognosis for these patients is poor, thus new approaches are needed to improve outcomes. Key resistance mechanisms to chemoradiotherapy (CRT) in patients with LA SCCHN are alterations to the pathways that mediate apoptosis, a form of programmed cell death. Targeting dysregulation of apoptotic pathways represents a rational therapeutic strategy in many types of cancer, with a number of proteins, including the pro-survival B-cell lymphoma 2 family and inhibitors of apoptosis proteins (IAPs), having been identified as druggable targets. This review discusses the mechanisms by which apoptosis occurs under physiological conditions, and how this process is abnormally restrained in LA SCCHN tumor cells, with treatment strategies aimed at re-enabling apoptosis in LA SCCHN also considered. In particular, the development of, and future opportunities for, IAP inhibitors in LA SCCHN are discussed, in light of recent encouraging proof-of-concept clinical trial data.

Comprehensive review of Bcl-2 family proteins in cancer apoptosis: Therapeutic strategies and promising updates of natural bioactive compounds and small molecules

Cancer has a considerably higher fatality rate than other diseases globally and is one of the most lethal and profoundly disruptive ailments. The increasing incidence of cancer among humans is one of the greatest challenges in the field of healthcare. A significant factor in the initiation and progression of tumorigenesis is the dysregulation of physiological processes governing cell death, which results in the survival of cancerous cells. B-cell lymphoma 2 (Bcl-2) family members play important roles in several cancer-related processes. Drug research and development have identified various promising natural compounds that demonstrate potent anticancer effects by specifically targeting Bcl-2 family proteins and their associated signaling pathways. This comprehensive review highlights the substantial roles of Bcl-2 family proteins in regulating apoptosis, including the intricate signaling pathways governing the activity of these proteins, the impact of reactive oxygen species, and the crucial involvement of proteasome degradation and the stress response. Furthermore, this review discusses advances in the exploration and potential therapeutic applications of natural compounds and small molecules targeting Bcl-2 family proteins and thus provides substantial scientific information and therapeutic strategies for cancer management.

Novel NF-κB Inhibitor-Conjugated Pt(IV) Prodrug to Enable Cancer Therapy through ROS/ER Stress and Mitochondrial Dysfunction and Overcome Multidrug Resistance

Although cisplatin has been widely used for clinical purposes, its application is limited due to its obvious side effects. To mitigate the defects of cisplatin, here, six "multitarget prodrugs" were synthesized by linking cisplatin and NF-κB inhibitors. Notably, complex 9 demonstrated a 63-fold enhancement in the activity against A549/CDDP cells with lower toxicity toward normal LO2 cells compared to cisplatin. Additionally, complex 9 could effectively cause DNA damage, induce mitochondrial dysfunction, generate reactive oxygen species, and induce cell apoptosis through the mitochondrial pathway and ER stress. Remarkably, complex 9 effectively inhibited the NF-κB/MAPK signaling pathway and disrupted the PI3K/AKT signaling transduction. Importantly, complex 9 showed superior in vivo antitumor efficiency compared to cisplatin or the combination of cisplatin/4, without obvious systemic toxicity in A549 or A549/CDDP xenograft models. Our results demonstrated that the dual-acting mechanism endowed the complexes with high efficiency and low toxicity, which may represent an efficient strategy for cancer therapy.

Curcumin inhibits the growth and invasion of gastric cancer by regulating long noncoding RNA AC022424.2

BACKGROUND

Gastric cancer, characterized by a multifactorial etiology and high heterogeneity, continues to confound researchers in terms of its pathogenesis. Curcumin, a natural anticancer agent, exhibits therapeutic promise in gastric cancer. Its effects include promoting cell apoptosis, curtailing tumor angiogenesis, and enhancing sensitivity to radiation and chemotherapy. Long noncoding RNAs (lncRNAs) have garnered significant attention as biomarkers for early screening, diagnosis, treatment, and drug response because of their remarkable specificity and sensitivity. Recent investigations have revealed an association between aberrant lncRNA expression and early diagnosis, clinical staging, metastasis, drug sensitivity, and prognosis in gastric cancer. A profound understanding of the intricate mechanisms through which lncRNAs influence gastric cancer development can provide novel insights for precision treatment and tailored management of patients with gastric cancer. This study aimed to unravel the potential of curcumin in suppressing the malignant behavior of gastric cancer cells by upregulating specific lncRNAs and modulating gastric cancer onset and progression.

AIM

To identify lncRNAs associated with curcumin treatment and investigate the role of lncRNA AC022424.2 in the effects of curcumin on gastric cancer cell apoptosis, proliferation, and invasion. Furthermore, these findings were validated in clinical samples.

METHODS

The study employed CCK-8 assays to assess the impact of curcumin on gastric cancer cell proliferation, flow cytometry to investigate its effects on apoptosis, and scratch and Transwell assays to evaluate its influence on the migration and invasion of BGC-823 and MGC-803 cells. Western blotting was used to gauge changes in the protein expression levels of CDK6, CDK4, Bax, Bcl-2, caspase-3, P65, and the PI3K/Akt/mTOR pathway in gastric cancer cell lines after curcumin treatment. Differential expression of lncRNAs before and after curcumin treatment was assessed using lncRNA sequencing and validated using quantitative reverse transcription polymerase chain reaction (qRT-PCR) in BGC-823 and MGC-803 cells. AC022424.2-1 knockdown BGC-823 and MGC-803 cells were generated to scrutinize the impact of lncRNA AC022424.2 on apoptosis, proliferation, migration, and invasion of gastric cancer cells. Western blotting was performed to ascertain changes in the expression of proteins implicated in the PI3K/Akt/mTOR and NF-κB signaling pathways. RT-PCR was employed to measure lncRNA AC022424.2 expression in clinical gastric cancer tissues and to correlate its expression with clinical pathological characteristics.

RESULTS

Curcumin induced apoptosis and hindered proliferation, migration, and invasion of gastric cancer cells in a dose- and time-dependent manner. LncRNA AC022424.2 was upregulated after curcumin treatment, and its knockdown enhanced cancer cell aggressiveness. LncRNA AC022424.2 may have affected cancer cells via the PI3K/Akt/mTOR and NF-κB signaling pathways. LncRNA AC022424.2 downregulation was correlated with lymph node metastasis, making it a potential diagnostic and prognostic marker.

CONCLUSION

Curcumin has potential anticancer effects on gastric cancer cells by regulating lncRNA AC022424.2. This lncRNA plays a significant role in cancer cell behavior and may have clinical implications in diagnosis and prognosis evaluation. The results of this study enhance our understanding of gastric cancer development and precision treatment.

Supramolecular nanodrug targeting CDK4/6 overcomes BAG1 mediated cisplatin resistance in oral squamous cell carcinoma

Chemoresistance to cisplatin remains a significant challenge affecting the prognosis of advanced oral squamous cell carcinoma (OSCC). However, the specific biomarkers and underlying mechanisms responsible for cisplatin resistance remain elusive. Through comprehensive bioinformatic analyses, we identified a potential biomarker, BCL2 associated athanogene-1 (BAG1), showing elevated expression in head and neck squamous cell carcinoma (HNSCC). Since OSCC represents the primary pathological type of HNSCC, we investigated BAG1 expression in human tumor tissues and cisplatin resistant OSCC cell lines, revealing that silencing BAG1 induced apoptosis in cisplatin-resistant cells both in vitro and in vivo. This effect led to impaired cell viability of cisplatin resistant OSCC cells and indicated a positive correlation between BAG1 expression and the G1/S transition during cell proliferation. Based on these insights, the administration of a CDK4/6 inhibitor in combination with cisplatin effectively overcame cisplatin resistance in OSCC through the CDK4/6-BAG1 axis. Additionally, to enable simultaneous drug delivery and enhance synergistic antitumor efficacy, we developed a novel supramolecular nanodrug LEE011-FFERGD/CDDP, which was validated in an OSCC orthotopic mouse model. In summary, our study highlights the potential of a combined administration of CDK4/6 inhibitor and cisplatin as a promising therapeutic regimen for treating advanced or cisplatin resistant OSCC.

Current and Emerging Diagnostic, Prognostic, and Predictive Biomarkers in Head and Neck Cancer

Head and neck cancers (HNC) are a biologically diverse set of cancers that are responsible for over 660,000 new diagnoses each year. Current therapies for HNC require a comprehensive, multimodal approach encompassing resection, radiation therapy, and systemic therapy. With an increased understanding of the mechanisms behind HNC, there has been growing interest in more accurate prognostic indicators of disease, effective post-treatment surveillance, and individualized treatments. This chapter will highlight the commonly used and studied biomarkers in head and neck squamous cell carcinoma.

SETD8, a frequently mutated gene in cervical cancer, enhances cisplatin sensitivity by impairing DNA repair

BACKGROUND

Cisplatin is commonly used to treat cervical cancer while drug resistance limits its effectiveness. There is an urgent need to identify strategies that increase cisplatin sensitivity and improve the outcomes of chemotherapy.

RESULTS

We performed whole exome sequencing (WES) of 156 cervical cancer tissues to assess genomic features related to platinum-based chemoresistance. By using WES, we identified a frequently mutated locus SETD8 (7%), which was associated with drug sensitivity. Cell functional assays, in vivo xenografts tumor growth experiments, and survival analysis were used to investigate the functional significance and mechanism of chemosensitization after SETD8 downregulation. Knockdown of SETD8 increased the responsiveness of cervical cancer cells to cisplatin treatment. The mechanism is exerted by reduced binding of 53BP1 to DNA breaks and inhibition of the non-homologous end joining (NHEJ) repair pathway. In addition, SETD8 expression was positively correlated with resistance to cisplatin and negatively associated with the prognosis of cervical cancer patients. Further, UNC0379 as a small molecule inhibitor of SETD8 was found to enhance cisplatin sensitivity both in vitro and in vivo.

CONCLUSIONS

SETD8 was a promising therapeutic target to ameliorate cisplatin resistance and improve the efficacy of chemotherapy.

Correlation of Bcl-2 Expression with Prognosis and Survival in Patients with Head and Neck Cancer: A Systematic Review and Meta-Analysis

Head and neck cancer (HNC) is a growing disease, affecting more than 700.000 cases per year and ranking as the sixth most prevalent type of cancer worldwide. The impossibility of properly entering into apoptosis directly influences uncontrolled growth and consequently tumor development and progression. Bcl-2 emerged as a key regulator in the balance between cell apoptosis and proliferation in apoptosis machinery. This systematic review and meta-analysis aimed to review all published studies investigating changes in Bcl-2 protein expression assessed by immunohistochemistry (IHC) and related to prognostic and survival values of patients with HNC. After applying the inclusion and exclusion factors, we reached the number of 20 articles included in the meta-analysis. The random-effect pooled HR (CI95%) value of OS related to Bcl-2 IHC expression in tissues from HNC patients was 1.80 (CI95% 1.21-2.67) (p < 0.0001) and DFS was 1.90 (CI95% 1.26-2.86 (p < 0.0001). The OS value for the specific oral cavity tumors was 1.89 (1.34-2.67), while in the larynx it was 1.77 (0.62-5.06), and the DFS in the pharynx was 2.02 (1.46-2.79). The univariate and multivariate analyses of OS were respectively 1.43 (1.11-1.86) and 1.88 (1.12-3.16), while in DFS it was 1.70 (0.95-3.03) and 2.08 (1.55-2.80). The OS considering a low cut-off for Bcl-2 positivity was 1.19 (0.60-2.37) and DFS was 1.48 (0.91-2.41), while studies with a high cut-off demonstrated OS of 2.28 (1.47-3.52) and DFS of 2.77 (1.74-4.40). Our meta-analysis demonstrates that Bcl-2 protein overexpression can result in worse LNM, OS, and DFS in patients with HNC, however, it is not a reliable conclusion, due to the wide divergences between the original studies and the fact that many studies have a very high range of confidence and also a high risk of bias.

Genetic polymorphisms in genes regulating cell death and prognosis of patients with rectal cancer receiving postoperative chemoradiotherapy

OBJECTIVE

The identification of biomarkers for predicting chemoradiotherapy efficacy is essential to optimize personalized treatment. This study determined the effects of genetic variations in genes involved in apoptosis, pyroptosis, and ferroptosis on the prognosis of patients with locally advanced rectal cancer receiving postoperative chemoradiotherapy (CRT).

METHODS

The Sequenom MassARRAY was used to detect 217 genetic variations in 40 genes from 300 patients with rectal cancer who received postoperative CRT. The associations between genetic variations and overall survival (OS) were evaluated using hazard ratios (HRs) and 95% confidence intervals (CIs) computed using a Cox proportional regression model. Functional experiments were performed to determine the functions of the arachidonate 5-lipoxygenase (ALOX5) gene and the ALOX5 rs702365 variant.

RESULTS

We detected 16 genetic polymorphisms in CASP3, CASP7, TRAILR2, GSDME, CASP4, HO-1, ALOX5, GPX4, and NRF2 that were significantly associated with OS in the additive model (P < 0.05). There was a substantial cumulative effect of three genetic polymorphisms (CASP4 rs571407, ALOX5 rs2242332, and HO-1 rs17883419) on OS. Genetic variations in the CASP4 and ALOX5 gene haplotypes were associated with a higher OS. We demonstrated, for the first time, that rs702365 [G] > [C] represses ALOX5 transcription and corollary experiments suggested that ALOX5 may promote colon cancer cell growth by mediating an inflammatory response.

CONCLUSIONS

Polymorphisms in genes regulating cell death may play essential roles in the prognosis of patients with rectal cancer who are treated with postoperative CRT and may serve as potential genetic biomarkers for individualized treatment.

Elevated N-Glycosylation Contributes to the Cisplatin Resistance of Non-Small Cell Lung Cancer Cells Revealed by Membrane Proteomic and Glycoproteomic Analysis

Chemoresistance is the major restriction on the clinical use of cisplatin. Aberrant changes in protein glycosylation are closely associated with drug resistance. Comprehensive study on the role of protein glycosylation in the development of cisplatin resistance would contribute to precise elucidation of the complicated mechanism of resistance. However, comprehensive characterization of glycosylated proteins remains a big challenge. In this work, we integrated proteomic and N-glycoproteomic workflow to comprehensively characterize the cisplatin resistance-related membrane proteins. Using this method, we found that proteins implicated in cell adhesion, migration, response to drug, and signal transduction were significantly altered in both protein abundance and glycosylation level during the development of cisplatin resistance in the non-small cell lung cancer cell line. Accordingly, the ability of cell migration and invasion was markedly increased in cisplatin-resistant cells, hence intensifying their malignancy. In contrast, the intracellular cisplatin accumulation was significantly reduced in the resistant cells concomitant with the down-regulation of drug uptake channel protein, LRRC8A, and over-expression of drug efflux pump proteins, MRP1 and MRP4. Moreover, the global glycosylation was elevated in the cisplatin-resistant cells. Consequently, inhibition of N-glycosylation reduced cell resistance to cisplatin, whereas promoting the high-mannose or sialylated type of glycosylation enhanced the resistance, suggesting that critical glycosylation type contributes to cisplatin resistance. These results demonstrate the high efficiency of the integrated proteomic and N-glycoproteomic workflow in discovering drug resistance-related targets, and provide new insights into the mechanism of cisplatin resistance.

RSL3 enhances the antitumor effect of cisplatin on prostate cancer cells via causing glycolysis dysfunction

The resistance to cisplatin (DDP) and dose-related toxicity are the two important obstacles in the chemotherapy of prostate cancer (PCa) patients. The present study demonstrated that cotreatment of DDP and RSL3, a type of small molecular compound which can inactivate glutathione peroxidase 4 (GPX4) and induce ferroptosis, synergistically inhibited the viability and proliferation of PCa cells in vitro and in vivo at low dose. In vitro studies revealed that RSL3 improved that sensitivity of PCa cells to DDP by producing ROS and aggravating the cell cycle arrest and apoptosis caused by DDP. Mechanistically, RSL3 could decrease the ATP and pyruvate content as well as the protein levels of HKII, PFKP, PKM2, which indicated that RSL3 induced glycolysis dysfunction in prostate cancer cells. Rescuing RSL3-induced glycolysis dysfunction by supplement of exterior sodium pyruvate not only inhibited RSL3/DDP-induced changes of apoptosis-related proteins levels, but also mitigated the cell death caused by RSL3/DDP. In vivo studies further confirmed that cotreatment of RSL3 and DDP at low dose significantly inhibited the growth of PCa with no obvious side effects. Taken together, we demonstrated that RSL3 improved the sensitivity of PCa to DDP via causing glycolysis dysfunction. Our findings indicated that DDP-based chemotherapy combined with RSL3 might provide a promising therapy for PCa.

Association between Cone-Beam Computed Tomography and Histological and Immunohistochemical Features in Periapical Lesions Correlated with Thickened Maxillary Sinus Mucosa

Background and Objectives: Odontogenic sinusitis is a frequently underestimated pathology with fewer symptoms in patients with periapical lesions, periodontal disease, or iatrogenic foreign bodies in the maxillary sinus. The aim of our study was to determine the correlation between maxillary sinusitis and periapical lesions using cone-beam computed tomography (CBCT) imaging and histological and immunohistochemical investigations. Materials and Methods: A total of 1450 initial patients diagnosed with maxillary sinusitis in the Ear-Nose-Throat (ENT) Department, University of Medicine and Pharmacy “Grigore T. Popa” Iasi, Romania, were treated with anti-inflammatory drugs. Of these, 629 still had unresolved symptomatology and were later referred to the Dental Medicine departments for further investigations. Only 50 subjects with periapical lesions in the premolar/molar maxillary area were included in the present study. All the periapical lesions were observed on CBCT and classified using the Periapical Status Index (PSI) and the mean maxillary sinus mucosa thicknesses (MSMT). The enrolled patients underwent surgical procedures with the excision of periapical lesions. The excised samples were submitted to the histological and immunohistochemical investigations. Results: The 50 patients presented periapical lesions of their maxillary teeth in 328 dental units. There was a higher prevalence of periapical lesions in men than in women (chi-square test). We observed a significant difference between the mean MSMT of individuals with periapical lesions compared to those without (p < 0.01). Mean MSMT was 1.23 mm for teeth without periapical lesions and 3.95 mm for teeth with periapical lesions. The histopathological study identified 50% cases with periapical granulomas, 10% cases with periapical granulomas with cystic potential, and 40% cases as periapical cysts. Immunohistochemical stainings showed that CD4+ helper and CD8+ cytotoxic T lymphocytes, along with CD20+ B lymphocytes and CD68+ macrophages, were diffusely distributed in all periapical cysts and in some periapical granulomas, but CD79α+ plasma cells characterized especially periapical granulomas. Conclusions: The current study observed a significant correlation between CBCT maxillary mucosa thickness and type of periapical lesion. Chronic inflammatory lympho-histiocytic infiltrate predominates in periapical lesions, supporting the idea that lesion progression is determined by a humoral-type (CD20+ and CD79α+ B lymphocytes) but also by a cellular-type (CD4+ and CD8+ T lymphocyte population) immune mechanism.

Targeting Bcl-2 for cancer therapy

Apoptosis deficiency is one of the most important features observed in neoplastic diseases. The Bcl-2 family is composed of a subset of proteins that act as decisive apoptosis regulators. Research and clinical studies have both demonstrated that the hyperactivation of Bcl-2-related anti-apoptotic effects correlates with cancer occurrence, progression and prognosis, also having a role in facilitating the radio- and chemoresistance of various malignancies. Therefore, targeting Bcl-2 inactivation has provided some compelling therapeutic advantages by enhancing apoptotic sensitivity or reversing drug resistance. Therefore, this pharmacological route turned into one of the most promising routes for cancer treatment. This review discusses some of the well-defined and emerging roles of Bcl-2 as well as its potential clinical value in cancer therapeutics.

Mitochondria: The metabolic switch of cellular oncogenic transformation

Mitochondria, well recognized as the "powerhouse" of cells, are maternally inherited organelles with bacterial ancestry that play essential roles in a myriad of cellular functions. It has become profoundly evident that mitochondria regulate a wide array of cellular and metabolic functions, including biosynthetic metabolism, cell signaling, redox homeostasis, and cell survival. Correspondingly, defects in normal mitochondrial functioning have been implicated in various human malignancies. Cancer development involves the activation of oncogenes, inactivation of tumor suppressor genes, and impairment of apoptotic programs in cells. Mitochondria have been recognized as the site of key metabolic switches for normal cells to acquire a malignant phenotype. This review outlines the role of mitochondria in human malignancies and highlights potential aspects of mitochondrial metabolism that could be targeted for therapeutic development.

Natural products as a means of overcoming cisplatin chemoresistance in bladder cancer

Cisplatin remains an integral part of the treatment for muscle invasive bladder cancer. A large number of patients do not respond to cisplatin-based chemotherapy and efficacious salvage regimens are limited. Immunotherapy has offered a second line of treatment; however, only approximately 20% of patients respond, and molecular subtyping of tumors indicates there may be significant overlap in those patients that respond to cisplatin and those patients that respond to immunotherapy. As such, restoring sensitivity to cisplatin remains a major hurdle to improving patient care. One potential source of compounds for enhancing cisplatin is naturally derived bioactive products such as phytochemicals, flavonoids and others. These compounds can activate a diverse array of different pathways, many of which can directly promote or inhibit cisplatin sensitivity. The purpose of this review is to understand current drug development in the area of natural products and to assess how these compounds may enhance cisplatin treatment in bladder cancer patients.

Precision Medicine Approaches to Overcome Resistance to Therapy in Head and Neck Cancers

Head and neck squamous cell carcinoma (HNSCC) is the sixth most incident cancer worldwide. More than half of HNSCC patients experience locoregional or distant relapse to treatment despite aggressive multimodal therapeutic approaches that include surgical resection, radiation therapy, and adjuvant chemotherapy. Before the arrival of immunotherapy, systemic chemotherapy was previously employed as the standard first-line protocol with an association of cisplatin or carboplatin plus 5-fluorouracil plus cetuximab (anti-EFGR antibody). Unfortunately, acquisition of therapy resistance is common in patients with HNSCC and often results in local and distant failure. Despite our better understanding of HNSCC biology, no other molecular-targeted agent has been approved for HNSCC. In this review, we outline the mechanisms of resistance to the therapeutic strategies currently used in HNSCC, discuss combination treatment strategies to overcome them, and summarize the therapeutic regimens that are presently being evaluated in early- and late-phase clinical trials.

Ru(II)-Based Amino Acid Complexes Show Promise for Leukemia Treatment: Cytotoxicity and Some Light on their Mechanism of Action

Ruthenium is attracting considerable interest as the basis for new compounds to treat diseases, and studies have shown that complexes with different structures have significant antineoplastic and antimetastatic potential against several types of tumors, including tumors resistant to cisplatin drugs. We examined the cytotoxic, genotoxic, and pro-apoptotic activities of six ruthenium complexes containing amino acid with general formulation [Ru(AA)(bipy)(dppb)]PF₆, where AA = amino acid (alanine, glycine, leucine, lysine, methionine, or tryptophan); bipy = 2,2´-bipyridine; and dppb = [1,4-bis(diphenylphosphine)butane], against A549 (lung carcinoma) and K562 (chronic myelogenous leukemia) cancer cells. The results show that the ruthenium complexes tested were able to induce cytotoxicity in A549 and K562 cancer cells. Complex 1 containing alanine inhibited the cell viability of A549 and K562 tumor cells by inducing apoptosis, as evidenced by an increased number of Annexin V-positive cells and the induction of DNA damage and cell cycle arrest. Complex 1 was able to induce caspase-mediated apoptosis in K562 cells through the mitochondrial dysfunction, the upregulation of apoptotic genes, and the downregulation of Bcl2 anti-apoptotic gene. Besides being cytotoxic to K562 and A549 cells, ruthenium complex containing alanine shows low cytotoxicity and genotoxicity against non-tumor cells. These results suggest that the ruthenium (II) complex is a potential safe and efficient antineoplastic candidate for leukemia treatment.

Cisplatin Resistance in Testicular Germ Cell Tumors: Current Challenges from Various Perspectives

Testicular germ cell tumors share a marked sensitivity to cisplatin, contributing to their overall good prognosis. However, a subset of patients develop resistance to platinum-based treatments, by still-elusive mechanisms, experiencing poor quality of life due to multiple (often ineffective) interventions and, eventually, dying from disease. Currently, there is a lack of defined treatment opportunities for these patients that tackle the mechanism(s) underlying the emergence of resistance. Herein, we aim to provide a multifaceted overview of cisplatin resistance in testicular germ cell tumors, from the clinical perspective, to the pathobiology (including mechanisms contributing to induction of the resistant phenotype), to experimental models available for studying this occurrence. We provide a systematic summary of pre-target, on-target, post-target, and off-target mechanisms putatively involved in cisplatin resistance, providing data from preclinical studies and from those attempting validation in clinical samples, including those exploring specific alterations as therapeutic targets, some of them included in ongoing clinical trials. We briefly discuss the specificities of resistance related to teratoma (differentiated) phenotype, including the phenomena of growing teratoma syndrome and development of somatic-type malignancy. Cisplatin resistance is most likely multifactorial, and a combination of therapeutic strategies will most likely produce the best clinical benefit.

Gefitinib sensitization of cisplatin-resistant wild-type EGFR non-small cell lung cancer cells

Purpose

The usual first-line strategy of wild-type EGFR (wtEGFR) non-small cell lung cancer (NSCLC) remains cisplatin-based chemotherapy. However, cisplatin often loses effectiveness because most tumors acquire drug resistance over time. As EGFR is the most important pro-survival/proliferation signal receptor in NSCLC cells, we aimed at investigating whether cisplatin resistance is related to EGFR activation and further evaluating the combined effects of cisplatin/gefitinib (EGFR-tyrosine kinase inhibitor, EGFR-TKI) on cisplatin-resistant wtEGFR NSCLC cells.

Materials and methods

EGFR activation was analysed in parental and cisplatin-resistant wtEGFR NSCLC cell lines (H358 and H358^R, A549 and A549^R). Cellular proliferation and apoptosis of H358^R/A549^R cells treated with cisplatin or gefitinib, alone or in combination were investigated, and the related effector protein was detected by western blot analysis. Anti-tumor effect of two drugs combined was evaluated in animal models of H358^R xenografts in vivo.

Results

EGFR was significantly phosphorylated in cisplatin-resistant wtEGFR NSCLC cells H358^R and A549^R than their parental cells. In H358^R and A549^R cells, anti-proliferative ability of gefitinib was further improved, and gefitinib combined with cisplatin enhanced inhibition of cellular survive/proliferation, and promotion of apoptosis in vitro. The combined effects were also associated with the inhibition of EGFR downstream effector proteins. Similarly, in vivo, gefitinib and cisplatin in combination significantly inhibited tumor growth of H358^R xenografts.

Conclusion

Abnormal activation of EGFR may induce wtEGFR NSCLC cell resistance to cisplatin. The combined effects of cisplatin/gefitinib suggest that gefitinib, as a combination therapy for patients with cisplatin-resistant wtEGFR NSCLC should be considered.

Links between cancer metabolism and cisplatin resistance

Cisplatin is one of the most potent and widely used chemotherapeutic agent in the treatment of several solid tumors, despite the high toxicity and the frequent relapse of patients due to the onset of drug resistance. Resistance to chemotherapeutic agents, either intrinsic or acquired, is currently one of the major problems in oncology. Thus, understanding the biology of chemoresistance is fundamental in order to overcome this challenge and to improve the survival rate of patients. Studies over the last 30 decades have underlined how resistance is a multifactorial phenomenon not yet completely understood. Recently, tumor metabolism has gained a lot of interest in the context of chemoresistance; accumulating evidence suggests that the rearrangements of the principal metabolic pathways within cells, contributes to the sensitivity of tumor to the drug treatment. In this review, the principal metabolic alterations associated with cisplatin resistance are highlighted. Improving the knowledge of the influence of metabolism on cisplatin response is fundamental to identify new possible metabolic targets useful for combinatory treatments, in order to overcome cisplatin resistance.

Apoptosis signaling molecules as treatment targets in head and neck squamous cell carcinoma

OBJECTIVES

To evaluate BCL-2 family signaling molecules in head and neck squamous cell carcinoma (HNSCC) and examine the ability of therapeutic agents with variable mechanisms of action to induce apoptosis in HNSCC cells.

METHODS

messenger ribonculeic acid (mRNA) expression of BAK, BAX, B-cell lymphoma (Bcl-2), BCL2 Like 1 (BCL2L1), and MCL1 were measured in The Cancer Genome Atlas (TCGA) head and neck cancer dataset, as well as in a dataset from a cohort at Montefiore Medical Center (MMC). Protein expression was similarly evaluated in a panel of HNSCC cell lines (HN30, HN31, HN5, MDA686LN, UMSCC47). Cell viability and Annexin V assays were used to assess the efficacy and apoptotic potential of a variety of agents (ABT-263 [navitoclax], A-1210477, and bortezomib.

RESULTS

Expression of BAK, BAX, BCL2L1, and MCL1 were each significantly higher than expression of BCL2 in the TCGA and MMC datasets. Protein expression demonstrated the same pattern of expression when examined in HNSCC cell lines. Treatment with combined ABT-263 (navitoclax)/A-1210477 or with bortezomib demonstrated apoptosis responses that approached or exceeded treatment with staurospaurine control.

CONCLUSION

HNSCC cells rely on inhibition of apoptosis via BCL-xL and MCL-1 overexpression, and induction of apoptosis remains a potential therapeutic option as long as strategies overcome redundant anti-apoptotic signals.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:2643-2649, 2020.

Cu(ii) phenanthroline–phenazine complexes dysregulate mitochondrial function and stimulate apoptosis

Herein we report the central role of the mitochondria in the cytotoxicity of four developmental cytotoxic copper(ii) complexes [Cu(phen)₂]²⁺, [Cu(DPQ)(Phen)]²⁺, [Cu(DPPZ)(Phen)]²⁺and [Cu(DPPN)(Phen)]²⁺superior to cisplatin and independent of resistance in a range of cells.

Adaptive Responses to Monotherapy in Head and Neck Cancer: Interventions for Rationale-Based Therapeutic Combinations

Most Phase II and III clinical trials in head and neck cancer (HNC) combine two or more treatment modalities, which are based, in part, on knowledge of the molecular mechanisms of innate and acquired resistance to monotherapy. In this review, we describe the range of tumor-cell autonomously derived (intrinsic) and tumor-microenvironment-derived (extrinsic) acquired-resistance mechanisms to various FDA-approved monotherapies for HNC. Specifically, we describe how tumor cells and the tumor microenvironment (TME) respond to radiation, chemotherapy, targeted therapy (cetuximab), and immunotherapies [programmed cell death 1 (PD-1) inhibitors] and adapt to the selective pressure of these monotherapies. Due to the diversity of adaptive responses to monotherapy, monitoring the response to treatment in patients is critical to understand the path that leads to resistance and to guide the optimal therapeutic drug combinations in the clinical setting. We envisage that applying such a rationale-based therapeutic strategy will improve treatment efficacy in HNC patients.

Optimal targeting of BCL-family proteins in head and neck squamous cell carcinoma requires inhibition of both BCL-xL and MCL-1

Mechanisms of treatment resistance in head and neck squamous cell carcinoma (HNSCC) are not well characterized. In this study, HNSCC tumors from a cohort of prospectively enrolled subjects on an ongoing tissue banking study were divided into those that persisted or recurred locoregionally (n=23) and those that responded without recurrence (n=35). Gene expression was evaluated using llumina HumanHT-12-v3 Expression BeadChip microarrays. Sparse Partial Least Squares - Discriminant Analysis (sPLS-DA) identified 135 genes discriminating treatment-resistant from treatment-sensitive tumors. BCL-xL was identified among 23% of canonical pathways derived from this set of genes using Ingenuity Pathway analysis. The BCL-xL protein was expressed in 8 HNSCC cell lines examined. Cells were treated with the BCL-xL inhibitor, ABT-263 (navitoclax): the average half maximal inhibitory concentration (IC50) was 8.9μM (range 6.6μM - 13.9μM). Combining ABT-263 did not significantly increase responses to 2 Gy radiation or cisplatin in the majority of cell lines. MCL-1, a potential mediator of resistance to ABT-263, was expressed in all cell lines and HNSCC patient tumors, in addition to BCL-xL. Treatment with the MCL-1 inhibitor, A-1210477, in HNSCC cell lines showed an average IC50 of 10.7μM (range, 8.8μM to 12.7μM). Adding A-1210477 to ABT-263 (navitoclax) treatment resulted in an average 7-fold reduction in the required lethal dose of ABT-263 (navitoclax) when measured across all 8 cell lines. Synergistic activity was confirmed in PCI15B, Detroit 562, MDA686LN, and HN30 based on Bliss Independence analysis. This study demonstrates that targeting both BCL-xL and MCL-1 is required to optimally inhibit BCL-family pro-survival molecules in HNSCC, and co-inhibition is synergistic in HNSCC cancer cells.

The association of Bcl-xL and p53 expression with survival outcomes in oropharyngeal cancer

BACKGROUND

The role of molecular biomarkers in oropharyngeal squamous cell carcinoma (OPSCC) has recently been increasingly recognized. There is conflicting evidence in the literature with regards to the prognostic value of p53 and Bcl-xL.

OBJECTIVE

The purpose of this study was to investigate the association between p53 and Bcl-xL expression profiles and survival outcomes in OPSCC.

METHODS

Patients diagnosed with OPSCC and treated with curative intent between 1998 and 2009 were included in the study. Patient demographics, disease, treatment, and oncologic outcomes were collected prospectively. A tissue microarray (TMA) from patients' biopsies or surgical specimens was retrospectively constructed. The expression levels of p53, Bcl-xL, and p16 were digitally quantified and correlated to patient survival outcomes.

RESULTS

One hundred and sixty-six patients were included (mean age 56.7 years; standard deviation (SD) ± 10.0; 78% male). High expression of Bcl-xL (p= 0.04) was significantly associated with nodal disease at presentation, and decreased overall survival (OS) (p= 0.04). Combined expression of low Bcl-xL and low p53 conferred a survival advantage in non-smokers (p= 0.04). Multivariate analysis supported smoking and p16 status as independent prognosticators for OS.

CONCLUSIONS

This study suggests that biomarker profiling using Bcl-xL and p53 levels may be of prognostic value in select patients with OPSCC.

Induction of the Endoplasmic Reticulum Stress Pathway by Highly Cytotoxic Organoruthenium Schiff-Base Complexes

Current anticancer drug discovery efforts focus on the identification of first-in-class compounds with a mode-of-action distinct from conventional DNA-targeting agents for chemotherapy. An emerging trend is the identification of endoplasmic reticulum (ER) targeting compounds that induce ER stress in cancer cells, leading to cell death. However, a limited pool of such compounds has been identified to date, and there are limited studies done on such compounds to allow for the rational design of ER stress-inducing agents. In our present study, we present a series of highly cytotoxic, ER stress-inducing Ru(II)-arene Schiff-Base (RAS) complexes, bearing iminoquinoline chelate ligands. We demonstrate that by structural modification to the iminoquinoline ligand, we could tune its π-acidity and influence reactive oxygen species (ROS) induction, switching between a ROS-mediated ER stress pathway activation and one that is not mediated by ROS induction. Our current study adds to the available ER stress inducers and shows how structural tuning could be used as a means to modulate the mode-of-action of such compounds.

ABT-199-mediated inhibition of Bcl-2 as a potential therapeutic strategy for nasopharyngeal carcinoma

BACKGROUND

Aberrant overexpression of Bcl-2 protein has been detected in 80% of nasopharyngeal carcinoma (NPC), and Bcl-2 family proteins are implicated in both NPC oncogenesis and chemotherapy resistance. Previous studies have shown that while treatment of NPC cells with Bcl-2 family inhibitors alone is rarely effective, concomitant treatment with a cytotoxic reagent such as cisplatin can increase efficacy through a synergistic effect. The aim of the current work was to determine how we might increase the efficacy of Bcl-2 family inhibitors in the absence of cytotoxic reagents, which are associated with negative side effect profiles.

METHODS

We assessed cell proliferation in Bcl-2 high-expressing NPC cells by CCK-8 assay after treatment with the Bcl-2 inhibitor ABT-199 and/or the Mcl-1 inhibitor S63845. Apoptotic induction by ABT-199 was evaluated by Annexin V-FITC and PI double staining. We also evaluated Bcl-2 family protein expression (Bim, Mcl-1, Bcl-xL, Noxa) after treatment with ABT-199 by western blotting. Finally, xenografted Balb/c nude mice were used to test ABT-199 efficacy in vivo, H&E and immunohistochemistry assay were used to analyze tumor samples.

RESULTS

ABT-199 effectively induced NPC cell apoptosis in vitro and in the xenograft model. Following ABT-199 treatment in NPC cells, upregulation of Mcl-1 and Bcl-xL can lead to drug resistance, while concomitant Noxa overexpression partially neutralized the Mcl-1-caused resistance. Given that ABT-199 induces apoptosis in NPC cells through the Bcl-2/Noxa/Mcl-1 axis, treatment avenues further targeting this pathway should be promising. Indeed, the newly developed Mcl-1 inhibitor S63845 in combination with ABT-199 had a synergistic effect on NPC cell apoptosis.

CONCLUSION

Bcl-2 inhibition in NPC cells with ABT-199 triggers apoptosis through the Bcl-2/Noxa/Mcl-1 axis, and dual inhibition of the anti-apoptotic Bcl-2 family proteins Bcl-2 and Mcl-1 provided a strong synergistic effect without the need for adjunctive cytotoxic agent treatment with cisplatin.

NRAGE confers poor prognosis and promotes proliferation, invasion, and chemoresistance in gastric cancer

Neurotrophin receptor-interacting melanoma antigen-encoding protein (NRAGE) is a type II melanoma-associated antigen that plays an essential role in various processes, including cell differentiation and apoptosis. NRAGE has been shown to act as a cancer-related protein, with complex and apparently contradictory functions in a variety of cancers. In the current study, we examined the expression of NRAGE protein in 169 gastric cancer samples. NRAGE upregulation was correlated with advanced TNM stage, local invasion, and poor survival. Importantly, NRAGE could serve as an independent prognostic factor in patients with gastric cancer. We also examined the expression of NRAGE protein in GES-1 normal gastric epithelial cells and in six gastric cancer cell lines. Inhibition of NRAGE expression by transfection with small interfering RNA reduced the proliferation and invasion of MGC-803 and HGC-27 cells, as demonstrated by CCK-8 and Matrigel invasion assays. NRAGE depletion also sensitized HGC-27 and MGC-803 cells to cisplatin, as shown by CCK-8 and Annexin V/propidium iodide analyses. Western blot analysis also showed that NRAGE depletion negatively regulated Bcl-2 and p-ERK and upregulated ZO-1 and p27 expression levels. In conclusion, our results suggest that NRAGE acts as a tumor promoter in gastric cancer by facilitating cancer invasion and chemoresistance, possibly through regulation of p-ERK and Bcl-2.

53BP1 inhibits the migration and regulates the chemotherapy resistance of ovarian cancer cells

The major problems faced during the treatment of ovarian cancer are metastasis and the development of intrinsic or acquired drug resistance. The present study assessed whether tumor protein p53 binding protein 1 (53BP1) regulated migration and modulated chemotherapy resistance in SKOV3 cells and identified proteins associated with the molecular mechanisms underlying this coordinate regulation. SKOV3 cells were transfected using a 53BP1-expressing vector, which induced 53BP1 overexpression. The migration of the transfected cells was observed using a Transwell assay. The expression of matrix metalloproteinase (MMP)-2 and MMP-9 were assayed using gelatin zymography. In addition, the effects of 53BP1 on the chemosensitivity of SKOV3 cells to cisplatin were evaluated using MTT and western blot assays. Compared with the control, the average number of migrating SKOV3/pLPC-53BP1 cells was decreased from 230±58 to 45±12 (P<0.05) and the protein expression of MMP-9 was significantly inhibited. However, the chemosensitivity of SKOV3/pLPC-53BP1 to cisplatin decreased significantly: Cisplatin half maximal inhibitory concentration (IC⁵⁰) for SKOV3/pLPC-53BP1=7.58±0.51 µg/ml; cisplatin IC⁵⁰ for control=2.98±0.27 µg/ml (P<0.01). Decreased chemosensitivity to cisplatin may be associated with increased expression of phosphorylated-protein kinase B and cyclin dependent kinase 2 and with decreased expression of p21 and the B cell lymphoma (Bcl)-2 associated X/Bcl-2 ratio. The results of the present study demonstrated that 53BP1 may inhibit migration but upregulate chemoresistance to cisplatin in SKOV3 cells.

Multifaceted Mechanisms of Cisplatin Resistance in Long-Term Treated Urothelial Carcinoma Cell Lines

Therapeutic efficacy of cisplatin-based treatment of late stage urothelial carcinoma (UC) is limited by chemoresistance. To elucidate underlying mechanisms and to develop new approaches for overcoming resistance, we generated long-term cisplatin treated (LTT) UC cell lines, characterised their cisplatin response, and determined the expression of molecules involved in cisplatin transport and detoxification, DNA repair, and apoptosis. Inhibitors of metallothioneins and Survivin were applied to investigate their ability to sensitise towards cisplatin. Cell growth, proliferation, and clonogenicity were examined after cisplatin treatment by MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, EdU (5-ethynyl-2’-deoxyuridine) incorporation assay, and Giemsa staining, respectively. Cell cycle distribution and apoptosis were quantified by flow cytometry. mRNA and protein expressions were measured by real-time quantitative (qRT)-PCR, western blot, or immunofluorescence staining. LTTs recovered rapidly from cisplatin stress compared to parental cells. In LTTs, to various extents, cisplatin exporters and metallothioneins were induced, cisplatin adduct levels and DNA damage were decreased, whereas expression of DNA repair factors and specific anti-apoptotic factors was elevated. Pharmacological inhibition of Survivin, but not of metallothioneins, sensitised LTTs to cisplatin, in an additive manner. LTTs minimise cisplatin-induced DNA damage and evade apoptosis by increased expression of anti-apoptotic factors. The observed diversity among the four LTTs highlights the complexity of cisplatin resistance mechanisms even within one tumour entity, explaining heterogeneity in patient responses to chemotherapy.

Obatoclax impairs lysosomal function to block autophagy in cisplatin-sensitive and -resistant esophageal cancer cells

Obatoclax, a pan-inhibitor of anti-apoptotic Bcl-2 proteins, exhibits cytotoxic effect on cancer cells through both apoptosis-dependent and -independent pathways. Here we show that obatoclax caused cytotoxicity in both cisplatin-sensitive and -resistant esophageal cancer cells. Although obatoclax showed differential apoptogenic effects in these cells, it consistently blocked autophagic flux, which was evidenced by concomitant accumulation of LC3-II and p62. Obatoclax was trapped in lysosomes and induced lysosome clustering. Obatoclax also substantially reduced the expression of lysosomal cathepsins B, D and L. Moreover, cathepsin knockdown was sufficient to induce cytotoxicity, connecting lysosomal function to cell viability. Consistent with the known function of autophagy, obatoclax caused the accumulation of polyubiquitinated proteins and showed synergy with proteasome inhibition. Taken together, our studies unveiled impaired lysosomal function as a novel mechanism whereby obatoclax mediates its cytotoxic effect in esophageal cancer cells.

Asplatin enhances drug efficacy by altering the cellular response

Aspirin, a widely used anti-inflammatory drug, has been shown to be effective for the prevention and remission of cancers (Science, 2012, 337(21) 1471-1473). Asplatin, a Pt(iv) prodrug of cisplatin with the ligation of aspirin (c,c,t-[PtCl2(NH3)2(OH)(aspirin)]), demonstrates significantly higher cytotoxicity than cisplatin towards tumor cells and almost fully overcomes the drug resistance of cisplatin resistant cells. In this work, we have studied the molecular mechanism of asplatin by investigating the cellular response to this compound in order to understand the prominent inhibitory effect on the proliferation of cancer cells. The apoptosis analyses and the related gene expression measurements show that aspirin released from asplatin significantly modulates the cellular response to the platinum agent. Asplatin promotes the apoptosis via the BCL-2 associated mitochondrial pathway. The down-regulation of BCL-2 along with the up-regulation of BAX and BAK enhances the mitochondrial outer membrane permeability, resulting in the cytochrome c release from mitochondria into the cytosol. This event promotes the apoptosis by activation of caspase processing. Consequently, the ligation of aspirin significantly enhances the drug efficacy of the platinum complex in the low micromolar range. The alteration of the cellular response is probably responsible for the circumvention of the cisplatin resistance by asplatin. These results provide an insight into the mechanism of asplatin and provide information for designing new classic platinum drugs.

Apoptosis as anticancer mechanism: function and dysfunction of its modulators and targeted therapeutic strategies

Apoptosis is a form of programmed cell death that results in the orderly and efficient removal of damaged cells, such as those resulting from DNA damage or during development. Apoptosis can be triggered by signals from within the cell, such as genotoxic stress, or by extrinsic signals, such as the binding of ligands to cell surface death receptors. Deregulation in apoptotic cell death machinery is an hallmark of cancer. Apoptosis alteration is responsible not only for tumor development and progression but also for tumor resistance to therapies. Most anticancer drugs currently used in clinical oncology exploit the intact apoptotic signaling pathways to trigger cancer cell death. Thus, defects in the death pathways may result in drug resistance so limiting the efficacy of therapies. Therefore, a better understanding of the apoptotic cell death signaling pathways may improve the efficacy of cancer therapy and bypass resistance. This review will highlight the role of the fundamental regulators of apoptosis and how their deregulation, including activation of anti-apoptotic factors (i.e., Bcl-2, Bcl-xL, etc) or inactivation of pro-apoptotic factors (i.e., p53 pathway) ends up in cancer cell resistance to therapies. In addition, therapeutic strategies aimed at modulating apoptotic activity are briefly discussed.

Selective Targeting of Cancer Cells by Oxidative Vulnerabilities with Novel Curcumin Analogs

Recently, research has focused on targeting the oxidative and metabolic vulnerabilities in cancer cells. Natural compounds like curcumin that target such susceptibilities have failed further clinical advancements due to the poor stability and bioavailability as well as the need of high effective doses. We have synthesized and evaluated the anti-cancer activity of several monocarbonyl analogs of curcumin. Interestingly, two novel analogs (Compound A and I) in comparison to curcumin, have increased chemical stability and have greater anti-cancer activity in a variety of human cancer cells, including triple-negative, inflammatory breast cancer cells. In particular, the generation of reactive oxygen species was selective to cancer cells and occurred upstream of mitochondrial collapse and execution of apoptosis. Furthermore, Compound A in combination with another cancer-selective/pro-oxidant, piperlongumine, caused an enhanced anti-cancer effect. Most importantly, Compound A was well tolerated by mice and was effective in inhibiting the growth of human triple-negative breast cancer and leukemia xenografts in vivo when administered intraperitoneally. Thus, exploiting oxidative vulnerabilities in cancer cells could be a selective and efficacious means to eradicate malignant cells as demonstrated by the curcumin analogs presented in this report with high therapeutic potential.

ABT-737 Synergizes with Cisplatin Bypassing Aberration of Apoptotic Pathway in Non-small Cell Lung Cancer

A subset of non-small cell lung cancer (NSCLC), which does not have a druggable driver mutation, is treated with platinum-based cytotoxic chemotherapy, but it develops resistance triggered by DNA damage responses. Here, we investigated the effect of activation of STAT3 by cisplatin on anti-apoptotic proteins and the effectiveness of a co-treatment with cisplatin and a BH3 mimetic, ABT-737. We analyzed the relationship between cisplatin and STAT3 pathway and effect of ABT-737, when combined with cisplatin in NSCLC cells and K-ras mutant mouse models. The synergism of this combination was evaluated by the Chou-Talalay Combination Index method. In vivo activity was evaluated by micro-CT. In NSCLC cells, there was a time and dose-dependent phosphorylation of SRC-JAK2-STAT3 by cisplatin, followed by increased expression of anti-apoptotic molecules. When the expression of the BCL-2 protein family members was evaluated in clinical samples, BCL-xL was most frequently overexpressed. Dominant negative STAT3 suppressed their expression, suggesting that STAT3 mediates cisplatin mediated overexpression of the anti-apoptotic molecules. ABT-737 displaced BCL-xL from mitochondria and induced oligomerization of BAK. ABT-737 itself showed cytotoxic effects and a combination of ABT-737 with cisplatin showed strong synergistic cytotoxicity. In a murine lung cancer model, co-treatment with ABT-737 and cisplatin induced significant tumor regression. These findings reveal a synergistic cytotoxic and anti-tumor activity of ABT-737 and cisplatin co-treatment in preclinical models, and suggest that clinical trials using this strategy may be beneficial in advanced NSCLC.

CMTM1_v17 is associated with chemotherapy resistance and poor prognosis in non-small cell lung cancer

Background

Considering neoadjuvant chemotherapy (NAC) prior to surgery could shrink and reduce the primary tumor and distant micro-metastases to reduce the high relapses rates, NAC has been an accepted therapeutic management for patients with non-small cell lung cancer (NSCLC). CMTM1_v17 is highly expressed in human testis tissues and solid tumor tissues but relatively low expression was obtained in the corresponding normal tissues. This study aims to investigate the significance of CMTM1_v17 in NSCLC and its association with platinum-based NAC efficacy.

Methods

31 pairs of tumor tissues before and after NAC and 78 resected tumor tissues after NAC were utilized for immunohistochemistry (IHC) staining of CMTM1_v17 protein. The correlation between CMTM1_v17 expression and chemotherapy efficacy was analyzed. The prognostic value of CMTM1_v17 index for disease-free survival (DFS) and overall survival (OS) was analyzed using Kaplan-Meier survival and multivariable Cox regression.

Results

CMTM1_v17 expression was related to treatment effect and outcome in tumor tissues after NAC not before NAC from 31 cases of NSCLC. We identified that high CMTM1_v17 expression was associated with low objective remission rate (ORR) (P = 0.008) and poor prognosis (the median OS: 35.1 months vs 65.6 months, P = 0.0045; the median DFS: 17.27 months vs 35.54 months, P = 0.0207) in the 31 patients. Next, we detected CMTM1_v17 expression to confirm correlation between this protein status and clinical characteristics in 78 NSCLC patients with NAC treatment. The upregulation of CMTM1_v17 had a higher SD rate (P = 0.007) and worse outcome (the median OS: 41.0 months vs 80.6 months, P = 0.0028; the median DFS: 33.4 vs 64.8 months, P = 0.0032). COX multivariate analysis indicated that CMTM1_v17 is an independent prognostic risk factor on patients who have received NAC (OS: HR = 3.642, P = 0.002; DFS:HR = 3.094, P = 0.002).

Conclusions

CMTM1_v17 expression is significantly associated with chemoresistance and poor prognosis of the early stage NSCLC patients who have received NAC.

[50th anniversary of cisplatin]

We have just celebrated the 50th anniversary of cisplatin cytotoxic potential discovery. It is time to take stock… and it seems mainly positive. This drug, that revolutionized the treatment of many cancer types, continues to be the most widely prescribed chemotherapy. Despite significant toxicities, resistance mechanisms associated with treatment failures, and unresolved questions about its mechanism of action, the use of this cytotoxic agent remains unwavering. The interest concerning this "old" invincible drug has not yet abated. Indeed many research axes are in the news. New platinum salts agents are tested, new cisplatin formulations are developed to target tumor cells more efficiently, and new combinations are established to increase the cytotoxic potency of cisplatin or overcome the resistance mechanisms.

BH3 mimetic Obatoclax (GX15-070) mediates mitochondrial stress predominantly via MCL-1 inhibition and induces autophagy-dependent necroptosis in human oral cancer cells

We have previously reported overexpression of antiapoptotic MCL-1 protein in human oral cancers and its association with therapy resistance and poor prognosis, implying it to be a potential therapeutic target. Hence, we investigated the efficacy and mechanism of action of Obatoclax, a BH3 mimetic pan BCL-2 inhibitor in human oral cancer cell lines. All cell lines exhibited high sensitivity to Obatoclax with complete clonogenic inhibition at 200-400 nM concentration which correlated with their MCL-1 expression. Mechanistic insights revealed that Obatoclax induced a caspase-independent cell death primarily by induction of a defective autophagy. Suppression of autophagy by ATG5 downregulation significantly blocked Obatoclax-induced cell death. Further, Obatoclax induced interaction of p62 with key components of the necrosome RIP1K and RIP3K. Necrostatin-1 mediated inhibition of RIP1K significantly protected the cells from Obatoclax induced cell death. Moreover, Obatoclax caused extensive mitochondrial stress leading to their dysfunction. Interestingly, MCL-1 downregulation alone caused mitochondrial stress, highlighting its importance for mitochondrial homeostasis. We also demonstrated in vivo efficacy of Obatoclax against oral cancer xenografts and its synergism with ionizing radiation in vitro. Our studies thus suggest that Obatoclax induces autophagy-dependent necroptosis in oral cancer cells and holds a great promise in the improved management of oral cancer patients.

DKK1 is a potential novel mediator of cisplatin-refractoriness in non-small cell lung cancer cell lines

Background

Platinum compounds are the mainstay of chemotherapy for lung cancer. Unfortunately treatment failure remains a critical issue since about 60 % of all non-small cell lung cancer (NSCLC) patients display intrinsic platinum resistance.

Methods

We analyzed global gene expression profiles of NSCLC clones surviving a pulse treatment with cisplatin and mapped deregulated signaling networks in silico by Ingenuity Pathway Analysis (IPA). Further validation was done using siRNA.

Results

The pooled cisplatin-surviving NSCLC clones from each of the biological replicates demonstrated heterogeneous gene expression patterns both in terms of the number and the identity of the altered genes. Genes involved in Wnt signaling pathway (Dickkopf-1, DKK1), DNA repair machinery (XRCC2) and cell-cell/cell-matrix interaction (FMN1, LGALS9) were among the top deregulated genes by microarray in these replicates and were validated by q-RT-PCR. We focused on DKK1 which previously was reported to be overexpressed in NSCLC patients. IPA network analysis revealed coordinate up-regulation of several DKK1 transcriptional regulators (TCF4, EZH2, DNAJB6 and HDAC2) in cisplatin-surviving clones from that biological replicate. Knockdown of DKK1 by siRNA sensitized for cisplatin in two different NSCLC cell lines and in ovarian A2780 cells, but not in the A2780 cis subline made resistant to cisplatin by chronic exposure, suggesting a role of DKK1 in intrinsic but not acquired platinum refractoriness.

Conclusions

We identified DKK1 as a possible marker of a cisplatin-refractory phenotype and as a potential novel therapeutic target to improve platinum response of NSCLC cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1635-9) contains supplementary material, which is available to authorized users.

Downregulation of Vascular Endothelial Growth Factor Enhances Chemosensitivity by Induction of Apoptosis in Hepatocellular Carcinoma Cells

OBJECTIVE

Hepatocellular carcinoma (HCC), one of the most common cancers worldwide, is resistant to anticancer drugs. Angiogenesis is a major cause of tumor resistance to chemotherapy, and vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis. The purpose of this study is to investigate the impact of small-interfering RNA targeting VEGF gene (VEGF-siRNA) on chemosensitivity of HCC cells in vitro.

MATERIALS AND METHODS

In this experimental study, transfection was performed on Hep3B cells. After transfection with siRNAs, VEGF mRNA and protein levels were examined. Cell proliferation, apoptosis and anti-apoptotic gene expression were also analyzed after treatment with VEGF-siRNA in combination with doxorubicin in Hep3B cells.

RESULTS

Transfection of VEGF-siRNA into Hep3B cells significantly reduced the expression of VEGF at both mRNA and protein levels. Combination therapy with VEGF-siRNA and doxorubicin more effectively suppressed cell proliferation and induced apoptosis than the respective monotherapies. This could be explained by the significant downregulation of B-cell lymphoma 2 (BCL-2) and SURVIVIN.

CONCLUSION

VEGF-siRNA enhanced the chemosensitivity of doxorubicin in Hep3B cells at least in part by suppressing the expression of anti-apoptotic genes. Therefore, the downregulation of VEGF by siRNA combined with doxorubicin treatment has been shown to yield promising results for eradicating HCC cells.

ABT737 enhances cholangiocarcinoma sensitivity to cisplatin through regulation of mitochondrial dynamics

Cholangiocarcinoma responses weakly to cisplatin. Mitochondrial dynamics participate in the response to various stresses, and mainly involve mitophagy and mitochondrial fusion and fission. Bcl-2 family proteins play critical roles in orchestrating mitochondrial dynamics, and are involved in the resistance to cisplatin. Here we reported that ABT737, combined with cisplatin, can promote cholangiocarcinoma cells to undergo apoptosis. We found that the combined treatment decreased the Mcl-1 pro-survival form and increased Bak. Cells undergoing cisplatin treatment showed hyperfused mitochondria, whereas fragmentation was dominant in the mitochondria of cells exposed to the combined treatment, with higher Fis1 levels, decreased Mfn2 and OPA1 levels, increased ratio of Drp1 60kD to 80kD form, and more Drp1 located on mitochondria. More p62 aggregates were observed in cells with fragmented mitochondria, and they gradually translocated to mitochondria. Mitophagy was induced by the combined treatment. Knockdown p62 decreased the Drp1 ratio, increased Tom20, and increased cell viability. Our data indicated that mitochondrial dynamics play an important role in the response of cholangiocarcinoma to cisplatin. ABT737 might enhance cholangiocarcinoma sensitivity to cisplatin through regulation of mitochondrial dynamics and the balance within Bcl-2 family proteins. Furthermore, p62 seems to be critical in the regulation of mitochondrial dynamics.

The challenge of blocking a wider family members of EGFR against head and neck squamous cell carcinomas

Head and neck squamous cell carcinoma (HNSCC) represent 95% of head and neck cancer with an incidence of over half a million people globally. The prognosis for patients with recurrent or metastatic HNSCC is generally poor with low 5-year survival rates despite treatment advances over the past few decades. Consequently, it is essential to search for new biomarkers and effective therapy options to optimize HNSCC treatment. Epidermal growth factor receptor (EGFR) is overexpressed in approximately 90% of tumours. EGFR has become one of most common targets for new therapies being investigated in HNSCC. In this way, multiple therapies targeting EGFR in HNSCC have been tested but response rates are still low especially in the recurrent or metastatic setting. This has been attributed to mechanisms of resistance to EGFR-targeted therapies. Afatinib, an oral small molecule ErbB Family Blocker that irreversibly binds to ErbB1 (EGFR), ErbB2 (HER2) and ErbB4 (HER4), is being investigated in HNSCC treatment with encouraging phase II results and several ongoing phase III trials. Results of these trials will help to understand the place of afatinib in the HNSCC treatment armamentarium.

Designing biomarker studies for head and neck cancer

Although there is ample literature reporting on the identification of molecular biomarkers for head and neck squamous cell carcinoma, none is currently recommended for routine clinical use. A major reason for this lack of progress is the difficulty in designing studies in head and neck cancer to clearly establish the clinical utility of biomarkers. Consequently, biomarker studies frequently stall at the initial discovery phase. In this article, we focus on biomarkers for use in clinical management, including selection of therapy. Using several contemporary examples, we identify some of the common deficiencies in study design that hinder success in biomarker development for this disease area, and we suggest some potential solutions. The purpose of this article is to provide guidance that can assist investigators to more efficiently move promising biomarkers in head and neck cancer from discovery to clinical practice

MiR-363 sensitizes cisplatin-induced apoptosis targeting in Mcl-1 in breast cancer

Myeloid cell leukemia-1 (Mcl-1) is an anti-apoptotic Bcl-2 family member that is often overexpressed in breast tumors, and has been reported to have an important role in regulating drug resistance in various types of cancer including breast cancer. However, the mechanisms underlying the aberrant expression of Mcl-1 are still unclear. In this study, we used bioinformatics, cellular, and molecular methods to predict and prove that miR-363 directly targeted Mcl-1 3'-UTR (3'-untranslated regions) and caused downregulation of Mcl-1 in breast cancer. Resistance to chemotherapy is a major barrier for the effective treatment for advanced breast cancer, but our study indicated that miR-363 reversed the resistance of the breast cancer cell line MDA-MB-231 to the chemotherapeutic agent cisplatin (CDDP). In addition, transfection of breast cancer cells with Mcl-1 expression plasmid abolished the sensitization effect of miR-363 to cisplatin-inducing cytotoxicity. In summary, our study showed that miR-363 was a negative regulator of Mcl-1 expression, and the combination of miR-363 and cisplatin may be a novel approach in the treatment for breast cancer.