A randomized phase II study of ganetespib, a heat shock protein 90 inhibitor, in combination with docetaxel in second-line therapy of advanced non-small cell lung cancer (GALAXY-1)

An update on the status of HSP90 inhibitors in cancer clinical trials

The evolutionary conserved molecular chaperone heat shock protein 90 (HSP90) plays an indispensable role in tumorigenesis by stabilizing client oncoproteins. Although the functionality of HSP90 is tightly regulated, cancer cells exhibit a unique dependence on this chaperone, leading to its overexpression, which has been associated with poor prognosis in certain malignancies. While various strategies targeting heat shock proteins (HSPs) involved in carcinogenesis have been explored, only inhibition of HSP90 has consistently and effectively resulted in proteasomal degradation of its client proteins. To date, a total of 22 HSP90 inhibitors (HSP90i) have been tested in 186 cancer clinical trials, as reported by clinicaltrials.gov. Among these trials, 60 % have been completed, 10 % are currently active, and 30 % have been suspended, terminated, or withdrawn. HSP90 inhibitors (HSP90i) have been used as single agents or in combination with other drugs for the treatment of various cancer types in clinical trials. Notably, improved clinical outcomes have been observed when HSP90i are used in combination therapies, as they exhibit a synergistic antitumor effect. However, as single agents, HSP90i have shown limited clinical activity due to drug-related toxicity or therapy resistance. Recently, active trials conducted in Japan evaluating TAS-116 (pimitespib) have demonstrated promising results with low toxicity as monotherapy and in combination with the immune checkpoint inhibitor nivolumab. Exploratory biomarker analyses performed in various trials have demonstrated target engagement that suggests the potential for identifying patient populations that may respond favorably to the therapy. In this review, we discuss the advances made in the past 5 years regarding HSP90i and their implications in anticancer therapeutics. Our focus lies in evaluating drug efficacy, prognosis forecast, pharmacodynamic biomarkers, and clinical outcomes reported in published trials. Through this comprehensive review, we aim to shed light on the progress and potential of HSP90i as promising therapeutic agents in cancer treatment.

Combination therapy involving HSP90 inhibitors for combating cancer: an overview of clinical and preclinical progress

The molecular chaperone heat shock protein 90 (HSP90) regulates multiple crucial signalling pathways in cancer by driving the maturation of key signalling components, thereby playing a crucial role in tumorigenesis and drug resistance in cancer. Inhibition of HSP90 results in metastable conformational collapse of its client proteins and their proteasomal degradation. Considerable efforts have been devoted to the development of small-molecule inhibitors targeting HSP90, and more than 20 inhibitors have been evaluated in clinical trials for cancer therapy. However, owing to disadvantages such as organ toxicity and drug resistance, only one HSP90 inhibitor has been approved for use in clinical settings. In recent years, HSP90 inhibitors used in combination with other anti-cancer therapies have shown remarkable potential in the treatment of cancer. HSP90 inhibitors work synergistically with various anti-cancer therapies, including chemotherapy, targeted therapy, radiation therapy and immunotherapy. HSP90 inhibitors can improve the pharmacological effects of the above-mentioned therapies and reduce treatment resistance. This review provides an overview of the use of combination therapy with HSP90 inhibitors and other anti-cancer therapies in clinical and preclinical studies reported in the past decade and summarises design strategies and prospects for these combination therapies. Altogether, this review provides a theoretical basis for further research and application of these combination therapies in the treatment of cancer.

Hypoxia-Inducible Factor-Dependent and Independent Mechanisms Underlying Chemoresistance of Hypoxic Cancer Cells

In hypoxic regions of malignant solid tumors, cancer cells acquire resistance to conventional therapies, such as chemotherapy and radiotherapy, causing poor prognosis in patients with cancer. It is widely recognized that some of the key genes behind this are hypoxia-inducible transcription factors, e.g., hypoxia-inducible factor 1 (HIF-1). Since HIF-1 activity is suppressed by two representative 2-oxoglutarate-dependent dioxygenases (2-OGDDs), PHDs (prolyl-4-hydroxylases), and FIH-1 (factor inhibiting hypoxia-inducible factor 1), the inactivation of 2-OGDD has been associated with cancer therapy resistance by the activation of HIF-1. Recent studies have also revealed the importance of hypoxia-responsive mechanisms independent of HIF-1 and its isoforms (collectively, HIFs). In this article, we collate the accumulated knowledge of HIF-1-dependent and independent mechanisms responsible for resistance of hypoxic cancer cells to anticancer drugs and briefly discuss the interplay between hypoxia responses, like EMT and UPR, and chemoresistance. In addition, we introduce a novel HIF-independent mechanism, which is epigenetically mediated by an acetylated histone reader protein, ATAD2, which we recently clarified.

Ganetespib with Methotrexate Acts Synergistically to Impede NF-κB/p65 Signaling in Human Lung Cancer A549 Cells

Among the various types of cancer, lung cancer accounts for the highest number of fatalities across the globe. A combination of different cancer chemotherapeutics is regarded as an effective strategy for clinical management of different cancers. Ganetespib (GAN) is a well-established hsp90 inhibitor with enhanced pharmacological properties in comparison with its first-generation counterparts. Previous preclinical studies have shown that GAN exerts significant effects against cancer cells; however, its therapeutic effects against non-small cell lung cancer (NSCLC) A549 cells, achieved by modulating the expression of the NF-κB/p65 signaling pathway, remains unexplored. In this study, the combinatorial effect of GAN and methotrexate (MTX) against lung carcinomas was investigated through both in silico and in vitro studies. A combinatorial treatment regimen of GAN/MTX exerted more significant cytotoxic effects (p < 0.001) against A549 cells than individual treatments. The GAN/MTX combination also instigated nuclear fragmentation followed by augmentation in intracellular ROS levels (p < 0.001). The elevated ROS in A549 cells upon exposure to GAN/MTX combinatorial regimen was concomitantly accompanied with a remarkable reduction in mitochondrial viability. In addition, it was observed that the GAN/MTX combination succeeded in elevating caspase-3 activity and downregulating the expression levels of anti-apoptotic mediators Bcl2 and survivin in NSCLC A549 cells. Most importantly, the GAN/MTX combinatorial regimen impeded the activation of the NF-kB/p65 signaling pathway via repression of the expression of E-cadherin and N-cadherin, which was confirmed by molecular docking studies. Collectively, these findings demonstrated the synergistic effect of the GAN/MTX combinatorial regimen in suppressing the growth of A549 cells by modulating the NF-κB/p65 signaling pathway.

Safety and efficacy of HSP90 inhibitor ganetespib for neoadjuvant treatment of stage II/III breast cancer

HSP90 inhibitors destabilize oncoproteins associated with cell cycle, angiogenesis, RAS-MAPK activity, histone modification, kinases and growth factors. We evaluated the HSP90-inhibitor ganetespib in combination with standard chemotherapy in patients with high-risk early-stage breast cancer. I-SPY2 is a multicenter, phase II adaptively randomized neoadjuvant (NAC) clinical trial enrolling patients with stage II-III breast cancer with tumors 2.5 cm or larger on the basis of hormone receptors (HR), HER2 and Mammaprint status. Multiple novel investigational agents plus standard chemotherapy are evaluated in parallel for the primary endpoint of pathologic complete response (pCR). Patients with HER2-negative breast cancer were eligible for randomization to ganetespib from October 2014 to October 2015. Of 233 women included in the final analysis, 140 were randomized to the standard NAC control; 93 were randomized to receive 150 mg/m2 ganetespib every 3 weeks with weekly paclitaxel over 12 weeks, followed by AC. Arms were balanced for hormone receptor status (51-52% HR-positive). Ganetespib did not graduate in any of the biomarker signatures studied before reaching maximum enrollment. Final estimated pCR rates were 26% vs. 18% HER2-negative, 38% vs. 22% HR-negative/HER2-negative, and 15% vs. 14% HR-positive/HER2-negative for ganetespib vs control, respectively. The predicted probability of success in phase 3 testing was 47% HER2-negative, 72% HR-negative/HER2-negative, and 19% HR-positive/HER2-negative. Ganetespib added to standard therapy is unlikely to yield substantially higher pCR rates in HER2-negative breast cancer compared to standard NAC, and neither HSP90 pathway nor replicative stress expression markers predicted response. HSP90 inhibitors remain of limited clinical interest in breast cancer, potentially in other clinical settings such as HER2-positive disease or in combination with anti-PD1 neoadjuvant chemotherapy in triple negative breast cancer.Trial registration: www.clinicaltrials.gov/ct2/show/NCT01042379.

Chaperone-assisted E3 ligase CHIP: A double agent in cancer

The carboxy-terminus of Hsp70-interacting protein (CHIP) is a ubiquitin ligase and co-chaperone belonging to Ubox family that plays a crucial role in the maintenance of cellular homeostasis by switching the equilibrium of the folding-refolding mechanism towards the proteasomal or lysosomal degradation pathway. It links molecular chaperones viz. HSC70, HSP70 and HSP90 with ubiquitin proteasome system (UPS), acting as a quality control system. CHIP contains charged domain in between N-terminal tetratricopeptide repeat (TPR) and C-terminal Ubox domain. TPR domain interacts with the aberrant client proteins via chaperones while Ubox domain facilitates the ubiquitin transfer to the client proteins for ubiquitination. Thus, CHIP is a classic molecule that executes ubiquitination for degradation of client proteins. Further, CHIP has been found to be indulged in cellular differentiation, proliferation, metastasis and tumorigenesis. Additionally, CHIP can play its dual role as a tumor suppressor as well as an oncogene in numerous malignancies, thus acting as a double agent. Here, in this review, we have reported almost all substrates of CHIP established till date and classified them according to the hallmarks of cancer. In addition, we discussed about its architectural alignment, tissue specific expression, sub-cellular localization, folding-refolding mechanisms of client proteins, E4 ligase activity, normal physiological roles, as well as involvement in various diseases and tumor biology. Further, we aim to discuss its importance in HSP90 inhibitors mediated cancer therapy. Thus, this report concludes that CHIP may be a promising and worthy drug target towards pharmaceutical industry for drug development.

Evaluation of the Heat Shock Protein 90 Inhibitor Ganetespib as a Sensitizer to Hyperthermia-Based Cancer Treatments

Simple Summary

Hyperthermia boosts the effects of radio- and chemotherapy regimens, but its clinical potential is hindered by the ability of (cancer) cells to activate a protective mechanism known as the heat stress response. Strategies that inhibit its activation or functions have the potential, therefore, to improve the overall efficacy of hyperthermia-based treatments. In this study, we evaluated the efficacy of the HSP90 inhibitor ganetespib in promoting the effects of radiotherapy or cisplatin combined with hyperthermia in vitro and in a cervix cancer mouse model.

Abstract

Hyperthermia is being used as a radio- and chemotherapy sensitizer for a growing range of tumor subtypes in the clinic. Its potential is limited, however, by the ability of cancer cells to activate a protective mechanism known as the heat stress response (HSR). The HSR is marked by the rapid overexpression of molecular chaperones, and recent advances in drug development make their inhibition an attractive option to improve the efficacy of hyperthermia-based therapies. Our previous in vitro work showed that a single, short co-treatment with a HSR (HSP90) inhibitor ganetespib prolongs and potentiates the effects of hyperthermia on DNA repair, enhances hyperthermic sensitization to radio- and chemotherapeutic agents, and reduces thermotolerance. In the current study, we first validated these results using an extended panel of cell lines and more robust methodology. Next, we examined the effects of hyperthermia and ganetespib on global proteome changes. Finally, we evaluated the potential of ganetespib to boost the efficacy of thermo-chemotherapy and thermo-radiotherapy in a xenograft murine model of cervix cancer. Our results revealed new insights into the effects of HSR inhibition on cellular responses to heat and show that ganetespib could be employed to increase the efficacy of hyperthermia when combined with radiation.

Targeting Mutant p53 for Cancer Treatment: Moving Closer to Clinical Use?

Simple Summary

Cancer is largely caused by genetic alterations such as mutations in a group of genes known as cancer driver genes. Many of the key advances in cancer treatment in recent years have involved blocking these driver genes using a new generation of anti-cancer drugs. Although p53 is the most frequently mutated gene in human cancers, historically, it has proved difficult to develop drugs against it. However, recently, several new drugs have become available for neutralizing the cancer-promoting effects of mutant p53. The aim of this article is to discuss the most promising of these drugs, especially those that are being investigated in clinical trials.

Abstract

Mutant p53 is one of the most attractive targets for new anti-cancer drugs. Although traditionally regarded as difficult to drug, several new strategies have recently become available for targeting the mutant protein. One of the most promising of these involves the use of low molecular weight compounds that promote refolding and reactivation of mutant p53 to its wild-type form. Several such reactivating drugs are currently undergoing evaluation in clinical trials, including eprenetapopt (APR-246), COTI-2, arsenic trioxide and PC14586. Of these, the most clinically advanced for targeting mutant p53 is eprenetapopt which has completed phase I, II and III clinical trials, the latter in patients with mutant TP53 myelodysplastic syndrome. Although no data on clinical efficacy are currently available for eprenetapopt, preliminary results suggest that the drug is relatively well tolerated. Other strategies for targeting mutant p53 that have progressed to clinical trials involve the use of drugs promoting degradation of the mutant protein and exploiting the mutant protein for the development of anti-cancer vaccines. With all of these ongoing trials, we should soon know if targeting mutant p53 can be used for cancer treatment. If any of these trials show clinical efficacy, it may be a transformative development for the treatment of patients with cancer since mutant p53 is so prevalent in this disease.

Targeting Heat-Shock Protein 90 in Cancer: An Update on Combination Therapy

Heat-shock protein 90 (HSP90) is an important molecule chaperone associated with tumorigenesis and malignancy. HSP90 is involved in the folding and maturation of a wide range of oncogenic clients, including diverse kinases, transcription factors and oncogenic fusion proteins. Therefore, it could be argued that HSP90 facilitates the malignant behaviors of cancer cells, such as uncontrolled proliferation, chemo/radiotherapy resistance and immune evasion. The extensive associations between HSP90 and tumorigenesis indicate substantial therapeutic potential, and many HSP90 inhibitors have been developed. However, due to HSP90 inhibitor toxicity and limited efficiency, none have been approved for clinical use as single agents. Recent results suggest that combining HSP90 inhibitors with other anticancer therapies might be a more advisable strategy. This review illustrates the role of HSP90 in cancer biology and discusses the therapeutic value of Hsp90 inhibitors as complements to current anticancer therapies.

Statins inhibit proliferation and induce apoptosis in triple-negative breast cancer cells

TP53 (p53) is mutated in 80–90% of cases of triple-negative breast cancer (TNBC). Statins, which are widely used to treat elevated cholesterol, have recently been shown to degrade mutant p53 protein and exhibit anti-cancer activity. The aim of this work was to evaluate the potential of statins in the treatment of TNBC. The anti-proliferative effects of 2 widely used statins were investigated on a panel of 15 cell lines representing the different molecular subtypes of breast cancer. Significantly lower IC50 values were found in triple-negative (TN) than in non-TN cell lines (atorvastatin, p < 0.01; simvastatin p < 0.05) indicating greater sensitivity. Furthermore, cell lines containing mutant p53 were more responsive to both statins than cell lines expressing wild-type p53, suggesting that the mutational status of p53 is a potential predictive biomarker for statin response. In addition to inhibiting proliferation, simvastatin was also found to promote cell cycle arrest and induce apoptosis. Using an apoptosis array capable of detecting 43 apoptosis-associated proteins, a novel protein shown to be upregulated by simvastatin was the IGF-signalling modulator, IGBP4, a finding we confirmed by Western blotting. Finally, we found synergistic growth inhibition between simvastatin and the IGF-1R inhibitor, OSI-906 as well as between simvastatin and doxorubicin or docetaxel. Our work suggests repurposing of statins for clinical trials in patients with TNBC. Based on our findings, we suggest that these trials investigate statins in combination with either doxorubicin or docetaxel and include p53 mutational status as a potential predictive biomarker.

The treatment of advanced non-small cell lung cancer harboring KRAS mutation: a new class of drugs for an old target-a narrative review

Background and Objective

The genetic nature of cancer provides the rationale to support the need for molecular diagnosis and patient selection for individualised antineoplastic treatments that are the best in both tolerability and efficacy for each cancer patient, including non-small cell lung cancer (NSCLC) patients. Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations represent the prevalent oncogenic driver in NSCLC, being detected in roughly one-third of cases and KRAS G12C is the most frequent mutation found in approximately 13% of patients.

Methods

This paper gives an overview of the numerous scientific efforts in recent decades aimed at KRAS inhibition.

Key Content and Findings

Sotorasib is the first approved KRAS G12C inhibitor that has been shown to provide a durable clinical benefit in patients with pre-treated NSCLC with KRAS G12C mutation. Together with the development of new targeted drugs, the development of strategies to control resistance mechanisms is one of the major drivers of research that is exploring the use of KRAS inhibitors not only alone, but also in combination with other targeted therapies, chemotherapy and immunotherapy.

Conclusions

This review will describe the major therapeutic developments in KRAS mutation-dependent NSCLC and will analyse future perspectives to maximise benefits for this group of patients.

Ganetespib selectively sensitizes cancer cells for proximal and distal spread-out Bragg peak proton irradiation

Objective

Hypersensitivity towards proton versus photon irradiation was demonstrated in homologous recombination repair (HRR)-deficient cell lines. Hence, combined treatment concepts targeting HRR provide a rational for potential pharmaceutical exploitation. The HSP90 inhibitor ganetespib (STA-9090) downregulates a multitude of HRR-associated proteins and sensitizes for certain chemotherapeutics. Thus, the radiosensitizing effect of HSP90-inhibiting ganetespib was investigated for reference photon irradiation and proton irradiation at a proximal and distal position in a spread-out Bragg peak (SOBP).

Methods

A549 and FaDu cells were treated with low-dose (2 nM resp. 1 nM) ganetespib and irradiated with 200 kV photons. Proton irradiation was performed at a proximal and a distal position within a SOBP, with corresponding dose-averaged linear-energy transfer (LET_D) values of 2.1 and 4.5 keV/µm, respectively. Cellular survival data was fitted to the linear-quadratic model to calculate relative biological effectiveness (RBE) and the dose-modifying factor (DMF). Additionally, A549 cells were treated with increasing doses of ganetespib and investigated by flow cytometry, immunoblotting, and immunofluorescence microscopy to investigate cell cycle distribution, Rad51 protein levels, and γH2AX foci, respectively.

Results

Low-dosed ganetespib significantly sensitized both cancer cell lines exclusively for proton irradiation at both investigated LET_D, resulting in increased RBE values of 10–40%. In comparison to photon irradiation, the fraction of cells in S/G2/M phase was elevated in response to proton irradiation with 10 nM ganetespib consistently reducing this population. No changes in cell cycle distribution were detected in unirradiated cells by ganetespib alone. Protein levels of Rad51 are downregulated in irradiated A549 cells by 10 nM and also 2 nM ganetespib within 24 h. Immunofluorescence staining demonstrated similar induction and removal of γH2AX foci, irrespective of irradiation type or ganetespib administration.

Conclusion

Our findings illustrate a proton-specific sensitizing effect of low-dosed ganetespib in both employed cell lines and at both investigated SOBP positions. We provide additional experimental data on cellular response and a rational for future combinatorial approaches with proton radiotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-022-02036-z.

Overcoming KRAS-Mutant Lung Cancer

More than 50 years after the discovery of RAS family proteins, which harbor the most common activating mutations in cancer, the U.S. Food and Drug Administration approved the first direct allele-specific inhibitor of mutant KRAS in lung cancer. We highlight the history of discovering RAS and decades of studies targeting KRAS-driven lung cancer. A landmark article by Shokat and colleagues in 2013 elucidated allosteric inhibition of this undruggable target and paved the way for the first-in-class direct KRAS^G12C inhibitor. Although these drugs have impressive 36%-45% objective response rates with a median duration of response of 10 months, many tumors do not respond, and diverse mechanisms of resistance have already been observed; this includes new KRAS alterations, activation of alternate RTK pathway proteins, bypass pathways, and transcriptional remodeling. These resistance mechanisms can be profiled using tissue-based and plasma-based testing and help to inform clinical trial options for patients. We conclude with a discussion of research informing ongoing clinical trials to rationally test promising treatments to thwart or overcome resistance to KRAS^G12C inhibitors and target other KRAS-altered lung cancers.

Cellular Senescence in Idiopathic Pulmonary Fibrosis

Cellular senescence (CS) is increasingly implicated in the etiology of age-related diseases. While CS can facilitate physiological processes such as tissue repair and wound healing, senescent cells also contribute to pathophysiological processes involving macromolecular damage and metabolic dysregulation that characterize multiple morbid and prevalent diseases, including Alzheimer's disease, osteoarthritis, atherosclerotic vascular disease, diabetes mellitus, and idiopathic pulmonary fibrosis (IPF). Preclinical studies targeting senescent cells and the senescence-associated secretory phenotype (SASP) with "senotherapeutics" have demonstrated improvement in age-related morbidity associated with these disease states. Despite promising results from these preclinical trials, few human clinical trials have been conducted. A first-in-human, open-label, pilot study of the senolytic combination of dasatinib and quercetin (DQ) in patients with IPF showed improved physical function and mobility. In this review, we will discuss our current understanding of cellular senescence, its role in age-associated diseases, with a specific focus on IPF, and potential for senotherapeutics in the treatment of fibrotic lung diseases.

Current therapy of KRAS-mutant lung cancer

KRAS mutations are the most frequent gain-of-function alterations in patients with lung adenocarcinoma (LADC) in the Western world. Although they have been identified decades ago, prior efforts to target KRAS signaling with single-agent therapeutic approaches such as farnesyl transferase inhibitors, prenylation inhibition, impairment of KRAS downstream signaling, and synthetic lethality screens have been unsuccessful. Moreover, the role of KRAS oncogene in LADC is still not fully understood, and its prognostic and predictive impact with regards to the standard of care therapy remains controversial. Of note, KRAS-related studies that included general non-small cell lung cancer (NSCLC) population instead of LADC patients should be very carefully evaluated. Recently, however, comprehensive genomic profiling and wide-spectrum analysis of other co-occurring genetic alterations have identified unique therapeutic vulnerabilities. Novel targeted agents such as the covalent KRAS G12C inhibitors or the recently proposed combinatory approaches are some examples which may allow a tailored treatment for LADC patients harboring KRAS mutations. This review summarizes the current knowledge about the therapeutic approaches of KRAS-mutated LADC and provides an update on the most recent advances in KRAS-targeted anti-cancer strategies, with a focus on potential clinical implications.

Heat-activated nanomedicine formulation improves the anticancer potential of the HSP90 inhibitor luminespib in vitro

The heat shock protein 90 inhibitor, luminespib, has demonstrated potent preclinical activity against numerous cancers. However, clinical translation has been impeded by dose-limiting toxicities that have necessitated dosing schedules which have reduced therapeutic efficacy. As such, luminespib is a prime candidate for reformulation using advanced drug delivery strategies that improve tumor delivery efficiency and limit off-target side effects. Specifically, thermosensitive liposomes are proposed as a drug delivery strategy capable of delivering high concentrations of drug to the tumor in combination with other chemotherapeutic molecules. Indeed, this work establishes that luminespib exhibits synergistic activity in lung cancer in combination with standard of care drugs such as cisplatin and vinorelbine. While our research team has previously developed thermosensitive liposomes containing cisplatin or vinorelbine, this work presents the first liposomal formulation of luminespib. The physico-chemical properties and heat-triggered release of the formulation were characterized. Cytotoxicity assays were used to determine the optimal drug ratios for treatment of luminespib in combination with cisplatin or vinorelbine in non-small cell lung cancer cells. The formulation and drug combination work presented in this paper offer the potential for resuscitation of the clinical prospects of a promising anticancer agent.

KRAS-Mutant Non-Small Cell Lung Cancer: An Emerging Promisingly Treatable Subgroup

Lung cancer, the leading cause of cancer-related deaths worldwide, can be classified into small cell lung cancer and non-small cell lung cancer (NSCLC). NSCLC is the most common histological type, accounting for 85% of all lung cancers. Kirsten rat sarcoma viral oncogene (KRAS) mutations, common in NSCLC, are associated with poor prognosis, likely due to poor responses to most systemic therapies and lack of targeted drugs. The latest published clinical trial data on new small-molecule KRAS G12C inhibitors, AMG510 and MRTX849, indicate that these molecules may potentially help treat KRAS-mutant NSCLC. Simultaneously, within the immuno-therapeutic process, immune efficacy has been observed in those patients who have KRAS mutations. In this article, the pathogenesis, treatment status, progress of immunotherapy, and targeted therapy of KRAS-mutant NSCLC are reviewed.

Identification of Predictive Biomarkers of Response to HSP90 Inhibitors in Lung Adenocarcinoma

Heat shock protein 90 (HSP90) plays an essential role in lung adenocarcinoma, acting as a key chaperone involved in the correct functioning of numerous highly relevant protein drivers of this disease. To this end, HSP90 inhibitors have emerged as promising therapeutic strategies, even though responses to them have been limited to date. Given the need to maximize treatment efficacy, the objective of this study was to use isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic techniques to identify proteins in human lung adenocarcinoma cell lines whose basal abundances were correlated with response to HSP90 inhibitors (geldanamycin and radicicol derivatives). From the protein profiles identified according to response, the relationship between lactate dehydrogenase B (LDHB) and DNA topoisomerase 1 (TOP1) with respect to sensitivity and resistance, respectively, to geldanamycin derivatives is noteworthy. Likewise, rhotekin (RTKN) and decaprenyl diphosphate synthase subunit 2 (PDSS2) were correlated with sensitivity and resistance to radicicol derivatives. We also identified a relationship between resistance to HSP90 inhibition and the p53 pathway by glucose deprivation. In contrast, arginine biosynthesis was correlated with sensitivity to HSP90 inhibitors. Further study of these outcomes could enable the development of strategies to improve the clinical efficacy of HSP90 inhibition in patients with lung adenocarcinoma.

The Effect of Heat Shock Protein 90 Inhibitor on Pain in Cancer Patients: A Systematic Review and Meta-Analysis

Background and objectives: Heat shock protein 90 (Hsp90) is a molecular chaperone that plays an essential role in tumor growth. Numerous Hsp90 inhibitors have been discovered and tested in preclinical and clinical trials. Recently, several preclinical studies have demonstrated that Hsp90 inhibitors could modulate pain sensitization. However, no studies have evaluated the impact of Hsp90 inhibitors on pain in the patients. This study aims to summarize the pain events reported in clinical trials assessing Hsp90 inhibitors and to determine the effect of Hsp90 inhibitors on pain in patients. Materials and Methods: We searched PubMed, EBSCOhost, and clinicaltrials.gov for Hsp90 inhibitor clinical trials. The pain-related adverse events were summarized. Meta-analysis was performed using the data reported in randomized controlled trials. Results: We identified 90 clinical trials that reported pain as an adverse effect, including 5 randomized controlled trials. The most common types of pain reported in all trials included headache, abdominal pain, and back pain. The meta-analysis showed that Hsp90 inhibitors increased the risk of abdominal pain significantly and appeared to increase the risk for back pain. Conclusions: In conclusion, Hsp90 inhibitor treatment could potentially increase the risk of pain. However, the meta-analysis demonstrated only moderate evidence for the connection between Hsp90 inhibitor and pain.

Mutant p53 in Cancer Progression and Targeted Therapies

TP53 is the most frequently mutated tumor suppressor gene in human cancer. The majority of mutations of p53 are missense mutations, leading to the expression of the full length p53 mutant proteins. Mutant p53 (Mutp53) proteins not only lose wild-type p53-dependent tumor suppressive functions, but also frequently acquire oncogenic gain-of-functions (GOF) that promote tumorigenesis. In this review, we summarize the recent advances in our understanding of the oncogenic GOF of mutp53 and the potential therapies targeting mutp53 in human cancers. In particular, we discuss the promising drugs that are currently under clinical trials as well as the emerging therapeutic strategies, including CRISPR/Cas9 based genome edition of mutant TP53 allele, small peptide mediated restoration of wild-type p53 function, and immunotherapies that directly eliminate mutp53 expressing tumor cells.

KRAS oncogene may be another target conquered in non-small cell lung cancer (NSCLC)

Kirsten rat sarcoma viral oncogene homolog (KRAS) is one of the most common mutant oncogenes in non‐small cell lung cancer (NSCLC). The survival of patients with KRAS mutations may be much lower than patients without KRAS mutations. However, due to the complex structure and diverse biological properties, it is difficult to achieve specific inhibitors for the direct elimination of KRAS activity, making KRAS a challenging therapeutic target. At present, with the tireless efforts of medical research, including KRAS G12C inhibitors, immunotherapy and other combination strategies, this dilemma is expected to an end. In addition, inhibition of the downstream signaling pathways of KRAS may be a promising combination strategy. Given the rapid development of treatments, understanding the details will be important to determine the individualized treatment options, including combination therapy and potential resistance mechanisms.

The survival of patients with KRAS mutations may be much lower than patients without KRAS mutations. At present, with the tireless efforts of medical research, including KRAS G12C inhibitors, immunotherapy and other combination strategy, this dilemma of KRAS mutated NSCLC is expected to an end.

HSP90 Inhibitor, 17-DMAG, Alone and in Combination with Lapatinib Attenuates Acquired Lapatinib-Resistance in ER-positive, HER2-Overexpressing Breast Cancer Cell Line

Simple Summary

Lapatinib is a tyrosine kinase inhibitor widely used as a treatment for a Human Epidermal growth factor Receptor 2 (HER2) (+) breast cancer patients. However, when resistance is acquired through continued exposure, and it is associated with a poor prognosis for patients. In this study, we identified HSP90 as a common node for acquired resistance to lapatinib in two lapatinib resistant cell lines using proteomic analysis. Notably, in vitro and in vivo studies demonstrated synergy effect between lapatinib and an HSP90 inhibitor were observed in the estrogen receptor (+) HER2 (+) breast cancer cell only. These results could be a potential strategy for future clinical trials for HSP90 inhibitors in treatment—refractory HER2 (+) metastatic cancer patients

Abstract

Lapatinib, a Human Epidermal growth factor Receptor 2 (HER2)-targeting therapy in HER2-overexpressing breast cancer, has been widely used clinically, but the prognosis is still poor because most patients acquire resistance. Therefore, we investigated mechanisms related to lapatinib resistance to evaluate new therapeutic targets that may overcome resistance. Lapatinib-resistant cell lines were established using SKBR3 and BT474 cells. We evaluated cell viability and cell signal changes, gene expression and protein changes. In the xenograft mouse model, anti-tumor effects were evaluated using drugs. Analysis of the protein interaction network in two resistant cell lines with different lapatinib resistance mechanisms showed that HSP90 protein was commonly increased. When Heat Shock Protein 90 (HSP90) inhibitors were administered alone to both resistant cell lines, cell proliferation and protein expression were effectively inhibited. However, inhibition of cell proliferation and protein expression with a combination of lapatinib and HSP90 inhibitors showed a more synergistic effect in the LR-BT474 cell line than the LR-SKBR3 cell line, and the same result was exhibited with the xenograft model. These results suggest that HSP90 inhibitors in patients with lapatinib-resistant Estrogen Receptor (ER) (+) HER2 (+) breast cancer are promising therapeutics for future clinical trials.

Making the case for EGFR TKI sequencing in EGFR mutation-positive NSCLC: a GioTag study US patient analysis

Aim: To assess time-to-treatment failure (TTF) in US patients with EGFR mutation-positive non-small-cell lung cancer (NSCLC) who received sequential afatinib-osimertinib treatment in the global, observational GioTag study. Patients & methods: Patients had EGFR T790M mutation-positive disease after first-line afatinib and subsequently received osimertinib. The primary outcome was TTF. Results: In 129 patients at US centers, median TTF was 28.4 months (90% CI: 27.0-34.1). Median overall survival was 47.6 months (90% CI: 35.5-51.5). Conclusion: Sequential afatinib-osimertinib in this US-treated population was associated with long median TTF and represents an effective, evidence-based treatment option for US patients with EGFR mutation-positive NSCLC not presenting with active brain metastases or de novo T790M. Clinical Trial Registration: NCT03370770 (ClinicalTrials.gov).

Dynamically Shaping Chaperones. Allosteric Modulators of HSP90 Family as Regulatory Tools of Cell Metabolism in Neoplastic Progression

Molecular chaperones have recently emerged as fundamental regulators of salient biological routines, including metabolic adaptations to environmental changes. Yet, many of the molecular mechanisms at the basis of their functions are still unknown or at least uncertain. This is in part due to the lack of chemical tools that can interact with the chaperones to induce measurable functional perturbations. In this context, the use of small molecules as modulators of protein functions has proven relevant for the investigation of a number of biomolecular systems. Herein, we focus on the functions, interactions and signaling pathways of the HSP90 family of molecular chaperones as possible targets for the discovery of new molecular entities aimed at tuning their activity and interactions. HSP90 and its mitochondrial paralog, TRAP1, regulate the activity of crucial metabolic circuitries, making cells capable of efficiently using available energy sources, with relevant implications both in healthy conditions and in a variety of disease states and especially cancer. The design of small-molecules targeting the chaperone cycle of HSP90 and able to inhibit or stimulate the activity of the protein can provide opportunities to finely dissect their biochemical activities and to obtain lead compounds to develop novel, mechanism-based drugs.

Alkaloids of fascaplysin are promising chemotherapeutic agents for the treatment of glioblastoma: Review

Glioblastoma is one of the most aggressive human brain tumors. Even following all the modern protocols of complex treatment, the median patient survival typically does not exceed 15 months. This review analyzes the main reasons for glioblastoma resistance to therapy, as well as attempts at categorizing the main approaches to increasing chemotherapy efficiency. Special emphasis is placed on the specific group of compounds, known as marine alkaloids and their synthetic derivatives exerting a general antitumor effect on glioblastoma cells. The unique mechanisms of marine alkaloid influence on the tumor cells prompt considering them as a promising basis for creating new chemotherapeutic agents for glioblastoma treatment.

Natural heat shock protein 90 inhibitors in cancer and inflammation

Heat shock protein (HSP)90 is the most abundant HSPs, which are chaperone molecules whose major roles are cell protection and maintenance by means of aiding the folding, the stabilization and the remodeling of a wide range of proteins. A few hundreds of proteins depend on HSP90 chaperone activity, including kinases and transcriptional factors that play essential roles in cancer and inflammation, so that HSP90-targeted therapies have been considered as a potential strategy for the treatment of cancer and inflammatory-associated diseases. HSP90 inhibition by natural, semi-synthetic and synthetic compounds have yield promising results in pre-clinical studies and clinical trials for different types of cancers and inflammation. Natural products are a huge source of biologically active compounds widely used in drug development due to the great diversity of their metabolites which are capable to modulate several protein functions. HSP90 inhibitors have been isolated from bacteria, fungi and vegetal species. These natural compounds have a noteworthy ability to modulate HSP90 activity as well as serve as scaffolds for the development of novel synthetic or semi-synthetic inhibitors. Over a hundred clinical trials have evaluated the effect of HSP90 inhibitors as adjuvant treatment against different types of tumors and, currently, new studies are being developed to gain sight on novel promising and more effective approaches for cancer treatment. In this review, we present the naturally occurring HSP90 inhibitors and analogues, discussing their anti-cancer and anti-inflammatory effects.

KNK437 restricts the growth and metastasis of colorectal cancer via targeting DNAJA1/CDC45 axis

As an inhibitor of heat shock proteins (HSPs), KNK437 has been reported to play an anti-tumor role in several cancers. But its therapeutic effect and mechanisms in colorectal cancer (CRC) remain unclear. Here, KNK437 sharply inhibited the level of DnaJ heat shock protein family (Hsp40) member A1 (DNAJA1), followed by DNAJB1, but had little effect on the levels of HSP27, HSP105, HSP90, and HSP70 in CRC cells. DNAJA1 promoted CRC cell proliferation in vitro and tumor growth and metastasis in vivo. Mechanistically, DNAJA1 was activated by E2F transcription factor 1 (E2F1) and then promoted cell cycle by stabilizing cell division cycle protein 45 (CDC45), which could be reversed by KNK437. DNAJA1 was significantly upregulated in CRC tissues and positively correlated with serosa invasion, lymph node metastasis. High level of DNAJA1 predicted poor prognosis for CRC patients. Its expression was highly linked with E2F1 and CDC45 in CRC tissues. More importantly, KNK437 significantly suppressed the growth of DNAJA1 expressing tumor in vivo. The combined treatment of KNK437 with 5-FU/L-OHP chemotherapy reduced liver metastasis of CRC. These data reveal a novel mechanism of KNK437 in anti-tumor therapy of CRC and provides a newly therapeutic strategy with potential translation to the CRC patients.

HSP90 Inhibitor Ganetespib (STA-9090) Inhibits Tumor Growth in c-Myc-Dependent Esophageal Squamous Cell Carcinoma

PURPOSE

Currently, the paucity of classical effective pharmacological drugs to treat esophageal squamous cell carcinoma (ESCC) is a major problem. The c-Myc (MYC) protein is a promising target as it is overexpressed in ESCC. MYC is a sensitive client protein of the heat shock protein 90 (HSP90) and, therefore, targeting the HSP90-MYC axis by inhibition of HSP90 is a potential therapeutic strategy for ESCC. Here, we evaluated the clinical application value of the HSP90 inhibitor (Ganetespib, STA-9090) as an anti-cancer agent for MYC-positive ESCC.

MATERIALS AND METHODS

We first analyzed ESCC tissue microarrays and clinical tissue samples to determine MYC expression. The relationship between MYC and HSP90 was analyzed by co-immunoprecipitation assays and immunofluorescence. In in vitro cell models, cell growth was analyzed using the CCK-8 kit, and MYC protein expression was analyzed by Western blot. The in vivo antitumor activity of STA-9090 was assessed in two xenograft animal models.

RESULTS

We demonstrated that MYC-overexpressing ESCC cells were highly sensitive to STA-9090 treatment through suppressing ESCC cell proliferation, cell cycle progression and survival. Moreover, STA-9090 treatment decreased MYC expression, reducing the half-life of the MYC protein. We further established two xenograft mouse models using ESCC cells and clinical ESCC samples to validate the effectiveness of STA-9090 in vivo. In both xenograft models, STA-9090 substantially inhibited the growth of MYC-positive ESCC tumors in vivo. In contrast, STA-9090 treatment demonstrated no beneficial effects in mice with low-MYC expressing ESCC tumors.

CONCLUSION

In conclusion, our data support that the HSP90 inhibitor, STA-9090, suppresses the expression of the MYC protein and interferes with HSP90-MYC protein-protein interaction. This, in turn, leads to inhibition of ESCC cell proliferation and promotion of apoptosis in ESCC cells in vitro and reduction of ESCC tumors in vivo. We propose, based on our findings, that STA-9090 is a potential novel therapeutic target for MYC-positive ESCC.

Randomized Phase III Study of Ganetespib, a Heat Shock Protein 90 Inhibitor, With Docetaxel Versus Docetaxel in Advanced Non-Small-Cell Lung Cancer (GALAXY-2)

PURPOSE

Ganetespib, a highly potent heat shock protein 90 inhibitor, blocks multiple oncogenic pathways, resulting in antitumor activity. We evaluated the combination of ganetespib and docetaxel for second-line therapy of patients with advanced adenocarcinoma of the lung.

PATIENTS AND METHODS

In this international phase III trial, patients with stage IIIB or IV adenocarcinoma diagnosed > 6 months before study entry and 1 prior systemic therapy were randomly assigned (1:1) to ganetespib 150 mg/m² on days 1 and 15 with docetaxel 75 mg/m² on day 1 of a 21-day cycle or to docetaxel alone. The primary end point was overall survival (OS).

RESULTS

Of 677 enrolled patients, 335 were randomly assigned to ganetespib and docetaxel and 337 were assigned to docetaxel. The trial was stopped early as a result of futility at a planned interim analysis. The median OS time was 10.9 months (95% CI, 9.0 to 12.3 months) in the ganetespib and docetaxel arm compared with 10.5 months (95% CI, 8.6 to 12.2 months) in docetaxel arm (hazard ratio [HR], 1.11; 95% CI, 0.899 to 1.372; P = .329). Median progression-free survival was 4.2 months in the ganetespib and docetaxel arm and 4.3 months in the docetaxel arm (HR, 1.16; 95% CI, 0.96 to 1.403; P = .119). The addition of ganetespib did not improve outcomes compared with docetaxel alone for any secondary end point, including survival in the elevated lactate dehydrogenase or EGFR and ALK wild-type populations. The most common grade 3 or 4 adverse event in both arms was neutropenia (30.9% with ganetespib and docetaxel v 25% with docetaxel).

CONCLUSION

The addition of ganetespib to docetaxel did not result in improved survival for salvage therapy of patients with advanced-stage lung adenocarcinoma.

Randomized phase III study of docetaxel plus bavituximab in previously treated advanced non-squamous non-small-cell lung cancer

Background

Bavituximab is a monoclonal antibody that targets phosphatidylserine in the presence of β2 glycoprotein 1 (β2GP1) to exert an antitumor immune response. This phase III trial determined the efficacy of bavituximab combined with docetaxel in patients with previously treated advanced non-small-cell lung cancer (NSCLC).

Patients and methods

Key eligibility criteria included advanced non-squamous NSCLC with disease progression after treatment with platinum-based doublet chemotherapy, evidence of disease control after at least two cycles of first-line therapy, presence of measurable disease, ECOG performance status 0 or 1, adequate bone marrow and organ function, and no recent history of clinically significant bleeding. Eligible patients were randomized 1 : 1 to receive up to six 21-day cycles of docetaxel plus either weekly bavituximab 3 mg/kg or placebo until progression or toxicity. The primary end point was overall survival (OS).

Results

A total of 597 patients were enrolled. Median OS was 10.5 months in the docetaxel + bavituximab arm and was 10.9 months in the docetaxel + placebo arm (HR 1.06; 95% CI 0.88-1.29; P = 0.533). There was no difference in progression-free survival (HR 1.00; 95% CI 0.82-1.22; P = 0.990). Toxicities were manageable and similar between arms. In subset analysis, among patients with high baseline serum β2GP1 levels ≥200 µg/ml, a nonsignificant OS trend favored the bavituximab arm (HR 0.82; 95% CI 0.63-1.06; P = 0.134). Among patients who received post-study immune checkpoint inhibitor therapy, OS favored the bavituximab arm (HR 0.46; 95% CI 0.26-0.81; P = 0.006).

Conclusions

The combination of bavituximab plus docetaxel is not superior to docetaxel in patients with previously treated advanced NSCLC. The addition of bavituximab to docetaxel does not meaningfully increase toxicity. The potential benefit of bavituximab observed in patients with high β2GP1 levels and in patients subsequently treated with immune checkpoint inhibitors requires further investigation.

Clinical trial number

NCT01999673.

Part I of GANNET53: A European Multicenter Phase I/II Trial of the Hsp90 Inhibitor Ganetespib Combined With Weekly Paclitaxel in Women With High-Grade, Platinum-Resistant Epithelial Ovarian Cancer-A Study of the GANNET53 Consortium

Background: Stabilized mutant p53 protein (mutp53) is a novel target in epithelial ovarian cancer. Due to aberrant conformation, mutp53 proteins depend on folding support by the Hsp90 chaperone. Hsp90 blockade induces degradation of mutp53, resulting in tumor cell cytotoxicity and increased sensitivity to chemotherapeutics. Preclinical synergy of the Hsp90 inhibitor ganetespib combined with paclitaxel provided the rationale for testing the combination in platinum-resistant ovarian cancer (PROC) patients in the GANNET53 trial (NCT02012192). Methods: Eligible patients had high-grade PROC with ≤ 4 prior lines of chemotherapy. Weekly paclitaxel (80 mg/m²) and increasing doses of ganetespib (100, 150 mg/m²) were given i.v. on days 1, 8, 15 in a 28 days cycle until disease progression or unacceptable toxicity. Endpoints were safety and determination of phase II dose. Dose limiting toxicity (DLT) was defined as grade 4 toxicity (with exceptions) occurring in cycles 1&2. Results: Ten patients (median age 59 years; range 43-70) were enrolled. No DLT occurred in cohort 1 (4 patients treated with paclitaxel + ganetespib 100 mg/m²), nor in cohorts 2 and 3 (6 patients treated with paclitaxel + ganetespib 150 mg/m²). The most common adverse event (AE) related to ganetespib was transient grade 1/2 diarrhea (n = 6). Related grade 1/2 AEs in >2 patients included QTc prolongation (n = 4), nausea (n = 3), anemia (n = 3), headache (n = 3), fatigue (n = 3), and dyspnoea (n = 3). Most frequently related grade 3/4 AEs were diarrhea (n = 3) and neutropenia (n = 2). There was 1 death on study due to hemorrhage from a duodenal ulcer. Three patients discontinued study treatment due to serious AEs (digestive hemorrhage n = 1, cardiac failure n = 1, abdominal pain and vomiting n = 1), 6 due to progressive disease, one due to investigator and patient decision. Two patients achieved a partial response (ORR 20%) and 4 patients a stable disease (disease control rate of 60%). Median PFS was 2.9 months (1.6 months in cohort 1 at 100 mg/m² ganetespib, 5.1 months in cohorts 2+3 at 150 mg/m² ganetespib). Conclusions: The combination of ganetespib 150 mg/m² with paclitaxel 80 mg/m² once weekly for 3 out of 4 weeks was generally well-tolerated with no DLTs, and therefore chosen for the randomized phase II trial.

Elevated levels of pre-treatment lactate dehydrogenase are an unfavorable predictor factor in patients with EML4-ALK rearrangement non-small cell lung cancer treated with crizotinib

Background

Targeted therapy is an important treatment for advanced non-small cell lung cancer (NSCLC) patients with specific genetic mutations, crizotinib can prolong survival in advanced NSCLC patients with echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) rearrangement. We performed a retrospective analysis to investigate the association between the lactate dehydrogenase (LDH) levels and progression-free survival (PFS) in patients with EML4-ALK rearrangement NSCLC receiving treatment with crizotinib.

Methods

Advanced (stage IIIb-IV) NSCLC patients with EML4-ALK rearrangement receiving treatment with crizotinib were enrolled between January 2007 and January 2016 at Peking Union Medical College and Cancer Hospital Chinese Academy of Medical Sciences.

Results

Overall, 212 patients were enrolled. Kaplan-Meier univariate analysis showed that elevated pre-treatment LDH level (7.9 vs 14.1 months, HR =1.251, CI: 1.008-1.553, P=0.004) was significantly associated with shorter PFS, while the post-treatment mean-LDH level (13.3 vs 14.3 months, HR=1.439, 95% CI: 0.994-2.082, P=0.970) was not significantly associated with PFS. Cox proportional hazards model also identified that pre-treatment LDH level (HR=2.085, 95% CI: 1.150-3.781, P=0.016) was associated with the PFS. Logistic regression analysis showed that post-treatment LDH level was associated with creatine kinase (OR=6.712, 95% CI 3.395-13.273, P<0.01), creatine kinase isoenzyme (OR=6.297, 95% CI 2.953-13.427, P<0.01), and hemoglobin (OR=4.163, 1.741-9.956, P<0.001).

Conclusion

An elevated pre-treatment serum LDH level (>250 U/L) was significantly associated with shorter PFS in patients with EML4-ALK rearrangement NSCLC. Post-treatment elevated serum LDH level was not significantly associated with PFS, which related to adverse events including muscle damage and anemia.

Traditional and Novel Mechanisms of Heat Shock Protein 90 (HSP90) Inhibition in Cancer Chemotherapy Including HSP90 Cleavage

HSP90 is a molecular chaperone that increases the stability of client proteins. Cancer cells show higher HSP90 expression than normal cells because many client proteins play an important role in the growth and survival of cancer cells. HSP90 inhibitors mainly bind to the ATP binding site of HSP90 and inhibit HSP90 activity, and these inhibitors can be distinguished as ansamycin and non-ansamycin depending on the structure. In addition, the histone deacetylase inhibitors inhibit the activity of HSP90 through acetylation of HSP90. These HSP90 inhibitors have undergone or are undergoing clinical trials for the treatment of cancer. On the other hand, recent studies have reported that various reagents induce cleavage of HSP90, resulting in reduced HSP90 client proteins and growth suppression in cancer cells. Cleavage of HSP90 can be divided into enzymatic cleavage and non-enzymatic cleavage. Therefore, reagents inducing cleavage of HSP90 can be classified as another class of HSP90 inhibitors. We discuss that the cleavage of HSP90 can be another mechanism in the cancer treatment by HSP90 inhibition.

Results from phase II trial of HSP90 inhibitor, STA-9090 (ganetespib), in metastatic uveal melanoma

Uveal melanoma (UM) is a rare form of melanoma without effective therapy. The biology of UM relies on several heat-shock protein 90 (Hsp90)-dependent molecules such as MET, MEK and AKT, making Hsp90 inhibition a rational approach. Patients with stage IV UM, measurable disease, and no previous chemotherapy were eligible. Patients received either ganetespib 200 mg weekly (cohort A) or 150 mg twice a week (cohort B). Primary endpoint response rate (RR) was assessed by RECIST. A total of 17 patients were accrued for this study, with seven in cohort A and 10 in cohort B. Liver metastases were present in 59%. Response outcomes included one partial response, four stable disease, 11 progressive disease, and one withdrawal for ORR: 5.9% and disease control rate of 29.4%. Progression-free survival was 1.6 months (cohort A) and 1.8 months (cohort B). Overall survival was 8.5 months (cohort A) and 4.9 months (cohort B). An overall 31% of adverse events were grade 3-4 and were mostly related to gastrointestinal toxicities. Early on-treatment (1 months) positron emission tomography showed reduction in metabolic activity in 24% of patients, suggesting a pharmacodynamic effect of Hsp90 inhibition. These early metabolic changes did not seem to be durable and/or clinically significant in relation to the 2-month response assessment. Hsp90 inhibition with ganetespib resulted in modest clinical benefit on two dosing schedules and was associated with significant, although manageable, gastrointestinal toxicity. Evidence of pharmacodynamic activity for Hsp90 inhibition was observed via positron emission tomography, which did not translate into clinical benefit, suggesting rapid development of resistance.

Luminespib plus pemetrexed in patients with non-squamous non-small cell lung cancer

BACKGROUND

Luminespib (AUY922) is a second-generation heat shock protein 90 (HSP90) inhibitor with demonstrated activity in non-small cell lung cancer (NSCLC). Since luminespib reduces levels of dihydrofolate reductase (DHFR), a key enzymatic target of pemetrexed, we assessed the safety and tolerability of luminespib in combination with pemetrexed in patients with previously treated metastatic non-squamous non-small cell lung cancer (NSCLC). We also sought to study the pharmacokinetics and correlate tumor dihydrofolate reductase (DHFR) expression with clinical response.

METHODS

Patients received weekly luminespib at either 40 mg/m², 55 mg/m², or 70 mg/m² according to a standard 3 + 3 dose-escalation design along with pemetrexed at 500 mg/m² followed by an expansion at the maximum tolerated dose (MTD).

RESULTS

Two-dose limiting toxicities (DLTs) were experienced in the 70 mg/m2 cohort, therefore the MTD was determined to be 55 mg/m². 69% (N = 9) of patients experienced ophthalmologic toxicity related to luminespib. Maximum serum concentration (Cmax) of luminespib was associated with increased grade 2 drug related adverse events (DRAEs) (r_s = 0.74, P <  0.01), with volume of distribution (V_D) inversely associated with the number of DRAEs (r_s = - 0.81, P =  0.004) and ophthalmologic related DRAEs (r_s = - 0.65, P =  0.04). The best response was partial response in one patient for 20 months, prior to expiration of all luminespib. Amongst patients treated at the MTD, the objective response rate was 14%.

CONCLUSION

In patients with previously treated metastatic NSCLC, the MTD of luminespib in combination with pemetrexed was 55 mg/m² per week. The combination of luminespib and pemetrexed demonstrated clinical activity. Tolerability of luminespib with pemetrexed is limited by ocular toxicity.

177Lu-octreotate therapy for neuroendocrine tumours is enhanced by Hsp90 inhibition

177Lu-octreotate is an FDA-approved radionuclide therapy for patients with gastroenteropancreatic neuroendocrine tumours (NETs) expressing somatostatin receptors. The 177Lu-octreotate therapy has shown promising results in clinical trials by prolonging progression-free survival, but complete responses are still uncommon. The aim of this study was to improve the 177Lu-octreotate therapy by means of combination therapy. To identify radiosensitising inhibitors, two cell lines, GOT1 and P-STS, derived from small intestinal neuroendocrine tumours (SINETs), were screened with 1,224 inhibitors alone or in combination with external radiation. The screening revealed that inhibitors of Hsp90 can potentiate the tumour cell-killing effect of radiation in a synergistic fashion (GOT1; false discovery rate <3.2×10-11). The potential for Hsp90 inhibitor ganetespib to enhance the anti-tumour effect of 177Lu-octreotate in an in vivo setting was studied in the somatostatin receptor-expressing GOT1 xenograft model. The combination led to a larger decrease in tumour volume relative to monotherapies and the tumour-reducing effect was shown to be synergistic. Using patient-derived tumour cells from eight metastatic SINETs, we could show that ganetespib enhanced the effect of 177Lu-octreotate therapy for all investigated patient tumours. Levels of Hsp90 protein expression were evaluated in 767 SINETs from 379 patients. We found that Hsp90 expression was upregulated in tumour cells relative to tumour stroma in the vast majority of SINETs. We conclude that Hsp90 inhibitors enhance the tumour-killing effect of 177Lu-octreotate therapy synergistically in SINET tumour models and suggest that this potentially promising combination should be further evaluated.

Identification and Therapeutic Intervention of Coactivated Anaplastic Lymphoma Kinase, Fibroblast Growth Factor Receptor 2, and Ephrin Type-A Receptor 5 Kinases in Hepatocellular Carcinoma

Though kinase inhibitors have been heavily investigated in the clinic to combat advanced hepatocellular carcinoma (HCC), clinical outcomes have been disappointing overall, which may be due to the absence of kinase-addicted subsets in HCC patients. Recently, strategies that simultaneously inhibit multiple kinases are increasingly appreciated in HCC treatment, yet they are challenged by the dynamic nature of the kinase networks. This study aims to identify clustered kinases that may cooperate to drive the malignant growth of HCC. We show that anaplastic lymphoma kinase, fibroblast growth factor receptor 2, and ephrin type-A receptor 5 are the essential kinases that assemble into a functional cluster to sustain the viability of HCC cells through downstream protein kinase B-dependent, extracellular signal-regulated kinase-dependent, and p38-dependent signaling pathways. Their coactivation is associated with poor prognosis for overall survival in about 13% of HCC patients. Moreover, their activities are tightly regulated by heat shock protein 90 (Hsp90). Thereby Combined kinase inhibition or targeting of heat shock protein 90 led to significant therapeutic responses both in vitro and in vivo. Conclusion: Our findings established a paradigm that highlights the cooperation of anaplastic lymphoma kinase, fibroblast growth factor receptor 2, and ephrin type-A receptor 5 kinases in governing the growth advantage of HCC cells, which might offer a conceptual "combined therapeutic target" for diagnosis and subsequent intervention in a subgroup of HCC patients.

A Phase II Study of Ganetespib as Second-line or Third-line Therapy for Metastatic Pancreatic Cancer

OBJECTIVES

Heat shock protein 90 regulates multiple signaling proteins involved in key pathways of pancreatic cancer pathogenesis. Ganetespib binds to heat shock protein 90 and interferes with its binding to client proteins thus leading to inactivation and degradation of the signaling proteins that promote cancer progression. This phase II study was designed to evaluate the efficacy of ganetespib in patients with refractory metastatic pancreatic cancer (rMPC).

METHODS

Patients with rMPC received 175 mg/m ganetespib intravenously once weekly for 3 weeks in 4-week cycles. Primary endpoint was disease control rate at 8 weeks, with a goal of 70%. Secondary endpoints were progression-free survival, overall survival, and safety. Simon's 2-stage design was used to assess futility and efficacy. Ganetespib was considered inactive if ≤8 patients among the first 15 treated had disease control after 8 weeks of treatment.

RESULTS

Fourteen patients were treated on study. Grade 3 treatment-related toxicities were diarrhea, abdominal pain, fatigue, nausea, vomiting, and hyponatremia. Disease control rate at 8 weeks was 28.6%, and median progression-free survival and overall survival were 1.58 months and 4.57 months, respectively. Early stopping rules for lack of clinical efficacy led to study closure.

CONCLUSIONS

Single-agent ganetespib was tolerable with only modest disease control in rMPC. This disease is resistant to chemotherapy, and given the emerging data in lung and rectal cancers, as well as in pancreatic cancer cell lines, suggesting improved activity of ganetespib in combination with cytotoxic agents, studies combining this agent with chemotherapy in rMPC are more likely to yield success.

Complexes formed by mutant p53 and their roles in breast cancer

Breast cancer is the most frequently diagnosed malignancy in women, and mutations in the tumor suppressor p53 are commonly detected in the most aggressive subtypes. The majority of TP53 gene alterations are missense substitutions, leading to expression of mutant forms of the p53 protein that are frequently detected at high levels in cancer cells. P53 mutants not only lose the physiological tumor-suppressive activity of the wild-type p53 protein but also acquire novel powerful oncogenic functions, referred to as gain of function, that may actively confer a selective advantage during tumor progression. Some of the best-characterized oncogenic activities of mutant p53 are mediated by its ability to form aberrant protein complexes with other transcription factors or proteins not directly related to gene transcription. The set of cellular proteins available to interact with mutant p53 is dependent on cell type and extensively affected by environmental signals, so the prognostic impact of p53 mutation is complex. Specific functional interactions of mutant p53 can profoundly impact homeostasis of breast cancer cells, reprogramming gene expression in response to specific extracellular inputs or cell-intrinsic conditions. The list of protein complexes involving mutant p53 in breast cancer is continuously growing, as is the number of oncogenic phenotypes in which they could be involved. In consideration of the functional impact of such complexes, key interactions of mutant p53 may be exploited as potential targets for development of therapies aimed at defusing the oncogenic potential of p53 mutation.

Overcoming drug-tolerant cancer cell subpopulations showing AXL activation and epithelial-mesenchymal transition is critical in conquering ALK-positive lung cancer

Anaplastic lymphoma kinase tyrosine kinase inhibitors (ALK-TKIs) induce a dramatic response in non-small cell lung cancer (NSCLC) patients with the ALK fusion gene. However, acquired resistance to ALK-TKIs remains an inevitable problem. In this study, we aimed to discover novel therapeutic targets to conquer ALK-positive lung cancer. We established three types of ALK-TKI (crizotinib, alectinib and ceritinib)-resistant H2228 NSCLC cell lines by high exposure and stepwise methods. We found these cells showed a loss of ALK signaling, overexpressed AXL with epithelial-mesenchymal transition (EMT), and had cancer stem cell-like (CSC) properties, suggesting drug-tolerant cancer cell subpopulations. Similarly, we demonstrated that TGF-β1 treated H2228 cells also showed AXL overexpression with EMT features and ALK-TKI resistance. The AXL inhibitor, R428, or HSP90 inhibitor, ganetespib, were effective in reversing ALK-TKI resistance and EMT changes in both ALK-TKI-resistant and TGF-β1-exposed H2228 cells. Tumor volumes of xenograft mice implanted with established H2228-ceritinib-resistant (H2228-CER) cells were significantly reduced after treatment with ganetespib, or ganetespib in combination with ceritinib. Some ALK-positive NSCLC patients with AXL overexpression showed a poorer response to crizotinib therapy than patients with a low expression of AXL. ALK signaling-independent AXL overexpressed in drug-tolerant cancer cell subpopulations with EMT and CSC features may be commonly involved commonly involved in intrinsic and acquired resistance to ALK-TKIs. This suggests AXL and HSP90 inhibitors may be promising therapeutic drugs to overcome drug-tolerant cancer cell subpopulations in ALK-positive NSCLC patients for the reason that ALK-positive NSCLC cells do not live through ALK-TKI therapy.

A Targeted Proteomic Approach for Heat Shock Proteins Reveals DNAJB4 as a Suppressor for Melanoma Metastasis

Heat shock proteins are molecular chaperones that are involved in protein folding. In this study, we developed a targeted proteomic method, relying on LC-MS/MS in the parallel-reaction monitoring (PRM) mode, for assessing quantitatively the human heat shock proteome. The method facilitated the coverage of approximately 70% of the human heat shock proteome and displayed much better throughput and sensitivity than the shotgun proteomic approach. We also applied the PRM method for assessing the differential expression of heat shock proteins in three matched primary/metastatic pairs of melanoma cell lines. We were able to quantify ∼45 heat shock proteins in each pair of cell lines, and the quantification results revealed that DNAJB4 is down-regulated in the three lines of metastatic melanoma cells relative to the corresponding primary melanoma cells. Interrogation of The Cancer Genome Atlas data showed that lower levels of DNAJB4 expression conferred poorer prognosis in melanoma patients. Moreover, we found that DNAJB4 suppresses the invasion of cultured melanoma cells through diminished expression and activities of matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9). Together, we established, for the first time, a high-throughput targeted proteomics method for profiling quantitatively the human heat shock proteome and discovered DNAJB4 as a suppressor for melanoma metastasis.

Ganetespib targets multiple levels of the receptor tyrosine kinase signaling cascade and preferentially inhibits ErbB2-overexpressing breast cancer cells

Although ErbB2-targeted therapeutics have significantly improved ErbB2⁺ breast cancer patient outcomes, therapeutic resistance remains a significant challenge. Therefore, the development of novel ErbB2-targeting strategies is necessary. Importantly, ErbB2 is a sensitive client protein of heat shock protein 90 (HSP90), which regulates client protein folding, maturation, and stabilization. HSP90 inhibition provides an alternative therapeutic strategy for ErbB2-targeted degradation. In particular, ganetespib, a novel HSP90 inhibitor, is a promising agent for ErbB2⁺ cancers. Nevertheless, the anti-cancer efficacy and clinical application of ganetespib for ErbB2⁺ breast cancer is largely unknown. In our study, we examined the anti-cancer effects of ganetespib on ErbB2⁺ BT474 and SKBR3 breast cancer cells, and isogenic paired cancer cell lines with lentivirus-mediated ErbB2 overexpression. Ganetespib potently inhibited cell proliferation, cell cycle progression, survival, and activation/phosphorylation of ErbB2 and key downstream effectors in ErbB2⁺ breast cancer cells. Moreover, ganetespib decreased the total protein levels of HSP90 client proteins and reduced ErbB2 protein half-life. ErbB2-overexpressing cancer cells were also more sensitive to ganetespib-mediated growth inhibition than parental cells. Ganetespib also strikingly potentiated the inhibitory effects of lapatinib in BT474 and SKBR3 cells. Ultimately, our results support the application of ganetespib-mediated HSP90 inhibition as a promising therapeutic strategy for ErbB2⁺ breast cancer.

KRAS oncogene in non-small cell lung cancer: clinical perspectives on the treatment of an old target

Lung neoplasms are the leading cause of death by cancer worldwide. Non-small cell lung cancer (NSCLC) constitutes more than 80% of all lung malignancies and the majority of patients present advanced disease at onset. However, in the last decade, multiple oncogenic driver alterations have been discovered and each of them represents a potential therapeutic target. Although KRAS mutations are the most frequently oncogene aberrations in lung adenocarcinoma patients, effective therapies targeting KRAS have yet to be developed. Moreover, the role of KRAS oncogene in NSCLC remains unclear and its predictive and prognostic impact remains controversial. The study of the underlying biology of KRAS in NSCLC patients could help to determine potential candidates to evaluate novel targeted agents and combinations that may allow a tailored treatment for these patients. The aim of this review is to update the current knowledge about KRAS-mutated lung adenocarcinoma, including a historical overview, the biology of the molecular pathways involved, the clinical relevance of KRAS mutations as a prognostic and predictive marker and the potential therapeutic approaches for a personalized treatment of KRAS-mutated NSCLC patients.

Heat-shock protein-90 prolongs septic neutrophil survival by protecting c-Src kinase and caspase-8 from proteasomal degradation

The brief lifespan of the polymorphonuclear neutrophil (PMN) is regulated through its capacity to undergo apoptosis, a constitutive process that is actively inhibited during sepsis. We sought to define the cellular mechanisms through which Heat Shock Protein 90 (Hsp90) prolongs the survival of inflammatory PMN. We evaluated Hsp90 expression and interaction with client proteins in PMNs from patients with sepsis and in healthy control PMNs treated with LPS (1 μg/mL). Hsp90 activity was inhibited pharmacologically using radicicol (Rad; 1 μM), and Hsp90 transcription was silenced in septic PMN using siRNA. PMN apoptosis was evaluated by flow cytometry and expression of cleaved caspase-8 and -3. Septic PMNs showed reduced rates of apoptosis compared with control PMNs 21 h after isolation, and Hsp90-α mRNA was significantly more abundant in septic PMN. Caspase-8 coimmunoprecipitated with Hsp90, c-Src, and the p85 inhibitory subunit of PI3K in both septic and LPS-treated PMN. Inhibition of Hsp90 activity with Rad or its translation using siRNA restored basal rates of apoptosis in both septic and LPS-treated PMN. Radicicol further reduced c-Src protein abundance, increased the ubiquitination of caspase-8 and c-Src, and enhanced the cleavage of caspase-8 and -3. We conclude that Hsp90 prolongs the survival of activated neutrophils by stabilizing a molecular complex of c-Src kinase and caspase-8, preventing their ubiquitination, and resulting in inhibition of the catalytic activity of caspase-8 and -3.

Implications of KRAS mutations in acquired resistance to treatment in NSCLC

Rationale

KRAS is the most common and, simultaneously, the most ambiguous oncogene implicated in human cancer. Despite KRAS mutations were identified in Non Small Cell Lung Cancers (NSCLCs) more than 20 years ago, selective and specific inhibitors aimed at directly abrogating KRAS activity are not yet available. Nevertheless, many therapeutic approaches have been developed potentially useful to treat NSCLC patients mutated for KRAS and refractory to both standard chemotherapy and targeted therapies.

The focus of this review will be to provide an overview of the network related to the intricate molecular KRAS pathways, stressing on preclinical and clinical studies that investigate the predictive value of KRAS mutations in NSCLC patients.

Materials and Methods

A bibliographic search of the Medline database was conducted for articles published in English, with the keywords KRAS, KRAS mutations in non-small cell lung cancer, KRAS and tumorigenesis, KRAS and TKIs, KRAS and chemotherapy, KRAS and monoclonal antibody, KRAS and immunotherapy, KRAS and drugs, KRAS and drug resistance.