A phase I trial of bortezomib with temozolomide in patients with advanced melanoma: toxicities, antitumor effects, and modulation of therapeutic targets

KPT-330 and Y219 exert a synergistic antitumor effect in triple-negative breast cancer through inhibiting NF-κB signaling

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype, which has poor prognosis due to the lack of effective targeted drugs. KPT-330, an inhibitor of the nuclear export protein CRM-1, has been widely used in clinical medicine. Y219, a novel proteasome inhibitor designed by our group, shows superior efficacy, reduced toxicity, and reduced off-target effects as compared to the proteasome inhibitor bortezomib. In this study, we investigated the synergistic effect of KPT-330 and Y219 against TNBC cells, as well as the underlying mechanisms. We report that combination treatment with KPT-330 and Y219 synergistically inhibited the viability of TNBC cells in vitro and in vivo. Further analysis revealed that the combined use of KPT-330 and Y219 induced G2-M phase arrest and apoptosis in TNBC cells, and attenuated nuclear factor kappa B (NF-κB) signaling by facilitating nuclear localization of IκB-α. Collectively, these results suggest that the combined use of KPT-330 and Y219 may be an effective therapeutic strategy for the treatment of TNBC.

The role of immunotherapy and molecular‑targeted therapy in the treatment of melanoma (Review)

Skin melanomas are malignant neoplasms originating from neuroectodermal melanocytes. Compared to other neoplasms, melanomas have a high rate of growth. Their incidence is highest in Australia and New Zealand, in high‑income European countries (Switzerland, Norway, Sweden) and in the US. In Poland, the standardized incidence rate is approximately 5/100,000. Melanomas are typically highly radioresistant and chemoresistant. Before the era of immunotherapy, inoperable lesions were treated using chemotherapy based mainly on dacarbazine, temozolomide or fotemustine, which did not yield the expected results in terms of extending survival time or improving patient comfort. Therefore, there has emerged a need to seek other solutions. In most cases, the use of immunological treatment or targeted therapy has had a positive impact on survival time and relapse‑free survival. However, these periods are still relatively short, hence the need for further research and improvement of treatment. The most promising strategies appear to be antibodies that block programmed death receptor‑1 (PD‑1) and programmed death receptor ligand‑1 (PD‑L1) molecules, anti‑CTLA4 antibodies (cytotoxic T‑lymphocyte antigen 4) and therapy with BRAF and MEK inhibitors.

In vitro and in vivo efficacy of the novel oral proteasome inhibitor NNU546 in multiple myeloma

Proteasome inhibition demonstrates highly effective impact on multiple myeloma (MM) treatment. Here, we aimed to examine anti-tumor efficiency and underlying mechanisms of a novel well tolerated orally applicable proteasome inhibitor NNU546 and its hydrolyzed pharmacologically active form NNU219. NNU219 showed more selective inhibition to proteasome catalytic subunits and less off-target effect than bortezomib ex vivo. Moreover, intravenous and oral administration of either NNU219 or NNU546 led to more sustained pharmacodynamic inhibitions of proteasome activities compared with bortezomib. Importantly, NNU219 exhibited potential anti-MM activity in both MM cell lines and primary samples in vitro. The anti-MM activity of NNU219 was associated with induction of G2/M-phase arrest and apoptosis via activation of the caspase cascade and endoplasmic reticulum stress response. Significant growth-inhibitory effects of NNU219 and NNU546 were observed in 3 different human MM xenograft mouse models. Furthermore, such observation was even found in the presence of a bone marrow microenvironment. Taken together, these findings provided the basis for clinical trial of NNU546 to determine its potential as a candidate for MM treatment.

Combination therapy with F5/35 fiber chimeric conditionally replicative adenoviruses expressing IL-24 enhances the antitumor effect of temozolomide against melanoma

Background

Temozolomide (TMZ) is widely used to treat melanoma; however, response rates to TMZ are low because of rapid and frequent resistance. Conditionally, replicative adenoviruses (CRAds) are an effective and promising approach. The receptor for adenovirus is coxsackie‐adenovirus receptor (CAR), which is poorly expressed in most cells. However, CD46, which is the receptor of species B adenoviruses (Ads), is highly expressed in many cells.

Methods

We constructed CRAd F5/35‐ZD55‐IL‐24, which uses the viral receptors CAR and CD46 for entry into cells. We investigated the antitumor effect of F5/35‐ZD55‐IL‐24 in combination with TMZ to treat melanoma in vitro and in vivo.

Results

The \results indicated that F5/35‐ZD55‐IL‐24 in combination with TMZ produced additive or synergistic antitumor and pro‐apoptotic effects in melanoma cells. The combination of F5/35‐ZD55‐IL‐24 and TMZ significantly inhibited the growth of melanoma in vivo. In addition, the antitumor effect of F5/35‐ZD55‐IL‐24 was superior to that of ZD55‐IL‐24 and ZD55‐IL‐24 combined with TMZ.

Conclusions

The use of F5/35‐ZD55‐IL‐24 in conjunction with TMZ is a promising approach for anti‐melanoma therapy.

Our results indicated that F5/35‐ZD55‐IL‐24 in combination with TMZ produced additive or synergistic antitumor effect and pro‐apoptotic effect in melanoma cells highly expressed CD46. The combination of F5/35‐ZD55‐IL‐24 and TMZ significantly inhibited the growth of melanoma in vivo. We also found the antitumor effect of F5/35‐ZD55‐IL‐24 was superior to ZD55‐IL‐24, the combination of F5/35‐ZD55‐IL‐24 and TMZ had a more significant antitumor effect than ZD55‐IL‐24 combining with TMZ.

Exploring major signaling cascades in melanomagenesis: a rationale route for targetted skin cancer therapy

Although most melanoma cases may be treated by surgical intervention upon early diagnosis, a significant portion of patients can still be refractory, presenting low survival rates within 5 years after the discovery of the illness. As a hallmark, melanomas are highly prone to evolve into metastatic sites. Moreover, melanoma tumors are highly resistant to most available drug therapies and their incidence have increased over the years, therefore leading to public health concerns about the development of novel therapies. Therefore, researches are getting deeper in unveiling the mechanisms by which melanoma initiation can be triggered and sustained. In this context, important progress has been achieved regarding the roles and the impact of cellular signaling pathways in melanoma. This knowledge has provided tools for the development of therapies based on the intervention of signal(s) promoted by these cascades. In this review, we summarize the importance of major signaling pathways (mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K)-Akt, Wnt, nuclear factor κ-light-chain-enhancer of activated B cell (NF-κB), Janus kinase (JAK)-signal transducer and activator of transcription (STAT), transforming growth factor β (TGF-β) and Notch) in skin homeostasis and melanoma progression. Available and developing melanoma therapies interfering with these signaling cascades are further discussed.

MALT1 promotes melanoma progression through JNK/c-Jun signaling

Mucosa-associated lymphoma antigen 1 (MALT1) is a lymphoma oncogene that regulates signal transduction as a paracaspase and an adaptor protein. Yet, the role of MALT1 in other solid cancers such as melanoma is not well-understood. Here, we demonstrate that MALT1 is overexpressed in malignant melanoma cells, and predicts a poor disease-free survival. MALT1 inhibition via shRNA-mediated gene silencing or pharmacologically with MI-2 compound markedly reduced cell growth and migration of A2058 and A375 melanoma cell lines in vitro. Subcutaneous tumor growth analysis revealed that MALT1 gene silencing significantly reduced tumor growth and metastasis to the lung. Consistently, the subcutaneous tumors with MALT1 loss had increased cell apoptosis and decreased proliferation. In addition, these tumors showed signs of mesenchymal–epithelial transition as indicated by the upregulation of E-cadherin and downregulation of N-cadherin and β1-intergrin. Further molecular analysis revealed that MALT1 is required for c-Jun and nuclear factor-κB (NF-κB) activation by tumor necrosis factor-α. Forced expression of the c-Jun upstream activator MKK7 reversed the cell growth and migration defects caused by MALT1 loss. In contrast, NF-κB activation via expression of p65ER, a fusion protein containing NF-κB p65 and the tamoxifen-responsive mutant estrogen receptor, induced minimal effects on cell proliferation, but diminished cell death induced by MALT1 loss and TRAIL treatment. Together, these findings demonstrate that MALT1 promotes melanoma cell proliferation and motility through JNK/c-Jun, and enhances melanoma cell survival through NF-κB, underscoring MALT1 as a potential therapeutic target and biomarker for malignant melanoma.

Cell cycle-tailored targeting of metastatic melanoma: Challenges and opportunities

The advent of targeted therapies of metastatic melanoma, such as MAPK pathway inhibitors and immune checkpoint antagonists, has turned dermato-oncology from the "bad guy" to the "poster child" in oncology. Current targeted therapies are effective, although here is a clear need to develop combination therapies to delay the onset of resistance. Many antimelanoma drugs impact on the cell cycle but are also dependent on certain cell cycle phases resulting in cell cycle phase-specific drug insensitivity. Here, we raise the question: Have combination trials been abandoned prematurely as ineffective possibly only because drug scheduling was not optimized? Firstly, if both drugs of a combination hit targets in the same melanoma cell, cell cycle-mediated drug insensitivity should be taken into account when planning combination therapies, timing of dosing schedules and choice of drug therapies in solid tumors. Secondly, if the combination is designed to target different tumor cell subpopulations of a heterogeneous tumor, one drug effective in a particular subpopulation should not negatively impact on the other drug targeting another subpopulation. In addition to the role of cell cycle stage and progression on standard chemotherapeutics and targeted drugs, we discuss the utilization of cell cycle checkpoint control defects to enhance chemotherapeutic responses or as targets themselves. We propose that cell cycle-tailored targeting of metastatic melanoma could further improve therapy outcomes and that our real-time cell cycle imaging 3D melanoma spheroid model could be utilized as a tool to measure and design drug scheduling approaches.

Cell Cycle Phase-Specific Drug Resistance as an Escape Mechanism of Melanoma Cells

The tumor microenvironment is characterized by cancer cell subpopulations with heterogeneous cell cycle profiles. For example, hypoxic tumor zones contain clusters of cancer cells that arrest in G1 phase. It is conceivable that neoplastic cells exhibit differential drug sensitivity based on their residence in specific cell cycle phases. In this study, we used two-dimensional and organotypic melanoma culture models in combination with fluorescent cell cycle indicators to investigate the effects of cell cycle phases on clinically used drugs. We demonstrate that G1-arrested melanoma cells, irrespective of the underlying cause mediating G1 arrest, are resistant to apoptosis induced by the proteasome inhibitor bortezomib or the alkylating agent temozolomide. In contrast, G1-arrested cells were more sensitive to mitogen-activated protein kinase pathway inhibitor-induced cell death. Of clinical relevance, pretreatment of melanoma cells with a mitogen-activated protein kinase pathway inhibitor, which induced G1 arrest, resulted in resistance to temozolomide or bortezomib. On the other hand, pretreatment with temozolomide, which induced G2 arrest, did not result in resistance to mitogen-activated protein kinase pathway inhibitors. In summary, we established a model to study the effects of the cell cycle on drug sensitivity. Cell cycle phase-specific drug resistance is an escape mechanism of melanoma cells that has implications on the choice and timing of drug combination therapies.

Endoplasmic reticulum stress-mediated pathways to both apoptosis and autophagy: Significance for melanoma treatment

Melanoma is the most aggressive form of skin cancer. Disrupted intracellular signaling pathways are responsible for melanoma's extraordinary resistance to current chemotherapeutic modalities. The pathophysiologic basis for resistance to both chemo- and radiation therapy is rooted in altered genetic and epigenetic mechanisms that, in turn, result in the impairing of cell death machinery and/or excessive activation of cell growth and survival-dependent pathways. Although most current melanoma therapies target mitochondrial dysregulation, there is increasing evidence that endoplasmic reticulum (ER) stress-associated pathways play a role in the potentiation, initiation and maintenance of cell death machinery and autophagy. This review focuses on the reliability of ER-associated pathways as therapeutic targets for melanoma treatment.

Bortezomib Improves Adoptive T-cell Therapy by Sensitizing Cancer Cells to FasL Cytotoxicity

Cancer immunotherapy shows great promise but many patients fail to show objective responses, including in cancers that can respond well, such as melanoma and renal adenocarcinoma. The proteasome inhibitor bortezomib sensitizes solid tumors to apoptosis in response to TNF-family death ligands. Because T cells provide multiple death ligands at the tumor site, we investigated the effects of bortezomib on T-cell responses in immunotherapy models involving low-avidity antigens. Bortezomib did not affect lymphocyte or tissue-resident CD11c(+)CD8(+) dendritic cell counts in tumor-bearing mice, did not inhibit dendritic cell expression of costimulatory molecules, and did not decrease MHC class I/II-associated antigen presentation to cognate T cells. Rather, bortezomib activated NF-κB p65 in CD8(+) T cells, stabilizing expression of T-cell receptor CD3ζ and IL2 receptor-α, while maintaining IFNγ secretion to improve FasL-mediated tumor lysis. Notably, bortezomib increased tumor cell surface expression of Fas in mice as well as human melanoma tissue from a responsive patient. In renal tumor-bearing immunodeficient Rag2(-/-) mice, bortezomib treatment after adoptive T-cell immunotherapy reduced lung metastases and enhanced host survival. Our findings highlight the potential of proteasome inhibitors to enhance antitumor T-cell function in the context of cancer immunotherapy.

Myeloid IKKβ promotes antitumor immunity by modulating CCL11 and the innate immune response

Myeloid cells are capable of promoting or eradicating tumor cells and the nodal functions that contribute to their different roles are still obscure. Here, we show that mice with myeloid-specific genetic loss of the NF-κB pathway regulatory kinase IKKβ exhibit more rapid growth of cutaneous and lung melanoma tumors. In a BRAF(V600E/PTEN(-/-)) allograft model, IKKβ loss in macrophages reduced recruitment of myeloid cells into the tumor, lowered expression of MHC class II molecules, and enhanced production of the chemokine CCL11, thereby negatively regulating dendritic-cell maturation. Elevated serum and tissue levels of CCL11 mediated suppression of dendritic-cell differentiation/maturation within the tumor microenvironment, skewing it toward a Th2 immune response and impairing CD8(+) T cell-mediated tumor cell lysis. Depleting macrophages or CD8(+) T cells in mice with wild-type IKKβ myeloid cells enhanced tumor growth, where the myeloid cell response was used to mediate antitumor immunity against melanoma tumors (with less dependency on a CD8(+) T-cell response). In contrast, myeloid cells deficient in IKKβ were compromised in tumor cell lysis, based on their reduced ability to phagocytize and digest tumor cells. Thus, mice with continuous IKKβ signaling in myeloid-lineage cells (IKKβ(CA)) exhibited enhanced antitumor immunity and reduced melanoma outgrowth. Collectively, our results illuminate new mechanisms through which NF-κB signaling in myeloid cells promotes innate tumor surveillance.

A phase I trial of bortezomib and interferon-α-2b in metastatic melanoma

The possibility that cytokine administration could enhance the antitumor effects of proteasome inhibition was explored. It was found that coadministration of bortezomib and interferon-α (IFN-α) induced synergistic apoptosis in human melanoma cell lines and prolonged survival in a murine model of melanoma. A phase I study was conducted to determine the tolerability and the maximum tolerated dose of bortezomib when administered in combination with IFN-α-2b to patients with metastatic melanoma. Patients were treated on a 5-week cycle. In week 1 of cycle 1, patients received 5 million U/m(2) IFN-α subcutaneously thrice weekly. During weeks 2-4 of cycle 1, bortezomib was administered intravenously weekly along with IFN-α thrice weekly. There was a treatment break during week 5. After cycle 1, bortezomib was administered in combination with IFN-α. Bortezomib was administered in escalating doses (1.0, 1.3, or 1.6 mg/m) to cohorts of 3 patients. Sixteen patients were treated (8 women, 8 men; median age 59 y). Common grade 3 toxicities included fatigue (5), vomiting (3), and diarrhea (3). Grade 4 toxicities included fatigue (3) and lymphopenia (1). The maximum tolerated dose for bortezomib was 1.3 mg/m(2). One patient had a partial response, and 7 had stable disease. Progression-free survival was 2.5 months, and overall survival was 10.3 months. Bortezomib administration did not augment the ability of IFN-α to induce phosphorylation of STAT1 in circulating immune cells; however, it did lead to reduced plasma levels of proangiogenic cytokines. The combination of bortezomib and IFN-α can be safely administered to melanoma patients.

Phase II trial of bortezomib plus doxorubicin in hepatocellular carcinoma (E6202): a trial of the Eastern Cooperative Oncology Group

PURPOSE

To evaluate the efficacy and tolerability of bortezomib in combination with doxorubicin in patients with advanced hepatocellular carcinoma, and to correlate pharmacodynamic markers of proteasome inhibition with response and survival.

EXPERIMENTAL DESIGN

This phase II, open-label, multicenter study examined the efficacy of bortezomib (1.3 mg/m(2) IV on d1, 4, 8, 11) and doxorubicin (15 mg/m(2) IV on d1, 8) in 21-day cycles. The primary endpoint was objective response rate.

RESULTS

Best responses in 38 treated patients were 1 partial response (2.6 %), 10 (26.3 %) stable disease, and 17 (44.7 %) progressive disease; 10 patients were unevaluable. Median PFS was 2.2 months. Median OS was 6.1 months. The most common grade 3 to 4 toxicities were hypertension, glucose intolerance, ascites, ALT elevation, hyperglycemia and thrombosis/embolism. Worse PFS was seen in patients with elevated IL-6, IL-8, MIP-1α and EMSA for NF-κB at the start of treatment. Worse OS was seen in patients with elevated IL-8 and VEGF at the start of treatment. Patients had improved OS if a change in the natural log of serum MIP-1α/CCL3 was seen after treatment. RANTES/CCL5 levels decreased significantly with treatment.

CONCLUSIONS

The combination of doxorubicin and bortezomib was well-tolerated in patients with hepatocellular carcinoma, but the primary endpoint was not met. Exploratory analyses of markers of proteasome inhibition suggest a possible prognostic and predictive role and should be explored further in tumor types for which bortezomib is efficacious.

Phase I trial of bortezomib and dacarbazine in melanoma and soft tissue sarcoma

PURPOSE

Preclinical studies in human melanoma cell lines and murine xenograft tumor models suggest that the proteasome inhibitor bortezomib enhances the activity of the cytotoxic agent dacarbazine. We performed a phase I trial of bortezomib and dacarbazine in melanoma, soft tissue sarcoma, and amine precursor uptake and decarboxylation tumors. The primary objective was to identify recommended phase II doses for the combination.

EXPERIMENTAL DESIGN

Bortezomib and dacarbazine were both administered intravenously once weekly. All patients received prophylactic antiemetics. Dose escalation proceeded using a standard 3 + 3 design. Response was assessed according to NCI RECIST v1.0.

RESULTS

Twenty eight patients were enrolled to six dose levels. Bortezomib 1.6 mg/m(2) and dacarbazine 580 mg/m(2) are the recommended phase II weekly doses. The combination was generally well tolerated. Among 15 patients with melanoma there was one durable complete response in a patient with an exon-11 cKIT mutation, and one partial response. Among 12 patients with soft tissue sarcoma there was one partial response.

CONCLUSIONS

Bortezomib 1.6 mg/m(2) and dacarbazine 580 mg/m(2) administered intravenously once weekly is well tolerated and has at least minimal activity in melanoma and soft tissue sarcoma.

HDAC inhibitor L-carnitine and proteasome inhibitor bortezomib synergistically exert anti-tumor activity in vitro and in vivo

Combinations of proteasome inhibitors and histone deacetylases (HDAC) inhibitors appear to be the most potent to produce synergistic cytotoxicity in preclinical trials. We have recently confirmed that L-carnitine (LC) is an endogenous HDAC inhibitor. In the current study, the anti-tumor effect of LC plus proteasome inhibitor bortezomib (velcade, Vel) was investigated both in cultured hepatoma cancer cells and in Balb/c mice bearing HepG2 tumor. Cell death and cell viability were assayed by flow cytometry and MTS, respectively. Gene, mRNA expression and protein levels were detected by gene microarray, quantitative real-time PCR and Western blot, respectively. The effect of Vel on the acetylation of histone H3 associated with the p21(cip1) gene promoter was examined by using ChIP assay and proteasome peptidase activity was detected by cell-based chymotrypsin-like (CT-like) activity assay. Here we report that (i) the combination of LC and Vel synergistically induces cytotoxicity in vitro; (ii) the combination also synergistically inhibits tumor growth in vivo; (iii) two major pathways are involved in the synergistical effects of the combinational treatment: increased p21(cip1) expression and histone acetylation in vitro and in vivo and enhanced Vel-induced proteasome inhibition by LC. The synergistic effect of LC and Vel in cancer therapy should have great potential in the future clinical trials.

Phase 1 clinical trial of the novel proteasome inhibitor marizomib with the histone deacetylase inhibitor vorinostat in patients with melanoma, pancreatic and lung cancer based on in vitro assessments of the combination

PURPOSE

Combining proteasome and histone deacetylase (HDAC) inhibition has been seen to provide synergistic anti-tumor activity, with complementary effects on a number of signaling pathways. The novel bi-cyclic structure of marizomib with its unique proteasome inhibition, toxicology and efficacy profiles, suggested utility in combining it with an HDAC inhibitor such as vorinostat. Thus, in this study in vitro studies assessed the potential utility of combining marizomib and vorinostat, followed by a clinical trial with the objectives of assessing the recommended phase 2 dose (RP2D), pharmacokinetics (PK), pharmacodynamics (PD), safety and preliminary anti-tumor activity of the combination in patients.

EXPERIMENTAL DESIGN

Combinations of marizomib and vorinostat were assessed in vitro. Subsequently, in a Phase 1 clinical trial patients with melanoma, pancreatic carcinoma or Non-small Cell Lung Cancer (NSCLC) were given escalating doses of weekly marizomib in combination with vorinostat 300 mg daily for 16 days in 28 day cycles. In addition to standard safety studies, proteasome inhibition and pharmacokinetics were assayed.

RESULTS

Marked synergy of marizomib and vorinostat was seen in tumor cell lines derived from patients with NSCLC, melanoma and pancreatic carcinoma. In the clinical trial, 22 patients were enrolled. Increased toxicity was not seen with the combination. Co-administration did not appear to affect the PK or PD of either drug in comparison to historical data. Although no responses were demonstrated using RECIST criteria, 61% of evaluable patients demonstrated stable disease with 39% having decreases in tumor measurements.

CONCLUSIONS

Treatment of multiple tumor cell lines with marizomib and vorinostat resulted in a highly synergistic antitumor activity. The combination of full dose marizomib with vorinostat is tolerable in patients with safety findings consistent with either drug alone.

Metastatic melanoma - a review of current and future drugs

Background:

Melanoma is one of the most aggressive cancers, and it is estimated that 76,250 men and women will be diagnosed with melanoma of the skin in the USA in 2012. Over the last few decades many drugs have been developed but only in 2011 have new drugs demonstrated an impact on survival in metastatic melanoma.

Methods:

A systematic search of literature was conducted, and studies providing data on the effectiveness of current and/or future drugs used in the treatment of metastatic melanoma were selected for review. This review discusses the advantages and limitations of these agents, evaluating past, current and future clinical trials designed to overcome such limitations.

Results:

To date, there are four drugs approved by the Food and Drug Administration for melanoma (dacarbazine, interleukin-2, ipilimumab and vemurafenib). Despite efforts to develop new drugs, few of them have demonstrated any clinical benefits. Approved in 1975, dacarbazine remains the gold standard in chemotherapy, although ipilimumab and vemurafenib have raised many hopes in the last few years. Combining dacarbazine or other chemotherapy agents with new pharmacological agents may be a new way to achieve better clinical responses in patients with metastatic melanoma.

Discussion:

Advances in the molecular knowledge of melanoma have led to major improvements in the treatment of patients with metastatic melanoma, providing new targets and insights. However, heterogeneity amongst study populations, different approaches to treatment and the different melanoma types and localisations included in the trials makes their comparison difficult. New studies focusing on drugs developed in recent decades are warranted.

NF-κB as potential target in the treatment of melanoma

The RAS/MAP kinase pathway has attracted attention because activating mutations of the BRAF serine/threonine kinase was described in over 50% of melanomas. Very recently, selective and potent BRAF inhibitors have been developed. Several other signal transduction pathways have been found to be constitutively active or mutated in other subsets of melanoma tumors that are potentially targetable with new agents. Among these, NFκB is another pathway that melanoma tumors use to achieve survival, proliferation and resistance to apoptosis. Inhibition of NF-κB activation appears to be a very promising option for anti-cancer therapies.

New therapeutic targets in melanoma

Research into molecular targets for drug development in melanoma is starting to bear fruit. Of the drugs tested to date in patients with metastatic melanoma, those that have yielded the best results are V600E BRAF inhibitors in melanomas carrying the V600E mutation; c-kit tyrosine kinase activity inhibitors in melanomas carrying c-kit mutations; and anti-cytotoxic T lymphocyte antigen 4 (CTLA-4) antibodies, which block the mechanisms involved in immune tolerance. Many problems have yet to be resolved in these areas, however, such as the rapid development of resistance to BRAF and c-kit inhibitors and the lack of biomarkers to predict treatment response in the case of CTLA-4 blockers. We review the results of targeted therapy with these and other drugs in metastatic melanoma and discuss what the future holds for this field.

A phase I study of bortezomib and temozolomide in patients with advanced solid tumors

PURPOSE

The primary objective was to determine the maximum tolerated doses (MTDs) of the combination of bortezomib and temozolomide in patients with solid tumors. The secondary objective was to evaluate the pharmacokinetics (PK) of bortezomib with and without concurrent hepatic enzyme-inducing anticonvulsants (HEIAs).

METHODS

Bortezomib was administered on days 2, 5, 9, and 12; temozolomide on days 1-5 of a 28-day cycle. Dose escalation proceeded using a standard 3+3 design. Patients with primary or metastatic brain tumors were eligible and were stratified based on whether they were taking HEIAs or not.

RESULTS

Of the 25 patients enrolled, 22 were not taking HEIAs. MTDs were only given to patients not receiving HEIAs. Dose-limiting toxicities (DLTs) consisted of grade-3 constipation, hyponatremia, fatigue, elevated hepatic enzymes, and grade-4 neutropenia, thrombocytopenia, constipation, and abdominal pain. Stable disease (>8 weeks) was observed in 5 patients. Bortezomib systemic clearance (CL(sys)) on day 9 was 51% of the CL(sys) on day 2 (P < 0.01) Similarly, the normalized area under the concentration-time curve (norm AUC) on day 9 was 1.9 times the norm AUC on day 2 (P < 0.01). The median bortezomib CL(sys) on days 2 and 9 was significantly higher (P < 0.04) in patients taking HEIAs, and the median norm AUC was correspondingly lower (P < 0.04).

CONCLUSIONS

The MTDs for the combination of bortezomib and temozolomide in patients not taking HEIAs are 1.3 and 200 mg/m(2), respectively. The rate of bortezomib elimination in patients taking HEIAs was increased twofold. Additional trials are needed to better define the optimal dosing in such patients.

Virus reactivation: a panoramic view in human infections

Viruses are obligate intracellular parasites, relying to a major extent on the host cell for replication. An active replication of the viral genome results in a lytic infection characterized by the release of new progeny virus particles, often upon the lysis of the host cell. Another mode of virus infection is the latent phase, where the virus is 'quiescent' (a state in which the virus is not replicating). A combination of these stages, where virus replication involves stages of both silent and productive infection without rapidly killing or even producing excessive damage to the host cells, falls under the umbrella of a persistent infection. Reactivation is the process by which a latent virus switches to a lytic phase of replication. Reactivation may be provoked by a combination of external and/or internal cellular stimuli. Understanding this mechanism is essential in developing future therapeutic agents against viral infection and subsequent disease. This article examines the published literature and current knowledge regarding the viral and cellular proteins that may play a role in viral reactivation. The focus of the article is on those viruses known to cause latent infections, which include herpes simplex virus, varicella zoster virus, Epstein-Barr virus, human cytomegalovirus, human herpesvirus 6, human herpesvirus 7, Kaposi's sarcoma-associated herpesvirus, JC virus, BK virus, parvovirus and adenovirus.

Transcription alterations of members of the ubiquitin-proteasome network in prostate carcinoma

The purpose of this work was to investigate the role of the ubiquitin-proteasome network (UPN) in prostate cancer (PCA) and to elicit potential markers for this disease. The UPN represents a key factor in the maintenance of cellular homoeostasis as a result of its fundamental function in the regulation of intracellular protein degradation. Members of this network have a role in the biology of haematological and solid tumours. Tumour cells and normal epithelial cells from 22 prostatectomy specimens were isolated by laser microdissection. Prostate biopsy samples from healthy individuals served for technical calibration and as controls. Transcript levels of eight selected genes with E3 ubiquitin ligase activity (labelling target proteins for proteasome degradation) and two genes belonging to the proteasome-multienzyme complex itself were analysed by quantitative real-time RT-PCR. The proteasome genes PSMC4 and PSMB5 and the E3 ubiquitin ligase NEDD4L were significantly and coherently upregulated in PCA cells compared with the corresponding adjacent normal prostate tissue. Transcription of the E3 ubiquitin ligase SMURF2 was significantly higher in organ-confined tumours (pT2) compared with non-organ-confined cancers (pT3). The results indicate a role for PSMC4 and PSMB5 and the E3 ubiquitin ligase NEDD4L in prostate tumourigenesis, whereas SMURF2 downregulation could be associated with clinical progression. NEDD4L and SMURF2 both target transforming growth factor (TGF)-β for degradation. This reflects the pleiotropic role of the TGF-β signalling pathway acting as a tumour suppressor in normal and pre-cancerous cells, but having oncogenic properties in progressing cancer. Further studies have to elucidate whether these alterations could represent clinically relevant PCA-diagnostic and progression markers.

Diagnostic value and prognostic significance of plasmatic proteasome level in patients with melanoma

Plasmatic proteasome (p-proteasome) also called circulating proteasome has recently been described as a tumor marker. We investigated the diagnostic and prognostic accuracies of p-proteasome levels in a melanoma population classified according to the American Joint Committee on Cancer staging system. Using an ELISA test, we measured p-proteasome levels in 90 patients and 40 controls between March 2003 and March 2008. The subunit composition of p-proteasomes was determined in metastatic melanoma by proteomic analysis. The mean p-proteasome levels were correlated with stages (P < 0.0001; r(S) = 0.664). They were significantly higher in patients with stage IV and stage III with lymph node metastasis (9187 ± 1294 and 5091 ± 454 ng/ml, respectively) compared to controls (2535 ± 187 ng/ml; P < 0.001), to stage I/II (2864 ± 166 ng/ml; P < 0.001) and to stage III after curative lymphadenectomy (2859 ± 271 ng/ml; P < 0.001). The diagnostic accuracy of p-proteasome was evaluated by receiver operating characteristic analysis. With a cut-off of 4300 ng/ml, diagnostic specificity and sensitivity of p-proteasome for regional or visceral metastases were respectively 96.3% and 72.2%. In univariate analysis, high p-proteasome levels (>4300 ng/ml) were significantly correlated with an increased risk of progression [hazard ratio (HR) = 7.34; 95% CI 3.54-15.21, P < 0.0001] and a risk of death (HR = 5.92; 95% CI 2.84-12.33, P < 0.0001). In multivariate analysis, high p-proteasome levels were correlated with a poorer clinical outcome in the subgroup analysis limited to patients with disease stages I, II and III. Proteomic analysis confirmed the presence of all proteasome and immunoproteasome subunits. Taken together, these results indicate that p-proteasomes are a new marker for metastatic dissemination in patients with melanoma.

Systemic therapy of non-resectable metastatic melanoma

In advanced metastatic melanoma (non-resectable stage III/IV), the prognosis still remains poor, with median survival times between six and twelve months. Systemic therapeutic approaches for metastatic melanoma include chemotherapy, immunotherapy, immunochemotherapy, small molecules and targeted therapy. In this review, we will focus on the various treatment modalities as well as new agents used for targeted therapy.

Inhibition of NF-κB signaling as a strategy in disease therapy

As described extensively in this issue, NF-κB transcription factors regulate a number of important physiological processes, including inflammation and immune responses, cell growth and survival, and the expression of certain viral genes. Moreover, NF-κB activity is elevated in and contributes to the pathology of several human diseases, including many cancers and chronic inflammatory diseases. Therefore, there has been great interest in the characterization and development of methods to limit NF-κB signaling for pharmacological intervention. This article describes some of the approaches that have been employed to inhibit NF-κB using in vitro and in vivo experimental models. Moreover, some examples of the clinical use of NF-κB inhibitors are discussed, primarily for the treatment of two B-cell malignancies, multiple myeloma and diffuse large B-cell lymphoma. Finally, the rationale and strategies for inhibiting specific NF-κB subunit activity for disease therapy are discussed.