Neurotoxicity of bortezomib therapy in multiple myeloma: a single-center experience and review of the literature.

Background: Bortezomib is active in heavily pretreated multiple myeloma patients; the dose-limiting toxicity is peripheral neuropathy (PN).

Methods: The authors retrospectively reviewed the incidence, severity, and risk factors for PN in 78 patients who received bortezomib. The median age was 57 years (range, 33-80 years), 62% of patients were men, and 37% of patients were African Americans.

Flavopiridol in patients with relapsed or refractory multiple myeloma: a phase 2 trial with clinical and pharmacodynamic end-points.

Flavopiridol downregulates anti-apoptotic regulators including Mcl-1, upregulates p53, globally attenuates transcription through inhibition of P-TEFb, binds to DNA, and inhibits angiogenesis. Eighteen myeloma patients were treated with 1-hour flavopiridol infusions for 3 consecutive days every 21 days. Immunoblotting for Mcl-1, Bcl-2, p53, cyclin D, phosphoRNA polymerase II and phosphoSTAT 3 was conducted on myeloma cells.

Phase II study of G3139, a Bcl-2 antisense oligonucleotide, in combination with dexamethasone and thalidomide in relapsed multiple myeloma patients.

Purpose: Bcl-2 regulates the mitochondrial apoptosis pathway that promotes chemotherapy resistance. Bcl-2 antisense oligonucleotide, G3139, targets Bcl-2 mRNA.

Patients And Methods: G3139 was administered (3 to 7 mg/kg/d for 7 days) by continuous intravenous infusion.

Phase I clinical trial of the inosine monophosphate dehydrogenase inhibitor mycophenolate mofetil (cellcept) in advanced multiple myeloma patients.

Purpose: Inosine monophosphate dehydrogenase (IMPDH) inhibitors have been used to induce leukemia blast cell differentiation but have not been tested in multiple myeloma for activity. Currently, available IMPDH inhibitor, mycophenolate mofetil (MMF), which is known as an immunosuppressant, was shown to induce apoptosis in myeloma cell lines. On the basis of our preclinical studies, we designed a clinical study to test our hypothesis that MMF has antimyeloma activity.

Bcl-2 family proteins regulate mitochondrial reactive oxygen production and protect against oxidative stress.

Bcl-2 family proteins protect against a variety of forms of cell death, including acute oxidative stress. Previous studies have shown that overexpression of the antiapoptotic protein Bcl-2 increases cellular redox capacity. Here we report that cell lines transfected with Bcl-2 paradoxically exhibit increased rates of mitochondrial H(2)O(2) generation.

Advances in biology and therapy of multiple myeloma.

Even during this past year, further advances have been made in understanding the molecular genetics of the disease, the mechanisms involved in the generation of myeloma-associated bone disease and elucidation of critical signaling pathways as therapeutic targets. New agents (thalidomide, Revimid, Velcade) providing effective salvage therapy for end-stage myeloma, have broadened the therapeutic armamentarium markedly. As evidenced in Section I by Drs.

IL-6-independent expression of Mcl-1 in human multiple myeloma.

Mcl-1 is a critical antiapoptotic survival factor for human multiple myeloma (MM). We examined the importance of IL-6 for Mcl-1 expression in five MM cell lines and in primary MM cells from 14 patients. While culture of MM.

The cyclin-dependent kinase inhibitor flavopiridol induces apoptosis in multiple myeloma cells through transcriptional repression and down-regulation of Mcl-1.

Multiple myeloma (MM) is a B-cell malignancy characterized by the accumulation of malignant plasma cells with slow proliferative rate but enhanced survival. MM cells express multiple Bcl-2 family members, including Bcl-2, Bcl-XL, and Mcl-1, which are thought to play a key role in the survival and drug resistance of myeloma. The cyclin-dependent kinase inhibitor flavopiridol has antitumor activity against hematopoietic malignancies, including CLL, in which induction of apoptosis was associated with reduced expression of antiapoptotic proteins.

Proliferation of IL-6-independent multiple myeloma does not require the activity of extracellular signal-regulated kinases (ERK1/2).

The evolutionarily conserved Ras/Raf/MEK/ERK pathway is thought to be essential for proliferation of eukaryotic cells. The human multiple myeloma (MM) cell line 8226 encodes an activated K-ras allele and proliferates without requirement for the main MM growth and survival factor IL-6. Surprisingly, the addition of the MEK1/2 inhibitors PD98059 or U0126 to 8226 cultures at doses that block virtually all ERK1/2 activity had minimal effects on the rapid proliferation of this cell line.

Myeloid cell factor-1 is a critical survival factor for multiple myeloma.

Multiple myeloma (MM) is characterized by the accumulation of malignant plasma cells in the bone marrow caused primarily by failure of normal homeostatic mechanisms to prevent the expansion of postgerminal center plasma cells. We have examined the molecular mechanisms that promote the survival of MM cells and have identified a key role for myeloid cell factor-1 (Mcl-1), an antiapoptotic member of the Bcl-2 family. These experiments were initiated by the observation that MM cells were exquisitely sensitive to culture in the presence of actinomycin D: caspase activation occurred within 3 hours of treatment and cells were not protected by interleukin-6, the main MM cell growth and survival factor.

Farnesyltransferase inhibitors reverse Ras-mediated inhibition of Fas gene expression.

Factors that govern host-tumor interaction play a critical role in tumor progression. In previous studies we have shown that oncogenic Ras inhibits the expression of Fas (CD95) and renders Ras-transformed cells resistant to Fas-induced death. We now demonstrate that culture of Ras-transformed cells in the presence of the farnesyltransferase inhibitor (FTI) LB42722 leads to up-regulation of Fas expression, both under basal growth conditions and in the presence of the inflammatory cytokines IFN-gamma and tumor necrosis factor alpha.