Stem cell-associated heterogeneity in Glioblastoma results from intrinsic tumor plasticity shaped by the microenvironment

The identity and unique capacity of cancer stem cells (CSC) to drive tumor growth and resistance have been challenged in brain tumors. Here we report that cells expressing CSC-associated cell membrane markers in Glioblastoma (GBM) do not represent a clonal entity defined by distinct functional properties and transcriptomic profiles, but rather a plastic state that most cancer cells can adopt. We show that phenotypic heterogeneity arises from non-hierarchical, reversible state transitions, instructed by the microenvironment and is predictable by mathematical modeling. Although functional stem cell properties were similar in vitro, accelerated reconstitution of heterogeneity provides a growth advantage in vivo, suggesting that tumorigenic potential is linked to intrinsic plasticity rather than CSC multipotency. The capacity of any given cancer cell to reconstitute tumor heterogeneity cautions against therapies targeting CSC-associated membrane epitopes. Instead inherent cancer cell plasticity emerges as a novel relevant target for treatment.publishedVersio

Prevention of docetaxel- or paclitaxel-associated taste alterations in cancer patients with oral glutamine : a randomized, placebo-controlled, double-blind study

Taste alteration (dysgeusia), an underrecognized toxicity associated with taxane-based chemotherapy (TaxCh), lacks standard treatment. We investigated prevention of dysgeusia with oral glutamine in patients undergoing first-time TaxCh. Adult patients were randomized to receive either 30 g/day glutamine or placebo (maltodextrin) from day 1 of TaxCh. Dysgeusia was measured daily with a visual analogue scale (VAS). On each chemotherapy cycle, objective (sour, sweet, salty, bitter) and subjective (four-category scale) taste and toxicity (National Cancer Institute Common Toxicity Criteria, v.3) were assessed. Stomatitis and zinc deficiency were treated. For primary outcomes, repeated dysgeusia scores were analyzed with a linear mixed model. Repeated data on each objective or subjective taste item were analyzed with a generalized estimating equation. Of 52 patients randomized, 41 completed treatment (median study duration, 74 days). At baseline, the glutamine (n = 21) and placebo (n = 20) groups were comparable for age (64 years), gender (32% men), tumor types, chemotherapy (docetaxel, 44%; paclitaxel, 56%), schedule (weekly, 78%; 3-weekly, 22%), treatment intention (15% adjuvant), dysgeusia (VAS, 11/100), and taste recognition (88%). Twenty-four patients had peripheral neuropathy grades 1-2; none had grade 3. Glutamine and placebo were not different for maximal dysgeusia and increase from baseline, with an insignificant linear time effect. Separate subgroup analyses for patients with baseline dysgeusia > or =11 or <11 did not alter the results. Objective or subjective taste tests were not different, neither were adverse events. Compared with placebo, oral glutamine did not prevent or decrease subjective taste disturbances or altered taste perception associated with TaxCh. The role of glutamine in supportive care of taxane-associated dysgeusia seems limited

Stem cell-associated heterogeneity in Glioblastoma results from intrinsic tumor plasticity shaped by the microenvironment

The identity and unique capacity of cancer stem cells (CSC) to drive tumor growth and resistance have been challenged in brain tumors. Here we report that cells expressing CSC-associated cell membrane markers in Glioblastoma (GBM) do not represent a clonal entity defined by distinct functional properties and transcriptomic profiles, but rather a plastic state that most cancer cells can adopt. We show that phenotypic heterogeneity arises from non-hierarchical, reversible state transitions, instructed by the microenvironment and is predictable by mathematical modeling. Although functional stem cell properties were similar in vitro, accelerated reconstitution of heterogeneity provides a growth advantage in vivo, suggesting that tumorigenic potential is linked to intrinsic plasticity rather than CSC multipotency. The capacity of any given cancer cell to reconstitute tumor heterogeneity cautions against therapies targeting CSC-associated membrane epitopes. Instead inherent cancer cell plasticity emerges as a novel relevant target for treatment

Stem cell-associated heterogeneity in Glioblastoma results from intrinsic tumor plasticity shaped by the microenvironment

The identity and unique capacity of cancer stem cells (CSC) to drive tumor growth and resistance have been challenged in brain tumors. Here we report that cells expressing CSC-associated cell membrane markers in Glioblastoma (GBM) do not represent a clonal entity defined by distinct functional properties and transcriptomic profiles, but rather a plastic state that most cancer cells can adopt. We show that phenotypic heterogeneity arises from non-hierarchical, reversible state transitions, instructed by the microenvironment and is predictable by mathematical modeling. Although functional stem cell properties were similar in vitro, accelerated reconstitution of heterogeneity provides a growth advantage in vivo, suggesting that tumorigenic potential is linked to intrinsic plasticity rather than CSC multipotency. The capacity of any given cancer cell to reconstitute tumor heterogeneity cautions against therapies targeting CSC-associated membrane epitopes. Instead inherent cancer cell plasticity emerges as a novel relevant target for treatment

Dendritic cell-based multi-epitope immunotherapy of hormone-refractory prostate carcinoma

Background: Dendritic cell (DC)-based immunotherapy is a promising approach to augment tumor antigen-specific T cell responses in cancer patients. However, tumor escape with down-regulation or complete loss of target antigens may limit the susceptibility of tumor cells to the immune attack. Concomitant generation of T cell responses against several immunodominant antigens may circumvent this potential drawback. In this trial, we determined the immunostimulatory capacity of autologous DC pulsed with multiple T cell epitopes derived from four different prostate-specific antigens in patients with advanced hormone-refractory prostate cancer.Patients and methods:Autologous DC of HLA-A*0201+ patients with hormone-refractory prostate cancer were loaded with antigenic peptides derived from prostate stem cell antigen (PSCA14–22), prostatic acid phosphatase (PAP299–307), prostate-specific membrane antigen (PSMA4–12), and prostate-specific antigen (PSA154–163). DC were intradermally applied six times at biweekly intervals followed-in the case of an enhanced immune response-by monthly booster injections. Immune monitoring during the time of ongoing vaccinations (12–59 weeks) included ex vivo ELISPOT measurements, MHC tetramer analysis and in vitro cytotoxicity assays.Results: Of the initial six patients, three qualified for long-term multi-epitope DC vaccination. This regime was tolerated well by all three patients. The vaccination elicited significant cytotoxic T cell responses against all prostate-specific antigens tested. In addition, memory T cell responses against the control peptides derived from influenza matrix protein and tetanus toxoid were efficiently boosted. Clinically, the long-term DC vaccination was associated with an increase in PSA doubling time.Conclusions: DC-based multi-epitope immunotherapy with repeated boosting in men with hormonerefractory prostate carcinoma is feasible and generates efficient cellular antitumor responses