Repurposing proteasome inhibitors for improved treatment of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is associated with poor prognosis and limited treatment options due to the lack of important receptors (estrogen receptor [ER], progesterone receptor [PR], and human epidermal growth factor receptor 2 [HER2]) used for targeted therapy. However, high-throughput in vitro drug screening of cell lines is a powerful tool for identifying effective drugs for a disease. Here, we determine the intrinsic chemosensitivity of TNBC cell lines to proteasome inhibitors (PIs), thereby identifying potentially potent 2-drug combinations for TNBC. Eight TNBC cell lines (BT-549, CAL-148, HCC1806, HCC38, HCC70, MDA-MB-436, MDA-MB-453, and MDA-MB-468) and two controls (MCF-10A and MCF-7) were first exposed to 18 drugs (11 PIs and 7 clinically relevant chemotherapeutic agents) as monotherapy, followed by prediction of potent 2-drug combinations using the IDACombo pipeline. The synergistic effects of the 2-drug combinations were evaluated with SynergyFinder in four TNBC cell lines (CAL-148, HCC1806, HCC38, and MDA-MB-468) and three controls (BT-474, MCF-7, and T47D) in vitro, followed by further evaluation of tumor regression in zebrafish tumor models established using HCC1806 and MCF-7 cells. Monotherapy identified nine effective drugs (bortezomib, carfilzomib, cisplatin, delanzomib, docetaxel, epoxomicin, MLN-2238, MLN-9708, and nedaplatin) across all cell lines. PIs (e.g., bortezomib, delanzomib, and epoxomicin) were highly potent drugs in TNBC cells, of which bortezomib and delanzomib inhibited the chymotrypsin-like activity of the 20 S proteasome by 100% at 10 µM. Moreover, several potent 2-drug combinations (e.g., bortezomib+nedaplatin and epoxomicin+epirubicin) that killed virtually 100% of cells were also identified. Although HCC1806- and MCF-7-derived xenografts treated with bortezomib+nedaplatin and carboplatin+paclitaxel were smaller, HCC1806 cells frequently metastasized to the trunk region. Taken together, we show that PIs used in combination with platinum agents or topoisomerase inhibitors exhibit increased efficiency with almost 100% inhibition in TNBC cell lines, indicating that PIs are therefore promising compounds to use as combination therapy for TNBC.

Dietary Fiber and the Hippocampal Neurogenic Niche in a Model of Pelvic Radiotherapy

We sought to determine whether radiation to the colorectum had an impact on parameters of hippocampal neurogenesis and, if so, whether it could be modulated by a fiber-rich diet. Male C57BL/6J mice were fed a diet containing bioprocessed oat bran or a fiber-free diet, starting two weeks before colorectal irradiation with 4 fractions of 8 Gray or sham-irradiation. Diets were then continued for 1, 6 or 18 weeks, whereafter parameters of hippocampal neurogenesis were analyzed and correlated to serum cytokine levels. No statistically significant changes in neuronal markers or cell proliferation were found at one week post-irradiation. Six weeks post-irradiation there was a decreased cell proliferation in the subgranular zone that appeared slightly more pronounced in irradiated animals on a fiber-free diet and increased numbers of immature neurons per mm² dentate gyrus in the irradiated mice, with a statistically significant increase in mice on a fiber-rich diet. Microglial abundancy was similar between all groups. 18 weeks post-irradiation, a fiber-free diet had reduced the number of immature neurons, whereas irradiation resulted in an increase. Despite this, the population of mature neurons was stable. Analysis of serum cytokines revealed a negative correlation between MIP1-α and the number of immature neurons one week after irradiation, regardless of diet. Our findings show that pelvic radiotherapy has the potential to cause a long-lasting impact on hippocampal neurogenesis, and dietary interventions may modulate this impact. More in-depth studies on the relationship between irradiation-induced intestinal injury and brain health are warranted.

SoxD transcription factor deficiency in Schwann cells delays myelination in the developing peripheral nervous system

The three SoxD proteins, Sox5, Sox6 and Sox13, represent closely related transcription factors with important roles during development. In the developing nervous system, SoxD proteins have so far been primarily studied in oligodendroglial cells and in interneurons of brain and spinal cord. In oligodendroglial cells, Sox5 and Sox6 jointly maintain the precursor state, interfere with terminal differentiation, and thereby ensure the proper timing of myelination in the central nervous system. Here we studied the role of SoxD proteins in Schwann cells, the functional counterpart of oligodendrocytes in the peripheral nervous system. We show that Schwann cells express Sox5 and Sox13 but not Sox6. Expression was transient and ceased with the onset of terminal differentiation. In mice with early Schwann cell-specific deletion of both Sox5 and Sox13, embryonic Schwann cell development was not substantially affected and progressed normally into the promyelinating stage. However, there was a mild and transient delay in the myelination of the peripheral nervous system of these mice. We therefore conclude that SoxD proteins—in stark contrast to their action in oligodendrocytes—promote differentiation and myelination in Schwann cells.

The Tyrosine Kinase Pyk2 Contributes to Complement-Mediated Phagocytosis in Murine Macrophages

Proline-rich tyrosine kinase 2 (Pyk2) is a member of the focal adhesion kinase (FAK) family and is mainly expressed in neuronal and hematopoietic cells. As FAK family members are involved in signaling connections downstream of integrins, we studied the role of Pyk2 in complement-receptor 3 (CR3, also known as Mac-1, integrin αMβ2, CD11b/CD18)-mediated phagocytosis, a key process in innate immunity. Using 3 independent approaches, we observed that Pyk2 contributes to CR3-dependent phagocytosis by RAW 264.7 macrophages, but is dispensable for Fcγ receptor (FcγR)-mediated uptake. Reduction of Pyk2 expression levels via siRNA, the pharmacological inhibition of Pyk2 kinase activity as well as macrophage treatment with a cell permeable TAT fusion protein containing the C-terminus of Pyk2 (TAT-PRNK) significantly impaired CR3-mediated phagocytosis without affecting FcγR-mediated uptake. In addition, Pyk2 was strongly recruited to complement opsonized Escherichia coli and the pharmacological inhibition of Pyk2 significantly decreased uptake of the bacteria. Finally, CRISPR/Cas-mediated disruption of the pyk2 gene in RAW 264.7 macrophages confirmed the role of this protein tyrosine kinase in CR3-mediated phagocytosis. Together, our data demonstrate that Pyk2 selectively contributes to the coordination of phagocytosis-promoting signals downstream of CR3, but is dispensable for FcγR-mediated phagocytosis.

Sexual problems of male patients in family practice

OBJECTIVES

Little is known about men's expectations of their family physicians regarding sexual disorders. Our goal was to evaluate the frequency of sexual problems among male patients in family practice and to assess their need for help.

STUDY DESIGN

We performed a cross-sectional survey based on structured questionnaires answered by patients and physicians in German family practices.

POPULATION

We approached 43 family physicians; 20 (43%) participated. On a single day all men 18 years and older visiting the participating practices were approached, and 307 (84%) took part in the survey.

OUTCOMES MEASURED

Patients were asked about their frequency and type of sexual problems, their need for help, and their expectations of their physicians. The physicians described their perceptions and management of sexual problems in family practice.

RESULTS

Nearly all patients (93%) reported at least 1 sexual problem from which they suffered seldom or more often. The most common problems were low sexual desire (73%) and premature ejaculation (66%). Occupational stress was considered causative by more than half of the men (107/201). Forty-eight percent considered it important to talk with their physicians about sexual concerns. However, most physicians initiated a discussion about sexual concerns only seldom or occasionally. There was a nonsignificant correlation between the physicians' assumed knowledge and the patients' wish to contact them in case of sexual problems (rho=0.26).

CONCLUSIONS

The high frequency of self-reported sexual disorders and the hesitancy of family physicians to deal with this topic signals a neglected area in primary health care. Certain conditions, such as occupational stress, which may be associated with sexual concerns, should encourage the physician to initiate discussions about sexuality.

German family physicians' attitudes toward care of involuntarily childless patients

BACKGROUND AND OBJECTIVES

Many family physicians regard fertility counseling out of their scope of practice, although key elements in the care of involuntarily childless couples fall within the theoretical framework of family practice. This study analyzed the doctors' value system concerning the care of infertile patients and whether a personal interview leads to a greater sensitivity toward fertility issues.

METHODS

We conducted 57 baseline and 51 follow-up interviews with family physicians in the area of Göttingen, Germany. We performed quantitative and qualitative analyses.

RESULTS

During the baseline interview, all family physicians placed involuntary childlessness within the domain of fertility specialists or regarded it as patients' private matter. Fourteen family physicians (27%) considered fertility counseling more important at the follow-up interview than at the time of the baseline interview. Judgmental views of infertile couples could be detected in both interviews. More than one third of the family physicians assumed a connection between the patients' childlessness and their personal behavior or way of living. Although the majority (73%) of the family physicians regarded involuntary childlessness as a disease and considered assisted conception techniques as legitimate, a recommendation for fee reimbursement for fertility services was rejected by more than half of the physicians.

CONCLUSIONS

Most German family physicians do not consider that care of involuntarily childless couples is within or appropriate to their scope of practice.

Comparing women's views on family and sexual problems in family and gynecological practices

This study compares the role of community gynecologists and family physicians, seen from the patients' perspective. A sample of 126 female patients in family practices and 212 patients in gynecological practices were surveyed about their preferences and expectations of whether their doctor should address personal, family and sexual problems. The effects of covariates (such as the type of doctor, patient age, family status, child desire) on patient expectations were simultaneously assessed by multiple logistic regression. Between 40% and 70% of the patients contacted confirmed the family-oriented approach, both in family practices and gynecological practices. Family practice patients more frequently stressed their doctor's knowledge of personal and family aspects (odds ratio [OR] = 1.7, 95% confidence interval [95% CI] = 1.1-2.7); whereas communication about sexual problems and a possible desire to have a child was more often considered as the gynecologist's domain (OR = 2.8 [95% CI = 1.8-4.4] and OR = 1.8 [95% CI = 1.1-2.8], respectively). Female patients older than 30 years were more often interested in communication on family related affairs (OR = 2.2, 95% CI = 1.4-3.4). These data illustrate that many patients would like both their community gynecologist and their family physician to take notice of their personal and family life conditions, including sexual problems and to initiate communication about these subjects.

The many facets of involuntary childlessness in general practice

OBJECTIVE

To obtain a vivid picture of involuntary childlessness in general practice so that the doctor becomes aware of the frequency and the forms of childlessness.

DESIGN

Analysis of in-depth interviews.

SETTING

General practices in the area of Göttingen, Germany.

SUBJECTS

35 patients (27 females) who described themselves as involuntarily childless.

MAIN OUTCOME MEASURES

Family status, reason for childlessness as seen from the patient's perspective, treatment status, and expectations towards the general practitioner (GP).

RESULTS

Eleven patients had one or more children resulting, either from the present partnership or from a previous partnership. A deficient hormone status (7 patients) and tubal disorders (7) were most frequently reported by the patients. Some patients reported several reasons. In four cases, childlessness was directly or indirectly caused by problems within the partnership. Only eight interviewees or their partners were receiving active treatment at the current time. An additional eight couples had been previously treated. Medical information and emotional support were most often expected from the GP, but not always received--because of lack of time, lack of trust or lack of initiative on the doctor's part.

CONCLUSIONS

Since social reasons, problems with the partnership or anxieties may cause childlessness or may be associated with somatic causes, the GP should consider infertility in the broader context of family medicine. Although not all childless patients do expect immediate diagnosis, referral and treatment for their condition, they are often waiting for the GP's initiative to talk about their problems.

[Is "involuntary childlessness" within the realm of family medicine responsibility of the general practitioner?]

The aim of the study was to assess whether or not management of infertility is within the domain of the general practitioner in his capacity as a family physician. All accredited family physicians in the wider area of Goettingen were invited to take part in our survey. A total of 57 doctors (84%) participated. In personal interviews the family physicians were encouraged to frankly discuss the following main topics: the frequency of infertility in their own practice as well as their care for and attitudes towards infertile patients. Many family physicians interviewed were reluctant to address involuntary childlessness and underestimated its frequency. According to their patients' needs and demands, however, family doctors--above all in rural practices--have been participating in the screening and counseling of, and providing emotional support for, involuntarily childless patients. A qualitative analysis of the interview data revealed that many family physicians regarded infertility as the patients' private matter and placed it within the domain of specialists. About one-third of the physicians expressed negative attitudes towards infertile patients. Moreover, assisted reproduction techniques were sometimes rejected as "unnatural" methods. If a family-oriented approach should be amplified in family practice by offering supportive counseling for infertile patients, continuing medical education will have to take these attitudes into account.

Management of involuntary childlessness in general practice--patients' and doctors' views

In order to determine whether general practitioners (GPs) are interested in infertility counselling and whether infertile patients seek help from their family doctor, we personally interviewed doctors and infertile patients. Almost all of the board-certified GPs in Göttingen, Germany, and two independent samples of infertile women and men attending the Göttingen University Hospital participated. The majority of the GPs did not routinely ask childless patients about their desire to have children, although half of the infertile men and one-quarter of the infertile women would prefer it if their doctor were to raise the subject. About half of these doctors emphasized their role as an important source of information and advice during assisted conception and almost half of the patients expected emotional support from their GP.

Management of involuntary childlessness

Any definition of involuntary childlessness has to consider the difference between sterility and subfertility. As the latter affects about 20-30% of all couples at least once in their lives, general practitioners (GPs) may be the first to be confronted with this problem. This review presents the most relevant diagnostic and therapeutic options in cases of female or male infertility, and discusses the new assisted reproductive technologies (such as insemination, in vitro fertilization, gamete transfer and intracytoplasmatic sperm injection) so that GPs may adequately inform their patients about these procedures and their risks and outcomes. Although controversial, involuntary childlessness and its clinical treatment seem to have a strong psychological impact on a couple's social, emotional and sexual life. Being available for discussion with childless couples and offering ongoing support may be the most important role for the GP in this context.