Downregulation of LRRC8A protects human ovarian and alveolar carcinoma cells against Cisplatin-induced expression of p53, MDM2, p21^Waf1/Cip1 and Caspase-9/-3 activation

The leucine-rich repeat containing 8A (LRRC8A) protein is an essential component of the volume-sensitive organic anion channel (VSOAC), and using pharmacological anion channel inhibitors (NS3728, DIDS) and LRRC8A siRNA we have investigated its role in development of Cisplatin resistance in human ovarian (A2780) and alveolar (A549) carcinoma cells. In Cisplatin-sensitive cells Cisplatin treatment increases p53-protein level as well as downstream signaling, e.g., expression of p21(Waf1/Cip1), Bax, Noxa, MDM2, and activation of Caspase-9/-3. In contrast, Cisplatin-resistant cells do not enter apoptosis, i.e., their p53 and downstream signaling are reduced and caspase activity unaltered following Cisplatin exposure. Reduced LRRC8A expression and VSOAC activity are previously shown to correlate with Cisplatin resistance, and here we demonstrate that pharmacological inhibition and transient knockdown of LRRC8A reduce the protein level of p53, MDM2, and p21(Waf1/Cip1) as well as Caspase-9/-3 activation in Cisplatin-sensitive cells. Cisplatin resistance is accompanied by reduction in total LRRC8A expression (A2780) or LRRC8A expression in the plasma membrane (A549). Activation of Caspase-3 dependent apoptosis by TNFα-exposure or hyperosmotic cell shrinkage is almost unaffected by pharmacological anion channel inhibition. Our data indicate 1) that expression/activity of LRRC8A is essential for Cisplatin-induced increase in p53 protein level and its downstream signaling, i.e., Caspase-9/-3 activation, expression of p21(Waf1/Cip1) and MDM2; and 2) that downregulation of LRRC8A-dependent osmolyte transporters contributes to acquirement of Cisplatin resistance in ovarian and lung carcinoma cells. Activation of LRRC8A-containing channels is upstream to apoptotic volume decrease as hypertonic cell shrinkage induces apoptosis independent of the presence of LRRC8A

Exploring needs, barriers to, and facilitators of rehabilitation exercise following revision hip replacement - a grounded theory study

Purpose: Evidence on rehabilitation after revision total hip replacement (THR) is inadequate and development of rehabilitation interventions is warranted. Even so, little is known about patients’ experiences with revision THR rehabilitation. This study aimed to explore patients' rehabilitation exercise experiences after revision THR.Materials and methods: Using constructivist grounded theory, we conducted semi-structured qualitative interviews with twelve patients with completed or almost completed rehabilitation exercise after revision THR. Data collection and analysis were a constant comparative process conducted in three phases; initial, focused, and theoretical.Findings: From the data, we generated a substantial theory of the participant’s circumstances and ability to integrate rehabilitation exercise into their everyday life after revision THR. Four categories were constructed based on patients’ experiences in different contexts: hesitance, fear avoidance, self-commitment, and fidelity.Conclusions: This study highlighted that patients’ expectations, past experiences, attitudes, trusts, engagement, and circumstances interact to influence engagement and adherence to rehabilitation exercise and described four categories relating to the integration of THR rehabilitation exercise into their everyday life. Clinicians should be aware of and account for these categories during rehabilitation exercise. Tailored individual rehabilitation exercise interventions and clinician approaches to optimize commitment and adherence are needed among patients with revision THR